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  • Inorganic Chemistry  (4,698)
  • Aircraft Stability and Control
  • 2015-2019  (68)
  • 1955-1959  (3,139)
  • 1950-1954  (1,662)
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  • 1
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    Lessons from Modeling Flexible Aircraft for Active Flutter Suppression (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: These slides describe a method and technology of modeling flexible aircraft for active control of structural dynamics. Objective: Generate models useful for the design and evaluation of control laws for active structural control and flutter suppression that are able to accurately predict body freedom flutter.
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN66921 , Aerospace Control and Guidance Systems Committee (ACGSC) Meeting; Mar 27, 2019 - Mar 29, 2019; Santa Fe, NM; United States
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  • 2
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    Time-varying Weights in Multi-Objective Optimal Control for Flexible Wing Aircraft (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: A multi-objective optimal control technique is modified to accommodate changing cost function weights and is used to control a flexible wing aircraft model. Variation of the weights is used to adjust the relative importance of each objective according to either a prescribed function of time or of the state. Several techniques for obtaining a practical approximation to the optimal control solution are presented, and stability of a specific weight structure with the optimal controller is demonstrated. Functionality of the multi-objective control design with weight variation is demonstrated in simulation of a flexible wing transport aircraft and is shown to improve performance over the fixed weight version both at a constant flight condition and across changing flight conditions.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN64647 , AIAA SciTech Forum 2019; Jan 07, 2019 - Jan 11, 2019; San Diego, CA; United States
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  • 3
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    Multi-Objective Optimal Control of the 6-DoF Aeroservoelastic Common Research Model with Aspect Ratio 13.5 Wing (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: A new 6-DoF aeroservoelastic (ASE) Common Research Model (CRM) provided by The Boeing Company with aspect ratio 13.5 and 17 control surfaces per wing is utilized to demonstrate combined tracking and optimal multi-objective control. The multi-objective controller is derived on the closed loop tracking controller, and utilizes state and gust estimates provided by an extended state observer. Various methods of model reduction useful for control and estimation are presented. A computationally efficient MATLAB/Simulink simulation is presented which includes actuator dynamics, rate and deflection saturation limits, and gust disturbance inputs. The platform is used to demonstrate excellent 6-DoF tracking control performance coupled with the multi-objective controller, which is shown to effectively reduce structural mode movement, wing root bending moment, and drag. State and gust estimation is also shown to perform well, even when derived and/or implemented with significantly fewer states than the original full-sized model.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN271828 , AIAA Science and Technology Forum and Exposition; Jan 07, 2019 - Jan 11, 2019; San Diego, CA; United States
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  • 4
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    Surviving the Improbable: Upset Prevention and Recovery in Flight Control (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: Slides for an invited presentation (as part of a series) at Santa Clara University, invited by prof. Mohammad Ayoubi. The slides are an overview and summary of past and current research projects in the field of envelope protection, upset prevention and stall recovery guidance, with the aim to avoid loss of control accidents and improve safety in air transportation. The overall aim of this presentation series is to inspire students and to show them possible opportunities that they can pursue for their later careers paths.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN52363 , Santa Clara University Invited Lecture Series; Santa Clara, CA; United States
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  • 5
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    MRAC with Time-Varying Reference Model from Convex Combination (2019)
    In:  CASI
    Details
    Publication Date: 2019-09-13
    Description: An extension of model reference adaptive control is presented that accommodates use of a time-varying reference model. Specifically, the reference model is taken to be a time-varying convex combination of two linear, time-invariant models. The design is intended to act as a way to smoothly transition between two different reference models without resorting to a scheduled switch. It also provides the ability to use an interpolated reference model when the plant is operating between design points. The time variation of the combination must satisfy some requirements to ensure stability but is otherwise user choice. Subject to these requirements, bounded tracking error behavior is demonstrated via Lyapunov stability analysis for the single-input, single-output, output feedback case. Tracking error convergence is asymptotic when time variation ceases. The proposed design is demonstrated in simulation of a numerical model.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN66631 , American Control Conference; Jul 10, 2019 - Jul 12, 2019; Philadelphia, PA; United States
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  • 6
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    NASA Armstrong Flight Research Center Dynamics and Controls (530) (2019)
    In:  CASI
    Details
    Publication Date: 2019-10-30
    Description: No abstract available
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN74004
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  • 7
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    Verification of a Motion Cueing Strategy for Stall Recovery Training in a Commercial Transport Simulator (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper verifies a motion cueing strategy for improved pilot stall recovery training in commercial transport simulators. Eight airline transport pilots flew a high-altitude stall recovery task in the NASA B747 level-D-certified full flight simulator under three different motion configurations: no motion, baseline motion, and enhanced motion. For each motion condition, pilots performed the task with both baseline aircraft dynamics and aircraft dynamics enhanced with lateral-directional characteristics of the airplane at angle of attack approaching stall. Motion configuration significantly affected: 1) pilot opinions on the helpfulness of motion in performing the task, 2) the maximum roll angle in the stall maneuver, 3) the minimum load factor in the recovery, 4) the number of secondary stick shakers in the stall recovery, and 5) the maximum airspeed in the recovery. The two different aircraft dynamics significantly affected: 1) pilot opinions on the noticeability of the banking roll off near the stall and 2) the maximum roll angle in the stall maneuver. These results indicate that the relatively minor enhancements to the motion logic of heritage commercial transport simulators presented here can significantly improve pilot performance in simulated stall recoveries, and potentially improve stall recovery training.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN65276 , AIAA SciTech Forum 2019; Jan 07, 2019 - Jan 11, 2019; San Diego, CA; United States
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  • 8
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    Flight Control Research at NASA Ames (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An overview of the flight control work in the Intelligent Systems Division at NASA Ames is presented. The highlight focuses on efforts surrounding performance-adaptive aeroelastic wing shaping for aircraft with flexible wings. Topics covered include aeroservoelastic modeling capabilities, online drag-optimizing control designs, gust and maneuver load alleviation techniques, and related wind tunnel demonstrations.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN67091 , Aerospace Control and Guidance Systems Committee Meeting; Mar 27, 2019 - Mar 29, 2019; Santa Fe, NM; United States
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  • 9
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    CPAS Main Parachute Cluster Asymmetry: A Second Look (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aircraft Stability and Control
    Type: JSC-E-DAA-TN69878-2 , AIAA AVIATION Forum and Exposition; Jun 17, 2019 - Jun 21, 2019; Dallas, TX; United States
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  • 10
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    Revisit of Load Asymmetry Observed During Orion Main Parachute Inflation (2019)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aircraft Stability and Control
    Type: JSC-E-DAA-TN69878-1 , AIAA AVIATION Forum and Exposition; Jun 17, 2019 - Jun 21, 2019; Dallas, TX; United States
    Format: text
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  • 11
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    Fast Sensitivity-Based Optimal Trajectory Updates for Descent Operations Subject to Time Constraints (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: The ability to meet a controlled time of arrival during a continuous descent operation will enable environmentally friendly and fuel efficient descent operations while simultaneously maintaining airport throughput. Previous work showed that guidance strategies based on a frequent recalculation of the optimal trajectory during the descent result in excellent environmental impact mitigation figures while meeting operational constraints in the presence of modelling errors. However, the time lag of recalculating the trajectory using traditional optimisation algorithms could lead to performance degradation and stability issues. This paper proposes an alternative strategy, which allows for fast updates of the optimal trajectory based on parametric sensitivities. Promising results show that the performance of this method is comparable to that of instantaneously recalculating the optimal descent trajectory at each time sample.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-30424 , AIAA/IEEE Digital Avionics Systems Conference (DASC); Sep 23, 2018 - Sep 27, 2018; London, England; United Kingdom
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  • 12
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    Frequency-Domain Deconvolution for Flight Dynamics Applications (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: A deconvolution method is presented for estimating input data from measured output data and a model of the dynamic process involved. The method uses an optimal Wiener filter for separating the measured data into signal and noise components, and a high-accuracy Fourier transform for inverting the model dynamics in the frequency domain. The method is an extension of optimal Fourier smoothing, and uses a technique to enhance the contrast between the signal and noise spectra in designing the Wiener filter. The deconvolution method was applied to simulation and flight test data for the purposes of removing unwanted distortions introduced by signal-conditioning filters and sensor dynamics, and for reconstructing turbulence inputs from measured sensor data. Results indicated hat the method performs well given good signal-to-noise levels and accurate models of the dynamic process.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-28783 , AIAA Aviation and Aeronautics Forum and Exposition; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 13
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    Real-Time Parameter Estimation for Flexible Aircraft (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: A method for estimating aeroelastic stability and control derivatives for flexible aircraft is developed and demonstrated using flight test data for the X-56A subscale demonstrator. The method uses the equation-error approach with frequency-domain data, and can be applied post-flight or in real time during flight. The non-dimensional aeroelastic forces and moments and the explanatory variables (including generalized displacement, rate, and acceleration states for the vibration modes) are estimated using a finite element model and onboard sensor measurements in both a least squares and Kalman filtering framework. The data are then transformed into the frequency domain for parameter estimation using equation error. This method can result in a more efficient analysis than with other iterative methods, and can leverage existing statistical tools for model structure determination, data collinearity detection, combining multiple maneuvers or prior information, and others to improve model quality.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-28533 , AIAA Aviation and Aeronautics Forum (Aviation 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 14
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    Active Flutter Suppression Controllers Derived from Linear and Nonlinear Aerodynamics: Application to a Transport Aircraft Model (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: Active flutter suppression has been demonstrated in simulation by many researchers, generally using methods based on linear aerodynamics and often with simplistic geometries. In this paper, active flutter suppression is demonstrated in a simulation using a Navier-Stokes aerodynamics code, FUN3D (Fully Unstructured Navier-Stokes Three-Dimensional), and a realistic transport aircraft configuration. This is accomplished using simple observer-feedback controllers derived from linear aeroelastic models, including reduced order models built via FUN3D data. The development of these reduced order models is described here. It is shown that controllers derived from reduced order models of the nonlinear aerodynamics outperform controllers based on linear aerodynamics.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-28523 , AIAA Aviation and Aeronautics Forum (Aviation 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 15
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    Piloted Simulator Evaluation Results of Flight Physics Based Stall Recovery Guidance (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: In recent studies, it has been observed that loss of control in flight is the most frequent primary cause of accidents. A significant share of accidents in this category can be remedied by upset prevention if possible, and by upset recovery if necessary, in this order of priorities. One of the most important upsets to be recovered from is stall. Recent accidents have shown that a correct stall recovery maneuver remains a big challenge in civil aviation, partly due to a lack of pilot training. A possible strategy to support the flight crew in this demanding context is calculating a recovery guidance signal, and showing this signal in an intuitive way on one of the cockpit displays, for example by means of the flight director. Different methods for calculating the recovery signal, one based on fast model predictive control and another using an energy based approach, have been evaluated in four relevant operational scenarios by experienced commercial as well as test pilots in the Vertical Motion Simulator at NASA Ames Research Center. Evaluation results show that this approach could be able to assist the pilots in executing a correct stall recovery maneuver.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN50867 , SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 16
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    Development of an Integrated Nonlinear Aeroservoelastic Flight Dynamic Model of the NASA Generic Transport Model (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper describes a recent development of an integrated fully coupled aeroservoelastic flight dynamic model of the NASA Generic Transport Model (GTM). The integrated model couples nonlinear flight dynamics to a nonlinear aeroelastic model of the GTM. The nonlinearity includes the coupling of the rigid-body aircraft states in the partial derivatives of the aeroelastic angle of attack. Aeroservoelastic modeling of the control surfaces which are modeled by the Variable Camber Continuous Trailing Edge Flap is also conducted. The R.T. Jones' method is implemented to approximate unsteady aerodynamics. Simulations of the GTM are conducted with simulated continuous and discrete gust loads..
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN50754 , AIAA SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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  • 17
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    Computational Fluid Dynamics Analysis of the Stall Characteristics of a Wing Design Based on Prandtl's Minimum Induced Drag (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Stall characteristics of a wing whose design was based on Prandtls minimum induced drag analysis is presented. Flow field is resolved using RANS CFD (Computational Fluid Dynamics) solver OVERFLOW-2. Both in freestream and in ground effect are analyzed. In addition, effect of low-Mach preconditioner on the stall characteristic is presented. Results show that simulations that lack preconditioner predicts higher stall angle as well as much more benign behavior near the stall angle. Stall analysis in freestream show that flow begins to separate at the inboard region. The flow at the tip remains attached until approximately 19.0 degrees angle of attack.
