Harvesting undelimbed Scots pine (Pinus sylvestris L.) from first thinnings for integrated production of kraft pulp and energy

The present study evaluates the feasibility of undelimbed Scots pine (Pinus sylvestris L.) for integrated production of pulp and energy in a kraft pulp mill from the technical, economic and environmental points of view, focusing on the potential of bundle harvesting. The feasibility of tree sections for pulp production was tested by conducting an industrial wood-handling experiment, laboratory cooking and bleaching trials, using conventional small-diameter Scots pine pulpwood as a reference. These trials showed that undelimbed Scots pine sections can be processed in favourable conditions as a blend with conventional small-diameter pulpwood without reducing the pulp quality. However, fibre losses at various phases of the process may increase when using undelimbed material. In the economic evaluation, both pulp production and wood procurement costs were considered, using the relative wood paying capability of a kraft pulp mill as a determinant. The calculations were made for three Scots pine first-thinning stands with the breast-height diameter of the removal (6 12 cm) as the main distinctive factor. The supply chains included in the comparison were based on cut-to-length harvesting, whole-tree harvesting and bundle harvesting (whole-tree bundling). With the current ratio of pulp and energy prices, the wood paying capability declines with an increase in the proportion of the energy fraction of the raw material. The supply system based on the cut-to-length method was the most efficient option, resulting in the highest residual value at stump in most cases. A decline in the pulp price and an increase in the energy price improved the competitiveness of the whole-tree systems. With short truck transportation distances and low pulp prices, however, the harvesting of loose whole trees can result in higher residual value at stump in small-diameter stands. While savings in transportation costs did not compensate for the high cutting and compaction costs by the second prototype of the bundle harvester, an increase in transportation distances improved its competitiveness. Since harvesting undelimbed assortments increases nutrient export from the site, which can affect soil productivity, the whole-tree alternatives included in the present study cannot be recommended on infertile peatlands and mineral soils. The harvesting of loose whole trees or bundled whole trees implies a reduction in protective logging residues and an increase in site traffic or payloads. These factors increase the risk of soil damage, especially on peat soils with poor bearing capacity. Within the wood procurement parameters which were examined, the CO2 emissions of the supply systems varied from 13 27 kg m3. Compaction of whole trees into bundles reduced emissions from transportation by 30 39%, but these reductions were insufficient to compensate for the increased emissions from cutting and compaction.

Vehicle Routing Problem with Load Compatibility Constraints

The major contribution of this paper is to introduce load compatibility constraints in the mathematical model for the capacitated vehicle routing problem with pickup and deliveries. The employee transportation problem in the Indian call centers and transportation of hazardous materials provided the motivation for this variation. In this paper we develop a integer programming model for the vehicle routing problem with load compatibility constraints. Specifically two types of load compatability constraints are introduced, namely mutual exclusion and conditional exclusion. The model is demonstrated with an application from the employee transportation problem in the Indian call centers.

Sliding wear of Al2O3-SiC-(Al,Si) composites against a steel counterface

The sliding-wear behavior of Al2O3-SiC-Al composites prepared by melt oxidation against a steel counterface has been recorded in a pin-on-disk machine. At high speeds and pressures (10 m/s, 20 MPa), friction and wear appear to be principally controlled by the in-situ formation of an interfacial film that consists of a layer of Fe3O4. The formation of this him is examined as a function of sliding speed, lubrication, and composite microstructure. A model is proposed in which high surface temperatures cause the preferential extrusion of aluminum from the composite onto the pin/disk interface. This promotes the adhesive pickup of iron and its oxidation to form a stable tribologically beneficial layer of Fe3O4.

An efficient web cache replacement policy

Several replacement policies for web caches have been proposed and studied extensively in the literature. Different replacement policies perform better in terms of (i) the number of objects found in the cache (cache hit), (ii) the network traffic avoided by fetching the referenced object from the cache, or (iii) the savings in response time. In this paper, we propose a simple and efficient replacement policy (hereafter known as SE) which improves all three performance measures. Trace-driven simulations were done to evaluate the performance of SE. We compare SE with two widely used and efficient replacement policies, namely Least Recently Used (LRU) and Least Unified Value (LUV) algorithms. Our results show that SE performs at least as well as, if not better than, both these replacement policies. Unlike various other replacement policies proposed in literature, our SE policy does not require parameter tuning or a-priori trace analysis and has an efficient and simple implementation that can be incorporated in any existing proxy server or web server with ease.

