Radiation-induced Electron and Hole Traps in Ge\u3csub\u3e1-x\u3c/sub\u3eSn\u3csub\u3ex\u3c/sub\u3e (x = 0-0.094)

The band structure of germanium changes significantly when alloyed with a few percent concentrations of tin, and while much work has been done to characterize and exploit these changes, the corresponding deep-level defect characteristics are largely unknown. In this paper, we investigate the dominant deep-level defects created by 2 MeV proton irradiation in Ge1 -xSnx (x = 0.0, 0.020, 0.053, 0.069, and 0.094) diodes and determine how the ionization energies of these defects change with tin concentrations. Deep-level transient spectroscopy measurements approximate the ionization energies associated with electron transitions to/from the valence band (hole traps) and conduction band (electron traps) in the intrinsic regions of p-i-n diode test structures. The prominent deep-level hole traps may be associated with divacancies, vacancy-tin complexes, and vacancy-phosphorous complexes (V2, V-Sn, and V-P, respectively), with the presumed V-P hole trap dominating after room temperature annealing. The ionization energy level of this trap (approximated by the apparent activation energy for hole emission) is close to the intrinsic Fermi level in the 0% and 2% Sn devices and decreases as the tin concentration is increased, maintaining an approximately fixed energy spacing below the indirect conduction band edge. The other hole traps follow this same trend, and the dominant electron trap ionization energies remain roughly constant with changes in tin concentrations, indicating they are likewise pinned to the conduction band edge. These results suggest a pattern that may, in many cases, apply more generally to deep-level defects in these alloys, including those present in the as-grown materials

System Design And Analysis Of A Renewable Energy Source Powered Microgrid

Today there is a great need for alternative new energy sources at cheaper development prices than those required from a traditional power plants. The renewable generation technologies are and will become both cheaper and more beneficial for our environment than other traditional means of productions. As Renewable Energy Generation technologies advance, it is important that Power Systems Engineers investigate carefully the Smart Grid and specially the Islanded Microgrid. Microgrid System Design Solutions that seek zero Emissions are more important as pollutants from traditional plants contribute to the contamination of the environment. In this thesis we use a Systems Engineering approach to design and analyze a typical Islanded Microgrid in order to seek zero emission Microgrids at the lowest possible cost. This study designs the Microgrid as a Smart Grid; we use and follow the design by considering engineering Standards from NIST and IEEE. Then we develop initial Microgrid System design and architecture. The System then is Analyzed and simulated in HOMER. Finally, a Tradeoff analysis is performed to search design variations and their effect on system cost as well as on environmental emissions

The mechanics of solid-state nanofoaming.

Solid-state nanofoaming experiments are conducted on two polymethyl methacrylate (PMMA) grades of markedly different molecular weight using CO2 as the blowing agent. The sensitivity of porosity to foaming time and foaming temperature is measured. Also, the microstructure of the PMMA nanofoams is characterized in terms of cell size and cell nucleation density. A one-dimensional numerical model is developed to predict the growth of spherical, gas-filled voids during the solid-state foaming process. Diffusion of CO2 within the PMMA matrix is sufficiently rapid for the concentration of CO2 to remain almost uniform spatially. The foaming model makes use of experimentally calibrated constitutive laws for the uniaxial stress versus strain response of the PMMA grades as a function of strain rate and temperature, and the effect of dissolved CO2 is accounted for by a shift in the glass transition temperature of the PMMA. The maximum achievable porosity is interpreted in terms of cell wall tearing and comparisons are made between the predictions of the model and nanofoaming measurements; it is deduced that the failure strain of the cell walls is sensitive to cell wall thickness

Do Products Respond to User Desires? A Case Study. Errors and Successes in the Design Process, under the Umbrella of Emotional Design

