{"title":"An Experimental Investigation of the Cooling System for a Free Piston Stirling Engine","authors":"A. Gupte","doi":"10.33915/ETD.3706","DOIUrl":"https://doi.org/10.33915/ETD.3706","url":null,"abstract":"","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"49 1","pages":"36"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74444559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Scalability of Smoke Density and the Viability of New Detection Methods in Aircrafts","authors":"Selena K. Chin","doi":"10.13016/DSFP-D10N","DOIUrl":"https://doi.org/10.13016/DSFP-D10N","url":null,"abstract":"","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"18 1","pages":"53"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74493523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
NEW METHOD OF NICKEL OXIDE AS HOLE TRANSPORT LAYER AND CHARACTERISTICS OF NICKEL OXIDE BASED PEROVSKITE SOLAR CELL Loi Nguyen Old Dominion University, 2018 Director: Dr. Gon Namkoong For perovskite solar cells, poly (2,3-dihydrothieno-1, 4-dioxin)-poly (styrenesulfonate) (PEDOT:PSS) is a common hole transport layer. However, PEDOT:PSS has a lot of drawbacks, such as irregular quality from distributors, poor electron blocker, and hygroscopic nature. On the other hand, NiOx has been reported that it can provide good stability and carrier mobility. From literature, NiOx was used to replace PEDOT:PSS as a hole transport layer with positive results since it is transparent as a thin film and also possesses compatible work function in perovskite solar cell bandgap alignment. In depositing NiOx as a thin film, many approaches have been developed. However, those approaches required the use of acute toxic chemicals, lengthy processing time, complicated chemical requirement, and/ or expensive equipment. In order to obtain NiOx thin film as a hole transport layer, we have developed a facile method to obtain a thin film of NiOx by simply mixing NiOx powder and HCl solution. This process only needs less than 5 minutes of chemical mixing time and the precursor can be immediately spin-coated on top of substrate. In addition, the equipment needed to obtain thin film NiOx is a spin coater and a hot plate. With our quick, simple and inexpensive approach to get NiOx thin film for perovskite solar cells with inverted p-i-n structure, it is found that inverted perovskite solar cell with NiOx as a hole transport layer demonstrated higher open circuit voltage than perovskite solar cell fabricated with PEDOT:PSS, which enhanced solar cell power conversion efficiency. Our experiment has shown that NiOx thin film obtained by newly developed technique, exhibited promising material characteristics such as long lifetime decay. In our experiment, we also optimized the processing conditions of NiOx thin films to remove the light soaking effect caused by defects in NiOx layer. Hence, it is found that a quick, simple and inexpensive method enabled deposition of NiOx thin film as a promising hole transport layer for inverted p-i-n structure of perovskite solar cell.
氧化镍作为空穴传输层的新方法及镍基钙钛矿太阳能电池的特性Loi Nguyen Old Dominion University, 2018主任:Gon Namkoong博士对于钙钛矿太阳能电池，聚(2,3-二氢噻吩- 1,4 -二英)-聚(苯乙烯磺酸盐)(PEDOT:PSS)是一种常见的空穴传输层。然而，PEDOT:PSS有很多缺点，如经销商质量不稳定，电子阻隔性差，吸湿性差。另一方面，据报道，NiOx可以提供良好的稳定性和载流子迁移性。从文献来看，由于NiOx作为薄膜透明，并且在钙钛矿太阳能电池带隙对准中具有兼容的功功能，因此使用NiOx代替PEDOT:PSS作为空穴传输层取得了积极的结果。在沉积NiOx作为薄膜方面，已经开发了许多方法。然而，这些方法需要使用急性毒性化学品，处理时间长，化学品需求复杂，设备昂贵。为了获得作为空穴传输层的NiOx薄膜，我们开发了一种简单的方法，将NiOx粉末与HCl溶液混合即可获得NiOx薄膜。该过程只需要不到5分钟的化学混合时间，并且前驱体可以立即旋转涂覆在基材上。此外，获得薄膜NiOx所需的设备是旋转涂布机和热板。我们采用快速、简单、廉价的方法制备了用于倒p-i-n结构钙钛矿太阳能电池的NiOx薄膜，发现以NiOx为空穴传输层的倒钙钛矿太阳能电池比以PEDOT:PSS制备的钙钛矿太阳能电池具有更高的开路电压，提高了太阳能电池的功率转换效率。实验结果表明，新工艺制备的NiOx薄膜具有长寿命衰减等材料特性。在我们的实验中，我们还优化了NiOx薄膜的加工条件，以消除NiOx层中缺陷引起的光浸泡效应。因此，我们发现了一种快速、简单和廉价的方法，可以沉积NiOx薄膜，作为钙钛矿太阳能电池倒p-i-n结构的有前途的空穴传输层。
