No description available.

Digitized by Kansas Correctional Industries / Department: Nuclear Engineering.

No description available.

Using a micro-potometric method, it was ,found that X-irradiation (400 R - 18 Kr) of the shoots of the onion plant Allium cepa will produce an immediate, pronounced (200%) and reversible enhancement of the water uptake by the shielded roots. Unfiltered X-irradiation.(1200 R/min., 120 KVP, 5 ma) was delivered at right angles to the shoot. Readings were taken at 10-minute intervals before, and immediately following X-irradiation. The greatest enhancement occurred at dosages between 4.8 Kr (150%) and 6.0 Kr (190%). The data indicate that the irradiation effect on water uptake was a physical rather than a metabolic one.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

No description available.

Σκοπός της παρούσης εργασίας είναι να παρουσιάσει τα ηλεκτρομαγνητικά, ηλεκτρικά και μαγνητικά πεδία που δέχεται ο άνθρωπος στην καθημερινότητά του, είτε αυτά παράγονται από φυσικές πηγές όπως είναι ο ήλιος, είτε από τεχνητές πηγές όπως είναι οι ηλεκτρικές συσκευές, η κινητή τηλεφωνία, το ηλεκτρικό δίκτυο κ.ά. Επίσης, παρουσιάζονται οι τρόποι υπολογισμού της έκθεσης του ανθρώπου στα πεδία αυτά και τα πιθανά προβλήματα που παρουσιάζονται στην υγεία του ανθρώπου εξαιτίας της έκθεσης. / Nowadays, human is continually exposed to electromagnetic fields, which are produced by nature or artificial sources which has discovered himself. However, the issue that troubles people is whether their health is affected by these fields or not. In this question have been trying to get answers the scientists, international and governmental organizations by carrying out measurements and scientific researches in order to define the impacts of electromagnetic fields on human’s health and determine the exposition limits to these fields. The target of this work is to present the electromagnetic, electric and magnetic fields which human receives in his daily routine, whether are produced by natural sources like sun or artificial sources like household appliances, mobile phones, electricity etc. Furthermore, are being displayed ways of estimation of human’s exposure to these fields and probable repercussions in human’s health owing to this exposure. In chapter two, there is an extensive reference to basic rudiments of fields and their main sources. In addition, are being defined typical magnitudes which are used in specification of electromagnetic fields and human’s exposure to these. In chapter three, are displayed the basic facts of ionizing radiation and its impacts on human. It is mostly presented the main source of ionizing radiation which is ultraviolet radiation of sun and problems which are produced. In chapter four, there is an extensive reference to fields which are produced by household appliances used in people’s houses and how are affect their health. 7 In chapter five, are being presented the basic facts of conveyance and distribution main of Γ.Δ.Ζ and at the same time are defined the impacts which the fields produce when they are near inhabitable areas. In chapter six, are mentioned the problems which can cause mobile phones and generally mobile telephony network which exists in the country through the fields which they produce. In chapter seven, there is a reference to the several types of radar which are used and their results. Whereas, in the next chapter there is a reference to the use of electromagnetic fields in medicine and are being presented radiation doses which we receive through examinations and other problems which can cause. Furthermore, are being presented the exposure limits which take effect in our country and European Union and also the way of analysis of exposure to multiple sources. In chapter eleven, there is a reference to macroscopic and microscopic analysis of exposure to electromagnetic fields. In the last chapter, there are being presented the ways of measurement of human’s exposure to electromagnetic fields with frequency up to 300 GHz.

No description available.

