Physical Sciences and Mathematics Commons^™

Photofading Of Black Dyes In Cotton And Polyester Fibers Resulting From Environmental Exposure To Sunlight, Maggie E. Mahaney

Honors Theses

Color is one of the most important properties analyzed during forensic fiber examinations due to its discriminatory power. Differing colors in fibers are usually sufficient grounds for exclusion, but in cases where a lengthy period has passed between crime commission and evidence recovery, the high probability of environmental degradation having altered the questioned fibers’ properties could lead to false exclusions. Photofading, the loss of color resulting from exposure to light, is a common form of degradation observed in fibers. Although well-known in the dyeing industry, it is not typically factored into forensic fiber examinations. Published photofading research has been limited …

Small Island Taphonomy In Western Australia, Courtney J. Newberry

Honors Theses

Forensic death investigations rely on postmortem interval estimations to establish a timeline surrounding a decedent’s death. Several methods are used, often together, to make such estimations. One of the main methods is the evaluation of the stage of decomposition; although decomposition follows the same general steps, the length of the process can vary by location and environmental factors. Animal scavenging can also impact decomposition by consuming flesh and impacting insect activity on the remains.

This study investigates the scavenging guilds and rate of decomposition of pig (Sus scrofa) legs on Rottnest Island, Australia. Three sites with unique environments were selected …

Determining The Interference Of Lactate And Lactate Dehydrogenase In An Ethanol Enzyme Assay, Julia Liebl

Master's Theses

Enzymatic ethanol assays are widely used to determine blood alcohol content for individuals admitted to a hospital. In some instances, this hospital data is later used as evidence in a court of law, most commonly in DUI cases. As the enzymatic assay targets, but does not exclusively measure ethanol, it is theoretically possible that interference could occur and produce a falsely elevated result, leading to wrongful convictions or other consequences. This project examined the potential of clinically relevant levels of one potential interferant, lactate and the hepatic enzyme lactate dehydrogenase (LDH) to cause significant and falsely elevated results. Threshold levels …

Tin Assisted Fully Exposed Platinum Clusters Stabilized On Defect-Rich Graphene For Dehydrogenation Reaction, Jiayun Zhang, Yuchen Deng, Xiangbin Cai, Yunlei Chen, Mi Peng, Zhimin Jia, Zheng Jiang, Pengju Ren, Siyu Yao, Jinglin Xie, Dequan Xiao, Xiao-Dong Wen, Ning Wang, Hongyang Liu, Ding Ma

Chemistry and Chemical Engineering Faculty Publications

Tin assisted fully exposed Pt clusters are fabricated on the core-shell nanodiamond@graphene (ND@G) hybrid support (a-PtSn/ND@G). The obtained atomically dispersed Pt clusters, with an average Pt atom number of 3, were anchored over the ND@Gsupport by the assistance of Sn atoms as a partition agent and through the Pt-C bond between Pt clusters and defect-rich graphene nanoshell. The atomically dispersed Pt clusters guaranteed a full metal availability to the reactants, a high thermal stability, and an optimized adsorption/desorption behavior. It inhibits the side reactions and enhances catalytic performance in direct dehydrogenation of n-butane at a low temperature of 450 °C, …

A Versatile Route To Fabricate Single Atom Catalysts With High Chemoselectivity, Xiaohui He, Qian He, Yuchen Deng, Mi Peng, Hongyu Chen, Ying Zhang, Siyu Yao, Mengtao Zhang, Dequan Xiao, Ding Ma, Binghui Ge, Hongbing Ji

Chemistry and Chemical Engineering Faculty Publications

Preparation of single atom catalysts (SACs) is of broad interest to materials scientists and chemists but remains a formidable challenge. Herein, we develop an efficient approach to synthesize SACs via a precursor-dilution strategy, in which metalloporphyrin (MTPP) with target metals are co-polymerized with diluents (tetraphenylporphyrin, TPP), followed by pyrolysis to N-doped porous carbon supported SACs (M₁/N-C). Twenty-four different SACs, including noble metals and non-noble metals, are successfully prepared. In addition, the synthesis of a series of catalysts with different surface atom densities, bi-metallic sites, and metal aggregation states are achieved. This approach shows remarkable adjustability and generality, providing …

Anchoring Cu 1 Species Over Nanodiamond-Graphene For Semi-Hydrogenation Of Acetylene, Fei Huang, Yuchen Deng, Yunlei Chen, Xiangbin Cai, Mi Peng, Zhimin Jia, Jinglin Xie, Dequan Xiao, Xiaodong Wen, Ning Wang, Zheng Jiang, Hongyang Liu, Ding Ma

