ALBERT

Beschreibung: To prevent an overheating of the workpiece material and to increase the productivity in hot aluminum extrusion, the application of extrusion dies with conformal cooling channels manufactured additively by selective laser melting is known. Since, to date, the additive manufacturing processes are often accompanied with higher manufacturing time and costs in comparison to conventional subtractive methods, a new concept for a hybrid extrusion die is presented. Here, the large volume but geometrically simple die part, the die bridge, is manufactured conventionally by subtractive methods, and the smaller part with geometrical complexity, the tip of the mandrel, is built-up on it additively by laser melting. A further novelty of the developed die is the isolated feeding of the coolant up to the target area, close to die bearings, where the cooling shall be localized. Numerical and experimental investigations revealed that the profile’s exit temperature can be reduced locally and controlled which leads only to a moderate increase of the extrusion force. The experimental results show that the hybrid tools withstand the high mechanical and thermal loads which occur during hot aluminum extrusion.

Beschreibung: Machine tools have an impact on the environment due to their energy consumption. New strategies with focus on the reduction of the energy consumed by manufacturing processes have received significant attention owing to the rise of the electricity costs. This paper presents an experimental study related to the optimization of cutting parameters in turning of AISI 1018 steel. The aim of the study was to minimize the quantity of electrical energy required by the machine tool in order to perform the cutting operation. The material removal rate was set to a constant value in all the experimental trials so as to analyze the effect that the cutting parameters have on the energy consumed. Robust Design was used to determine the effects of the depth of cut, feed rate, and cutting speed on the energy required by the machine tool, considering two sources of noise in the experimental trials. The results of this work show that the techniques covered by the concept of Robust Design can be used to minimize the energy consumed and variation of the machining process.

Beschreibung: We propose a model for the statistical design of a variable sample size chi-squared control chart (VSS χ 2 control chart) for monitoring linear profiles. Performance measures of the proposed adaptive control chart are obtained through a Markov chain approach. Through a numerical example, which consists of a calibration application in a production process of semiconductors, the proposed chart is compared to the fixed parameter chi-squared control chart (FP χ 2 chart) to monitor the intercept and slope of the linear profile. From this example, it is possible to assess the potential benefits provided by the proposed chart. Also, considering simultaneous shifts in the intercept, the slope, and the standard deviation, a sensitivity analysis of the proposed chart for monitoring linear profiles is presented.

Beschreibung: The harmful effect on the health of superfine dust in industry is a serious problem. An especially important and complex task is the development of new methods for sedimentation of dust particles with a characteristic size of less than 10 μm. The solution offered by the authors involves a combined method of impact on industrial dust using high-frequency acoustic fields and spraying of a superfine water aerosol. Acoustic radiation sources are successfully applied to cleaning rooms from dust having fairly large particle sizes (10 μm and larger). The sedimentation of fine aerosols (particle diameter of 1–10 μm) is a more complicated challenge. The paper is devoted to substantiation of the acoustic sedimentation method for such aerosols. Good results were achieved when additional disperse phase was applied together with the ultrasonic source. Calculation results according to the mathematical model for coagulation and sedimentation, based on Smoluchowski’s equation, taking into account evaporation of liquid droplets, are given. Results of the experimental and theoretical study of the processes of acoustic sedimentation of superfine aerosols are presented. Recommendations are offered for the use of sources of ultrasonic radiation and sprayers of water aerosol for optimum removal of dust from workplace air.

Beschreibung: The present investigation analyses the force and torque developing during friction stir spot welding (FSSW) of thermoplastic sheets varying the main process parameters. In addition, measurements of the tool temperature and those of the material close to the welding region were carried out to better understand the variation of the forces during FSSW and quality of the joints. Experimental tests involving an instrumented drilling machine were performed on polycarbonate sheets. The study involved the variation of dwell time, tool plunge rate and rotational speed. Mechanical characterization and dimensional analysis of the joints were performed in order to assess the influence of the process parameters on the joint quality under considered processing conditions. According to the achieved results, using low values of the plunging speed has beneficial effects on both the process (reduction in the force and torque) and the mechanical behaviour of the joints. Increasing the tool rotational speed results in reduced processing forces and higher material mixing and temperature. The dwell time has a negligible effect on developing forces while it highly influences the material temperature, dimension of the welded region and consequently the mechanical behaviour of the joint.

Beschreibung: This research studies the cellular manufacturing system (CMS) controlled by kanban mechanism which defective items are produced in any production run of each product and rework is carried out to transform them into serviceable items. We consider and compare two different policies for rework where in the first policy rework is completed within the same production cycle and in the second policy rework done after N production cycles. Recently Aghajani et al. (2012) explain policy 2 and proposed a mixed-integer nonlinear programming (MINLP) model for this policy. In order to minimize total cost, MINLP model was developed for policy 1 to find simultaneously the optimal number of kanban, batch size, and number of batches. The cost function includes the cost of setup, holding, and transportation. Due to the high combinatorial structure of the problem, particle swarm optimization (PSO), and simulated annealing (SA) algorithms as meta-heuristic methods are proposed to solve the problem and numerical experiments are conducted to demonstrate the efficiency of the proposed algorithms. It is shown that both PSO and SA result are in a near optimal solution but the PSO algorithm gives a better performance than the SA method. Also, sensitivity analysis is carried out to study the effect of defective rate, holding cost, and setup cost variations on the total system cost is discussed the performance of these policies in different conditions.

Beschreibung: Tool condition monitoring has found its importance to meet the requirement of quality production in industries. Machined surface is directly affected by the extent of tool wear. Hence, by analyzing the machined surface, the information about the cutting tool condition can be obtained. This paper presents a novel technique for multi-classification of tool wear states using a kernel-based support vector machine (SVM) technique applied on the features extracted from the gray-level co-occurrence matrix (GLCM) of machined surface images. The tool conditions are classified into sharp, semi-dull, and dull tool states by using Gaussian and polynomial kernels. The proposed method is found to be cost-effective and reliable for online tool wear classification.

Beschreibung: This study proposes a high-precision compensation system using an on-machine noncontact measuring system to improve the manufacturing accuracy and efficiency of large-diameter aspheric mirrors by reducing profile errors arising from tool setting errors and machine positioning errors. By measuring a standard hemisphere, the assembly tilt angle of the measurement sensor can be calibrated. The grinding wheel setting offset can be calculated by comparing the measured profile and the ideal profile, and the profile error caused by wheel offset can be reduced by adjusting the grinding origin coordinate. According to the normal unit vector and residual error in the Z direction of the measuring points, the normal residual errors corresponding to the grinding points could be generated as well as the compensation grinding numerical control (NC) program. An 800-mm-diameter K9 mirror was ground to verify the proposed compensation grinding method. The profile error was reduced from 65 to 35 μm during the semi-finish grinding stage. By using the compensation grinding path, the profile accuracy was improved from 35 to 8 μm in the fine grinding stage. The proposed compensation method effectively improves the profile accuracy and manufacturing efficiency for grinding large-diameter aspheric mirrors.

Beschreibung: In this paper, we will perform a comparison between two approaches of dimensional synthesis of parallel robots. The first one concerns the single-objective optimization approach; in this case, the dimensional synthesis is expressed by taking into account only one performance criterion but enables to get a final solution if it exists. The second one concerns the multi-objective optimization approach; it enables to simultaneously take into account several performance criteria. However, this approach appears to provide a set of solutions instead of a single expected final solution which should directly enable to carry out the structural synthesis. In fact, the search of a single final solution is postponed to a further step where the designers have to impose and/or restrict certain parameters. And we will establish if it is really necessary to make a multi-objective optimization approach or if a single-objective is sufficient to reach the objectives set in the specifications (user requirements). A discussion is proposed concerning the arising questions related to each approach and leading to the optimal dimensional synthesis. The PAR2 robot with two degree-of-freedom is used to exemplify the analysis and the comparison of the two approaches. The proposed comparison can be applied to any classes of parallel robots.

Beschreibung: In order to generate efficient tool path with given precision requirements, scallop height should be kept under a given limit, while the tool path should be as short as possible to reduce machining time. Traditional methods generate CC curves one by one, which makes the final tool path far from being globally optimal. This paper presents an optimal tool path generation model for a ball-end tool which strives to globally optimize a tool path with various objectives and constraints. Two scalar functions are constructed over the part surface to represent the path intervals and the feedrate (with directions). Using the finite element method (FEM), the tool path length minimization model and the machining time minimization model are solved numerically. The proposed method is also suitable for tool path generation on mesh surfaces. Simulation results show that the generated tool path can be direction parallel or contour parallel with different boundary conditions. Compared to most of the conventional tool path generation methods, the proposed method is able to generate more effective tool paths due to the global optimization strategy.

Beschreibung: Ultrasonic-assisted grinding, a promising processing technique for machining hard and brittle materials, is already quite extensively employed in manufacturing industries. However, the material removal mechanism in ultrasonic-assisted grinding is not yet fully understood, which hinders its further application. This study investigates the material removal process in ultrasonic-assisted scratching (UAS) of SiC ceramics using both simulation and experiment method, in order to detail the material removal mechanism in ultrasonic-assisted grinding. A conventional scratching (CS) test was also carried out, but without ultrasonic vibration for comparison. The simulated workpiece is modeled by smooth particle hydrodynamic (SPH) particles. Results show the following: (1) the SPH method is suitable to investigate the material removal mechanism during ultrasonic-assisted grinding of hard and brittle materials. (2) The profile of scratching trace in ultrasonic vibration (UV) is a sinusoidal path. UV vibrating in the direction vertical to the workpiece results in material removed in either a continuous or a discontinuous mode. UV vibrating in the direction parallel to the workpiece expands the cutting area. (3) The groove depth in UAS is much bigger than that in CS. (4) UV results in the impact of the abrasive grain on the workpiece, causing the deformation field to spread from the impact site and leading to deeper scratching depths and larger radial and lateral cracks.

Beschreibung: With the emergence of new materials, personalized requirements for product performance, and new application background in polymer material industry, a new manufacturing mode is supposed to be studied. Based on cloud computing (CC) and big data techniques, a specific cloud manufacturing (CMfg) mode of polymer material industry has been proposed, which is different from that of continuous industries and that of discrete industries. The critical technologies of CMfg, including forecasting and demand management, storage and transportation management, advanced process control, manufacturing execution system, enterprise resource planning, etc., have been discussed. Besides the service composition optimal-selection (SCOS) algorithm for flexible manufacturing and the flexible polymer manufacturing system (FPMS), a typical product mode of CMfg is studied. Finally as a case, computer-aided process planning for blending material (CAPP-BM) was explored and a kind of fast searching algorithm for blending material crafts was proposed. The algorithm was applied to search target craft in more than 60,000 sections of the standard processes, production data, and environmental data, and finished its search within 10 min.