{"title":"New Method of Nickel Oxide as Hole Transport Layer and Characteristics of Nickel Oxide Based Perovskite Solar Cell","authors":"L. Nguyen","doi":"10.25776/8DX3-KZ45","DOIUrl":"https://doi.org/10.25776/8DX3-KZ45","url":null,"abstract":"NEW METHOD OF NICKEL OXIDE AS HOLE TRANSPORT LAYER AND CHARACTERISTICS OF NICKEL OXIDE BASED PEROVSKITE SOLAR CELL Loi Nguyen Old Dominion University, 2018 Director: Dr. Gon Namkoong For perovskite solar cells, poly (2,3-dihydrothieno-1, 4-dioxin)-poly (styrenesulfonate) (PEDOT:PSS) is a common hole transport layer. However, PEDOT:PSS has a lot of drawbacks, such as irregular quality from distributors, poor electron blocker, and hygroscopic nature. On the other hand, NiOx has been reported that it can provide good stability and carrier mobility. From literature, NiOx was used to replace PEDOT:PSS as a hole transport layer with positive results since it is transparent as a thin film and also possesses compatible work function in perovskite solar cell bandgap alignment. In depositing NiOx as a thin film, many approaches have been developed. However, those approaches required the use of acute toxic chemicals, lengthy processing time, complicated chemical requirement, and/ or expensive equipment. In order to obtain NiOx thin film as a hole transport layer, we have developed a facile method to obtain a thin film of NiOx by simply mixing NiOx powder and HCl solution. This process only needs less than 5 minutes of chemical mixing time and the precursor can be immediately spin-coated on top of substrate. In addition, the equipment needed to obtain thin film NiOx is a spin coater and a hot plate. With our quick, simple and inexpensive approach to get NiOx thin film for perovskite solar cells with inverted p-i-n structure, it is found that inverted perovskite solar cell with NiOx as a hole transport layer demonstrated higher open circuit voltage than perovskite solar cell fabricated with PEDOT:PSS, which enhanced solar cell power conversion efficiency. Our experiment has shown that NiOx thin film obtained by newly developed technique, exhibited promising material characteristics such as long lifetime decay. In our experiment, we also optimized the processing conditions of NiOx thin films to remove the light soaking effect caused by defects in NiOx layer. Hence, it is found that a quick, simple and inexpensive method enabled deposition of NiOx thin film as a promising hole transport layer for inverted p-i-n structure of perovskite solar cell.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"8 1","pages":"7"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91244730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-01DOI: 10.31274/etd-180810-6123
Zihao Xu
Gellan gum is a naturally occurring polymer that can crosslink in the presence of divalent cations to form biocompatible hydrogels. However, physically crosslinked gellan gum hydrogels lose stability under physiological conditions, which substantially limits the applications of these hydrogels in vivo. In order to improve the mechanical strength, we incorporated methacrylate into gellan gum and chemically crosslinked the hydrogel through three polymerization methods: step growth through thiol-ene photoclick chemistry, chain growth via photopolymerization, and mixed model in which both mechanisms were employed. Methacrylation was confirmed and quantified by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FTIR). The mechanical property and chemistry of the crosslinked gels were systematically explored by varying the reaction conditions. The swelling ratios of the hydrogels were correlated with the compression moduli and affected by the addition of calcium. In vitro enzymatic degradation rate was found dependent on the degree of methacrylation. NIH/3T3 fibroblast cell proliferation and morphology were related to substrate stiffness with high stiffness leading generally to higher proliferation. The proliferation is further affected by the thiol-ene ratios. We then further modified methacrylate Gellan gum with alkane bromide to increase hydrophobicity. Cell attachment on resultant hydrogels were assessed and imaged. Cytokine release was also measured with comparison to pristine methacrylated Gellan gum based hydrogels. The results suggest that a hydrogel platform based on gellan gum can offer versatile chemical modifications and tunable mechanical properties for a variety of biomaterials applications, such as the wound healing scaffold.
