ALBERT

Beschreibung: The possibility of predicting the droplet size distribution from the particle size distribution was investigated. For that purpose, suspensions of different types of materials were dried in a laboratory-scale spray drier. Drying of suspensions was performed with different sizes of two-fluid nozzles. Droplet size distribution was evaluated from the data obtained for spray drying of bismuth molybdate suspension. The method was validated experimentally with other tested materials. Investigated systems involve processes of drying, crystallization, and coating. The proposed methodology can be applied when nonagglomerated particles, spherical particles, or spherical agglomerates were obtained by spray drying. Spray drying is a unique drying process since formation of solid phase and drying occur simultaneously. Droplet size distribution produced by a two-fluid nozzle during spray drying of bismuth molybdate suspension was evaluated simply from the particle size distribution. The proposed methodology enables prediction of the particle size distribution obtained by spray drying.

Beschreibung: The influence of vibration parameters on the segregation phenomenon of a binary mixture in a vibration fluidized bed is investigated. Initially, the mixture composed of spherical balls with different densities but same diameter is in a perfect mixing state in the bed. The motion of particles is simulated based on the discrete element method. The effects of friction coefficient, vibration frequency, amplitudes, and gas velocity are analyzed. The coefficient of segregation to the degree of particle segregation is calculated for different operating conditions. The segregation degree in the vibration fluidized bed is found to be higher than that in the bed without vibration. The curve for the segregation degree exhibits a single peak value which represents the optimal segregation result. The impact of vibration on gas phase- and particle flow is not yet clarified due to the complex motion of particles in vibrated fluidized beds. Discrete particle simulation is used to investigate the segregation behavior of binary mixtures in a fluidized bed. The effect of vibration parameters and suitable operating conditions for segregation, particle distribution, and particle motion are evaluated.

Beschreibung: The effects of a turbulence-generating grid on fluid mixing and a passive chemical reaction are experimentally investigated in a liquid shear mixing layer under a nonpremixed condition. The grid is installed at three streamwise locations to find the optimal location to promote the chemical reaction. The results show that the grid generates disturbances at small scales that enhance fluid mixing and the chemical reaction. However, the turbulence intensity and mass diffusion in the mixing layers with the grid decrease rapidly and become even smaller than those in the mixing layer without the grid in a downstream region. Therefore, in the present study, the chemical production is maximized when the grid is installed at where the flow is turning to a developed mixing layer. Installation of a turbulence-generating grid is advantageous to promote fluid mixing and chemical reaction in a free shear flow in which the reactive fluids are introduced under a nonpremixed condition. Special attention is needed regarding the location of the grid to maximize the promotion effect since it could be better to install it in the downstream region rather than the upstream region.

Beschreibung: Bubble splitting in 2D gas-solid freely bubbling fluidized beds is experimentally investigated using digital image analysis. The quantitative results can be applied for the development of a new breakage model for bubbly fluidized beds, especially discrete bubble models. The variation of splitting frequency with bubble diameter, new resulting bubble volumes, positions, and also the assumptions of mass and momentum conservation for bubbles after breakage are studied in detail. Small bubbles are found to be more stable than large ones and nearly all mother bubbles split into two almost equally sized daughter bubbles. The momentum of gas bubbles in the vertical direction remains approximately constant after breakage, whereas that of bubbles in the horizontal direction changes with no clear trend. The effect of fluidizing gas velocity in breakage frequency is also examined. The behavior of gas bubbles plays a key role in heat- and mass-transfer operations in fluidized beds. Bubble splitting for Geldart B-type particles under varying conditions was investigated in a pseudo-2D gas-solid fluidized bed by digital image analysis. The quantitative results can facilitate the development of new breakage models for bubbly fluidized beds and are particularly relevant for discrete bubble modeling.

Beschreibung: For the application of microreactors in industrial processes, more scaling-up strategies are still required except of the original concept, the numbering-up. A more maneuverable and economic approach, combining both similarity-up and numbering-up, is introduced as an example for an innovative strategy. CFD simulation is also applied to assist analysis and optimization of fluid distribution. Based on this concept, named similarity-up + numbering-up + simulation, a pilot-plant microsieve dispersion minireactor used to proceed the reaction of cyclohexanecarboxylic acid and oleum is designed and tested experimentally. With the contribution of similarity-up, the treating capacity of the core unit is significantly increased. Ten parallel units are integrated to form a correspondingly enhanced capacity of the microreactor which exhibits low pressure drop, stable operating performance, and excellent main product selectivity. For industrial applications of microreactors, more flexible and economic scaling-up strategies are required. A scale-up approach for a microsieve dispersion reactor is proposed, combining similarity-up and numbering-up of the core unit with CFD simulation-based device structure optimization. Low fabrication cost, low pressure drop, and excellent main product selectivity can be achieved by this strategy.

Beschreibung: A new design of conjugated heat transfer in double-pass parallel-plate laminar countercurrent operations of power law fluids under wall isoflux was investigated experimentally and theoretically. The analytical solutions were obtained with a superposition model by introducing an eigenfunction expansion in terms of a power series for the homogeneous part and an asymptotic solution for the inhomogeneous part. The influence of the power law index on the average Nusselt numbers with the various design and operating parameters is also delineated. The theoretical predictions of the experimental results are represented graphically. The heat transfer performance was considerably improved when compared with a single-pass parallel-plate heat exchanger (without inserting a solid separator sheet). Suitable adjustments of the solid separator sheet position can effectively enhance the heat transfer efficiencies for such a recycling double-pass device, as compared with the efficiencies of single- and double-pass devices.

Beschreibung: In order to study emulsification phenomena, devices generating well-defined flow conditions are essential. Thus, emulsification of drop collectives under laminar shear flow is commonly performed in cylindrical Couette or Searle devices. In these devices, the flow conditions in the shear gap and in the volume underneath the rotor are often different, which can lead to inhomogeneous product properties and may complicate sample taking. Here, a novel cone-cone shear cell is presented to study emulsification processes. The flow inside the device is examined using numerical simulations. The numerical simulations indicate that simple shear flow is realized all over the sample volume in the cone-cone shear cell. The experimental results show that the drop breakup in the cone-cone shear cell is equivalent to the breakup under simple shear realized in the shear gap of a conventional device, i.e., the Searle device. Critical capillary numbers are calculated from the experimental data and show breakup behavior as predicted by single-drop experiments. Thus, the cone-cone shear cell proved to be suitable to study emulsification mechanisms in simple shear flow. Emulsion-based products are widely used in the food, chemical, and pharmaceutical industries. A novel cone-cone shear cell to study emulsification characteristics is described. The flow conditions inside the shear cell are validated via numerical simulations and experimental results.

Beschreibung: Hydrocracking of a bitumen-derived asphaltene over NiMo/ γ -Al 2 O 3 was investigated in a microbatch reactor at varying temperatures. The molar kinetics of asphaltene cracking reaction was examined by fitting the experimental data. Below a defined temperature, the molar reaction showed the first-order kinetic feature while at higher temperatures secondary reactions such as coke formation became significant, causing deviation of the reaction behavior from the proposed first-order kinetic model. Selectivity analysis proved that dominant products varied from gases to liquids to gases with increasing temperature, shifting the dominant reaction from C–S bonds cleavage to C–C bonds cleavage. Catalytic hydrocracking could be a proper choice for asphaltene upgrading but the reaction conditions still need to be optimized. Hydrocracking of a bitumen-derived asphaltene over a NiMo/ γ -Al 2 O 3 catalyst in a microbatch reactor at varying temperatures was analyzed. The molar kinetics of asphaltene cracking reaction was evaluated by fitting the experimental data.

Beschreibung: Two different types of metals (Cu and Ni) and the effect of CeO 2 addition to produce a CeO 2 -ZrO 2 co-supporter were investigated through the water-gas shift (WGS) reaction. It was found that the WGS activity could be enhanced with CeO 2 addition. At relatively high temperature, Ni-loaded catalysts exhibited higher CO conversion while Cu-loaded catalysts demonstrated better performance at low temperatures. The stability and yield of the CO 2 and H 2 products of the Cu catalysts were higher than those of the Ni catalysts. These results may be caused by an irreversible adsorption of CO on Ni and the reverse WGS reaction occurring on the Ni catalysts. In situ diffuse-reflection infrared Fourier transform spectroscopy data suggests that the WGS mechanism likely proceeded via formate species. The water-gas shift reaction (WGS), as an alternative way to produce H 2 and convert poisonous CO into CO 2 , was carried out using Cu and Ni loaded onto CeO 2 -ZrO 2 as catalysts. The Ni-loaded catalysts exhibited higher CO conversion at high temperature while the Cu-loaded catalysts performed better at low temperature. The WGS reaction was found to occur via the formation of formate species.