Beschreibung: In this paper, an inverse heat conduction method is applied to estimate the amount of the energy ( F c ) transferred to the workpiece during electric discharge machining (EDM) process. Embedded thermocouples which were connected to a four channel data logger were utilized to measure the temperature of a specific location on a rectangular workpiece during the EDM process. After temperature measurements were done, the 2-D heat conduction model of the workpiece and the Levenberg-Marquardt (LM) scheme were used to determine the energy transferred to the workpiece. This inverse procedure facilitates the determination of the heat energy at discharge-workpiece interface in EDM processes, which yet is a challenge for existing numerical models. The obtained results showed that the energy transferred to the workpiece varies with the discharge current and pulse duration from 5 % up to 45 %, which shows that the value of F c is a function of discharge current and pulse duration and that the fixed value of energy assumed in majority of the previous researches is not in accordance with real EDM conditions. Furthermore, the effects of machining parameters such as discharge current and pulse duration on F c were studied. It was evident that the F c has a direct but non-linear relationship with both discharge current and pulse duration, while discharge current has a higher impact on F c .

Beschreibung: Thermal errors are major contributor to dimensional errors of a part during precision machining. Error compensation is an effective method to reduce thermal errors. Accurate modeling of thermal errors is a prerequisite for thermal error compensation. In this paper, five key temperature points of a computer numerical control (CNC) machine tool were selected based on grey relational analysis method (GRAM). One thermal error model based on the five key temperature points was proposed using artificial fish swarm and ant colony algorithm-based back-propagation neural network (AFSACA-BPN). AFS is applied to generate initial pheromone value of ACA, which improves the computational efficiency of BPNs and prediction accuracy of thermal error modeling. One thermal error real-time compensation system was developed based on the proposed model. An experiment was carried out to verify the performance of the compensation system. Experiment results show that the diameter error of the workpiece reduced from 23 to 10 μm after compensation.

Beschreibung: Experimental and viscoplastic finite element analysis (FEA) of thermo-mechanical plastic deformation in nonisothermal warm deep drawing is studied using SS304. A nonisothermal deep drawing tool is used in a servo-motor-controlled press. Drawability window of SS304 under elevated temperatures (25–225 °C) and low to high strain rates (drawing speeds of 2.5, 25, and 50 mm/s) were determined. A viscoplastic thermal material model is adopted for nonwork softening material behaviors, as seen in low-temperature forming of SS304, and found to be easily applicable and quite satisfactory. Tensile and equi-biaxial bulge tests were conducted for more accurate flow stress data to be used in FEA. Measured punch load–stroke and cup’s curvilinear thickness (rolling/transverse) curves were successfully compared with predictions from the nonisothermal FE model of the warm deep drawing.

Beschreibung: In this article, the effect of cooling media on the residual stresses (RS) induced by a solid-state welding process is scrutinized through measuring and comparing RS caused by friction stir welding (FSW) underwater and in open air using the non-destructive ultrasonic method for aluminum AA7075-T6. Underwater FSW as a solid-state welding method can extend the application of solid-state welding techniques in marine industry. Results reveal that the longitudinal and transverse RS reduce under the water compared to open air. This reduction in the longitudinal RS is the maximum within the nugget zone (about 17 %). Meanwhile, such reduction for the transverse RS reaches 70 % within the heat-affected zone. In addition, under both air and water, the longitudinal RS is several times greater than the transverse RS and is in tensile and compressive states inside and outside the nugget zone, respectively.

Beschreibung: Machining-induced residual stress is important for the part performance. In the literature, various predictive models have been proposed for residual stress in one-pass machining without considering the multi-pass aspect. This study describes the regeneration of residual stress in multi-pass machining with thermo-mechanical loadings, in the full elasto-plastic state, captured using the Neumann-Duhamel principle. The residual stress is then analysed satisfying elastic-plastic relaxation in-between layers and at the boundaries. Large experimental data in milling of AA2121-T3 agreed well with model predictions, thus supporting the consideration of initial stress functions, materials cyclic plasticity and compatibility to allow for residual stress prediction in multi-pass machining.

Beschreibung: Different calibration strategies based on network measurements have been studied to improve the accuracy of a laser tracker having the beam source in the rotating head, thus allows us to determine if nominal distances are needed. Moreover, the minimum gauge needed to ensure a calibration valid result is characterised. First, the laser tracker calibration performance, using only network measurements without any nominal data known, has been studied. Different strategies have then been carried out, using reflector gauges as nominal data in the calibration procedure to determine the more suitable gauge in terms of accuracy and efficiency. The reflectors have been measured from different positions of the laser tracker. The gauge reflectors have been measured too with a coordinate measuring machine for obtaining the nominal data. The objective function to be minimised in the identification parameter procedure has been developed for every strategy for the distance criterion (distances between every pair of reflectors must be constant regardless of the laser tracker position from which they are measured). Then, two criteria, distance criterion and coordinate criterion (the reflector positions measured by the laser tracker are expressed in the same reference system and are then compared), have been used to evaluate the calibration performance. The analysis developed shows the improvement accuracy of every strategy studied.

Beschreibung: Crystallographic texture considerably affects the formability of crystalline materials. In this paper, the effects of BCC ideal rolling fibers—including α ,

Beschreibung: In the processing of large and ultra-large forgings, the heated billets need to be properly placed on the lower forging die as quickly as possible before the plastic forming, or else the cooling of billets incurs enormous risks to the operation. This paper presents a novel methodology for examining the positioning status of billets on a forging die based on multi-body dynamics simulation and design of experiment (DOE). Using this method, the position and posture of a billet can be theoretically predicted after falling into the cavity of lower die from a manipulator with varying initial states. The method can also clarify the initial geometrical position parameters of the billet that should be strictly controlled in the operation of the manipulator above the lower die. Furthermore, finite element method (FEM) simulation can be used to analyze plastic deformations of the billets on the lower die surface with varying states, to attain in-depth understanding of the influence of the geometric states of billets in forming processes. A case study of forging with Al 7050 indicates that the method can provide a valuable reference for the rapid positioning of billets on the lower die.

Beschreibung: The ANSYS software is used to establish the electromagnetic-structural coupling model and predict the electromagnetic sheet forming process. In comparison with experimental result, the maximum simulation error, about 4.5 %, occurs at the sheet center. Then, the simulation method is used to analyze the effect of discharge voltage on thickness distribution. The results indicated that the location of the maximum thickness reduction transfers from sheet center to the region near the sheet center (A region) and then to the region corresponding to the die corner (B region) with the voltage increases, which also cause the first principle strain changed. In addition, lager magnetic force and the material at sheet flange restrained to flow are the two reasons for the thickness reduction at B region. While the direction of material flows changed by inertial effect is the reason for thickness reduction at A region.

Beschreibung: In this paper, the formability of two-layer (aluminum-st12 steel) sheets in the deep drawing process was investigated through numerical simulations and experiments. The purpose of this research was to obtain more formability in deep drawing process. The limit drawing ratio (LDR) was obtained in deep drawing of two-layer metallic sheets, with aluminum inner layer which was in contact with the punch and steel outer layer which was in contact with the die. Finite element simulations were performed to study the effect of parameters such as the thickness of each layer, value of die arc radius, friction coefficient between blank and punch, friction coefficient between blank and die, and lay up on the LDR. Experiments were conducted to verify the finite element simulations. The results indicated that the LDR was dependent on the mentioned parameters, so the LDR and as a result the two-layer metallic sheet formability could be increased by improvement of these parameters in deep drawing process.

Beschreibung: This study aims to investigate two peel demolding schemes through numerical simulations and experimental studies in order to improve the yield rate of the automated system for demolding of the polydimethylsiloxane (PDMS) micropillars with aspect ratio of 6. Numerical models based on the explicit dynamic finite element analysis by using LS-DYNA are developed to identify an optimal demolding scheme which can minimize the maximum stress of microstructures during demolding. A scale-up modeling approach is proposed to increase the numerical time-step for microscale problems in order to reduce the computational time. The experimental tests are also carried out which agree with the findings from numerical simulations. From this study, the roller-based demolding system is identified as the optimal approach in our analysis cases which can minimize the distortion and collapse of micropillars. The yield rate of the roller-based demolding system in our experimental study can be up to 99 %.

Beschreibung: The size effect in cutting process that the specific cutting energy increases rapidly and nonlinearly as the undeformed chip thickness (UCT) decrease is discussed. To facilitate the discussion, the specific cutting energy is analyzed by separating the cutting mechanism into two parts: shearing and extrusion. The size effect of materials such as dislocation starvation was introduced to explain the increase of specific cutting energy. In conventional cutting, shearing dominates the size effect. And as the UCT reduces, the effect of tool radius is not ignorable, and extrusion participates more in describing the size effect. When the UCT is on the nanometric scale, extrusion dominates the cutting process. Besides that, the cutting energy was further separated into surface generation energy, material disorder energy, and heat generation energy. Each of them was discussed individually. The results show that the size effect of materials plays a major role in the change of specific cutting energy. And the other aspects like surface generation and material disorder also determine the size effect in cutting process.

Beschreibung: Based on the crack mechanism of hot forming, the causes of cracks occurring during the hot forming of complex structural parts were investigated in this study. High temperature flow stress model of ultrahigh strength steel (UHSS) BR1500HS was established using the true stress–strain curves of BR1500HS in high-temperature tensile. A finite element model (FEM) was built to investigate the causes of defects in hot forming, particularly the necking occurring at the end parts in plan stress status. Then, hot forming process and structure optimizing methods were proposed. According to the results of numerical simulation, it can be concluded that the indirect hot forming process can avoid forming defects and optimize preforming drawing height to 24.5 mm. Through changing the end size of blank to control the metal flow, crack occurring at the end of parts can be solved, since the material in two-way tensile stress state can flow compensation in one direction and therefore reduce the flow resistance. The experimental results are in good agreement with numerical simulation results, which indicates that the proposed method can avoid defects and meet the design requirements.

Beschreibung: The deforming zone in the die determined by the cross-sectional shape of the final product plays a key role in the extrusion process affecting the extrusion pressure and product quality. Therefore, prediction of the optimal profile of the deforming region is the main objective for an effective extrusion process. In this study, using the analogy between the conventional plasticity theorem and electrostatics, the notion of equi-potential lines (EPLs) was applied to accurate representation and 3D design of the deforming region in the extrusion process of a complex section. To implement the analogy in the extrusion, the initial and final shapes were considered, and two different potentials were assigned between the inlet and outlet surfaces. Then, the EPLs were drawn that show the minimum work path between the entry and exit sections. The drawn EPLs were connected to build up a 3D-profile for the deforming region in the extrusion process. In addition, the EPLs were used in accurate representation of the deforming region using high-order polynomial curves. The effectiveness of the proposed method was examined using a complex section (U-shaped) from the literature. Then, the extrusion pressure for different profiles in the deforming region was analyzed numerically and experimentally. Moreover, the obtained polynomial curves were used in the upper bound (UB) solution for prediction of the extrusion pressure. There were reasonable agreements between the analytical, numerical, and experimental results. An acceptable reduction in the extrusion pressure for 3D modelling of the deforming region with the EPLs was reported. It was shown that the EPLs could be used for accurate representation of the deforming region in the extrusion of complex sections.

