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Search Results: 1 - 10 of 10672 matches for " x-rays. "
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Evaluation of the Effects of Irradiation of Peanut Grain by a Gamma-Ray Beam on Culture  [PDF]
G. Mbaye, M. Soumboundou, L. A. D. Diouf, B. Ndong, A. R. Djiboune, P. M. Sy, S. M. Dieng, M. Diouf, N. N. Diouf, A. Barry, M. Diarra
Open Journal of Biophysics (OJBIPHY) , 2017, DOI: 10.4236/ojbiphy.2017.73008
Abstract: The problems of agriculture in Senegal result in a low yield per hectare and poor seed quality contributing strongly to the decline in productivity. Mutagenesis by X- or Y-ray irradiation makes it possible to obtain genetic mutants necessary to improve production. It is in this context that we undertook this study to evaluate the effects induced on the cultivation of peanut seeds irradiated by X-rays at low doses applied in radiotherapy. X-ray irradiation of four (2, 3, 4, 5) lots of peanuts are performed with respectively 0.5, 1.5, 2 and 4 Gray using the cobalt 60 therapy device (Alcyon II). The seeding of the seeds and then the following-up of the crops during 35 days allowed us to study the parameters of germination, growth and yield. The results obtained after monitoring revealed that the irradiation did not have any significant impact on germination and would appear to temporarily inhibit the growth rate compared to the control batch. However, the decrease in weight of the harvested seeds can be explained by the absence of fertilizer during the cultivation.
Determination of Residuals Stresses Induced by the Autofrettage Treatment by the X-Rays Diffraction Method  [PDF]
Naziha Zerari, Tarik Saidouni, Abdelouaheb Benretem
Modern Mechanical Engineering (MME) , 2013, DOI: 10.4236/mme.2013.33017
Abstract:

Some meaningful advances have been made these last years to value precise and reliable way the residual stresses experimentally created by the autofrettage. The autofrettage process is used widely to introduce residual stresses into thick walled tubes; traditionally residual stresses have been measured using the Sachs method destructive or non-destructive methods. In this paper we describe the application of the X-rays diffraction; this technique permits to justify the presence of the compressive tangential residual stresses, and to value their distribution after two different autofrettage internal pressures loading. The results show that there is a large difference in the residual stresses find in the different autofrettege pressure. One can see the influence of the autofrettage’s pressure quantity on residual stresses created in the thickness of the test tubes.

Prospects of the Hard X-Ray Instrument POLAR to Measure Polarization of Solar Flares  [PDF]
W. Hajdas, T. W. Bao, T. Batsch, I. Britvitch, J. Y. Chai, Y. W. Dong, N. Gauvin, M. N. Kong, R. Kramert, C. Lechanoine-Leluc, Lu Li, J. T. Liu, X. Liu, R. Marcinkowski, S. Orsi, M. Panicca, M. Pohl, N. Produit, D. Rapin, A. Rutczynska, D. Rybka, H. L. Shi, J. C. Sun, J. Szabelski, I. Traceira, R. J. Wang, X. Wen, B. B. Wu, H. L. Xiao, H. H. Xu, Li Zhang, S. N. Zhang, Y. J. Zhang, A. Zwolinska
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.32040
Abstract:

In-depth studies of solar flares emissions and energy releases include analyses of polarization data. Polarization gives clear information about mechanisms and processes leading to electron acceleration and photon production. Despite of many past attempts, the key energy range of hard X-rays was only rarely explored and results were inconclusive. To large extend it was due to greater instrumental complications. Currently several novel polarimeters are either to be employed or under constructions for both balloon and satellite based observations. The novel hard X-ray polarimeter POLAR is an instrument developed by a collaboration between Switzerland, China and Poland. It is primarily designed for high accuracy polarization measurements from the prompt photon emissions of the gamma-ray bursts. The satellite orientation and instrument pointing direction make it also capable for precise measurements of polarization in solar flares. The instrument should fly in near future onboard of the Chinese Space Station TG2.

