Conductivity Measurements of a Thermoelectric Nanomaterial through THz Spectroscopy

In today’s society there is a great demand on energy output—in the United States alone we rely heavily on non-renewable energy sources. Thermoelectric materials may be able to be used to create more efficient energy systems or recover wasted heat from inefficient technologies. This paper focuses on the conductivity of a new thermoelectric material that incorporates copper into a tellurium nanowire PEDOT:PSS material. The addition of copper seems to increase the conductivity of the material, although the exact relationship between the percentage of copper to tellurium and its affect on the conductivity is uncertain from the results

Transient Photoconductivity of a Thermoelectric Nanomaterial PEDOT:PSS with TeCu nanowires

Thermoelectric materials are able to transfer heat energy into electrical energy. They have many important applications, and an increased understanding of them would allow the scientific community to develop more efficient thermoelectrics. We provide here transient photoconductivity measurements of a thermoelectric nanomaterial - PEDOT:PSS with TeCu nanowires on quartz substrate. Increased copper concentration in nanowires decreases photoconductivity in both transmission and reflectance measurements. Fermi blocking provides a reasonable explanation for this decrease in photoconductivity, which occurs when total nanowire mass approaches ~15% copper concentration

Peer Assessment of Class Participation: Applying Peer Nomination to Overcome Rating Inflation

Having students actively engaged with each other in discussions has become an increasingly important and common aspect of the classroom environment. This increased emphasis has also meant that instructors need to find ways to effectively and efficiently evaluate class participation. In this paper, we describe the most common method used for these assessments and highlight some of its inherent challenges. We then propose an alternative based on peer nominations. Two case studies illustrate the advantages of this method; we find that it is both easy for students to complete and provides instructors with valuable diagnostic information with which to provide feedback and assign grades

Auction Fever: The Effect of Opponents and Quasi-Endowment on Product Valuations

The wide adoption of dynamic second-price auctions as the format of choice for Internet-based (online) transactions has created an interest in understanding how individuals behave in such environments. The current work concentrates on two dynamic effects, which we call quasi-endowment and opponent effect, and finds that these effects may result in over-bidding. The results of two experimental auctions – one involving hypothetical bids and the other real-money bids – demonstrate that bids reflect valuations that include the non-normative influences of the two factors. Quasi-endowment and opponent effects could lead to the behaviors of repeated bidding and sniping commonly observed in second-price online auctions such as eBay

Mid-IR Excitation of Graphene

In this research we investigate how the conductivity of graphene changes in response to mid-infrared photoexcitation. Our p-type sample was formed through chemical vapor deposition. Pump/probe methodology produced the time-resolved Terahertz transmission, from which the photoconductivity was calculated. We probed the sample with energies above and below the Fermi energy, which was determined by Fourier transform infrared spectroscopy. Our results support a model in which heating of the electron gas, leading to high carrier scattering rates, is responsible for a decrease in conductivity. We observe this negative photoconductivity at all pump energies, allowing us to rule out the possibility of population inversion to explain the results

I Was Pleased a Moment Ago: How Pleasure Varies With Background and Foreground Reference Points

The pleasure of an outcome is often evaluated relative to salient reference points. In the background, increasing sequences of positive outcomes are more enjoy- able than decreasing sequences. In the foreground, outcomes that could have been worse are often more enjoyable than those that could have been better. How does pleasure vary when both background and foreground reference points are salient? Using a repeated gambling task in which participants make a choice, learn the outcome, watch their cumulative earnings change, and rate the pleasure of the out- come, we explore this question. Pleasure depends on background and foreground reference points, but the immediate events tend to dominate. The relatively narrow focus on the most recent reference points leads to myopic pleasure. We offer a modified version of decision affect theory to account for the results and explore the implications for consumer satisfaction

Effort for Payment

The standard model of labor is one in which individuals trade their time and energy in return for monetary rewards. Building on Fiske’s relational theory (1992), we propose that there are two types of markets that determine relationships between effort and payment: monetary and social. We hypothesize that monetary markets are highly sensitive to the magnitude of compensation, whereas social markets are not. This perspective can shed light on the well-established observation that people sometimes expend more effort in exchange for no payment (a social market) than they expend when they receive low payment (a monetary market). Three experiments support these ideas. The experimental evidence also demonstrates that mixed markets (markets that include aspects of both social and monetary markets) more closely resemble monetary than social markets

A respondent friendly method of ranking long lists

This article illustrates a respondent-friendly approach to preference elicitation over large choice sets, which overcomes limitations of rating, full-list ranking, conjoint and choice-based approaches. This approach, HLm, requires respondents to identify the top and bottom m items from an overall list. Across respondents, the number of times an item appears in participants’ L (low) list is subtracted from the number of times it appears in participants\u27 H (high) list. These net scores are then used to order the total list. We illustrate the approach in three experiments, demonstrating that it compares favourably to familiar methods, while being much less demanding on survey participants. Experiment 1 had participants alphabetise words, suggesting the HLm method is easier than full ranking but less accurate if m does not increase with increases in list length. The objective of experiment 2 was to order US states by population. In this domain, where knowledge was imperfect, HLm outperformed full ranking. Experiment 3 involved eliciting respondents’ personal tastes for fruit. HLm resulted in a final ranking that correlated highly with MaxDiff scaling. We argue that HLm is a viable method for obtaining aggregate order of preferences across large numbers of alternatives

Neural network identification of keystream generators

Applications such as stream ciphers and spread spectra require the generation of binary keystreams to implement, and the simulation of such keystreams to break. Most cryptanalytic attacks are of the known generator type, that is, they assume knowledge of the method used to generate the keystream. We show that a neural network can be used to identify the generator, and in some cases to simulate the keystream.http://archive.org/details/neuralnetworkide00leadApproved for public release; distribution is unlimited

High speed thin plate fatigue crack monitor

A device and method are provided which non-destructively detect crack length and crack geometry in thin metallic plates. A non-contacting vibration apparatus produces resonant vibrations without introducing extraneous noise. Resulting resonant vibration shifts in cracked plates are correlated to known crack length in plates with similar resonant vibration shifts. In addition, acoustic emissions of cracks at resonance frequencies are correlated to acoustic emissions from known crack geometries