Measurement of Electron Spin Lifetime and Optical Orientation Efficiency in Germanium Using Electrical Detection of Radio Frequency Modulated Spin Polarization

We propose and demonstrate a technique for electrical detection of polarized spins in semiconductors in zero applied magnetic fields. Spin polarization is generated by optical injection using circularly polarized light which is modulated rapidly using an electro-optic cell. The modulated spin polarization generates a weak time-varying magnetic field which is detected by a sensitive radio-frequency coil. Using a calibrated pickup coil and amplification electronics, clear signals were obtained for bulk GaAs and Ge samples from which an optical spin orientation efficiency of 4.8% could be determined for Ge at 1342 nm excitation wavelength. In the presence of a small external magnetic field, the signal decayed according to the Hanle effect, from which a spin lifetime of 4.6 +/- 1.0 ns for electrons in bulk Ge at 127 K was extracted.

High sensitivity detection of radio-frequency modulated magnetic moment in semiconductors

An experimental setup has been realized to measure weak magnetic moments which can be modulated at radio frequencies (similar to 1-5 MHz). Using an optimized radio-frequency (RF) pickup coil and lock-in amplifier, an experimental sensitivity of 10(-15) Am(2) corresponding to 10(-18) emu has been demonstrated with a 1 s time constant. The detection limit at room temperature is 9.3 x 10(-16) Am(2)/root Hz limited by Johnson noise of the coil. The setup has been used to directly measure the magnetic moment due to a small number (similar to 7 x 10(8)) of spin polarized electrons generated by polarization modulated optical radiation in GaAs and Ge. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3654229]

New static 3-step distance relay

A new static 3-step distance relay based on the principle of multi-input phase comparison is described in the paper. Design principles and typical discriminating and logic circuits are described for the new relaying system. The relaying system uses semiconductor circuits throughout and features high speed and good performance. The comparator model, which effects multi-input phase comparison, has been devised to provide reliable pickup for closein faults, and to achieve an improved polar characteristic in the complex- impedance plane, which fits around only the fault area of a transmission line. Operating time of the relay is less than 1 cycle for unbalanced faults, and less than a halfcycle for 3-phase faults. Protective circuits have also been added to detect power swing and to block tripping for a predetermined number of power-swing cycles. The operating characteristics of the relay, as expressed by accuracy/range charts, are presented.

Three-system and single-system static distance relays

Static distance relays employing semiconductor devices as their active elements offer many advantages over the conventional electromagnetic and rectifier relays. The paper describes single-system and three-system static distance relays, which depend for their operation on the instantaneous-comparison or `block-spike¿ scheme. Design principles and typical discriminating and logic circuits are described for the new relaying equipment. The relaying circuitry has been devised for obtaining uniform performance on all kinds of faults, by the use of two phase detectors¿one for multiphase faults and one for earth faults. The phase detector for multiphase faults provides an improved polar characteristic in the complex-impedance plane, which fits only around the fault area of a transmission line. The other features of the relay are: reliable pickup for close-in faults, least susceptibility to maloperation under power-swing conditions, and reduction in cost and panel space required. The operating characteristics of the relays, as expressed by accuracy/range charts, are also presented.

O Congresso Nacional e a política externa brasileira : posicionamento dos senadores frente às negociações para a formação da ALCA (1994-2005)

Analisa o posicionamento dos integrantes do Congresso Nacional frente às negociações para a formação da Área de Livre Comércio das Américas (ALCA), a concentrar sua atenção sobre o Senado Federal, com eventuais incursões pela Câmara dos Deputados. O período por nós delimitado compreende, respectivamente, o lançamento da proposta pela integração continental, ocorrida na I Cúpula das Américas, nos EUA, em 1994, até o ano de 2005, em que se evidenciou a paralisação do processo negociador. Dois fatores estimularam-nos a realizar esta tarefa. Primeiro, colocar à prova a tese, disseminada pelo senso comum, de que o Parlamento não demonstra interesse por questões ou assuntos internacionais. Segundo, fornecer uma contribuição à escassa bibliografia disponível a respeito da relação entre os congressistas e a produção da política externa brasileira de integração regional, em particular. Apesar de não ignorarmos o papel predominante do Poder Executivo na formulação e condução da política externa nacional, e nem a comprovada carência de mecanismos participativos e decisórios formais à disposição do Parlamento para atuar nas diferentes facetas deste plano, procuramos aferir em que medida a atividade parlamentar se restringe ou não, na prática, ao seu exercício constitucional de aprovar ou rejeitar matérias sobre política exterior, conforme nos aponta o senso comum. O caráter polêmico das negociações e dos debates ocorridos no Brasil a respeito da conformação da ALCA, ao longo de mais de uma década, levou-nos a questionar qual teria sido o posicionamento dos congressistas com relação ao assunto, ou seja, se teriam manifestado interesse em se envolver mais intensamente com a questão, ou se reservado a debatê-la somente na ocasião em que fosse submetida, na forma de um acordo, à sua apreciação. A elaboração do presente trabalho orientou-se pela pretensão em alcançar respostas para duas perguntas formuladas por nós: a ausência de mecanismos formais de participação parlamentar nas negociações sobre a ALCA teria refletido um suposto desinteresse dos senadores pela questão? Em que medida esta referida ausência não teria impelido o Parlamento a buscar influenciar o processo por outros meios, ou até mesmo fomentado demandas pela ampliação de seu papel constitucional no tratamento de questões externas? Para tentar responder a tais perguntas, servimo-nos especialmente dos apanhamentos taquigráficos dos pronunciamentos realizados pelos senadores; de proposições elaboradas pelos congressistas e de atas e notas tquigráficas de audiências públicas promovidas por Comissões do Congresso Nacional.