Beschreibung: In this study, induction brazing was performed on diamond grits coated with amorphous NiCrBSi alloy (1.6-μm thick) deposited by physical vapor deposition (PVD). The brazing alloy exhibited better wetting toward the coated diamond grits than toward the uncoated diamond grits during induction brazing. The fine chromium-carbon compounds were evenly distributed between the brazed diamond grits with coating and the brazing alloy. However, the bulky chromium-carbon compounds were unevenly distributed between the brazed uncoated diamond grits and the brazing alloy. Cylindrical grinding of casting aluminum ZL102 plate with thickness of 15 mm was also performed using the brazed diamond burs fabricated with the coated diamond grits and uncoated diamond grits, respectively. The falloff percentage of brazed coated diamond grits was lower than that of brazed uncoated diamond grits. Accordingly, the temperature of processing arc area of the brazed diamond bur fabricated with the coated diamond grits was lower than that of the brazed diamond bur fabricated with the uncoated diamond grits, and its rate of removal of material was higher than that of the brazed diamond bur fabricated with the uncoated diamond grits.

Beschreibung: The pre-cracked Brazilian disc specimens of rock-like materials (Portland Pozzolana cement (PPC), fine sands, and water) are especially prepared in a rock mechanics laboratory to study the breaking process of brittle solids. The Brazilian discs may contain one, two, three, four, and five (parallel) center slant cracks (45° to the horizontal) under compressive line loading. The breaking load of the pre-cracked disc specimens is measured showing that as the number of cracks increases, the final breakage load of the specimen decreases. The experiments are carried out under compression (just like the Brazilian tests used for measuring the indirect tensile strength of intact rocks). It has been experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of compressive line loading in the pre-cracked Brazilian discs. The same specimens are numerically simulated by a higher order displacement discontinuity method (HDDM). The effect of bridge area and orientation of cracks on the cracks coalescence and breakage path of the pre-cracked Brazilian discs specimens are simultaneously studied.

Beschreibung: Geophysical and geochemical studies were carried out in the eastern part of Lagos metropolis to determine the possible contamination of subsurface soils and groundwater as a result of dumping of waste into the canal. The geophysical method involved the use of 2D electrical resistivity imaging which was acquired along five (5) traverses, while the geochemical method involved the physicochemical analysis of water samples from nine (9) wells within the study area. The geochemical study includes the analysis of physical parameters like total dissolved solids (TDS), electrical conductivity (EC), pH and temperature. Seventy elements which include trace elements (such as As, B, Ba, Cd, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Se, U and Zn), major cations (such as Ca, K, Mg and Na) and anions (Cl and Br) were analysed, and the concentrations of the elements were compared with the World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ) permissible level for drinking water. Geophysical results show that the lithology is composed of topsoil, clayey sand, peat and sand. 2D electrical resistivity tomography revealed that the leachate and polluted water from the canal have percolated to the subsurface soil down to a depth of about 37 m with low resistivity values of 1–13 Ω m. In addition to this, result of physicochemical analysis of water samples shows that Mn, Br, TDS, and EC were high in some wells, above the WHO and NSDWQ standard. It was deduced that the subsurface has been invaded by the polluted water from the canal consequently, making the groundwater unsuitable for human consumption.

Beschreibung: When machining titanium alloys at cutting speeds higher than 60 m/min using cemented carbide cutting tools, the tool wears out rapidly. With the ever-increasing use of titanium alloys, it is essential to address this issue of rapid tool wear in order to reduce manufacturing costs. Therefore, the intention of this study was to investigate all possible tool wear mechanisms involved when using uncoated carbide cutting tools to machine Ti6Al4V titanium alloy at a cutting speed of 150 m/min under dry cutting conditions. Adhesion, diffusion, attrition, and abrasion were found to be the mechanisms associated with the cratering of the rake surface of the cutting tool. The plastic deformation of the cutting edge was also noticed which resulted in weakening of the rake surface and clear evidence has been presented. Based on this evidence, the process of the formation of the crater wear has been described in detail.

Beschreibung: Temperature and material flow behavior during friction spot welding of Alclad 7B04-T74 aluminum alloy were studied by both numerical simulation and welding experiment. The Alclad 7B04-T74 aluminum alloy sequentially experienced solid solution treatment at 465 °C, low temperature artificial aging at 120 °C, and high temperature artificial aging at 180 °C. During welding, the material which flowed into the sleeve cavity suffered from higher temperature, and the peak temperature in the stir zone was higher than the incipient melting temperature of the base material. Accordingly, the eutectic films along the grain boundaries can be observed in the stir zone after welding. The peak temperatures in the thermo-mechanically affected zone and the heat affected zone were lower than the solution temperature and higher than the artificial aging temperature of the base material. In the sleeve retreating stage of the welding process, the material in the sleeve cavity flowed downward out of the sleeve cavity, and then it flowed laterally and upward to fill the gap left by the retreating sleeve. Such a material flow path resulted in the “U-shaped” morphology of the bonding ligament, the upward curving of the hook, and the upward distortion of the grains in the thermo-mechanically affected zone.

Beschreibung: Probability distribution and extreme value analysis were carried out on total suspended particulate matter (TSP) in Kuwait. The measured TSP data, available for about 10 years from three different locations in Kuwait, viz., Managhesh, Shuwaikh, and Kuwait City were used. For probability distribution analysis, four theoretical distributions were considered, namely Rayleigh, exponential, Gumbel, and log-normal distribution. Based on the study, it was found that log-normal distribution represented the measured daily average TSP value in Kuwait. The expected extreme daily average TSP values for 10-, 25-, 50-, and 100-year return periods were estimated based on Gumbel, exponential, and Weibull extreme value distributions for these three locations. For 100-year return period, the expected TSP values in Managhesh were 5270, 5920, and 4584 μg/m 3 , based on Gumbel, exponential, and Weibull extreme value distributions, respectively. For the same return period, the expected TSP values in Shuwaikh were 11,255, 12,592, and 8771 μg/m 3 , and in Kuwait City, 7109, 8136, and 6494 μg/m 3 , based on Gumbel, exponential, and Weibull extreme value distributions, respectively. During an extreme dust storm in Kuwait, an extreme TSP of 9619 μg/m 3 was recorded on 25 March 2011. The results of this study are an important input to understand the probability distribution of TSP and also for the analysis on the impact of TSP on the socioeconomic development and on the respiratory health issues in Kuwait.

Beschreibung: In order to reduce the adverse effects on environment and avoid health problems caused by the excessively used cutting fluids, a green machining technology, minimum quantity lubrication (MQL), is drawing more and more attention. The cryogenic minimum quantity lubrication (CMQL) technique which combines the advantages of cryogenic air and MQL can improve cooling and lubricating performances during machining H13 steel. Internal cooling cutters have been widely employed to feed the cutting medium to the cutting zone directly. In this research work, cutting forces and tool wear were analyzed during side milling H13 steel with three kinds of internal cooling milling cutters under CMQL condition. The experimental results showed that the milling cutter with double straight channel (DSC) performed best in extending tool life and reducing cutting forces. In the perspective of economy and environmental protection, internal cooling cutter with DSC is recommended in cutting of H13 steel under CMQL condition.

Beschreibung: Considering the traditional power amplifier has the disadvantage of poor reliability and flexibility, a three-level pulse-width modulation (PWM) power amplifier which is based on a novel field-programmable logic gate array (FPGA) algorithm and hardware solution is proposed. The power amplifier can provide various signals flexibly and realize rapid response of the magnetic suspension spindle in micro-electrical discharge machining (EDM). In this paper, the principle of three-level PWM amplifier with half bridge and full bridge power circuit is introduced. According to different functions, the amplifier is divided into four function modules which include PWM signal generator module, voltage signal convert module, bootstrap drive module, and power bridge module. PWM signal generator module is also divided into four sub-modules in term of a new FPGA algorithm. Voltage signals are converted by high-speed photo coupler HCPL-2630. IR2110S chips are applied to drive the half bridge and full bridge power circuits. According to Kirchhoff voltage law, when the period of PWM signals is 50 μs and the duty cycles are larger than 0.76 and 0.665, the average current of half bridge and full bridge are more than 3 and 4 A; however, the ripple of the half bridge and full bridge are still less than 0.25 and 0.2 A, this advantage is suitable for the control system of magnetic suspension spindle. Test results of the average current and ripple are close to theoretical value. The axial response frequency of the spindle can reach 125 Hz, using this power amplifier and the magnetic suspension spindle, micro EDM can be achieved in Z axis with 1.2 mm stroke.

Beschreibung: This paper presents an improved methodology for evaluating the position and orientation errors of airfoil sections of a manufactured aero-engine blade. The existing method estimates these errors by finding rigid-body transformations with translational and rotational parameters altogether to best match the inspection data points onto the design airfoil profiles. Such transformations lead to unreliable evaluation results due to combining the position and orientation errors with each other. This paper proposes to decouple the position and orientation errors in their evaluation in order to avoid the combining effect. To isolate the position error from the orientation error, an important location tolerance evaluation feature, the centroid of a manufactured airfoil section, must be correctly identified from the sectional inspection data points. Identifying the centroid location directly from discrete data points is subject to an error caused by biased area calculations on the pressure and suction sides of an airfoil. This work proposes to reconstruct a valid airfoil profile from the inspection data points for each airfoil section to overcome the area bias problem and to maintain consistency in identifying the centroid. With the centroid of each inspected airfoil section identified, the position error and the orientation error can then be evaluated in sequence. A series of case studies has been performed to demonstrate the effectiveness of the proposed methodology and how it is able to prevent wrongful rejection/acceptance of geometrically acceptable/unacceptable blades as well as incorrect modification of the related manufacturing processes.

Beschreibung: A three-dimensional (3D) micromechanical finite element (FE) model of machining of fiber-reinforced polymer (FRP) composites was developed in the paper. The FE modeling considers the three phases of a composite, in which the interphase between the fiber and matrix can realize interfacial debonding to represent the failure of composites and allow heat transfer. The machined surface observations and surface roughness measurements of carbon fiber-reinforced polymer (CFRP) composites at different fiber orientations were done firstly, and then, the model predictions of the machining responses, such as cutting force, temperature, and surface roughness, at different fiber orientations were compared with various experimental data for model validation. It is indicated that the three-phase micromechanical model is capable of precisely predicting machining responses and describing the failure modes of fiber shearing or bending related with fiber orientations in the chip formation process. To investigate the complex coupling influences of multiple machining parameters on the key responses of CFRP composites, the single-factor analyses of each machining parameter were first carried out, and then, the multi-factorial analysis of multiple machining parameters was performed based on the orthogonal design of experiment and the analysis of variance (ANOVA) to quantitatively compare the influences of these key machining parameters on the cutting force and surface roughness. It was found that the fiber orientation angle, depth of cut, and cutting speed prove to be the important factors affecting the cutting force and surface roughness and that the coupling effects of these machining parameters all are relatively negligible in the machining of CFRP composites.

Beschreibung: Assembly system complexity, especially welding system complexity introduced by auto-body product personalization is regarded as a major contributor of uncertainty in the system planning and designing. The welding system complexity is defined based on information entropy theory, the station-level integrated complexity model, and system-level complexity flow model are established to obtain the complexity source of welding system. Complexity source sensitivity indices are proposed to indentify key station and key equipment that contribute most to the complexity. Based on the application of auto-body side welding line case, the result indicates that the proposed complexity model and key complexity source identifying and diagnosing process can be used as the decision support tool of auto-body welding system.

