74 research outputs found
Solution of heat transfer inverse problem in thin film irradiated by laser
[EN] The presented article deals with inverse problems in nanoscale heat transfer identification problems [1]. Heat flow in solids can be modelled using various models. When dealing with objects of small dimensions, of the order of nanometres, and with fast heating processes, comparable to relaxation times, then it is reasonable to use molecular dynamics or the Boltzmann transport equation (BTE) [2]. The presented coupled system of Boltzmann transport equations has the advantage over molecular dynamics that it has a less complicated mathematical apparatus and calculations proceed faster. A thin film irradiated by ultrashort laser pulse is modeled using BTE. Heat transfer parameters of the model are identified using evolutionary algorithm – an optimization algorithm inspired on biological evolution of species. Multicriterial identification is characterized as an optimization problem where the difference between obtained and expected results is minimized.The research is funded from the projects Silesian University of Technology, Faculty of Mechanical Engineering, 2021.Korczak, A.; Mucha, W. (2022). Solution of heat transfer inverse problem in thin film irradiated by laser. En Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València. 200-204. https://doi.org/10.4995/YIC2021.2021.12580OCS20020
ZASTOSOWANIE INTERWAŁOWEJ METODY SIATEK BOLTZMANNA DO NUMERYCZNEGO MODELOWANIA PROCESU NAŚWIETLANIA LASEREM PULSACYJNYM CIENKICH WARSTW METALOWYCH
In the paper the one-dimensional numerical modelling of heat transfer in thin metal films irradiated by ultra short laser pulses is considered. In the mathematical description the relaxation times and the boundary conditions for phonons and electrons are given as interval numbers. The problem formulated has been solved by means of the interval lattice Boltzmann method using the rules of directed interval arithmetic. The examples of numerical computations are presented in the final part of the paper.W artykule zaprezentowano jednowymiarowy model numeryczny przepływu ciepła w cienkich warstwach metalowych poddanych. naświetlaniu laserem pulsacyjnym. W opisie matematycznym czasy relaksacji oraz warunki brzegowe dla fononów i elektronów są zdefiniowane jako liczby przedziałowe. Sformułowane zagadnienie rozwiązano za pomocą interwałowej metody siatek Boltzmanna stosując skierowaną arytmetykę interwałową. W końcowej części artykułu przedstawione są przykłady obliczeń numerycznych
MODELOWANIE PRZEPŁYWU CIEPŁA W DWUWYMIAROWYM CIELE KRYSTALICZNYM ZA POMOCĄ INTERWAŁOWEJ METODY SIATEK BOLTZMANNA
In the paper the two-dimensional numerical modelling of heat transfer in crystalline solids is considered. In the mathematical description the relaxation time and the boundary conditions are given as interval numbers. The problem formulated has been solved by means of the interval lattice Boltzmann method using the rules of directed interval arithmetic.W artykule zaprezentowano dwuwymiarowy model numeryczny przepływu ciepła w ciele krystalicznym. W opisie matematycznym czas relaksacji i warunki brzegowe są zdefiniowane jako liczby przedziałowe. Sformułowane zagadnienie rozwiązano za pomocą interwałowej metody siatek Boltzmanna stosując skierowaną arytmetykę interwałową
Antarctic fur seal (Arctocephalus gazella) annual migration and temporal patterns of on-shore occurrence of leucistic individuals on King George Island.
