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Design Of Plantwide Control Structure Of A Small-Scale Concentrated Solar Power Process Cooperated With Organic Rankine Cycle And Thermal Storage Systems, Pathawut Bua-Ngam

Chulalongkorn University Theses and Dissertations (Chula ETD)

This work presents a study on control system design of a small-scale electricity generation process for household applications using plantwide control technique. The process are of three sections including parabolic trough solar collector, thermal energy storage, and organic Rankine cycle system. Synthetic oil Dowtherm©A and acetone were chosen as heat transfer fluid and working fluid, respectively. In terms of control objectives, the control structure can keep the process operation at maximum efficiency and response the required work load. Control performance of the control structure proposed is tested under various disturbance changes by using dynamic simulator (SIMSCI DYNSIM). The scenarios investigated …

Effect Of Particle Size Of Silica And Sio2/Mao Ratios On Heterogeneous Metallocene Catalyst Performance And Polyethylene Properties, Chalermpong Ramrauytham

Chulalongkorn University Theses and Dissertations (Chula ETD)

The metallocene catalyst is one of the catalysts, used to produce polyethylene having narrow molecular weight distribution. So, the metallocene catalyst has been interesting in many researches. To activate metallocene catalyst in ethylene polymerization, methylaluminoxane has been used as cocatalyst because it makes high activity for metallocene catalyst. However, both of them are in solution form, which make fouling in reactor and not good morphology in slurry ethylene polymerization. This problem has been solved by heterogeneous metallocene catalyst. Silica is widely used for heterogeneous metallocene catalyst because of high surface area and good morphology. This research is aimed to study …

Propane Dehydrogenation To Olefins Via Modified Pt-Based/Γ-Al2o3, Napat Hataivichian

Chulalongkorn University Theses and Dissertations (Chula ETD)

The effect of transition metal(X) added on Pt/Al2O3 catalyst was studied in propane dehydrogenation reaction at 500oC. The metal contents were fixed at 0.3%wt for Pt, 4%wt for X. It was found that the transition metal had an effect upon reducibility of platinum due to its interaction with X-containing structure, resulting in the presence of Pt metal was decreased and lower initial conversions are observed. However, the final conversions are not decreased, thus the bimetallic catalysts had a better stability because the transition metal sites attracted propylene from Pt sites, so there is no propylene remain adsorbed on Pt site, …

Effect Of Modified Tungsten Based Metathesis Catalysts By Ion Exchange Method With Alkali Metal Group 1a Solutions, Kritsada Pipitthapan

Chulalongkorn University Theses and Dissertations (Chula ETD)

The effect of sodium hydroxide and potassium hydroxide solutions in ion exchange with the WO3/SiO2 catalysts was investigated in the metathesis of trans-2-butene and ethylene for propylene production. The concentrations of alkali solutions used ion exchange were vaired from 0 to 6.75 mmol/L. The results suggested that the active center precursors of the metathesis were diminished at high concentrations of alkali solutions (>2.25 mmol/L). On the other hand at the low concentrations (

Impact Of Hydrotalcite Co-Catalyst On Metathesis Of Ethylene And2-Butene Over Silica-Zeolite Supported Tungsten Catalysts, Kriangkrai Aranyarat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Silica-zeolite supported tungsten oxide catalysts were physically mixed with hydrotalcite synthesized by co-precipitation method and investigated in the metathesis reaction of ethylene and trans-2-butene for propylene production. In this work, the effects of transition metal (a, b, c) doping on the hydrotalcite catalysts and N2-pretreatment on the catalytic properties of hydrotalcite mixed WO3-based catalysts were studied. The use of b-doped hydrotalcite with b/Mg-Al ratio 0.18 mixed with the WO3-based catalysts was found to increase the metathesis activity due to the higher amount of tungsten active species formed on the WO3-based catalysts and the higher isomerization activity of the b-doped hydrotalcite. …

A Production Planning System For A Lubricating Oil Production Company, Panisorn Saerevatanawoot

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objective of this research is to develop a production planning system for a lubricating oil company. The company is facing a problem of excessive inventory of finished goods and packaging materials resulting from the minimum stock levels that were established by its customer. The scope of the system covers class A products, consisting of 14 of 45 products in the company, and their packaging materials. The causes of the inventory problem were brainstormed with the use of Cause-and-Effect Diagram, then the Cause-and-Effect Matrix was used to identify potential root causes. It was concluded that master production schedule (MPS) of …

