Advances in solid polymer electrolyte fuel cell technology with low-platinum-loading electrodes

The Gemini Space program demonstrated the first major application of fuel cell systems. Solid polymer electrolyte fuel cells were used as auxiliary power sources in the spacecraft. There has been considerable progress in this technology since then, particularly with the substitution of Nafion for the polystyrene sulfonate membrane as the electrolyte. Until recently the performance was good only with high platinum loading (4 mg/sq cm) electrodes. Methods are presented to advance the technology by (1) use of low platinum loading (0.35 mg/sq cm) electrodes; (2) optimization of anode/membrane/cathode interfaces by hot pressing; (3) pressurization of reactant gases, which is most important when air is used as cathodic reactant; and (4) adequate humidification of reactant gases to overcome the water management problem. The high performance of the fuel cell with the low loading of platinum appears to be due to the extension of the three dimensional reaction zone by introduction of a proton conductor, Nafion. This was confirmed by cyclic voltammetry

Development of integrated thermionic circuits for high-temperature applications

Integrated thermionic circuits (ITC) capable of extended operation in ambient temperatures up to 500 C are studied. A set of practical design and performance equations is demonstrated. Experimental results are discussed in which both devices and simple circuits were successfully operated in 5000 C environments for extended periods. It is suggested that ITC's may become an important technology for high temperature instrumentation and control systems in geothermal and other high temperature environments

Preparation of Scanning Tunneling Microscopy Tips Using Pulsed Alternating Current Etching

An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:lr and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:lr tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHY-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:lr tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(l 11 )

WIRELESS IMPLANTABLE MAGNETOELASTIC SENSORS AND ACTUATORS FOR BIOMEDICAL APPLICATIONS

Magnetoelastic sensors represent a low-cost wireless and battery-less method for monitoring parameters in embedded or implanted applications; however, some limitations still exist preventing their commercial implementation. Presented in this work are a variety of studies that are aimed at improving the feasibility of magnetoelastic materials for sensing and actuating applications. Magnetoelastic resonant sensors of non-standard geometries were investigated to determine if geometry could play a role on the sensitivity of the sensor response to mass loading. It was shown that a significant increase in sensitivity could be achieved by using triangular sensors rather than standard rectangular strips. A method for monitoring multiple parameters on a single magnetoelastic resonant strip was also pursued. It was demonstrated that multiple parameters will have different effects depending on the location of the applied load due to the effect of sensor areas with zero vibration at different harmonics of the fundamental resonant frequency. Magneto-harmonic sensors and actuators were also explored in this work. Specifically, it was demonstrated that magnetoelastic sensors could be implemented as a means of detecting stresses on deep tissue wounds, which are critical for proper healing of certain wound sites after surgery. Both a suture and a suture anchor design were investigated for their efficacy at monitoring forces applied to tendon repair sites. Two detection devices were fabricated and built for this work which represent low-cost alternatives (both less than $200 each) to commercially available alternatives that minimally cost tens of thousands of dollars. This advancement reinforces the claim that magnetoelastic materials are a low-cost and portable sensing solution. The biodegradability and cytotoxicity of a promising magnetoelastic material for biomedical applications, specifically Galfenol (iron-gallium), was also investigated. Cytotoxicity tests demonstrated that concentrations much higher than would be likely to be encountered in vivo are necessary to cause significant cellular toxicity. Additionally, surface characterization of the degraded materials suggests that the degradation rate of Galfenol can be wirelessly controlled through application of externally applie

Staging Modernism

This thesis, which supports an exhibition of visual art, develops from Jean Baudrillard\u27s philosophy of seduction. I have focused on the representation of the bachelor and his pad in American men\u27s magazines from the mid-twentieth century. During this period, magazines such as Playboy, Escapade and Rogue created features on modern living to reassure an independent and affluent man that a dwelling with style and taste would ensure a happy bachelor life and facilitate intimacy. My photographs and collages add complexity to this portrait by framing this unique space as a stage where an unmarried man encircled by his lusty decor acted to entrance a woman

Relationship between Fungal Colonisation of the Respiratory Tract in Lung Transplant Recipients and Fungal Contamination of the Hospital Environment

International audienceBackgroundAspergillus colonisation is frequently reported after lung transplantation. The question of whether aspergillus colonisation is related to the hospital environment is crucial to prevention.MethodTo elucidate this question, a prospective study of aspergillus colonisation after lung transplantation, along with a mycological survey of the patient environment, was performed.ResultsForty-four consecutive patients were included from the day of lung transplantation and then examined weekly for aspergillus colonisation until hospital discharge. Environmental fungal contamination of each patient was followed weekly via air and surface sampling. Twelve patients (27%) had transient aspergillus colonisation, occurring 1–13 weeks after lung transplantation, without associated manifestation of aspergillosis. Responsible Aspergillus species were A. fumigatus (6), A. niger (3), A. sydowii (1), A. calidoustus (1) and Aspergillus sp. (1). In the environment, contamination by Penicillium and Aspergillus was predominant. Multivariate analysis showed a significant association between occurrence of aspergillus colonisation and fungal contamination of the patient’s room, either by Aspergillus spp. in the air or by A.fumigatus on the floor. Related clinical and environmental isolates were genotyped in 9 cases of aspergillus colonisation. For A. fumigatus (4 cases), two identical microsatellite profiles were found between clinical and environmental isolates collected on distant dates or locations. For other Aspergillus species, isolates were different in 2 cases; in 3 cases of aspergillus colonisation by A. sydowii, A. niger and A. calidoustus, similarity between clinical and environmental internal transcribed spacer and tubulin sequences was >99%.ConclusionTaken together, these results support the hypothesis of environmental risk of hospital acquisition of aspergillus colonisation in lung transplant recipients

Broadening the Role of Occupational Therapists within the ICU Setting: An Occupation-Based Toolkit

Purpose: The purpose of this project was to create a quick intervention toolkit for occupational therapists treating clients in the intensive care unit (ICU) in order to increase occupation-based services, quality of care, and improve client outcomes. Additionally, this project hopes to enlighten occupational therapists who may experience burnout while providing services within such an intensive setting

Evolution of Occupational Therapy Practice: Life History of Kuzhilethu “Shep” Kshepakaran, M. Ed., OTR/S, CAPS, FAOTA

The purpose of study is to provide current and future generations of occupational therapists a view of the history and how occupational therapy practice has evolved from its inception to current practice through the life history stories of occupational therapists who have held leadership roles at the national level and beyond. It is anticipated that the life history process will be a powerful way to gather this information. An in-depth interview with the selected participant, Kuzhilethu “Shep” Kshepakaran, as well as his resume and the internet were used to gather information. The categories created symbolized Shep’s life history which included personal experiences, perspectives and practice influence. The themes represented Shep’s personal values and beliefs, perspectives regarding practice and cultural awareness as well as commitment to the overall value of occupational therapy profession. The themes highlight the important aspects that led to Shep’s contributions to the OT profession regarding legislation as well as educational enhancement. By staying true to his personal motivations, Shep was able to use education and life experiences to accomplish various achievements which allowed him to increase his involvement in the field of occupational therapy as it grew and developed overtime.https://commons.und.edu/ot-oral-histories-posters/1084/thumbnail.jp