Scatter Radiation Dose Assessment in the Radiology Department of Cape Coast Teaching Hospital-Ghana  [PDF]
J. Owusu-Banahene, E. O. Darko, D. F. Charles, A. Maruf, I. Hanan, G. Amoako
Open Journal of Radiology (OJRad) , 2018, DOI: 10.4236/ojrad.2018.84033
Abstract: During the operation of an X-ray machine, if the radiation protection of X-ray room is insufficient, not only the patient but also clinical staffs as well as public are exposed to high X-ray exposures. In this research work, leakage and scattered radiations were measured from X-ray machine in the radiology department of Cape Coast Teaching hospital in the Cape Coast Municipality of Ghana. The scattered radiation exposures of X-rays in some selected areas within the facility were measured. The X-ray machine was operated for a range of kilo voltage peaks of kVp 77, 70, 63 and 66 with intensities 20, 6.3 and 8.0 mAs, which represents the main technique factors of some body parts such as chest, lumbar spine and extremities during radiographic examinations. The measurements were performed using a RADOS-120 Universal survey meter. The radiation doses rates measured in the various locations in the Radiology Department of Cape Coast Teaching Hospital of Ghana were in the range of 0.10 μSv/hr to 0.12 μSv/hr. These values were all within the background measurement of 0.10 μSv/hr. Moreover, there were no risks of high radiation doses to patients, staffs and people visiting the X-ray department. The results obtained indicated that within the radiology department of the Hospital, all the selected locations were very safe to patients, occupational workers and the general public which could be attributed to adequate shielding in the facility.
Raios-x: fascina??o, medo e ciência
Lima, Rodrigo da Silva;Afonso, Júlio Carlos;Pimentel, Luiz Cláudio Ferreira;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000100044
Abstract: this work presents the discovery and the use of x-rays at the end of the xixth and the beginning of the xxth century. x-rays greatly impacted science and everyday life. their existence broke the idea that knowledge had reached a limiting step. in general, people regarded x-rays as a marvel of science, but reactions against their use were also found. several applications were proposed, especially in medicine. however, little or no attention was paid to security measures, leading to health damages and even death. the development of the radiological protection took into account the accidents with the x-rays.
Description of the technique of upper gastrointestinal series radiological examination for the evaluation of the esophagus, stomach and duodenum of Wistar female rats
Grossi, Jo?o Vicente Machado;Nicola, Roberto Fernandes;Bigolin, André Vicente;Montes, Juliano Hermes Maeso;Lima, Juliano Nunes Chibiaque de;Kraemer, Raul;Cavazzola, LeandroTotti;
Acta Cirurgica Brasileira , 2009, DOI: 10.1590/S0102-86502009000600012
Abstract: purpose: to evaluate the anatomy of female wistar rats and the workability of contrast radiography as a technique to investigate the gastrointestinal series. methods: eight adult female wistar rats were undergone to the contrast radiography as anteroposterior incidence and as posterior incidence in profile. the radiological examination was conducted at a 45° angle to the radiological table. film-focus distance (ffd) was 100 cm, film-object distance (fod) was 0 cm, and object-focus distance (ofd) was 100 cm. an orogastric probe was used to inject barium contrast at 5-min intervals, for a total of four applications. after the radiological examination, animals were necropsy for confirmation of the radiological findings, and the radiographs were the absence of the normal anatomy variations inspected and described by an experienced radiologist. results: all the radiographs produced achieved satisfactory results in terms of position, exposure, location and quality. the upper esophageal sphincter (ues) was identified in the esophagus at the nerve c2, the lower esophageal sphincter (les) was identified between spinal cord segments l1 and l2, the thoracic-abdominal junction was observed at t10, the esophageal-gastric junction (egj) at t13-l1, with the abdominal portion in the epigastric region. the stomach was observed mostly in the epigastric region, left hypochondrium, left and mesogastric flank. the duodenum findings presented higher variation, with most findings identified in the epigastric region, right hypochondrium, right flank and mesogastric ileal fossa at t13-l5. conclusion: contrast radiology is useful and may be employed to assess the anatomy of the animal being studied. the experimental model described afforded to fully identify all organs investigated, as well as other occasional relevant findings. no anatomical anomalies in the subsequent necropsy, confirming the radiographic findings.