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN48257 , AIAA Applied Aerodynamics Conference; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States|AIAA Aviation and Aeronautics Forum (Aviation 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 18
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    Design, Development, and Flight Evaluation of Pilot Displays and Long-Track Control for Wake Surfing Applications (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: These slides are the companion to the paper on the ACT experiment flown using a G-III autopilot and ADS-B datalink.
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN58037 , AIAA Aviation Forum; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 19
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    Spanwise Adaptive Wing (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This presentation discusses the NASA Armstrong PTERA-SAW flight simulation. The uses of this simulation are to study the aerodynamic effects of moving outer wing panels in flight, develop a flight control system, flight safety analysis, mission planning, flight envelope expansion, and post-flight data analysis.
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN57916 , AIAA Aviation 2018; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 20
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    Formation Flight System Extremum-Seeking-Control Using Blended Performance Parameters (2018)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: An extremum-seeking control system for formation flight that uses blended performance parameters in a conglomerate performance function that better approximates drag reduction than performance functions formed from individual measurements. Generally, a variety of different measurements are taken and fed to a control system, the measurements are weighted, and are then subjected to a peak-seeking control algorithm. As measurements are continually taken, the aircraft will be guided to a relative position which optimizes the drag reduction of the formation. Two embodiments are discussed. Two approaches are shown for determining relative weightings: "a priori" by which they are qualitatively determined (by minimizing the error between the conglomerate function and the drag reduction function), and by periodically updating the weightings as the formation evolves.
    Keywords: Aircraft Stability and Control
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  • 21
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    Dynamics and Control of In-Flight Wing Tip Docking (2018)
    In:  CASI
    Details
    Publication Date: 2019-10-19
    Description: Project Link! is a NASA-led effort to study the feasibility of multi-aircraft aerial docking systems. In these systems, a group of vehicles physically link to each other during flight to form a larger ensemble vehicle with increased aerodynamic performance and mission utility. This paper presents a dynamic model and control architecture for a system of fixed-wing vehicles with this capability. The dynamic model consists of the 6 degree-of-freedom fixedwing aircraft equations of motion, a spring-damper-magnet system to represent the linkage force between constituent vehicles, and the NASA-Burnham-Hallock wingtip vortex model to represent the close-proximity aerodynamic interactions between constituents before the linking occurs. The control architecture consists of a guidance algorithm to autonomously drive the constituents towards their linking partners and an inner-loop angular rate controller. A simulation was constructed from the model, and the flight dynamic modes of the linked system were compared to the individual vehicles. The main contributions of this work are twofold. First is the introduction of close-proximity aerodynamic effects to create a realistic simulation framework for this problem. Second is the application of a sophisticated leaderfollower guidance algorithm to achieve in-air wingtip docking. Simulation results for both before and after linking are presented.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-28646 , Journal of Guidance, Control, and Dynamics (ISSN 0731-5090) (e-ISSN 1533-3884); 41; 11; 2327-2337
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  • 22
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    Output Measurement Equations for Flexible Aircraft Flight Dynamics (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A summary of output measurement equations for onboard sensors used in flight testing of flexible aircraft is presented. These equations include the effects of structural flexibility and are considerably more complex than the standard equations for rigid-body aircraft. The output equations discussed include accelerations from linear accelerometers, strains, angular rates, angular accelerations, Euler angles, true airspeed, and air flow angles. The output equations are derived in full form and then simplified in some cases. Linearized output equations, suitable for state-space or transfer function models, are also developed. Example flight test data from the X-56A subscale aeroelastic demonstrator is discussed, for reference.
    Keywords: Aircraft Stability and Control
    Type: NASA/TM-2018-220102 , L-20956 , NF1676L-31027
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  • 23
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    Design, Development, and Flight Evaluation of Pilot Displays and Long-Track Control for Wake Surfing Applications (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: From April to May 2017, the National Aeronautics and Space Administration Armstrong Flight Research Center completed a series of flights with a trail C-20A airplane surfing in the wake of a Gulfstream III airplane using a commercially available datalink as the primary communication between the two aircraft. The purpose of this test was to characterize the aerodynamic benefits received by the trail airplane flying in the upwash portion of the wake generated from the lead airplane. Lateral and vertical relative position to the wake were automatically controlled through an experimental programmable autopilot on the C-20A airplane. Long-track, the separation distance between the two aircraft, was maintained by test pilots managing throttle position using customized cockpit displays. These displays provided the pilots with throttle cues for maintaining long-track position and situational awareness of the wake vortex relative to the position of the trail airplane. Flight testing demonstrated the ability of the pilots to use these displays to maintain a safe long-track distance, but found there to be trades between tracking performance and the frequency of throttle motion. The wake awareness display provided the pilots with adequate situational awareness of the wake vortex during the flight experiment. This paper presents a summary of the design, development, and flight evaluation of the pilot displays and long-track control.
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN54320 , AIAA Aviation and Aeronautics Forum and Exposition; Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 24
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    [Editors' Choice] Fluorine frolicking with eight friends (2017)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2017-02-10
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 25
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    [This Week in Science] A salty route to an all-nitrogen ring (2017)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2017-01-27
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 26
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    [Perspective] Polynitrogen chemistry enters the ring (2017)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2017-01-27
    Description: Polynitrogens have the potential for ultrahigh-performing explosives or propellants because singly or doubly bonded polynitrogens can decompose to triply bonded dinitrogen (N2) with an extraordinarily large energy release. The large energy content and relatively low activation energy toward decomposition makes the synthesis of a stable polynitrogen allotrope an extraordinary challenge. Many elements exist in different forms (allotropes)—for example, carbon can exist as graphite, diamond, buckyballs, or graphene. However, no stable neutral allotropes are known for nitrogen, and only two stable homonuclear polynitrogen ions had been isolated until now—namely, the N3− anion (1) and the N5+ cation (2). On page 374 of this issue, Zhang et al. (3) report the synthesis and characterization of the first stable salt of the cyclo-N5− anion, only the third stable homonuclear polynitrogen ion ever isolated. Author: Karl O. Christe
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 27
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    Flight-Test Techniques for Quantifying Pitch Rate and Angle-of-Attack Rate Dependencies (2017)
    In:  CASI
    Details
    Publication Date: 2019-06-11
    Description: Three different types of maneuvers were designed to separately quantify the pitch rate and angle-of-attack rate contributions to the nondimensional aerodynamic pitching moment coefficient. These maneuvers combined pilot inputs and automatic multisine excitations, and they were demonstrated with the subscale T-2 and Bat-4 airplanes using the NASA Airborne Subscale Transport Aircraft Research flight-test facility. Stability and control derivatives (in particular, Cmq and Cm) were accurately estimated from the flight-test data. These maneuvers can be performed with many types of aircraft, and the results can be used to improve physical insight into the flight dynamics, facilitate more accurate comparisons with wind-tunnel experiments or numerical investigations, and increase simulation prediction fidelity.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-26357 , Journal of Aircraft (ISSN 0021-8669) (e-ISSN 1533-3868); 54; 6; 2367-2377
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    NASA TECHNICAL REPORTS
  • 28
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    Low-Speed Stability and Control Test of a "Double-Bubble" Transport Configuration (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: A test in the Langley 12-Foot Low-Speed Tunnel was conducted as a risk mitigation effort to quickly obtain some low-speed stability and control data on a "double-bubble" or D8 transport configuration. The test also tested some configuration design trades. A 5-percent scale model was tested with stabilizer, elevator, rudder and aileron control deflections. This report summarizes the test results.
    Keywords: Aircraft Stability and Control
    Type: NASA/TM-2017-219797 , L-20897 , NF1676L-29029
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  • 29
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    Attitude Estimation: With or Without Spacecraft Dynamics? (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: Kalman filter based spacecraft attitude estimation has been used in many space missions and has been widely discussed in literature. While some models in spacecraft attitude estimation include spacecraft dynamics, most do not. To our best knowledge, there is no analysis to determine which model is a better choice. In this paper, we discuss the reasons why spacecraft dynamics should be considered in the Kalman filter based spacecraft attitude estimation problem. We also propose a reduced quaternion spacecraft dynamics model which admits additive noise. Geometry of the reduced quaternion model and the additive noise are discussed. This formulation makes computation easier than the one with full quaternion. Simulations are conducted to justify our claims.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-24892 , Advances in Aircraft and Spacecraft Science (ISSN 2287-528X) (e-ISSN 2287-5271); 4; 3; 335-351
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    Design and Control of an Experimental Tilt-Wing Aircraft (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: In this project, work has been done in the field of conceptual design of experimental tiltrotors. The main tools that have been used are NDARC (NASA Design and Analysis of Rotorcraft) and SIMPLI-FLYD. NDARC is a conceptual design tool for rotorcraft, and it is used to find trim points under various flight conditions. SIMPLI-FLYD is an integrated collection of software tools that enables a flight dynamics and control assessment of the rotorcraft vehicle design generated from NDARC. Two different tiltrotors have been investigated. Initially, work was done with the Bell XV- 15 tiltrotor. NDARCs ability to correctly model the tiltwing transition between airplane mode and hover mode was looked into. In addition, data from old flight tests were compared to the NDARC output, to see how accurately performance could be predicted. After the XV-15 analysis, an NDRARC model of a novel tiltwing concept from Elytron Aircraft was written and analyzed together with SIMPLI-FLYD. Elytron 2S is an experimental tiltwing aircraft, consisting of a joined-wing design with a small central wing for the proprotor. An alternative approach to hover control is used, where the typical rotor hub and swash plate are substituted for linear actuators controlling pitch, yaw and roll. The objective with the analysis of Elytron is to obtain a more complete understanding of the maneuverability and possible performance of this alternative aircraft configuration.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN39203 , NASA/CR-2017-219456
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    Performance Optimizing Adaptive Control with Time-Varying Reference Model Modification (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper presents a new adaptive control approach that involves a performance optimization objective. The control synthesis involves the design of a performance optimizing adaptive controller from a subset of control inputs. The resulting effect of the performance optimizing adaptive controller is to modify the initial reference model into a time-varying reference model which satisfies the performance optimization requirement obtained from an optimal control problem. The time-varying reference model modification is accomplished by the real-time solutions of the time-varying Riccati and Sylvester equations coupled with the least-squares parameter estimation of the sensitivities of the performance metric. The effectiveness of the proposed method is demonstrated by an application of maneuver load alleviation control for a flexible aircraft.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN42886 , Eighteenth Yale Workshop on Adaptive and Learning Systems; Jun 21, 2017 - Jun 23, 2017; New Haven, CT; United States
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    Estimation, Navigation and Control of Multi-Rotor Drones in an Urban Wind Field (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The paper presents an on-board estimation, navigation and control architecture for multi-rotor drones flying in urban environment. It consists of adaptive algorithms to estimate vehicle's aerodynamic drag coefficients with respect to still air and the urban wind components along the flight trajectory, with guaranteed fast and reliable convergence to the true values; navigation algorithms to generate feasible trajectories between given way-points that take into account the estimated wind; and of control algorithms to track the generated trajectories as long as the vehicle retains sufficient number of functioning rotors capable of compensating for the estimated wind. All components of this on-board system are computationally effective and are intended for a real time implementation. The algorithms were tested in simulations.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN38102 , AIAA SciTech Forum; Jan 09, 2017 - Jan 13, 2017; Grapevine, TX; United States
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    Fuzzy Logic Controller Stability Analysis Using a Satisfiability Modulo Theories Approach (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: While many widely accepted methods and techniques exist for validation and verification of traditional controllers, at this time no solutions have been accepted for Fuzzy Logic Controllers (FLCs). Due to the highly nonlinear nature of such systems, and the fact that developing a valid FLC does not require a mathematical model of the system, it is quite difficult to use conventional techniques to prove controller stability. Since safety-critical systems must be tested and verified to work as expected for all possible circumstances, the fact that FLC controllers cannot be tested to achieve such requirements poses limitations on the applications for such technology. Therefore, alternative methods for verification and validation of FLCs needs to be explored. In this study, a novel approach using formal verification methods to ensure the stability of a FLC is proposed. Main research challenges include specification of requirements for a complex system, conversion of a traditional FLC to a piecewise polynomial representation, and using a formal verification tool in a nonlinear solution space. Using the proposed architecture, the Fuzzy Logic Controller was found to always generate negative feedback, but inconclusive for Lyapunov stability.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN38074 , SciTech 2017; Jan 09, 2017 - Jan 13, 2017; Grapevine, TX; United States
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    An Analysis of the Optimal Control Modification Method Applied to Flutter Suppression (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Unlike basic Model Reference Adaptive Control (MRAC)l, Optimal Control Modification (OCM) has been shown to be a promising MRAC modification with robustness and analytical properties not present in other adaptive control methods. This paper presents an analysis of the OCM method, and how the asymptotic property of OCM is useful for analyzing and tuning the controller. We begin with a Lyapunov stability proof of an OCM controller having two adaptive gain terms, then the less conservative and easily analyzed OCM asymptotic property is presented. Two numerical examples are used to show how this property can accurately predict steady state stability and quantitative robustness in the presence of time delay, and relative to linear plant perturbations, and nominal Loop Transfer Recovery (LTR) tuning. The asymptotic property of the OCM controller is then used as an aid in tuning the controller applied to a large scale aeroservoelastic longitudinal aircraft model for flutter suppression. Control with OCM adaptive augmentation is shown to improve performance over that of the nominal non-adaptive controller when significant disparities exist between the controller/observer model and the true plant model.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN50278 , AIAA SciTech Forum; Jan 08, 2018 - Jan 12, 2018; Kissimmee, FL; United States
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    Advanced Control and Autonomy Research (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This presentation is given at a NASA DLR (German Aerospace Center) meeting at NASA ARC on March 14, 2017. The presentation provides an overview of the Advanced Control and Evolvable Systems (ACES) group at NASA ARC and the research areas in UAS autonomy, stall recovery guidance, and flexible aircraft flight control.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN39958 , NASA/DLR Collaboration Meeting; Mar 14, 2017; Moffett Field, CA; United States
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    Automated Re-Entry System using FNPEG (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper discusses the implementation and simulated performance of the FNPEG (Fully Numerical Predictor-corrector Entry Guidance) algorithm into GNC FSW (Guidance, Navigation, and Control Flight Software) for use in an autonomous re-entry vehicle. A few modifications to FNPEG are discussed that result in computational savings -- a change to the state propagator, and a modification to cross-range lateral logic. Finally, some Monte Carlo results are presented using a representative vehicle in both a high-fidelity 6-DOF (degree-of-freedom) sim as well as in a 3-DOF sim for independent validation.
