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Artillery and warfare 1945-2025Bailey, J. P. A. January 2009 (has links)
For millennia battles were essentially affairs of linear encounter. From the 10th Century to the 20th Century, artillery generally fired directly in the two dimensional plane,limiting potential effects. The development of indirect fire changed this , two-dimensional model. Warfare became not so much a matter of linear encounter as one of engagement as cross and throughout an area; and artillery dominated land operations in both the First and Second World Wars as a result. Firepower was subsequently often applied in even greater weights, but its effects were frequently excessive and high-value targets proved elusive. During the Cold War in Europe,the importance of field artillery wanded relative to other arms. Artillery could only regain its utility by acquiring the highest-value targets and engaging them effectively with the appropriate degree of force in time and space true precision, as opposed to mere accuracy at a point. Improvements in target acquisition and accuracy will enable land systems once more to engage targets effectively throughout the battlespace with implications for warfare analogous to those precipitated by the introduction of indirect fire a century ago. Land operations will become increasingly three-dimensional and Joint. The effects of fire will increasingly be applied in, not merely via, the third dimensions, since targets themselves will increasingly be located, not just on the area of a battlefield, but in the volume of three-dimensional battlespace with values of indetermined by considerations of the fourth dimension, time. Fire, lethal and non-lethal, will also be targeted in other less tangible dimensions such as cyber-space and new types of 'virtual counterfire' will also emerge in the forms of legal and moral restraint. All will be viewed through the lens of perceptions. The burgeoning of firepower from all sources now becomes the spur for changes in the relationship between the land and air components, mindful of those novel factors that will increasingly inhibit the application of that firepower.
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[en] DYNAMICS OF A SLENDER ROTATING COLUMN SUBJECT TO THE STICK-SLIP ACTION IN TWO DISTINCT REGIONS / [pt] DINÂMICA DE UMA COLUNA ROTATIVA ESBELTA SUJEITA À AÇÃO DE STICK-SLIP EM DUAS REGIÕES DISTINTASADRIANO DOMENY DOS SANTOS 04 May 2016 (has links)
[pt] Este trabalho apresenta um estudo do comportamento dinâmico de
uma bancada de testes representativa do sistema real de perfuração, composta
por um motor CC acoplado a um sistema físico torcional, sujeita a
fontes de atrito que induzem um regime de stick-slip no sistema em duas
regiões distintas. O estudo incluiu a identificação de parâmetros da bancada
de testes por meio de uma série de ensaios experimentais; e a caracterização
do atrito, por meio do levantamento experimental da curva do coeficiente
de atrito, em função da velocidade angular dos rotores principais. O intuito
inicial foi a obtenção de um modelo numérico que fosse o mais simples
possível e que representasse bem a bancada de testes. Uma vez obtido o modelo
numérico, prosseguiu-se com uma série de simulações que permitissem
uma caracterização indireta do regime de atrito ao qual estivessem submetidos
os rotores principais, partindo-se apenas de medições de parâmetros no
motor. Esse estudo é de grande relevância para a compreensão qualitativa
da dinâmica do sistema real de perfuração, uma vez que ainda hoje não
há técnicas totalmente confiáveis para caracterização do comportamento da
coluna no fundo do poço a partir de dados da superfície somente. / [en] This paper presents a study of the dynamic behavior of a
representative test bench of a real rotary drilling system, comprising a DC
motor coupled to a very exible torsional system subjected to sources of
friction which can induce self-excitation into two distinct regions of the
system. The study includes the identification of parameter settings from the
test bench by means of a series of experimental tests and characterization of
friction, by obtaining the experimental curve of the friction coefficient as a
function of the angular speed of the main rotor. The initial aim was to obtain
a numerical model as simple as possible, capable of representing the test
bench. Once obtained the numerical model, a series of numerical simulations
were done, which allow an indirect characterization of the friction condition
to which main rotors were subjected, starting only with the parameters
measured at the drive. This study is of great importance for a qualitative
understanding of the dynamics of the real drilling system, since today there
is no fully reliable techniques to characterize the behavior of the column in
the deep from surface data only.
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Produtos naturais e o parasitoide Trichospilus diatraeae (Hymenoptera: Eulophidae) no controle de Diaphania hyalinata (Lepidoptera: Crambidae) / Natural products and Trichospilus diatraeae parasitoid (Hymenoptera: Eulophidae) in control Diaphania hyalinata (Lepidoptera: Crambidae)Silva, Isabel Moreira da 19 July 2012 (has links)
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Previous issue date: 2012-07-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The family Cucurbitaceae presents dicotyledonous plants with food, economic and social importance. Diaphania hyalinata (Linnaeus, 1758) (Lepidoptera: Crambidae) can reduce yield by damaging leaves and fruits of these plants. This pest is controlled primarily with chemical insecticides, but less aggressive methods are been studied. The aim was to evaluate the development of Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae), the effects of density on parasitism age of the pupae of D. hyalinata on reproduction of the parasitoid, besides evaluating the toxicity of both essential oils and the commercial product Azamax® on eggs, larvae and pupae of this pest. The experiments were developed at the Laboratory of Biological Control of Insects (LCBI) of the Institute of Biotechnology Applied to Agriculture (BIOAGRO) of the University Federal of Viçosa (UFV) in Viçosa, Minas Gerais. In the first study, reproductive aspects of T. diatraeae were evaluated. Ten 48 hours old D. hyalinata pupae were individualized and exposed to parasitism by ten females of this parasitoid during 24 hours. The parasitism and emergence of the progeny was 100% and 90% respectively. Duration of the life cycle of T. diatraeae was 19.11 ± 0.11 days with 167.78 ± 23.79 offspring per pupae and sex ratio of 0.94 ± 0.01. The second study (parasitoid density and age of pupae) had 12 replications per treatment. Pupae of D.
