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1
Lakevičs, Vitālijs, Valentīna Stepanova, and Augusts Ruplis. "Thixotropic Properties of Latvian Clays." Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 1 (August 5, 2015): 318. http://dx.doi.org/10.17770/etr2011vol1.903.
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This research studies Latvia originated Devon (Tūja, Skaņkalne), quaternary (Ceplīši), Jurassic, (Strēļi) and Triassic (Vadakste) deposit clays as well as Lithuania originated Triassic (Akmene) deposit clays. Thixotropic properties of clay were researched by measuring relative viscosity of clay in water suspensions. Relative viscosity is measured with a hopper method. It was detected that, when concentration of suspension is increased, clay suspension’s viscosity also increases. It happens until it reaches a certain boarder point when viscosity increases significantly – a dramatic rise is shown on the curve. It means that clay particles make a lace-like, easily broken structure. Impact of chemical reagents on clay suspensions’ thixotropic properties is researched. Experimental results obtained on the new materials with thixotropic properties will allow precise definition of production technologies and usage of a new approach in development of motivation products. Likewise, the results will make an important investment in establishing a thixotropic material description methodology.
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Seto, Kazuto. "Special Issue on Advanced Vehicle Dynamics and, Control." Journal of Robotics and Mechatronics 7, no. 4 (August 20, 1995): 273. http://dx.doi.org/10.20965/jrm.1995.p0273.
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Various attempts have been made from olden days on vehicles for better riding comfort and for improved maneuverability. Past vehicles have achieved vibration isolation performance, which relaxes impact from road surfaces, by means of link mechanisms and passive suspensions consisting of springs and dampers, as well as basic motion performance such as running, turning, and stopping. However, as far as passenger cars are concerned, a passive suspension has its own limitation, and the contradiction that if riding comfort is to be improved at low speeds, the maneuverability during high-speed operations becomes bad has not been solved. Demand of users has become stronger and stronger for vehicles which satisfy riding comfort and maneuverability at the same time. Moreover, as far as trains are concerned, the past technology has increased the vibration of trains as they are operated at higher speeds; thus a drop in riding comfort has been a cause for preventing high-speed operations. Nevertheless, in line with progress in mechatronic technology, active suspensions have been adopted aggressively in automobiles and trains in recent years, and attempts have been started for improving both riding comfort and maneuverability to satisfy demand of users. Some passenger cars have already appeared which are equipped with an active suspension. A similar trend is found in the case of trains; by the introduction of active suspensions, operations of trains on conventional lines at higher speeds are being started. Under these circumstances, this special issue has been created. Although high performance in vehicles may be achieved by means of active suspensions, the problem of increased energy consumption has become a serious issue, which has been brought to the fore with the bursting of the bubble. This problem seems to be solved by saying how effectively semi-active suspensions may be realized. In this special issue, new trends have been taken up, such as vehicle dynamics, design theory on active suspension systems, reduction of engine vibration by optimum design of hydraulic engine mounts, design of control systems for neural networks of semi-active suspension systems, control of variable structures of suspension systems, predictive control, magnetic levitation suspension, etc. It is hoped that these articles will be useful in future research.
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Luccia, N. De, and H. L. T. Marino. "Case study: Fitting of electronic elbow on an elbow disarticulated patient by means of a new surgical technique." Prosthetics and Orthotics International 24, no. 3 (December 2000): 247–51. http://dx.doi.org/10.1080/03093640008726556.
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Rehabilitation of transhumeral amputees represents a challenge. One of the difficulties to overcome is prosthetic suspension. In the case of elbow disarticulation the presence of humeral condyles permits better suspension, but there is no room for elbow joints, particularly electronic ones, and the only available mechanisms are provided by external hinges. The purpose of this report is to present a case of a primarily elbow disarticulated patient, with indication for surgical revision due to bad skin coverage, neuroma and the wish to improve prosthetic fitting. The surgical plan outlined was to produce a shortening of the humerus, by means of an osteotomy just above the humeral condyles, preserving them for prosthetic suspension. This bone reduction was carried out with complementary shaping of bone segments with an indentation to enhance fixation. The operation was completed with neuroma resection, myodesis and removal of the skin grafted area. Preservation of the humeral condyles actually produced effective suspension. For final fitting a Utah Arm II was used, with wrist rotator, and interchangeable hand and Greifer for terminal devices. Good initial results and at nine months followup suggest this procedure should be considered in other elective situations.
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Blum, Krieg, Killinger, Gadow, Luth, and Trenkle. "High Velocity Suspension Flame Spraying (HVSFS) of Metal Suspensions." Materials 13, no. 3 (January 30, 2020): 621. http://dx.doi.org/10.3390/ma13030621.
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Thermal spraying of metal materials is one of the key applications of this technology in industry for over a hundred years. The variety of metal-based feedstocks (powders and wires) used for thermal spray is incredibly large and utilization covers abrasion and corrosion protection, as well as tribological and electrical applications. Spraying metals using suspension- or precursor-based thermal spray methods is a relatively new and unusual approach. This publication deals with three metal types, a NiCr 80/20, copper (Cu), and silver (Ag), sprayed as fine-grained powders dispersed in aqueous solvent. Suspensions were sprayed by means of high-velocity suspension spraying (HVSFS) employing a modified TopGun system. The aim was to prepare thin and dense metal coatings (10–70 µm) and to evaluate the process limits regarding the oxygen content of the coatings. In case of Cu and Ag, possible applications demand high purity with low oxidation of the coating to achieve for instance a high electrical conductivity or catalytic activity. For NiCr however, it was found that coatings with a fine dispersion of oxides can be usable for applications where a tunable resistivity is in demand. The paper describes the suspension preparation and presents results of spray experiments performed on metal substrates. Results are evaluated with respect to the phase composition and the achieved coating morphology. It turns out that the oxidation content and spray efficiency is strongly controlled by the oxygen fuel ratio and spray distance.
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Marcovich, N. E., M. L. Auad, N. E. Bellesi, S. R. Nutt, and M. I. Aranguren. "Cellulose micro/nanocrystals reinforced polyurethane." Journal of Materials Research 21, no. 4 (April 1, 2006): 870–81. http://dx.doi.org/10.1557/jmr.2006.0105.
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Nano- and micron-sized cellulose crystals were prepared and utilized as reinforcements for polyurethane composites. The cellulose crystals obtained from microcrystalline cellulose (MCC) were incorporated into a polar organic solvent, dimethylformamide (DMF), and ultrasonicated to obtain a stable suspension. The suspension was an effective means for incorporating the cellulose crystals into the polyol-isocyanate mixture, utilized to produce polyurethane composite films. The use of DMF presents an interesting alternative for the use of cellulose crystals as reinforcement of a broad new range of polymers. Moreover, the rheology of the uncured liquid suspensions was investigated, and analysis of the results indicated the formation of a filler structure pervading the liquid suspension. Besides, films were prepared by casting and thermal curing of the stable suspensions. Thermomechanical and mechanical testing of the films were carried out to analyze the performance of the composites. The results indicated that a strong filler-matrix interaction was developed during curing as a result of a chemical reaction occurring between the crystals and the isocyanate component.
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Yang, Lin, Ruochen Wang, Xiangpeng Meng, Zeyu Sun, Wei Liu, and Yong Wang. "Performance analysis of a new hydropneumatic inerter-based suspension system with semi-active control effect." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, no. 7 (January 6, 2020): 1883–96. http://dx.doi.org/10.1177/0954407019894189.
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This paper develops a hydropneumatic inerter-based suspension system theoretical model to analyze its performance, based on the mechanical network theory of inerter and semi-active control. Comparison of the stiffness and damping characteristics among a passive hydropneumatic suspension system, semi-active hydropneumatic suspension system based on skyhook control, and hydropneumatic inerter-based suspension system is conducted. Moreover, the relationship between the internal coefficient of the inerter and the damping coefficient of the hydropneumatic suspension is investigated. The simulation results of the flow–volume curves of the hydropneumatic inerter-based suspension system are close to those of the semi-active hydropneumatic suspension system based on skyhook control. Furthermore, the performance of a quarter vehicle model with the hydropneumatic inerter-based suspension system is analyzed and compared to that with the semi-active hydropneumatic suspension system based on skyhook control. The simulation results show that the performance of the hydropneumatic inerter-based suspension system is as good as that of the semi-active hydropneumatic suspension system based on skyhook control, which means that the hydropneumatic inerter-based suspension system can achieve similar performance for semi-active control suspension. Finally, a prototype is developed, and a comparative bench test is carried out to verify the accuracy of the simulations. In addition, the hydropneumatic inerter-based suspension system can achieve semi-active control performance without additional hardware or energy loss.