Beschreibung: Single point incremental forming (SPIF) is a relatively new manufacturing process that has been recently used to form medical grade titanium sheets for implant devices. However, one limitation of the SPIF process may be characterized by dimensional inaccuracies of the final part as compared with the original designed part model. Elimination of these inaccuracies is critical to forming medical implants to meet required tolerances. Prior work on accuracy characterization has shown that feature behavior is important in predicting accuracy. In this study, a set of basic geometric shapes consisting of ruled and freeform features were formed using SPIF to characterize the dimensional inaccuracies of grade 1 titanium sheet parts. Response surface functions using multivariate adaptive regression splines (MARS) are then generated to model the deviations at individual vertices of the STL model of the part as a function of geometric shape parameters such as curvature, depth, distance to feature borders, wall angle, etc. The generated response functions are further used to predict dimensional deviations in a specific clinical implant case where the curvatures in the part lie between that of ruled features and freeform features. It is shown that a mixed-MARS response surface model using a weighted average of the ruled and freeform surface models can be used for such a case to improve the mean prediction accuracy within ±0.5 mm. The predicted deviations show a reasonable match with the actual formed shape for the implant case and are used to generate optimized tool paths for minimized shape and dimensional inaccuracy. Further, an implant part is then made using the accuracy characterization functions for improved accuracy. The results show an improvement in shape and dimensional accuracy of incrementally formed titanium medical implants.

Beschreibung: In electrical discharge machining (EDM) process, one of the most important aspects is the surface quality of the workpiece. When a uniform and thick recast layer is achieved with characteristics of low roughness, high hardness, and the absence of pores and micro-cracks, it acts as a kind of coating. Such surface is required by mold-making industry, where the molds are subjected to chemical and abrasive wear, and the surface needs to present high resistance against corrosion and abrasive forces. The use of powder particles suspended in the dielectric is a way to provide such improvement and, at the same time, avoiding the need for subsequent polishing. This work investigated the influence of silicon and manganese powders with fine particle sizes, using two different concentrations, suspended in the dielectric when EDM machining AISI H13 tool steel. It evaluated the surface roughness, hardness, and the chemical composition and micro-structure of the recast layer; using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) techniques. The best results were obtained for silicon powder; presenting the surface roughness improved about five times, when compared to the conventional EDM process, as well as a thick and uniform recast layer without micro-cracks and pores. The silicon and the manganese powders also promoted an increase of the recast layer hardness of about 40 % when compared to the conventional EDM process.

Beschreibung: It has been proven that error compensation is a key technique to improve machining accuracy. However, existing iteration and recursive compensation algorithm is difficult to realize. Hence, a simple and rapid compensation method is considerably necessary for engineering application. In this paper, a novel compensation strategy just by algebraic operation was first proposed for machining accuracy improvement. Error motion transformation was introduced to build the position-independent geometric error (PIGE) model according to homogeneous transformation matrix (HTM). Then, the analytical numerical control (NC) code expression with error compensation was derived and used for NC code generation. In addition, the presented method is appropriate for post-processing of non-orthogonal machine tool. At last, simulation and cutting experiment were demonstrated to verify the feasibility and effectiveness of the proposed method. Taking hemisphere surface as the test object, the simulation results showed that the effects of PIGEs could be eliminated by the proposed method. The experiment results with compensation indicated that the machining accuracy improved to about 14 % compared with those without compensation.

Beschreibung: The study aims to obtain the effect of forming parameters on multi-stage cold forging with 20MnTiB steel by performing a series of physical simulation and then verified by producing experiment of high-strength bolt. Physical simulation was performed through Gleeble 3500 compression tests; the mainly forming parameters such as strain rate (10 0 ∼10 1 ), deformation degree (20∼80 %), and number of stages were discussed. The results showed that the strain rate has little effect on the microstructure and the mechanical property. However, the number of stages and the deformation degree have an appreciable effect on the sample microstructure, of which the pearlite grain is fined and ferrite grain is elongated as fiber. The adiabatic thermal temperature rises from 20 to 142 °C with a 60 % deformation degree at a strain rate of 10 s −1 . Finally, the deformation properties of bolts can compare with the physical simulation results.

Beschreibung: In this paper, a visual, data-driven operational level lean maturity model is developed. The model can be used to assess level of lean maturity and to compare it to performance results in different axes of manufacturing cells in order to evaluate lean effectiveness. As demonstrated in this paper, to measure effectiveness of lean manufacturing, both inputs (tools and processes) and outputs (performance) are measured separately and analyzed together. A case study is carried out for gathering data, analysis, and explanatory study of results. Qualitative and quantitative data on lean capability and performance of two manufacturing cells is collected using historical data and audit. A scoring system based on the major and minor non-conformances is suggested to quantify the indicators of leanness. Minimum of fuzzy membership values is selected to calculate overall performance. Then, the results of leanness are compared with performance to highlight the gaps of lean effectiveness. Results of the study show that the developed model can be used to measure both leanness and lean effectiveness through assessment of lean performance. The model can be applied by practitioners as a framework to design and develop a company-specific lean maturity model.

Beschreibung: Kadabora-Suwayqat area, in the Central Eastern Desert of Egypt, is built up by a wide variety of non-consanguineous, basement rock units, which represent a tectono-stratigraphic suite within the frame of the Late Neoproterozoic, Pan-African Arabian-Nubian Shield. They were developed from different magma sources at varied tectonic settings through subsequent tectono-magmatic processes. They cover a wide compositional range of the Pan-African legend in the Eastern Desert of Egypt comprising ophiolitic, island-arc, and within-plate assemblages. The ophiolitic serpentinites were obducted onto arc-related metavolcanics and intruded by gabbroic and syn-late to post tectonic granitoids. Geochemically, the precursor of the ophiolitic serpentinites seems to be peridotite (harzburgite). The basic, intermediate, and acidic metavolcanics imply a transitional stage between an island-arc and a proper active continental margin setting. They exhibit with the gabbroic rocks a diagnostic subduction-related island-arc, calc-alkaline affinity. The granitoids comprise both arc-related, calc-alkaline I-type and within-plate, anorogenic A-type varieties. These rocks have been successfully discriminated on Landsat 8 images including Minimum Noise Fraction (MNF; 4, 3, 7), Principal Component Analysis (PCA; PC6, PC2, PC7), and various band ratios (b6/b2, b6/b7, b6/b5×b4b5) and (b7/b6, b7/b5, b5/b3). ASTER clay index (5×7/6) and silica index (10/13) discriminated the granitoid rocks, while the serpentinite-talc carbonate and metavolcanic rocks are distinguished on the ASTER images of amphibole index (6+9/7+8) and (6/8).

Beschreibung: The wall thickness of hollow turbine blade has emerged as a significant cause of blade retirement. The precision of the final wall thickness of blade is mainly inherited from its corresponding wax pattern. The layout scheme of ceramic locators has a great influence on the wall thickness of wax pattern. A good layout of ceramic locators can significantly reduce the wall thickness shifting. To address this issue, a stable locator layout is needed to reduce the error transferring. The main purpose of this study is to find an optimal localization scheme for ceramic core. Firstly, the mathematical model of ceramic core localization was built based on the fixture design theory. Then, the optimal algorithm of locator layout design was studied. The D-optimality criterion has been chosen as optimal design criterion. Finally, two demonstration cases were presented. A localization scheme for real ceramic core was achieved and verified by using Monte-Carlo method. Moreover, the localization scheme was validated through experiments. Both simulation and experimental results indicated that the optimal localization can significantly reduce the input error.

Beschreibung: Inaccuracies in conventional tolerance characterization methods, which are based on worst-case and root-square-error methods, as well as inefficiencies in Monte Carlo computational methods of statistical tolerance analysis, require an accurate and efficient method of statistical analysis of geometric tolerances. Here, we describe a unified error distribution model for various types of geometric tolerance to obtain the distribution of the deviations in different directions. The displacement distributions of planes, straight lines, and points are analyzed based on distributions within tolerance zones. The distribution of the displacements of clearance fits is then determined according to the precedence of the assembly constraints. We consider the accumulated assembly variations and displacement distributions, and an analytical model is constructed to calculate the distribution of the deviations of the control points and the process capability index to validate the functional requirements. The efficiency of the method is shown by applying it to the assembly of a single-rod piston cylinder. The results are compared with other statistical methods of tolerance analysis. We find an improvement of approximately 20 % in tolerance analysis, and the process capability index of the assembly procedure was reduced by 10 %.

Beschreibung: This paper aims to reveal the material removal mechanisms of the elliptical vibration cutting (EVC) and present the predicted model of orthogonal cutting force. Further study of mechanism will be helpful to explain the phenomena that EVC can reduce the cutting force, lower cutting temperature, and improve the surface integrity. In each overlapping EVC cycle, almost all the parameters are time-varying, of which two important factors are focused: (i) transient thickness of cut and (ii) transient shear angle. The analysis model simplified the complex process of the EVC as conventional cutting (CC) which considering two transient variables. This paper presents a non-equidistant shear zone model to predict the shear angle, tool–chip friction angle, and shear stress in CC under the same conditions of the EVC. Then, the transient thickness of cut and transient shear angle are investigated. Thus, an analytical model of the force in EVC is proposed. The model is available to predict the cutting force of the EVC accurately without any experimental parameters in CC. In addition, experimental results available in the literature are conducted for comparison, which are in well agreement with the analysis model.

Beschreibung: With pervasive applications of new information technology, a larger number of manufacturing big data is generated. This paper considers the unrelated parallel scheduling problem within the background of “big data and cloud technology for manufacturing.” Traditional unrelated parallel problem has been extensively investigated, and the main objective has been to improve production efficiency. With regard to the environmental concern, there has been limited literature. Therefore, this paper considers an unrelated parallel machine scheduling problem with the objective of minimization to the total tardiness and energy consumption where the energy consumption on each machine is also unrelated parallel. First, we give a mathematical model of this problem. Second, ten heuristic algorithms are, respectively, proposed based on the priority rules, the energy consumption, and the combinational rules due to the complexity of this problem. Finally, in order to test the performance of these ten algorithms, computational experiments are designed. In the computational experiments, lots of instances are generated, and the computational results indicate that the algorithms based on the combinational rules outperform the ones based on the priority rules and energy consumption, with respect to the unrelated parallel scheduling problem proposed in this paper.

Beschreibung: Increasing use of the nitinol (NiTi), the nickel titanium alloy is primarily due to the fact that the medical fraternity is looking more toward less invasive medical procedures. Microengineering features such as microslots, grooves, and profiles of size 0.5 mm and below are required in the NiTi alloy-based medical components, but the material offers tremendous manufacturing difficulty due to its superior mechanical properties. High-speed micro machining was viewed as a possible way to process the NiTi-based medical components without compromising the productivity and quality of the machined surface textures. A study was undertaken to characterize the high-speed micromachining process for the NiTi alloy. More specifically, the optimization of the machining process parameters with the objective of reducing the milling forces and burr formation was focused upon. The study unveiled that the understanding the tool-work interface behavior is critically important for maximizing the machining performance of the NiTi alloy. Machining behavior characterized in terms of low cutting forces and reduced burr size was achieved at 15 m/min of cutting speed when the NiTi alloy undergoes a transition from B2 phase to B19 phase.