Selectivity and efficiency of pyrene attachment to alkanes induced by broadband X-rays
BROWN, GERALD O.;GUARDALA, NOEL A.;PRICE, JACK L.;WEISS, RICHARD G.;
Anais da Academia Brasileira de Ciências , 2003, DOI: 10.1590/S0001-37652003000100005
Abstract: bombardment of pyrene-doped n-heneicosane (c21h44) in its orthorhombic solid phase with <1.3> mev broadband x-rays results in the formation of both mono- and di-heneicosylpyrenes, whereas the same dose in liquid cyclohexane yields only monosubstituted pyrene. in both cases, the reaction efficiency decreases as pyrene concentration is increased from 10-5 to 10-2 m. qualitatively, the overall attachment efficiency is higher in orthorhombic n-heneicosane than in liquid cyclohexane, but the selectivity of attachment is greater in cyclohexane. differences between these results and those from irradiations of the same samples with ev range photons are discussed.
Exposi??o à radia??o ionizante na sala de hemodinamica
Medeiros, Rogério Fachel de;Sarmento-Leite, Rogério;Cardoso, Cristiano de Oliveira;Quadros, Alexandre Schaan de;Risso, Elvira;Fischer, Leandro;Gottschall, Carlos A. M.;
Revista Brasileira de Cardiologia Invasiva , 2010, DOI: 10.1590/S2179-83972010000300015
Abstract: background: with the technological evolution and expansion of interventional cardiology, the levels of x-ray exposure of patients and technical staff as well as the number of catheterization procedures have increased considerably. this has an impact on the inherent risk of exposure to ionizing radiation which is still underestimated by many. the levels of exposure must be routinely measured and adjusted. our objective was to investigate and measure ionizing radiation levels emitted by cath lab x-ray equipments. methods: technical tests were conducted to evaluate the air kerma of 8 x-ray equipments. results: only 2 (25%) of the 8 equipments had dosimetry within maximum safety levels. the mean dose was 65% higher in devices with the flat detector technology. after supervised maintenance, there was a mean decrease of 42% in dosimetry values. all equipments were approved by the high and low contrast spatial resolution tests, and the image quality was approved by the medical team. conclusions: most of the equipments evaluated had dosimetry levels exceeding the maximum safety levels, especially those with the flat detector technology. these distortions were corrected by simple monitoring measures, without losses in image quality. our results emphasizes the need to create institutional quality programs, to keep regular equipment maintenance and to exercise discretion in the incorporation of new technologies to minimize the potential effects of the deleterious effects of ionizing radiation, promoting greater safety and economy.
Elementary chemical analysis in leaves infected by fumagina by X-Ray fluorescence technique
Blonski, Maria Sélia;Appoloni, Carlos Roberto;Parreira, Paulo Sérgio;Arag?o, Pedro Henrique Arruda;Nascimento Filho, Virgilio Franco;
Brazilian Archives of Biology and Technology , 2007, DOI: 10.1590/S1516-89132007000500013
Abstract: energy dispersion x-ray fluorescence technique (edxrf) was employed to study the effects of the fumagina disease on the elementary chemical composition of the leaves. the experimental set up consisted of a mo x-ray tube (ksubμ = 17.44 kev) with zr filter and a si (li) detector. the measurements were performed with the infected and healthy leaves of citric plants. the elements ti, mn, fe, cu and zn were quantified, with an average dl of 69, 12, 8, 4 and 4 μg.g-1 respectively. the obtained concentration for fe varied from 44 to 192 μg.g-1 in healthy leaves and from 363 to 704 μg.g-1 in infected leaves with fumagina .
Avalia??o da densidade mineral óssea em potros da ra?a Puro Sangue Inglês em início de treinamento
Prado Filho, José Roberto Cintra do;Sterman, Franklin de Almeida;
Brazilian Journal of Veterinary Research and Animal Science , 2004, DOI: 10.1590/S1413-95962004000600005
Abstract: the radiographic optical densitometry (rod) is an analysis method for bone mineral content evaluation in equivalence to the aluminiun milimeters (mmai). bone densitometry was performed by a carpal acessory bone simple latero-medial radiograph conjugated with an aluminium stepwedge after complete calcification of growth plate of radial distal epifisis. two groups (divided by sexual category male/female) of 50 animals each were evaluated and all these 100 animals were under an initial trainning program during the experiment. radiographs were digitalized and analyzed by a specific software (imagelab, softium) responsible for bone densitometry final determination expressed in mmai. statistical analysis (instat) was performed on results for determination of normal curve of bone density by rod method.
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