Untersuchungen zur Qualität von Doraden auf dem deutschen Markt

Mediterranean fish species and fish species from other southern countries are retailed increasingly on the German market. The fish is stored in ice eviscerated or as whole fish and imported by truck or by airplane. In the present investigation, the freshness, the sensory quality and the microbiological status was determined of gilthead sea breams (Sparus aurata) from farms in Italy and France and from sea breams (Sparus ehrenbergi) of wild captures from Senegal. It is shown, that farmed gilthead sea breams were of high sensory quality and in good microbiological conditions.

Detection of specific bacteria in water: implications of survival strategy

It is widely recognised that conventional culture techniques may underestimate true viable bacterial numbers by several orders of magnitude. The basis of this discrepancy is that a culture in or on media of high nutrient concentration is highly selective (either through ”nutrient shock” or failure to provide vital co-factors) and decreases apparent diversity; thus it is unrepresentative of the natural community. In addition, the non-culturable but viable state (NCBV) is a strategy adopted by some bacteria as a response to environmental stress. The basis for the non-culturable state is that cells placed in conditions present in the environment cannot be recultured but can be shown to maintain their viability. Consequently, these cells would not be detected by standard water quality techniques that are based on culture. In the case of pathogens, it may explain outbreaks of disease in populations that have not come into contact with the pathogen. However, the NCBV state is difficult to attribute, due to the failure to distinguish between NCBV and non-viable cells. This article will describe experiences with the fish pathogen Aeromonas salmonicida subsp. salmonicida and the application of molecular techniques for its detection and physiological analysis.

High focal depth with a pure-phase apodizer

High-density optical data storage requires high-numerical-aperture (NA) lenses and short wavelengths, But, with increasing NA and decreasing wavelength, the depth of focus (DOF) decreases rapidly. We propose to use pure-phase superresolution apodizers to optimize the axial intensity distribution and extend the DOF of an optical pickup. With this kind of apodizer, the expected DOF can be 2-4.88 times greater than that of the original system, and the spot size will be smaller than that of the original system. (C) 2001 Optical Society of America.

Low-Power Super-resolution Readout with Antimony Bismuth Alloy Film as Mask layer

Sb-Bi alloy films are proposed as a new kind of super-resolution mask layer with low readout threshold power. Using the Sb-Bi alloy film as a mask layer and SiN as a protective layer in a read-only memory disc, the super-resolution pits with diameters of 380 nm are read out by a dynamic setup, the laser wavelength is 780 nm and the numerical aperture of pickup lens is 0.45. The effects of the Sb-Bi thin film thickness, laser readout power and disc rotating velocity on the readout signal are investigated. The results show that the threshold laser power of super-resolution readout of the Sb-Bi mask layer is about 0.5 mW, and the corresponding carrier-to-noise ratio is about 20 dB at the film thickness of 50 nm. The super-resolution mechanism of the Sb-Bi alloy mask layer is discussed based on its temperature dependence of reflection.

Metodologia de projeto de turbinas eólicas de pequeno porte.