Scheduling In A Textile Dyeing Factory, Nattakarn Uttamapinant

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objective of this research is to develop a scheduling system for a textile dyeing factory in order to reduce production lead time and late deliveries. The factory has 9 un-identical groups of machines with capacities ranging from 10 kg to 800 kg. On average, it processes 140 jobs per week. It has a problem of late delivery caused by jobs that have different fabrics to be dyed to the same colors and must be dyed together in the same dyeing machine. Scheduling these jobs is complicated because a large portion of them will need re-dyeing and it is not …

Efficiency Improvement Of Picking Process At An Automotive Parts Retailer Warehouse, Phunyisa Saerevatanawoot

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objective of this research is to improve efficiency of picking process to meet customer expectation, hence, increase customer satisfaction and trust. This research proposes three phases of methodology, which are define, propose and implement phase, to increase efficiency of picking process by controlling and minimising picking time. Define phase describes warehouse picking process activities and procedures and defines problems and their effects. Key performance indices are brainstormed based on the problems to identify factors that are able to indicate level of picking process efficiency. In propose phase, customer behaviours, customer types, and time expectations are observed. Opportunities for improvement …

Copper-Silver Conductive Film By Spray Pyrolysis Of Copper-Silver Amine Complexes, Walailuk Limkitnuwat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Copper-silver conductive films were fabricated on glass and polyimide substrates by spray pyrolysis of copper-silver amine complex ink in nitrogen atmosphere. The conductive ink was synthesized by mixing of copper (II) acetate monohydrate, silver oxide, ammonia solution, diethanolamine and distilled water. The effects of molar ratio of copper to silver, spray pyrolysis temperature, sintering time and substrate used were studied. The conductive films obtained contained copper and silver nanoparticles. However, copper-silver alloy particles were not observed. Molar ratio of copper to silver affected copper and silver crystallite sizes. The particle packing density synthesized at 200 oC was more compact than …

Study Of The Cracking Reaction In Ethylene Reactant, Atchariya Anantapanyasut

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this thesis, the main objectives were to study the cracking of ethylene, comparing between thermal cracking and catalytic cracking reactions. The ethylene and nitrogen which atomic ratio 1:1 were used as reactant feed on Al2O3, zeolite-Y and silica-supported tungsten catalysts at 723 K and 25 atm. The inert SiO2 was used to represent the thermal cracking. The catalysts were characterized by NH3-TPD. The product distribution was clearly different between the thermal cracking and catalytic cracking. Thermal cracking produced the olefin products while catalytic cracking produced paraffin products.

การปรับปรุงร้อยละการสกัดในเวลาน้อยที่สุดของไอออนแพลเลเดียมและดีบุกผ่านเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวงโดยตัวควบคุมแบบโมเดลพรีดิกทีฟ, นาตยา ลายเสือ

Chulalongkorn University Theses and Dissertations (Chula ETD)

กระบวนการสกัดไอออนแพลเลเดียมและดีบุกผ่านเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวง เป็นกระบวนการหนึ่งที่ใช้สกัดไอออนโลหะออกจากสารละลายโดยเฉพาะอย่างยิ่งสารละลายที่มีความเข้มข้นต่ำๆ ทั้งนี้ยังสามารถสกัดและนำกลับไอออนโลหะแพลเลเดียมและดีบุกได้ในขั้นตอนเดียว จึงทำให้กระบวนการสกัดผ่านเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวงเป็นที่นิยมมากกว่าวิธีอื่น งานวิจัยนี้ศึกษาแบบจำลองทางคณิตศาสตร์ของกระบวนการสกัดไอออนแพลเลเดียมและดีบุกผ่านเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวง โดยควบคุมค่าความเข้มข้นของไอออนแพลเลเดียมและดีบุกโดยตัวควบคุมแบบโมเดลพรีดิกทีฟและตัวควบคุมแบบพีไอดี พบว่าแบบจำลองทางคณิตศาสตร์ของกระบวนการสกัดของไอออนแพลเลเดียมและดีบุกสามารถใช้ทำนายพฤติกรรมความสัมพันธ์ของตัวแปรต่างๆในระบบได้เป็นอย่างดี โดยมีค่ากำลังสองน้อยที่สุดของไอออนแพลเลเดียมและดีบุกอยู่ที่ 6.67 และ 11.41 และมีค่าร้อยละการสกัดของไอออนแพลเลเดียม 97.53 และค่าร้อยละการสกัดของไอออนดีบุก 25.43 ผลการควบคุมแสดงให้เห็นว่าตัวควบคุมแบบพีไอดีและตัวควบคุมแบบโมเดลพรีดิกทีฟสามารถควบคุมความเข้มข้นของไอออนแพลเลเดียมและดีบุกได้ดี และในกรณีที่ค่าพารามิเตอร์ของกระบวนการเกิดความคลาดเคลื่อนตัวควบคุมแบบโมเดลพรีดิกทีฟมีสมรรถนะทีดีกว่าตัวควบคุมแบบพีไอดีโดยพิจารณาจากค่าดัชนีชี้วัดไอเออี