{"title":"Gellan gum based thiol-ene hydrogels with tunable properties for use as tissue engineering scaffolds","authors":"Zihao Xu","doi":"10.31274/etd-180810-6123","DOIUrl":"https://doi.org/10.31274/etd-180810-6123","url":null,"abstract":"Gellan gum is a naturally occurring polymer that can crosslink in the presence of divalent cations to form biocompatible hydrogels. However, physically crosslinked gellan gum hydrogels lose stability under physiological conditions, which substantially limits the applications of these hydrogels in vivo. In order to improve the mechanical strength, we incorporated methacrylate into gellan gum and chemically crosslinked the hydrogel through three polymerization methods: step growth through thiol-ene photoclick chemistry, chain growth via photopolymerization, and mixed model in which both mechanisms were employed. Methacrylation was confirmed and quantified by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FTIR). The mechanical property and chemistry of the crosslinked gels were systematically explored by varying the reaction conditions. The swelling ratios of the hydrogels were correlated with the compression moduli and affected by the addition of calcium. In vitro enzymatic degradation rate was found dependent on the degree of methacrylation. NIH/3T3 fibroblast cell proliferation and morphology were related to substrate stiffness with high stiffness leading generally to higher proliferation. The proliferation is further affected by the thiol-ene ratios. We then further modified methacrylate Gellan gum with alkane bromide to increase hydrophobicity. Cell attachment on resultant hydrogels were assessed and imaged. Cytokine release was also measured with comparison to pristine methacrylated Gellan gum based hydrogels. The results suggest that a hydrogel platform based on gellan gum can offer versatile chemical modifications and tunable mechanical properties for a variety of biomaterials applications, such as the wound healing scaffold.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"88 6 1","pages":"2"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84056257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A COST EFFECTIVE DESIGN FOR A PROPELLER THRUST/TORQUE BALANCE Nicholas Barrett Sadowski Old Dominion University, 2018 Director: Dr. Drew Landman Wind tunnel balances are used with aircraft models, propellers, and components to measure applied forces and moments. The design and manufacture of a balance is often for a specific test, test article and conditions. This paper discusses the theory, design, calibration, and testing of a new small propeller balance for use in a low-speed wind tunnel. The new balance is named the ODU15X15. Theory discussed herein covers how the two measurement components, thrust and torque, affect the balance design. These loads generate strains which are in turn read by strain gages arranged in Wheatstone bridges. The design follows well known practices established at NASA Langley for single-piece balances. Design considerations include constraints on geometry shape/size, thermal compensation, vibration inputs, balance sensitivity requirements, and safety. Analysis of the balance is performed using solid computer aided design models and iterative finite element analysis. Goals for this design were to create a cost effective balance, made using only conventional machining, made out of a single billet or section of tubing, and to create a balance capable of measuring loads more accurately then those commercially available for the relatively low loads predicted. The ODU15X15 is designed to read 15 lbs thrust and 15 in-lbs torque. Calibration, including theory, set-up, design, and procedures, follows the principles of Design of Experiments. A LabView code is used to record voltage outputs from Wheatstone bridges with known loads applied to the balance. Fixtures are used to apply the static thrust and torque loads. Calibration of the balance resulted in less than ±0.1% full-scale error at a ninety five percent confidence level. Confirmation points provided additional assurance of model adequacy. Wind tunnel trials were performed with a Scorpion SII-4020-420kv motor, and a 3 blade 16 X 8 Master Airscrew propeller at conditions representative of previous testing with NASA GL-10 propeller candidates. While further testing is needed, results indicate that the balance performance was superior to the commercial load cell.