Beschreibung: Rapid prototyping fabricates physical prototypes from three-dimensional designing models using the additive process with layers. Aims at reducing the inevitable volumetric error induced in phrase of model slicing which impacts the shape accuracy of fabricated entity, a fast determining scheme of optimal slicing orientation for least volumetric error is proposed. The work analyses the staircase effect between two consecutive layers, then infers a direct computing formula of volume deviation of a whole model. Introduces the term of area weighted normal to express the significant effect of facet area on volumetric error and converts the optimal orientation determining problem to the least absolute deviation linear regression issue. Employs prominent components analysis on weighted normal set to obtain an approximate orientation efficiently, then optimizes the solution through few searchings in neighboring orientation space. The validity and efficiency of the algorithm are evaluated on several examples. Results demonstrate that proposed algorithm consumes less than 32 % of computation load and adaptively obtains the optimal slicing orientation.

Beschreibung: Defects diagnosis and condition surveillance of production and manufacturing rotating machinery in a plant is very important for guaranteeing production efficiency and plant safety. Condition surveillance for gear and bearing defects diagnosis for all rotating machines is a serious job because they cause accidents and consequently great production losses. For gear and bearing faults, and early detection especially in the gearboxes, researchers in the conditional maintenance and vibratory analysis used different methods and techniques in signal processing, among those and in full rise, demodulation by wavelets multiresolution analysis (WMRA) and high-frequency resonance technique (HFRT), based on the Hilbert transform, which allows filtering and the demodulation at the same time. In this paper, we propose to make a precise diagnosis for gears and bearings combined faults detection and identification in a laboratory test rig which simulate a rotating machine like in the manufacturing processes using WMRA and HFRT techniques. First of all, we applied WMRA method on simulated signals of gear or bearing defects or the combination of them, then we applied it on real signals measured on a test rig of the LMS laboratory in the University of Guelma.

Beschreibung: In this paper, we propose a new fuzzy group multi-criteria decision making method and apply it to determine the critical path in a project network. The criteria used here are time (expected duration), cost, risk, and quality of the project activities that are considered critical in project management. As each criterion has its independent level of importance in the critical path selection, the weights of the project criteria are also considered in the analysis. Considering that the information in terms of various project activities and criteria weights are often incomplete and/or uncertain in real-world situations, the essential information in terms of the criteria and project activities are obtained using triangular fuzzy numbers and/or linguistic variables that are mapped to triangular fuzzy numbers, wherever appropriate. The proposed method involves fuzzy evaluation based on the fuzzy information of the possible project paths on each criterion leading to the strength and weakness index scores of the project paths. We define a measure of criticality termed as the total performance score of each project path obtained using its strength and weakness index scores. The path that has the highest measure of criticality is selected as the critical path. A numerical illustration is provided to demonstrate working of the proposed methodology. Further, a case study from manufacturing engineering industry is also presented to better justify the applicability and potentials of the proposed methodology. A comparison with closely related fuzzy multi-criteria decision methods for the critical path selection is done to analyze the performance of the proposed methodology.

Beschreibung: A chemical mechanical grinding (CMG) wheel was developed for planarization of silicon wafers, which consists of magnesium oxide (MgO) abrasives and calcium carbonate (CaCO 3 ) additives, mixed with 25 % weight percentage of magnesium chloride (MgCl 2 ) solution. It was shown that chemical reactions occurred during the grinding process, which formed a softened layer on the top of silicon substrate. The reactants could be much more easily removed by mechanical abrasion than the removal of Si phase itself. The newly developed wheel was able to produce a similar surface integrity to that obtained from chemical mechanical polishing (CMP), i.e., the CMG achieved a surface roughness of 0.5 nm in R a and a subsurface damage layer of 13 nm thick. The CMG process developed thus has great potential for back grinding or thinning of silicon wafers in order to replace CMP.

Beschreibung: The topography of fixed abrasive grinding pad has a significant effect on the process of grinding analysis. A new numerical modeling technique has been proposed to generate the grinding pad topography with spherical grains in this paper. The simulation result was given by software. Five fixed abrasive grinding pads with different grain sizes were measured by using a confocal scanning laser microscope. Comparing the results of simulation and the experiment, it can be concluded that the simulated profile of the grinding pad is corresponding well with that of the actual pad.

Beschreibung: Underwater friction stir welding is an alternative method to improve the mechanical properties of the weldments by controlling the temperature level. Owing to the limitation of temperature measurement in practice, the finite element modeling is the best tool to investigate the process. It is still not clearly known as to what extent the temperature field of joint is influenced by operational parameters in underwater friction stir welding. In this paper, finite element modeling of friction stir welding in the air and underwater were performed for Al6061-T6 alloys to control the thermal cycles. In addition to cooling effect, the influence of welding speed and rotational speed on the maximum temperature in workpiece was investigated. For this purpose, three-dimensional modeling has been done with ANSYS. The model results were then examined by experimental data, and a reasonable agreement was observed. It is found that due to water cooling effect, heat is dissipated in faster rate which leads to low peak temperature in underwater welding compared to normal welding in air, while such relationship was not seen in high welding speeds. The reason is that at high welding speeds, workpiece temperature decreases, and region of boiling water in underwater welding is reduced. This causes that heat will be dissipated from workpiece surface in faster rate. Tool rotational speed has significant effect on thermal cycles than welding speed. Moreover, in normal friction stir welding, the peak temperature diminishes with respect to welding speed in faster manner in comparison with welding in underwater.

Beschreibung: Laser drilling has swiftly become an economical and well-regulated substitute to conventional hole drilling methods such as wire EDM, punching, broaching, or other prevalent destructive processes, because of cleanliness, accurate results, precise holes, fast material removal rate, and possibility to make holes. Prompt expansion of laser technology in current years gave us facility to regulate laser input factors such as lamp current, pulse frequency, air pressure, and pulse width. The dimensional accuracy and quality of holes are very important for some specific applications of holes. Circularity of drilled hole at entry and exit, and taper are very important attributes which influence the quality of a drilled hole in laser drilling. For this reason, the experimentation based on central composite design is carried out on austenitic stainless steel for examining the effect of laser parameters, i.e., lamp current, pulse frequency, gas pressure, and pulse width, on the quality of drilled holes. A total of 31 experiments were carried out. Later, the models were predicted for output responses using response surface methodology and then tested for adequacy. It is found that the response surface methodology (RSM) predicted models are in close agreement with the experimental values. Hence, the models may be further used for optimization of process parameters using evolutionary algorithms.

Beschreibung: In this paper, a contribution to the determination of reliable cutting parameters is presented, which is minimizing the expected machining cost and maximizing the expected production rate, with taking into account the uncertainties of uncontrollable factors. The concept of failure probability of stochastic production limitations is integrated into constrained and unconstrained formulations of multi-objective optimization problems. New probabilistic version of the nondominated sorting genetic algorithm P-NSGA-II, which incorporates the Monte Carlo simulations for accurate assessment of cumulative distribution functions, was developed and applied in two numerical examples based on similar and anterior work. In the first case, it is a question of the search space that is completely ‘closed’ by high natural variability related to the multi-pass roughing operation: in this case, the failure risk of technological limitations are considered as objectives to minimize with economic objectives. The second case is related to deformed search space due to the uncertainties specific to finishing operation; therefore, the economic objectives are minimized under imposed maximum probabilities of failure. In both situations, the efficiency and robustness of optimal solutions generated by the P-NSGA-II algorithm are analysed, discussed and compared with sequence of unconstrained minimization technique (SUMT) method.

Beschreibung: Process capability indices have been widely used in industries to assess the performance of the manufacturing processes. Various different multivariate capability indices have been introduced. In this paper, a new multivariate capability vector is proposed under the assumption of multivariate normality, to assess the production capability of the processes that involve multiple product quality characteristics. Also, we investigate the relation between this index and process centering, as well as the relation between this index and the lower and upper bounds of percentage of non-conforming items manufactured. Two real manufacturing data set are used to demonstrate the effectiveness of the proposed index.

Beschreibung: In this study, classical and vortex tube cooling methods are compared in the pocket machining of AA5083-H36 alloy with uncoated cemented carbide cutting tool. The effects of cutting speed, feed rate, axial/radial depth of cut and nose radius and their two-way interactions on the surface roughness, and the optimization of surface roughness are investigated via Taguchi method. The experiments conducted based on Taguchi’s L16 orthogonal array (OA) are assessed with analysis of variance (ANOVA) and signal to noise (S/N) ratio. As a result, in both cooling methods, it is obtained that roughness correlates negatively with cutting speed and radial depth of cut and positively with feed rate and axial depth of cut. While in the cooling with vortex tube, lower average R a values are observed in the experiments with the nose radius of 0.8 mm, in the classical cooling almost no change is obtained. Lastly, optimum roughnesses for the classical and vortex tube cooling are obtained as 0.164 and 0.188 μm, respectively.

Beschreibung: The demands placed on automation of cell production processes for IT products are becoming increasingly sophisticated. Dual-arm robots are drawing particular attention as a process solution because they offer flexibility and can work in a similar manner to a human operator. In this paper, we propose an automation system for cellular phone packing processes that uses two dual-arm robots. The applied robots are designed with specifications that meet the requirements of the cellular phone packing tasks. In addition, a robotic cell production system is proposed that applies a task allocation method to perform an efficient packing job for cellular phones. In particular, each task is assigned with the intention of reducing the takt time , which is the time taken to finish a single product in the production line and to avoid collisions between the two robots. Finally, we implement some of our results in a demonstration of a packing job that involves filling five unit boxes with seven kinds of accessories.

Beschreibung: Laser forming experiments were conducted on AISI 304 stainless steel flat sheet to study the effects of process parameters and for developing an empirical model of bending angle, which could be useful to produce a class of developable surfaces from it using multiple parallel laser scans. Central composite design of experiments was used to perform the experiments, input–output relationships were established, and optimization of laser forming process under temperature gradient mechanism was carried out using a response surface methodology based on the experimental data. Laser power, scan speed, spot diameter, scan position, and number of scans were taken as input variables, and bending angle was considered as the output. The performance of the developed model was validated through a set of experimental data. The optimum process parameters for obtaining the maximum bending angle were determined, and those were verified through the real experiments. The effect of work-piece geometry on bending angle and that of multiple laser irradiations on bending rate were also investigated. Bending angle was found to be influenced by the work-piece geometry. Bending angle increased with the number of laser scans, but the bending rate decreased. Metallurgical changes at the laser irradiated zones of the laser formed samples, that is, micro-structures and micro-hardness were also studied using scanning electron microscope and Vickers’ micro-hardness tester, respectively. Microstructures were found to be refined and micro-hardness of the bent zone got improved due to the laser forming.

