A Boltzmann model for rod alignment and schooling fish

We consider a Boltzmann model introduced by Bertin, Droz and Greegoire as a binary interaction model of the Vicsek alignment interaction. This model considers particles lying on the circle. Pairs of particles interact by trying to reach their mid-point (on the circle) up to some noise. We study the equilibria of this Boltzmann model and we rigorously show the existence of a pitchfork bifurcation when a parameter measuring the inverse of the noise intensity crosses a critical threshold. The analysis is carried over rigorously when there are only finitely many non-zero Fourier modes of the noise distribution. In this case, we can show that the critical exponent of the bifurcation is exactly 1/2. In the case of an infinite number of non-zero Fourier modes, a similar behavior can be formally obtained thanks to a method relying on integer partitions first proposed by Ben-Naim and Krapivsky.Comment: 22 pages, 3 figure

European round robin test on solar collectors and solar thermal systems

Within the European project QAiST (Quality Assurance in Solar Thermal Heating and Cooling Technology)a Round Robin test on solar collectors and solar thermal systems is carried out in the years 2010 and 2011. For two different collector types, one flat plate collector and one evacuated tubular collector with CPC reflector, thermal performance tests according to EN 12975-2 (EN 12975, 2006) are carried out by 12 different test institutes throughout Europe. The two different solar thermal systems, one thermosiphon system and one system with forced circulation are subject to a thermal performance test according to EN 12976-2 (EN 12976, 2006) and are tested by 9 different test institutes.In order to finish the Round Robin test within two years despite of the high number of participants, the following procedure was applied: Each participant received in the year 2010 samples of the two different collector types and of the two solar thermal system types respectively. After testing, the samples have been sent to the next test institute to be tested within the year 2011. Thus all institutes are testing identical collectors and system types taken out of the same production batch, however each unique collector or system is only tested by two institutes. For the first time Round Robin tests on solar thermal products are evaluated by an independent institute (Institut für Eignungsprüfung) using the acknowledged procedures for the evaluation of proficiency tests.This paper presents some of the midterm results of the Round Robin test in an anonymous and standardised way

Thermal comparison of glass furnace operation with oil and natural gas

Natural gas and fuel oil firing are compared for an industrial glass furnace by means of a three-dimensional computer simulation comprising sub-models for turbulence, combustion and thermal radiation. The heat transfer by thermal radiation from the flame and the furnace structure to the glass bath is discussed for both fuels. The total radiative heat flux to the glass is found to be 5 % higher for the case of the oil-fired furnace, while the distribution of heat flux to the glass was found to be less uniform. The heat flux intensities to the glass near the burner are much greater with oil flames because of their greater flame emissivities. But in the regions where combustion is complete heat transfer to the glass from the combustion gases is found to be more intense for natural gas. Comments are made on furnace ageing and pollution emission

Corporate social responsibility: the impact of employees’ perceptions on organizational citizenship behavior through organizational identification

The impact of the employees’ perceptions of CSR activities on the employee-organization relationship has been little explored in the literature. This study aims to analyze the impact of corporate social responsibility (CSR) perceptions (Environment-related CSR; Employee-related CSR, Customer-related CSR) on organizational citizenship behavior through the mediating role of the organizational identification of employees in the hotel sector. A questionnaire was applied to a sample of 214 frontline employees who work in four- and five-star hotels. Using Model 4 of the PROCESS macro, a mediation model was designed to test the hypotheses. The results indicate that there is a mediation model that uses the effect of organizational identification in the relationship between perceptions of CSR and organizational citizenship behavior. This study concludes that an increase in identification with the organization based on environmental-related activities, employee-related activities, or customer-related activities impact on OCB. The results of this study represent contributions to the literature in the CSR field, as well as to the case of human resources managers who wish to enhance organizational citizenship behavior and identification among hotel staff

Mulheres Licenciadas e a Promoção do Desenvolvimento em Angola: Que diferença faz o Ensino Superior?

A educação é um direito universal e uma ferramenta fundamental para o desenvolvimento das capacidades dos indivíduos e da sociedade. Em Angola, baixas taxas de qualificação da população estão associadas com as mais altas taxas de pobreza e exclusão social, desemprego, analfabetismo, mortalidade infantil, incidência de HIV, malária e tuberculose, entre outras. Níveis mais elevados de educação promovem maior bem-estar e qualidade de vida, por via dos rendimentos auferidos e, mulheres mais qualificadas terão tendência a melhorar o seu estatuto na sociedade e a modificar o seu estilo de vida. Por outro lado é expectável que motivem, de forma natural, à sua descendência a importância da aprendizagem e da aquisição de conhecimentos. Esta questão é particularmente pertinente em sociedades onde as mulheres desempenham um papel determinante na economia. Do ponto de vista da sustentabilidade dos territórios, podem contribuir ainda para a construção de uma sociedade mais sustentável. O presente trabalho tem como objectivo identificar a importância da obtenção de uma licenciatura na valorização social e económica das mulheres angolanas e, consequentemente na promoção do desenvolvimento da sociedade. Para tal, apresentam-se os resultados preliminares de um estudo exploratório de natureza qualitativa com base numa entrevista aplicada a uma amostra de conveniência de mulheres angolanas licenciadas. Os resultados permitem aferir a importância das mulheres licenciadas na promoção do desenvolvimento em Angola e sugerem tópicos para futuras pesquisas

Nutritional and phytochemical composition of Vaccinium padifolium Sm wild berries and radical scavenging activity

Blueberries have a well-deserved reputation as a potential functional food, supported by studies which have identified and quantified various nutrients and bioactive phytochemicals with known benefits for human diet and health. Wild blueberries have attracted particular attention due to the levels and concentrations of those phytonutrients. This study aims to evaluate for the first time the chemical composition of Madeira Island's endemic Vaccinium padifolium Sm wild berry. Results show that this fruit contains high values of total soluble phenolic content (around 4 g GAE kg-1 FW), as well as significant values of total monomeric anthocyanin content (around 3 g eq. cyanidin kg-1 FW) and DPPH scavenging activity (around 86.72%). Additionally, results reveal that this fruit has water content of about 88% as well as low sugar content (17.98 and 29.73 g kg-1 for glucose and fructose, respectively). Results also confirm that this wild blueberry is a good source of dietary fiber, fat and minerals. The high level of terpenoid compounds stands out in the aroma profile analysis.Ana C. Pereira acknowledges Agencia Regional para o Desenvolvimento da Investigação Tecnologia e Inovação (ARDITI) for financial support through her grant, M1420-09-5369-FSE- 000001.info:eu-repo/semantics/publishedVersio

Linguagem, cognição e argumentatividade: a construção de sentidos no modelo de espaços mentais

Enfoca os processos e operações subjacentes à produção de significados pela mente humana, à luz da Teoria da Integração Conceptual