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Shi, Xiao Hui, Hong Li Gao, and Ming Heng Xu. "Optimization Design of Automobile Suspension Springs Based on BP." Applied Mechanics and Materials 42 (November 2010): 82–85. http://dx.doi.org/10.4028/www.scientific.net/amm.42.82.
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In order to optimize the arithmetic of the automobile suspension springs, the optimization algorithm of spring stress model based on BP neural networks was proposed. The various models of suspension spring were aggregated and analyzed, the parallel genetic algorithm for the suspension springs was proposed in this paper as well. And the spring models can be optimized fast and efficiently by the algorithm. Aiming at different models, the maximum stress point and the distribution law are given by means of experimental verifications. A new stress analysis method and a new estimate rule for the design of automotive suspension springs are provided by this method.
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Qiu, Jing, Rui Li Shen, and Huai Guang Li. "Mechanics Characteristics Study for Cable-Stayed-Suspension Bridges." Advanced Materials Research 243-249 (May 2011): 1817–25. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.1817.
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As a composite structure, the cable-stayed-suspension bridge is characterized by relatively new structure, great overall stiffness and long-span capacity, which has been proposed for the design of some extra long-span bridges. In order to research further into the mechanics characteristics of this type of structural system, the proposed preliminary design of a cable-stayed-suspension bridge with a main span of 1800m is analyzed by means of finite element simulation method. The advantages on overall stiffness in the cable-stayed-suspension bridge are summarized in comparison with the three-span suspension bridge and the single-span suspension bridge. Then, the reasons for the fatigue of the longest suspension cables in the cable-stayed-suspension bridge are also discussed in this paper.
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Zheng, Hong Yu, Huai Yan Jiang, and Zhi Tao Lu. "Natural Vibration Characteristics of Long-Span Suspension Bridge with CFRP Cables." Advanced Materials Research 168-170 (December 2010): 1708–11. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.1708.
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A non-corrosion, high strength, light weight material – carbon fiber reinforced polymer (CFRP) is introduced to replace steel as cable system in long-span suspension bridge for improving loading efficiency, reducing maintenance cost, enlarging the span of suspension bridge. The natural vibration characteristics of such new suspension bridge with CFRP cables are investigated by means of finite element in this paper. Two 2000m-span suspension bridges with steel cables and CFRP cables respectively are designed, analyzed, verified and compared. The analysis results provide a picture of the changes in natural vibration characteristics and the wind stability and earthquake-resistant behavior are briefly discussed if CFRP cables were applied.
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Cheng, Fei, Jing Yi Zhao, Rui Guo, and Bing Yu Sun. "The Noise Fault Analysis and Exclusion in Self-Propelled Transporter Hydraulic System." Applied Mechanics and Materials 347-350 (August 2013): 138–42. http://dx.doi.org/10.4028/www.scientific.net/amm.347-350.138.
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Noise is one of the common faults in hydraulic system. The correct analysis and deal with the noise will make for the normal operation and optimization of the system. In view of the noise of a new self-propelled transporter suspension hydraulic system produced in the debugging process of the heavy load lifting when suspension falling, by means of mechanism analysis, modeling and simulation analysis of the suspension hydraulic system, finding out the noise comes from the hydraulic component of system with SV type pilot check valve; The noise fault is caused by the improper circuit design of hydraulic system, the feasibility of the using the SL type pilot check valve to eliminate suspension hydraulic system noise proved by the simulation analysis, in the field test of the improved suspension hydraulic system, the suspension falling gentle and noise elimination, which shows that the analysis and simulation model is correct; Through the comparison and analysis on the SV type and SL type kinds of pilot check valve on the reasonable application in the hydraulic circuit isolation, that provides a theoretical basis for the correct selection two kinds of pilot check valve.
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Shen, Yujie, Long Chen, Yanling Liu, and Xiaoliang Zhang. "Modeling and Optimization of Vehicle Suspension Employing a Nonlinear Fluid Inerter." Shock and Vibration 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/2623017.
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An ideal inerter has been applied to various vibration engineering fields because of its superior vibration isolation performance. This paper proposes a new type of fluid inerter and analyzes the nonlinearities including friction and nonlinear damping force caused by the viscosity of fluid. The nonlinear model of fluid inerter is demonstrated by the experiments analysis. Furthermore, the full-car dynamic model involving the nonlinear fluid inerter is established. It has been detected that the performance of the vehicle suspension may be influenced by the nonlinearities of inerter. So, parameters of the suspension system including the spring stiffness and the damping coefficient are optimized by means of QGA (quantum genetic algorithm), which combines the genetic algorithm and quantum computing. Results indicate that, compared with the original nonlinear suspension system, the RMS (root-mean-square) of vertical body acceleration of optimized suspension has decreased by 9.0%, the RMS of pitch angular acceleration has decreased by 19.9%, and the RMS of roll angular acceleration has decreased by 9.6%.
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Mazzola, Laura, and Stefano Bruni. "Effect of Suspension Parameter Uncertainty on the Dynamic Behaviour of Railway Vehicles." Applied Mechanics and Materials 104 (September 2011): 177–85. http://dx.doi.org/10.4028/www.scientific.net/amm.104.177.
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The paper describes a study carried out by Dipartimento di Meccanica Politecnico di Milano, aimed at investigating how uncertainty in railway vehicle suspension components can be treated in the framework of vehicle design and performance assessment in respect to vehicle dynamics. In railway vehicle suspensions, sources of parameter uncertainty may arise from inaccuracy in the modelling of a vehicle component or from a scatter in the behaviour of nominally identical components, on account of the variability implied by the component manufacturing process. The approach proposed in this paper, completely new to the railway field, is to use statistical methods having different complexity (and entailing a proportional computational effort), to analyse the propagation of uncertainty from the parameters input in the vehicle mathematical model to the results of running dynamics, in terms of the assessment quantities used for verification and evaluation of train performances. The problem is treated by numerical means, being the dependency of simulation outputs from the input parameters typically non-linear, and not defined in an analytical form.
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Smith, L. J., and S. Benchimol. "Introduction of new genetic material into human myeloid leukemic blast stem cells by retroviral infection." Molecular and Cellular Biology 8, no. 2 (February 1988): 974–77. http://dx.doi.org/10.1128/mcb.8.2.974.
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An amphotropic retroviral vector containing the bacterial neomycin phosphotransferase gene (neo) was used to infect blast cells from patients with acute myeloblastic leukemia. The infected cells acquired a G418-resistant phenotype that was stable as measured in a clonogenic assay and in long-term suspension culture. Thus, gene transfer into stem cells was accomplished by this procedure. This approach for manipulating gene expression in blast stem cells provides a means to assess the roles of a variety of genes in self-renewal, differentiation, and leukemogenesis.
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Smith, L. J., and S. Benchimol. "Introduction of new genetic material into human myeloid leukemic blast stem cells by retroviral infection." Molecular and Cellular Biology 8, no. 2 (February 1988): 974–77. http://dx.doi.org/10.1128/mcb.8.2.974-977.1988.
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An amphotropic retroviral vector containing the bacterial neomycin phosphotransferase gene (neo) was used to infect blast cells from patients with acute myeloblastic leukemia. The infected cells acquired a G418-resistant phenotype that was stable as measured in a clonogenic assay and in long-term suspension culture. Thus, gene transfer into stem cells was accomplished by this procedure. This approach for manipulating gene expression in blast stem cells provides a means to assess the roles of a variety of genes in self-renewal, differentiation, and leukemogenesis.
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PRICE, COLE, and MARTIN A. HUBBE. "Spraying starch on the Fourdrinier— An option between wet end starch and the size press." January 2021 20, no. 1 (February 1, 2021): 21–26. http://dx.doi.org/10.32964/tj20.1.21.
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Technology to apply suspensions of starch grains to the wet surface of paper, during the dewatering process, is reviewed. Though the technology is not new, it continues to attract the attention of papermakers as a means to increase bonding strength. Starch grains that are sprayed onto the wet-web of paper can be retained at levels exceeding what can be effectively added to the fiber suspension at the wet end. Unlike adding a starch solution at a size press, no additional drying capacity is required on the paper machine. To be effective, the starch needs to be able to swell and develop bonding during the paper drying process. Paperboard applications with recycled fibers appear to be a good fit. There is potential to increase bonding by processes that favor fuller gelatinization of the starch grains by the time the paper becomes dry.
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Gu, Yan, and Li Gu. "Exploration on Digital Teaching of industrial design course." E3S Web of Conferences 236 (2021): 05013. http://dx.doi.org/10.1051/e3sconf/202123605013.