Non-invasive tracking the on-shore occurrence of the atypically pigmented animals and determination of land residency duration of leucistic seals would help us find out more about the rotation of the migrating population. During seven austral summer seasons (2011–2018), by counting the animals every 10 days at the Cape Lions Rump shore, King George Island, South Shetlands, in the Antarctic Specially Protected Area No. 151 and the adjacent ice-free land (31.52 km2) we registered fourteen leucistic individuals per a total of 43,919 animals. Moreover, daily monitoring of local fauna resulted in further 33 leucistic animals (together 47, in all seasons). Whilst the results of 10-day censuses of the total population were similar inter-seasonally, a tendency for increased occurrence of leucistic individuals in successive seasons was revealed. Generally, the number of animals increased significantly as season progressed. Since leucistic individuals stayed on-shore for 1–2 days usually, it can be hypothesised that the observation of migrating Antarctic fur seals every 3 days does not involve the same individuals. Also, additional every 5-day censuses taken in one season in ASPA 151 resulted in a higher seasonal number of animals, which proves that more frequent counts help us estimate population abundance more efficiently. Thus, every 5-day counts are proposed as a feasible and justified method of population monitoring
Bases biológicas do cronotipo: análise da influencia do local, sexo, idade e frequencia do polimorfismo C3111T do gene hLock
Orientador: Fernando Mazzilli LouzadaMonografia (Bacharelado) - Universidade Federal do Paraná.Setor de Ciencias Biologicas. Curso de Graduaçao em Ciencias BiologicasResumo : A espécie humana caracteriza-se por ser diurna, concentrando os seus episódios de atividade durante o dia e de repouso durante a noite. O episódio de sono noturno, além de apresentar diferenças individuais em sua duração, não ocorre nas mesmas horas da noite em todos os indivíduos, ou seja, existem diferenças individuais relacionadas à preferência por horários de sono. Estas diferenças nos horários de sono estão associadas a diferenças de fase em outros ritmos biológicos, como o da temperatura corporal e da secreção de melatonina. Estas diferenças de fase existentes entre os indivíduos estão relacionadas ao chamado cronotipo. Inúmeros estudos mostram que o cronotipo é uma propriedade do sistema de temporização circadiana. Entretanto, ainda não se conhece a origem desta diferença. Ela poderia ter origem em diferenças presentes no relógio molecular de controle da ritmicidade circadiana. Os objetivos deste estudo foram analisar a influência do local, sexo e idade no cronotipo em adultos em relação à preferência diurna, através da utilização do questionário desenvolvido por HORNE e OSTBERG e verificar a freqüência do polimorfismo C3111T nos indivíduos extremamente matutinos e vespertinos com relação às preferências diurnas. 1.101 voluntários responderam ao questionário HO. Para a influência do local, sexo e idade no cronotipo foram analisados os dados dos voluntários adultos de duas localidades, São Paulo e Curitiba. A população de São Paulo apresentou uma pontuação mais elevada em relação à população de Curitiba. Os homens apresentariam uma tendência à vespertinidade. Para a verificação da freqüência do polimorfismo, a partir da pontuação obtida com o HO, foram selecionados os indivíduos extremos matutinos e vespertinos para que fosse feita a genotipagem a partir da extração de DNA. A análise de qui-quadrado não detectou diferenças significativas na freqüência dos alelos C e T entre matutinos e vespertinos. Nossos resultados sugerem que não existe associação entre o polimorfismo C3111T do gene Clock e o cronotipo
Influência dos sincronizadores sociais na expressão do ciclo vigília/sono em indivíduos com diferentes preferências diurnas
Orientador: Fernando LouzadaDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Biologia Celular e Molecular. Defesa: Curitiba, 2007Inclui bibliografia e anexosÁrea de concentração: FisiologiaExistem diferenças individuais na fase dos ritmos circadianos. Indivíduos com a
fase circadiana adiantada são chamados matutinos; aqueles com a fase
circadiana atrasada são chamados vespertinos. O questionário frequentemente
usado para acessar o cronotipo foi desenvolvido por Horne e Östberg (HO)
(HORNE e ÖSTBERG,1976). A pontuação do HO é influenciada por diversos
fatores, como o gênero, idade, latitude e hábitos sociais. Os objetivos deste
trabalho foram analisar o efeito das mudanças dos sincronizadores sociais sobre
as variáveis do ciclo vigília-sono de diferentes cronotipos e realizar a descrição de
voluntários classificados como indiferentes e que apresentam um padrão bimodal
de respostas ao questionário HO, denominados de bimodais. Os indivíduos foram
selecionados a partir da pontuação do HO. 8 matutinos, com idade média de
20,62(±2,77), 8 vespertinos, com idade média de 19,87(±1,36), 8 indiferentes com
idade média de 19,0(±1,41) e 6 bimodais, com idade média de 19,5(±2,07),
tiveram seus dados do ciclo vigília-sono obtidos a partir do uso do actimetro por
uma semana em duas ocasiões: aulas e férias. As médias do horário de início do
sono, horário de acordar, duração do sono e eficiência do sono foram comparadas
através da análise de variância (one-way ANOVA), separadamente, nas aulas e
nas férias, tendo como fator o cronotipo. Os dados de aulas e férias, para cada
variável, dentro de cada cronotipo, foram comparados através do teste de
Wilcoxon. A regularidade do sono foi analisada a partir da comparação das médias
dos coeficientes de variação de cada variável dependente nas duas situações,