การควบคุมแบบโมเดลพรีดิกทีฟในการสกัดแบบเสริมฤทธิ์ของไอออนนีโอดิเมียมด้วยเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวง, วรรษมนต์ คอนเอม

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้นำเสนอการประยุกต์ใช้การควบคุมแบบโมเดลพรีดิกทีฟโดยเปรียบเทียบกับการควบคุมแบบพีไอดีสำหรับการควบคุมความเข้มข้นของไอออนนีโอดิเมียมในการสกัดแบบเสริมฤทธิ์ผ่านเยื่อแผ่นเหลวที่พยุงด้วยเส้นใยกลวงเพื่อควบคุมความเข้มข้นของไอออนนีโอดิเมียมขณะออกจากมอดูลของเส้นใยกลวงให้เข้าสู่ค่าเป้าหมาย โดยอาศัยค่าไอเอดีเป็นดัชนีชี้วัด ระบบที่ศึกษาคือ การสกัดไอออนนีโอดิเมียมในสารละลายกรดไนตริก สารสกัดคือ D2EHPA และ TOPO ผสมกันในอัตราส่วน 1:1 สารละลายนำกลับคือกรดซัลฟิวริกความเข้มข้น 1 โมลต่อลิตร รูปแบบการไหลผ่านมอดูลเส้นใยกลวงแบบไหลผ่านครั้งเดียวและสารละลายป้อนไหลสวนทางกับสารละลายนำกลับ และศึกษาสมรรถนะของตัวควบคุมทั้งสองแบบ เมื่อมีความคลาดเคลื่อนระหว่างแบบจำลองกับกระบวนการจริง ที่สภาวะปกติผลการจำลองแสดงให้เห็นว่า ตัวควบคุมทั้งแบบพีไอดีและโมเดลพรีดิกทีฟสามารถควบคุมความเข้มข้นของไอออนนีโอดิเมียมให้เข้าสู่ค่าเป้าหมายได้เร็วกว่ากระบวนการที่ไม่ใช้ตัวควบคุม โดยตัวควบคุมแบบโมเดลพรีดิกทีฟสามารถควบคุมความเข้มข้นของไอออนนีโอดิเมียมให้เข้าสู่ค่าเป้าหมายได้เร็วกว่าตัวควบคุมแบบพีไอดี และเมื่อแบบจำลองมีความคลาดเคลื่อนไปจากกระบวนการจริง ตัวควบคุมทั้งสองแบบสามารถควบคุมความเข้มข้นให้เข้าสู่ค่าเป้าหมายได้ โดยตัวควบคุมแบบโมเดลพรีดิกทีฟให้สมรรถนะที่ดีกว่าการควบคุมแบบพีไอดีทั้งกรณีที่แบบจำลองมีความถูกต้องและแบบจำลองมีความคลาดเคลื่อนไปจากกระบวนการจริง

การประยุกต์ใช้กระบวนการลำดับชั้นเชิงวิเคราะห์ในการเลือกทำเลที่ตั้งศูนย์กระจายสินค้า : กรณีศึกษาศูนย์กระจายสินค้าธุรกิจร้านสะดวกซื้อ, วราภรณ์ โลหิตปุระ