Beschreibung: Power ultrasound is applied for cooling crystallization to control and modify the particle size and crystal habit of an active pharmaceutical ingredient, phenacetin. Operating parameters including sonication intensity and duration, solution concentration, and cooling rate are studied and compared. With respect to mean particle size, the effect of sonication intensity is most significant. In addition, the crystal habit of recrystallized phenacetin is modified substantially and shows an elliptic shape. Recrystallized phenacetin also provides an enhanced dissolution rate compared with the original sample. These results prove that ultrasonic crystallization is an efficient tool for controlling the solid-state properties of an active pharmaceutical ingredient. Ultrasonic crystallization is a promising process for controlling the different stages of crystallization. Cooling crystallization applying power ultrasound is adopted for recrystallization of a nonsteroidal anti-inflammatory drug, phenacetin. The mean particle size can be managed by adjusting sonication intensity and duration. Phenacetin crystals with a regular crystal habit and an elliptic shape are obtained.

Beschreibung: In a variety of reactions in the chemical industry, eggshell catalysts with a thin active layer are applied; they are often crushed for laboratory testing. The destruction of the shell can be avoided by a special reactor design. The presented advanced TEMKIN reactor is a further development of the reactor system for testing eggshell catalysts on the laboratory scale published by Temkin and Kul'kova in 1969. It is suitable for kinetic studies and for the detailed investigation of deactivation processes, as shown on the example of selective hydrogenation of acetylene. The advanced TEMKIN reactor is well suitable for testing of uncrushed industrial eggshell catalysts because of its defined flow pattern and excellent mass and heat transport properties. Because of its simple and robust design, all technical requirements are fulfilled for a fast, competitive, and accurate optimization of prototypes as well as already established catalysts for industrial applications.

Beschreibung: A bench-scale submerged membrane bioreactor (SMBR) was employed to treat vegetable oil plant wastewater with complete sludge retention. Treatment performance and membrane fouling of the SMBR were investigated. The system stably removed high amounts of total organic carbon, oil, and ammonia from vegetable oil wastewater and reduced the chemical oxygen demand, demonstrating the great potential of the SMBR in removing pollutants. The membrane fouling layer was not only governed by deposition of organic substances composed of extracellular polymeric substances like proteins, polysaccharides etc., and oil substances but also by inorganic elements. Organic foulants coupled to inorganic precipitation enhanced the formation of a gel layer and triggered severe membrane fouling in the SMBR. Treatment and disposal of vegetable oil wastewaters (VOWs) represents one of the principal problems for vegetable oil producing countries. A bench-scale submerged membrane bioreactor was applied to treat VOWs with complete sludge retention. Treatment performance and membrane fouling were investigated. The experimental results demonstrated the great potential of this membrane bioreactor in removing pollutants.

Beschreibung: Adsorption processes are frequently applied to separate traces of hazardous and toxic substances from gas streams. Hence, knowledge of sorption characteristics of these substances on standard adsorbents is essential. Sorption of hexanal and acetaldehyde from a nitrogen gas stream in trace concentrations on activated carbon and ordered mesoporous carbon-based adsorbents (CMK) is studied. A magnetic suspension balance and an attached gaschromatograph-mass spectrometer were used to analyze the sorption process both gravimetrically and spectrometrically. Both types of adsorbents show a higher capacity for hexanal than acetaldehyde. The activated carbon exhibits considerable differences in regard to desorption of hexanal compared to the mesoporous CMK. Information on sorption characteristics of hazardous substances is essential to design separation processes. Adsorption and desorption of the toxic acetaldehyde and the intensely odorous hexanal on activated carbon and periodic mesoporous carbon were studied. Magnetic suspension balances were used to analyze the sorption processes. Both adsorbents exhibit a higher capacity for hexanal than acetaldehyde.

Beschreibung: High-solids biomass slurries exhibit non-Newtonian behavior with a yield stress and require high power input for mixing. The goals were to determine the effect of scale and geometry on power number P 0 , and estimate the power for mixing a pretreated biomass slurry in a 3.8 million L hydrolysis reactor of conventional design. A lab-scale computational fluid dynamics model was validated against experimental data and then scaled up. A pitched-blade turbine and A310 hydrofoil were tested for various geometric arrangements. Flow was transitional; laminar and turbulence models resulted in equivalent P 0 which increased with scale. The ratio of impeller diameter to tank diameter affected P 0 for both impellers, but impeller clearance to tank diameter affected P 0 only for the A310. At least 2 MW is required to operate at this scale. High-solids biomass slurries are characterized by non-Newtonian behavior with a yield stress and high power input demand for mixing. A computational fluid dynamics model was developed to predict power requirements of non-Newtonian lignocellulosic slurry in an industrial-scale hydrolysis reactor with conventional mixing impellers. The lab-scale model was validated against experimental data and then scaled up.

Beschreibung: The effect of NaCl added in different quantities on thermodynamic properties, granulometric characteristics, and structure of glycine in a crystallization process was investigated. Solubilities of α - and γ -polymorphs in the presence of varying amounts of NaCl were analyzed. In order to examine the impact of the additive on granulometric properties of glycine, crystal morphology was examined by observing crystals under a scanning electron microscope. Crystal size distribution was determined by sieve analysis. By X-ray diffraction analysis, the critical concentration of NaCl at which the structure of glycine changed, could be defined. The purity of obtained polymorphs was confirmed by Fourier transform infrared spectroscopy. Interactions between additives and crystallizing phase influence crystallization processes. Batch-cooling crystallization of glycine with different amounts of added NaCl is described, causing changes in solubility, metastable zone width, supersaturation, final mass of crystals, granulometric properties, and structure. Process conditions for a conversion of α- into a γ- glycine structure are defined.

Beschreibung: Cryogenic air separation as the most important part of an integrated gasification combined cycle is a widely used operation unit for producing large quantities of high-purity oxygen and nitrogen. However, cryogenic distillation requires a large amount of energy due to the work needed to compress the air feed. An improved heat-integrated air separation column (HIASC) is proposed. The requirements of high-purity separation in the industrial cryogenic air separation process are achieved. An optimization model of the heat transfer coefficient ( UA ), a key parameter in column structure design and operation, is presented. The optimized UA value is obtained within the accepted value range reported in the international open literature, which ensures the practicability of the improved HIASC. An improved heat-integrated air separation column is proposed. With the new heat-integrated and thermally coupled structure, the pressure of the high-pressure column and the energy consumption decrease significantly compared with the conventional air separation column. The mathematic model and parameter analysis are presented. An optimization model for the heat transfer coefficient is proposed.

Beschreibung: Functional mesoporous Mo–SiO 2 materials were synthesized by a one-pot and facile room-temperature procedure, and characterized by X-ray diffraction, TEM, Raman spectroscopy, FT-IR, diffuse reflectance spectra, and BET analysis. The experimental results demonstrated that the mesoporous materials presented a high dispersion of molybdenum species and excellent catalytic activity for the removal of dibenzothiophene (DBT) without organic solvents as extractants. The catalytic performance on different sulfur-containing compounds was also investigated in detail. After recycling for eight times, the removal of the oxidation desulfurization system could still reach high values. GC-MS analysis detected the oxidation product of DBT. A mechanism was proposed for the absorptive oxidation process of sulfur compounds. The removal of sulfur compounds from petroleum is of utmost importance for stringent fuel specifications and environment pollution. Functional mesoporous Mo–SiO 2 materials were synthesized by a facile procedure and were characterized by a high dispersion of molybdenum species and excellent catalytic activity for the removal of dibenzothiophene under mild conditions without organic solvents as extractants.