Chemistry and Chemical Engineering Faculty Publications

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamondgraphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding …

Au@H-Al2o3 Analogic Yolk–Shell Nanocatalyst For Highly Selective Synthesis Of Biomass-Derived D-Xylonic Acid Via Regulation Of Structure Effects, Jiliang Ma, Zewei Liu, Junlong Song, Linxin Zhong, Dequan Xiao, Hongxia Xi, Xuehui Li, Runcang Sun, Xinwen Peng

Chemistry and Chemical Engineering Faculty Publications

Selective oxidation of biomass-based monosaccharides into value-added sugar acids is highly desired, but limited success of producing D-xylonic acid has been achieved. Herein, we report an efficient catalyst system, viz., Au nanoparticles anchored on the inner walls of hollow Al₂O₃ nanospheres (Au@h- Al₂O₃), which could catalyze the selective oxidation of D-xylose into D-xylonic acid under base-free conditions. The mesoporous Al₂O₃ shell as the adsorbent first adsorbed D-xylose. Then, the interface of Au nanoparticles and Al₂O₃ as active sites spontaneously dissociated O₂, and …

Atomically Dispersed Pd On Nanodiamond/Graphene Hybrid For Selective Hydrogenation Of Acetylene, Fei Huang, Yuchen Deng, Yunlei Chen, Xiangbin Cai, Mia Peng, Zhimin Jia, Pengju Ren, Dequan Xiao, Xiaodong Wen, Ning Wang, Hongyang Liu, Ding Ma

Chemistry and Chemical Engineering Faculty Publications

An atomically dispersed palladium (Pd) catalyst supported onto a defective nanodiamond-graphene (ND@G) is reported here for selective hydrogenation of acetylene in the presence of abundant ethylene. The catalyst exhibits remarkable performance for the selective conversion of acetylene to ethylene: high conversion (100%), ethylene selectivity (90%), and good stability (i.e., steady for at least 30 hours). The unique struc-ture of the catalyst (i.e., atomically dispersion of Pd atoms on graphene through Pd-C bond anchoring) ensure the facile desorption of ethylene against the over-hydrogenation of ethylene to undesired ethane, which is the key for the outstanding selectivity of the catalyst.

A Hierarchical Approach For Creating Electrically Conductive Network Structure In Polyurethane Nanocomposites Using A Hybrid Of Graphene Nanoplatelets, Carbon Black And Multi-Walled Carbon Nanotubes, Pashupati Pokharel, Dequan Xiao, Folarin Erogbogbo, Ozgur Keles, Dai Soo Lee

Chemistry and Chemical Engineering Faculty Publications

Hierarchical organization of carbon nanomaterials is the best strategy to combine desirable factors and synergistically impart mechanical and electrical properties to polymers. Here, we investigate the relaxation behavior of carbon nanofillers filled polyurethane (PU) with special reference to particle size and aspect ratio, filler morphology, filler loading to understand the conductive network formation of fillers in the PU matrix. Typically, an addition of 2 wt% hybrid fillers of graphene nanoplatelets (GNPs), conductive carbon black (CB) and multiwalled carbon nanotubes (MWCNTs) in PU at 1:1:2 mass ratio (GCM112-PU2) showed lowest surface resistivity ~10^6.8 ohm/sq along with highest improved mechanical properties. …

An Unexpected Restructuring Of Combustion Soot Aggregates By Subnanometer Coatings Of Polycyclic Aromatic Hydrocarbons, Chao Chen, Xiaolong Fan, Tasneem Shaltout, Chong Qiu, Yan Ma, Andrew Goldman, Alexei F. Khalizov

Chemistry and Chemical Engineering Faculty Publications

We investigated the effect of thin polycyclic aromatic hydrocarbon (PAH) coatings on the structure of soot aggregates. Soot aerosol from an inverted diffusion burner was size classified, thermally denuded, coated with six different PAHs, and then characterized using scanning electron microscopy, light scattering, and mass-mobility measurements. Contrary to our expectation, significant restructuring was observed in the presence of subnanometer layers of pyrene, fluoranthene, and phenanthrene. These PAHs remained in subcooled liquid state in thin films, whereby the liquid layer acted as a lubricant, reducing the force required to initiate the restructuring. Thin layers of PAH of higher melting temperatures (perylene, …

Development And Implementation Of Problem-Based Chemistry Experiments For Engineering Students In A Multi-Disciplinary Course, Tiffany Hesser, Stephanie R. Bunyea

