88 research outputs found
Baculum morphology predicts reproductive success of male house mice under sexual selection
No full textStockley P, Ramm SA, Sherborne AL, Thom MDF, Paterson S, Hurst JL. Baculum morphology predicts reproductive success of male house mice under sexual selection. BMC Biology. 2013;11(1): 66
Effects of density profile of MDF on stiffness and strength of nailed joints
No full textNail-head pull-through, lateral nail resistance, and single shear nailed joint tests were conducted on medium density fiberboard (MDF) with different density profiles, and the relations between the results of these tests and the density profiles of MDF were investigated. The maximum load of nail-head pull-through and the maximum load of nailed joints were little affected by the density profile. However, the ultimate strength of lateral nail resistance, the stiffness, and the yield strength of nailed joints were affected by the density profile of MDF and showed high values when the surface layer of the MDF had high density. It is known that bending performance is also influenced by density profile. Therefore, the stiffness and the yield strength of nailed joints were compared with the bending performance of MDF. The stiffness of nailed joints was positively correlated with the modulus of elasticity (MOE); in the case of CN65 nails, the initial stiffness of joints changed little in response to changes in MOE. The yield strength of nailed joints had a high positive correlation with the modulus of rupture (MOR). The stiffness and the yield strength of nailed joints showed linear relationships with MOE and MOR, respectively
Preparation of board-like moldings from composites of isolated lignins and waste paper II : effect of inorganic salt addition on board performance and evaluation of practical use of MDF
No full textBoard-shaped composites with medium density (MDF) were prepared from isolated lignins and waste newspaper, in addition to preparation of the composites with high density (HB). The board properties of both composites concerning bending strength and water resistance were improved by the addition of hardwood acetic acid lignin (HAL). The internal bond strength and water resistance of MDF, in particular the degree of thickness swelling (TS), were also improved by prolonged molding time. Adding inorganic salts contributed to the improvement of TS. The effect depended on the charge of the cation. Considering practical utilization of lignin-based MDF as a structural material, its performance was evaluated by combination of the single-shear test of nailed joints and the modulus of rigidity. As a result, this MDF had sufficient strength to be utilized as an internal shear wall material. Therefore, lignin can be considered as an alternative to conventional adhesives for the production of boards such as HB and MDF
Implementação da ferramenta DMAIC numa linha de produção de MDF
No full textMestrado em Engenharia e Gestão IndustrialO presente projeto complementa um período de estágio de 9 meses na Sonae Indústria – P.C.D.M., SA, na área da melhoria contínua, no departamento de Qualidade.
Com este trabalho pretende-se demonstrar uma possível abordagem da metodologia DMAIC na eliminação de um defeito específico da produção de ‘placas de MDF’ (Medium Density Fibreboard) – Bordos Partidos. Através dos dados recolhidos foi possível encontrar alguns dos locais críticos onde este defeito ocorreu, bem como as suas respetivas causas. Permitiu, também, sugerir algumas ideias de melhoria, que se forem implementadas será possível uma redução do material enviado para um 2º momento de inspeção visual (2ª Escolha), devido à ocorrência de Bordos Partidos.
O autor propõe, por isso, a implementação da metodologia DMAIC na redução, e consequente eliminação das causas responsáveis pelo envio de material para 2ª Escolha, quer na Sonae Indústria – P.C.D.M., SA, em Mangualde (Viseu), como nas restantes unidades fabris da sub-holding Sonae Indústria, produtoras de MDF.This project complements a 9-month internship at Sonae Indústria – P.C.D.M., SA, in the field of continuous improvement at the quality department. This work pretends to demonstrate a possible approach of DMAIC methodology in the elimination of a specific defect – Damaged Edges, during the production of 'MDF boards' (Medium Density Fibreboard). Using the data collected it was possible to find some of the critical locations where the defect has occurred, as well as their respective causes. It was also possible to suggest some ideas for improvement, which if implemented will enable the reduction of the material sent to a 2nd moment of visual inspection (2nd Choice), due to the occurrence of Damaged Edges. Therefore, the author proposes the implementation of the DMAIC methodology in the reduction, and elimination of the causes responsible for sending material to the 2nd Choice at Sonae Indústria – P.C.D.M., SA, in Mangualde (Viseu), as in other plants of the sub-holding Sonae Indústria, producers of MDF
Spatially clustered resources increase male aggregation and mating duration in Drosophila melanogaster
No full textIn environments where females mate multiply, males should adjust their behaviour and physiology in response to the perceived level of sperm competition to maximize their fitness. Evidence of such plasticity has been found in several laboratory and field studies, but little is known about the cues stimulating these responses in natural populations. One way in which males appear to assess sperm competition risk is through encounter rates with conspecific males. Such encounter rates may be driven by the spatial distribution of resources required by males (i.e. food patches or potential mates), which in turn affects local density. However, explicit links between resource distribution, male encounter rates and shifts in behaviour related to sperm competition have not been demonstrated. We found that when group size of Drosophila melanogaster males was held constant, a small decrease in the distance between patches of food resources had striking effects on male behaviour. Compared to those from dispersed resources, males on clustered resources had a significantly reduced intermale distance (and hence encounter rate) and subsequently a longer noncompetitive copulation duration, previously shown to be a reliable indicator of male perception of sperm competition risk. The aggregation of resources, operating via increased encounter rate, can stimulate shifts in behaviour affecting male sperm competition performance. Given that the spatial distribution of resources is typically variable in natural populations (and often unpredictable), selection is likely to favour the evolution of plasticity in sexual behaviour where resource aggregation increases the probability of sperm competition