Beschreibung: The level set method is combined with the concentration transformation method to solve the interphase mass transfer process. However, the artificial diffusion generated in the mass transfer convection term across the interface is inevitable, especially when large shape deformation is encountered at high Reynolds numbers. A semi-Lagrangian advection scheme is introduced to overcome this disadvantage. The methyl isobutyl ketone (MIBK)-acetic acid-water system is adopted to study the unsteady mass transport process accompanied with the Marangoni effect of a single deformable drop ascending in the infinite continuous phase. The predicted overall mass transfer coefficients agree with experimental data very well. The configuration of Marangoni convection is revealed and its effect on the interphase mass transfer process is investigated. The solute-induced Marangoni effect on an ascending drop driven by buoyancy is numerically simulated based on the level set method. The semi-Lagrangian convection scheme is introduced to eliminate the artificial diffusion. Compared with literature data, the present algorithm with the semi-Lagrangian convection scheme significantly suppressed the numerical diffusion and achieved much better predictions.

Beschreibung: The surface properties of solvent-based (SB) and water-based (WB) coatings and their impact on fouling during convective heat transfer of CaSO 4 solutions were investigated. Experiments demonstrated that the SB coatings had generally better non-adhesive characteristics, especially at higher values of the electron donor component since the deposits could easily be washed away. For the SB coatings, a longer induction period compared to those of untreated surfaces was observed and a significant reduction of the fouling rate could be achieved. Further analysis of surfaces revealed that SB coatings enhanced the acid-base repulsive force and thus reduced the deposit/solid adhesion energy. For the WB coatings, the Liftshitz-van der Waals attractive force plays a decisive role in the adhesion process due to the higher apolar component of the surface energy. Recent technological advances have given impetus in altering surface properties to mitigate fouling of heat transfer surfaces. The attempted coatings in this study demonstrated that they can extend the induction period of the fouling processes of CaSO 4 deposits by four times. This was but mostly due to their higher electron donor component of the surface energy compared to stainless-steel substrate.

Beschreibung: Ultrasonic hot embossing of polymers is an alternative to reduce fabrication costs of microreactors. An ultrasonic welding machine is used to melt a stack of thermoplastic foils and adapting them to a short-time milled aluminum mold showing the inversed design of the desired microfluidic cavities. Two micromixers were fabricated this way providing a low degree of axial dispersion and pressure loss. Stability analysis is successfully performed for a wide temperature range and high pressure. Mixing of colored aqueous solutions and neutralization reactions are implemented to both systems for defined volume flow rates and optically investigated via microscope. Reaction progress is automatically determined with a MATLAB script by reference to the consequential color change of the neutralization reaction with a color indicator. Typical mixing characteristics are identified for both mixers. Ultrasonic hot embossing of chemically resistant polymers as a simple and cost-effective fabrication method of microstructures and an optical analysis tool for tracing the progress of chemical reactions are introduced and evaluated. The simplicity of the fabrication method itself and good similarities of produced polymer micromixers with conventional ones made of other materials are pointed out.

Beschreibung: The existing screening and characterization systems for biocatalysts operate in batch mode, which could make catalyst selection and process development inaccurate when continuous operation mode is required in industry. A significant improvement of an innovative screening system based on miniaturized multiple membrane reactors formerly presented by the author is outlined, which enables continuous feeding of substrates and continuous removal of products. Although the presented screening system was originally designed for homogeneous enzymatic reactions, it can be used without further modifications for continuous catalysis with polymer-bound chemical catalysts or for quasi-homogeneous systems like reverse micelles. Currently available screening and characterization systems for biocatalysis are not sufficiently suitable for process description and scale-up of results to pilot- or full-scale reactors often operated in continuous mode. Hydrolysis of N -acetyl- L -methio-nine served as model reaction for an innovative continuous characterization system, implementing a precise dosing system.

Beschreibung: The synthesis of n -butyl levulinate, one of the most important biodiesel additives, by catalytic esterification of biomass-derived levulinic acid (LA) with n -butanol over modified H-ZSM-5 (micro/meso-HZ-5) in a closed-batch system is reported for the first time. The optimization of the reaction conditions such as the reactant molar ratio, the catalyst loading, the reaction time and the temperature was performed in view to maximize the yield of n -butyl levulinate. Micro/meso-HZ-5 was found to be the most efficient catalyst, with 98 % yield of n -butyl levulinate and a reusability for six cycles, which is higher than reported in the literature. A possible catalytic mechanism for the esterification reaction is also proposed. A second-order pseudo-homogeneous model with R 2  〉 0.97 confirmed that the esterification reaction is performed in the kinetic regime due to the high activation energy of 23.84 kJ mol −1 . The modified zeolite catalyst H-ZSM-5 (micro/meso-HZ-5) was used as heterogeneous acid catalyst in the esterification of renewable levulinic acid with n -butanol to produce n -butyl levulinate in a closed system. Micro/meso-HZ-5 turned out to be an efficient catalyst with 98 % yield of n -butyl levulinate and high reusability.

Beschreibung: ABSTRACT We present a technique that records transient changes in the fluorescence lifetime of a sample with spatial resolution along a one-dimensional scan. The technique is based on scanning the sample with a high-frequency pulsed laser beam, detecting single photons of the fluorescence light, and building up a photon distribution over the distance along the scan, the arrival times of the photons after the excitation pulses and the time after a stimulation of the sample. The maximum resolution at which lifetime changes can be recorded is given by the line scan period. Transient lifetime effects can thus be resolved at a resolution of about one millisecond. We demonstrate the technique for recording photochemical and nonphotochemical chlorophyll transients in plants and transient changes in free Ca 2+ in cultured neurons. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT Gonadotropin releasing hormone (GnRH) is a peptide that is conserved in both vertebrate and invertebrate species. In this study, we have demonstrated the distribution pattern of two isoforms of GnRH-like peptides in the neural ganglia and testis of reproductively mature male abalone , H. asinina , by immunohistochemistry and whole mount immunofluorescence. We found octopus (oct) GnRH and tunicate-I (t) GnRH-I immunoreactivities (ir) in type 1 neurosecretory cells (NS1) and they were expressed mostly within the ventral horn of the cerebral ganglion, whereas in pleuropedal ganglia they were localized primarily in the dorsal horn. Furthermore, tGnRH-I-ir were strongly detected in fibers at the caudal part of the cerebral ganglia and both ventral and dorsal horns of the pleuropedal ganglia. In the testis, only octGnRH-ir was found primarily in the granulated cell and central capillaries within the trabeculae. These results suggest that multiple GnRH-like peptides are present in the neural ganglia which could be the principal source of their production, whereas GnRH may also be synthesized locally in the testis and act as the paracrine control of testicular maturation. Microsc. Res. Tech. 77:110–119, 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: Robot in Laboratory. Copyright: Max Tactic – Fotolia.com.

