Simulation of the effect of shading on monocrystalline solar module technology under hot spot condition

This paper focuses on the monocrystalline PV module technology subjected to operation conditions with some cells partially or fully shaded. A shaded cell under hot-spot condition operating at reverse bias are dissipating power instead of delivering power. A thermal model allows analyzing the temperature increase of the shaded cells of the module under hot-spot condition with or without protection by a bypass diode. A comparison of the simulation results for a monocrystalline PV module without shading and with partial or full shading is presented

Crystalline Silicon PV Module under Effect of Shading Simulation of the Hot-Spot Condition

This paper centers on the silicon crystalline PV module technology subjected to operation conditions with some cells partially or fully shaded. A shaded cell under hot-spot condition operating at reverse bias are dissipating power instead of delivering power. A thermal model allows analyzing the temperature increase of the shaded cells of the module under hot-spot condition with or without protection by a bypass diode. A comparison of the simulation results for a crystalline PV module without shading and with partial or full shading is presented

Qualidade superficial de componentes de móveis utilizando serra fita e fresadora e duas espécies

This study is dedicated to considering the use of eucalyptus and Ocotea porosa to produce classic-style furniture, assessing the machining time and surface quality. For such, the survey of data on the surface quality of eucalyptus and Ocotea porosa pieces was carried out through a visual assessment with the adaptation of the methodology described in standard ASTM 1666. This analysis of the wood surface quality occurred using two different species and two machining modalities (a band saw and a copy milling machine) for parts intended to produce components (feet) for classic furniture. After making the feet, the pieces of furniture were assembled and reassessed. Forty samples were selected and evaluated for initial defects through visual inspection, and the non-parametric Kruskal-Wallis statistical test was applied. The values found for surface quality were considered good quality, with more time being necessary to perform the finishing of the parts processed with the band saw than the milling machine. One may conclude that the milling time spent on each treatment influences the production capacity of the company, with the cuts carried out with the milling machine being faster and with better surface finishing.Esse estudo dedicou-se a considerar a utilização de eucalipto e Ocotea porosa na produção de móveis em estilo clássico, avaliando o tempo de usinagem e a qualidade superficial. Para tal, foi realizado o levantamento de dados sobre a qualidade superficial de peças de eucalipto e Ocotea porosa, por meio de uma avaliação visual com adaptação da metodologia descrita na norma ASTM 1666. Essa análise da qualidade superficial da madeira ocorreu por meio de duas diferentes espécies e conduzido por duas modalidades de usinagem (uma serra-fita e uma fresadora copiadora) de peças destinadas a produção de componentes (pés) para móveis clássicos. Após a confecção dos pés os móveis foram montados e novamente avaliados. Selecionou-se 40 amostras, nas quais foram avaliados os defeitos iniciais por meio da inspeção visual, foi aplicada a estatística não paramétrica de Kruskal-Wallis. Os valores encontrados sobre a qualidade de superfície foram considerados de boa qualidade, sendo necessário maior tempo para realizar o acabamento nas peças processadas na serra-fita se comparado com a fresadora. Pôde-se concluir que o tempo de usinagem gasto em cada tratamento influencia na capacidade de produção da empresa, sendo mais rápidos os cortes realizados pela fresadora com melhor acabamento superficial

Tratamento preventivo na melhoria da qualidade de madeira serrada de Pinus taeda L. em secagem natural