    Keywords: Aircraft Stability and Control
    Type: JSC-CN-38080 , AIAA SciTech Forum 2017; Jan 09, 2017 - Jan 13, 2017; Grapevine, TX; United States
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    Link!: Potential Field Guidance Algorithm for In-Flight Linking of Multi-Rotor Aircraft (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Link! is a multi-center NASA e ort to study the feasibility of multi-aircraft aerial docking systems. In these systems, a group of vehicles physically link to each other during flight to form a larger ensemble vehicle with increased aerodynamic performance and mission utility. This paper presents a potential field guidance algorithm for a group of multi-rotor vehicles to link to each other during flight. The linking is done in pairs. Each vehicle first selects a mate. Then the potential field is constructed with three rules: move towards the mate, avoid collisions with non-mates, and stay close to the rest of the group. Once a pair links, they are then considered to be a single vehicle. After each pair is linked, the process repeats until there is only one vehicle left. The paper contains simulation results for a system of 16 vehicles.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-27073 , AIAA Aviation and Aeronautics Forum and Exposition (AIAA Aviation 2017); Jun 05, 2017 - Jun 09, 2017; Denver, CO; United States
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    High-Fidelity Multi-Rotor Unmanned Aircraft System Simulation Development for Trajectory Prediction Under Off-Nominal Flight Dynamics (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The NASA Unmanned Aircraft System (UAS) Traffic Management (UTM) project is conducting research to enable civilian low-altitude airspace and UAS operations. A goal of this project is to develop probabilistic methods to quantify risk during failures and off nominal flight conditions. An important part of this effort is the reliable prediction of feasible trajectories during off-nominal events such as control failure, atmospheric upsets, or navigation anomalies that can cause large deviations from the intended flight path or extreme vehicle upsets beyond the normal flight envelope. Few examples of high-fidelity modeling and prediction of off-nominal behavior for small UAS (sUAS) vehicles exist, and modeling requirements for accurately predicting flight dynamics for out-of-envelope or failure conditions are essentially undefined. In addition, the broad range of sUAS aircraft configurations already being fielded presents a significant modeling challenge, as these vehicles are often very different from one another and are likely to possess dramatically different flight dynamics and resultant trajectories and may require different modeling approaches to capture off-nominal behavior. NASA has undertaken an extensive research effort to define sUAS flight dynamics modeling requirements and develop preliminary high fidelity six degree-of-freedom (6-DOF) simulations capable of more closely predicting off-nominal flight dynamics and trajectories. This research has included a literature review of existing sUAS modeling and simulation work as well as development of experimental testing methods to measure and model key components of propulsion, airframe and control characteristics. The ultimate objective of these efforts is to develop tools to support UTM risk analyses and for the real-time prediction of off-nominal trajectories for use in the UTM Risk Assessment Framework (URAF). This paper focuses on modeling and simulation efforts for a generic quad-rotor configuration typical of many commercial vehicles in use today. An overview of relevant off-nominal multi-rotor behaviors will be presented to define modeling goals and to identify the prediction capability lacking in simplified models of multi-rotor performance. A description of recent NASA wind tunnel testing of multi-rotor propulsion and airframe components will be presented illustrating important experimental and data acquisition methods, and a description of preliminary propulsion and airframe models will be presented. Lastly, examples of predicted off-nominal flight dynamics and trajectories from the simulation will be presented.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-25779 , 2017 AIAA Aviation and Aeronautics Forum; Jun 05, 2017 - Jun 09, 2017; Denver, CO; United States
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    Simulation Evaluation of Pilot Inputs for Real Time Modeling During Commercial Flight Operations (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Aircraft dynamics characteristics can only be identified from flight data when the aircraft dynamics are excited sufficiently. A preliminary study was conducted into what types and levels of manual piloted control excitation would be required for accurate Real-Time Parameter IDentification (RTPID) results by commercial airline pilots. This includes assessing the practicality for the pilot to provide this excitation when cued, and to further understand if pilot inputs during various phases of flight provide sufficient excitation naturally. An operationally representative task was evaluated by 5 commercial airline pilots using the NASA Ice Contamination Effects Flight Training Device (ICEFTD). Results showed that it is practical to use manual pilot inputs only as a means of achieving good RTPID in all phases of flight and in flight turbulence conditions. All pilots were effective in satisfying excitation requirements when cued. Much of the time, cueing was not even necessary, as just performing the required task provided enough excitation for accurate RTPID estimation. Pilot opinion surveys reported that the additional control inputs required when prompted by the excitation cueing were easy to make, quickly mastered, and required minimal training.
    Keywords: Aircraft Stability and Control
    Type: NASA/CR-2017-219600
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    Guidance, Navigation, and Control Analysis Activities at MSFC (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aircraft Stability and Control
    Type: M17-5798 , NESC GNC Technical Discipline Team Face-to-Face Meeting; Jan 23, 2017 - Jan 27, 2017; Mountain View, CA; United States
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    Flight Test Techniques for Quantifying Pitch Rate and Angle of Attack Rate Dependencies (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Three different types of maneuvers were designed to separately quantify pitch rate and angle of attack rate contributions to the nondimensional aerodynamic pitching moment coefficient. These maneuvers combined pilot inputs and automatic multisine excitations, and were own with the subscale T-2 and Bat-4 airplanes using the NASA AirSTAR flight test facility. Stability and control derivatives, in particular C(sub mq) and C(sub m alpha(.)) were accurately estimated from the flight test data. These maneuvers can be performed with many types of aircraft, and the results can be used to increase simulation prediction fidelity and facilitate more accurate comparisons with wind tunnel experiments or numerical investigations.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-24686 , 2017 AIAA SciTech; Jan 09, 2017 - Jan 13, 2017; Dallas, TX; United States
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    Fuzzy Logic Controller Stability Analysis Using a Satisfiability Modulo Theories Approach (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: While many widely accepted methods and techniques exist for validation and verification of traditional controllers, at this time no solutions have been accepted for Fuzzy Logic Controllers (FLCs). Due to the highly nonlinear nature of such systems, and the fact that developing a valid FLC does not require a mathematical model of the system, it is quite difficult to use conventional techniques to prove controller stability. Since safety-critical systems must be tested and verified to work as expected for all possible circumstances, the fact that FLC controllers cannot be tested to achieve such requirements poses limitations on the applications for such technology. Therefore, alternative methods for verification and validation of FLCs needs to be explored. In this study, a novel approach using formal verification methods to ensure the stability of a FLC is proposed. Main research challenges include specification of requirements for a complex system, conversion of a traditional FLC to a piecewise polynomial representation, and using a formal verification tool in a nonlinear solution space. Using the proposed architecture, the Fuzzy Logic Controller was found to always generate negative feedback, but inconclusive for Lyapunov stability.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN32797 , SciTech 2017; Jan 09, 2017 - Jan 13, 2017; Grapevine, TX; United States
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    Methods and Apparatus for Deployable Swirl Vanes (2017)
    In:  CASI
    Details
    Publication Date: 2019-08-26
    Description: An aircraft control structure for drag management includes a nozzle structure configured to exhaust a swirling fluid stream. A plurality of swirl vanes are positioned within the nozzle structure, and an actuation subsystem is configured to cause the plurality of swirl vanes to move from a deployed state to a non-deployed state. In the non-deployed state, the plurality of swirl vanes are substantially flush with the inner surface of the nozzle structure. In the deployed state, the plurality of swirl vanes produce the swirling fluid stream.
    Keywords: Aircraft Stability and Control
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    Multi-Objective Flight Control for Drag Minimization and Load Alleviation of High-Aspect Ratio Flexible Wing Aircraft (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: As aircraft wings become much more flexible due to the use of light-weight composites material, adverse aerodynamics at off-design performance can result from changes in wing shapes due to aeroelastic deflections. Increased drag, hence increased fuel burn, is a potential consequence. Without means for aeroelastic compensation, the benefit of weight reduction from the use of light-weight material could be offset by less optimal aerodynamic performance at off-design flight conditions. Performance Adaptive Aeroelastic Wing (PAAW) technology can potentially address these technical challenges for future flexible wing transports. PAAW technology leverages multi-disciplinary solutions to maximize the aerodynamic performance payoff of future adaptive wing design, while addressing simultaneously operational constraints that can prevent the optimal aerodynamic performance from being realized. These operational constraints include reduced flutter margins, increased airframe responses to gust and maneuver loads, pilot handling qualities, and ride qualities. All of these constraints while seeking the optimal aerodynamic performance present themselves as a multi-objective flight control problem. The paper presents a multi-objective flight control approach based on a drag-cognizant optimal control method. A concept of virtual control, which was previously introduced, is implemented to address the pair-wise flap motion constraints imposed by the elastomer material. This method is shown to be able to satisfy the constraints. Real-time drag minimization control is considered to be an important consideration for PAAW technology. Drag minimization control has many technical challenges such as sensing and control. An initial outline of a real-time drag minimization control has already been developed and will be further investigated in the future. A simulation study of a multi-objective flight control for a flight path angle command with aeroelastic mode suppression and drag minimization demonstrates the effectiveness of the proposed solution. In-flight structural loads are also an important consideration. As wing flexibility increases, maneuver load and gust load responses can be significant and therefore can pose safety and flight control concerns. In this paper, we will extend the multi-objective flight control framework to include load alleviation control. The study will focus initially on maneuver load minimization control, and then subsequently will address gust load alleviation control in future work.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN38210 , AIAA SciTech Forum; Jan 09, 2017 - Jan 13, 2017; Grapevine, TX; United States
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    Aeroelastic Modeling of X-56A Stiff-Wing Configuration Flight Test Data (2017)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Aeroelastic stability and control derivatives for the X-56A Multi-Utility Technology Testbed (MUTT), in the stiff-wing configuration, were estimated from flight test data using the output-error method. Practical aspects of the analysis are discussed. The orthogonal phase-optimized multisine inputs provided excellent data information for aeroelastic modeling. Consistent parameter estimates were determined using output error in both the frequency and time domains. The frequency domain analysis converged faster and was less sensitive to starting values for the model parameters, which was useful for determining the aeroelastic model structure and obtaining starting values for the time domain analysis. Including a modal description of the structure from a finite element model reduced the complexity of the estimation problem and improved the modeling results. Effects of reducing the model order on the short period stability and control derivatives were investigated.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-24692 , AIAA SciTech 2017; Jan 09, 2017 - Jan 13, 2017; Dallas, TX; United States
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    [Editors' Choice] A pair of tablemates for aromatic benzene (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2016-09-09
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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    [This Week in Science] Coordinated scission of N–H or O–H bonds (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publication Date: 2016-11-11
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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    Dynamic Modeling from Flight Data with Unknown Time Skews (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A method for estimating dynamic model parameters from flight data with unknown time skews is described and demonstrated. The method combines data reconstruction, nonlinear optimization, and equation-error parameter estimation in the frequency domain to accurately estimate both dynamic model parameters and the relative time skews in the data. Data from a nonlinear F-16 aircraft simulation with realistic noise, instrumentation errors, and arbitrary time skews were used to demonstrate the approach. The approach was further evaluated using flight data from a subscale jet transport aircraft, where the measured data were known to have relative time skews. Comparison of modeling results obtained from time-skewed and time-synchronized data showed that the method accurately estimates both dynamic model parameters and relative time skew parameters from flight data with unknown time skews.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-21730 , 2016 AIAA SciTech Forum and Exposition; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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    NASA Super Pressure Balloon (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: NASA is in the process of qualifying the mid-size Super Pressure Balloon (SPB) to provide constant density altitude flight for science investigations at polar and mid-latitudes. The status of the development of the 18.8 million cubic foot SPB capable of carrying one-tonne of science to 110,000 feet, will be given. In addition, the operating considerations such as launch sites, flight safety considerations, and recovery will be discussed.