Beschreibung: ABSTRACT Microtubules are important targets when studying potential anticancer agents since disturbance of these microtubule dynamics results in cell cycle arrest and cell death. 2-Methoxyestradiol is a naturally occurring metabolite that exerts antiproliferative activity and induces apoptosis. Due to limited biological accessibly and rapid metabolic degradation, several analogs were synthesized. This study investigated the antiproliferative influence of an 2-methoxyestradiol analog, (8R, 13S, 14S, 17S)-2-Ethyl-13-methyl-7, 8, 9, 11, 12,13, 14, 15, 16, 17-decahydro-6H-cyclopenta[a]phenanthrane-3, 17-diyl bis(sulfamate) (EMBS) on cell proliferation, morphology and apoptosis induction in a estrogen receptor-positive breast adenocarcinoma cells line (MCF-7), estrogen receptor-negative highly metastatic breast cell line (MDA-MB-231) and a non-tumorigenic breast epithelial cell line (MCF-12A). Spectrophotometry results indicated that EMBS exerted differential antiproliferative activity in the three cell lines. Cell growth of the breast adenocarcinoma and highly metastatic breast cell line reached a plateau effect at 0.4 μM after 24 h of exposure. Light microscopy and polarization-optical transmitted light differential interference contrast demonstrated compromised cell density, cells blocked in metaphase and the presence of apoptotic characteristics after EMBS exposure for 24 h in all three cell lines. Transmission electron microscopy and scanning electron microscopy revealed hallmarks of apoptosis namely the presence of apoptotic bodies, shrunken cells and cell debris in EMBS-exposed cells. This investigation demonstrated that EMBS does exert antimitotic activity and induces apoptosis contributing to elucidating the signal transduction of EMBS in tumorigenic and non-tumorigenic breast cell lines. Findings warrant in-depth analysis of specific targets in vitro and subsequent in vivo investigation for anticancer therapy. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT The sperm ultrastructure of the short-faced scorpionfly Panorpodes kuandianensis Zhong et al. was investigated using transmission electron microscopy. The spermatozoon is composed of a short head containing a bilayered acrosome and an elongate nucleus, a neck transition region, and a long flagellum. The acrosome consists of an acrosomal vesicle and a central perforatorium. The nucleus has two deep, U-shaped lateral grooves and its chromatin contains a series of parallel, regularly arrayed nuclear fibers. The barrel-shaped centriolar adjunct occupies the most volume of the neck region. The flagellum is helical for its whole length and is formed by an axoneme, two mitochondrial derivatives, a pair of accessory bodies, and peculiar accessory structures. The axoneme has nine accessory microtubules at the anterior flagellum region, displaying a 9 + 9 + 2 microtubular pattern, but the accessory microtubules are short and disappear quickly. The two mitochondrial derivatives differ in length and diameter. In the more posterior region, the remaining anchor-shaped mitochondrial derivative has a circular crystalline region, differing from other mecopteran species. The filiform materials are peculiar and lie beside the nucleus and in the flagellum region. Sperm ultrastructural comparison of P. kuandianensis with other families supports a close affinity of Panorpodidae with Panorpidae. In addition, the occurrence of the nine accessory microtubules in the sperm axoneme of Panorpodes indicates that the 9 + 9 + 2 axonemal pattern might be a symplesiomorphy of the Mecoptera. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT The wing of a dragonfly is thin and light, but can bear high frequent alternating stress and present excellent antifatigue properties. The surface morphology and microstructure of the wings of dragonfly Pantala flavescens were observed using SEM in this study. Based on the biological analysis method, the configuration, morphology, and structure of the vein were studied, and the antifatigue properties of the wings were investigated. The analytical results indicated that the longitudinal veins, cross veins, and membrane of dragonfly wing form a optimized network morphology and spacially truss-like structure which can restrain the formation and propagation of the fatigue cracks. The veins with multilayer structure present high strength, flexibility, and toughness, which are beneficial to bear alternating load during the flight of dragonfly. Through tensile-tensile fatigue failure tests, the results were verified and indicate that the wings of dragonfly P. flavescens have excellent antifatigue properties which are the results of the biological coupling and synergistic effect of morphological and structural factors. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: Polyethersulfone (PES) was blended with poly( D,L -lactide) (PDLLA) to prepare asymmetric membranes using the phase inversion method. The effects of the blend ratios and poly(ethylene glycol) (PEG) as additive on the membrane structure, properties, and performance were investigated. The membranes were characterized by contact angle determination, scanning electron microscopy, porosity measurement, thermogravimetric analysis, degradation tests in compost, and dynamic tests for pure water flux and bakery product wastewater treatment. PES and PEG slightly reduced the membrane contact angle. Increasing the PDLLA concentration in the blend membranes enhanced the membrane degradation in compost and also the membrane porosity. The permeate flux of the membranes was improved, but the rejection of pollution indices did not change noticeably. Porous membranes have been widely applied in the fields of dialysis, clarification, and purification. The composition of membranes prepared by blending polyethersulfone with poly( D,L -lactide) (PDLLA) affected their characteristics. Increases in the concentrations of PDLLA and the additive poly(ethylene glycol) led to more porous structures, causing higher fluxes.

Beschreibung: The separation efficiency of a pilot-scale zigzag apparatus is investigated numerically using computational fluid dynamics simulations and discrete particle modeling in a coupled manner. The effects of various process variables, like particle size and air flow velocity, and of turbulence models were analyzed. The resulting changes concerning the process performance expressed by separation function and sharpness are discussed. Moreover, the residence time distribution was found to differ for fine and coarse particle discharges. Small particles are easily carried away by the fluid and respond immediately to almost every change in flow velocity. Therefore, they are affected by vortices, which increase their residence times compared to bigger particles. Zigzag air classifiers are superior to simple sieves for the separation of particles and are used in many industrial processes. The separation efficiency of a pilot-scale zigzag apparatus is studied using combined computational fluid dynamics simulations and discrete particle modeling. The process performance is discussed with respect to the chosen modeling approach and the operating conditions.

Beschreibung: ABSTRACT Muscle fiber images play an important role in the medical diagnosis and treatment of many muscular diseases. The number of nuclei in skeletal muscle fiber images is a key bio-marker of the diagnosis of muscular dystrophy. In nuclei segmentation one primary challenge is to correctly separate the clustered nuclei. In this article, we developed an image processing pipeline to automatically detect, segment, and analyze nuclei in microscopic image of muscle fibers. The pipeline consists of image pre-processing, identification of isolated nuclei, identification and segmentation of clustered nuclei, and quantitative analysis. Nuclei are initially extracted from background by using local Otsu's threshold. Based on analysis of morphological features of the isolated nuclei, including their areas, compactness, and major axis lengths, a Bayesian network is trained and applied to identify isolated nuclei from clustered nuclei and artifacts in all the images. Then a two-step refined watershed algorithm is applied to segment clustered nuclei. After segmentation, the nuclei can be quantified for statistical analysis. Comparing the segmented results with those of manual analysis and an existing technique, we find that our proposed image processing pipeline achieves good performance with high accuracy and precision. The presented image processing pipeline can therefore help biologists increase their throughput and objectivity in analyzing large numbers of nuclei in muscle fiber images. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT Cystoisospora belli is an opportunistic protozoan that causes human cystoisosporiasis, an infection characterized by diarrhea, steatorrhea, abdominal pain, fever, and weight loss. The lack of animal models susceptible to C. belli , and the difficulty in obtaining clinical samples with fair amounts of oocysts have limited the research pertaining to the basic biology of this parasite. This study aimed to describe the ultrastructure of endogenous stages of C. belli in Monkey Rhesus Kidney Cells (MK2) and Human Ileocecal Adenocarcinoma cells (HCT-8). Zoites of C. belli exhibited typical morphological features of coccidia, which included a trilaminar pellicle, an apical complex formed by a conoid, polar rings, rhoptries, and micronemes, in addition to dense granules and the endoplasmic reticulum. No crystalloid body was observed but various lipid and amylopectin granules were usually present in the cytoplasm of zoites. We observed a tendency of the endoplasmic reticulum of the host cell to be located near the parasitophorous vacuole membrane. Merozoites were formed by endodyogeny and during replication, the apical complex of the mother cell remained intact. The formation of gametes or oocysts was not observed. The ultrastructural findings of C. belli are further evidence of its proximity to Sarcocystidae family members and corroborate their reclassification as Cystoisospora spp. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT Arge pullata Zadd is an important phytophagous pest that damages red birch Betula albo-sinensis in Hubei Province, South China. Massive ecological and economic losses have been caused by this species, which threatens the ecological security of the Shennongjia Nature Reserve. To investigate the mechanoreception, chemoreception, and oviposition processes of A. pullata , scanning electron microscopy and optical confocal microscopy were used to reveal the typology, morphology, and distribution of ovipositor and antennal sensilla. The results show that A. pullata has clavate antennae and eight types of sensilla in total, including sensilla chaetica, sensilla trichodea (types 1–3), sensilla basiconica, sensilla coeloconica (types 1 and 2), and Böhm's bristles. Sensilla trichodea type 1 distributed only on male antennae; the densities of sensilla trichodea type 2 and sensilla basiconica differed between the sexes. The binding pattern of ovipositor valvulae was discovered, and one type of sensilla chaetica, two types of sensory pits, and tooth-like cones as well as two types of microtrichia were found in the ovipositor. Based on morphological evidence and research on Hymenoptera, putative functions are suggested to increase our understanding of the mechanisms by which this species finds hosts and mates, and how oviposition takes place. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT The longicorn beetle Xylotrechus grayii (White, 1855) has been spreading rapidly in China, causing mass mortality of honeysuckle which is economically and medicinally important. In order to elucidate the mechanisms of mate and host location and to advance efficient control methods, antennal sensilla features were investigated in both sexes of X. grayii using scanning electron microscopy (SEM). The filiform antennae of both sexes consist of scape, pedicel, and nine flagellomeres (f1–9). Five types of sensilla were observed: sensilla chaetica (5 subtypes, SC1–5), sensilla basiconica (4 subtypes, SB1–4), Böhm bristles (Bm), grooved peg sensilla (Gp), and sensilla campaniformia (Ca). SC were most common on the antennae, followed by SB and Bm. No significant sexual differences in the type, amounts, and distribution of antennal sensilla were found except for the distribution of SB clusters and Ca. SB clusters and Ca occurred on f1–8 of male antennae but were absent on those segments in females, suggesting a potential function as receptors for female sex pheromones. The putative functions of other sensilla are discussed based on their characteristics in related species. This study provides an important foundation for further research on sensory mechanisms and control measures of X. grayii . Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT In mammals, the cerebral cortex microvasculature (CCM) of the neopallium plays important roles in the physiological and pathological processes of the brain. The aim of the present work is to analyze the CCM by use of the SEM-vascular corrosion cast technique, and to examine the immunocytochemical characteristics of the CCM in adult domestic ruminants (cattle, buffalo, and sheep) by using the SEM-immunogold technique. The CCM originated from the very small, finger-like terminal branches of the macrovasculature of the brain. The superficial cortical arterioles were more numerous than the deep straight arterioles which proceeded toward the white matter. The surface casts of the arterioles and capillaries of the cerebral cortex showed ring-shaped formations in the arterioles and at the origin of the capillaries. All capillaries down-stream from these ring-shaped formations were flaccid. Casts of the capillaries showed wrinkles due to the presence of endothelial folds, which is characteristic of varying blood pressure. Formations having intense anti-GIFAP immunoreactivity were frequently evident along the course of the blood capillaries in the cerebral cortex. These formations were probably astrocytes that might regulate the cerebral microcirculation based on physiological and pathological stimuli, such as neuronal activation. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT The effects of anti-angiogenic therapies in guiding tumor angioarchitecture prompted us to examine the modifications in the vascular network of the oral squamous cell carcinoma (SCC) produced by the multitargeted tyrosine kinase inhibitor sunitinib malate. Twelve Syrian hamsters had their right buccal pouches submitted to tumor induction with dimethylbenzanthracene and carbamide peroxide for 55 days. The animals were then divided into two groups of six animals each; group I was treated with sunitinib malate and group II (control) was remained untreated. After 4 weeks, the hamsters had their vascular networks casted by Mercox ® resin and analyzed by scanning electron microscopy. The qualitative study of the vascular network of the control tumor-bearing pouches showed images of intussusception and sprouting angiogenesis, flattened blood vessels, abrupt variations in their diameter, and a tortuous course. The samples treated with sunitinib exhibited a qualitative reduction of the signs of vascular proliferation. In addition, these casts presented an attenuation of the morphological features observed in the untreated tumor-bearing pouches. Quantitative analysis demonstrated that the pouches treated with sunitinib did not show a decrease ( P 〉 0.05) in the vascular diameter and intervessel distances when compared with the control group. The results of the present study suggest that sunitinib may act on the vascular network of oral SCC, normalizing the blood vessels. However, further experiments should be performed in order to determine a judicious dose of this anti-angiogenic therapy. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: In order to observe the impact of different water compositions on sludge dewaterability, assessments of floc sizes using a particle size analyzer and of sludge dewaterability based on the capillary suction time (CST) test were carried out. Synthetic raw water had small floc sizes, and synthetic domestic wastewater had both larger median floc sizes and a better correlation between sludge dewaterability and median floc sizes. The floc size distribution results showed that synthetic raw water is associated with a narrow particle size distribution. In comparison, synthetic domestic wastewater produced a wider distribution. However, the CST values were similar for both waters. Compared to synthetic wastewater, natural wastewater had the largest distribution with generally larger particle sizes. In order to observe the impact of different water compositions on sludge dewaterability, assessments of floc sizes and sludge dewaterability tests were carried out. The particle distribution results show that synthetic raw water is associated with a very narrow range of particles. In comparison, synthetic domestic wastewater produced a larger distribution. The capillary suction times were similar.