Sem resum

Estudo da qualidade da madeira serrada de três espécies de eucalipto

Orientador : Prof. Dr. Márcio Pereira da RochaTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Engenharia Florestal. Defesa: Curitiba, 01/11/2013Inclui referênciasÁrea de concentração : Tecnologia e utilização de produtos florestaisResumo: O objetivo dessa pesquisa foi contribuir com o conhecimento do desdobro de três espécies de Eucalyptus, E. dunnii, E. saligna, e E. grandis. Para atingir esse objetivo foi analisada a influência do diâmetro e do clone sobre a massa específica básica, a qualidade do material serrado, o rendimento em madeira serrada, e a deformação longitudinal residual, DRL. Também foram construídas correlações lineares sobre as características. Para isso, o delineamento utilizado foi em fatorial duplo associando espécie e diâmetro, e espécie e clone. Foram coletadas 75 toras de três espécies de Eucalyptus, divididas em 25 toras para cada espécie, 3 classes diamétricas e 15 clones. Foram mensurados o rendimento em madeira serrada, a variação das dimensões das peças serradas, os índices de encurvamento; arqueamento; e rachaduras, a DRL, o diâmetro a altura do peito (DAP), a altura total, e altura comercial das árvores e a massa específica básica, e foi feita uma análise quantitativa dos defeitos. Os resultados mostraram que ocorreram diferenças entre as espécies para massa específica, sendo que E. dunnii apresentaram os maiores valores dessa variável. Ao analisar os clones verificou-se diferenças estatísticas entre os materiais estudados para E. saligna e E. grandis. Os resultados de rendimento em madeira serrada apontaram diferenças entre as espécies, entre os diâmetros e entre os clones estudados. A espécie com maior rendimento foi E. saligna, sendo que as toras grossas das três espécies tiveram as melhores performances, os clones 7, 8, 12, 13, 1 e 3 obtiveram os maiores valores de rendimento em madeira serrada. A análise da madeira serrada mostrou que os índices de empenamento foram diferentes entre as espécies, entre os diâmetros. O encurvamento foi maior para E. saligna e o arqueamento da madeira serrada foi maior em E. dunnii. Quando analisado os empenamentos em relação a classe diamétrica os resultados apontaram que as toras finas apresentaram os maiores valores de encurvamento e arqueamento. O resultado do índice de rachaduras não apresentou diferenças entre as espécies, no entanto ao analisar o rachamento em relação aos diâmetros notou-se diferenças. Entre os clones não se verificou a diferença entre os índices de rachadura. A análise quantitativa dos defeitos na madeira serrada revelou que 68%, 53%, 69% das tábuas de E. dunnii, E. saligna e E. grandis apresentaram simultaneamente, arqueamento, encurvamento e rachaduras. A análise da DRL indicou diferenças significativas entre as espécies sendo que E. dunnii obteve os menores valores de DRL. Para as classes diamétricas estudadas os níveis de DRL foram mais altos nas toras finas de E. grandis, toras médias de E. saligna e toras grossas de E. dunnii. Os clones com os maiores valores de DRL foram o 1, 5, 9, 10, 11 e 14. A análise das correlações apresentou relação significativa entre DAP, altura, altura comercial, rendimento em madeira serrada, perdas no rendimento causadas pelo destopo das rachaduras, índices de encurvamento e arqueamento. As conclusões apontaram que o aumento nas dimensões das árvores estudadas melhorou o rendimento em madeira serrada, e aumentou a qualidade das tábuas Palavras chave: Madeira serrada, Eucalyptus, ContribuiçãoAbstract: The objective of this research was to increase the knowledge of the unfolding of three species of Eucalyptus, E. dunnii, E. saligna and E. grandis. To achieve this goal was analyzed the influence of the diameter and of the clone on the basic density, the quality of material sawed, saw wood yield and residual longitudinal strain, (DRL). Linear correlations were also built on the features. For this, the experimental design was a factorial double associating species and diameter, and species and clone, 75 logs were collected from three species of eucalyptus, divided into 25 logs for each species, diameter classes 3 and 15 clones. Were measured the yield of lumber, the variability of sawn pieces, indexes bending, bowing, and cracking, the DRL, the diameter at breast height (DBH), total height, and height of the trees and the basic density, and was made a quantitative analysis of defects. The results showed that there were differences between the species to density, and E. dunnii showed higher values of this variable. By analyzing the clones was found statistical differences between the studied materials for E. saligna and E. grandis. The results of sawn wood yield showed differences between species, and between the diameters between clones. The species with the highest yield was E. saligna, and the thick logs of the three species had the best performances, clones 7, 8, 12, 13, 1 and 3 had the highest yield values for lumber. The analysis showed that lumber warping indices were different between species, between the diameters. The bending was higher for E. saligna and warping of lumber was higher in E. dunnii. When analyzed in relation to the warping diameter class the results indicated that the thin logs showed higher bending and arching. The result of the splitting index did not differ between species, however to analyze cracking in relation to the diameters was noted differences. Among the clones there was no difference between the rates of crack. The quantitative analysis of defects in the lumber revealed that 68%, 53%, 69% of the tablets of E. dunnii, E. saligna and E. grandis showed simultaneously arching, bending and cracking. The DRL analysis indicated significant differences among the species with which E. dunnii obtained the lowest values of DRL. To diametric classes studied levels were higher in DRL logs fine E. grandis, medium timber E. saligna and thick logs E. dunnii. Clones with the highest values of the DRL were 1, 5, 9, 10, 11 and 14. The correlation analysis showed a significant relationship between DBH, height, height commercial saw wood yield, yield reductions caused by cracks, bending and arching ratios. The findings showed that the increase in the dimensions of the studied trees improved the yield of lumber, and increased the quality of the boards. Key words: Saw wood, Eucalyptus, Contributio