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In the spring of 2020, affected by the new epidemic situation, the state called for "suspension of classes and no suspension of school", and encouraged schools to use the Internet and other informationbased means for teaching. Deepening the reform of China's higher education, actively exploring the teaching of industrial design under the digital background, and cultivating designers with innovative spirit and innovative ability are the responsibilities of industrial design teachers. Digital teaching mode emphasizes students' independent and innovative learning, which is easy to realize digital virtualization of learning environment, and provides students with more creative space and practical freedom. Teachers should combine the requirements and characteristics of industrial design courses, with the help of webbased network teaching platform, multimedia production tools and network programming tools to construct the system mode of digital teaching resources system for industrial design courses. Digital teaching provides an effective means for teachers to implement innovative education and build a platform for students to learn independently. Exploring the advantages of digital teaching, developing multimedia courseware and innovating multi-media teaching material database have become effective teaching means to cultivate students' ability and ensure the quality and sustainable development of industrial design talents.
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García-Pozuelo, D., V. Díaz, and M. J. L. Boada. "Improving Vehicle Safety: A New Methodology for Vehicle Steering System Inspection by Means of Forces Measure." Advances in Mechanical Engineering 6 (January 1, 2014): 870349. http://dx.doi.org/10.1155/2014/870349.
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Some mechanical systems, such as steering, brakes, and suspension, critically affect the safety of the vehicle. These systems are subject to wear through use and time, changing their status throughout the lifetime of a vehicle. It is, therefore, essential to develop adequate components and procedures of inspection that ensure the correct operation of these systems. Moreover, the steering inspection must guarantee certain requirements, such as, being able to test any vehicle steering system and being low priced. In addition, one of the most important requirements for any inspection procedure is to provide the measurements in a short time. This fact conditions the measurement process and sensors to be employed. The current steering system that measures the steering angles is time consuming. The aim of this research is to introduce a steering system inspection based on forces measured by means of a dynamometer plate. The main features of the proposed system ensure minimum testing time, and simple operation and avoid manipulation of the vehicle. In addition, precise and objective limits for acceptance and rejection have been established. Therefore, the proposed procedure meets all the requirements for the periodic motor vehicle inspection (PMVI).
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Kou, Farong, Qiangqiang Jing, Chen Chen, and Jianghao Wu. "Endocrine Composite Skyhook-Groundhook Control of Electromagnetic Linear Hybrid Active Suspension." Shock and Vibration 2020 (February 29, 2020): 1–17. http://dx.doi.org/10.1155/2020/3402168.
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In order to effectively improve vehicle riding comfort, handling stability, and realize vibration energy recovery, a new kind of electromagnetic linear hybrid active suspension (EMLHAS) integrated with linear motor and solenoid valve shock absorber is put forward. Firstly, for the analysis of the suspension performance, a quarter dynamic model of EMLHAS is established. At the same time, the mathematical models of a linear motor, including the active state and energy-regenerative state, are found. The correctness of mathematical models for the linear motor in the active and energy-regenerative states is verified by means of characteristic tests. Moreover, the velocity characteristic tests of solenoid valve shock absorber are carried out to determine its mathematical polynomial model in the semiactive state. Then, a new kind of multimode endocrine composite skyhook-groundhook control strategy is proposed. The suspension motion is divided into four modes according to the driving conditions of the vehicle. An endocrine control with long feedback and short feedback is combined with the skyhook-groundhook control. The control laws of the skyhook-groundhook controller and endocrine controller are, respectively, designed. Finally, the simulation analysis of suspension dynamic performance and energy-regenerative characteristic is done. The results show the control effect of endocrine composite skyhook-groundhook control is better than that of skyhook-groundhook control, which improves vehicle riding comfort and handling stability. Moreover, part of vibration energy is recovered.
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Qin, Yechen, Mingming Dong, Reza Langari, Liang Gu, and Jifu Guan. "Adaptive Hybrid Control of Vehicle Semiactive Suspension Based on Road Profile Estimation." Shock and Vibration 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/636739.
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A new road estimation based suspension hybrid control strategy is proposed. Its aim is to adaptively change control gains to improve both ride comfort and road handling with the constraint of rattle space. To achieve this, analytical expressions for ride comfort, road handling, and rattle space with respect to road input are derived based on the hybrid control, and the problem is transformed into a MOOP (Multiobjective Optimization Problem) and has been solved by NSGA-II (Nondominated Sorting Genetic Algorithm-II). A new road estimation and classification method, which is based on ANFIS (Adaptive Neurofuzzy Inference System) and wavelet transforms, is then presented as a means of detecting the road profile level, and a Kalman filter is designed for observing unknown states. The results of simulations conducted with random road excitation show that the efficiency of the proposed control strategy compares favourably to that of a passive system.
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Zhang, Wu, Yi Peng Lan, and Feng Ge Zhang. "Analysis and Optimization Design of Self Magnetic-Suspension Permanent Magnet Linear Synchronous Motor." Advanced Materials Research 383-390 (November 2011): 4762–67. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.4762.
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In order to eliminate the friction force of linear motor nc machine tool feed system and improve the machining precision, a new Self Magnetic-Suspension Permanent Magnet Linear Synchronous Motor(PMLSM)is putted forward in this paper, which can generate the suspending power by itself. In this paper, the magnetic field distribution is calculated by means of equivalent magnetizing current and Schwarz-christoffel transformation, and is further analyzed and verified by using Finite Element Method. Furthermore, the method of optimizating the length of the primary iron-cored is adopted to design the motor. The experimental results shows that self magnetic suspension -PMLSM can generate thrust and suspending force separately, and the thrust and suspending force are improved by applying optimized method.
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Prstic, Aurel, Zagorka Acimovic-Pavlovic, Ljubisa Andric, Jovica Stojanovic, and Anja Terzic. "Scientific paper zircon-based coating for the applications in Lost Foam casting process." Chemical Industry and Chemical Engineering Quarterly 18, no. 4-1 (2012): 587–93. http://dx.doi.org/10.2298/ciceq111122034p.
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In this work, a possibility to develop a new zircon-based refractory coating for casting applications was investigated. Optimization of the coating composition with controlled rheological properties was attained by application of different coating components, particularly by application of a new suspension agent and by alteration of coating production procedure. Zircon powder with particle size of 25x10-6 m was used as filler. The zircon sample was investigated by means of the following methods: X-ray diffraction analysis, diffraction thermal analysis and polarized microscope. The shape and grain size were analyzed by means of the PC program package OZARIA 2.5. It was shown that application of this type of water-alcohol-based coating had a positive influence on surface quality, structural and mechanical properties of the castings of cast iron obtained by pouring into sand molds by means of the expandable patterns method (Lost Foam casting process).
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Szepanski, Christian, Jana Grosse-Brauckmann, and Christos Argirusis. "Electrophoretic Deposition as Preparation Method for Intermediate Temperature SOFC Half Cells." Key Engineering Materials 412 (June 2009): 209–14. http://dx.doi.org/10.4028/www.scientific.net/kem.412.209.
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In this study we present the preparation of SOFC half cells by electrophoretic deposition. The cathode is deposited from a methyl ethyl ketone (MEK) suspension on dense apatite type lanthanum silicate (ATLS) pellets using a constant voltage. ATLS are a new class of electrolytes, which provides good oxygen permeability even at temperatures below 800°C. As cathode materials we used La2Ni0.8Cu0.2O4+δ (LNC) and La0.8Sr0.2Ni0.6Fe0.4O3 (LSNF). A conductive layer on the ATLS material was used to provide the necessary conductivity for electrophoretic deposition (EPD) process. For the preparation of suitable suspensions the charging behaviour and particle size of the different powders were investigated by means of zeta-potential and laser scattering measurements. When the electrophoretic mobility of the suspended particles was not sufficient iodine was added. Deposition kinetics were determined prior to preparation of the half cells. EPD parameters as well as sintering conditions were optimized in order to gain well adhering porous cathode layers.
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Kijo-Kleczkowska, Agnieszka. "Analysis of coal suspensions evolution during combustion process." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 5 (July 24, 2019): 2551–61. http://dx.doi.org/10.1108/hff-03-2019-0200.