Beschreibung: ABSTRACT Due to its expansion, agriculture has become increasingly dependent on the use of pesticides. However, the indiscriminate use of insecticides has had additional effects on the environment. These products have a broad spectrum of action, and therefore the insecticide affects not only the pests but also non-target insects such as bees, which are important pollinators of agricultural crops and natural environments. Among the most used pesticides, the neonicotinoids are particularly harmful. One of the neonicotinoids of specific concern is thiamethoxam, which is used on a wide variety of crops and is toxic to bees. Thus, this study aimed to analyze the effects of this insecticide in the midgut and Malpighian tubule cells of Africanized Apis mellifera . Newly emerged workers were exposed until 8 days to a diet containing a sublethal dose of thiamethoxam equal to 1/10 of LC 50 (0.0428 ng a.i./l L of diet). The bees were dissected and the organs were processed for transmission electron microscopy. The results showed that thiamethoxam is cytotoxic to midgut and Malpighian tubules. In the midgut, the damage was more evident in bees exposed to the insecticide on the first day. On the eighth day, the cells were ultrastructurally intact suggesting a recovery of this organ. The Malpighian tubules showed pronounced alterations on the eighth day of exposure of bees to the insecticide. This study demonstrates that the continuous exposure to a sublethal dose of thiamethoxam can impair organs that are used during the metabolism of the insecticide. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: The direct-ignition technology of an entrained-flow coal-water slurry gasifier with hot-oxygen burner (HOB) is presented. Experimental tests were carried out using diesel oil and coal-water slurry in a bench-scale entrained-flow opposed multi-burner (OMB) gasifier. Using a CCD camera equipped with high-temperature endoscope, flame images inside the gasifier were recorded and subsequently processed. The results show that the HOB diesel flame is more stable than the normal two-channel burner flame typically used. Entrained-flow coal-water slurry gasifiers can start up using the HOB directly without a higher preheated wall temperature. An HOB can potentially save gasifier preheating time and operation costs and enables a wide range of future applications. Entrained-flow gasification offers one of the cleanest ways to obtain energy from coal. The direct-ignition technology of an entrained-flow coal-water slurry gasifier with a new type of hot-oxygen burner (HOB) was extensively studied to prove the feasibility of the gasifier startup with this setup. The HOB permits to effectively decrease the gasifier preheating time and the system operation costs.

Beschreibung: Different approaches were analyzed to combine the tuneable micropore structure of carbide-derived carbons with a foam-like secondary porosity. The resulting structured catalyst supports were characterized in detail and applied in the model reaction of ethene hydrogenation. Preparation methods studied were dip-coating using polytetrafluoroethylene as binder on cellular metal structures, a chemical vapor deposition coating of the metal structures with thin carbide layers and subsequent conversion to carbide-derived carbon, and the partial or full conversion of carbide foams to carbon/carbide composites. For the binder method, optimal parameters for stable slurry preparation as well as for calcination of the slurry were obtained. It could further be demonstrated that the conversion of carbide foams into carbon/carbide composites leads to an appreciation between decreasing mechanical strength and increasing specific surface area. Structured catalysts are advantageous to conventional fixed-bed systems. Carbide-derived carbons with tuneable microporous structure were combined with a foamlike catalyst structure. The three preparation methods studied resulted in highly active catalysts. Optimal conditions for the easy-to-apply dip-coating method to stabilize the slurry for successful coating were determined and evaluated.

Beschreibung: An opposed multi-burner (OMB) entrained-flow gasifier with coal water slurry feeding is developed by the East China University of Science and Technology. A 3D model is employed to numerically simulate the gas flow field, motion of char particles, and distributions of temperature and gaseous components in an OMB gasifier and in a conceptual two-stage gasifier modified from the OMB gasifier (TS-OMB gasifier). Results show that the TS-OMB gasifier produces higher concentration and productivity of the effective gases (CO+H 2 ) with a slightly higher carbon conversion than the OMB gasifier. The reasons for the differences between these two types of gasifier are discussed by means of numerical simulation. This information is valuable for guiding the design of an advanced OMB gasifier. With an increasing demand for syngas, entrained-flow gasifiers for coal conversion are installed at the fastest pace due to advantages such as low pollutant emission. Simulations of the gas component distribution, amongst other key factors, in an opposed multi-burner (OMB) gasifier and modified two-stage OMB gasifier were compared. The results are valuable for future design of an advanced OMB gasifier.