Beschreibung: Carbon emission has become a recent global concern for green manufacturing. Production is one of the main sources of carbon emission. As the design of a product determines over 70 % of its life cycle costs, with extensive impacts on the environment, it is important to decrease the product carbon footprint in the product design stage. As the activity data is directly related to the mass of the product, the lightweight of product is a valid approach to low-carbon footprint. However, the existing lightweight design method primarily takes structure or material into consideration without the consideration of environmental factors. The product lightweight design under the low-carbon footprint constraint is proposed in this paper, which serves low-carbon footprint as an important benchmarking for product performance. This paper then presents a general lightweight design for product low-carbon footprint through structural optimization. The design of a cold heading machine is used to demonstrate the proposed methodology.

Beschreibung: Titanium alloys are widely utilized in aerospace, automotive, biomedical and chemical engineering, etc., thanks to their excellent combination of high-specific strength, fracture, corrosion resistance characteristics, etc. However, titanium alloys are difficult-to-machine materials. Tool wear is one of the bottlenecks restricting their machining efficiency. A systematic study on the relationships among tool wear, chip morphology, and cutting vibration is inadequate. In this study, chip morphology and cutting vibration characteristics under different tool wear stages are examined using optical microscope, SEM, and vibration test system. The mechanism of tool wear in end milling titanium alloy is also investigated. Results indicate that with the progression of tool wear, the chip segment degree becomes more and more serious. The mechanism for this phenomenon is probed. Tool wear progression enlarges the cutting vibration which causes the friction force on tool/chip interfaces to increase, and this aggravates chip edge wear accordingly. On the contrary, the increase of chip segment degree induces the progression of cutting vibration and tool wear. Therefore, the aim of the present research is to investigate the sophisticated relationship. This will benefit for improving cutting efficiency and guaranteeing machining quality in end milling titanium alloy.

Beschreibung: Magnetic pulse cladding (MPC), a new technology, is proposed in this study to fabricate often utilized bi-metal tubing in engineering applications with an outer tubular component consisting of structurally strong material and an inner tubular layer of corrosion-resistant material. The MPC process includes an innovative feature that allows the outer and inner tubes to electromagnetically bond together by a sequential expansion process to form a mechanical bond between the tubes at the interface. The MPC process was experimentally arranged to produce an Al/Fe bi-metal tube with an outer carbon steel tube and an internal aluminum tube. A mechanical test was then applied to characterize bonding strength of the Al/Fe bi-metal tube. Significant process parameters including discharging voltage, radial gap, and feeding length were identified based on bonding strength influence. Overall feasibility was demonstrated for the MPC process in electromagnetic expansion pattern in the production of bi-metal tubing.

Beschreibung: Effective approach of collecting, transmitting, and handling complete product manufacturing information during machining process is necessary for realizing high efficiency manufacturing. In this paper, the architecture and implementation of closed-loop machining system (CLMS) is discussed and the method of realizing machining process control is introduced. An integrated information flow is built based on object-oriented description method to transfer complete product manufacturing information in CLMS. The functional and informational model of CLMS is established by using integration definition method. Online and real-time machining process control is implemented on an open STEP-NC controller which is collecting and analyzing information of machining process condition and inspection results during machining process. The software kernel of CNC controller implemented on a computer platform integrates with machine tool, sensors, and probe for real-time data collecting and online inspection. Finally, test parts are machined and inspected to verify the proposed machining process control method and open STEP-NC controller.

Beschreibung: An advantage of electron beam melting (EBM) additive manufacturing technology is the ability to process high-melting temperature, refractory, and/or reactive materials. This research focused on the processing of high-purity niobium precursor powder using EBM technology primarily for the freeform design and fabrication of next-generation superconducting radiofrequency (SRF) cavities. SRF accelerating cavities have been used in particle accelerators for over 35 years and are used in today’s leading applications in high-energy and nuclear physics. Procedures were developed and employed in this research to successfully fabricate high-density niobium parts (〉99 % relative density) with a thermal conductivity of ~50 W/m-K that were evaluated mechanically (140 ± 14 MPa yield strength and 225 ± 11 MPa ultimate tensile strength) and compared to wrought reactor-grade niobium (135 ± 17 MPa yield strength and 205 ± 17 MPa ultimate tensile strength). Re-engineered SRF cavities were successfully fabricated whose complex design was intended to overcome nonuniform Lorentz forces during operation. The fabrication of niobium using EBM suggests that similar procedures from this research can be applied to successfully fabricate other refractory materials such as niobium alloys as well as highly conductive materials such as copper.

Beschreibung: This paper outlines an Internet of Things (IoT)-based collaborative framework which provides a foundation for cyber physical interactions and collaborations for advanced manufacturing domains. A general framework for collaborative manufacturing is proposed followed by a discussion of such an IoT-based framework for the domain of micro devices assembly. The design of this collaborative framework is discussed in the context of cloud computing as well as the emerging Next Internet which is the focus of recent initiatives in the USA, EU, and other countries. The data/information exchange between the various software and physical components is modeled using the engineering Enterprise Modeling Language (eEML), which provides a structured foundation for designing and developing this IoT-based collaborative framework. The key cyber physical components and modules are described followed by a discussion of the implementation of this framework.

Beschreibung: The longevity of hard alloy indexable cutting inserts used to cut metal parts is significantly related to their proper geometric design. Such a relationship is outstanding in an intermittent cutting scenario. One solution is to use a strengthened cutting insert with a negative chamfered edge. This method has proven to be effective in avoiding chipping and brittle fractures. However, it does have other effects, like a larger cutting force and a higher cutting heat. In the present research, a set of intermittent cutting experiments were conducted through combinations of two grades of hard alloy indexable inserts and multiple geometric parameters of cutting edges. A three-dimensional dynamometer and a high-speed camera were used to monitor and collect data on the impact and cutting force during the process. A study over the strengthening mechanism of the negative chamfer to the cutting insert was conducted using statistical analysis, which revealed the influence of those geometric parameters of cutting edges on the insert’s lifetime. Further, it gave a quantified relationship between the negative chamfer parameter and the feed. This conclusion serves as both data and technical support for the design enhancement of hard alloy indexable inserts.

Beschreibung: Orthogonal turn-milling is a novel machining process with the advantages of better surface quality, improved process stability, and higher machining efficiency compared to conventional turning. Chip formation in the turn-milling process plays a significant role in cutting force, tool life, and chatter stability. This paper presents an experimental study on the 3D chip morphology properties during orthogonal turn-milling of Al6061-T6. The effects of cutting parameters on turn-milling chip length and thickness were examined and discussed. The multi-surfaces (including free surface, back surface, and cross-section surface) of turn-milling chip were characterized to understand the mechanism of chip morphology formation. The mixed continuous-and-segmented chips in a single cut and its slipping properties were observed, and the shear band of serrated chip and its ductile fracture property were analyzed. The microhardness variation of turn-milling chip was investigated under different machining parameters. The shear band as well as the profile surface of chip shows increased hardness. This experimental study presents the insight in evaluating the cutting mechanism of turn-milling process and provides guidance for choosing optimum cutting conditions.

Beschreibung: High-accuracy contouring error estimation is the premise of effective contouring error control. However, two key factors make it complex to estimate contouring error for multi-axis machines with rotary axes: the nonlinear kinematics and the synchronization requirement of the tool tip position and tool orientation. This paper proposes a generalized online estimation algorithm of multi-axis contouring errors for CNC machine tools with rotary axes. The nearest reference tool pose to the actual one is searched at first, and then the corresponding contouring error components on each axis are estimated by using linear ratio estimation, where the tool tip position and tool orientation are naturally synchronized to one same pose on the desired trajectory. The advantage of the proposed contouring error estimation algorithm is that only the interpolated reference poses and drive commands are needed in the calculation, which increases the generality of the algorithm to different trajectory types and machine topologies. On the other hand, the calculation load is reduced when compared with existing iterative multi-axis contouring error estimation approaches. Simulation results on both five- and four-axis machines show that the proposed contouring error estimation algorithm can estimate axis components of contouring errors with high accuracy. Experiment results on an in-house developed five-axis experiment platform verify the effectiveness of the proposed algorithm.

Beschreibung: Heat flux changes in grind-hardening process resulting in uneven distribution of grind-hardening layer depth, making it more difficult to produce a hardened layer in the grinding cutting-in and cutting-out area, leading to uneven distribution of the hardening layer depth in grinding stable region. This paper firstly studied the grinding force. Secondly, grinding distortion is analyzed by thermal–mechanical coupling numerical analysis. The grinding distortion makes the actual grinding depth deeper. According to the distortion, the actual cutting depth can be concluded. The actual cutting depth affects the variation of grinding force. Thirdly, the relationship among grinding force, grinding distortion, and the distribution of the hardening layer depth is presented in the paper. At last, variable grinding cutting depth to control grinding force is put forward to improve the uniformity of the distribution of the hardening layer and is verified by experiment.

Beschreibung: Fused deposition modeling (FDM) is one of the most popular additive manufacturing technologies for fabricating prototypes with complex geometry and different materials. However, current commercial FDM machines have the limitations in process reliability and product quality. In order to overcome these limitations and increase the levels of machine intelligence and automation, machine conditions need to be monitored more closely as in closed-loop control systems. In this study, a new method for in situ monitoring of FDM machine conditions is proposed, where acoustic emission (AE) technique is applied. The proposed method allows for the identification of both normal and abnormal states of the machine conditions. The time-domain features of AE hits are used as the indicators. Support vector machines with the radial basis function kernel are applied for state identification. Experimental results show that this new method can potentially serve as a non-intrusive diagnostic and prognostic tool for FDM machine maintenance and process control.

Beschreibung: In practical applications of multivariate sliding window (SW) control charts, a considerable amount of difficulty lies in selecting parameters related to the window size and to the disposal of past observations. Although widely used for pattern recognition problems, to the best of the authors’ knowledge, there have been no comparative analyses of the efficiencies of multivariate SW schemes and more traditional and easy-to-apply control charts, such as Hotelling’s T 2 and the multivariate exponentially weighted moving average (MEWMA) control charts. The present work applies a transformed statistic called confidence control chart (CCC), which standardizes all the control charts in the 0–01 interval to improve visualization, and comparisons are made in terms of the average run length (ARL). Therefore, the purpose of this paper is to present a simulation study to compare the inertial effect of estimating the actual mean vector through the SW and the MEWMA schemes. Three types of SW schemes were tested, including uniform, linear, and exponential weights. In addition to providing equivalences between the smoothing parameter of the MEWMA method and the window sizes for the bivariate case, the results show that multivariate SW schemes suffer from the inertial effect more than MEWMA charts. In this sense, the user is encouraged to apply both control charts to avoid detection delay.

Beschreibung: This article presents the work on wear-resistance coatings (WRC), formed on the working surfaces of HSS tools, in order to increase their efficiency. The wear-resistant complex includes nitride layer, which increases the plastic strength of the HSS tool cutting wedge and cutting tool wear resistance, as well as a three-layer nano-structured composite coating that increases tool life. The equipment for the processes of ion nitriding in the gas plasma and the formation of nano-structured multi-layer composite coatings in the filtered metal-gas plasma cathode vacuum arc discharge has been developed. Particular attention was paid to the regularities in the formation of the nitride layer and optimization of its parameters and structure, together with the study of the properties and structure of functional coating layers, depending on the parameters of the deposition process. The parameters of the combined cathodic vacuum arc processing (CCVAP), provides minimum intensity of tool wear during the cutting tests. Sample of coated tools were used to conduct a certification of the developed WRC. This allowed determining the optimal parameters WRC that provided the maximum increase in tool life for a variety of cutting conditions. The outcomes are compared with uncoated HSS tool and standard commercial coatings.