    Keywords: Aircraft Stability and Control
    Type: GSFC-E-DAA-TN32079 , 2016 Scientific Ballooning Technologies Workshop; May 09, 2016 - May 11, 2016; Minneapolis, MN; United States
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    Air STAR Beyond Visual Range UAS Description and Preliminary Test Results (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The NASA Airborne Subscale Transport Aircraft Research Unmanned Aerial System project's capabilities were expanded by updating the system design and concept of operations. The new remotely piloted airplane system design was flight tested to assess integrity and operational readiness of the design to perform flight research. The purpose of the system design is to improve aviation safety by providing a capability to validate, in high-risk conditions, technologies to prevent airplane loss of control. Two principal design requirements were to provide a high degree of reliability and that the new design provide a significant increase in test volume (relative to operations using the previous design). The motivation for increased test volume is to improve test efficiency and allow new test capabilities that were not possible with the previous design and concept of operations. Three successful test flights were conducted from runway 4-22 at NASA Goddard Space Flight Center's Wallops Flight Facility.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-23006 , 2016 AIAA SciTech Conference; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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    Benchmarking Model Variants in Development of a Hardware-in-the-Loop Simulation System (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Distributed engine control architecture presents a significant increase in complexity over traditional implementations when viewed from the perspective of system simulation and hardware design and test. Even if the overall function of the control scheme remains the same, the hardware implementation can have a significant effect on the overall system performance due to differences in the creation and flow of data between control elements. A Hardware-in-the-Loop (HIL) simulation system is under development at NASA Glenn Research Center that enables the exploration of these hardware dependent issues. The system is based on, but not limited to, the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k). This paper describes the step-by-step conversion from the self-contained baseline model to the hardware in the loop model, and the validation of each step. As the control model hardware fidelity was improved during HIL system development, benchmarking simulations were performed to verify that engine system performance characteristics remained the same. The results demonstrate the goal of the effort; the new HIL configurations have similar functionality and performance compared to the baseline C-MAPSS40k system.
    Keywords: Aircraft Stability and Control
    Type: GRC-E-DAA-TN28906 , AIAA SciTech 2016; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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    Toward n-Ship Computation of Trajectories for Shared Airspace (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper considers an approach for modelling transport aircraft trajectories that can facilitate their rapid evaluation and modification, either en route or in terminal control areas, with the goal of efficiently making use of airspace and runways by a large population of vehicles without pairwise violation of separation criteria.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-24516 , AIAA Aviation Technology, Integration, and Operations Conference; Jun 13, 2016 - Jun 17, 2016; Washington, DC; United States
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    Parameter Uncertainty for Aircraft Aerodynamic Modeling using Recursive Least Squares (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A real-time method was demonstrated for determining accurate uncertainty levels of stability and control derivatives estimated using recursive least squares and time-domain data. The method uses a recursive formulation of the residual autocorrelation to account for colored residuals, which are routinely encountered in aircraft parameter estimation and change the predicted uncertainties. Simulation data and flight test data for a subscale jet transport aircraft were used to demonstrate the approach. Results showed that the corrected uncertainties matched the observed scatter in the parameter estimates, and did so more accurately than conventional uncertainty estimates that assume white residuals. Only small differences were observed between batch estimates and recursive estimates at the end of the maneuver. It was also demonstrated that the autocorrelation could be reduced to a small number of lags to minimize computation and memory storage requirements without significantly degrading the accuracy of predicted uncertainty levels.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-21676 , AIAA 2016 SciTech Forum and Exposition; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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    Real-Time Global Nonlinear Aerodynamic Modeling for Learn-To-Fly (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Flight testing and modeling techniques were developed to accurately identify global nonlinear aerodynamic models for aircraft in real time. The techniques were developed and demonstrated during flight testing of a remotely-piloted subscale propeller-driven fixed-wing aircraft using flight test maneuvers designed to simulate a Learn-To-Fly scenario. Prediction testing was used to evaluate the quality of the global models identified in real time. The real-time global nonlinear aerodynamic modeling algorithm will be integrated and further tested with learning adaptive control and guidance for NASA Learn-To-Fly concept flight demonstrations.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-21688 , 2016 AIAA SciTech Conference; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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    Flight Analysis of an Autonomously Navigated Experimental Lander for High Altitude Recovery (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: First steps have been taken to qualify a family of parafoil systems capable of increasing the survivability and reusability of high-altitude balloon payloads. The research is motivated by the common risk facing balloon payloads where expensive flight hardware can often land in inaccessible areas that make them difficult or impossible to recover. The Autonomously Navigated Experimental Lander (ANGEL) flight test introduced a commercial Guided Parachute Aerial Delivery System (GPADS) to a previously untested environment at 108,000ft MSL to determine its high-altitude survivability and capabilities. Following release, ANGEL descended under a drogue until approximately 25,000ft, at which point the drogue was jettisoned and the main parachute was deployed, commencing navigation. Multiple data acquisition platforms were used to characterize the return-to-point technology performance and help determine its suitability for returning future scientific payloads ranging from 180 to 10,000lbs to safer and more convenient landing locations. This report describes the test vehicle design, and summarizes the captured sensor data. Various post-flight analyses are used to quantify the system's performance, gondola load data, and serve as a reference point for subsequent missions.
    Keywords: Aircraft Stability and Control
    Type: GRC-E-DAA-TN28393 , AIAA SciTech 2016; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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    Identification and Reconfigurable Control of Impaired Multi-Rotor Drones (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The paper presents an algorithm for control and safe landing of impaired multi-rotor drones when one or more motors fail simultaneously or in any sequence. It includes three main components: an identification block, a reconfigurable control block, and a decisions making block. The identification block monitors each motor load characteristics and the current drawn, based on which the failures are detected. The control block generates the required total thrust and three axis torques for the altitude, horizontal position and/or orientation control of the drone based on the time scale separation and nonlinear dynamic inversion. The horizontal displacement is controlled by modulating the roll and pitch angles. The decision making algorithm maps the total thrust and three torques into the individual motor thrusts based on the information provided by the identification block. The drone continues the mission execution as long as the number of functioning motors provide controllability of it. Otherwise, the controller is switched to the safe mode, which gives up the yaw control, commands a safe landing spot and descent rate while maintaining the horizontal attitude.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN24294 , AIAA Science and Technology Forum and Exposition (SciTech 2016); Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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    Effects of Different Heave Motion Components on Pilot Pitch Control Behavior (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The study described in this paper had two objectives. The first objective was to investigate if a different weighting of heave motion components decomposed at the center of gravity, allowing for a higher fidelity of individual components, would result in pilot manual pitch control behavior and performance closer to that observed with full aircraft motion. The second objective was to investigate if decomposing the heave components at the aircraft's instantaneous center of rotation rather than at the center of gravity could result in additional improvements in heave motion fidelity. Twenty-one general aviation pilots performed a pitch attitude control task in an experiment conducted on the Vertical Motion Simulator at NASA Ames under different hexapod motion conditions. The large motion capability of the Vertical Motion Simulator also allowed for a full aircraft motion condition, which served as a baseline. The controlled dynamics were of a transport category aircraft trimmed close to the stall point. When the ratio of center of gravity pitch heave to center of gravity heave increased in the hexapod motion conditions, pilot manual control behavior and performance became increasingly more similar to what is observed with full aircraft motion. Pilot visual and motion gains significantly increased, while the visual lead time constant decreased. The pilot visual and motion time delays remained approximately constant and decreased, respectively. The neuromuscular damping and frequency both decreased, with their values more similar to what is observed with real aircraft motion when there was an equal weighting of the heave of the center of gravity and heave due to rotations about the center of gravity. In terms of open- loop performance, the disturbance and target crossover frequency increased and decreased, respectively, and their corresponding phase margins remained constant and increased, respectively. The decomposition point of the heave components only had limited effects on pilot manual control behavior and performance.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN32614 , AIAA Aviation 2016 Conference; Jun 13, 2016 - Jun 17, 2016; Washington, DC; United States
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    Calculated Low-Speed Steady and Time-Dependent Aerodynamic Derivatives for Several Different Wings Using a Discrete Vortex Method (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Calculated numerical values for some aerodynamic terms and stability Derivatives for several different wings in unseparated inviscid incompressible flow were made using a discrete vortex method involving a limited number of horseshoe vortices. Both longitudinal and lateral-directional derivatives were calculated for steady conditions as well as for sinusoidal oscillatory motions. Variables included the number of vortices used and the rotation axis/moment center chordwise location. Frequencies considered were limited to the range of interest to vehicle dynamic stability (kb 〈.24 ). Comparisons of some calculated numerical results with experimental wind-tunnel measurements were in reasonable agreement in the low angle-of-attack range considering the differences existing between the mathematical representation and experimental wind-tunnel models tested. Of particular interest was the presence of induced drag for the oscillatory condition.
    Keywords: Aircraft Stability and Control
    Type: NASA/TM-2016-219349 , L-20759 , NF1676L-25593
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    A New Formulation of the Filter-Error Method for Aerodynamic Parameter Estimation in Turbulence (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A new formulation of the filter-error method for estimating aerodynamic parameters in nonlinear aircraft dynamic models during turbulence was developed and demonstrated. The approach uses an estimate of the measurement noise covariance to identify the model parameters, their uncertainties, and the process noise covariance, in a relaxation method analogous to the output-error method. Prior information on the model parameters and uncertainties can be supplied, and a post-estimation correction to the uncertainty was included to account for colored residuals not considered in the theory. No tuning parameters, needing adjustment by the analyst, are used in the estimation. The method was demonstrated in simulation using the NASA Generic Transport Model, then applied to the subscale T-2 jet-engine transport aircraft flight. Modeling results in different levels of turbulence were compared with results from time-domain output error and frequency- domain equation error methods to demonstrate the effectiveness of the approach.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-20186 , AIAA Atmospheric Flight Mechanics Conference; Jun 22, 2015 - Jun 26, 2015; Dallas,TX; United States
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    Piloted Simulator Evaluation of Maneuvering Envelope Information for Flight Crew Awareness (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The implementation and evaluation of an efficient method for estimating safe aircraft maneuvering envelopes are discussed. A Bayesian approach is used to produce a deterministic algorithm for estimating aerodynamic system parameters from existing noisy sensor measurements, which are then used to estimate the trim envelope through efficient high- fidelity model-based computations of attainable equilibrium sets. The safe maneuverability limitations are extended beyond the trim envelope through a robust reachability analysis derived from an optimal control formulation. The trim and maneuvering envelope limits are then conveyed to pilots through three axes on the primary flight display. To evaluate the new display features, commercial airline crews flew multiple challenging approach and landing scenarios in the full motion Advanced Concepts Flight Simulator at NASA Ames Research Center, as part of a larger research initiative to investigate the impact on the energy state awareness of the crew. Results show that the additional display features have the potential to significantly improve situational awareness of the flight crew.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN19341 , AIAA Infotech 2015; Jan 05, 2015 - Jan 09, 2015; Kissimmee, FL; United States
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    Flight Research: X-31A Enhanced Fighter Maneuverability and F-18 High Alpha Research Vehicle (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN25157 , South Korean Delegration; Jul 16, 2015; Edwards AFB California; United States
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    Rapid State Space Modeling Tool for Rectangular Wing Aeroservoelastic Studies (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: This report introduces a modeling and simulation tool for aeroservoelastic analysis of rectangular wings with trailing-edge control surfaces. The inputs to the code are planform design parameters such as wing span, aspect ratio, and number of control surfaces. Using this information, the generalized forces are computed using the doublet-lattice method. Using Roger's approximation, a rational function approximation is computed. The output, computed in a few seconds, is a state space aeroservoelastic model which can be used for analysis and control design. The tool is fully parameterized with default information so there is little required interaction with the model developer. All parameters can be easily modified if desired. The focus of this report is on tool presentation, verification, and validation. These processes are carried out in stages throughout the report. The rational function approximation is verified against computed generalized forces for a plate model. A model composed of finite element plates is compared to a modal analysis from commercial software and an independently conducted experimental ground vibration test analysis. Aeroservoelastic analysis is the ultimate goal of this tool, therefore, the flutter speed and frequency for a clamped plate are computed using damping-versus-velocity and frequency-versus-velocity analysis. The computational results are compared to a previously published computational analysis and wind-tunnel results for the same structure. A case study of a generic wing model with a single control surface is presented. Verification of the state space model is presented in comparison to damping-versus-velocity and frequency-versus-velocity analysis, including the analysis of the model in response to a 1-cos gust.