Nicholas Barrett Sadowski Old Dominion University, 2018主任:Dr. Drew Landman风洞平衡器用于飞机模型、螺旋桨和部件来测量施加的力和力矩。天平的设计和制造往往是针对特定的试验、试验物品和条件而进行的。本文讨论了一种用于低速风洞的新型小型螺旋桨平衡的原理、设计、标定和试验。新的天平被命名为ODU15X15。本文讨论的理论涵盖了推力和扭矩这两个测量分量如何影响平衡设计。这些荷载产生的应变依次由布置在惠斯通桥上的应变计读取。设计遵循了美国宇航局兰利单件平衡的众所周知的做法。设计考虑因素包括几何形状/尺寸的限制、热补偿、振动输入、平衡灵敏度要求和安全性。利用实体计算机辅助设计模型和迭代有限元分析进行了平衡分析。该设计的目标是创造一种具有成本效益的天平，仅使用传统加工，由单个钢坯或一段油管制成，并创造一种能够更准确地测量负载的天平，而不是那些商业上可用于预测相对较低负载的天平。ODU15X15设计用于读取15磅的推力和15磅的扭矩。校准，包括理论，设置，设计和程序，遵循实验设计的原则。LabView代码用于记录Wheatstone电桥在已知负载下的电压输出。固定装置用于施加静态推力和扭矩负载。在95%的置信水平上校准天平的结果小于±0.1%的满量程误差。确认点提供了模型充分性的额外保证。风洞试验采用了Scorpion SII-4020-420kv电机和一个3叶片16 X 8 Master Airscrew螺旋桨，试验条件代表了之前NASA GL-10候选螺旋桨的测试。虽然需要进一步的测试，但结果表明，平衡性能优于商用称重传感器。
{"title":"A Cost Effective Design for a Propeller Thrust/Torque Balance","authors":"N. Sadowski","doi":"10.25777/F8MC-9C26","DOIUrl":"https://doi.org/10.25777/F8MC-9C26","url":null,"abstract":"A COST EFFECTIVE DESIGN FOR A PROPELLER THRUST/TORQUE BALANCE Nicholas Barrett Sadowski Old Dominion University, 2018 Director: Dr. Drew Landman Wind tunnel balances are used with aircraft models, propellers, and components to measure applied forces and moments. The design and manufacture of a balance is often for a specific test, test article and conditions. This paper discusses the theory, design, calibration, and testing of a new small propeller balance for use in a low-speed wind tunnel. The new balance is named the ODU15X15. Theory discussed herein covers how the two measurement components, thrust and torque, affect the balance design. These loads generate strains which are in turn read by strain gages arranged in Wheatstone bridges. The design follows well known practices established at NASA Langley for single-piece balances. Design considerations include constraints on geometry shape/size, thermal compensation, vibration inputs, balance sensitivity requirements, and safety. Analysis of the balance is performed using solid computer aided design models and iterative finite element analysis. Goals for this design were to create a cost effective balance, made using only conventional machining, made out of a single billet or section of tubing, and to create a balance capable of measuring loads more accurately then those commercially available for the relatively low loads predicted. The ODU15X15 is designed to read 15 lbs thrust and 15 in-lbs torque. Calibration, including theory, set-up, design, and procedures, follows the principles of Design of Experiments. A LabView code is used to record voltage outputs from Wheatstone bridges with known loads applied to the balance. Fixtures are used to apply the static thrust and torque loads. Calibration of the balance resulted in less than ±0.1% full-scale error at a ninety five percent confidence level. Confirmation points provided additional assurance of model adequacy. Wind tunnel trials were performed with a Scorpion SII-4020-420kv motor, and a 3 blade 16 X 8 Master Airscrew propeller at conditions representative of previous testing with NASA GL-10 propeller candidates. While further testing is needed, results indicate that the balance performance was superior to the commercial load cell.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"212 0 1","pages":"26"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77089191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-01-01DOI: 10.31274/ETD-180810-5937
T. Ales
A complete model for the prediction of the yield strength of Titanium 6Al-4V in an additively manufactured component is presented herein. A thermal model is presented utilizing the ABAQUS simulation software to provide the process leg of the materials tetrahedron. The thermal model is fed into an implementation of the Langmuir equation that has been adapted for use in the simulation of the Electron-Beam Additive Manufacturing (EBAM) process. The predicted chemistry provided by the Langmuir equation for the Ti-6Al-4V alloy is then used in a phenomenological equation for the prediction of yield strength; a design probability curve is generated through random sampling of the thermal model. Using Weibull probability distributions, the model is verified against a rich mechanical and chemical database built from an actual EBAM build used in previous research.