Chemistry and Chemical Engineering Faculty Publications

This paper will describe the implementation and continuing development of five problem based laboratory experiments in a general chemistry course designed specifically for multiple disciplines of engineering students at the University of New Haven. The Problem Based Laboratory Experiments (PBLE) were developed to provide students with the opportunity to perform and develop experimental procedures working in interdisciplinary teams, while achieving a greater understanding of the role of chemistry in engineering fields. In each PBLE, students first complete a traditional chemistry experiment to gain an understanding of the chemical concepts and to become familiar with executing a written procedure with a …

Highly Selective Hydrogenation And Hydrogenolysis Using A Copper-Doped Porous Metal Oxide Catalyst, Laurene Petitjean, Raphael Gagne, Evan Beach, Dequan Xiao, Paul Anastas

Chemistry and Chemical Engineering Faculty Publications

A copper-doped porous metal oxide catalyst in combination with hydrogen shows selective and quantitative hydrogenolysis of benzyl ketones and aldehydes, and hydrogenation of alkenes. The approach provides an alternative to noble-metal catalysed reductions and stoichiometric Wolff-Kishner and Clemmensen methods.

Multiple-Choice Testing Using Immediate Feedback-Assessment Technique (If At®) Forms: Second-Chance Guessing Vs. Second-Chance Learning?, Jeremy D. Merrel, Pier F. Cirillo, Pauline M. Schwartz, Jeffrey Webb

Chemistry and Chemical Engineering Faculty Publications

Multiple choice testing is a common but often ineffective method for evaluating learning. A newer approach, however, using Immediate Feedback Assessment Technique (IF AT®, Epstein Educational Enterprise, Inc.) forms, offers several advantages. In particular, a student learns immediately if his or her answer is correct and, in the case of an incorrect answer, has an opportunity to provide a second response and receive partial credit for a correct second attempt. For a multiple choice question with five possible answers, the IF AT® form covers spaces labeled A through E with a thin opaque film; when the film is scratched away, …

Exploring The Use Of Faded Worked Examples As A Problem Solving Approach For Underprepared Students, Tiffany Hesser, Jess L. Gregory

Chemistry and Chemical Engineering Faculty Publications

It is not uncommon for students to find themselves underprepared when entering a post secondary institution. In additional to lower levels of academic achievement, underprepared students may not be aware that they lack the skills needed to be successful and effectively acquire and process information. Because of this, students that enter post-secondary institutions underprepared often require more support in and out of the college classroom.

In computational based classes, such as math, engineering, chemistry or physics, this support often includes an introduction to effective problem solving strategies. This study introduced faded worked examples as a problem solving approach to students …

Analysis Of A Chemical Model System Leading To Chiral Symmetry Breaking: Implications For The Evolution Of Homochirality, Brandy N. Morneau, Jaclyn M. Kubala, Carl Barratt, Pauline Schwartz

Chemistry and Chemical Engineering Faculty Publications

Explaining the evolution of a predominantly homochiral environment on the early Earth remains an outstanding challenge in chemistry. We explore here the mathematical features of a simple chemical model system that simulates chiral symmetry breaking and amplification towards homochirality. The model simulates the reaction of a prochiral molecule to yield enantiomers via interaction with an achiral surface. Kinetically, the reactions and rate constants are chosen so as to treat the two enantiomeric forms symmetrically. The system, however, incorporates a mechanism whereby a random event might trigger chiral symmetry breaking and the formation of a dominant enantiomer; the non-linear dynamics of …

Ipads In The Science Laboratory: Experience In Designing And Implementing A Paperless Chemistry Laboratory Course, Tiffany Hesser, Pauline Schwartz

Chemistry and Chemical Engineering Faculty Publications

In the fall of 2012, 20 General Chemistry Honors students at the University of New Haven were issued the new iPad 3 to incorporate these devices both in the classroom and the laboratory. This paper will focus on the integration of the iPad into the laboratory curriculum while creating a paperless experience, an environment where no paper would enter or be used for the laboratory over the course of the year. Specific apps were chosen that would allow for an easy transition of course materials into an electronic format. After a transition period for the students and instructor, the overall …

Effects Of Thiophene Units On Substituted Benzothiadiazole And Benzodithiophene Copolymers For Photovoltaic Applications, Ping Ding, Yingping Zou, Cheng-Che Chu, Dequan Xiao, Chain-Shu Hsu

Chemistry and Chemical Engineering Faculty Publications

Two conjugated copolymers, P1 and P2, comprising of benzodithiophene and 5, 6-dioctyloxy-benzothiadiazole (DOBT) derivatives with/without thiophene unit, were synthesized via Stille cross-coupling polymerization reaction. These copolymers are promising for the applications in BHJ solar cells due to their good solubilities， proper thermal stability and moderate hole mobility as well as low bandgap. The photovoltaic properties of the copolymers were investigated based on the blend of the different polymer/PC71BM weight ratio under AM1.5G illumination, 100 mW/cm2. The device with ITO/PEDOT:PSS/P2: PC71BM (1:2, w/w)/Ca/Al gave relatively better photovoltaic performance, with a power conversion efficiency of 1.55%.