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้เป็นการประยุกต์ใช้กระบวนการลำดับชั้นเชิงวิเคราะห์ (Analytic Hierarchy Process) ในการกำหนดทำเลที่ตั้งศูนย์กระจายสินค้าแห่งใหม่เพื่อรองรับปริมาณสินค้าที่เพิ่มขึ้นในอีก 3 ปีข้างหน้า โดยมีกรณีศึกษาของงานวิจัย เป็นศูนย์กระจายสินค้าที่ดำเนินธุรกิจด้านการกระจายสินค้าให้กับร้านสะดวกซื้อของบริษัท และนอกจากนี้ยังมีวัตถุประสงค์เพื่อศึกษา และวิเคราะห์ปัจจัยเชิงปริมาณ และปัจจัยเชิงคุณภาพที่มีผลต่อการเลือกทำเลที่ตั้งศูนย์กระจายสินค้าของธุรกิจร้านสะดวกซื้อ กระบวนการลำดับชั้นเชิงวิเคราะห์เป็นกระบวนการสนับสนุนการตัดสินใจที่มีเหตุผลสามารถใช้ในการตัดสินใจ ที่เกี่ยวข้องกับปัจจัยทั้งเชิงปริมาณ และเชิงคุณภาพ อีกทั้งยังสามารถวัดความสอดคล้องของการตัดสินใจในแต่ละปัจจัย และนอกจากนี้งานวิจัยยังได้มีการวิเคราะห์ต้นทุนค่าขนส่งของทางเลือกของที่ตั้งที่พิจารณาประกอบการตัดสินใจร่วมด้วย งานวิจัยได้พิจารณาทางเลือกของที่ตั้งศูนย์กระจายสินค้าจำนวน 3 จังหวัด ได้แก่ จังหวัดนครสวรรค์ จังหวัดปทุมธานี และจังหวัดสุพรรณบุรี โดยพิจารณาปัจจัยต่างๆดังนี้ ต้นทุนค่าขนส่ง ต้นทุนการลงทุน แรงงาน ความเสี่ยงน้ำท่วม การเข้าถึงถนน การเข้าถึงลูกค้า และทัศนคติของชุมชน การวิจัยได้นำปัจจัยและทางเลือกของทำเลที่ตั้งศูนย์กระจายสินค้า มาพัฒนาเป็นโครงสร้างแผนภูมิลำดับชั้นตามกระบวนการลำดับชั้นเชิงวิเคราะห์ ผลการวิจัยพบว่า ผู้ตัดสินใจให้ความสำคัญกับปัจจัยตามลำดับความสำคัญ ดังนี้ ต้นทุนค่าขนส่ง การเข้าถึงลูกค้า ความเสี่ยงน้ำท่วม แรงงาน ต้นทุนการลงทุน ทัศนคติของชุมชน และการเข้าถึงถนน และผู้ตัดสินใจให้ความสำคัญของทางเลือกภายใต้ปัจจัยต่างๆ ตามลำดับความสำคัญ ดังนี้ จังหวัดนครสวรรค์ จังหวัดปทุมธานี และจังหวัดสุพรรณบุรี เมื่อพิจารณาร่วมกับผลการวิเคราะห์ต้นทุนค่าขนส่งพบว่า ทางเลือกที่เหมาะสมที่สุดคือจังหวัดนครสวรรค์ซึ่งมีต้นทุนค่าขนส่งต่ำที่สุด

Treatment Of Calibration Uncertainty In Multi-Baseline Cross-Correlation Searches For Gravitational Waves, J. T. Whelan, E. L. Robinson, Joseph D. Romano, E. H. Thrane

Physics & Astronomy Faculty Publications

Uncertainty in the calibration of gravitational wave (GW) detector data leads to systematic errors, which must be accounted for in setting limits on the strength of GW signals. When cross-correlation measurements are made using data from a pair of instruments, as in searches for a stochastic GW background, the calibration uncertainties of the individual instruments can be combined into an uncertainty associated with the pair. With the advent of multi-baseline GW observation (e.g., networks consisting of multiple detectors such as the LIGO observatories and Virgo), a more sophisticated treatment is called for. We have described how the correlations between calibration …

Pt-Symmetric Acoustics, Xuefeng Zhu, Hamidreza Ramezani, Chengzhi Shi, Jie Zhu, Xiang Zhang