Beschreibung: Joining of multimaterials is a major issue for several industrial applications where the combination of individual material properties increases component performance. The objective of this experimental study is to assess the laser weldability of NiTi to Ti-6Al-4V. Dissimilar welds were performed on 1-mm-thick plates with a high-power fiber laser with different heat inputs to control the cooling rate. Fracture was always observed in the weld metal in a solidification cracking phenomena. Scanning electron microscopy with EDS was performed to analyze the fracture surfaces. Solidification cracking was observed in the fusion zone associated to Ti 2 Ni formation in two distinct fracture morphologies: brittle transgranular cracking in the Ti 2 Ni regions and dimple intergranular failure along the solidification dendrites. Thus, autogeneous welding of these two materials is difficult due to intermetallics formation and filler materials or interlayers are needed to prevent the formation of brittle intermetallics.

Beschreibung: Reconfigurable manufacturing machines are designed to allow manufacturers to readily adapt to changing circumstances. This adds a new dimension to the process-planning problem, as the machine structure is not constant. A comprehensive set of reconfiguration management assessment tools and methods must be introduced to assist in developing the most appropriate process change strategies for a given set of circumstances based on the machine structures, control capabilities, and the skill levels and availability of shop personnel. Therefore, the goal of this research is to develop methods to assess the machine configuration/reconfiguration compatibility characteristics for alternative process strategies. The methods must be adaptable to suit a variety of environments and present results that are readily understood by all actors. Systematic, matrix-based techniques for assessing product and process complexity are introduced as well as a methodology to assess the suitability for CNC machine tool configurations with respect to a process plan, which considers the candidate machines’ physical and functional characteristics to determine its suitability. The resulting candidate machines are subsequently assessed to consider the process transition complexity issues utilizing an extension of a manufacturing complexity analysis framework used to evaluate product and process complexity. Case studies are presented to illustrate the merits of the proposed methodology.

Beschreibung: The present article offers a modified method of friction stir process combined with ultrasonic vibrations in order to reinforce polyamide 6 (PA 6) using multi-walled carbon nanotubes (MWCNT). For this purpose, ultrasonic-assisted friction stir process and simple friction stir process were performed to distribute the MWCNT particles among the PA 6. Field emission type of scanning electron microscopy, X-ray diffraction, Vickers’ micro-hardness, and visual inspection were used to evaluate and compare properties of the fabricated nano-composites. According to the findings, increase of traverse speed leads to increase of the stir intensified by the energy imposed by ultrasonic vibrations during ultrasonic-assisted friction stir process (UAFSP). On the other hand, energy imposed by ultrasonic vibrations accelerates nano-composite fabrication process without affecting dispersion, homogeneity, and hardness. In other words, nano-composite could be fabricated by higher traverse speed without reduction of stirring during UAFSP.

Beschreibung: An underground reservoir is an effective way to solve water resource problems, such as uneven water distribution and shortage. Based on the groundwater overdraft status in Beijing, the hydrogeologic conditions in Miyun–Huairou–Shunyi (MHS) area, and the excess water of Middle Route Project of South-to-North Water Transfers in Beijing, 3D strata spatial geological structure models are developed by software Groundwater Modeling System (GMS). Different types of water levels and their corresponding feature storage are illustrated to assess the storage capacity of the underground reservoir. The storage capacity is analyzed in the MHS area according to the models and water levels. The total storage is about 31.11 × 10 8  m 3 . The dead storage is approximately 15.07 × 10 8  m 3 , and the beneficial storage is approximately 16.05 × 10 8  m 3 . Results present important reference for the construction of underground reservoir in Beijing. The construction is important in solving the serious water shortage problem in Beijing.

Beschreibung: In this paper, the correlations between the different measurements of rock brittleness (i.e., B 1 , B 2 , B 3 , and BI ) and the penetration rate (PR) of tunnel boring machine (TBM) through Zagros long tunnel were evaluated. According to the results of simple regression analyses, there was no correlation between the penetration rate of TBM and the brittleness of B 1 , but stronger log-linear correlations have been observed between the penetration rate of TBM and the B 2 , B 3 , and BI brittleness indices. As part of the present study, correlations between some of rock mass classification systems (RQD, RMR, GSI, Q , and Q TBM ) and penetration rate of TBM have been investigated. The results of simple regression analyses showed that the first four rock mass classification systems did not exhibit a good correlation with the TBM penetration rate, but the Q TBM had strong correlation with that. Multiple linear regression (MLR) analyses were applied for estimating the TBM penetration rate based on three properties of the rocks (porosity ( n ), brittleness of B 3 , and elastic modulus ( E ) of intact rock) and rock mass quality system ( Q ). Also, in this study, artificial neural network (ANN) analyses were applied on the data to develop predictive models for the penetration rate of TBM from porosity, brittleness of B 3 , elastic modulus, and Q values. The comparison of the models produced from ANN and MLR analyses using the coefficients of determination showed that the ANN models for predicting the TBM penetration rate were more reliable than the MLR models.

Beschreibung: This paper presents the design and 3D numerical modeling of the temporary support system for the twin tunnels in the transition zone of the Esfahan subway project. Ground movements caused by tunneling beneath urban areas can have a significant impact on adjacent structures and therefore require consideration when choosing the excavation method and the type of support system. Due to the old buildings in the historical city of Esfahan, this research requires parametric studies for the use of simulation techniques. This paper focuses on 3D stability analysis and design of the support system required to control the critical strain and ground movement due to excavation of the transition area of the twin tunnels in the Esfahan subway project. A numerical model is developed to estimate the excavation effects on the critical strain and ground settlement and also the effect of reinforcement measures. In the 3D numerical model, a constitutive law characterized by the time-dependent stiffness and strength of the shotcrete is employed. Results show that the suggested support is sufficient to control the settlement and critical strain due to tunneling. Comparison between the 2D model prediction and the results of corresponding 3D model indicates that the conformity between 2D and 3D analysis results decreases in the transition region. One of the most useful methods to determine the induced seismic loads, the use of time-history dynamic analysis is usually done for major projects. In this paper, for the twin tunnels of subway, Fast Lagrangian Analysis of Continua (FLAC) software is used for this purpose.

Beschreibung: Iraq Geological Survey carried out geological investigations on a limestone deposit at SW Najaf area during 2006–2007 to be utilized in Kuffa Cement Plant. Large reserve is estimated with good quality enough to produce 2.3 million tons/year of Portland cement for more than 50 years. The next stage is to use the geological information to prepare mining geological study needed for extractive processes. The results of chemical analysis of samples are used for quantitative mining condition study and estimating industrial reserve by programs RW2004 and RW2006. This procedure resulted in some essential geological and mining recommendations.

Beschreibung: This paper suggests that the fungal fruiting bodies identified by Al-Ameri and Jassim ( Arab J Geosci 4:443–461, 2011 ) as Plochmopellinites (Figures 6–10) is a thecamoebian taxa Arcella discoides , likewise Miliolinites nivalis (Figures 6–14) is another thecamoebian taxa Centropyxis aculeata. This conclusion is primarily based on the remarkable morphological similarity between these specimens illustrated and described by Al-Ameri and Jassim ( Arab J Geosci 4:443–461, 2011 ) and the well-known thecamoebian taxa mentioned in this paper. These misidentified ‘fruiting fungal bodies’ were reported from the environments where thecamoebians are well known to inhabit. Thecamoebians are, by now, known to occur in the palynological slides and have become an important constituent of the non-pollen palynomorphs (NPP). Palynologists too study them as they are excellent proxies for Quaternary climatic and environmental changes.

Beschreibung: A lateritic soil profile formed on the top of the middle Miocene was identified in the south of the Eastern Desert of Egypt. It is located about 55 km south of Marsa Alam and far about 3 km from the Red Sea coast. The mineral identification of samples was carried out using X-ray diffraction (XRD) and scanning electron microscope (SEM). The study revealed the relative predominance of kaolinite and gibbsite beside iron minerals (hematite and goethite), evaporates (halite and anhydrite), carbonate (dolomite and calcite), quartz, and cryptomelane. Accessory minerals are represented by columbite, tapiolite, thorite, monazite, zircon, barite, atacamite, anarkite, romanchite, hemimorphite, cerussite, garnet, ilmenite, nickel, and flurorichterite. The geochemical data of the bulk samples reflect enrichment in SiO 2 , Al 2 O 3 , Fe 2 O 3 , Zn, Pb, Ba, Sr, As, Nb, Cu, and Zr. This lateritic soil shows high Uc/Th ratio indicating addition of uranium under suboxic to anoxic condition. The LREE predominance was over the HREE due to the presence of monazite mineral. Negative Eu anomaly confirms the saturated source rocks of these laterites.

Beschreibung: Based on distinct variations of textural characteristics, stratigraphical relationships and mineral composition of clastics sedimentary sequence (coarse aggregates) in west Sohag, Upper Egypt had been classified into six individual geological evolutionary stages. These stages were controlled mainly by geomorphology, paleo-climatic conditions, and regional and local tectonic events. In west Sohag, Upper Egypt, the suitability of the Oligocene–Pleistocene natural coarse aggregates have been examined in terms of pavement materials in a sub-base consideration. Depending on textual characteristics and mineral composition, these natural coarse aggregates indicated three distinct stages of geological evolution of the Egyptian Nile Valley. These aggregates are classified as well-graded gravels (GW) and distinguished by cubical shape with sub-angular to sub-rounded edges, as well as characterized by a relatively high abrasion resistance. This leads to a suitability of these natural aggregates in being used as a sub-base pavement course for higher shear strength, exhibiting a less fatigue life. The total estimated volume of these coarse aggregate is 2060.41 million m 3 . This volume of natural coarse aggregates can be dry sieved and crushed to produce base and surface pavement courses.

Beschreibung: This study addresses the effects of rock characteristics and blasting design parameters on blast-induced vibrations in the Kangal open-pit coal mine, the Tülü open-pit boron mine, and the Kırka open-pit boron mine. In this study, multiple vibration measurements have been conducted, and the related data have been analyzed and evaluated. Several artificial neural network (ANN) and regression models based on the same blasting design parameters, resistivity, and P-wave and S wave velocities of the surrounding rocks have been constructed to estimate the peak particle velocities and the frequencies of related blast-induced vibrations. The data derived from these models and the classical evaluations indicate that ANNs provide more reliable results than the other methods.

Beschreibung: Landmasses can be classified as “islands” or “continents” mainly by geological, rather than geographical, criteria but the classification is still a bit arbitrary. We are presenting a statistical method (a modified Korcak analysis) where the area distribution reveals an intrinsic classification of landmasses. Based on this analysis, one can separate island, subcontinents and continents using only a spatial or geographical criterion, the area. Although not completely, this classification gives more or less the same groups like the ones based on geological criteria.