Awareness and Attitudes towards Advance Care Directives (ACDs): An Online Survey of Portuguese Adults

Evidence shows that facilitated advance decisions can increase the number of meaningful and valid Advance Care Directives (ACDs) and improve the quality of care when EndOf-Life (EOL) is near. Little is known about the awareness and attitudes of Portuguese adults towards ACDs. The present study aims to assess the knowledge, attitudes, and preferences of a sample of Portuguese adults regarding EOL care decisions and ACDs. (2) Methods: A total of 1024 adults were assessed with an online cross-sectional survey collecting information on sociodemographic factors, knowledge, attitudes and preferences regarding advance decisions and EOL care. (3) Results: Participants had a mean age of 40.28 ± 11.41 years. Most were female and had a professional background related to healthcare. While 76.37% of participants had heard of ACDs, only a small percentage (2.34%) had actually ever made an ACD. Knowledge levels were weakly correlated with attitudes regarding ACDs (r = −0.344; p < 0.01). (4) Conclusions: Participants lacked a comprehensive understanding about ACDs, but revealed positive attitudes towards their use and usefulness. Further research can inform efforts to improve ACD engagement in this population. The discussion about ACDs should be part of health promotion education with a focus on planning for a comfortable and peaceful deathinfo:eu-repo/semantics/publishedVersio

Biodentine for Furcation Perforation Repair: An Animal Study with Histological, Radiographic and Micro-Computed Tomographic Assessment

Introduction: Biodentine has been scarcely studied as a furcation perforation (FP) repair material, mostly by in vitro methodologies. This animal study aimed to compare the histological responses, radiographic, and micro-computed tomographic (micro-CT) outcomes after FP repair with Biodentine or ProRoot MTA (MTA) in dogs’ teeth. Methods and Materials: Fifty teeth from five dogs were divided into 4 groups: MTA (n=20, FP repaired with ProRoot MTA), BDT (n=20, FP repaired with Biodentine), PC (n=5, positive control, FP without repair) and NC (n=5, negative control, without perforation). The animals were euthanized after 4 months. Histological assessment included inflammatory cell infiltration, hard tissue resorption, hard tissue repair, and cement repair in the furcation area. Immediate postoperative and 4months follow-up radiographs were compared for radiolucency in the furcation region. The volume of extruded material was quantified using micro-CT images. Results: The tested materials showed equivalent radiographic response, together with similar hard tissue resorption and repair but, BDT group showed significantly less inflammation, lower volume of extruded material and higher cement repair than MTA group. Conclusion: The outcomes of this study, taken together with other favorable results in literature, are highly suggestive that Biodentine is a promising biomaterial to be used for FP repair.Keywords: Biodentine; Biomaterial; Endodontics; Furcation Perforation; Imaging; Micro-Computed Tomograph