Physics & Astronomy Faculty Publications

We introduce here the concept of acoustic parity-time (PT) symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT -symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT -symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

Vanishing Power Lines And Emerging Distributed Generation, Gina S. Warren

Faculty Scholarship

Experts predict that distributed energy will contribute as much as twenty percent of the U.S. power supply by 2020. While no one will wake up tomorrow morning to an entirely new energy distribution system — complete with solar panels on the roof and a wind turbine in the back yard — distributed generation is receiving significant attention as the disruptive technology that will ultimately revolutionize the way energy is delivered in the United States. The reason for this shift is, in part, due to new technology that allows for more flexible localized generation of energy, and in part due to …

The Role Of Behavioral And Cognitive Cultural Orientation On Mexican American College Students’ Life Satisfaction, Lizette Ojeda, Lisa M. Edwards, Erin E. Harding, Brandy Piña-Watson

College of Education Faculty Research and Publications

We examined the role of behavioral (acculturation and enculturation) and cognitive cultural orientation (independent and interdependent self-construal) on Mexican American college students’ life satisfaction. Analyses explained 28% of the variance in life satisfaction, with social class, grade point average, and independent self-construal being unique predictors. Furthermore, enculturation was associated with increasing life satisfaction among those low in interdependent self-construal, whereas acculturation was associated with decreasing life satisfaction among those high in independent self-construal. Implications and directions for future research are discussed.

A Static Voltage Security Region For Centralized Wind Power Integration-Part I: Concept And Method, Tao Ding, Qinglai Guo, Rui Bo, Hongbin Sun, Boming Zhang

Electrical and Computer Engineering Faculty Research & Creative Works

When large wind farms are centrally integrated in a power grid, cascading tripping faults induced by voltage issues are becoming a great challenge. This paper therefore proposes a concept of static voltage security region to guarantee that the voltage will remain within operation limits under both base conditions and N-1 contingencies. For large wind farms, significant computational effort is required to calculate the exact boundary of the proposed security region. To reduce this computational burden and facilitate the overall analysis, the characteristics of the security region are first analyzed, and its boundary components are shown to be strictly convex. Approximate …

A Study Of Self-Concept In At-Risk Middle School Children Related To Behavior And Academic Performance, Tara Wade Franklin

Electronic Theses and Dissertations

The purpose of this study was to explore the factors that are associated with the development of self-concept and how self-concept influences or interacts with academic performance and behavior. This research study asked two questions: (1) what assists in the development of self-concept, and (2) how does self-concept impact academic performance and behavior in at-risk middle school students? Using evidence-based research, parental involvement, gender, and ethnicity were selected as key factors associated with the development of self-concept in adolescence. This study proposed that students with high self-concept would have positive academic and behavioral performance. Consequently, students with low self-concept would …

Collision And Diffusion In Microwave Breakdown Of Nitrogen Gas In And Around Microgaps, J. D. Campbell, A. Bowman Iii, G. T. Lenters, Stephen K. Remillard

Faculty Publications

The microwave induced breakdown of N-2 gas in microgaps was modeled using the collision frequency between electrons and neutral molecules and the effective electric field concept. Low pressure breakdown at the threshold electric field occurs outside the gap, but at high pressures it is found to occur inside the microgap with a large threshold breakdown electric field corresponding to a very large electron oscillation amplitude. Three distinct pressure regimes are apparent in the microgap breakdown: a low pressure multipactor branch, a mid-pressure Paschen branch, both of which occur in the space outside the microgap, and a high pressure diffusion-drift branch, …

Embedded Star Formation In S4g Galaxy Dust Lanes., Debra M. Elmegreen, Bruce G. Elmegreen, Santiago Erroz-Ferrer, Johan H. Knapen, Yaron Teich, Mark Popinchalk, E. Athanassoula, Albert Bosma, Sebastien Comeron, Yuri N. Efremov, Dimitri A. Gadotti, Armando Gil De Paz, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Jarkko Laine, Eija Laurikainen, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Heikki Salo, Mark Seibert, Kartik Sheth