{"title":"An Integrated Model for the Probabilistic Prediction of Yield Strength in Electron-Beam Additively Manufactured Ti-6Al-4V","authors":"T. Ales","doi":"10.31274/ETD-180810-5937","DOIUrl":"https://doi.org/10.31274/ETD-180810-5937","url":null,"abstract":"A complete model for the prediction of the yield strength of Titanium 6Al-4V in an additively manufactured component is presented herein. A thermal model is presented utilizing the ABAQUS simulation software to provide the process leg of the materials tetrahedron. The thermal model is fed into an implementation of the Langmuir equation that has been adapted for use in the simulation of the Electron-Beam Additive Manufacturing (EBAM) process. The predicted chemistry provided by the Langmuir equation for the Ti-6Al-4V alloy is then used in a phenomenological equation for the prediction of yield strength; a design probability curve is generated through random sampling of the thermal model. Using Weibull probability distributions, the model is verified against a rich mechanical and chemical database built from an actual EBAM build used in previous research.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"13 1","pages":"15"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88448189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Effect of FORTA-FI Fibers on the Rutting Potential, Dynamic Modulus, Flow Number, and Fatigue of Asphalt Concrete Elbert Rohrbough The effect of fiberreinforcement on asphalt concrete mixes is better explored through laboratory performance testing. Two mixes were evaluated throughout this research. One mix was a standard West Virginia Department of Highways Wearing I, and the other was the Wearing I mix reinforced with FORTAFI® fibers. The testing was done using the Asphalt Pavement Analyzer (APA) and the Asphalt Mixture Performance Tester (AMPT). First, the rutting potential of the two mixes was determined using the APA. Next, the performance of the two mixes was compared using the AMPT. The tests performed on the AMPT determined the dynamic modulus, flow number, and fatigue characteristics of the two mixes. Dynamic modulus master curves were developed using Bonaquist’s MasterSolver Version 2.2 to compare the stiffness of the two mixes. The flow number was evaluated using the Data Smoothing Method and the Francken Model Method to compare the rutting potential of the two mixes. Last, Instrotek’s Alpha-FatigueTM software was used to determine the coefficients needed to model the fatigue behavior of the mixes.
{"title":"Effect of FORTA-FI Fibers on the Rutting Potential, Dynamic Modulus, Flow Number, and Fatigue of Asphalt Concrete","authors":"Elbert Rohrbough","doi":"10.33915/etd.6524","DOIUrl":"https://doi.org/10.33915/etd.6524","url":null,"abstract":"Effect of FORTA-FI Fibers on the Rutting Potential, Dynamic Modulus, Flow Number, and Fatigue of Asphalt Concrete Elbert Rohrbough The effect of fiberreinforcement on asphalt concrete mixes is better explored through laboratory performance testing. Two mixes were evaluated throughout this research. One mix was a standard West Virginia Department of Highways Wearing I, and the other was the Wearing I mix reinforced with FORTAFI® fibers. The testing was done using the Asphalt Pavement Analyzer (APA) and the Asphalt Mixture Performance Tester (AMPT). First, the rutting potential of the two mixes was determined using the APA. Next, the performance of the two mixes was compared using the AMPT. The tests performed on the AMPT determined the dynamic modulus, flow number, and fatigue characteristics of the two mixes. Dynamic modulus master curves were developed using Bonaquist’s MasterSolver Version 2.2 to compare the stiffness of the two mixes. The flow number was evaluated using the Data Smoothing Method and the Francken Model Method to compare the rutting potential of the two mixes. Last, Instrotek’s Alpha-FatigueTM software was used to determine the coefficients needed to model the fatigue behavior of the mixes.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"118 1","pages":"6"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75775027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
UAV Modeling and Simulation at Normal and Abnormal Conditions Mofetoluwa Fagbemi The main objective of this thesis is to develop new capabilities within the West Virginia University (WVU) unmanned aerial systems (UAS) simulation environment for the design and analysis of fault tolerant control laws on small sized unmanned aerial vehicles (UAVs). An aerodynamic model for an electric powered UAV is developed using a vortex lattice method implemented within the computational design package Tornado. One-dimensional look-up tables are developed for the main stability and control derivatives, which are then used to calculate linear aerodynamic forces and moments for the nonlinear aircraft equations of motion. Flight data are used for model verification and tuning. The characteristics under normal and abnormal operation of various types of sensors typically used for UAV control are classified under nine functional categories. A general and comprehensive framework for sensor modeling is defined as a sequential alteration of the exact value of the measurand corresponding to each functional category. Simple mathematical and logical algorithms are formulated and used in this process. Each functional category is characterized by several parameters, which may be maintained constant or may vary during simulation. The user has maximum flexibility in selecting values for the parameters within and outside sensor design ranges. These values can be set to change at pre-defined moments, such that permanent and intermittent scenarios can be simulated. The aircraft and sensor models are then integrated with the WVU UAS simulation environment, which is created using MATLAB/Simulink for the computational part and FlightGear for the visualization of the aircraft and scenery. A simple user-friendly graphical interface is designed to allow for detailed simulation scenario setup. The functionality of the developed models is illustrated through a limited analysis of the effects of sensor abnormal operation on the trajectory tracking performance of autonomous UAV. A composite metric is used for aircraft performance assessment based on both trajectory tracking errors and control activity. The targeted sensors are the gyroscopes providing angular rate measurements and the global positioning system providing position and velocity information. These sensors are instrumental in the inner and outer control loops, respectively, which characterize the typical control architecture for autonomous trajectory tracking. Due to its generality and flexibility, the proposed sensor model provides detailed insight into the dynamic implications of sensor functionality on the performance of control algorithms. It facilitates the investigation of the synergistic interactions between sensors and control systems and may lead to improvements in both areas.
