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das quebras negativas de relevo, como "e o.caso da unidade uAgr com a i. uAgn, e quando se estabelecem por falhamentos (caso da unidade uAgr com ...

International Nuclear Information System (INIS)

The properties of a new commercial thermoluminescent dosimeter, CaSO4:Dy without a LiF binder (TLD-900) was studied for low-exposure measurements in diagnostic radiology. The former TLD-900 had a LiF binder (herein referred to as ''TLD-900/LiF''). The principle features of this dosimeter are its high sensitivity to low-energy radiation and its relatively low fading which permits measurements down to less than 2.6 X 10(-8) C kg (0.1 mR) with an accuracy better than 20%. The characteristics, annealing procedures, light sensitivity, energy response, reproducibility, and fading, of TLD-900 are discussed and compared with TLD-900/LiF. When the precautions presented in this paper are used, the dosimeters can be used for the measurement of x-ray exposures.

Energy Technology Data Exchange (ETDEWEB)

The authors report the findings of Aicardi syndrome, a disease of unknown etiology composed of multiple spasms, chorioretinal lacunae and agenesis of the corpus callosum. They present a case of Aicardi syndrome with characteristic clinical presentation and magnetic resonance imaging findings. The disease, despite being considered rare, has characteristic imaging findings. Over the past years magnetic resonance imaging has improved its ability in demonstrating other findings besides agenesis of the corpus callosum, making the radiologist's role very important in the diagnostic suspicion of this disease. (author)

International Nuclear Information System (INIS)

A miniature device is described for measuring integral potential alpha energy concentration of radon daughter products (Csub(Rn)) for personnel and stationary dosimetry. The measuring apparatus consists of an air sampler, filters and TLD detectors. CaSO_4:Dy-teflon pellets were used as the detectors which registrate #gamma# radiation as well. The TLD-effect dependence on the potential alpha energy, as well as the fading of the detectors at 20-60 deg C after 170 hrs operation are presentd. The fading up to 40 deg C has been found to be negligible. The dosimeter may be used to measure Csub(Rh) starting with the 10"5 MeVxh/1 threshold, the accuracy being not worse than +-30%.

International Nuclear Information System (INIS)

A chemical-looping process is proposed for the clean combustion of solid fuels for electric power or heat generation. The process is based on coal gasification with CO_2 to produce CO. The CO then reduces CaSO_4, which is used as an oxygen carrier, in a separate reactor to give CaS and CO_2. A portion of the CO_2 is recycled for the gasification stage and the rest can be sent for sequestration. The CaS is sent to another reactor for oxidation with air and to generate heat or power. The overall thermal effect is the same as direct combustion, but separation of CO_2 and other pollutants, such as sulphur, is achieved. In comparison with conventional chemical-looping combustion of natural gas, much less water is present in the CO_2 product, and hence the loss of heat energy and corrosion of the fuel-reactor system can be reduced.

International Nuclear Information System (INIS)

Full text: Thermoluminescence (TL) is a phenomenon of light emission caused by heating a pre-irradiated material. When ionizing radiation hits a TL material, electrons are freed from some atoms and moved in the material, leaving behind 'holes' of positive charge. Subsequently when the TL material is heated, the electrons and the 'holes' re-combine, and release the extra energy in the form of light. The light intensity can be measured, and related to the amount of energy initially absorbed through exposure to the ionizing radiation. In nineteen sixties thermoluminescence dosimeters (TLD) became popular for dosimetric applications in view of their small size, sensitivity and accuracy. Consequently, in early seventies, several countries started adopting of TLD for personnel monitoring. The idea of introducing TLD to replace the then prevalent film dosimeter for personnel monitoring in India was mooted and successfully implemented by Dr. K G Vohra. Limitations of prevalent film dosimeters ...

Energy Technology Data Exchange (ETDEWEB)

A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass residue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass-to-ethanol facility using this softwood biomass was evaluated for two cases: Stand-alone and co-located. The co-located case refers to a specific site with an existing biomass power facility owned by Wheelabrator Environmental Systems Inc. near Martell, California. A two-stage dilute acid hydrolysis process is used for the production of ethanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, the co-located case is an economically attractive concept. Total estimated capital investment is approximately $ 70 million for the co-located case. The resulting internal rate of return is about 24% ...

Energy Technology Data Exchange (ETDEWEB)

The State of the Espirito Santo will become until the end of 2008, one of the main producers and natural gas exporters of Brazil, where, according to PETROBRAS, the State will produce about 20 million /day m{sup 3}, what it will go to contribute significantly for reduction of the dependence of the Bolivian gas, and still to give support to the natural gas sector in Brazil. The Intention of this work, is to identify proposals so that it has left of the gas produced in the State of the Espirito Santo, has a differentiated price. It does not make sensible the State to pay for the gas that is removed in its proper territory the same price that paid Sao Paulo for the gas that consumes imported of national Bolivia. With the markdown of the gas the State will be able to attract investments of great transport, to generate job and income and to advance in the question of the regional development that is of great importance for the developed cities less. Important to stand out that this study it ...

