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1

Modalidade de morte em mamiferos expostos a irradiacao de corpo inteiro (sindrome aguda da radiacao). (Modes of death in mammals exposed to whole body radiation (acute radiation syndromes)).  

Science.gov (United States)

When an animal is exposed to a sufficient amount of radiation, there will be changes in many organs of the body, and as a result of either the effects in one particular organ or the interaction of effects in several organs, the animal as a whole will show...

1990-01-01

2

Analysis of medicinal plant extracts by neutron activation method; Analise de extratos de plantas medicinais pelo metodo de ativacao com neutrons  

Energy Technology Data Exchange (ETDEWEB)

This dissertation has presented the results from analysis of medicinal plant extracts using neutron activation method. Instrumental neutron activation analysis was applied to the determination of the elements Al, Br, Ca, Ce, Cl, Cr, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sb, Sc and Zn in medicinal extracts obtained from Achyrolcline satureoides DC, Casearia sylvestris, Centella asiatica, Citrus aurantium L., Solano lycocarpum, Solidago microglossa, Stryphnondedron barbatiman and Zingiber officinale R. plants. The elements Hg and Se were determined using radiochemical separation by means of retention of Se in HMD inorganic exchanger and solvent extraction of Hg by bismuth diethyl-dithiocarbamate solution. Precision and accuracy of the results have been evaluated by analysing reference materials. The therapeutic action of some elements found in plant extracts analyzed was briefly discussed 70 refs., 13 figs., 15 tabs

1995-12-31

3

An efficient method for 3-D pre stack migration in time reverse-time depth by using finite difference method; Um metodo eficiente para migracao pre-empilhamento 3-D em profundidade reversa no tempo pelo metodo das diferencas finitas  

Energy Technology Data Exchange (ETDEWEB)

Much of the current technology on 3D-prestack depth migration is based on the Kirchhoff method and the traveltime information needed for this purpose is obtained by the ray-theory approximation. The main motivation driving these options is to reduce computations but it can also have an adverse effect on the quality of results. Experience with real data indicates that the corresponding poststack data migrated by the reverse-time method often yields superior results. Considerable computational efficiency can be obtained by employing nonuniform coarse grid spacing during the reverse-time migration. We followed this strategy for developing a parallel scheme for doing 3D- prestack depth migration. However, we worked only on a small subset of shot gathers whose determined by the Quasi-Monte Carlo method. The results were indistinguishable from those obtained by using a much larger population of uniformly spaced shot gathers. We present examples of migration of 3-D data. (author)

1997-07-01

4

Role of Spiral and Multislice Computed Tomography in the evaluation of traumatic and spontaneous oesophageal perforation. Our experience; Ruolo della Tomografia Computerizzata Spirale e Multistrato nello studio delle lesioni traumatiche e spontanee dell'esofago: nostra esperienza  

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 ...

2005-03-01

5

Analysis of coupled neutron-gamma radiations, applied to shieldings in multigroup albedo method; Analise das radiacoes neutron e gama acopladas, aplicada a blindagem com varias camadas pelo metodo multigrupo do albedo  

Energy Technology Data Exchange (ETDEWEB)

The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The radiation balance resulting from the incidence of a neutronic stream into a shielding composed by ...

2002-07-01

6

Study of the mineral variation of two varieties of pigeonpea (Cajanus cajan (L.) Millsp) submitted to different doses of fertilizers by the neutron activation analysis; Acompanhamento da variacao mineral de duas cultivares de guandu (Cajanus cajan (L.) Millsp) submetidas a diferentes doses de fertilizantes, pelo metodo de analise por ativacao com neutrons  

Energy Technology Data Exchange (ETDEWEB)

Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was used to determine the concentrations of As, Ca, Co, Cr, Cu, Eu, Fe, K, La, Mg, Mn, Mo, Na, Pr, Sb, Se, Th, U, V and Z, in 82 leaf samples belonging to two cultivars of pigeonpea (Cajanus cajan (L.) Millsp). Pigeonpea, an easy cultivation legume species, probably originated from Africa and adapted to brazilian conditions, is a very promising and unconventional source of food, mainly to the grain production intended for human feeding, and that even can be used in flour products. It is an excellent proteic supplement for ruminants, due to its large potential of forage production and its high nutritive value, or in addition it can be used in the recuperation of exhausting soils either by means of its utilization as green manure or by taking free Nitrogen from the atmosphere to produce nitrates which can be utilized by the plants. However, in spite of the several possibilities and increasing utilization ...

2001-07-01

7

The correlation between accelerated and field corrosion tests performed in carbon steel and weathering steel coupons, coated and non-coated; Correlacao entre ensaios acelerados e ensaios de campo em corpos-de-provas de aco carbono e aco patinavel, sem e com revestimento  

Energy Technology Data Exchange (ETDEWEB)

The performance of four different organic coating systems applied to carbon and weathering steel coupons has been assessed in this investigation. applied on the surface of carbon steel and weathering steel coupons. The coupons have been evaluated using five different tests, three field tests and two accelerated tests. The field tests were carried out at three atmospheric stations, located at COSIPA in Cubatao-SP, at Alto da Serra in Cubatao-SP and at Paula Souza in Sao Paulo city. The accelerated tests consisted of (a) exposure to alternate cycles of ultraviolet radiation/condensation combined with salt spray cycles (UVCON combined with Salt Spray) and of (b) exposure to alternate cycles of ultraviolet radiation/condensation combined with the Prohesion test. The performance of the coatings was assessed by visual observation and photographs, using a method based on ASTM D-610, ASTM D-714 and ASTM-1654 standards to rank them. The oxide phases formed on the surfaces of the non-coated ...

2002-07-01