This article introduces a methodological approach to the evaluation of different industrial products according to Norman's approach and dimensions, focusing on a specific case study. The study also shows different possibilities to guide industrial designers during the design process in order to create products with high emotional value. For those, the case study was done with 330 target specific users, submitting nine prototypes (designed for different targets) to the user experience evaluation and product perception analysis. The evaluated proposals were selected from a total of 45. The results show the visceral, behavioural and reflective levels perceived by those users to whom each product is intended, as well as the target deviation within the design process. In this sense, the emotional response reveals the asymmetric character of perception according to Norman's dimensions

Executive functions and functional impairment in Latin seniors suffering from depression

Functional impairment (FI) relates to the condition of executive functions (EFs). While EFs become affected by age and educational level (EL). Seniors suffering from depression (SSDs) on the other hand show EF-related deficiencies; however, there is hardly any literature available regarding their relationship with FI in Latin SSDs, who usually have low ELs. Objective: To verify the relationship between EFs and FI in SSDs of Latin origins, by controlling the effects associated with age and educational level. Methodology: Cross-sectional study, of cases and controls, conducted on a nonprobability sample, made up of 102 self-sufficient SSDs and 142 control subjects over age 50, monolinguals of Latin origin (Chileans), all assessed by means of a battery of assessments such as: Geriatric Depression Scale, Addenbrook's Cognitive Assessment III, Trail making Tests A and B, STROOP word-color test, and semantic and phonological verbal fluency tests. A domain of composite EFs was established with standardized Chilean population scores, where age and educational levels were controlled. A simple linear regression analysis was conducted to determine the relationship between EFs and FI in SSDs. Results: Upon controlling age and educational levels, EFs explained an FI variance of 3.9% in SSDs; depression explained an EF variance of 3.2%, and 3.7% of FI. Conclusion: The results of the present study highlight the importance of a timely intervention when it comes to geriatric depression, considering the negative effect it has over the executive functions and the functionality of seniors

The impact of SARS-CoV-2 on emotional state among older adults in Latin America

In Latin America, the volume of care of infected patients, higher presence of comorbidities among older adults, and restricted access to clinical controls have become this age group into one with the highest risk (Dubey etal., 2020). Under confinement circumstances, older people can experience feelings of helplessness and uncertainty about the future, difficulties to stay focused, anxiety, stress, agitation, withdrawal, and depression (Armitage and Nellums, 2020; Wang etal., 2020). Accordingly, a Consortium of universities, research centers, and clinical centers have joined forces to carry out research which seeks to know the emotional state of Latin American older adults during confinement by Coronavirus disease (COVID-19). The study included the following countries: Argentina, Bolivia, Chile, Colombia, Costa Rica, Ecuador, Guatemala, Honduras, Mexico, Nicaragua, Peru, Puerto Rico, Dominican Republic, and Venezuela. Between April and May, we carry out the piloting of the evaluation protocol, making cultural and linguistic adaptations. Later, between June and October, more than 7000 older adults were evaluated by telephone by an expert professional through filling out an online form. The protocol we used includes a sociodemographic and clinical questionnaire, information on confinement, lifestyles, and the abbreviated version of the Yesavage Geriatric Depression Scale (Martínez de la Iglesia etal., 2020). Sociodemographic characteristics of the final sample (n = 5245) show that 34% are men and 66% are women, with an average age of 69.61 years (SD = 7.28). Average schooling was 10.99 years (SD = 5.85) depending on the country, and 16.7% were illiterate. The major racial pattern of the population is Latin American mestizo (55.1%) followed by white (39.4%), South American indigenous (1.5%), and African American subjects (1.2%). Seventy-seven percentage of the participants have a monthly income, from retirement (45.9%) or independent work (26.4%), and 85% live with their spouses or relatives. Regarding quarantine, 86.7% of the respondents stated that they complied with the confinement measures, with an average of 123.15 days (SD = 42.43) of quarantine, which varies by country. Our data analysis has revealed that 30.27% of the older adults exhibit emotional disturbances. In Mexico and Peru, we have observed the highest levels of geriatric depression (38.9% and 38.1%, respectively) and in Venezuela the lowest (21.35%). Regression analysis shows that more years of schooling (OR = 0.943; IC95%: 0.93–0.95), having an economic income (OR = 0.764; IC95%: 0.64–0.90) and being a Latin American mestizo (OR = 0.832, IC95%: 0.71–0.98) are associated with reduced risk of geriatric depression. On the other hand, being widowed (OR = 1.428; IC95%: 1.10–1.85) or separated (OR = 1.352; IC95%: 1.01–1.82), lived in Bolivia (OR = 1.805; IC95%: 1.31–2.48), Mexico (OR = 2.320; IC95%: 1.70–3.16), and Peru (OR = 2.008; IC95%: 1.45–2.78) are associated with highest risk. This first multicenter study found that emotional status of older adults during the SARS-CoV-2 pandemic in Latin America varies depending on the country where they live and sociodemographic and socioeconomic factors. It is necessary for follow-up studies to validate diagnosis and analyze the greater risk of deterioration in the coming months