Orientador: Hugo Enrique Hernandez Figueroa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-05T08:31:54Z (GMT). No. of bitstreams: 1 Ambrosio_LeonardoAndre_M.pdf: 2415252 bytes, checksum: c4357386bcd33e0676d894544a47c85e (MD5) Previous issue date: 2005 / Resumo: Este trabalho apresenta um modelo numérico baseado no método das diferenças finitas no domínio do tempo, com objetivo de analisar as características da taxa de absorção específica, SAR, na cabeça humana, mediante um modelamento quiral das equações de Maxwell. A formulação é expressa em termos dos campos polarizados elétrico e magnético, permitindo investigar possíveis variações de SAR na cabeça humana, para diferentes valores de quiralidade, através de algoritmos simples. Tais algoritmos tornam possíveis a análise das diversas características da SAR em estruturas bidimensionais, representando secções transversais da cabeça humana, discretizada em seus tecidos de volumes significativos. Uma verificação foi feita calculando se a estabilidade numérica e simulando uma fonte pontual em um meio quiral. As influências da impedância equivalente da antena e da distância entre a antena e a cabeça humana foram investigadas, para diferentes valores quirais, bem como é feita a análise da SAR local média e sua variação percentual para os valores quirais escolhidos. Cinco cortes transversais foram analisados, com o objetivo de verificar características e comportamentos globais de SAR, evitando assim que variações locais fossem assumidas como um efeito global / Abstract: This work shows a numerical model based on the finite-difference time-domain method, with the aim of analysing the characteristics of the Specific Absorption Rate, SAR, in a human-head, through a quiral modeling of Mawell¿s equations. The formulation is expressed in terms of the electric and magnetic wave-fields, allowing to investigate possible changes in SAR, inside the human head, for different values of chirality, using simple algorithms. Such algorithms, make the analysis of the several characteristics of SAR in bidimensional structures representing the transversal layers of the human head, discretized in its tissues possessing significant volumes. A verification was made by calculating the numerical punctual stability and by simulating a punctual source in a chiral medium. The influences of the equivalent impedances of the antenna and of the distance between the antenna and the human head are analysed, for different chiral values, as well as an analysis of the average local SAR and its percentual variation for chosen chiral values. Five transversal layers were analysed, with the aim of verifying global characteristics and behaviors of SAR, avoiding that local variations were assumed as a global effect / Mestrado / Telecomunicações / Mestre em Engenharia Elétrica

<b><u>Introduction:</b></u> Some cancer survivors are known to have an elevated risk of morbidity and mortality from cardiovascular disease. An important cause of this elevated risk is recognised to be irradiation of normal tissues during radiotherapy received as part of cancer therapy. There are substantial difficulties in studying radiation-related cardiovascular disease (RRCD). The reasons for this include the complexities of measuring radiation normal tissue doses retrospectively and the prolonged latencies of many of the cardiovascular endpoints. A variety of complimentary research methodologies can help provide additional knowledge to guide the appropriate management of patients treated in the past and of new patients in the future. <b><u>Methods:</b></u> 1) A cohort study of mortality from circulatory disease in the nationwide British Childhood Cancer Survivor Study (BCCSS). 2) A case-control study of valvular heart disease (VHD) in Dutch Hodgkin lymphoma (HL) survivors, including retrospective radiation dosimetry to estimate the radiation dose to heart valves. 3) A dosimetric study of cardiovascular radiation doses in patients entered into the UK NCRI Lymphoma Study Group RAPID trial, including predictions of 15-year cardiac mortality using innovative methods. 4) A modelling study to predict mean whole heart dose (MWHD) from involved field radiotherapy (IFRT) for HL using anatomical measures. 5) A prospective study using cardiovascular magnetic resonance (CMR) imaging to characterise the heart in women receiving radiotherapy for breast cancer. <b><u>Results:</b></u> 1) The risks of all types of circulatory mortality are elevated in survivors of childhood cancer. The absolute excess risks continue to increase 40+ years following diagnosis. The risk of death from cardiomyopathy and heart failure increased substantially with the introduction of anthracycline chemotherapy. There is no evidence of a reduction in risk of circulatory mortality in more recent eras of diagnosis. 2) There is a strong relationship between estimated radiation dose to the affected heart valve and the risk of subsequent VHD (p<0.001). This effect was modelled to allow prediction of the risk of VHD. 3) A proportion of patients treated with IFRT received a substantial cardiac radiation dose (MWHD = 8.8 Gy, SD = 5.6) but, on average, the predicted 15-year cardiac mortality following treatment is low (absolute risk 0.2%, range 0.0 to 2.7%). 4) It is possible to estimate the mean whole heart dose from IFRT prior to detailed radiotherapy planning based on pre-treatment diagnostic imaging to an accuracy of 5-6% of the prescribed dose. 5) Although women received low cardiac doses (MWHD = 1.5 Gy, SD = 0.8) and have a low predicted risk of cardiac radiation-related morbidity and mortality, there is some evidence of subclinical effects on strain and strain rate imaging of the anterior portions of the left ventricle that receive the highest radiation dose. <b><u>Conclusions:</b></u> Using a variety of methods these studies have all succeeded in adding to knowledge about the nature, magnitude and timing of RRCD. This knowledge can be used to help the future management of cancer patients. In addition, each of the studies has natural and planned extensions and will continue to contribute further knowledge into the future.