O potencial eólico do Brasil, de vento firme e com viabilidade econômica de aproveitamento, é de 143 GW. Isso equivale ao dobro de toda a capacidade da geração já instalada no país. No Brasil, a energia eólica tem uma sazonalidade complementar à energia hidrelétrica, porque os períodos de melhor condição de vento coincidem com os de menor capacidade dos reservatórios. O projeto desenvolvido neste trabalho nasceu de uma chamada pública do FINEP, e sob os auspícios do recém criado CEPER. Ao projeto foi incorporado um caráter investigativo, de contribuição científica original, resultando em um produto de tecnologia inovadora para aerogeradores de baixa potência. Dentre os objetivos do projeto, destacamos a avaliação experimental de turbinas eólicas de 5000 W de potência. Mais especificamente, dentro do objetivo geral deste projeto estão incluídas análise estrutural, análise aerodinâmica e análise de viabilidade de novos materiais a serem empregados. Para cada uma das diferentes áreas de conhecimento que compõem o projeto, será adotada a metodologia mais adequada. Para a Análise aerodinâmica foi realizada uma simulação numérica preliminar seguida de ensaios experimentais em túnel de vento. A descrição dos procedimentos adotados é apresentada no Capítulo 3. O Capítulo 4 é dedicado aos testes elétricos. Nesta etapa, foi desenvolvido um banco de testes para obtenção das características específicas das máquinas-base, como curvas de potência, rendimento elétrico, análise e perdas mecânicas e elétricas, e aquecimento. Este capítulo termina com a análise crítica dos valores obtidos. Foram realizados testes de campo de todo o conjunto montado. Atualmente, o aerogerador de 5kW encontra-se em operação, instrumentado e equipado com sistema de aquisição de dados para consolidação dos testes de confiabilidade. Os testes de campo estão ocorrendo na cidade de Campos, RJ, e abrangeram as seguintes dimensões de análise; testes de eficiência para determinação da curva de potência, níveis de ruído e atuação de dispositivos de segurança. Os resultados esperados pelo projeto foram atingidos, consolidando o projeto de um aerogerador de 5000W.

Quantificação de metais e arsênio em aerossóis grossos, finos, ultrafinos e nanoparticulados por ICP-OES em ar ambiente e emissões veiculares de motores operando com diesel/biodiesel

Na frota automotiva nacional, veículos movidos a diesel e biodiesel são utilizados em larga e pequena escala, respectivamente, fazendo com que haja uma preocupação com os gases da exaustão provenientes destes motores. Ao ser fabricado, o veículo passa por testes rigorosos das emissões gasosas, segundo as regras do PROCONVE. Porém, estes testes regulam apenas as substâncias químicas contidas na legislação vigente, cujos riscos à saúde humana e ao meio ambiente são conhecidos. Portanto, conhecer o maior número de componentes ainda não contemplados pela legislação, em especial metais no material particulado, é de suma importância para subsidiar futuras alterações e inclusões na lista de componentes regulados. De acordo com o tamanho das partículas do material particulado, podendo chegar a escalas nanométricas, a inalação deste material pode causar lesões graves no organismo, pois têm a capacidade de atingir órgãos internos. O estudo é baseado na amostragem do material particulado proveniente dos gases de motores alimentados com diesel e/ou biodiesel em diferentes proporções de combustível e ar ambiente com impactador em cascata; determinando metais e arsênio na atmosfera de diferentes localidades do estado do Rio de Janeiro e no material particulado dos gases de escape de motores de ônibus/caminhão (EURO III), por intermédio de abertura ácida do material coletado e da técnica analítica ICP-OES. Os resultados obtidos para motor EURO III variaram de 100 a 10000 ng m-3, com a redução de emissão conforme adição de biodiesel no diesel sendo comprovada. Porém, em todas as proporções de combustíveis empregadas, houve grande incidência de emissão de partículas em escala manométrica, sendo esse comportamento também observado nas amostragens em ar ambiente. Neste caso, teores de 1,0 a 45,0 ng m-3 evidenciaram Caxias e Madureira como locais mais poluídos dos amostrados. Ni é o metal que possui situação mais alarmante, pois em todos os tamanhos de partícula e locais amostrados, os teores deste elemento foram superiores ao permitido pela legislação internacional. A análise estatística multivariada propôs que os combustíveis B10 e B15 são quimicamente semelhantes, enquanto B5 e B20 sofrem fortes alterações no decorrer de sua combustão e a correlação de Pearson mostrou em ar ambiente, que locais com níveis próximos de poluição apresentaram similaridade nos resultados, a qualidade do ar de Madureira é afetado predominantemente pela construção civil e tráfego, a presença da Baía de Guanabara ao redor da Cidade Universitária influencia nas emissões, a refinaria em Caxias é responsável por emissões importantes de metais e no Parque Nacional de Itatiaia , ao contrário de que se supunha, não está totalmente livre de poluição