Energy Technology Data Exchange (ETDEWEB)

The paper investigates the functional endoscopic sinus surgery with the Messer-linger's technique which treats benign or inflammatory diseases of paranasal sinuses resistant to medical therapy. The goal of this type of surgery is to open the obstructed sinus ostia and restore normal aeration and mucociliary clearance. The computerized tomography permits an accurate assessment of extension and results of functional endoscopic sinus surgery. [Italian] L'articolo discute l'uso della tecnica di Messerklinger nella chirurgia funzionale endoscopica dei seni paranasali per il trattamento delle malattie benigne e delle infiammazioni croniche. Essa disostruisce gli osti sinusali ripristinando la normale areazione e la pulizia mucociliare. La tomografia computerizzata consente di valutare l'estensione e i risultati del trattamento chirurgico funzionale, soprattutto nel caso di insuccesso terapeutico, rilevando malattia nasosinusale ...

Energy Technology Data Exchange (ETDEWEB)

Purpose: To assess the role of CT in the evaluation of traumatic and spontaneous oesophageal perforation. Materials and methods: From March 2001 to May 2003, we studied 12 patients (7 males and 5 females; age range: 25-66 years, mean age: 43.5 years) with suspected oesophageal perforation due to motor-vehicle accidents (4 cases), stab wound (one case), post-intubation (2 cases), foreign body ingestion (2 cases) and spontaneous (3 cases). Five patients underwent standard chest and cervical radiography; two patients with suspected foreign body ingestion also underwent a gastrografin swallow study; all of the 12 patients underwent CT of the neck, chest and abdomen before and after intravenous, and in four cases oral, administration of contrast material. Results: In 5 patients with cervical, thoracic and abdominal trauma, the CT examination showed the presence of pleuroparenchymal injury (pneumothorax, pleural effusion and subcutaneous emphysema) as well as findings suggestive of ...

Energy Technology Data Exchange (ETDEWEB)

This document contains the technical proceedings of the 19 national seminar on the rational use of energy and exposition of equipment and services, organized by the Asociacion de Tecnicos y Pofesionistas en Aplicacion Energetica (ATPAE) (Association of Technicians and Professionals on Energy Application) conducted in Mexico City on September 21-25, 1998. This seminar encompassed subjects such as: energy saving in the energy sector, energy efficiency in industrial processes and practical developments, practical cases of energy saving in industry, energy saving in buildings, transportation, non-renewable energy utilization and environmental impact and eco-energies. [Espanol] Este documento contiene la memoria tecnica del 19 seminario nacional sobre el uso racional de la energia y exposicion de equipos y servicios, organizado por la Asociacion de Tecnicos y Profesionistas en Aplicacion Energetica (ATPAE), en Mexico, D.F, los dias 21-25 de septiembre de 1998. Este seminario trato de temas ...

Energy Technology Data Exchange (ETDEWEB)

Aim of this study was to evaluate the sensitivity of virtual colonoscopy (CT colonography) in the identification of colorectal cancer and to define the limitations and the advantages of this imaging modality, as well as indications to the examination. It was examined prospectively 62 symptomatic patients aged 36 to 82 years (28 women and 34 men). All patients underwent both conventional and virtual colonoscopy on the same day; the conventional examination allowed exploration of the entire colon. Conventional colonoscopy identified 89 lesions 3-50 mm in diameter, namely 84 benign and 5 malignant lesions. No lesions were identified in 12 patients. CT colonography identified 52 of the 89 lesions, with 57.1% diagnostic accuracy. They were 11 false positives (82.5% positive predictive value and 52.2% specificity) and 37 false negatives (24.5% negative predictive value and 58.4% sensitivity). Sensitivity was significantly higher (85.7%) for polyps {>=} 1 cm. Virtual colonoscopy is an ...

Energy Technology Data Exchange (ETDEWEB)

Penetrating liver wounds are related to many causes and rank second after blunt abdominal and liver trauma. In this report are examined the clinical and radiological findings of personal series of patients with penetrating trauma, especially by firearms and stab and cut wounds. It will also tried to define the diagnostic workup of these traumas, which is especially based on CT signs of liver damage and associated changes and which is of basic importance for following treatment, both surgical or conservative. In the last seven years it was retrospectively reviewed 31 cases of penetrating liver trauma. The patients were 19 men and 12 women, ranging in age 18 to 73 (mean 42), with penetrating liver injuries from firearms (16 patients) and stab (9 cases) wounds; 6 patients had injuries from different cases. Abdominal CT was carried out in emergency with the CT Angiography (CTA) technique in all patients. In the patients with suspected chest and abdomen involvement CT was performed from the ...