Theory of Computing Systems \/ Mathematical Systems Theory最新文献

{"title":"Systems Modeling and Techno-economic Analysis for reACT Net-zero Energy Home","authors":"Akanksha Bhat","doi":"10.13016/qyli-wf1t","DOIUrl":"https://doi.org/10.13016/qyli-wf1t","url":null,"abstract":"","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"19 1","pages":"20"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85800397","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":"Development of Ni-based Oxide Dispersion Strengthened (ODS) Powder Particles for Metal Additive Manufacturing (AM) Applications","authors":"M. McPherson","doi":"10.33915/ETD.4027","DOIUrl":"https://doi.org/10.33915/ETD.4027","url":null,"abstract":"Development of Ni-based Oxide Dispersion Strengthened (ODS) powder for Metal Additive Manufacturing (AM) Applications Markova Dion McPherson The capabilities of Additive Manufacturing (AM) techniques have grown rapidly in recent years, however, current available metal powders for AM processes, such as Powder Bed Fusion and Directed Energy Deposition, are limited and primarily fabricated through gas atomization process which; the gas atomization process is capable of producing metal powders 15 μm to 150 μm in size with near spherical shape. Despite the advantages of atomization process, iron or nickel-based Oxide Dispersion Strengthened (ODS) powders, with nanocrystalline microstructure, cannot be produced with the gas atomization process because of the high melting temperature of yttrium (III) oxide (Y2O3, 2425 °C) compared to iron (Fe, 1538 °C), nickel (Ni, 1668 °C), chromium (Cr, 1907 °C) and aluminum (Al, 660 °C), thus, uniform dispersion of Y2O3 is problematic for ODS powders. In this work, a combination of Mechano-Chemical Bonding (MCB) process and Mechanical Alloying (MA) by planetary ball milling (BM) will be implemented to produce ODS powders suitable for AM applications. The MCB process fractures and uniformly disperse the Y2O3 nanoparticles and the nanoparticles are bonded on the surface of the master particles (Ni and Cr). Also, the MA process, because of the constant fracturing and cold-welding of the elemental particles, produces alloyed ODS powders with suitable uniform size distribution, near spherical shape, and nanocrystalline microstructure. The objectives of this research are to (1) optimize the MCB+BM processing parameters and (2) study effects of the process parameters on the size, morphology, and microstructure of Ni-based ODS powders for metal AM applications using Laser Engineering Net Shaping (LENS) machine. Results showed that Ni-based ODS particles with nearly spherical in morphology, average particle size of 15 μm, uniform dispersion of Y2O3, and nanocrystalline microstructure can be successfully produced via the proposed MCB + BM methodology. These resultant Ni-based ODS particles were successfully used on a LENS AM machine to produce coupon specimen. The coupon specimen microstructure contains γ-NiAl matrix and submicron γ’-Ni3Al strengthening phase.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"1 1","pages":"70"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80737036","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 Effect of Porosity on Mechanical Properties of Fused Deposition Manufactured Polymers and Composites","authors":"E. Anderson","doi":"10.31979/etd.rkaj-q4tv","DOIUrl":"https://doi.org/10.31979/etd.rkaj-q4tv","url":null,"abstract":"Additive manufacturing has seen sustained growth in both consumer and industrial areas. fused deposition manufacturing (FDM), a specific additive manufacturing technology, has seen increased sales in consumer markets. In order to maintain growth, FDM will be increasingly used for load-bearing applications. However, the mechanical reliability of FDM polymers and composites is not well understood. This can be dangerous to property and safety. Presented in this paper are more than 16 distinct populations comprised of at least 23 unique tensile tests, a total of 506 tensile tests. Weibull statistics were used to quantify variance in physical properties of FDMed materials. It is the hope of the author that these data will provide essential information for designers to make parameter selections for safe load-bearing applications of FDM parts. Using the deviations from Weibull, scanning electron microscopy, and micro X-ray CT, the author examined the origins of variations in mechanical properties. A key factor in mechanical reliability comprises variations in the size and shape of inter-bead pores. In the final section, this problem was addressed with a novel vibration assisted FDM (VA-FDM) that reduced the porosity by 3 %, increased the fracture strength by 12 %, and doubled the tensile strength reliability. These findings showed that inter-bead porosity can be significantly reduced by localized extruder vibrations and that reduced inter-bead porosity influences the mechanical properties and variations in those properties.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"18 1","pages":"27"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89088296","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":"Investigating Microalloying Elements to Accelerate Zirconium Trialuminide Precipitation in Aluminum Alloys","authors":"P. Staublin","doi":"10.37099/mtu.dc.etdr/914","DOIUrl":"https://doi.org/10.37099/mtu.dc.etdr/914","url":null,"abstract":". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"74 1","pages":"81"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75078872","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":"Comparison of Support Methods for Static Aerodynamic Testing and Validation of a Magnetic Suspension and Balance System","authors":"Cameron Neill","doi":"10.25777/24MK-BN25","DOIUrl":"https://doi.org/10.25777/24MK-BN25","url":null,"abstract":"COMPARISON OF SUPPORT METHODS FOR STATIC AERODYNAMIC TESTING AND VALIDATION OF MAGNETIC SUSPENSION AND BALANCE SYSTEM Cameron K. Neill Old Dominion University, 2019 Director: Dr. Colin Britcher Magnetic suspension wind tunnels offer an alternative to traditional physical support methods. They allow for the collection of support interference free data and broader dynamic test capabilities than existing methods. Determination of dynamic aerodynamic characteristics is a crucial portion of the design of new re-entry capsules. A NASA initiative restored the 6-inch Magnetic Suspension and Balance System to support the design of a new MSBS for a supersonic wind tunnel. Before a new MSBS can be constructed, the characteristics of the current MSBS must be examined. This thesis discusses the calibration and validation of the 6-inch MSBS. After calibration, three aerodynamic tests were performed in order to characterize the data collected from the MSBS. They included a traditional sting supported test, a free-flying magnetically suspended test, and a magnetically suspended test with aerodynamic interference from a dummy sting. The ideology behind the chosen experimental design was to isolate the effect of support interference from any MSBS calibration errors. Any differences between the sting supported and the dummy sting tests would be caused by the MSBS. Any differences between the free-flying and the dummy sting tests would be due to support interference. Multiple components were designed and constructed, in order to support this effort. The goals of this thesis were met. The MSBS data had high repeatability and accuracy, which validated the force recovery method. Aerodynamic testing showed in minimal variation between support methods at low angles of attack. Discrepancies between support methods increased with models mounted at high angles of attack. Current references generally exhibit much higher Reynolds numbers than the MSBS and the wind tunnel can achieve. Support interference free reference data in an achievable Reynolds number was generated for future NASA testing. While the outcome was successful, multiple possible improvements or future projects were identified that can be completed prior to design and construction of the new MSBS.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"25 ","pages":"8"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91465135","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":"Chitosan-Coated Cerium Oxide Nanoparticles and Sparfloxacin Encapsulated Polymersomes as a New Drug System with Antimicrobial Properties","authors":"Siqi Zhao","doi":"10.17760/d20292602","DOIUrl":"https://doi.org/10.17760/d20292602","url":null,"abstract":"Bacterial infections are a common problem worldwide. In the 20 century, because of the discovery of penicillin, for the first time, people had an effective way to fight bacterial infections. However, with the abuse of antibiotics, many bacteria are developing a resistance to such drugs. Now, bacteria can survive an antibiotic attack, making them more dangerous and potentially fatal to the patient. Nanoparticles have aroused interest as a new antimicrobial treatment due to their excellent ability to kill bacteria. Moreover, bacteria are less likely to develop resistance against nanoparticles because nanoparticles use a variety of different mechanisms to kill bacteria such as increased reactive oxygen species generation, blocking of membrane pores, etc. Herein, we synthesized novel cerium oxide nanoparticles (CeNPs) and tested their antibacterial properties due to their ability to change oxidative state with pH changes. Results showed that they are effective against Gram-positive bacteria like Staphylococcus epidermidis at 250 μg/ml. In contrast, cytotoxicity tests indicated that CeNPs are not toxic to human dermal fibroblasts (HDF) when the concentration is below 500 μg/ml. However, the problem with CeNPs is their tendency to agglomerate because of their tiny size and high surface energy, which reduces their efficiency. Therefore, we added chitosan to the CeNP suspension to provide a coating that reduces agglomeration. The chitosan-coated CeNPs (C-CeNPs) were better dispersed in water, and they showed better antimicrobial properties than CeNPs alone. Furthermore, we also used polymersomes as a novel nanocarrier for C-CeNPs and drugs which can help control drug release in the human body. After encapsulating CCeNPs and sparfloxacin (an antibiotic) together into polymersomes, this new drug system showed better antibacterial properties than just the drug itself, which indicates such nanodevices should be studied for a wide range of antibacterial applications.