Faculty and Staff Scholarship

Star-forming regions that are visible at 3.6 μm and Hα but not in the u, g, r, i, z bands of the Sloan Digital Sky Survey are measured in five nearby spiral galaxies to find extinctions averaging ∼3.8 mag and stellar masses averaging ∼5 × 104 M. These regions are apparently young star complexes embedded in dark filamentary shock fronts connected with spiral arms. The associated cloud masses are ∼107 M. The conditions required to make such complexes are explored, including gravitational instabilities in spiral-shocked gas and compression of incident clouds. We find that instabilities are too slow for a …

Constraining The Age Of The Ngc 4565 Hi Disk Warp : Determining The Origin Of Gas Warps., David J. Radburn-Smith, Roelof S. De Jong, David Streich, Eric F. Bell, Julianne J. Dalcanton, Andrew E. Dolphin, Adrienne M. Stilp, Antonela Monachesi, Benne W. Holwerda, Jeremy Bailin

Faculty and Staff Scholarship

We have mapped the distribution of young and old stars in the gaseous H i warp of NGC 4565. We find a clear correlation of young stars (< 600 Myr) with the warp but no coincident old stars (> 1 Gyr), which places an upper limit on the age of the structure. The formation rate of the young stars, which increased ∼ 300 Myr ago relative to the surrounding regions, is (6.3+2.5 −1.5) × 10−5 M yr−1 kpc−2. This implies a ∼ 60 ± 20 Gyr depletion time of the H i warp, similar to the timescales calculated for the outer H i disks of nearby spiral galaxies. While some stars …

Ghosts I : A New Faint Very Isolated Dwarf Galaxy At D = 12 ± 2 Mpc., Antonela Monachesi, Eric F. Bell, David J. Radburn-Smith, Roelof S. De Jong, Jeremy Bailin, Julianne J. Dalcanton, Benne W. Holwerda, H. Alyson Ford, David Streich, Marija Vlajic, Daniel B. Zucker

Faculty and Staff Scholarship

We report the discovery of a new faint dwarf galaxy, GHOSTS I, using HST/ACS data from one of our GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) fields. Its detected individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color–magnitude diagrams (CMDs) to compare with the galaxy’s CMD, we find that the colors and magnitudes of GHOSTS I’s individual stars are most consistent with being young helium-burning and asymptotic giant branch stars at a distance of ∼12±2 Mpc. Morphologically, GHOSTS I appears to be actively forming stars, so we tentatively classify …

Morphological Parameters Of A Spitzer Survey Of Stellar Structure In Galaxies., Benne W. Holwerda, J. C. Munoz-Mateos, S. Comeron, S. Meidt, K. Sheth, S. Laine, J. L. Hinz, M. W. Regan, A. Gil De Paz, K. Menendez-Delmestre, M. Seibert, T. Kim, T. Mizusawa, E. Laurikainen, H. Salo, J. Laine, D. A. Gadotti, D. Zaritsky, S. Erroz-Ferrer, L. C. Ho, J. H. Knapen, E. Athanassoula, A. Bosma, N. Pirzkal

Faculty and Staff Scholarship

The morphology of galaxies can be quantified to some degree using a set of scale-invariant parameters. Concentration (C), asymmetry (A), smoothness (S), the Gini index (G), the relative contribution of the brightest pixels to the secondorder moment of the flux (M20), ellipticity (E), and the Gini index of the second-order moment (GM) have all been applied to morphologically classify galaxies at various wavelengths. Here, we present a catalog of these parameters for the Spitzer Survey of stellar structure in Galaxies, a volume-limited, near-infrared (NIR) imaging survey of nearby galaxies using the 3.6 and 4.5μm channels of the Infrared Array Camera …

Gravity Effect On Electrical Field Generation And Charge Carriers Transfer During Combustion Synthesis Of Sulfides, A. A. Markov, I. A. Filimonov, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

The effect of gravity on the electric potential generated by the combustion synthesis of zinc sulfide is analyzed using the numerical simulation. Recent experimental studies on generation of electric voltage during combustion synthesis of zinc sulfide (ZnS) have revealed high voltage signals (4 V) with duration about 1 s, which are much higher than those produced by the gas–solid and solid–solid combustion reactions studied previously. These data have raised the question about mechanism of such a phenomenon. In our previous work we developed a novel (distributed) model describing the electric potential generation during combustion synthesis of sulfides (CSS) that didn't …