aulas e férias. Os sujeitos matutinos são aqueles que dormem e acordam mais
cedo e têm a maior duração de sono. Os sujeitos vespertinos dormem e acordam
mais tarde e têm a menor duração do sono. Situações de maior imposição social
foram associadas a uma redução da duração total de sono, em situações de
menor imposição social as diferenças individuais na expressão do ciclo
vigília/sono manifestaram-se com maior clareza. Nas férias, os sujeitos bimodais
apresentaram um comportamento mais irregular, o que poderia sustentar a
hipótese de que esses sujeitos apresentariam maior plasticidade do ciclo vigíliasono.Inter-individual differences in the phase of the endogenous circadian rhythms has
been established. Individuals with a relatively early circadian phase are called
morning-types; those with a relatively late circadian phase are evening-types. The
most frequently used questionnaire to assess the individual chronotype is the one
developed by Horne and Östberg–HO (HORNE e ÖSTBERG,1976). The
distribution of HO scores is likely to be biased by several factors, such as gender,
age, latitude and social habits. The aim of this study were to analyze the effect of
changes of social synchronizers on the sleep wake-cycle of different chronotypes
and to describe classified volunteers like intermediate that showed a bimodal
standard of answers to questionnaire HO, called of bimodals. Individuals were
selected from HO scores. 8 morning-type, mean age 20,62(±2,77), 8 evening-type,
mean age 19,87(±1,36), 8 intermediate, mean age 19,0(±1,41) and bimodal, mean
age 19,5(±2,07), had their sleep schedules recorded by actigraphy for one week in
two occasions: schooldays (S) and vacations (V). Sleep onset, offset, duration and
efficiency for each chronotype group in each situation, schooldays and vacation,
were compared by means of a one-way ANOVA, considering chronotype as a
factor. Comparisons between schooldays and vacations were carried out by means
Wilcoxon matched pair test. Sleep regularity was compared by means of variation
coefficient. Morning-types was associated to earlier bedtime, earlier waking-up and
extended sleep duration. Eveningness was associated to later bedtime, later
waking-up time and a reduced sleep duration. The results support the idea that
social schedules have an impact on the expression of circadian rhythmicity and
reduces inter-individual differences. On vacations, bimodal subjects have a more
irregular sleep/wake patterns. The result could support the idea that those
subjects show bigger plasticity on the sleep wake-cycle
Modelling of transient heat transport in two-layered crystalline solid films using the interval lattice Boltzmann method
In the paper, the numerical modelling of heat transfer in one-dimensional crystalline solid films is considered. A generalized two-layer problem is described by the Boltzmann transport equations transformed in the phonon energy density equations supplemented by the adequate boundary-initial conditions. Such an approach in which the parameters appearing in the problem analysed are treated as the constant values is widely used, but in this paper the interval values of relaxation time and the boundary condition for silicon and diamond are taken into account. The problem formulated has been solved by means of the interval lattice Boltzmann method using the rules of directed interval arithmetic. In the final part of the paper the results of numerical computations are presented
An analysis of fungal propagules transported to the Henryk Arctowski Antarctic Station
During three austral summer seasons, dust and soil from clothes, boots and equipment of members of scientific expeditions and tourists visiting the Polish Antarctic Station Henryk Arctowski were collected and analysed for the presence of fungal propagules. Of a total of 60 samples, 554 colonies of fungi belonging to 19 genera were identified. Colonies of the genus Cladosporium, Penicillium and non−sporulating fungus (Mycelia sterilia) dominated in the examined samples. The microbiological assessment of air for the presence of fungi was also conducted at two points in the station building and two others outside the station. A total of 175 fungal colonies belonging to six genera were isolated. Colonies of the genus Penicillium were the commonest in the air samples. The potential epidemiological consequences for indigenous species as a result of unintentional transport of fungal propagules to the Antarctic biome are discussed in the light of rapid climate change in some parts of the Antarctic and adaptation of fungi to extreme conditions
Rapid environmental changes in the western antarctic peninsula region due to climate change and human activity
The Antarctic and the Southern Ocean are a critically important part of the Earth system. The climatic, physical, and biological properties of this region are closely linked to other parts of the global environment. 200 years of direct human impact, recent climate amelioration and changes in the main sources and circulation of biogenic compounds as well as accumulation of industrial contaminants have significantly affected the whole ecosystem. Particularly sensitive is the region of the Western Antarctic Peninsula, which is considered to be one of the hot spots of the Earth. In this paper, we review recent literature and compare it with historical data to estimate and predict the consequences of this process. The Antarctic ecosystems can no longer be regarded as pristine. Global as well as local human influence has transgressed the barriers isolating that continent from the rest of the World, causing previously observed changes to accelerate
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