Analysis Of The Penney-Ante Game Using Difference Equations: Development Of An Optimal And A Mixed-Strategies Protocol, Carl Barratt, Pauline Schwartz

Chemistry and Chemical Engineering Faculty Publications

Penney-Ante is a well known two-player (Player I and Player II) game based on an information paradox. We present a new approach, using difference-equations, to analyzing the outcome for each player. One strategy yields a winning outcome of 75% for Player II, the player playing second. The approach also permits investigation of non-optimal strategies, and demonstrates how mixing of such strategies can be used to tune the winning edge of either player. We generalize the analysis to accommodate the possibility of a biased coin.

Kinetic Models Of The Prebiotic Replication Of Dsrna Under Thermal Cycling Conditions, Pauline Schwartz, Dante M. Lepore, Carl Barratt

Chemistry and Chemical Engineering Faculty Publications

We present computational models for the replication of double stranded RNA (dsRNA) or related macromolecules under thermal cycling conditions that would reflect prebiotic (i.e. non-enzymatic) environments. Two models of the replication of dsRNA are represented as multi-step chemical systems. The objective of this investigation was to better understand the kinetic features of such chemical systems. It is shown that thermal cycling in a chemical system is advantageous (relative to a fixed temperature) if there are two competing reactions, one favored at high temperature and one favored at low temperature. For the prebiotic replication of dsRNA, a high temperature favors formation …

Effect Of Freshman Chemistry On Student Performance In Sophomore Engineering Courses, Michael A. Collura, Shannon Ciston, Nancy Ortins Savage

Chemistry and Chemical Engineering Faculty Publications

The role of first year chemistry courses in engineering programs varies somewhat across programs and disciplines. Clearly most engineering majors will encounter chemistry topics of a general nature in some of their upper-level course work. The purpose of requiring chemistry in the first year, however, goes well beyond learning chemical concepts. As a quantitative science, chemistry requires the use of math, principally algebra, on a regular basis in solving various problems. Students should gain an appreciation of the importance of units in solving problems should come to understand the difference between implicit and explicit properties and should develop other quantitative …

Computational Models Of Chemical Systems Inspired By Braess’ Paradox, Dante Lepore, Carl Barratt, Pauline Schwartz

Chemistry and Chemical Engineering Faculty Publications

Systems chemistry is a new discipline which investigates the interactions within a network of chemical reactions. We have studied several computational models of chemical systems inspired by mathematical paradoxes and have found that even simple systems may behave in a counterintuitive, non-linear manner depending upon various conditions. In the present study, we modeled a set of reactions inspired by one such paradox, Braess’ paradox, an interesting phenomenon whereby the introduction of additional capacity (e.g. pathways) in some simple network systems can lead to an unexpected reduction in the overall flow rate of “traffic” through the system. We devised several chemical …

Web Based Classes For Enhancement Of Prelaboratory Lectures, Tiffany Hesser, Michael Collura

Chemistry and Chemical Engineering Faculty Publications

The use of web classes, such as Tegrity Campus1, as a supplement to pre laboratory reading or a replacement for pre laboratory lectures could become a standard tool in laboratory education protocol. In classes with multiple lab sections and instructors, pre laboratory lectures can lack consistency and it can be difficult to gauge the students’ level of preparation. With the ever increasing exposure to technology, students generally prefer information in a digital and multimedia form, rather than textbook readings. Therefore, this method can prove to better prepare students prior to laboratory experiments, increasing the overall understanding of the chemical reactions …

Systems Chemistry And Parrondo’S Paradox: Computational Models Of Thermal Cycling, Daniel C. Osipovitch, Carl Barratt, Pauline M. Schwartz

Chemistry and Chemical Engineering Faculty Publications

A mathematical concept known as Parrondo’s paradox motivated the development of several novel computational models of chemical systems in which thermal cycling was explored. In these kinetics systems we compared the rates of formation of product under cycling temperature and steady-sate conditions. We found that a greater concentration of product was predicted under oscillating temperature conditions. Our computational models of thermal cycling suggest new applications in chemical and chemical engineering systems.