Photochemical Charge Separation in Poly(3-hexylthiophene) (P3HT) Films Observed with Surface Photovoltage Spectroscopy

Surface photovoltage spectroscopy (SPS) was used to probe photon induced charge separation in thin films of regioregular and regiorandom poly(3-hexylthiophene) (P3HT) as a function of excitation energy. Both positive and negative photovoltage signals were observed under sub-band-gap (<2.0 eV) and super-band-gap (>2.0 eV) excitation of the polymer. The dependence of the spectra on substrate work function, thermal annealing, film thickness, and illumination intensity was investigated, allowing the identification of interface, charge transfer (CT), and band-gap states in the amorphous and crystalline regions of the polymer films. The ability to probe these states in polymer films will aid the development and optimization of organic electronic devices such as photovoltaics (OPVs), light-emitting diodes (OLEDs), and field effect transistors (OFETs). The direction and size of the observed photovoltage features can be explained using the depleted semiconductor model. © 2013 American Chemical Society

RE USE FUL

My terminal project is an exploration of reusing materials, developed in prototype and implemented into a practical scenario as part of an effort to limit waste in our society. Limit the amount of waste we produce by reusing materials rather than discarding them. I believe that the amount of waste we produce is a serious issue that must be addressed through creative reuses instead of larger landfills. I will utilize reused materials to create architectural components that can be adapted and inserted into any design solution. If we can gather materials in bulk that typically get discarded as waste, we can design new architectural components with them. With a clever and creative design approach these materials can be used to create attractive components that can either celebrate or conceal their original identity. Revitalize Cabrini Green with a new identity and logical master plan. As a case study to explore this approach I am using the Frances Cabrini Homes in south Cabrini Green, Chicago, IL. This is a low income residential community consisting of 54 two and three story buildings. This site has great potential; its surroundings are currently undergoing redevelopment, it’s structures are seeking renovation and it pleas for a new identity. What legitimizes this site is that the federal government determined that the brick and timber structures will receive minor renovation over the next several years. I will use the techniques discussed in the previous bullet to create new architecture and re-identify the Frances Cabrini Homes. This is a three phase project where the solution for one building will be the model for the others to follow. This exploration consists of a library of architectural elements, made of reusable-materials, developed in prototype, and implemented into an existing building shell

Effect of water environment on fatigue crack growth in low-alloy high-strength steel

Translated from Czech. (Kovove Mater. 1999 (3) p. 200-208)SIGLEAvailable from British Library Document Supply Centre-DSC:9023.190(VR-Trans-9263)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

A Kinetic Model for the Deterministic Prediction of Gel-Based Single-Chirality Single-Walled Carbon Nanotube Separation

We propose a kinetic model that describes the separation of single-chirality semiconducting carbon nanotubes based on the chirality-selective adsorption to specific hydrogels. Experimental elution profiles of the (7,3), (6,4), (6,5), (8,3), (8,6), (7,5), and (7,6) species are well described by an irreversible, first-order site association kinetic model with a single rate constant describing the adsorption of each SWNT to the immobile gel phase. Specifically, we find first-order binding rate constants for seven experimentally separated nanotubes normalized by the binding site molarity (<i>M</i>_θ): <i>k</i>_7,3 = 3.5 × 10^–5 M_θ^–1 s^–1, <i>k</i>_6,4 = 7.7 × 10^–8 M_θ^–1 s^–1, <i>k</i>_8,3 = 2.3 × 10^–9 M_θ^–1 s^–1, <i>k</i>_6,5 = 3.8 × 10^–9 M_θ^–1 s^–1, <i>k</i>_7,5 = 1.9 × 10^–11 M_θ^–1 s^–1, <i>k</i>_8,6 = 7.7 × 10^–12 M_θ^–1 s^–1, and <i>k</i>_7,6 = 3.8 × 10^–12 M_θ^–1 s^–1. These results, as well as additional control experiments, unambiguously identify the separation process as a selective adsorption. Unlike certain chromatographic processes with retention time dependence, this separation procedure can be scaled to arbitrarily large volumes, as we demonstrate. This study provides a foundation for both the mechanistic understanding of gel-based SWNT separation as well as the potential industrial-scale realization of single-chirality production of carbon nanotubes

A Framework for the Taxonomy of Synthesis and Analysis Activities in Distributed System Design

peer reviewe

Painometry: Wearable and objective quantification system for acute postoperative pain

Over 50 million people undergo surgeries each year in the United States, with over 70% of them filling opioid prescriptions within one week of the surgery. Due to the highly addictive nature of these opiates, a post-surgical window is a crucial time for pain management to ensure accurate prescription of opioids. Drug prescription nowadays relies primarily on self-reported pain levels to determine the frequency and dosage of pain drug. Patient pain self-reports are, however, influenced by subjective pain tolerance, memories of past painful episodes, current context, and the patient's integrity in reporting their pain level. Therefore, objective measures of pain are needed to better inform pain management. This paper explores a wearable system, named Painometry, which objectively quantifies users' pain perception based-on multiple physiological signals and facial expressions of pain. We propose a sensing technique, called sweep impedance profiling (SIP), to capture the movement of the facial muscle corrugator supercilii, one of the important physiological expressions of pain. We deploy SIP together with other biosignals, including electroencephalography (EEG), photoplethysmogram (PPG), and galvanic skin response (GSR) for pain quantification. From the anatomical and physiological correlations of pain with these signals, we designed Painometry, a multimodality sensing system, which can accurately quantify different levels of pain safely. We prototyped Painometry by building a custom hardware, firmware, and associated software. Our evaluations use the prototype on 23 subjects, which corresponds to 8832 data points from 276 minutes of an IRB-approved experimental pain-inducing protocol. Using leave-one-out cross-validation to estimate performance on unseen data shows 89.5% and 76.7% accuracy of quantification under 3 and 4 pain states, respectively