Preferencia por el olor del etanol tras la interacción social con un congénere intoxicado en ratas adolescentes expuestas a la droga in-útero

Background: Prenatal exposure to ethanol and later socially mediated exposure predicts ethanol intake in human adolescents. Animal rat models indicate that brief interactions with an ethanol-intoxicated peer result in heightened preference for ethanol odor and ethanol intake. Methods: This study assessed preference for ethanol odor in adolescent male rats (observers) following social interaction with an ethanol intoxicated peer (demonstrators) as a function of prenatal ethanol exposure (gestational days 17-20, 1.0 g/kg, intragastric). Social behavior and locomotion during social interaction was also measured. Results: Social investigation was greater in observers that interacted with an intoxicated demonstrator in comparison to those that interacted with a sober peer. Social contact increased when the demonstrator was under the effects of ethanol, but only if the observer had experienced ethanol prenatally. Ethanol inhibited locomotion in the demonstrators. Finally, social interaction with an intoxicated peer during adolescence as well as prenatal ethanol experience increased preference for ethanol odor. Conclusions: Fetal exposure to ethanol mediated by maternal intoxication at late gestation or by interaction with an intoxicated peer at adolescence heightens preference for the chemosensory cues of the drug.Antecedentes: la exposición prenatal al alcohol y la exposición postnatal en contextos sociales predice el consumo de alcohol durante la adolescencia en humanos. Modelos animales indican que la interacción con un congéner intoxicado aumenta la preferencia por el olor del alcohol y su consumo. Método: se analizó la preferencia hacia el olor del etanol en ratas macho adolescentes (observadores) que interactuaron con un compañero intoxicado con alcohol (demostrador), en función de la exposición prenatal al alcohol (días gestacionales 17-20, 1,0 g/kg, intragástrica). Durante la interacción social, se evaluó la conducta social y la locomoción. Resultados: la investigación social fue mayor en los observadores que interactuaron con un sujeto intoxicado en comparación con aquellos que interactuaron con un sujeto sobrio. El contacto social aumentó cuando el demostrador estaba intoxicado, solo si el observador había sido expuesto al alcohol prenatalmente. El alcohol inhibió la locomoción en los demostradores. Finalmente, tanto la interacción social con un congéner intoxicado como la exposición prenatal incrementaron la preferencia por el olor a etanol. Conclusiones: el contacto con etanol durante la vida fetal, así como mediante la exposición a un par intoxicado durante la adolescencia, incrementa la preferencia por las claves quimiosensoriales de la droga.Fil: March, Samanta Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Pautassi, Ricardo Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Nizhnikov, Michael. University Of Binghamton; Estados UnidosFil: Fernandez Vidal, Juan Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; ArgentinaFil: Spear, Norman E.. University Of Binghamton; Estados UnidosFil: Molina, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones Médicas Mercedes y Martín Ferreyra; Argentina. Universidad Nacional de Córdoba; Argentin