    Keywords: Aircraft Stability and Control
    Type: NASA/TM-2015-218875 , DFRC-E-DAA-TN25358
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    Active Structural Control for Aircraft Efficiency with the X-56A Aircraft (2015)
    In:  CASI
    Details
    Publication Date: 2019-08-13
    Description: The X-56A Multi-Utility Technology Testbed is an experimental aircraft designed to study active control of flexible structures. The vehicle is easily reconfigured to allow for testing of different configurations. The vehicle is being used to study new sensor, actuator, modeling and controls technologies. These new technologies will allow for lighter vehicles and new configurations that exceed the efficiency currently achievable. A description of the vehicle and the current research efforts that it enables are presented.
    Keywords: Aircraft Stability and Control
    Type: AFRC-E-DAA-TN27228 , 2015 IFAR Young Researcher Conference; Oct 04, 2015 - Oct 10, 2015; Moffett Field, CA; United States
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    Method and System for Weakening Shock Wave Strength at Leading Edge Surfaces of Vehicle in Supersonic Atmospheric Flight (2015)
    In:  CASI
    Details
    Publication Date: 2019-08-28
    Description: A method and system are provided to weaken shock wave strength at leading edge surfaces of a vehicle in atmospheric flight. One or more flight-related attribute sensed along a vehicle's outer mold line are used to control the injection of a non-heated, non-plasma-producing gas into a local external flowfield of the vehicle from at least one leading-edge surface location along the vehicle's outer mold line. Pressure and/or mass flow rate of the gas so-injected is adjusted in order to cause a Rankine-Hugoniot Jump Condition along the vehicle's outer mold line to be violated.
    Keywords: Aircraft Stability and Control
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    Establishing a Disruptive New Capability for NASA to Fly UAV's into Hazardous Conditions (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A 2015 NASA Aeronautics Mission "Seedling" Proposal is described for a Severe-Environment UAV (SE-UAV) that can perform in-situ measurements in hazardous atmospheric conditions like lightning, volcanic ash and radiation. Specifically, this paper describes the design of a proof-of-concept vehicle and measurement system that can survive lightning attachment during flight operations into thunderstorms. Elements from three NASA centers draw together for the SE-UAV concept. 1) The NASA KSC Genesis UAV was developed in collaboration with the DARPA Nimbus program to measure electric field and X-rays present within thunderstorms. 2) A novel NASA LaRC fiber-optic sensor uses Faraday-effect polarization rotation to measure total lightning electric current on an air vehicle fuselage. 3) NASA AFRC's state-of-the-art Fiber Optics and Systems Integration Laboratory is envisioned to transition the Faraday system to a compact, light-weight, all-fiber design. The SE-UAV will provide in-flight lightning electric-current return stroke and recoil leader data, and serve as a platform for development of emerging sensors and new missions into hazardous environments. NASA's Aeronautics and Science Missions are interested in a capability to perform in-situ volcanic plume measurements and long-endurance UAV operations in various weather conditions. (Figure 1 shows an artist concept of a SE-UAV flying near a volcano.) This paper concludes with an overview of the NASA Aeronautics Strategic Vision, Programs, and how a SE-UAV is envisioned to impact them. The SE-UAV concept leverages high-value legacy research products into a new capability for NASA to fly a pathfinder UAV into hazardous conditions, and is presented in the SPIE DSS venue to explore teaming, collaboration and advocacy opportunities outside NASA.
    Keywords: Aircraft Stability and Control
    Type: SPIE Paper 9468-28 , NF1676L-21134 , SPIE DSS 2015 - Defense and Security Meeting; Apr 20, 2015 - Apr 24, 2015; Baltimore, MD; United States
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    Effects of False Tilt Cues on the Training of Manual Roll Control Skills (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper describes a transfer-of-training study performed in the NASA Ames Vertica lMotion Simulator. The purpose of the study was to investigate the effect of false tilt cues on training and transfer of training of manual roll control skills. Of specific interest were the skills needed to control unstable roll dynamics of a mid-size transport aircraft close to the stall point. Nineteen general aviation pilots trained on a roll control task with one of three motion conditions: no motion, roll motion only, or reduced coordinated roll motion. All pilots transferred to full coordinated roll motion in the transfer session. A novel multimodal pilot model identification technique was successfully applied to characterize how pilots' use of visual and motion cues changed over the course of training and after transfer. Pilots who trained with uncoordinated roll motion had significantly higher performance during training and after transfer, even though they experienced the false tilt cues. Furthermore, pilot control behavior significantly changed during the two sessions, as indicated by increasing visual and motion gains, and decreasing lead time constants. Pilots training without motion showed higher learning rates after transfer to the full coordinated roll motion case.
    Keywords: Aircraft Stability and Control
    Type: AIAA Paper 2015-0655 , ARC-E-DAA-TN20112 , AIAA SciTech 2015; Jan 05, 2015 - Jan 09, 2015; Kissimmee, FL; United States
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    Predicting Time Series Outputs and Time-to-Failure for an Aircraft Controller Using Bayesian Modeling (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Safety of unmanned aerial systems (UAS) is paramount, but the large number of dynamically changing controller parameters makes it hard to determine if the system is currently stable, and the time before loss of control if not. We propose a hierarchical statistical model using Treed Gaussian Processes to predict (i) whether a flight will be stable (success) or become unstable (failure), (ii) the time-to-failure if unstable, and (iii) time series outputs for flight variables. We first classify the current flight input into success or failure types, and then use separate models for each class to predict the time-to-failure and time series outputs. As different inputs may cause failures at different times, we have to model variable length output curves. We use a basis representation for curves and learn the mappings from input to basis coefficients. We demonstrate the effectiveness of our prediction methods on a NASA neuro-adaptive flight control system.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN23968 , Society for Industrial and Applied Mathematics (SIAM) Conference on Control and Its Applications; Jul 08, 2015 - Jul 10, 2015; Paris; France
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    A Case Study on the Application of a Structured Experimental Method for Optimal Parameter Design of a Complex Control System (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: This report documents a case study on the application of Reliability Engineering techniques to achieve an optimal balance between performance and robustness by tuning the functional parameters of a complex non-linear control system. For complex systems with intricate and non-linear patterns of interaction between system components, analytical derivation of a mathematical model of system performance and robustness in terms of functional parameters may not be feasible or cost-effective. The demonstrated approach is simple, structured, effective, repeatable, and cost and time efficient. This general approach is suitable for a wide range of systems.
    Keywords: Aircraft Stability and Control
    Type: NASA/TM-2015-218795 , L-20574 , NF1676L-21781
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    Electronic Resource
    Electronic Resource
    Schwefel - Stickstoff - Fluorverbindungen VI. Über Thioisodithiazylfluorid S3N2F2 (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 298 (1959), S. 72-77 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: In addition to the formation of S4N4, greenish-yellow crystal sheets of S3N2F2 are deposited from a mixture containing SN2F2 and SNF at pressures form 600 to 700 mm Hg. S3N2F2 crystallizes in two polymorphic forms; the melting and decomposition points are 85 and 95 - 97° Cm, respectively; solubility in CCl4 at 20°C: 1.5 grs./100 grs. The observed formation of S3N2F2 is discussed in respect to the tendency of stable S—F-bond formation.
    Notes: Aus einem Gemisch von SN2F2 und SNF scheidet sich bei Drucken von 600 bis 700 Torr an der Wand des Reaktionskolbens ein gelber Beschlag ab, während gleichzeitig grüngelbe Kristallblättchen ins Innere des Kolbens wachsen. Bei letzteren handelt es sich um S3N2F2, das in zwei polymorphen Kristallarten auftritt. Fp. 85°C; Zers.-Pkt. 95-97°C. Löslichkeit in CCl4: 1,5 g/100 g bei 20°.Aus dem gelben Wandbeschlag wird durch Dekantieren mit Acetonitril S4N4 erhalten. Die Bildung von S3N2F2 wird diskutiert und festgestellt, daß die Tendenz zur Bildung stabiler S—F-Bindungen als Ursache für die Zersetzung von SN2F2 + SNF angesehen werden kann.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19592980111
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    Electronic Resource
    Electronic Resource
    Infrarotspektroskopische und röntgenographische Untersuchungen am Quecksilber(II)-äthylendiaminchlorid (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 298 (1959), S. 142-151 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The reaction between 1 mol mercuric chloride and 1 mol ethylenediamine (I) leads in aqueous and in diluted alcoholic solutions to a mixture of mercuric chloride and mercuric ethylenediamine chloride, Hg(NH2CH2CH2NH2)Cl2 (II). It is possible to get the compound (II) in pure state in absolute alcolholic solution. X-ray and infrared investigations give evidence for a chain-structure of (II) with (I) bounded in the trans-form.
    Notes: In wäßrigen und verdünnten alkoholischen Lösungen reagieren 1 Mol Quecksilber(II)-chlorid und 1 Mol Äthylendiamin unter Bildung unlöslicher Produkte, die aus Gemischen von Hg(NH2—CH2—CH2—NH2)Cl2 und HgCl2 bestehen. Wird die Reaktion unter Wasserausschluß in absolutem Alkohol ausgeführt, so entsteht reines Quecksilber(II)-äthylendiaminchlorid, Hg(en)Cl2 (en = Äthylendiamin). Durch die Diskussionen des Debyeogramms und des Infrarotspektrums der Verbindung können Ringstrukturen ausgeschlossen werden; es liegt eine Kettenstruktur mit trans-Stellung der XH2-Gruppen (X = N oder C) der Äthylendiamin-Molekel vor.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19592980305
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    Electronic Resource
    Electronic Resource
    Darstellung und thermische Zersetzung der Dichlorphosphorsäure H[PO2Cl2] (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 298 (1959), S. 152-163 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pure crystallizable dichlorophosphoric acid H[PO2Cl2] is prepared by reaction of dichlorophosphoric acid anhydride P2O3Cl4 with the calculated amount of water at temperatures below -30°C.When heated under reduced pressure (12 mm), and hydrogen chloride simultaneously is passed through, the dichlorophosphoric acid splits off water and is therefore again transformed into the dichlorophosphoric acid anhydride P2O3Cl4.Contrary to this the dichlorophosphoric acid decomposes, when heated under atmospheric pressure, mainly by splitting off HCl.
    Notes: Reine, kristallisierbare Dichlorphosphorsäure H[PO2Cl2] läßt sich durch Reaktion von Dichlorphosphorsäureanhydrid P2O3Cl4 mit der berechneten Menge Wasser bei Temperaturen unterhalb -30°C darstellen.Beim Erhitzen unter vermindertem Druck (12 mm) und gleichzeitigem Durchleiten von Chlorwasserstoff spaltet die Dichlorphosphorsäure Wasser ab und geht dadurch wieder in das Dichlorphosphorsäureanhydrid P2O3Cl4 über.Dagegen zersetzt sich die Dichlorphosphorsäure beim Erhitzen unter Atmosphärendruck vorwiegend unter HCl-Abspaltung.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19592980306
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  • 72
    Electronic Resource
    Electronic Resource
    Über Phosphornitrilfluoride (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 298 (1959), S. 193-193 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19592980309
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  • 73
    Electronic Resource
    Electronic Resource
    Über die Einwirkung der Halogenate auf Vanadin(III)-oxyd in wäßriger Lösung (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 298 (1959), S. 194-201 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Vanadium(III)oxide, V2O3, is autocatalytically oxidized to vanadium(V)oxide or vanadates(V) by acid or neutral solutions of alkali metal chlorates, bromates, iodates, and periodates. By perchlorate ions, V2O3 is converted to vanadium(IV) compounds. The influence of pH and buffer systems has been investigated. The velocity of oxidation decreases from periodate, bromate, iodate, chlorate to perchlorate. In alkaline solutions the reaction of iodates is greater than that of bromates.