{"title":"UAV Modeling and Simulation at Normal and Abnormal Conditions","authors":"M. Fagbemi","doi":"10.33915/etd.5564","DOIUrl":"https://doi.org/10.33915/etd.5564","url":null,"abstract":"UAV Modeling and Simulation at Normal and Abnormal Conditions Mofetoluwa Fagbemi The main objective of this thesis is to develop new capabilities within the West Virginia University (WVU) unmanned aerial systems (UAS) simulation environment for the design and analysis of fault tolerant control laws on small sized unmanned aerial vehicles (UAVs). An aerodynamic model for an electric powered UAV is developed using a vortex lattice method implemented within the computational design package Tornado. One-dimensional look-up tables are developed for the main stability and control derivatives, which are then used to calculate linear aerodynamic forces and moments for the nonlinear aircraft equations of motion. Flight data are used for model verification and tuning. The characteristics under normal and abnormal operation of various types of sensors typically used for UAV control are classified under nine functional categories. A general and comprehensive framework for sensor modeling is defined as a sequential alteration of the exact value of the measurand corresponding to each functional category. Simple mathematical and logical algorithms are formulated and used in this process. Each functional category is characterized by several parameters, which may be maintained constant or may vary during simulation. The user has maximum flexibility in selecting values for the parameters within and outside sensor design ranges. These values can be set to change at pre-defined moments, such that permanent and intermittent scenarios can be simulated. The aircraft and sensor models are then integrated with the WVU UAS simulation environment, which is created using MATLAB/Simulink for the computational part and FlightGear for the visualization of the aircraft and scenery. A simple user-friendly graphical interface is designed to allow for detailed simulation scenario setup. The functionality of the developed models is illustrated through a limited analysis of the effects of sensor abnormal operation on the trajectory tracking performance of autonomous UAV. A composite metric is used for aircraft performance assessment based on both trajectory tracking errors and control activity. The targeted sensors are the gyroscopes providing angular rate measurements and the global positioning system providing position and velocity information. These sensors are instrumental in the inner and outer control loops, respectively, which characterize the typical control architecture for autonomous trajectory tracking. Due to its generality and flexibility, the proposed sensor model provides detailed insight into the dynamic implications of sensor functionality on the performance of control algorithms. It facilitates the investigation of the synergistic interactions between sensors and control systems and may lead to improvements in both areas.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"74 1","pages":"6"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85954762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Modular Multi-Level Converter for Energy Management of Hybrid Energy-Storage Systems in Electric Vehicles","authors":"Sharon George","doi":"10.31979/etd.94h5-2h6q","DOIUrl":"https://doi.org/10.31979/etd.94h5-2h6q","url":null,"abstract":"","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"21 1","pages":"30"},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73376012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Design of compliant mechanism lattice structures for impact energy absorption","authors":"Joel C. Najmon","doi":"10.7912/C2NQ1Z","DOIUrl":"https://doi.org/10.7912/C2NQ1Z","url":null,"abstract":"","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"5 1","pages":"31"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82562400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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