Straw Wastes from an Environmental Disaster to ECO-Board towards a Sustainable Urban Environment
No full textAbstractThe purpose of this paper is to develop an economical, sustainable, and environmentally friendly straw Medium Density Fiber board (MDF) process, capable of full-scale manufacturing and to produce ECO-MDF boards of requested quality. The investigated straw was based on rice. In the environmental perspective the agricultural straw-waste is a suitable source for producing MDF to avoid open field burning and to capture carbon dioxide (CO2). Additionally, the straw ECO-MDF panels can be used in the architecture and urban design as a material in furniture or hardscape manufacture
A Surface EMG System: Local Muscle Fatigue Detection
No full textIn the last 4 decades, surface electromyography (sEMG) signal processing has been applied to detect local muscle fatigue, this non-invasive approach is suitable for detecting EMG signals generated by athletes in motion. Also, EMG could directly reveal the muscle’s performance like endurance and recruitment of motor units, which is hard to be obtained by other methods. With the sEMG system, we can research whether EMG signals can be used to measure muscle fatigue and how this relates to injury risk. This thesis aims to build a sensor node for sEMG to detect local muscle fatigue. An sEMG system is built for this purpose, and a physiological experiment is designed to collect sEMG signals from human muscle (Vastus Medialis) using the sEMG system. Both isometric and isotonic exercises are studied. The data analyzing method is calculating mean power spectrum frequency (MNF), median power spectrum frequency (MDF), and muscle fiber propagation velocity (MFPV) of the collected sEMG signals, because local muscle fatigue is related to MNF/MDF decrease and MFPV decrease. 5 groups of isometric exercise, wall-sit and 2 groups of isotonic exercise, cycling, are recorded. All the athletes are healthy males, around 25. The data analyzing result shows that MNF/MDF decrease is related to muscle fatigue, and MFPV changes similarly with MNF/MDF
Population fragmentation drives up genetic diversity in signals of individual identity
No full textMany species advertise their unique identity to conspecifics using dedicated individuality signals: one familiar example is human faces. But how unique in the global population do these signals need to be? While human faces are highly variable, each person interacts with many fewer individuals than are found in the total population. This raises the question of how evolutionary mechanisms drive up population-wide diversity when selection occurs at such a local level. We use an individual-based model in which individuals broadcast their identity and quality in separate, genetically-coded signals. Mimicking, for example, scent marking mammal species, females in the model assess males using the quality signal, then attempt to relocate the highest quality male using his identity signal. We ask how population fragmentation affects genetic diversity in the individual identity-signalling region under sexual selection, predicting one of two opposing outcomes: 1) divided populations evolve fewer signal variants globally, since repetition of signals is not costly when individuals interact only with local conspecifics, or 2) stochasticity in mutation and selection cause divergence among subpopulations, increasing the global number of signal variants. We show that local selection drives up global genetic diversity substantially in fragmented populations, even with extremely low rates of dispersal. Because new signal variants arise by mutation and then sweep through their subpopulation, a fragmented population has more global signal variation. This result furthers our understanding of how high levels of diversity in individuality signals are maintained
The Case of Re-plex: Wastewater to Building material: Life Cycle Assessment on the use of Re-plex as interior finishing material
No full textWith the increasing focus from policymakers to a circular economy, assessing the environmental impacts of circular products is becoming more important. In this thesis a Life Cycle Assessment of the new circular composite Re-plex is performed. The Re-plex can be used as building material. Re-plex is produced from Kaumera Nereda® Gum recovered from Nereda® wastewater sludge, and Recell® cellulose recovered from wastewater. Re-plex is still in the developmental phase, this LCA is performed to aid engineers to reduce the environmental impacts of the Re-plex composite. A comparative LCA is performed in which the current Re-plex production is compared to Fire-retardant Medium Density Fibreboard (FR-MDF) with the ILCD impact assessment family. The functional unit is 1 year of 1m2 use of interior finishing material.The Re-plex has a better characterisation result in the impact category; Human Health (HH), respiratory effects, inorganics. The FR-MDF has better characterisation results in the impact categories; Climate change; Ecosystem Quality (EQ), acidification; EQ, freshwater ecotoxicity; EQ, freshwater eutrophication; EQ ionizing radiation; EQ, marine eutrophication; EQ, marine eutrophication; Human Health (HH), carcinogenic effects; HH, ionizing radiation; HH, non-carcinogenic effects; HH, ozone layer depletion; HH, photochemical