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Purpose The paper aims to undertake coal–water suspension combustion, in air and in fluidised bed conditions. Fluidised bed conditions are the best to efficiently and ecologically use fuel. Combustion technologies using coal–water fuels create a number of new possibilities for organising combustion processes so that they fulfil contemporary requirements. The aim of the process was to show how the specificity of combustion of coal–water suspensions in the fluidised bed changes the kinetics of the process, compared to combustion in the air stream. Changes of the surface and the centre temperature and mass of the coal suspension during combustion, and evolution of fuels during process are presented in the paper. Design/methodology/approach Experimental character of the research required the research stand preparation, as well as working out of the measurements methodology (Kijo-Kleczkowska, 2010). The research stand (Figure 1a) was made of ceramic blocks in which the quartz pipes were put. The heating element of the stand comprised three heating coils of 2.0 kW. Each heater was placed in small quartz tubes. These tubes were built into the quartz tube which was thermally insulated by fibre material Al2O3 and which was covered with steel sheet. Combustion chamber constituted the quartz pipe, which was additionally insulated thermally, to keep the necessary temperature of the entering gas and to reduce the heat loss. The compressed air was transported to the quartz tube through the electro-valve, the control valve and the rotameter. This study stand allowed for the comparison of the combustion process of coal–water suspensions, in air and in fluidised bed conditions. To study in the fluidised bed, quartz sand was used. Depending on the velocity of air inflowing from the bottom of the bed, different bed characteristics were obtained – from bubble – to circulating-beds. The fumes were removed outside by means of a fan fume cupboard. To regulate the temperature inside the combustion chamber, the Lumel microprocessor thermoregulator was applied. The regulator controlled the work of tri-phase Lumel power controller supplying the main heating elements (gas heater) allowing to measure the actual temperature with accuracy of measurements to 20°C. The temperature measurements in the combustion chamber were carried out by means of the thermocouple NiCr-NiAl. To establish the centre and surface temperature and mass of the fuel, a special instrument stalk was constructed (Figure 1b). It had two thermocouples PtRh10-Pt, placed in two thin quartz tubes connected to the scale. One of the thermocouples was located inside the fuel, while the other served as a basket which was to support the fuel. It also touched the surface of the fuel. The thermocouples were connected to the computer to record the experimental results. The essential stage of the preliminary work was to make out a suspension, which was a mixture of fuel dust (hard coal dust or dried coal-sludge dust) and water. To produce the suspension it was necessary to prepare fuel dust after grinding and sifting it, and then adding water, to obtain a suspension moisture of 20, 35 or 50 per cent. The hard coal was applied in the research. The analysis of fuel dust (in air-dry state) is shown in Table I. The testing of the porosity of fuel was made with mercury porosimetry, carried out in the Pascal 440 apparatus, applying pressure from 0.1 to 200 MPa. This method involves the injection of mercury into the pores of the fuel, using high pressures (Kijo-Kleczkowska, 2010). Findings 1. Under experimental conditions, during combustion in the fluidised bed, intensive heating of the suspension is observed in the initial stage of the process, followed by the removal of heat from the suspension by the contacting quartz material, leading to lowering of the average fuel temperature and extension of the combustion time, compared to the process carried out in air. 2. Measurements using mercury porosimetry enable the identification of the change of suspension porosity. 3. Devolatilisation and combustion of volatiles lead to an increase in the pores’ size in the fuel and their coalescence. 4. Combustion of fuel leads to the development of cracks in the suspension, and its structure changes under the influence of temperature. Cracks are caused by the formation of thermal stresses inside the fuel. 5. Under experimental conditions, suspension combustion in the fluidised bed causes an increase in volume participation of pores, with larger sizes of pores (3,500-5,000 nm), compared to combustion in the air. Originality/value The paper undertakes the evolution of suspension fuel, made of a hard coal and a coal-sludge, during combustion in air and in the fluidised bed.
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Prasetya, Fajar, Supriatno Salam, Agung Rahmadani, Kansy Haikal, Lizma Febrina, Hady Anshory, Muhammad Arifuddin, et al. "Novel Amides Derivative with Antimicrobial Activity of Piper betle var. nigra Leaves from Indonesia." Molecules 26, no. 2 (January 11, 2021): 335. http://dx.doi.org/10.3390/molecules26020335.
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Piper betle var. nigra is a tropical plant closely related to the common piper. P. betle has also been dubbed a promising source of natural antioxidants in herbal health products, antibacterial, antifungal, antimalarial, cytotoxic activity against the cancer cell lines K562 and HL-60, and antileishmanial. The aim of this study to observation Antimicrobial activity and isolation of chemical compound. The antimicrobial activity of P. betle extract was performed by well diffusion method against two oral pathogenic bacteria (Streptococcus mutans and Streptococcus sanguinis) and opportunistic pathogenic yeast (Candida albicans). The inoculum (bacterial and yeast suspension) was prepared from a 24-h culture on NB for bacterial suspension and on TSB for yeast suspension. Extraction and isolation using various method of chromatography. Isolated compounds were characterized by spectroscopic means. Our study showed antimicrobial activity from crude ethanol extract of leaves P. betle L. var. nigra against two oral pathogenic bacteria and opportunistic pathogenic yeast with concentration 0.5% and 1%. The first report of two new amides derivatives, piperenamide A (1) and piperenamide B (2) in P. betle L. var. nigra.
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Prasetya, Fajar, Supriatno Salam, Agung Rahmadani, Kansy Haikal, Lizma Febrina, Hady Anshory, Muhammad Arifuddin, et al. "Novel Amides Derivative with Antimicrobial Activity of Piper betle var. nigra Leaves from Indonesia." Molecules 26, no. 2 (January 11, 2021): 335. http://dx.doi.org/10.3390/molecules26020335.
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Piper betle var. nigra is a tropical plant closely related to the common piper. P. betle has also been dubbed a promising source of natural antioxidants in herbal health products, antibacterial, antifungal, antimalarial, cytotoxic activity against the cancer cell lines K562 and HL-60, and antileishmanial. The aim of this study to observation Antimicrobial activity and isolation of chemical compound. The antimicrobial activity of P. betle extract was performed by well diffusion method against two oral pathogenic bacteria (Streptococcus mutans and Streptococcus sanguinis) and opportunistic pathogenic yeast (Candida albicans). The inoculum (bacterial and yeast suspension) was prepared from a 24-h culture on NB for bacterial suspension and on TSB for yeast suspension. Extraction and isolation using various method of chromatography. Isolated compounds were characterized by spectroscopic means. Our study showed antimicrobial activity from crude ethanol extract of leaves P. betle L. var. nigra against two oral pathogenic bacteria and opportunistic pathogenic yeast with concentration 0.5% and 1%. The first report of two new amides derivatives, piperenamide A (1) and piperenamide B (2) in P. betle L. var. nigra.
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Bonci, Po, Pa Bonci, and A. Lia. "Suspension Made with Amniotic Membrane: Clinical Trial." European Journal of Ophthalmology 15, no. 4 (July 2005): 441–45. http://dx.doi.org/10.1177/112067210501500403.
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Purpose To investigate if a suspension made with amniotic membrane could have a beneficial effect on ocular surface diseases. Methods In the Imola branch of the Eye Bank of Emilia Romagna, the authors prepared a suspension containing homogenized amniotic membrane previously conserved at −80 degrees Celsius. Subsequently, the authors gave this preparation to 21 patients: 8 had undergone lamellar keratoplasty, 4 had undergone penetrating keratoplasty, 2 had undergone photorefractive keratectomy with a delay of epithelialization, 3 had neurotrophic corneal ulcers, 2 had corneal burning, 1 had torpid corneal ulcer, and 1 had Sjögren syndrome. Each patient had been treated with conventional therapy for at least, 4 months without any clinical improvement. In this sample of eyes the authors evaluated the transparency and integrity of epithelium before and after the therapy by means of a fluorescein staining test, examining the area of epithelial defect as well as the phlogistic situation and the symptoms referred by patients. Nine eyes from this group of patients were studied by impression cytology before and after 3 months of use of suspension. The follow-up was 5 months of once-weekly visits. Results In all patients, after 15 to 30 days the corneas became negative to fluorescein staining test and the epithelium seemed more complete and regular, there was an evident decrease of phlogistic situation in the conjunctiva, and an improvement of symptoms was referred by patients. The situation was stable during the whole follow-up. No side effects were noted. The impression cytology repeated 3 months after the treatment showed a significant corneal recovery of the cytologic situation with an important decrease of CK19 + cells on the corneal surface. Conclusions This new therapy, which is less traumatic than an implant of amniotic membrane, is safe, and can be repeated for a long period, could help patients with corneal superficial defects.
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Prstić, A., Z. Aćimović-Pavlović, A. Terzić, and L. Pavlović. "Synthesis and Characterization of New Refractory Coatings Based on Talc, Cordierite, Zircon and Mullite Fillers for Lost Foam Casting Process." Archives of Metallurgy and Materials 59, no. 1 (March 1, 2014): 89–95. http://dx.doi.org/10.2478/amm-2014-0015.
