A 1 GHz Oscillator-Type Active Antenna

Wireless sensors are desired for monitoring aircraft engines, automotive engines, industrial machinery, and many other applications. The most important requirement of sensors is that they do not interfere with the environment that they are monitoring. Therefore, wireless sensors must be small, which demands a high level of integration. Sensors that modulate an oscillator active antenna have advantages of small size, high level of integration, and lower packaging cost. Several types of oscillator active antennas have been reported. Ip et al. demonstrated a CPW line fed patch antenna with a feedback loop [1]. No degradation in performance was noticed without a ground plane. A GaAs FET was used in an amplifier/oscillator-based active antenna [2]. An oscillator based on a Cree SiC transistor was designed and characterized in [3]. This paper reports the integration of the SiC Clapp oscillator to a slotline loop antenna

Environments Past: Nostalgia in Environmental Policy and Governance

A variety of factors shape environmental policy & governance (EPG) processes, from perceptions of physical ecology and profit motives to social justice and landscape aesthetics concerns. Many scholars have examined the role of values in EPG, and demonstrated that attempts to incorporate (especially) nonmarket values into EPG are loaded with both practical and conceptual challenges. Nevertheless, it is clear that nonmarket values of all types play a crucial role in shaping EPG outcomes. In this paper, we explore the role of nostalgia as a factor in EPG. We examine literatures on environmental values, governance, and affect in light of their relationships to environmental policymaking, first as a means to decide whether or not nostalgia can be rightly described as an ‘environmental value.’ We suggest that, from a philosophical perspective, nostalgia is by itself environmentally neutral, and is not usefully described as a ‘value’. However, as an emotional state that longs to preserve or recover something of the past – whether fading or no longer present – that is fondly remembered, nostalgia does represent a potentially strong ‘motivator’ for EPG decisions. Despite this somewhat ambivalent assessment of nostalgia-as-environmental-value, we argue that nostalgia and nostalgic longing to return to the ‘better’ or ‘cleaner’ environments can lead to potentially significant impacts on ecosystems and landscapes, both positive and negative depending on what it is that people want to preserve or restore. Thus we conclude that we neglect understanding the role of nostalgia in EPG at our peril: first, because preservationist goals have always been an important part of environmental responsibility and second, because many people will be swayed regarding environmental action through a mobilization of nostalgia by political leaders and interest groups alike. We end our article with suggestion of avenues for further empirical investigation

Temperature Dependence of Thin Film Spiral Inductors on Alumina Over a Temperature Range of 25 to 475 C

In this paper, we present an analysis of inductors on an Alumina substrate over the temperature range of 25 to 475 C. Five sets of inductors, each set consisting of a 1.5, 2.5, 3.5, and a 4.5 turn inductor with different line width and spacing, were measured on a high temperature probe station from 10 MHz to 30 GHz. From these measured characteristics, it is shown that the inductance is nearly independent of temperature for low frequencies compared to the self resonant frequency, the parasitic capacitances are independent of temperature, and the resistance varies nearly linearly with temperature. These characteristics result in the self resonant frequency decreasing by only a few percent as the temperature is increased from 25 to 475 C, but the maximum quality factor decreases by a factor of 2 to 3. These observations based on measured data are confirmed through 2D simulations using Sonnet software

Caffeine and Sprint Performance in Habitual and Caffeine Naive Participants

Caffeine is thought to provide ergogenic benefits during endurance performance. However, there is limited research on the effects of caffeine on anaerobic sports performance. The purpose of this study was to examine the effects of 6 mg·kg-1 of caffeine on repeated sprint performance. The sample included active college students (N = 18), classified as habitual caffeine or caffeine naïve users. Participants completed a 12 x 30-m sprint test with 35 s rest intervals between sprints. Ratings of Perceived Exertion were collected every 3rd sprint. Height and body mass were measured and participants accommodated to the sprint test on Day 1. Participants were randomly assigned to the placebo or caffeine condition on Day 2 and the treatment was reversed on Day 3. Caffeine was ingested in a sports drink 1 h prior to performing the sprints. Caffeine produced a significantly faster best sprint time compared to the placebo trial, F (1, 17) = 7.38, MSE = .02, H-F p = .02. However, no significant difference was found between caffeine supplementation and placebo on time to complete the total sprint test. Additionally, no significant difference was found in sprint times with caffeine supplementation by sex or between caffeine-naïve and habitual caffeine users. Finally, a significantly higher average RPE was found with caffeine supplementation as compared to the placebo, t (1, 17) = 2.92, d = .38, p = .01. Caffeine has the potential to enhance sprint performance however, further research with women and habitual caffeine consumers is needed