ozone creation; Resources (RS), land use; and RS, mineral, fossils and renewables. Scenarios are developed to improve the environmental performance of the Re-plex production. Increasing the amount of cellulose in Re-plex does not seem to improve the environmental performance. Three scenarios do improve the environmental performance; Replacing citric acid by succinic acid; improving the energy efficiency; and drying the Kaumera Gum before transport. These three improvements are combined in the new Re-plex scenario. The improved scenario has better characterisation results than FR-MDF in the ten impact categories; Climate change; EQ, acidification; EQ, freshwater ecotoxicity; EQ, freshwater eutrophication; EQ, marine eutrophication; EQ, marine eutrophication; HH, carcinogenic effects; HH, non-carcinogenic effects; HH, photochemical ozone creation; and HH, respiratory effects, inorganics. FR-MDF scores better in the five impact categories; EQ ionizing radiation; HH, ionizing radiation; HH, ozone layer depletion; RS, land use; and RS, mineral, fossils and renewables. Engineers working on Re-plex are advised to change the use of citric acid to a better environmentally performing material. The environmental benefit of changing this material will add more value to a Re-plex product than the lower price when using citric acid. Further, the focus should be on improving the energy efficiency of Re-plex production and realising a lifetime of Re-plex of 32 years, similar to MDF. If these improvements can be realised, Re-plex has a better environmental performance than FR-MDF.Industrial Ecolog
Implantação de um estudo prospectivo : pesquisa-ação no segmento de painéis tipo MDF, no setor madeireiro no estado do Paraná
No full textOrientador : Dr. Prof. Marcelo Gechele CletoDissertação (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia de Produção. Defesa: Curitiba, 16/12/2014Inclui referênciasÁrea de concentração: Tecnologia e inovaçãoResumo: No atual cenário, de progresso e expansão da indústria brasileira, a rotina das organizações sofre com as rápidas mudanças dos avanços tecnológicos, que contribuem para o aumento da competição. Desta forma, se faz necessário que as empresas preparem-se de maneira ordenada para enfrentar os novos desafios. A prospecção tecnológica é uma atividade capaz de orientar e conduzir o planejamento das atividades industriais a longo prazo, pois visa entender as potencialidades, evolução, características e efeitos das mudanças tecnológicas. Neste contexto, elaborar projetos prospectivos é uma forma de contribuir para que a atividade do estudo de futuros se faça presente no meio industrial. Sendo assim, o objetivo deste trabalho foi implantar um estudo prospectivo, utilizando o método Cenários e as técnicas SWOT, Delphi, Árvore Morfológica e TGN dentro do segmento de painéis em MDF no estado do Paraná, de forma que cenários prospectivos sejam estabelecidos no horizonte 2014-2019. A pesquisa é aplicada, possuindo uma abordagem qualitativa, e se caracterizando como descritiva e exploratória em relação ao objeto de estudo. O instrumento proposto para o trabalho foi à pesquisa-ação, de forma que a coordenadora da pesquisa foi à própria autora do trabalho. Esta pesquisa foi conduzida por um grupo com seis especialistas nas áreas acadêmicas e industriais, do segmento de painéis em MDF. A pesquisa contou com a participação da Universidade Federal do Paraná e da Associação Paranaense de Empresas de Base Florestal. Com base na implantação das técnicas e do método Cenários, o grupo de especialistas e a pesquisadora avaliaram as ferramentas como sendo consistentes e confiáveis para serem executadas dentro de estudos prospectivos. Elas permitiram a elaboração de três cenários prospectivos a partir do conhecimento e experiência do grupo de pesquisa. E ainda, a partir deste estudo foi possível estabelecer um método preliminar que poderá servir como instrumento para conduzir novos estudos prospectivos.
Palavras Chaves: Prospecção Tecnológica, Técnicas Prospectivas, Cenários Prospectivos, Métodos Prospectivos.Abstract: In the current scenario, progress and expansion of the Brazilian industry, the routine of organizations suffers from the rapid change of technological advances, which have contributed to increased competition. Thus, it is necessary for companies to get ready in an orderly manner to meet the new challenges. Technology forecasting is an activity able to guide and lead the planning of long-term industrial activities; it aims to understand the potential, evolution, characteristics and effects of technological change. In this context, develop prospective projects is a way to contribute to the future study of the activity being present in the industrial environment. Thus, the objective of this work deploy a prospective study using the scenarios method and SWOT techniques, Delphi, Morphological and TGN tree inside the panel segment in MDF in Paraná so that prospective scenarios are set on the horizon 2014-2019. The research is applied, having a qualitative approach, and is characterized as descriptive and exploratory in relation to the object of study. The proposed instrument for the job was action research, so that the research coordinator was the very author of the work. This research was conducted by a group of six experts in academic and industrial areas, the panel segment in MDF. The research included the participation of the Federal University of Paraná and the Paraná Association of Forest-Based Enterprises. Based on the deployment of techniques and scenarios method, the group of experts and the researcher assess the tools to be consistent and reliable to run in prospective studies. They allowed three scenarios were developed from the knowledge and experience of the research group. And yet, from this study it was possible to establish a primary method that can serve as a tool for conducting further prospective studies.
Keywords: Technological Forecasting, Forward Techniques, Prospective Scenarios, Prospective Method
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