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Abstract Refractory coatings based on different refractory fillers (talc, cordierite, zircon and mullite) for application in Lost Foam casting process were investigated. Design and optimization of the coatings composition with controlled, rheological properties included, and consequently synthesis were achieved by application of different coating components, namely different suspension agents and fillers and by alteration of the coating production procedure. Morphologic and microstructural analysis of fillers was carried out by means of scanning electronic microscope. X-ray diffraction analysis by means of X-ray diffractometer was applied in determination and monitoring the phase composition changes of the refractory fillers. An analysis of the particle size and shape was carried out by means of the PC software application package OZARIA 2.5. To assess the effects of application of individual refractory coatings, a detailed investigation of structural and mechanical properties of the moldings obtained was performed. Highlight was placed on revealing and analyzing surface and volume defects present on moldings. Radiographic molding tests were carried out by means of the X-ray device SAIFORT type-S200. Attained results are essential for the synthesis of refractory coatings based on high-temperature fillers and their applications in Lost Foam casting process for manufacturing of moldings with in-advance-set properties.
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Moradi Nerbin, Mohammad, Reza Mojed Gharamaleki, and Mehdi Mirzaei. "Novel optimal control of semi-active suspension considering a hysteresis model for MR damper." Transactions of the Institute of Measurement and Control 39, no. 5 (December 16, 2015): 698–705. http://dx.doi.org/10.1177/0142331215618446.
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In this paper, a new form of the Bouc–Wen model is identified. This model, which includes hysteresis loop, is suitable to use in controller design. The modified Bouc–Wen model is employed as an experimental model to identify the new model. Evaluation of the proposed model illustrated that this model has good accuracy in small velocity area. A novel approach of model predictive control is employed to derive the control input or magneto-rheological damper current, with respect to constraints. This controller gives analytical control law by means of the Karush–Kuhn–Tucker (KKT) optimization method in order to solve the constrained optimization problem. One of the main advantages of this controller is its analytical form, which allows easy implementation of the controller, and this special form leads to rapid calculation of the control input. Simulations show that the proposed control strategy establishes an appropriate trade-off between suspension criteria, including ride comfort and road holding.
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Zhang, Yun Ran, Ming Ding, Zhi Shen Jiang, Luo Lan Ke, and Ming Hua Li. "Synthesis, Characterization and Suspension Stability of Al2O3 Nanoparticles Functionalized by Polyurethane." Materials Science Forum 852 (April 2016): 480–84. http://dx.doi.org/10.4028/www.scientific.net/msf.852.480.
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In this paper, we have synthesized new functionalized Al2O3 nanoparticles successfully via reaction, which was grafted polyurethane onto the surface of nanoparticles dispersed in n-butyl acetate. The structure, surface properties, and thermal stability of the functionalized Al2O3 nanoparticles were characterized by means of by FT-IR, TGA and SEM. The results showed that the surface of Al2O3 nanoparticles has been grafted with polyurethane (PU). Furthermore, Al2O3 nanoparticles was dispersed evenly in the organic solvent, which can show a long suspension stability near to 6 months without precipitation, indicating that this product is very useful to prepare stabilized coating nanocomposites.
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Wang, Hong Jie, and Shan Shan Liu. "Study on Coating and Technological Conditions of LLM-105." Advanced Materials Research 328-330 (September 2011): 1161–66. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1161.
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For the study of new insensitive energetic material LLM-105`s coating and techniques, by means of theory analysis through the interface, calculation of the contact angle test, verified that EPDM can coat LLM-105. Booster samples were prepared by adopting water suspension method with EPDM is the adhesive. And the coating’s optimal technological condition is also be verified. The results showed that, the obtained LLM-105/EPDM booster can be coated better. The final results of the improved optimal technological condition is with vacuum degree is 0.03mpa, stirring speed is 430r/min, dropping speed is 0.06ml/min.
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Ricca, Michela, Emilia Le Pera, Maurizio Licchelli, Andrea Macchia, Marco Malagodi, Luciana Randazzo, Natalia Rovella, Silvestro A. Ruffolo, Maduka L. Weththimuni, and Mauro F. La Russa. "The CRATI Project: New Insights on the Consolidation of Salt Weathered Stone and the Case Study of San Domenico Church in Cosenza (South Calabria, Italy)." Coatings 9, no. 5 (May 22, 2019): 330. http://dx.doi.org/10.3390/coatings9050330.
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This paper presents the results of a laboratory experimentation carried out on stone materials in the framework of the CRATI project (Knowledge and Restoration through Advanced Integrated Technologies) aimed at testing new products with consolidating properties by means of an integrated methodological approach. After the preliminary characterization of stone materials collected in the pilot site, the second stage of the activities within the project were focused on the formulation and testing of products for the conservation of the same materials against decay, especially salt crystallization, one of the most aggressive and common degrading processes. The San Domenico Church, located in the old town of Cosenza (Calabria, Southern Italy) has been chosen as the pilot site and for the in situ tests. Several specimens with the same features of the stone materials used in San Domenico church were collected from a historical quarry near the city of Cosenza. These specimens were treated and then artificially degraded by salt crystallization tests in order to evaluate their susceptibility to weathering intensity. Three different consolidating products were used; respectively, two commercial and another one formulated in laboratory: (a) a suspension of nanosilica (Nano Estel®); (b) a suspension of nanolime (CaLoSiL®), and (c) a suspension of nano calcium-hydroxide dispersed in isopropyl alcohol and then mixed with diammonium hydrogen phosphate. A systematic approach, including minero-petrographic, geochemical and physico-mechanical techniques, was applied to evaluate (a) the nature and main features of materials; (b) the efficacy of consolidating treatments, and (c) the resistance of treated stone to the salt crystallization processes. The tested products demonstrated a significant efficiency to consolidate and protect stone material samples, enhancing their resistance to salt crystallization. Thus, such a case history may be useful in order to plan appropriate restoration interventions that consider the interactions between the building stone and the protective/consolidating product.
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Szlendak, Jerzy K., Agnieszka Jablonska-Krysiewicz, and Dariusz Tomaszewicz. "Analytical modelling of a three-layer wall system of strengthening for large-panel slab buildings by means of bonded anchors." MATEC Web of Conferences 174 (2018): 04012. http://dx.doi.org/10.1051/matecconf/201817404012.
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The goal of the article is to elaboration analytical models describing a new system of reinforcing three-layer walls of large-panel buildings with bonded anchors. The use of this type of fasteners that bond the façade texture layer to the structural slab is necessary due to the low durability of previously used suspension elements. Various bonded anchorage systems were considered. The new anchorage systems were designed as two-anchors systems (horizontal anchor and diagonal anchors) and three-anchors systems (horizontal anchor and two diagonal anchors). The inclinations of these anchors are in the range of 30°-60° in relation to the surface of the element. For the above types of reinforcements, analytical models have been developed that take into account the change of strength parameters of the resin and steel from which the anchors were made, the interaction of materials resin-steel and resin-concrete and the effect of the simultaneous action of pull-out and shearing forces. Moreover, was assumed the simultaneous destruction of fasteners two- and three-anchors. The elaborated analytical models will be used to determine the load-bearing capacity of the new connector system, which will allow the elaboration of guidelines for strengthening three-layer walls of largepanel slab buildings.
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Kosukhin, Mikhail M., Andrei M. Kosukhin, and Irina V. Starostina. "Improving the Bio-Resistance of Cement Concretes by Means of Fungicidal Poly-Functional Modifiers." Solid State Phenomena 299 (January 2020): 143–49. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.143.
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The research findings of physical and chemical properties of heavy and light concretes, contaminated with water suspension of mold fungi spores, are presented. It is noted that the concretes’ funginertness (resistance to fungi) is significantly influenced by their age, porosity and the alkalinity of medium. In the course of time the strength of concrete decreases, which is conditioned by the activation of mold fungi growth processes, as a result of de-alkalization of concrete, due to carbonization of cement stone and release of organic acids into the material. To improve the concrete’s resistance in biologically aggressive media, it is suggested to modify concrete with a new poly-functional fungicidal modifier, obtained on the basis of resorcine production waste. It has been demonstrated that the addition of resorcinol-formaldehyde oligomers to concrete mix completely inhibits mold fungi growth and allows obtaining concretes with the increased density and strength, which can be used in conditions of biologically aggressive media. The strength characteristics of the cement stone with the researched modifiers are not reduced at mold fungi spores’ contamination, but, on the contrary, slightly increase, due to the increase of cement paste fluidity, decrease of W/C ratio, reduction of micro-cracks in concrete and compaction of its structure, due to the peptizing action of the modifier.
