Low power arcjet performance

An experimental investigation was performed to evaluate arc jet operation at low power. A standard, 1 kW, constricted arc jet was run using nozzles with three different constrictor diameters. Each nozzle was run over a range of current and mass flow rates to explore stability and performance in the low power engine. A standard pulse-width modulated power processor was modified to accommodate the high operating voltages required under certain conditions. Stable, reliable operation at power levels below 0.5 kW was obtained at efficiencies between 30 and 40 percent. The operating range was found to be somewhat dependent on constrictor geometry at low mass flow rates. Quasi-periodic voltage fluctuations were observed at the low power end of the operating envelope, The nozzle insert geometry was found to have little effect on the performance of the device. The observed performance levels show that specific impulse levels above 350 seconds can be obtained at the 0.5 kW power level

Scintigraphic Demonstration of Urine Extravasation Secondary to Acute Ureteral Obstruction: A Case Report and Some Considerations about Acute Ureteral Obstruction

Acute ureteral obstruction produces renal damage and complications that are proportional to the severity and length of the obstruction. Anatomic diagnosis of the obstruction may be insufficient to manage the patient. Intravenous urogram (IVU) is the method usually advised by radiologists to obtain functional information, but requires iodinated contrast agents. IVU anatomic information is superior to anatomic information obtained with renal scintigraphy, but normally the physician already has the anatomic information (unenhanced CT or ultrasound). A renal scan offers better physiologic information than the IVU, has neither adverse effects nor complications, is accurate to confirm or discard significant ureteral obstruction, and depicts obstruction complications. This paper presents a patient with spontaneous urine extravasation secondary to acute renal obstruction who is diagnosed with renal scintigraphy. The authors describe the scintigraphic signs of extraperitoneal, diffuse perinephric, urine extravasation and emphasize the role of renal scintigraphy in diagnosis and follow-up of renal colic

Antibiotic Prescribing Practices of Filipino Dentists

There are reports that dentists overprescribe antibiotics which may contribute to antibiotic resistance. This is an exploratory study on antibiotic prescribing practices of Filipino dentists using an online platform to form a basis for antimicrobial stewardship policy for dentists. A link to an online questionnaire using Survey Monkey was posted in a Closed Group Facebook account of Filipino dentists. Two hundred thirty (230) dentists participated. Data was analyzed by Survey Monkey. Amoxicillin is the first choice of antibiotics(71.18%), andclindamycin is the second (57.27%). Most respondents follow the indications for antibiotic therapy, however, some will prescribe antibiotics for conditions without indications. For dental procedures, 88.99% will prescribe for periodontal surgery, 75.45% for endodontic surgery, 68.3% for extraction of a tooth with chronic infection, 87.17% for third molar surgery, 26.7% for routine endodontics, and 23.56% for periodontal treatment without surgery. Not all of the respondents would prescribe for medical conditions that require antibiotic prophylaxis, while 60.36% will prescribe when in doubt in diagnosis, under time pressure (25.68%), and 48.67% considers patient preference. Only 10.48% of the respondents are very familiar with antimicrobial stewardship, while majority (69.74%) have not attended a lecture for antimicrobial stewardship for dentists.There is inappropriate antibiotic prescribing of participants on certain dental diseases, procedures, and medical conditions. Most respondents are not very familiar and have not attended a lecture on antimicrobial stewardship for specifically for dentists

Towards a Semantic Gas Source Localization under Uncertainty

Towards a Semantic Gas Source Localization under Uncertainty.Communications in Computer and Information Science book series (CCIS, volume 855), doi:10.1007/978-3-319-91479-4_42This work addresses the problem of efficiently and coherently locating a gas source in a domestic environment with a mobile robot, meaning efficiently the coverage of the shortest distance as possible and coherently the consideration of different gas sources explaining the gas presence. The main contribution is the exploitation, for the first time, of semantic relationships between the gases detected and the objects present in the environment to face this challenging issue. Our proposal also takes into account both the uncertainty inherent in the gas classification and object recognition processes. These uncertainties are combined through a probabilistic Bayesian framework to provide a priority-ordered list of (previously observed) objects to check. Moreover the proximity of the different candidates to the current robot location is also considered by a cost function, which output is used for planning the robot inspection path. We have conducted an initial demonstration of the suitability of our gas source localization approach by simulating this task within domestic environments for a variable number of objects, and comparing it with an greedy approach.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Características del suministro de leña al mercado energético doméstico en la ciudad de Santiago del Estero, Argentina

Casi la mitad de la población de la provincia de Santiago del Estero, Argentina, emplea la leña como combustible para cubrir sus necesidades energéticas tanto para el consumo doméstico familiar como para la producción a escala artesanal de alimentos destinados a la venta. Este trabajo analiza el uso intensivo de recursos forestales escasos en el ámbito doméstico, así como el desconocimiento de formas alternativas generadoras de energía y la falta de previsión para asegurarse la provisión de los mismos. El objetivo de esta investigación es caracterizar el modo de transacción y sus mecanismos referidos a la leña en el mercado local describiendo el modo de pago más empleado, así como los medios de transporte, el origen de la leña, y una breve caracterización de las tendencias acerca del recurso y la actitud de cambio de actividad productiva ante la escasez del mismo. La metodología se basó en el empleo de encuestas semi-estructuradas a consumidores de leña para uso productivo artesanal de comidas y alimentos típicos de la ciudad. Las encuestas contenían preguntas acerca de la cantidad de leña consumida en la producción de alimentos, el medio de pago, el origen de la leña y la forma de traslado de la misma. Los resultados revelan tres niveles de consumidores según el peso de leña consumida. Se detectó la presencia de un sistema de comercialización no formal manejado con vehículos motorizados. Casi toda la leña consumida es comprada y las transacciones son todas del modo contado efectivo.___________________________________Almost half of the population of Santiago del Estero, Argentina, uses firewood as fuel to meet their energy needs for both family consumption and sale-oriented production of food and meals at a craft level. This work analyses the intensive use of scarce forest resources within the domestic environment, the ignorance about energy-generating alternative forms as well as the lack of forecast for assuring their supply. The aim of this research is to characterize the way and the mechanisms by which firewood is commercialized locally, describing the most used ways of payment, transportation, firewood origin and including a brief characterization of the trends as to the resource and the attitude towards changing the productive activity to face its scarcity. Methodologically, semi-structured surveys were conducted among those using firewood for a craft production of typical food and meals. The surveys included questions concerning the quantity of firewood employed in preparing foods, its origin, and the ways it is hauled and paid. The results reveal three different levels of consumers according to the firewood they employ and detect the existence of a non-formal system of commercialization run by motorized vehicles. Both the purchase of almost all firewood consumed and transactions are made in cash

Población y Desarrollo: Objeto de reflexión Bioética

Según el último informe de Naciones Unidas sobre población mundial, se estima que la población aumentará hasta 9.3 mil millones en 2050 y a 10.1 mil millones en 2100.1 Tal crecimiento, que pudiera parecer exagerado, no lo es por muchas razones, especialmente si se mira la trasformación que ha vivido el globo en los últimos 30 años en relación con la tasa de fecundidad