High Temperature Characteristics of Coplanar Waveguide on R-Plane Sapphire and Alumina

This paper presents the characteristics of coplanar waveguide transmission lines on R-plane sapphire and alumina over the temperature range of 25 to 400 C and the frequency range of 45 MHz to 50 GHz. A Thru-Reflect-Line calibration technique and open circuited terminated stubs are used to extract the attenuation and effective permittivity. It is shown that the effective permittivity of the transmission lines and, therefore, the relative dielectric constant of the two substrates increase linearly with temperature. The attenuation of the coplanar waveguide varies linearly with temperature through 200 C, and increases at a greater rate above 200 C

Characteristics of Double Exponentially Tapered Slot Antenna (DETSA) Conformed in the Longitudinal Direction Around a Cylindrical Structure

The characteristics of a double exponentially tapered slot antenna (DETSA) as a function of the radius that the DETSA is conformed to in the longitudinal direction is presented. It is shown through measurements and simulations that the radiation pattern of the conformed antenna rotates in the direction through which the antenna is curved, and that diffraction affects the radiation pattern if the radius of curvature is too small or the frequency too high. The gain of the antenna degrades by only 1 dB if the radius of curvature is large and more than 2 dB for smaller radii. The main effect due to curving the antenna is an increased cross-polarization in the E-plane

Characteristics of Coplanar Waveguide on Sapphire for High Temperature Applications (25 to 400 degrees C)

This paper presents the characteristics of coplanar waveguide transmission lines fabricated on R-plane sapphire substrates as a function of temperature across the temperature range of 25 to 400 C. Effective permittivity and attenuation are measured on a high temperature probe station. Two techniques are used to obtain the transmission line characteristics, a Thru-Reflect-Line calibration technique that yields the propagation coefficient and resonant stubs. To a first order fit of the data, the effective permittivity and the attenuation increase linearly with temperature

Prosthetics in the Return to Trade Work

Importance: There is a lack of research on how different prosthetics impact return to work for individuals experiencing an upper extremity amputation. Objective: This review aims to assess myoelectric and body-powered prosthetics\u27 impact on return to physically demanding work and understand which is better suited for trade work demands and productivity. Data sources: Journal articles were last searched for using the databases, EBSCO, PubMed, Sage Journals and ScienceDirect, on October 13th, 2023. Study selection and data collection: Articles meeting inclusion criteria had to be peer-reviewed journal articles written in English, published in the last seven years, participants 18 years of age or older with an upper extremity amputation using a body-powered or external powered prosthetics, while hybrid prosthetics were not included for review. Findings: The systematic review includes four Level III articles and four Level IV articles, with four good, three fair, and one poor risk of bias ratings. Articles containing body-powered prosthetics reported less complaints and greater function in physically demanding work, while myoelectric prosthetics demonstrated greater dexterity and precise quick movements that impacted return to work. Conclusion and relevance: Myoelectric prosthetics are better suited for fine motor and mentally demanding work; however, body-powered prosthetics are better for gross motor and physically demanding work

Acute Effects of Static and Proprioceptive Neuromuscular Facilitation Stretching on Agility Performance in Elite Youth Soccer Players

Int J Exerc Sci 5(2) : 97-105, 2012. A warm-up is an important part of preparation for a soccer match. Stretching is typically part of the warm-up however, debate exists as to the most appropriate type of stretching to perform. The purpose of this study was to examine the effects of static and proprioceptive neuromuscular facilitation (PNF) stretching on soccer-specific agility performance in 14 male elite, premier league youth soccer players. Participants completed 4 trials of the Balsom agility test while dribbling a soccer ball. Height, age, and body mass were collected in trial 1 and participants were accommodated to the agility test during trials 1 and 2. Trials 3 and 4 were the static and PNF treatment trials that were administered after a standardized warm-up (control) in a randomized and counterbalanced manner. There were no significant differences between the difference scores of the static and PNF stretching conditions, P = .66. Furthermore, no significant differences were found between the control and stretching trials for static stretching, P = .15 or between the control and stretching trials for PNF stretching, P = .58. Neither mode of stretching significantly affected agility performance. More research is needed to determine the chronic effects of PNF stretching on agility performance

RF and DC Power Handling Characterization of Thin Film Resistors Embedded on LCP

For the first time, the DC and RF power handling capability of NiCrAlSi thin film resistors on Liquid Crystal Polymer (LCP) is presented. It is shown that there is a maximum power that the resistors can handle without causing degradation of the resistors, and this value is significantly less than the power required for burn out of the resistors. EDAX shows that the resistors fail due to electromigration of Ni and Cr, and migration of C from the LCP