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Metin, Muzaffer, and Rahmi Guclu. "Rail Vehicle Vibrations Control Using Parameters Adaptive PID Controller." Mathematical Problems in Engineering 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/728946.
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In this study, vertical rail vehicle vibrations are controlled by the use of conventional PID and parameters which are adaptive to PID controllers. A parameters adaptive PID controller is designed to improve the passenger comfort by intuitional usage of this method that renews the parameters online and sensitively under variable track inputs. Sinusoidal vertical rail misalignment and measured real rail irregularity are considered as two different disruptive effects of the system. Active vibration control is applied to the system through the secondary suspension. The active suspension application of rail vehicle is examined by using 5-DOF quarter-rail vehicle model by using Manchester benchmark dynamic parameters. The new parameters of adaptive controller are optimized by means of genetic algorithm toolbox of MATLAB. Simulations are performed at maximum urban transportation speed (90 km/h) of the rail vehicle with ±5% load changes of rail vehicle body to test the robustness of controllers. As a result, superior performance of parameters of adaptive controller is determined in time and frequency domain.
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Radić, Nikola, Vlado Radić, and Biljana Grujić. "Economic impact of the coronavirus pandemic on air traffic." Ekonomika 67, no. 2 (2021): 59–68. http://dx.doi.org/10.5937/ekonomika2102059r.
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The coronavirus pandemic is an unprecedented event in modern history, not only of aviation, but also of humanity. The negative consequences of the pandemic are not only related to the suspension of flights and the inability to transport passengers, but also have a great impact on other industries, such as the production of aircraft, systems and engines, tourism, the food industry, etc. The suspension of flights has led to many times lower revenues than planned, the dismissal of a large number of employees in this industry, as well as the cancellation of new airplanes ordered. Also, the prescribed health care measures that airlines must apply will affect a smaller number of passengers on planes, which means that each flight will be less cost-effective. Faced with large losses, airlines must organize in order to achieve maximum efficiency and a partial return to the levels of flying and transportation of people and goods that were achieved during 2019. The paper analyses the state and importance of the global aviation industry, the impact of the pandemic on business results and solving the problems of airlines.
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Hashchuk, P., and S. Nikipchuk. "HARD-SOFT TECHNOLOGY OF INFORMATION SUSPENSION PROCESS OF MODELING OF HEAT GENERATION/HEAT CONSUMPTION IN THE INTERNAL COMBUSTION ENGINE." Bulletin of Lviv State University of Life Safety, no. 18 (December 31, 2018): 6–22. http://dx.doi.org/10.32447/20784643.18.2018.01.
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Deterministic and, in a certain sense, "linear" interpretation of the world often leads to the recognition of the fact that the more accurate model we need, the more complex it must be (as in case of a formalized reproduction of the real system, or the implementation of the desired system properties in the process of formal synthesis of something new). Instead, following the principle of synergy leads to the conviction that there is always a certain model of optimal complexity e.g. in the synthesis of the new system, and in the analysis of real system peculiarities. However, the model of reality could be a part of this reality that is included to the carefully structured formal description. Since we cannot penetrate into the working space of the serial engine while testing, we should use a test engine of a special construction when the working space corresponds to the laws of similarity and this engine will serve as a model of the working space of the serial engine.
The study illustrates the effectiveness of hard-soft technology while investigating the peculiarities of heat generation and heat consumption in the internal combustion engine, which will combine mathematic and algorithmic means of modelling as well as the means of real simulation. The necessity of hard-soft technology introduction arises from the excessive complexity of thermal phenomena occurring in the internal combustion engine (ICE), and the inability to fully subordinate these phenomena to existing analytical models.
The combination of original and analytical properties, reality and virtual reality while modelling the processes in internal combustion engines allows us to substantially improve the quality of information in the process of design and engine construction. Taking this into consideration, there are some natural grounds to apply principles of heuristic self-organization, self-learning, means of the neural networks, etc. in the design implementation.
The study demonstrates the example of modelling the real working space of ICE with the forced start that serves as a supplement to the mathematical algorithmic two-zone model of heat generation / heat consumption / heat extraction.
The basic information that can be obtained by means of hard-soft technology in the framework of, for example, the two-zone model of the work process in the gasoline engine, is the variability with the change in the angle of rotation of the crankshaft of the engine: absolute pressure (indicative diagram); absolute temperature; heat transmitted inside the cylinder between zones; coefficient of excess air; coefficient of heat transfer; intensity of heat extraction in the process of combustion of fuel; intensity of heat transfer through the walls of the cylinde
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Rodríguez Licea, Martín Antonio, Edgar Armando Vazquez Rodríguez, Francisco Javier Perez Pinal, and Juan Prado Olivares. "The Rollover Risk in Delta Tricycles: A New Rollover Index and Its Robust Mitigation by Rear Differential Braking." Mathematical Problems in Engineering 2018 (October 17, 2018): 1–14. http://dx.doi.org/10.1155/2018/4972419.
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Although there are efforts to electrify and diversify small vehicles, active safety on motorcycles and tricycles (also known as auto rickshaw, tuk-tuk, mototaxi, etc.) has been relegated until a few years ago. For instance, the electric tricycles (even the combustion ones) marketed today do not have an active safety system that prevents or mitigates the risk of rollover, despite how prone they are to such a situation. The concern for the increase in its marketing is latent and, unfortunately, there are very few related studies. In this article, we present the obtaining and validation of a new rollover index for tricycles demonstrating its effectiveness in predicting and detecting the risk, even statically, by means of a simple quantity. In addition, a controller for the mitigation of the risk of rollover is presented which, by means of a Lyapunov type analysis, it is shown to be robust to changes in parameters, such as the center of gravity height, using a polytopic representation of the system and a differential braking strategy on the rear wheels. Numerical simulations, including video simulation captures, of the operation of the rollover mitigation system using widely recognized commercial software, are also presented. This work can be extended to vehicles with a suspension system or for trikes without autocamber.
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Saber, Fatima Ezzahra, Mohamed Ouahi, and Abdelmjid Saka. "Unknown Road Profile Input Estimation with Two Levels of Complexity Models." International Journal of Engineering Research in Africa 50 (September 2020): 113–30. http://dx.doi.org/10.4028/www.scientific.net/jera.50.113.
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Most advanced driver assistance systems (ADAS) are intended to improve ride comfort for vehicle suspension systems. A new road estimation method is proposed as a means of observing the road profile level. To achieve this, two complexity levels (quarter car and half car models) are presented and developed in Matlab to analyze the vertical vibration of a vehicle. The unknown input observers are then designed for observing unknown states and road profile level. The necessary measurements are the accelerations of the centers of the wheels. The results of simulations conducted with random road excitation show successfully simulated experimentations of the method using a realistic simulator as well as its robustness.
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Andric, Tomislav, and Jan Harms. "Lightsaber: A Simulator of the Angular Sensing and Control System in LIGO." Galaxies 9, no. 3 (September 5, 2021): 61. http://dx.doi.org/10.3390/galaxies9030061.
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The suspended test masses of gravitational-wave (GW) detectors require precise alignment to be able to operate the detector stably and with high sensitivity. This includes the continuous counter-acting of seismic disturbances, which, below a few Hertz, are not sufficiently reduced by the seismic isolation system. The residual angular motion of suspended test masses is further suppressed by the Angular Sensing and Control (ASC) system. However, in doing so, the angular motion can be enhanced by the ASC at higher frequencies where the seismic isolation system is very effective. This has led to sensitivity limitations between about 10 Hz and 25 Hz of the LIGO detectors in past observation runs. The observed ASC noise was larger than simple models predict, which means that more accurate detector models and new simulation tools are required. In this article, we present Lightsaber, a new time-domain simulator of the ASC in LIGO. Lightsaber is a nonlinear simulation of the optomechanical system consisting of the high-power cavity laser beam and the last two stages of suspension in LIGO including the ASC. The main noise inputs are power fluctuations of the laser beam at the input of the arm cavities, read-out noise of sensors used for the ASC, displacement noise from the suspension platforms, and noise introduced by the suspension damping loops. While the plant simulation uses local degrees of freedom of individual suspension systems, the control is applied on a global angular basis, which requires a conversion between the local and global bases for sensing and actuation. Some of the studies that can be done with this simulation concern mis-centering of the beam-spot (BS) position on the test masses, the role of laser power fluctuations for angular dynamics, and the role of the various nonlinear dynamics. The next important step following this work will be a detailed comparison between Lightsaber results and data from the control channels of the LIGO detectors.