    Notes: Vanadin(III)-oxyd, V2O3, wird sowohl in saurer als auch ursprünglich neutraler Lösung der Alkalichlorate, -bromate, -jodate und -perjodate zu Vanadin(VI)-oxyd bzw. Vanadat und bei der Einwirkung von Perchlorationen langsam zur Vanadin(IV)-stufe oxydiert. Die Reaktionen verlaufen offenbar autokatalytisch. Die Halogenate wirken auch dann oxydierend, wenn der Einfluß der bei den Reaktionen gebildeten Wasserstoffionen durch Zusatz von Natriumhydrogencarbonat oder Calciumcarbonat zum Reaktionsgemisch aufgehoben wird und sogar unter alkalischen Bedingungen, wenn auch langsamer als in ungepufferten Lösung. Die Halogenate werden allgemein zur Halogenidstufe reduziert mit Ausnahme von Perjodat, das, falls reichlich von ihm vorhanden ist, zu Jodat reduziert wird. Die Oxydationsgeschwindigkeit nimmt in der Reihenfolge: Perjodat 〉 Bromat 〉 Jodat 〉 Chlorat 〉 Perchlorat ab. In alkalischen Lösungen oxydieren die Jodate schneller als die Bromate.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19592980310
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    Electronic Resource
    Electronic Resource
    Spektroskopische Untersuchungen an Siliciumverbindungen. VIII. Die Schwingungsspektren einiger Tetramethyldisiloxane (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959), S. 78-86 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Raman and infrared spectra of compounds of the type X (CH3)2SiOSi(CH3)2X (X = H, OH, Cl, C6H5 are reported and the frequencies are assigned. The shift of the valence frequencies of the framework is briefly discussed. The approximate valence force constant of the SiOSi bond in HO(CH3)2SiOSi(CH3)2OH is calculated to 4,97 mdyn/Å.
    Notes: Die Raman- und IR-Spektren der Verbindungen X(CH3)2SiOSi(CH3)2X (X = H, OH, Cl und C6H5) werden mitgeteilt und die Frequenzen den einzelnen Schwingungsformen zugeordnet. Der Gang der Valenzfrequenzen des Gerüstes wird kurz diskutiert. Für das Tetramethyldioxydisiloxan wird die angenäherte Valenzkraftkonstante für die Siloxanbindung zu 4,97 mdyn/Å berechnet.
    Additional Material: 4 Ill.
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    Masthead (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959) 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19592990301
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    Zur Frage des Reaktionsmechanismus des HCOOH-Zerfalls an Ni-Oberflächen. „Über den Mechanismus des Ameisensäuredampf-Zerfalls am Nickel“ (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959), S. 151-152 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A mechanism of the decomposition of the formic acid on a surface of nickel is proposed.
    Notes: Es wird ein Mechanismus der genannten Reaktion angegeben.
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    Spektroskopische Untersuchungen an Siliciumverbindungen. IX. Über die Bindungsverhältnisse in der Siliciumchemie (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959), S. 138-150 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The bonds between silicium and elements of a great electronegativity are customary stronger than single bonds. This is shown by the valence force constants. The valence frequencies of substituted compounds indicate that strong electronegative substituends strengthen adjacent bonds. The mechanism of this strengthening is discussed.
    Notes: Die Valenzkraftkonstanten für Bindungen zwischen Silicium und stark elektronegativen Partnern zeigen, daß diese Bindungen in der Regel stärker als normale Einfachbindungen sind. Die Valenzfrequenzen in gemischt substituierten Verbindungen lassen erkennen, daß stark elektronegative Substituenten benachbarte Bindungen verstärken. Der Mechanismus dieser Bindungsverstärkungen wird diskutiert.
    Additional Material: 18 Tab.
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    Bleiverbindungen mit Apatitstruktur, insbesondere Blei-Jod- und Blei-Brom-Apatite (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 41-50 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The compounds Pb5(XO4)3Z (with X = P, As, V and Z = F, Cl, Br, J) have been prepared and investigated by X-ray analysis. With the exception of Pb5(PO4)3J, all compounds crystallize in apatite structure which is orthorhombically deformed in the case of Pb5(AsO4)3J.
    Notes: Es wird die Synthese von Bleiapatiten der Zusammensetzung Pb5(XO4)3Z [X = P, As, V und Z = F, Cl, Br, J] beschrieben. Röntgenaufnahmen ergeben in allen Fällen außer Pb5(PO4)3J die Apatitstruktur, im Falle des Pb5(AsO4)3J ist sie rhombisch deformiert. Einige Strukturdaten dieser Verbindungen werden mitgeteilt.
    Additional Material: 3 Ill.
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    Zur Kenntnis der Chemie der Metallcarbonyle in flüssigem Ammoniak. IV. Über Neue Substitutionsprodukte des Cr(CO)6 mit aromatischen Aminen (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 51-60 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: By interaction of alkali pentacarbonyl chromates(-II) with aromatic mono-, di-, and triamines at room temperature only pentacarbonyl amine chromium(0) compounds are formed. Wheras m- and p-phenylene diamine are linked with two and 1, 3, 5-triaminobenzene with three Cr(CO)5-groups, o-phenylene diamine forms a corresponding compound with only one Cr(CO)5-group. Unlike ethylene diamine or cyclohexane diamine(1,2) o-phenylene diamine does not give a tetracarbonyl chromium(0) compound.
    Notes: Bei der Umsetzung von Alkali-pentacarbonyl-chromaten(-II) mit wäßrigen Lösungen von aromatischen Mono-, Di- und Triaminen bei gewöhnlicher Temperatur erhält man stets Pentacarbonyl-amin-chrom(0)-verbindungen, die sich als echte Substitutions-produkte des Cr(CO)6 erweisen. Während m- und p-Phenylendiamin zwei und 1,3,5-Triaminobenzol drei Cr(CO)5-Gruppen zu binden vermögen, erhält man im Falle des o-Phenylendiamins eine entsprechende Verbindung mit nur einer Cr(CO)5-Gruppe. Insbesondere entsteht bei letzterem - im Gegensatz zum Äthylendiamin - keine Tetracarbonyl-chrom(0)-verbindung. Eine solche bildet sich hingegen, wenn man an Stelle des o-Phenylendiamins das hydrierte o-Phenylendiamin, also Cyclohexandiamin(1,2), zur Reaktion bringt.
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    URL: http://dx.doi.org/10.1002/zaac.19593000105
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    Beiträge zur Chemie der Elemente Niob und Tantal. XXI. Präparative Untersuchungen mit niederen Niobchloriden (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 1-32 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The system niobium-chlorine has been investigated.The formation of niobiumtrichloride, with a composition range from NbCl2.67 to NbCl3.1, has been studied by thermal decomposition of niobium tetrachloride, reduction of NbCl5 with hydrogen, and the chemical transport reaction: \documentclass{article}\pagestyle{empty}\begin{document}$${\rm NbcL}_{\rm X} {\rm f + (4 - x)NbCl}_{\rm 5} {\rm g = (5 - x)NbCl}_{\rm 4} {\rm g}$$\end{document}.The thermal and chemical properties of the niobiumtrichloride phase are described.Niobium(II)-chloride which is a stoichiometric compound is formed in the reactions Nb+NbCla2.67, NbSNbCI5, and NbCl5+H. There is no evidence for the existence of niobium (I)-chloride.
    Notes: Das Niobtrichlorid besitzt einen großen Homogenitätsbereich. Die Phasengrenzen liegen bei den Zusammensetzungen NbCl3,1 und NbCl2,67. Diese Grenzzusammensetzungen fallen schon beim thermischen Abbau des Niobtetrachlorids und bei der Reduktion von NbCl5 mit H2 auf. Weiteren Aufschluß geben Experimente, bei denen die Trichloridphase NbClx durch eine chemische Transportreaktion \documentclass{article}\pagestyle{empty}\begin{document}$${\rm NbcL}_{\rm X} {\rm f + (4 - x)NbCl}_{\rm 5} {\rm g = (5 - x)NbCl}_{\rm 4} {\rm g}$$\end{document} als Gleichgewichtsbodenkörper gewonnen wird. Die Zusammensetzung der Trichloridphase hängt in der zu fordernden Weise vom NbCl5-Druck ab. Aus Pulverdiagrammen und aus der Farbe der Trichlorid-Präparate läßt sich ebenfalls die Breite der Trichloridphase und auch die Zusammensetzung eines im homogenen Gebiet liegenden Präparats ableiten.Angaben über das Niobtrichlorid hinsichtlich seines thermischen und chemischen Verhaltens werden zusammengestellt.Niob(II)-chlorid wird aus Nb + NbCl2,67 gewonnen. Auch beim Erhitzen von Nb im NbCl5-Argon-Strom und bei der Reduktion von NbCl5 mit H2 ist die NbCl2-Bildung nachweisbar. NbCl2 besitzt keine erhebliche Phasenbreite. Das chemische und thermische Verhalten des NbCl2 werden studiert.Das metallische Niob löst keine nachweisbaren Cl-Mengen. Ein Niob(I)-chlorid wurde nicht gefunden.Zusammenfassend werden die Phasenverhältnisse im System Niob-Chlor dargestellt und weitere Probleme der Trichloridphase erörtert.Das letzte Kapitel bringt Analysenverfahren.
    Additional Material: 16 Ill.
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    Herstellung und Eigenschaften der Ternären Nitride von Vanadin, Niob und Tantal der Zusammensetzung Li7MeN4 (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 61-71 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The compound Li7VN4 containing vanadium(V) has been prepared by heating Li3N and VN in nitrogen atmosphere to a temperature of 680 °C. Li7VN4 crystallizes in an superstructure of fluorite lattice (space group T4d with a = 9.604 Å).Similarly, the compounds Li7NbN4 and Li7 TaN4 have been synthesized.
    Notes: 1. Durch Erhitzen von Li3N und VN in einer Stickstoffatmosphäre auf 680 °C wurde die Verbindung Li7VN4 hergestellt. Die Oxydationsstufe 5 des Vanadins wurde mit drei verschiedenen Methoden bestimmt. Die ternäre Verbindung ist thermisch beständiger als die zwei binären Nitride. Li7VN4 kristallisiert in einer Überstruktur des Flußspatgitters in der Raumgruppe T4d mit a = 9,604 Å. Ein ternäres Nitrid niedrigerer Oxydationsstufe konnte nicht hergestellt werden.2. Entsprechende Versuche führten zu den Verbindungen Li7NbN4 und Li7TaN4; diese Verbindungen sind chemisch und thermisch etwas stabiler als die Vanadinverbindung.
    Additional Material: 3 Ill.
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    Über Halogenide des dreiwertigen Titans (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959), S. 213-226 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A technical alteration of the TiCl3-preparation according to SHERFEY is described.The phase diagrams of the systems NaCl/TiCl3, KCl/TiCl3 and KBr/TiBr3 were investigated by thermal analysis. There exist the compounds: Na3TiCl6 (incongruent m. p. = 553° C), K3TiCl6 (m. p. = 783° C), K2TiCl5 (incongruent m. p. = 605° C), K3TiBr6 (m. p. = 662° C). The results were confirmed by microscopic and X-rax methods.In the NaCl- and KCl-rich melts exists the complex [TiCl6]3- probably.
    Notes: Eine technische Abänderung der TiCl3-Darstellung nach SHERFEY wird mitgeteilt.Die Untersuchung der Systeme NaCl/TiCl3, KCl/TiCl3 und KBr/TiBr3 mit Hilfe der Differential-Thermoanalyse ergab folgendes: Im System NaCl/TiCl3 existiert die Verbindung Na3TiCl6. Sie schmilzt inkongruent bei 553° C. Das Zustandsdiagramm KCl/TiCl3 zeigt die Verbindungen K3TiCl6 (Schmp. = 783° C) und K2TiCl5 an, wobei die letztere bei 605° C inkongruent schmilzt. Im System KBr/TiBr3 tritt die bei 662° C kongruent schmelzende Verbindung K3TiBr6 auf.Das Ergebnis der thermischen Analyse wird durch mikroskopische und röntgenographische Untersuchungen gesichert.Die Berechnung der Liquiduskurve auf der NaCl- bzw. KCl-reichen Seite der Zustandsdiagramme legt nahe, die Existenz von [TiCl6]3--Ionen in der Schmelze anzunehmen.