Fabrication Of Yttrium Ferrite Nanoparticles By Solution Combustion Synthesis, A. A. Saukhimov, Mkhitar A. Hobosyan, Gamage C. Dannangoda, N. N. Zhumabekova, S. E. Kumekov

Physics & Astronomy Faculty Publications

The ternary oxide system Y-Fe-O presents fascinating magnetic properties that are sensitive to the crystalline size of particles. There is a major challenge to fabricate these materials in nano-crystalline forms due to particle conglomeration during nucleation and synthesis. In this paper we report the fabrication of nano sized crystalline yttrium ferrite by solution combustion synthesis (SCS) where yttrium and iron nitrates were used as metal precursors with glycine as a fuel. The magnetic properties of the product can be selectively controlled by adjusting the ratio of glycine to metal nitrates. Yttrium ferrite nano-powder was obtained by using three concentration of …

Free-Energy Calculations For Semi-Flexible Macromolecules: Applications To Dna Knotting And Looping, Stefan M. Giovan, Robert G. Scharein, Andreas Hanke, Stephen D. Levene

Physics & Astronomy Faculty Publications

We present a method to obtain numerically accurate values of configurational free energies of semiflexible macromolecular systems, based on the technique of thermodynamic integration combined with normal-mode analysis of a reference system subject to harmonic constraints. Compared with previous free-energy calculations that depend on a reference state, our approach introduces two innovations, namely, the use of internal coordinates to constrain the reference states and the ability to freely select these reference states. As a consequence, it is possible to explore systems that undergo substantially larger fluctuations than those considered in previous calculations, including semiflexible biopolymers having arbitrary ratios of contour …

Report To The Chicago Park District On Conflicts With Ring-Billed Gulls And The 2014 Integrated Ring-Billed Gull Damage Management Project, M. L. Bloomquist, J.W. Hartmann, T.G. Guerrant, S. F. Beckerman, R. M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

The large ring-billed gull (Larus delawarensis) population in the City of Chicago has caused various conflicts including general nuisance, property damage, economic losses, and threats to human health and safety. Several studies have shown a relationship between ring-billed gulls and increased levels of fecal indicator bacteria (FIB) such as Escherichia coli (E. coli) in nearshore waters. Results of tests for E. coli have led to the issuance of swim advisories at Chicago beaches.

The objectives of the Chicago Ring-billed Gull Damage Management Project were to (1) reduce the local production of ring-billed gulls, (2) reduce the …

Incorporating Cold-Air Pooling Into Downscaled Climate Models Increases Potential Refugia For Snow-Dependent Species Within The Sierra Nevada Ecoregion, Ca, Jennifer A. Curtis, Lorraine E. Flint, Alan L. Flint, Jessica D. Lundquist, Brian Hudgens, Erin E. Boydston, Julie K. Young

United States Department of Agriculture Wildlife Services: Staff Publications

We present a unique water-balance approach for modeling snowpack under historic, current and future climates throughout the Sierra Nevada Ecoregion. Our methodology uses a finer scale (270 m) than previous regional studies and incorporates cold-air pooling, an atmospheric process that sustains cooler temperatures in topographic depressions thereby mitigating snowmelt. Our results are intended to support management and conservation of snow-dependent species, which requires characterization of suitable habitat under current and future climates. We use the wolverine (Gulo gulo) as an example species and investigate potential habitat based on the depth and extent of spring snowpack within four National …

Calving Location Selection Patterns Of Saiga Antelope In Mongolia, B. Buuveibaatar, T. K. Fuller, J. K. Young, J. Berger

United States Department of Agriculture Wildlife Services: Staff Publications

Habitat selection for calving by ungulates is an important behavioral trait because it affects neonate survival. Generally, ungulate calving site selection varies by vulnerability to predators, local topography, habitat quality and level of human disturbance. The Mongolian saiga (Saiga tatarica mongolica) is endemic to Mongolia where a threatened population of ∼7000 exists in the northern Gobi Desert. We analyzed factors that could affect selection of saiga calving locations in the Sharga Nature Reserve, western Mongolia, using data obtained from ground surveys over 4 years between 2008 and 2012. Multiple factors explain calving location selection by saiga antelopes, based …