Beschreibung: ABSTRACT Autofocusing technology is indispensable for routine use of microscopes on a large scale in biological field. The autofocusing method using the angle of Hilbert space is brought forward to measure whether the image is focused or not. The angle of Hillbert space can be used to evaluate accurately the similarity degree of two images. The experiment results show that the autofocusing method can decrease the computational cost and get accuracy for real-time biological and biomedical images with noise robustness. The focus curves are smooth and possess the unimodality, the monotonicity and the symmetry. Compared with other classic and optimum focus method, the Hilbert method demonstrates its robustness to noise and can improve the focus speed. The experiments showed that the proposed method can increase the overall performance of an autofocus system and has strong applicability in various autofocusing algorithms. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT The structure of ovary in a representative of the scale insect family Matsucoccidae, Matsucoccus pini , is described at the ultrastructural level. The paired ovaries of M. pini are composed of about 50 ovarioles of telotrophic type that develop asynchronously. An individual ovariole consists of an anterior tropharium (trophic chamber) and posterior vitellarium. The tropharium encloses trophocytes (nurse cells) and early previtellogenic oocytes termed arrested oocytes. In the vitellarium from 1 to 6, linearly arranged oocytes may develop. Analysis of serial sections has shown that each ovariole contains 32 germ cells (trophocytes, arrested oocytes, and developing oocytes). In the cytoplasm of all these cells, small rod-shaped bacteria are present. In the early vitellogenic oocytes, accessory nuclei arise. As vitellogenesis progresses, these nuclei migrate toward the cortical ooplasm. The obtained results are discussed in a phylogenetic context. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: Factory. Copyright: Dmitry Lavrenyuk – Fotolia.com .

Beschreibung: ABSTRACT Many species that belong to Artiodactyls order show an interdigital sinus (IS), as it occurs in sheep, in all four extremities. These are considered to be scent glands responsible for sexual communication having strong attractiveness to mature males at the peak of the breeding season. The aim of this study was to evaluate, in IS in cyclic ewes, the microscopic and ultrastructure (scanning and transmission electron microscopy) anatomy, secretion composition, and mRNA and protein expression of estrogen receptors α and β and progesterone receptors. Glandular sebaceous structures occupy a superficial area of the pouch. The other glands present in the IS show a coiled tubular structure and tall and polyhedral secretory cells with irregular luminal surface resulting from the secretory process. Protein and mRNA gene transcription studies were performed to determine the presence of ER (α and β) and P4r in IS. At the follicular phase, IS cell populations analyzed using flow cytometry expressed higher levels of ERβ compared with ERα ( P  〈 0.05), whereas no difference was observed between them in the luteal phase. The IS amount of secretion was the highest in the follicular phase compared with luteal phase ( P  〈 0.05) or pregnancy ( P  〈 0.001).To the best of our knowledge, for the first time, the presence of ER (α and β) within the IS was demonstrated. As estrogen action is mediated by specific receptors in target cells, the presence of these receptors in IS might be needed to trigger signaling pathways involved in conspecific chemical (sexual) communication attributed to this area. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT Light microscopy has undergone a revolution with the advent of super-resolution microscopy methods that can surpass the diffraction limit. These methods have generated much enthusiasm, in particular with regards to the new possibilities they offer for biological imaging. The recent years have seen a great advancement both in terms of new technological developments and exciting biological applications. Here, we review some of the important milestones in the field and highlight some recent biological applications. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: ABSTRACT This study focused on test the null hypothesis that there is no difference between the degree of conversion and biocompatibility of different resin reinforced glass ionomer cements (RRGICs). Forty-eight male Wistar rats were used, distributed into four groups ( n  = 12), as follows: Group C (Control, polyethylene), Group FOB (Fuji Ortho Band), Group UBL (Ultra band Lok), and Group MCG (Multicure Glass), in subcutaneous tissue. The events of edema, necrosis, granulation tissue, multinuclear giant cells, young fibroblasts, and collagen formation were analyzed at 7, 15, and 30 days. The degree of conversion was evaluated by the Fourier method. Biocompatibility and degree of conversion were assessed using the Kruskal–Wallis and Dunn tests, and ANOVA and Tukey's test, respectively ( P  〈 0.05). It was observed that, there was significant difference between Groups FOB and UBL for the presence of young fibroblasts at 15 days ( P  = 0.034) and between the Control and MCG Groups for the presence of multinucleated giant cells at 30 days ( P  = 0.009). Monomer conversion increased progressively until day 30, with significant difference between Group FOB and Groups UBL and MCG ( P  = 0.013) at 15 days. The null hypothesis was partially accepted, Fuji Ortho Band showed a less monomer conversion and a smaller number of young fibroblasts in the time of 15 days. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: Steel pipe line. Copyright: supakitmod – Fotolia.com.

Beschreibung: Light olefin and paraffin are commonly separated by energy-intensive cryogenic distillation. Membrane/distillation hybrid systems constitute an economical alternative separation process. Different configurations of this hybrid system are studied for olefin-paraffin separation with emphasis on C 3 separation. An approach based on the McCabe-Thiele method is applied to analyze different process configurations. A facilitated transport membrane is considered as membrane type. Both new column design and augmentation of an existing distillation column by a membrane module are considered. Numerical examples are considered for the separation of propane from propylene through different hybridization shapes with facilitated transport membranes. The energy requirement can be halved using hybrid systems. Membrane/distillation hybrid systems represent an economical alternative separation process compared to the commonly applied energy-intensive cryogenic distillation for separation of light olefin and paraffin. Different process configurations of such a hybrid system are evaluated. Under optimum conditions the energy requirement could be halved.

Beschreibung: Virtual auditing can be a ­cost-effective audit program tool

Beschreibung: Economic measures still lead as most frequently used performance measurements

Beschreibung: Efforts to identify environmental conditions, limit liability in commercial property transfers, continue to evolve

Beschreibung: Products in commerce in California are targeted, but the program has national and international implications

Beschreibung: Assessment of current practices and policieswith recommendationsfor future improvements

Beschreibung: ABSTRACT Several treatments have been developed aiming the prevention of bone loss. There are discussions about the best prophylactic and therapeutic procedures for osteoporosis. This study evaluated the effects of physical exercise associated with risedronate as a prophylactic and therapeutic procedure in osteopenic bones of rats submitted to ovariectomy. We used 48 Wistar rats divided into: ovariectomized or subjected to sham surgery. Ovariectomized rats were divided into the following sub-groups: OVX, 12 weeks sedentary; OVX-EX, treadmill training for 12 weeks; OVX-RA, 12 weeks with risedronate administration; and OVX-EX-RA, 12 weeks with risedronate administration and treadmill training. Rats subjected to sham surgery were divided into the following sub-groups: SH, 12 weeks sedentary; SH-EX, treadmill training for 12 weeks; SH-RA, 12 weeks with risedronate administration; and SH-EX-RA, 12 weeks with risedronate administration and training on the treadmill. The effectiveness of the treatment was evaluated in tibias using biomechanical, radiological, histomorphometric, and immunohistochemical analyses. Data were analyzed by statistical tests, with significance level of P  〈 0.05. Results of mechanical tests showed that the SH-RA group had lower values compared with OVX-RA group; densitometry showed no significant differences; according to histomorphometric methods, OVX group presented lower results than the SH-EX, OVX-RA, SH-EX-RA, and OVX-EX-RA groups, and SH-EX-RA and OVX-EX-RA groups showed values higher than SH-RA, SH, and OVX-EX groups. The SH-EX-RA and OVX-EX-RA groups had decreased immunostaining for tartrate-resistant acid phosphatase and receptor activator of nuclear factor kappa-B ligand and increased osteoprotegerin immunostaining. In this experimental model, it was concluded that the physical training associated with use of risedronate exerted positive effects on biomechanical and microstructural properties in bones of ovariectomized rats. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: To reduce environmental impact of cement production, granulated blast furnace slag (GBFS) can be used as a cement clinker substitution. Its reactivity of can be increased by adequate fine grinding. The impact of different conventional laboratory-scaled mills (ball mill, vertical mill, and roller press) on the material properties was researched. Granulometrical, structural, and calorimetrical investigations were done. It could be demonstrated that at the same fineness the grinding unit does not significantly influence the cement performance like hydration heat release and compressive strength. On the other hand, particle properties like particle size distribution, particle shape, and thus workability characteristics of composite cements have been changed. The replacement of ordinary produced cement by ground granulated blast furnace slag (GGBFS) in the cement production reduces negative impacts on the environment. By adequate fine grinding the reactivity of GGBFS as a cement linker substitution could be enhanced. The influence of grinding devices on the reactivity of GGBFS is investigated and evaluated.