    Additional Material: 7 Ill.
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    Masthead (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959) 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19592990501
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    Zur Kenntnis des Verhaltens von Nichtmetallchalkogeniden gegenüber flüssigem Ammoniak. III. Das Verhalten von Tetraphosphor-heptasulfid gegenüber flüssigem Ammoniak (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959), S. 241-251 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Tetraphosphorus-heptasulfide, P4S7, undergoes disproportionation in liquid ammonia at a temperature of -33° C according to the equation mentioned in „Inhaltsübersicht“.Tetraphosphorus-heptasulfide, P4S7, undergoes disproportionation in liquid ammonia at a temperature of -33° C according to the equation mentioned in „Inhalts-übersicht“.From the reaction products, the properties of which are described there is evidence for the structure of P4S7, determined by X-ray diffraction(4). The trimer orange-coloured [P3S3(NH)4]4-anion is supposed to have a cyclic structure.The thermal decomposition of (NH4)3[PS4] and (NH4)2[PS3NH2], yielding P4N5, is discussed.
    Notes: Während die beiden niederen Phosphorsulfide(2) P4S3 und P4S5 mit flüssigem Ammoniak bei -33° unter Bildung von Ammoniumverbindungen mit vier P-atomen in der Molekel reagieren und P4S10(3) einfach gebaute Thiophosphate bildet, unterliegt Tetraphosphor-heptasulfid in diesem Medium gemäß 2P4S7 + 17 NH3 → (NH4)3[PS4] + 2 (NH4)2[PS3NH2] + (NH4)3[P3S3(NH)3] + NH4[P2SN] der Disproportionierung.Der obige Reaktionsverlauf läßt sich einerseits durch quantitative Erfassung der sich in ihrer Löslichkeit unterscheidenden Thiophosphate (NH4)3[PS4] und (NH4)2[PS3NH2], andererseits durch Isolierung der Verbindung [P3S3(NH)3], in der der Phosphor die Oxydationszahl +III einnimmt, nachweisen. Die experimentellen Ergebnisse lassen sich aus der für das P4S7 röntgenographisch nachgewiesenen Struktur(4) ableiten.Die Eigenschaften der erhaltenen Verbindungen werden beschrieben und die Ergebnisse des thermischen Abbaus von (NH4)3[PS4] und (NH4)2[PS3NH2], der in beiden Fällen schließlich zu P3N5 führt, diskutiert.Dem trimeren orangefarbenen Thio-imidophosphit-anion [P3S3(NH)3]3- wird ringförmige Struktur zugeschrieben.
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    Magnetochemische Untersuchungen im System FeO1 + x · MgO (O 〈x〈 0,5) (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959), S. 271-280 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The magnetic susceptibility of FeO1+x · 0,925 MgO (0 〈 x 〈 0,5) at 700, 750, 800, 850 and 900° C has been measured. The results are compared with values calculated under certain conditions and with the magnetic susceptibility of the system Fe—O, received in previous investigations.The isotherms of the susceptibility of magnesiowüstite (FeO1+y · 0,925 MgO) and wüstite (FeO1+y) allow to make some conclusions of the structure of the magnesiowüstite phase. It seems very probable that the ions Fe3+ both in magnesiowüstite and in wüstite occur in the form of accumulations. This „submicroheterogenity“ does not mean that magnesiowüstite from the point of view of thermodynamics consists of two solid phases.The homogeneity range of magnesiowüstite phase spreads at 700° C from FeO1,04 · 0,925 MgO to FeO1,09 · 0,925 MgO and at 900° C about FeO1,015 · 0,925 MgO to about FeO1,11 · 0,925 MgO.
    Notes: Im System FeO1+x · 0,925 MgO (0 〈 x 〈 0,5) wurde für 15 Präparate die magnetische Suszeptibilität bei 700°, 750°, 800°, 850° und 900°C gemessen. Die Ergebnisse werden mit den unter bestimmten Voraussetzungen berechneten Suszeptibilitäten und mit den für das System Fe—O früher erhaltenen experimentellen Werten verglichen. Aus dem Verlauf der Suszeptibilitätsisothermen in den Homogenitätsbereichen der „Magnesiowüstit“-Phase (feste Lösungen von FeO1+y und 0,925 MgO) und der Wüstitphase (FeO1+y) konnten gewisse Schlüsse in bezug auf die Struktur der „Magnesiowüstit“-Phase gezogen werden. Es ist wahrscheinlich, daß die Fe3+-Ionen im Magnesiowüstit, ähnlich wie im Wüstit, in Form von Ansammlungen vorhanden sind. Diese „Submikroinhomogenität“ bedeutet nicht, daß Magnesiowüstit im thermodynamischen Sinne aus zwei festen Phasen besteht.Der Homogenitätsbereich der Magnesiowüstitphase erstreckt sich bei 700° C von FeO1,04 · 0,925 MgO bis FeO1,09 ·0,925 MgO und bei 900° C von FeO1,015 · 0,925 MgO bis ungefähr FeO1,11 · 0,925 MgO.Das Curie-Weiss-Gesetz wird von den im Homogenitätsbereich der Magnesiowüstitphase liegenden Präparaten befolgt.Die Abhängigkeit der magnetischen Suszeptibilität von der Zusammensetzung bei höheren Sauerstoffgehalten (x 〉 1,1) ist infolge des Auftretens zweier fester Phasen veränderlicher Zusammensetzung kompliziert.
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    Schwermetallkomplexe mit Thiopicolinsäure-anilidBald nach dem Einreichen des Manuskriptes der vorliegenden Arbeit erschien über den gleichen Gegenstand eine Veröffentlichung von F. Lions u. K. F. Martin, J. Amer. chem. Soc. 80, 1591 (1958). Auf die Ergebnisse der australischen Autoren wollen wir in unserer zweiten diesbezüglichen Publikation eingehen. (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 299 (1959), S. 281-291 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Thiopicolinic acid anilide reacts with ions of heavy metals to form inner complex salts. Complexes of 12 metals have been prepared. The coordination compound with Fe(II)-ions is deep violet.
    Notes: Thiopicolinsäure-anilid fungiert gegenüber Schwermetallionen, besonders azo- und chalkophilen, als Innerkomplexligand wie als Neutralligand(1). Das Anilid wird als Anion der tautomeren Iminothiol-Form von dem betreffenden Metallion innerkomplex koordiniert, wobei je nach Ladungs- und charakteristischer Koordinationszahl des Zentrums entweder ladungslose oder Acido-Innerkomplexe entstehen. Analytisch definierte Komplexe wurden von 12 verschiedenen Metallen gewonnen, wobei die sehr intensive Violettfarbe der Eisen(II)-komplexe hervorzuheben ist.
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    Ultrarotspektren von Tellursäuren, Telluraten und Antimonaten (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 301 (1959), S. 161-170 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The infrared spectra of some telluric acids, tellurates and antimonates are measured. The constitution of these compounds is discussed.
    Notes: Es werden die Ultrarotspektren der Verbindungen H6TeO6, (H2TeO4)x, Na2H4TeO6, K2H4TeO6 · 3 H2O, Na[Sb(OH)6], KSbO3 · 2,2 H2O, Na2HSb3O9 · 4 H2O, K2HSb3O9 · 5 H2O, NaSbO3 und KSbO3 im Bereich 400-4000 cm-1 angegeben und ausgedeutet. Die Konstitution dieser Verbindungen wird diskutiert.
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    Die Schwingungsspektren von verschiedenen Cyanaten des Siliciums (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 194-204 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: From infrared spectra in the NaCl-region and Raman spectras of several cyanates of silicon (see „Inhaltsübersicht°“), the isocyanate structure for all these compounds has been demonstrated. There is a small multiple bond character of Si-N-bonds.
    Notes: Es wurden die Infrarot-Spektren im NaCl-Bereich und die Raman-Spektren von (CH3)3Si(NCO), (CH3)2Si(NCO)2, CH3Si(NCO)4, Si(NCO)4 und Si2O(NCO)6 aufgenommen und eine Zuordnung zu den Grundschwingungen dieser Molekel vorgenommen. Für alle Verbindungen konnte die Isocyanatstruktur spektroskopisch nachgewiesen werden, auch für die in der Literatur mit normaler Cyanatstruktur beschriebene Verbindung. Bei dieser handelt es sich um ein Gemisch von Si(NCO)4 + Si2O(NCO)6. Weiterhin ergab sich aus den Spektren der Isocyanate, daß die Si-N-Bindungen einen geringen Mehrfachbindungsanteil haben.
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    Farbe und Konstitution bei anorganischen Feststoffen. II. Die Lichtabsorption des zweiwertigen Nickels in oxydischen Koordinationsgittern (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 159-174 
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    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The influence of coordination number, lattice expansion, and decreasing degree of symmetry or distortion of the coordination polyhedron on the light absorption of Ni2+-ions in various oxides (see „Inhaltsübersicht°“) have been studied by spectrophotometric determination of powder remission.As in the case of Co(II)-containing oxides, the main absorption band is shifted toward the UV-region by raising the coordination number from 4 to 6. Displacement toward the red sometimes occurs on lattice expansion.Stronger shiftings to the red and high intensities of absorption have been observed when the decrease of point symmetry of coordination polyhedron is accompanied by stronger distortion.The ranges of homogeneity in the system Zn2SiO4/Ni2SiO4 have been determined spectrometrically.
    Notes: Durch spektralphotometrische Bestimmung der Remission von Pulvern wurde die Abhängigkeit der Lichtabsorption des Ni2+ von folgenden Faktoren untersucht: 1. Koordinationszahl (Ni0,1Mg0,9Al2O4, KZ = 4, Ni0,1Mg0,9O, KZ = 6) 2. Gitterdehung (Ni0,1Mg0,9Al2O4 → Ni0,1Mg0,9Ga2O4), (Ni0,1Mg0,9O → Ni0,01Mg0,69Zn0,3O), (Ni0,1Mg0,9TiO3 → Ni0,1Cd0,9TiO3) 3. Symmetrieerniedrigung bzw. Verzerrung des Koordinationspolyeders (Ni0,1Zn1,9SiO4, Ni0,01Zn0,99O), (Ni0,25Mg1.75SiO4, Ni0,1Mg0,9TiO3). Wie im Fall des Co2+ bewirkt hier die Erhöhung der Koordinationszahl von 4 auf 6 bei einer Eigensymmetrie des Koordinationspolyeders Td bzw. Oh eine UV-Verschiebung der Hauptabsorptionsbanden. Eine Gitterdehnung kann, insbesondere bei einfachen Gittern, eine Rotverschiebung bewirken. Eine Erniedrigung der Punktsymmetrie des Koordinationspolyeders hat nur dann eine stärkere Rotverschiebung und Erhöhung der Absorptionsintensität zur Folge, wenn damit gleichzeitig eine stärkere Verzerrung des Koordinationsoktaeders verbunden ist. Das System Zn2SiO4/Ni2SiO4 wurde spektralphotometrisch untersucht und die Grenzen der Homogenitätsgebiete aus dem Vergleich der Spektren ermittelt.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593000307
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    Über Schwermetallamide. IX. Hydroxokobalt(III)-amide (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 175-193 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Two isomeric hydroxy-cobalt(III)-amides, I and II, of the composition [Co(NH2)2OH]n have been prepared by interaction of KNH2 with [Co(NH3)5OH](NO3)2 and [Co2(NH3)8(OH)2]X4 (X = NO3- or SCN-), respectively, in liquid ammonia. The reactions of the amorphous amides, the structures of which are discussed, with a surplus of KNH2 and NH4NO3 in liquid ammonia and the thermal decomposition of II have been studied.The reaction between [Co(NH3)6](NO3)3 and KNH2 yields {[Co2(NH2)5NH3]n(NO3)n}.