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Smirnova, Vera B., Anton V. Proskurnikov, and Natalia V. Utina. "New results on cycle–slipping in pendulum–like systems." Cybernetics and Physics, Volume 8, 2019, Number 3 (November 30, 2019): 167–75. http://dx.doi.org/10.35470/2226-4116-2019-8-3-167-175.
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n this paper, we examine dynamics of multidimensional control systems obtained as feedback interconnections of stable linear blocks and periodic nonlinearities. The simplest of such systems is the model of mathematical pendulum (with viscous friction), so we call such systems pendulum-like. Other examples include, but are not limited to, coupled vibrating units, networks of oscillators, Josephson junction arrays and numerous synchronization circuits used in radio and telecommunication engineering. Typically, a pendulum-like system has infinite sequence of equilibria, and one of the central problems addressed in the theory of such systems is to find the conditions of “global stability”, or gradient-like behavior ensuring that every solution converges to one of the equilibria points. If a system is gradient-like, another problem arises, being the main concern of this paper: can we find the terminal equilibrium, given the initial condition of the system? It is well known that solutions do not converge, in general, to the nearest equilibrium; this phenomenon is known as cycle-slipping. For a pendulum, cycle-slipping corresponds to multiple rotations of the pendulum about its suspension point. In this paper, we estimate the number of slipped cycles for general pendulum-like systems by means of periodic Lyapunov functions and the Kalman-Yakubovich-Popov lemma.
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Wang, Xiaoguang, Yunbo Hu, and Qi Lin. "Workspace analysis and verification of cable-driven parallel mechanism for wind tunnel test." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 231, no. 6 (May 12, 2016): 1012–21. http://dx.doi.org/10.1177/0954410016646601.
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Cable-driven parallel mechanism is a special kind of parallel robot in which traditional rigid links are replaced by actuated cables. This provides a new suspension method for wind tunnel test, in which an aircraft model is driven by a number of parallel cables to fulfil 6-DOF motion. The workspace of such a cable robot is limited due to the geometrical and unilateral force constraints, the investigation of which is important for applications requiring large flight space. This paper focuses on the workspace analysis and verification of a redundant constraint 6-DOF cable-driven parallel suspension system. Based on the system motion and dynamic equations, the geometrical interference (either intersection between two cables or between a cable and the aircraft) and cable tension restraint conditions are constructed and analyzed. The hyperplane vector projection strategy is used to solve the aircraft’s orientation and position workspace. Moreover, software ADAMS is used to check the workspace, and experiments are done on the prototype, which adopts a camera to monitor the actual motion space. In addition, the system construction is designed by using a built-in six-component balance to measure the aerodynamic force. The results of simulation and tests show a good consistency, which means that the restraint conditions and workspace solution strategy are valid and can be used to provide guidance for the cable-driven parallel suspension system’s application in wind tunnel tests.
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Dodero, Danilo, and Luca Bernardini. "The Use of Tutomesh for a Tension-Free and Tridimensional Repair of Uterovaginal and Vaginal Vault Prolapse: Preliminary Report." Surgery Research and Practice 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/303679.
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Objective. To evaluate efficacy in terms of vaginal capacity, coital function, and recurrence prevention of a new biological mesh of bovine pericardium (Tutomesh) in the repair of severe POP.Methods. Thirty cases of patients suffering from stage III uterine or apical prolapse undergone surgical repair by means of a modified sacrospinous ligament suspension combined with mesh attachment to both the cardinal ligaments, posterior and anterior colporrhaphy, and perineal body fixation. The mesh was replaced inside the pelvis with the goal of reconstructing the tridimensional fascial disposition of the structures sustaining the correct axis of vagina. Follow-up was done at 12 months with POPIQ analysis.Results. One total mesh failure occurred early after surgery due to marked deficiency of anatomy. Two cystoceles were observed at 12 months in two patients treated for apical prolapse where anterior repair was not performed. Two other patients developed a de novo SUI at 12 months. No reported abnormalities of coital function or dyspareunia were ever found after surgery.Conclusions. It is possible that the utilization of a tension-free and tridimensional placement of Tutomesh might favor a more physiologic reconstruction of the vaginal axis as compared with traditional sacrospinous ligament suspension.
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Radić, M., N. Ignjatović, Zoran Nedić, M. Mitrić, Dejan Miličević, and Dragan P. Uskokovic. "Synthesis and Characterization of Biphasic Calcium Phosphate/ Poly-(DL-Lactide-Co-Glycolide) Biocomposite." Materials Science Forum 494 (September 2005): 537–42. http://dx.doi.org/10.4028/www.scientific.net/msf.494.537.
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In this paper we report the results on synthesis of a composite biomaterial based on biphasic calcium phosphate (BCP) and poly-(DL-lactide-co-glycolide) (DLPLG). Besides, we have investigated the influence of new synthesis method on the structure and characteristics of the composite. The synthesis of biphasic calcium phosphate from Ca(NO3)2 x 4H2O and (NH4)3 PO4 in alkali environment was performed by means of precipitation technique. Composite material BCP/DLPLG was first prepared from commercial granules using chemical methods. Powdered polymer DLPLG was then homogenized at appropriate ratio with addition of biphasic calcium phosphate into the suspension. All samples were characterized by DSC, IR, X-Ray and SEM techniques.
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Xu, Wen Tao, Tong Chen Miao, and Zheng Liu. "An Efficient Multi-Objective Optimization Method for Complicated Vehicle Random Vibration." Applied Mechanics and Materials 94-96 (September 2011): 1694–700. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1694.
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In this paper, a new approach is proposed and addressed for designing vehicle suspension systems based on the scheme of multi-objective programming. For complicated vehicle random vibration, a linear model is used to describe the dynamic behavior of vehicles running on randomly profiled roads. The road irregularity is regarded as a Gaussian random process. Pesudo excitation method has been used to solve the dynamic responses. And a Kriging model is introduced to build the approximate mapping relationship between the design variables and the responses. Optimal solutions are derived by means of the method of centers for structural optimization with multiple objectives. Numerical examples are given, and compared with other optimization methods.
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Gao, H., L. Jézéque, E. Cabrol, and B. Vitry. "Robust Design of Suspension System with Polynomial Chaos Expansion and Machine Learning." Science & Technique 19, no. 1 (February 5, 2020): 43–54. http://dx.doi.org/10.21122/2227-1031-2020-19-1-43-54.
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During the early development of a new vehicle project, the uncertainty of parameters should be taken into consideration because the design may be perturbed due to real components’ complexity and manufacturing tolerances. Thus, the numerical validation of critical suspension specifications, such as durability and ride comfort should be carried out with random factors. In this article a multi-objective optimization methodology is proposed which involves the specification’s robustness as one of the optimization objectives. To predict the output variation from a given set of uncertain-but-bounded parameters proposed by optimization iterations, an adaptive chaos polynomial expansion (PCE) is applied to combine a local design of experiments with global response surfaces. Furthermore, in order to reduce the additional tests required for PCE construction, a machine learning algorithm based on inter-design correlation matrix firstly classifies the current design points through data mining and clustering. Then it learns how to predict the robustness of future optimized solutions with no extra simulations. At the end of the optimization, a Pareto front between specifications and their robustness can be obtained which represents the best compromises among objectives. The optimum set on the front is classified and can serve as a reference for future design. An example of a quarter car model has been tested for which the target is to optimize the global durability based on real road excitations. The statistical distribution of the parameters such as the trajectories and speeds is also taken into account. The result shows the natural incompatibility between the durability of the chassis and the robustness of this durability. Here the term robustness does not mean “strength”, but means that the performance is less sensitive to perturbations. In addition, a stochastic sampling verifies the good robustness prediction of PCE method and machine learning, based on a greatly reduced number of tests. This example demonstrates the effectiveness of the approach, in particular its ability to save computational costs for full vehicle simulation.
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Koryahin, Viktor, and Oksana Blavt. "Development of Distance Technologies in Physical Education of Students: Opportunities and Challenges." Journal of Learning Theory and Methodology 2, no. 1 (February 5, 2021): 5–11. http://dx.doi.org/10.17309/jltm.2021.1.01.