Beschreibung: Eastern desert of Egypt is well-endowed with noble mineral resources that provide challenges for the future economy and development in Egypt. Such mineral resources are not yet well-mapped and fully understood; however, various geological maps are available. The newly advanced sensors of earth observations such as advanced space thermal emission and reflection radiometer (ASTER) images were functioned to map the lithology, the structural patterns and the alteration zones related to gold mineralization at the Fawakhir area, Central Eastern Desert of Egypt. Integration of band rationing and principal component analysis (PCA) clearly determined the lithological units of the study area. The alteration zones of the study area were efficiently mapped from the ASTER radiance data using reference spectra based on two supervised classification techniques including the spectral angle mapper (SAM) and spectral information divergence (SID). Field visits and laboratory microscopic examination of thin and polished sections were used for validating the process. The final resulted map of the alteration mineral zones consists of sericite, clay minerals, quartz, carbonate, and pyrite. Auto-detection of the structural lineaments, which are zones of deformation and fracturing that implies secondary porosity, was mapped from the satellite image. These structures represent significant pathways for migration of hydrothermal solutions, which influence the creation of the alteration zones and become potential zones for mineral resources. The spatial analysis showed the high correlation between the density of lineaments and the occurrence of the alteration zones, which represent high probability of the presence of gold deposits that validated against the old gold mines.

Beschreibung: Phosphorus (P) removal in a bioretention system has been highly variable. In this study, we investigated the potential application of sludge pyrolysis residue, which was prepared from sludge pyrolysis, for adsorption of P from a bioretention system. Kinetics result suggested that the P adsorbed on sludge pyrolysis residue was faster than that of two soils, and both the surface and intraparticle diffusion were the rate-controlling steps for the adsorption. All adsorption isotherms were highly nonlinear and fitted well by the Langmuir model in comparison to the Freundlich model. The maximum adsorption capacity of P by sludge pyrolysis residue reaches 1,250 mg/kg at an initial concentration of 100 mg/L. Batch adsorption experiments and post-adsorption characterization results indicated that the adsorption was mainly controlled by both the precipitation and surface deposition mechanisms. The presence of Al, Fe, and Ca in sludge pyrolysis residue can facilitate the P adsorption. The release of P adsorbed on sludge pyrolysis residue is negligible because of a strong interaction between P and Al, Fe, and Ca in sludge pyrolysis residue. The findings of this study suggested that sludge pyrolysis residue could be used as an optimal filter medium to improve the removal performance of P in a bioretention system.

Beschreibung: The Alut 1:100,000 sheet is located in the Sanandaj-Sirjan structural zone, NW Iran, which contains Au-Ag (Cu) mineralization. The aim of this research is to separate geochemical anomalies using concentration-number (C-N) multifractal modeling based on stream sediments and lithogeochemical data. Results obtained from the C-N method indicated the main anomalies of Au, Ag, Cu, and As accumulated in the central and eastern parts of the area which are associated with meta-volcanic and granitic rocks. Correlation between the elemental highly intensive anomalies and geological particulars consisting of alteration zones and faults revealed that the main Au anomalies are in the central and eastern parts of the Alut 1:100,000 sheet.

Beschreibung: The Gurpi Formation is a well-known source rock in the Zagros basin, which stretches from northeast to southwest Iran. Sequence stratigraphy was done based on the integration of evidence derived from palynological proxies and foraminiferal data. According to sequence stratigraphy, seven time lines including four sequence boundaries of type II and three maximum flooding surfaces with a resolution varying from 1 to 5 MY and three complete third-order sequences and one transgressive systems tract (TST) were differentiated. Maximum flooding surface of the first sequence in middle Campanian probably equates the 70-Ma maximum flooding surface (MFS) K175 of Sharland et al. (GeoArabia P: 371, 2001), and MFS of the second sequence in early Maastrichtian is correlated with the marked 68-Ma MFS (MFS K180) of Sharland et al. (GeoArabia P: 371, 2001) that is recorded in many parts of the Arabian Plate. Correlation with the Haq global eustatic curve, though uncertain because of the effect of local tectonics over the relative sea level changes, however, could be possible with the 69.5 Ma. Also, purple shales of the base of the Pabdeh Formation with a Thanetian age are defined as a MFS, correlation of which with the marked 58-Ma MFS (MFS Pg10) of Sharland et al. (GeoArabia P: 371, 2001) and with 56.5-Ma MFS of Haq seems likely. The relative sea level curve resulted in this study is not well in accord with the existing eustasy curves for the middle Campanian-late Paleocene indicating effect of tectonic on relative sea level changes during this period.

Beschreibung: The Triassic Chang-3 and Jurassic Yanan low-permeability reservoirs in the southern part of the Tianhuan Depression of the Ordos Basin, north-central China, were investigated using the quantitative fluorescence of reservoir sandstone grains and their hydrocarbon extracts. Values of quantitative grain fluorescence on extract intensity (QGF-E) are generally higher than 150 pc, indicating that oil and gas migration has taken place in the low-permeability tight sand bodies in the study area, so these sandstone strata were the main transport system of oil and gas migration. The values of QGF index and QGF-E in the Chang-3 subsection profile above 2168 m are higher than those below 2168 m; similarly, the two values in the Yanan formation profile above 1849 m are higher than those below 1849 m, indicating that the oil–water contacts of the Chang-3 subsection and Yanan Formation in the study area are 2168.0 and 1849.0 m, respectively. The results of total scanning fluorescence for hydrocarbon extracts from the Chang-3 subsection and Yanan Formation show that the extracts contain low aromatic hydrocarbon and are mature. Our results demonstrate that QGF and QGF-E methods are very effective in understanding the properties and accumulation process of hydrocarbon in low-permeability tight reservoir.

Beschreibung: More than 15,000 geological disasters occurred in areas affected by the Wenchuan earthquake. Among these regions, the Mujialiang collapse was obtained as the research object in this study. The motion characteristics of the rolling, bouncing, curveting, and crashing of dangerous rocks in the caving process were evaluated using physics theory. Results show that the rocks of the Mujialiang collapse were fractured and cracked after the earthquake and can easily caved under rainstorm and aftershock. In addition, vegetation conditions along the motion path promoted the accelerated movements of dangerous rocks. The velocity of dangerous rocks reached 9.05 m/s upon arriving on the slope platform, thus endangering the houses within the area. Therefore, management projects are necessary to ensure safety of the residents in the Mujialiang ditch.

Beschreibung: Geochemical and hydrogeochemical studies were conducted to assess the origin and geochemical mechanisms driving the fluoride enrichment in groundwaters of semiarid regions in Central India. The study region is geologically occupied by Precambrian rocks (granites, pegmatites, gneisses, schists, etc.) where groundwater occurs under unconfined condition. Majority of the groundwater locations did not meet the potable water criteria as they contained excess fluoride (〉1.5 mg/l). The greater concentrations of fluoride were recorded in the monsoon followed by post-monsoon and pre-monsoon. Ionic composition and hydrogeochemical facies revealed the dominance of carbonate weathering and alkalinity that favors high dissolved fluoride in groundwaters. The values of dissociation constant showed slow weathering of fluorite and fast weathering of calcite in the study area. Rainfall shifted the unsaturated to saturated values of SI C and SI F in the monsoon. The factor analysis and saturation indices revealed geogenic origin of fluoride, a condition responsible for perennial fluoride problem in the study region.

Beschreibung: The large amounts of phosphate fertilizers which are used in agriculture activities in Egypt lead to the contamination of large quantities of soil surrounding the agricultural fields. Also, the use of traditional flood irrigation method makes the problem more worse. An extensive laboratory testing program is carried out to determine the Atterberg limits, compaction characteristics, hydraulic conductivity, and shear strength parameters of clean and contaminated soils. Three types of soils are used including coarse sand, fine to medium sand, and silty clay. Batch tests are used to study the short-term effect of di-ammonium phosphate (DAP) contamination on the soil properties. Contaminated specimens are prepared by mixing the dried soil samples with different di-ammonium phosphate concentrations of 5, 10, and 20 %. The results indicate a significant reduction in Atterberg limits and increase in hydraulic conductivity for silty clay soil with the increase of phosphate concentration. The change that is induced by chemical reaction in the micro-structure of the soil is studied by laser scanning microscope before and after soil contamination. For sand soil, γ dmax is significantly increased with the increase of DAP concentrations up to 5 % and slightly increased with concentrations from 5 to 20 % which indicates excess phosphate in the soil. However, the general trend of hydraulic conductivity is towards reduction. In addition, the friction angle of two sand samples decreases about 10 % due to the increase of DAP concentration up to 20 %. For silty clay, the reduction in cohesion is about 20 % and the increase of friction angle is about 10 % with the increase of DAP up to 20 %.

Beschreibung: With the increasing impact of climate change and anthropogenic activities, drought happens in more areas with higher frequency. In this paper, we calculate the return period and the drought risk in China based on the monthly PDSI, the Palmer Drought Severity Index, data over 188 stations from 1901 to 2010. We use the theory of runs to identify the drought duration and severity. We adopt the kernel density estimation to obtain the marginal distribution function, and the Gumbel Copula function to obtain the joint distribution function. The results show that the return period of the joint distribution for the drought duration and severity can be regarded as the extreme condition of the return period of the marginal distribution for the single factor such as the drought duration or drought severity. Under the same drought severity, the return period of the joint distribution is increasing with the prolonging of the drought duration, and it approaches to the return period of the marginal distribution of the drought severity. Under the extreme drought situation, Haihe River Basin, Huaihe River Basin, Songliao River basin, and rivers in the northwest China have a higher drought risk in future 50 years. The drought risk value in China is increasing with the prolonging of predicting time.

Beschreibung: Gully systems develop widely in the Yuanmou Dry-hot Valley. Based on the Scheidegger method and the non-parametric method, this study interpreted 1599 gullies using a DEM with a scale of 1:50,000, and remote sensing images were photographed by QuickBird. The objectives are to explore the regularity that is shown in the distributive direction of the gully system and to understand the factors (including aspect, slope, and the neotectonic stress field) that control the distributive direction of the gully system. The results show that (1) the maximum “dominant” direction of the overall, the third and fourth order, the east, above 1400 m gully are 270°; the “dominant” direction 270° has relative superiority. So 270° is the “dominant” direction of the gully system in the Yuanmou Dry-hot Valleys area. (2) The slope of 38° is the threshold value which separates the overall slope range. When the slope is in the range 0–38°, the slope is the dominant factor; when the slope is in the range 38–59°, aspect is the dominant factor. So, with the increase of slope, 38° is the threshold value, and the dominant topographic influence is changed from slope to aspect. (3) The direction of the compressive stress field, 157.5°, is proven not to conflict with the directions 146.3, 157.5, 169, and 180° that are the principal compressive stresses calculated for the gully system. So the collision and extrusion of plates can form fracture surfaces which provide a favorable condition for the development of drainage and gullies. The distributive direction of the gully system is comprehensively affected by the neotectonic stress field, the terrain, and other factors. Therefore, the study of the distributive direction of the gully system not only enriches the content of morphology on the landform but can also be the basis for the evolutional direction of the gully system that is effectively predicted in the study area, and it provides scientific guidance for industrial and agricultural production layout and the construction of infrastructure.