    Notes: Durch Umsetzung von [Co(NH3)5(OH)](NO3)2 (I) und [Co2(OH)2(NH3)8]X4 (II) (X = NO3 oder SCN) mit KNH2 in flüssigem NH3 wurden zwei strukturisomere Mono-hydroxokobalt(III)-amide {Co(NH2)2OH}n (III bzw. IV) als unlösliche, amorphe Niederschläge erhalten. Das aus II gewonnene m̈-Monohydroxokobalt-(III)-amid (IV) besitzt noch die Di-m̈-hydroxogruppierung, sofern die Fällung bei tiefen Temperaturen (-20° C) erfolgt. Beide Verbindungen III und IV sind als Derivate des Kobalt(III)-amids zu betrachten und sind wie dieses mehr oder weniger hochpolymer. Unter Berücksichtigung des Strukturprinzips ist III als poly-m̈-Hydroxo-di-m̈-amino-kobalt(III) und IV als poly-[Di-m̈-hydroxo-m̈-amino-kobalt-tri-m̈-amino-kobalt(III)] zu bezeichnen. Der aus I resultierende Bodenkörper (III) reagiert mit NH4NO3 in flüssigem NH3 unter additiver Salzbildung zu {[Co2(OH)2NH2(NH3) 6]n(NO3)3n} (V), einem amorphen Nitrat, mit polymerem Kation, das noch alle OH-Gruppen enthält. IV reagiert ebenfalls mit NH4NO3 unter additiver Salzbildung, jedoch unter Eliminierung der Hälfte aller OH-Gruppen zu {[Co2(OH)(NH2)2(NH3)6]n(NO3)3n} (VIII). Mit KNH2 erfolgt ein Austausch von OH gegen NH2 sowohl in III als auch in IV unter Bildung von KOH. Bei der Reaktion von II mit KNH2 konnte ein definiertes Zwischenprodukt {[Co2(OH)2(NH2)3(NH3)2]n(NO3)n} (VI) gefaßt werden. Ein analoges; um 1 NH3 ärmeres Zwischenprodukt {[Co2(NH2)5(NH3)]n(NO3)n} (VII) - die OH-Gruppen sind durch NH2 ersetzt - entsteht auch bei der Reaktion von [Co(NH3)6](NO3)3 mit KNH2 in flüssigem NH3. Der thermische Abbau von IV führt unter NH3- und N2-Abspaltung schließlich zu CoO. Eine Wasserabspaltung wurde hierbei nicht beobachtet.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593000308
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    Über ein Siliciumphosphid Si2P (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 205-209 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The compound Si2P is formed at 450 °C from SiH4 and PH3, if the starting gas mixtures are containing SiH4 and PH3 in the ratio of 1 : 1 or 1 : 2. Si2P is a blue black non-crystalline substance. At 600 °C Si2P decomposes into Si and SiP as recognized from X-ray diagrams and IR-spectra. SiP formed from Si2P is identical with that prepared by Biltz1) from its elements.
    Notes: Aus SiH4 und PH3 bildet sich um 450 °C die Verbindung Si2P, wenn man von Gasmischungen SiH4:PH3 = 1 : 1 oder 1 : 2 ausgeht. Si2P ist ein blauschwarzes, röntgenamorphes Produkt. Um 600 °C zerfällt es in Si und SiP, wie aus den Röntgendiagrammen und den IR-Aufnahmen zu erkennen ist. Das aus dem Si2P entstehende SiP ist mit dem von Biltz1) aus den Elementen dargestellten SiP identisch.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593000310
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    Masthead (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959) 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19593000501
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    Spektroskopische Untersuchungen an Siliciumverbindungen. X. Schwingungsspektren und Struktur des Tetramethyl-cyclo-disilthians und des Hexamethyl-cyclo-trisilthians (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 210-220 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Raman and infrared spectra of [(CH3)2SiS]2 and [(CH3)2SiS]3 are reported and the frequencies are assigned as far as possible. [(CH3)2SiS]2 has the symmetrie D2h with a planar ring. The ring of [(CH3)2SiS]3 is puckered. The most probable symmetrie is here Cs (cis structure). The correlation of the SiXSi angle and the ring structure of siloxanes, silazanes and silthianes is discussed.
    Notes: Die Raman- und IR-Spektren des [(CH3)2SiS]2 und [(CH3)2SiS]3 werden mitgeteilt und die Frequenzen soweit wie möglich den einzelnen Schwingungsformen zugeordnet. Für das [(CH3)2SiS]2 ergibt sich eine ebene Ringstruktur nach D2h. Der Ring des [(CH3)2SiS]3 ist gewellt und hat höchstwahrscheinlich Cis-(Wannen-)Struktur, Punktgruppe Cs. Der Zusammenhang zwischen SiXSi-Winkel und Ringstruktur der Siloxane, Silazane und Silthiane wird diskutiert.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593000311
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    Das Verhalten von Amidophosphaten beim Erhitzen (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 221-224 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mixtures of amides of imidophosphoric acids with the composition PnOn(NH)n-1 · (NH2)n+2 are formed from OP(NH2)3 by heating at 100° C. - NaPO2)2 respectively Na2PO3NH2 looses all nitrogen by heating in the air at 900° resp. 1000° C and forms glassy (NaPO3)x resp. Na4P2O7.
    Notes: Amidophosphate werden beim Erhitzen infolge intermolekularer Abspaltung von Ammoniak zu Imidopolyphosphaten kondensiert. Aus Phosphoroxytriamid entstehen bei etwa 100° Gemische von Imidophosphorsäureamiden der Formel PnOn(NH)n-1(NH2)n+2 mit n = 2…5. Naturiumdiamidophosphat bzw. Natriummonoamidophosphat geben beim Erhitzen an der Luft auf 900° bzw. 1000° den gesamten Stickstoff ab und gehen in glasiges Natriumpolyphosphat (NaPO3)x bzw. Natriumdiphosphat über.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/zaac.19593000312
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    Eine Abgekürzte Schreibweise für Phosphorsäuren niederer Oxydationszahl Vorbemerkung zu den folgenden Mitteilungen (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 225-228 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: An abbreviated nomenclature is proposed for acids of phosphorus with lower oxydation number.
    Notes: Es wird eine abgekürzte Bezeichnungsweise für Phosphorsäuren niederer Oxydationszahl vorgeschlagen.
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    URL: http://dx.doi.org/10.1002/zaac.19593000502
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    Über Phosphorsäuren niederer Oxydationszahl. II. Über die \documentclass{article}\pagestyle{empty}\begin{document}${\rm (- P -)}_{\rm 6}$\end{document}-Ringsäure (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 237-249 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Red phosphorus suspended in alkali hydroxyde solutions reacts with hypohalogenites under formation of salts of an acid \documentclass{article}\pagestyle{empty}\begin{document}${\rm (- P -)}_{\rm 6}$\end{document}. The oxidation number of phosphorus in this compound is 3+. The phosphorus atoms are linked together by P - P bonds. The compound has a ring structure.
    Notes: In Alkalihydroxydlösungen suspendierter roter Phosphor reagiert mit Hypohalogeniten unter Bildung von Salzen einer \documentclass{article}\pagestyle{empty}\begin{document}${\rm (- P -)}_{\rm 6}$\end{document}-Ringsäure. Die Oxydationszahl des Phosphors in der Verbindung ist 3+; die Phosphoratome sind über P - P-Bindungen miteinander verknüpft. Die Verbindung hat Ringstruktur.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593000504
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    Über Phosphorsäuren niederer Oxydationszahl. III. Über die \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 3} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}Säure (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 250-260 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The preparation of salts of an acid of phosphorus in which 3 phosphorus atoms are linked together in a straight chain is described. The acid is prepared from oxidates of the acid \documentclass{article}\pagestyle{empty}\begin{document}${\rm (} - \mathop {\rm P}\limits^{\rm 3} -)_6$\end{document}, from oxidates of red phosphorus and from hydrolyzates of phosphorus tribromide.
    Notes: Die Herstellung von Salzen einer Säure des Phosphors, in der 3 Phosphor-Atome linear miteinander verbunden sind, aus Oxydaten der \documentclass{article}\pagestyle{empty}\begin{document}${\rm (} - \mathop {\rm P}\limits^{\rm 3} -)_6$\end{document}-Ringsäure, aus Oxydaten des roten Phosphors und aus Hydrolysaten des Phosphortribromids wird beschrieben.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593000505
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    Über Phosphorsäuren niederer Oxydationszahl. I. Über Oxydation und Hydrolyse der \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 2} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure und der \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 300 (1959), S. 229-236 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-acid is stable even towards 80% alkali hydroxide at 200°C. It is transformed to orthophosphate in molten anhydrous alkali hydroxide. The \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 2} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-acid is also very stable towards alkali hydroxide. Under rigorous conditions it is oxidized to \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-acid with yields up to 85% of theory under formation of hydrogen. High yields of \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-acid can also be obtained by reacting iodine with \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 2} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-acid in mineral acid solution. Copper catalyzed oxidation of \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-acid by hypobromite in alkaline solution leads to mixtures of ortho- and pyrophosphate.
    Notes: Die \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure ist sogar gegen 80proz. Alkalihydroxyd bei 200°C beständig, erst schmelzendes wasserfreies Alkalihydroxyd verwandelt zu Orthophosphat. Auch die \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 2} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure ist gegen Alkalihydroxyd sehr beständig; bei verschärften Bedingungen wird sie mit Ausbeuten bis zu 85% unter Wasserstoffentwicklung zur \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure oxydiert. Auch bei der Einwirkung von Jod auf die \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 2} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure in mineralsaurer Lösung können hohe Ausbeuten der \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure erhalten werden. Die durch Kupfer katalysierte Oxydation der \documentclass{article}\pagestyle{empty}\begin{document}$\mathop {\rm P}\limits^{\rm 4} {\rm - }\mathop {\rm P}\limits^{\rm 4}$\end{document}-Säure in alkalischer Lösung durch Hypobromit führt zu Gemischen von Ortho- und Pyrophosphat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19593000503
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    Über Peroxyantimonate (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 301 (1959), S. 316-322 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Solutions of antimonates give with H2O2 peroxy-antimonates. These are amorphous, polymeric, insoluble substances. The approximate composition of some of these compounds is KSbO4 · 1,7 H2O, NaSbO4 · 2 H2O, KSbO4 · 1,8 H2O2 and K2HSb3O12 · 3,5 H2O. The constitution of the peroxy-antimonates is discussed with help of their infrared spectra.
    Notes: Aus Lösungen von Kaliumantimonat entstehen mit H2O2 Peroxyantimonate. Diese sind amorphe, schwer lösliche, polymere Substanzen. Isoliert wurden unter anderem Verbindungen der annähernden Zusammensetzung KSbO4 · 1,7 H2O NaSbO4 · 2 H2O, KSbO4 v 1,8 H2O2 und K2HSb3O12 · 3,5 H2O. Die Konstitution der Peroxyantimonate wird an Hand ihrer Ultrarotspektren diskutiert.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593010514
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    Über die Hydroxylgruppen an der Oberfläche des Amorphen Siliciumdioxyds „Aerosil“ und ihre Reaktionen (1959)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 301 (1959), S. 326-335 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of surface hydroxyl groups have been investigated with finely divided amorphous silica (Aerosil). The hydroxyl groups react with calcium hydroxide; esters are formed by reaction with alcohols and diazomethane. Heating with thionyl chloride leads to substitution by chlorine. This reaction is especially suited for the quantitative determination of hydroxyl groups bound to silica surfaces.With lithium phenyl, chlorine bonded to surface silicon atoms can be substituted by phenyl groups.Quantitative determinations show that for Aerosil the number of surface hydroxyl groups is lower than the maximum amount estimated for silica surfaces; their surface concentration varied for different batches.
    Notes: An Aerosil, einem feinteiligen amorphen Siliciumdioxyd-Präparat der Degussa, wurden Umsetzungen mit den an der Oberfläche gebundenen Hydroxylgruppen durchgeführt. Die Hydroxylgruppen reagieren mit Calciumhydroxyd; mit Alkoholen und mit Diazomethan lassen sie sich verestern. Bei der Einwirkung von Thionylchlorid werden sie durch Chlor ersetzt. Diese Reaktion ist zur quantitativen Bestimmung der an Siliciumdioxyd-Oberflächen gebundenen Hydroxylgruppen besonders gut geeignet.Bei der Umsetzung mit Lithiumphenyl wird das am Silicium gebundene Chlor seinerseits durch Phenylgruppen ersetzt.Die quantitative Verfolgung der Reaktionen ergab, daß das Aerosil nicht die maximal mögliche Zahl oberflächenständiger Hydroxylgruppen besitzt. Ihre Menge pro Flächeneinheit ist vom jeweils gelieferten Muster abhängig.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/zaac.19593010516
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