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Purpose. To identify the state of teaching “Physical Education” by means of distance technologies at the university. Materials and methods. The study involved 3,726 first-year students of the Lviv Polytechnic National University of all educational-and-scientific institutes. The organization of the study was aimed at studying the opinion of students on various issues regarding the quality of distance education in physical education. At the empirical level of the study, a questionnaire was used. Results. The study analyzed the state of physical education at the university by means of distance learning. According to the results of the survey, it was found that the vast majority of surveyed students (81.3%) believe that physical education classes by means of distance learning are necessary in the conditions of introduction of quarantine safety measures. 51.6% of students noted that methodical skills gained during the classes significantly helped them in organizing independent physical training sessions during the suspension of educational activities in auditoriums. 71% support the possibility of physical education classes by means of distance technologies in order to counteract the forced restriction of motor activity. Conclusions. Ensuring the effectiveness of physical education of students in the position of quarantine measures requires new approaches and methods of interaction with students, adequate choice of goals and objectives, organizational forms, methods and means of physical education maintain the proper level of their motor activity and prevent social maladaptation. From the study, we can conclude that physical education by means of distance technologies is in a state of development, but not at such a rapid pace. Instead, on the basis of the study summarizes that the use of distance learning means in physical education of students ensures the formation of values of a healthy lifestyle and maintaining their health at the appropriate level.
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Polášek, Pavel. "INFLUENCE OF VELOCITY GRADIENT ON OPTIMISATION OF THE AGGREGATION PROCESS AND PHYSICAL PROPERTIES OF FORMED AGGREGATES: Part 1. Inline high density suspension (IHDS) aggregation process." Journal of Hydrology and Hydromechanics 59, no. 2 (June 1, 2011): 107–17. http://dx.doi.org/10.2478/v10098-011-0009-5.
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INFLUENCE OF VELOCITY GRADIENT ON OPTIMISATION OF THE AGGREGATION PROCESS AND PHYSICAL PROPERTIES OF FORMED AGGREGATES: Part 1. Inline high density suspension (IHDS) aggregation processThis paper deals with optimisation and acceleration of the clarification process. It was established that both these objectives are closely inter-related and can be accomplished by the formation of aggregates with a high agitation intensity until the flocculation optimum is reached. This is a new method of formation of aggregates which is called the Inline High Density Suspension (IHDS) formation process. Further, under the IHDS process the aggregates are formed with a single root-mean-square velocity gradientG>> 50 s-1. It was also established that the process of formation of aggregates (expressed by residual e of the observed determinant) passes through a minimum. This minimum is considered to be the flocculation optimum. Furthermore, the agitation intensity (G) was found to be the inherent means influencing compactness and thereby density of the aggregates formed. This proves the vital role of agitation intensity on the morphological and physical properties of aggregates formed. The resultant aggregates formed by the IHDS process are very compact, dense and homogeneous in their size, shape, volume and inner structure. Last but not least, the IHDS process applied to the HR-CSAV type sludge blanket clarifier facilitated its high attainable upflow velocity above of 25 m h-1.
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Ginoyan, R. V., N. E. Nazarova, and Yu N. Bondareva. "The production technology of functional yoghurt, enriched with a mixture of dry wheat germ powder and bilberries and blueberries puree." Proceedings of the Voronezh State University of Engineering Technologies 80, no. 4 (March 21, 2019): 283–87. http://dx.doi.org/10.20914/2310-1202-2018-4-283-287.
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The use of dairy products and beverages containing substances useful for health is an effective means of strengthening the protective functions of the human body. The development of new products should be based on a reasonable selection of ingredients that form their composition and properties. One of the most relevant areas in the technology development of functional dairy products, including yogurt, is the identification and use of promising types of traditional plant crops and wild fruit and berry raw materials. The purpose of this work is to study the effect of different doses of a mixture of dry powder suspension of sprouted wheat, and mashed bilberries and blueberries on organoleptic characteristics, individual physical and chemical properties and safety of yogurt. The work is done in of the "Nizhny Novgorod State Agricultural Academy". While the research, a set of generally accepted standard research methods was used. Objects of research are samples of yogurt thermostatic with different doses of the components: 1.0; 1.5; 2.0; 2.5% of suspension of powder of sprouted wheat and 5.0; 7.0; 9.0; 11.0; 13.0% mashed bilberries and blueberries (1.5: 1.0). The fermentation was performed using dry starter cultures YO-MIX 495 LYO 100 DCU, Danisco Cultures. According to the results of a study designed and optimized component composition of yoghurt, selected dose, the stage and method of making milk of a mixture of additives, experimental studies on adjustment and sequence of technological modes of production of a particular group of samples of yoghurt. Optimal application dose of suspension of sprouted wheat powder in milk mixture amounted to 1.5%, puree of bilberries and blueberries(1.5:1.0) of 7.0%. In the obtained enriched sample the content of carbohydrates increases to 5.40–5.45%, the content of vitamin C-to 3.65-3.75 mg/%. Yogurt meets the requirements established CU TR 021/2011, CU TR 033/2013 and GOST 31981.
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LENSKY, N. G., V. LYAKHOVSKY, and O. NAVON. "Expansion dynamics of volatile-supersaturated liquids and bulk viscosity of bubbly magmas." Journal of Fluid Mechanics 460 (June 10, 2002): 39–56. http://dx.doi.org/10.1017/s0022112002008194.
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We derive expressions for the bulk viscosity of suspension of gas bubbles in an incompressible Newtonian liquid that exsolves volatiles. The suspension is modelled as close packed spherical cells and is represented by a single cell (‘cell model’). A cell, consisting of a gas bubble centred in a spherical shell of a volatile-bearing liquid, is subjected to decompression that is applied at the cell boundary, and the resulting dilatational boundary motion and driving pressure are obtained. The dilatational motion and the driving pressure are used to define the bulk viscosity of the cell, as if it were composed of a homogeneously compressible fluid. By definition, the bulk viscosity is the relation between changes of the driving pressure and changes in the resulting expansion strain rate. The bulk viscosity of the suspension is obtained in terms of two-phase parameters, i.e. bubble radius, gas pressure and the properties of the incompressible continuous liquid phase. The resulting bulk viscosity is highly nonlinear. At the beginning of the expansion process, when gas exsolution is efficient, the expansion rate grows exponentially while the driving pressure decreases slightly, which means that the bulk viscosity is formally negative. This negative value reflects the release of the energy stored in the supersaturated liquid and its transfer to mechanical work during exsolution. Later, when bubbles are large and the gas influx decreases significantly, the strain rate decelerates and the bulk viscosity becomes positive as expected in a dissipative system. We demonstrate that amplification of seismic waves travelling through a volcanic conduit filled with a volatile saturated magma may be attributed to the negative bulk viscosity of the compressible magma. Amplification of an expansion wave may, at some level in the conduit, damage the conduit walls and initiate the opening of a new pathway for magma eruption. We also consider the energy related to positive and negative bulk viscosities.
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Wang, Qian, Takashi Hisatomi, Masao Katayama, Tsuyoshi Takata, Tsutomu Minegishi, Akihiko Kudo, Taro Yamada, and Kazunari Domen. "Particulate photocatalyst sheets for Z-scheme water splitting: advantages over powder suspension and photoelectrochemical systems and future challenges." Faraday Discussions 197 (2017): 491–504. http://dx.doi.org/10.1039/c6fd00184j.
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Water splitting using semiconductor photocatalysts has been attracting growing interest as a means of solar energy based conversion of water to hydrogen, a clean and renewable fuel. Z-scheme photocatalytic water splitting based on the two-step excitation of an oxygen evolution photocatalyst (OEP) and a hydrogen evolution photocatalyst (HEP) is a promising approach toward the utilisation of visible light. In particular, a photocatalyst sheet system consisting of HEP and OEP particles embedded in a conductive layer has been recently proposed as a new means of obtaining efficient and scalable redox mediator-free Z-scheme solar water splitting. In this paper, we discuss the advantages and disadvantages of the photocatalyst sheet approach compared to conventional photocatalyst powder suspension and photoelectrochemical systems through an examination of the water splitting activity of Z-scheme systems based on SrTiO3:La,Rh as the HEP and BiVO4:Mo as the OEP. This photocatalyst sheet was found to split pure water much more efficiently than the powder suspension and photoelectrochemical systems, because the underlying metal layer efficiently transfers electrons from the OEP to the HEP. The photocatalyst sheet also outperformed a photoelectrochemical parallel cell during pure water splitting. The effects of H+/OH− concentration overpotentials and of the IR drop are reduced in the case of the photocatalyst sheet compared to photoelectrochemical systems, because the HEP and OEP are situated in close proximity to one another. Therefore, the photocatalyst sheet design is well-suited to efficient large-scale applications. Nevertheless, it is also noted that the photocatalytic activity of these sheets drops markedly with increasing background pressure because of reverse reactions involving molecular oxygen under illumination as well as delays in gas bubble desorption. It is shown that appropriate surface modifications allow the photocatalyst sheet to maintain its water splitting activity at elevated pressure. Accordingly, we conclude that the photocatalyst sheet system is a viable option for the realisation of efficient solar fuel production.