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"1 1","pages":"8"},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90397532","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":"Estimating and mapping chlorophyll-a concentration in Boston Harbor, MA using LandSat data","authors":"Q. Cao","doi":"10.17760/d20291450","DOIUrl":"https://doi.org/10.17760/d20291450","url":null,"abstract":"","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"1 1","pages":"25"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88144440","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":"Coax-Fed Dipole-Type Applicator for Hepatic Cancer RF Ablation","authors":"Basari Basari, Aditya Rakhmadi, K. Saito","doi":"10.7454/MST.V22I1.3382","DOIUrl":"https://doi.org/10.7454/MST.V22I1.3382","url":null,"abstract":"Cancer is the third leading cause of mortality in t he world and is one of the most difficult diseases to detect and cure. This fact motivates us to investigate a treatment m e hod by using radiofrequency (RF) ablation. RF abl ation therapy kills cancer cells by electromagnetically heating t hem up. The treatment uses an applicator that is in serted into the body to heat the cells. The cancer cells are exposed to a temperature of more than 60 °C in short duration (a few seconds to a few minutes), thereby causing cell destruction loca lly. To ensure effective treatment, a minimally inv asive method is selected so that good local temperature distributio n inside the cancer cells can be achieved. In this paper, a coax-fed dipole-type applicator is proposed for interstitial irradiation technique in hepatic cell treatment. The applicator design is conducted by simulation in CST Microwave Studio to obtain an appropriate size at operating frequency o f 2.45 GHz. We also consider localizing the ablation area by de signing the tip of the applicator such that the mai n electromagnetic radiation locally exists around it. The proposed ap plicator is inserted into a simple phantom model of an adult human body with normal and cancerous liver cells. Both si mulation and measured results show that the propose d applicator is able to operate at center frequency of 2.45 GHz in a blood droplet-type ablation zone. A temperature o f 60 °C around the cancer cell can be achieved by simulation. More over, a square four-array applicator is analyzed to increase the ablation zone for a larger tumor cell. The simulation results show that a reasonably wider local ablation area can be achieved.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"10 3 1","pages":"46-52"},"PeriodicalIF":0.0,"publicationDate":"2018-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78044850","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":"Investigation of the Stiffness and Strength of Particulate Composites by Means of a Variant Cubic Model and SEM Fractography Microscopic Approach","authors":"E. Sideridis, V. Kytopoulos, Antonis Kampouroglou, J. Venetis","doi":"10.13189/MST.2018.050101","DOIUrl":"https://doi.org/10.13189/MST.2018.050101","url":null,"abstract":"In this article the stiffness of particulate composites is determined by the use of a multivariant three-phase model. This model consists of the transformation of spatial cubic models; it simulates a particulate composite into a three-sphere model, designating the two main phases of the composite material, the filler and the matrix, and applying the classical theory of elasticity to it. Theoretical results derived from this model are compared with experimental results derived from tensile tests carried out with iron particle reinforced epoxy resin composites and also with other theoretical results given by other researchers. In this context, an attempt is made to give, in a somewhat tentative way, a semiquantitative explanation of certain discrepancies observed between experimental data and the theory concerning the elastic modulus as well as experimental data concerning some fracture parameters on the basis of a macroscopic and a fractography-aided microscopic approach.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"1 1","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"2018-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83409227","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":"Seismic Response Analysis along the Coastal Area of Bengkulu during the September 2007 Earthquake","authors":"L. Z. Mase","doi":"10.7454/MST.V22I1.3457","DOIUrl":"https://doi.org/10.7454/MST.V22I1.3457","url":null,"abstract":"A strong earthquake of 8.4 M w occurred at the Sumatra Subduction Zone in Septemb er 12, 2007. The area that underwent the impact of the earthquake was located long the coastal area of the Bengkulu Province. A seismic ground response study was then performed with reference to the event. Several site investigations, including standard penetration test and shear wave velocity tests, wer e conducted to understand the subsoil condition. Th e data were used to analyze a ground response during the earthquake. Th amplification factor of each site was obtained , and a comparison of the spectral accelerations was perfor med. The results showed that the study area could u ndergo an amplification factor ranging from 1.1 to 1.5 during the seismic wave propagation. The spectral acceler ation that resulted from the seismic response analysis was also within the design value. The study results could generally bring awareness to local engineers to consider the seismic design v alue for the coastal area of the Bengkulu Province, particularly if a stronger earthquake happens in the future.","PeriodicalId":22842,"journal":{"name":"Theory of Computing Systems \\/ Mathematical Systems Theory","volume":"17 1","pages":"37-45"},"PeriodicalIF":0.0,"publicationDate":"2018-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89355860","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}