Beschreibung: The impact of polydispersity index (PDI) values and doses of two sodium polyacrylates on grinding limits and particle size distributions of highly concentrated limestone suspensions was studied. The results indicated that viscosity and agglomerate particle size, and thus the apparent grinding limit, depended on the sodium polyacrylate dose as well as PDI value of sodium polyacrylate. The higher the sodium polyacrylate dose, the lower the viscosity and the smaller the apparent grinding limit were. The smallest primary particle size, the smallest apparent grinding limit, the narrowest agglomerate particle size distribution, and the lowest viscosity curve were obtained with sodium polyacrylate having a low PDI. Ultrafine grinding of limestone in stirred media mills is an attractive method for nano-CaCO 3 production. Effects of polydispersity index and doses of two sodium polyacrylates on the grinding limits of limestone suspensions were studied. Sodium polyacrylate with a low polydispersity index turned out to be an effective grinding aid for limestone.

Beschreibung: A method was sought that allows for coordinating the particle grinding time and the particle size in a closed milling circuit. This can be achieved by placing the input of the return flow from an end classifier at an intermediate position of the tube mill length. A simple model to estimate the efficiency of the approach is proposed. It is shown that such an optimal position exists and depends on the classifier efficiency. One of the key problems in improving the efficiency of grinding is how to match the particle size and the necessary grinding time. A model for optimizing the position of the circulating load input in a closed milling circuit with a tube mill is proposed. It is shown that such an optimum does exist and can yield a considerable gain in the circuit capacity.

Beschreibung: Phenomena related to sieving of non-spherical particles are investigated numerically in two batch apparatuses and on a horizontally aligned continuous sieve by particle-based simulation approaches in the framework of the discrete element method. The feed material is approximated by complex-shaped particles composed of clustered spheres. Comparisons are made with regard to the passage through the screen as well as the segregation and transportation on the screen. Results for passage are compared to data from literature, where simulations with spherical particles were performed of a laboratory-scale sieve operated with non-spherical quarry rock particles. Additionally, variations in screen inclination are investigated. Experimental results are matched by the simulations. A distinctive influence of particle shape on flow rates and residence times is identified. Despite many modeling advances, phenomenological models still lack the ability to represent dynamic processes within the unit operation sieving. Here, discrete element method simulations of complex-shaped particles on two batch apparatuses and a continuously operated sieve are performed. Phenomena related to sieving of non-spherical particles are investigated numerically.

Beschreibung: The process and end-use behavior of ground material not only depends on the particle size or specific surface but is also influenced by the particle shape. Particle shaping can be done in a stirred media mill if the stress intensity is not enough to break the particle, so mainly abrasion and chipping are carried out. Low-stress intensity milling is presented in a dry stirred media mill to reveal the particle base rounding and surface roughness reduction. The main parameters of the product-related stress model are connected to the descriptive parameters of particle shaping. Batch grinding of limestone particles with narrow size distribution was carried out with different milling parameters. The product-related stress model can be used for the description of particle shaping. The rounded shape and smooth surface of particles is necessary for many processes. A stirred media mill was used in dry mode to produce rounded or smooth surface particles in a size range of a few hundred microns without significant size reduction. An evaluation method was created to show the effect of the milling parameters on the particle shaping in relation to the product-related stress model.

Beschreibung: The influence of several process parameters like milling time, ball-to-beaker volume ratio, diameter of milling balls, and rotation frequency on the Knoevenagel condensation of vanillin and barbituric acid in planetary ball mills was investigated. These parameters determine the amount of energy provided for the reaction. Additionally, numerical simulations were carried out to describe the stress conditions in detail and to compute the drive power and energy transfer which cannot be measured directly. The mill and experimental parameters were modeled by the discrete element method with adequate coefficients of friction and restitution required to describe the powder behavior in the system. The coefficients were determined by correlation of experiments and simulations. Mechanochemical synthesis may offer green solutions to organic synthesis. Using the Knoevenagel reaction under solvent-free conditions in a planetary ball mill, the results are correlated with discrete element method simulations to prove the dependency of the reaction yield on stress conditions. Smaller balls were more time and energy efficient due to higher power values achieved by high stress frequencies.

Beschreibung: The aim of this work is to clarify the complex interactions and various influencing parameters regarding the material behavior of deep-frozen bulk solids. Additionally, a better evaluation of the material behavior in practical applications needs to be ensured. As material samples, hard coal, iron ore, and sand were selected, and cube-shaped samples saturated with water were deep-frozen for defined periods of time. Subsequently, the influences of the residence time in the freezer and of the particle size on the material behavior were analyzed by carrying out uniaxial compression tests. An economically and technically efficient method is needed to overcome the problems associated with frozen coal. Hard coal, iron ore, and sand samples saturated with water were deep-frozen for defined periods of time. Uniaxial compression tests were carried out to analyze the influence of the particle size and the residence time in the freezer on the material behavior.

Beschreibung: A general overview for the process development and manufacturing of engineered drug particles by size reduction techniques is provided. Drug compound and drug product characteristics are reviewed, which may need an engineered drug particle size. Drug particle attributes are introduced which are affected by size reduction techniques and potentially require additional downstream processing effort. The development of drug particle size specifications is described, including adequate size control. A brief overview is given on dry- and wet-milling technologies currently applied in drug development and manufacturing, including selected application examples. Finally, the processing of highly active drug compounds is introduced with respect to equipment design, worker protection, cleaning and waste management to minimize worker exposure and environmental impact. A brief overview is given on drug compound and drug product characteristics impacted by drug particle size. Size reduction techniques applied after chemical synthesis and isolation processing are introduced for the engineering of drug particle size. The repercussions for the processing of highly active drug compounds are overviewed with regard to worker exposure and environmental impact.

Beschreibung: The production of nanosuspensions via stirred-media milling has proved to be an effective method to overcome bioavailability challenges of poorly water-soluble active pharmaceutical ingredients (APIs). The fine-grinding of the APIs cinnarizine and fenofibrate was investigated. Important process parameters were varied and the influence on product quality was studied. Different challenges were identified prior to and during milling: Foaming inside the milling equipment and agglomeration of fenofibrate occurred, and a long-term grinding experiment for cinnarizine revealed an increase in particle size, caused by ripening of the drug crystals during milling. Thus, the stability against ripening during the process is a newly identified challenge for the fine-grinding of APIs. The influence of process parameters on product quality for the milling of the active pharmaceutical ingredients fenofibrate and cinnarizine was investigated. Besides the well-known challenge regarding stabilization of the newly formed (nano)particles, a further challenge occurred: the ripening of the cinnarizine crystals during or shortly after the milling process.

Beschreibung: The interest in finer, dry products has led to the development of more efficient jet milling processes. The first part of the paper describes the thermodynamic basic principles for generation and application of steam, and compressed gases. Practical experience has shown that in the aspired fineness range stabilization during grinding provides an enormous potential for improvement. Some selected examples demonstrate that the energy requirement can be reduced by a factor of more than two by suitable choice of stabilizers. Application of single-stage, uncooled low-pressure compressors for jet milling offers an economical alternative to double-stage, cooled compressors for fine grinding. Stabilization during grinding provides an enormous potential for improvement. Selected examples demonstrate that the energy requirement can be reduced by a factor of 〉 2 with suitable stabilizers.

Beschreibung: Wet grinding processes, especially in terms of nanoparticle production, are extremely energy intensive, and for hard and abrasive product materials, high grinding media wear is produced. In order to minimize energy consumption, the choice of the process parameters is crucial. The decision on the process parameters often depends on experience or a certain number of laboratory- or pilot-scale experiments. Here, an enhanced stress energy model is used, which enables the prediction of optimum process parameters for inorganic materials in wet stirred media milling based on results for a different grinding material. The use of this model to select the process parameters is also valid with regard to grinding media wear: The grinding media wear reaches minimum values if the optimum parameters pertaining to the minimum specific energy are chosen based on this enhanced stress energy model, especially if soft products are ground. An enhanced stress energy model is used for the prediction of optimum process parameters for inorganic materials in wet stirred media milling based on results for a different grinding material. Optimization of the process parameters leads to minimum wear values for a certain product fineness, especially for materials that are softer than the grinding media material.

Beschreibung: Wheat bran is a vegetal fibrous material rich in different chemicals (e.g. arabinoxylan) that can be used as food ingredient. To increase the extractability of these compounds, production of small fiber particles and therefore milling for long periods of time have been proposed. Different laboratory- and pilot-scale technologies for fine and ultrafine grinding of wheat bran were evaluated in this publication. Various milling tools were applied both under wet and dry conditions. Generally better results were obtained when grinding the wheat bran under dry condition. Optimum results were achieved by a combination of ball milling followed by treatment of the powder with a jet air mill. Electron microscopic evaluation confirmed the sub-micrometer size of most particles and the presence of agglomerates. Wheat bran fibers are important in the food industry. Smaller fiber particle sizes could increase the extractability of its components. Therefore, different milling conditions were tested and optimal results were obtained when dry wheat bran was milled with a ball mill followed by a jet mill. Generally, finer particle size distributions could be achieved when dry milling conditions were applied.

Beschreibung: The study presents an old icon painted in egg tempera on lime wood, with a poor conservation condition and clogged dirt deposits. The icon is attributed to an anonymous painter of XIXth century and to the neo-classical style of painting. The painting layer was done with only a hand full of pigments, earth colors that were often used in painting the icons from XVIIth to XIXth century in Eastern Europe, that have Byzantine influences. Taking into consideration the nature and the structure of the materials from the upper layers of the painting, affected by deposits of dirt over time, a series of cleaning recipes were studied, using the so called cleaning tests with compatible mixtures of different juices and infusion from indigenes plants, that were freshly done and odorless. A low alkaline 95% ethyl alcohol solution, combined with a few drops of ammoniac 25%, was used as a reference system, due to its compatibility with the greasy deposits found on the polychrome layer and on the wood. The cleaning capacity of the new systems used, in comparison with the standard solution, was analyzed through modern analytical methods of evaluating the degree of cleaning, more exactly by means of visible and UV reflectography, CIE L*a*b* colorimetry by reflection assisted by SEM-EDX and IR spectroscopy. Microsc. Res. Tech., 2014 . © 2014 Wiley Periodicals, Inc.

Beschreibung: A new mathematical model of the collision probability between bubbles and non-spherical particles is proposed. In this model it is assumed that the characteristic size of the particle is much smaller than the bubble radius; the particle density is close to the density of the flotation medium and the particle moves along a streamline flowing around the floating bubble (so-called inertialess flotation). So, the stochastic orientation of the particle with respect to the bubble surface was considered. On the basis of this model, the analytical expressions of the collision probability for rod-like and disk-like particles in the Stokes and Levich hydrodynamic regimes were obtained. The obtained results were compared with previous theories and experimental data. For a particle suspended in an aqueous medium to be captured, the rising bubble must first collide with this particle. A new mathematical model of the collision probability between bubbles and non-spherical particles is proposed, considering the stochastic orientation of the particles with respect to the bubbles surface. The results are compared with previous theories and experimental data.

Beschreibung: Porocritical extraction was applied to the separation of 1-butanol and acetone from aqueous solutions modeling a typical acetone-butanol-ethanol (ABE) fermentation broth. The efficiency of two lab-scale hollow-fiber membrane contactors of different was studied under various flow rates, solvent-to-feed ratios, and pressure conditions. Global and individual, i.e., tube side, membrane, and shell side mass transfer coefficients were determined. The main contribution to mass transfer resistance was found in the shell side in all cases, and experimentally determined shell side mass transfer coefficients were compared to values predicted by existing correlations. The porocritical extraction process combines the porosity of hollow fibers with the properties of supercritical fluids to create a nondispersive contact between solvent and aqueous feed and is particularly suited for the recovery of organic compounds from aqueous solutions. 1-Butanol and acetone were extracted from a model aqueous solution containing concentrations typically found in fermentation broths.

Beschreibung: The chiral resolution of two racemic cyclopropanecarboxylic acids with the resolving agents ( S )-2-( N -benzylamino)butan-1-ol and ( R )-1-phenylethanamine was investigated. The resolutions were based on diastereomer salt crystallization in supercritical carbon dioxide. Unreacted compounds were removed by an extraction step. Experiments were performed in a continuously stirred tank reactor and good enantioselectivities were obtained in a single step. Pressure, temperature, and density were found to strongly affect both the optical purity and the selectivity of the resolutions. The crystal structures of the formed diastereomer salts were also studied via X-ray diffraction. The modified Pope-Peachy method, a resolution technique, is applied to realize the organic solvent-free chiral resolution of two racemic acids using supercritical CO 2 as reaction medium. A fast reaction system is presented and in vacuo and in situ methods to achieve enantiomer separation of the racemic acids are compared. Good enantioselectivities were obtained in a single step.

Beschreibung: In situ synthesis of silica gels via a one-step sol-gel process at ambient pressure or in supercritical CO 2 was investigated. The influence of compressed gas, ultrasound irradiation, and quaternary ammonium salt (choline chloride) on the gelation time was determined. The obtained samples were characterized by N 2 adsorption/desorption measurements, scanning electron microscopy in combination with energy dispersive X-ray spectroscopy (SEM/EDX), and Fourier transform infrared-attenuated total reflection spectroscopy (FTIR-ATR). The retention capacity of the corresponding silica aerogels for Rhodamine B was evaluated as a model for organic water pollutants. The obtained results proved that scCO 2 has a beneficial effect, leading to a reduction of the gelation time. The obtained aerogels exhibit a higher surface area and larger pore diameter as well as a well-defined cylindrical pore structure. The potential applications of silica aerogels in adsorption and catalysis are closely related to their nanostructure, pore size, and pore shape. The proposed one-step synthesis of silica aerogels employing supercritical CO 2 and ultrasound as well as choline chloride as quaternary ammonium salt is a proper way to reduce the gelation time and to design porous materials with tailor-made properties.

Beschreibung: A design strategy allowing the development of an inexpensive microdevice with a cylindrical section able to work at high pressures is established. The setup combines good optical access, high-pressure resistance, homogeneous operation conditions, fast process control and detection, and the ability to generate a stable two-phase flow. The experiments are conducted in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and supercritical carbon dioxide flow under isothermal conditions. The two-phase flow system is observed with a high-speed camera. An image processing procedure is performed on the films in order to determine the global two-phase flow geometrical characterizations. Coupling high-pressure processes with microtechnology provides decisive advantages for different fields of applications. A low-cost, transparent, and easily optically accessible high-pressure microdevice is developed. The applied strategies enable fast process control and detection and permit the generation of homogeneous operation conditions and a stable two-phase flow under high-pressure performance.

Beschreibung: Wet flue gas desulfurization systems are commonly applied to remove sulfur dioxide by contacting it with limestone in an aqueous phase. The effects of pH, stirring speed, solid-to-liquid ratio, acid concentration, and temperature on the dissolution rate of limestone in adipic acid were investigated. The reaction dissolution kinetics was determined by fitting the experimental data into the shrinking core model. The sorbent was characterized at different dissolution periods. An increase in the specific surface area of the sorbent was attributed to formation of portlandite. The experimental data were found to fit the shrinking core model with chemical reaction control. A semi-empirical model was developed from the experimental data to describe the dissolution kinetics. The SO 2 removal efficiency of wet flue gas desulfurization systems using limestone as sorbent can be improved by addition of various organic acids. The dissolution kinetics of limestone in adipic acid was investigated. The effects of decisive process variables were determined and a semi-empirical model was developed for the process. The dissolution of limestone follows a shrinking core model with chemical reaction control.

Beschreibung: Energy production from phytomass residues such as harvest leftovers is generally accepted as a sustainable way. Excellent results may be reviewed in papers based on laboratory observations. However, trials performed on a commercial scale show that without proper disintegration long retention times, huge fermenters, or various chemicals are required. The results obtained in a commercial scale suggest that intensive disintegration makes subsequent processes less manageable. Two conventional methods of nutrient management and the recently proposed method, which takes into account the availability of nutrients, have been robustly tested. The data from all three methods and the technological and cost assessment that followed demonstrated that the application of the newly proposed method opens up the potential for further optimization, which may lead up to significant reductions in energy price. Energy production from phytomass residues is generally accepted as a promising and sustainable way. Two conventional methods of nutrient management and a recently proposed method, which considers the availability of nutrients, were compared. As a result, the application of the newly proposed method provides great potential for further optimization, which may lead to significant reductions in energy price.