hyalinata were exposed to different densities of T. diatraeae (1:1, 4:1, 8:1, 12:1, 16:1, 20:1 and 24:1) females for 24 hours. Parasitoid density did not affect percentage of parasitism and emergence of T. diatraeae. Increasing density of T. diatraeae reduced progeny, sex ratio, longevity and width of head capsule of females and males of this parasitoid. The duration of the life cycle of T. diatraeae was proportional to density increased of its females. The effect of pupae age was assessed with isolating them with different ages (24, 48, 72, 96, 120 and 144h) and being exposed for 24 hours to eight parasitoids each. Age of D. hyalinata pupae did not affect percentage of emergence, parasitism, sex ratio and longevity of T. diatraeae females and males. Increasing pupae age reduced offspring, life cycle and head capsule of T. diatraeae. In the third study, each development stage of D. hyalinata received different concentrations of essential oils of cinnamon, clove, orange and the Azamax® product (0.25% to 25%) dissolved in acetone and the control with only, acetone. Paper disks containing 20 eggs were sprayed with each material on four disks per treatment each representing a replication. Squash leaves were immersed pretreatment and provided to third instar D. hyalinata caterpillars of with four replications of 10 larvae each. Moth pupae were immersed for five seconds in each treatment, with four replications of 10 pupae each. The LC50 was 1.70, 0.97, 40.08 and 1.18 μL/ml for eggs, 14.07, 48.92, 90.31 and 6.18 μL/ml for pupae and LC90 was 6.17, 2.38, 648.50 and 15.67 μL/ml for eggs and 269.06, 642.23, 1079.63 and 16.08
μL/ml for pupae, respectively, with cinnamon, clove and orange oils and Azamax®. The toxicity of cinnamon and clove oils had values for LC50 of 10.82 and 18.75 μL/ml respectively and for the LC90 of clove oil (46.21 μL/ml) and cinnamon (37.21 μL/ml) were estimated for caterpillars of D. hyalinata due to the low mortality on the other
treatments. Trichospilus diatraeae parasitized and produced offspring in pupae of D. hyalinata and have the potential to control pupae of this insect. Pupae age is not discriminate by this the parasitoid and up to eight parasitoids per pupae are favorable for its development. The commercial product Azamax® has potential to control this pest. The cinnamon oil was more toxic for larvae and pupae and clove oils more toxic to eggs of D. hyalinata. / Cucurbitaceae apresenta plantas dicotiledôneas com importância alimentícia, econômica e social. Diaphania hyalinata (Linnaeus, 1758) (Lepidoptera: Crambidae), pode causar perdas na produção por danos à folhas e frutos e se destaca entre as pragas dessa família. Seu controle é realizado principalmente com inseticidas químicos, porém métodos menos agressivos ao ambiente vem sendo estudados. O objetivo deste trabalho foi avaliar o desenvolvimento de Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae), o efeito da densidade de parasitismo e da idade da pupa na reprodução desse parasitoide no hospedeiro natural D. hyalinata, além de avaliar a toxicidade de óleos essenciais e do produto comercial Azamax® nas fases de ovo, lagarta e pupa dessa praga. Os experimentos foram realizados no Laboratório de Controle Biológico de Insetos (LCBI) do Instituto de Biotecnologia Aplicada a Agropecuária (BIOAGRO) da Universidade Federal de Viçosa (UFV) em Viçosa, Minas Gerais. No primeiro estudo, aspectos reprodutivos de T. diatraeae foram avaliados. Dez pupas de D. hyalinata com 48 horas de idade foram individualizadas e expostas ao parasitismo por dez fêmeas do parasitoide, cada uma, por 24 horas. O parasitismo e a emergência de progênie foram de 100% e 90%, respectivamente. A duração do ciclo de vida de T. diatraeae foi de 19,11 ± 0,11 dias com 167,78 ± 23,79 descendentes por pupa e razão sexual de 0,94 ± 0,01. No segundo estudo, cada tratamento (densidade de parasitoide e idade de pupa) teve 12 repetições. Pupas de D. hyalinata foram expostas a diferentes densidades de fêmeas de T. diatraeae (1:1, 4:1, 8:1, 12:1, 16:1, 20:1 e 24:1) por 24h. A densidade do parasitoide não afetou a porcentagem de parasitismo e a emergência de T. diatraeae. O aumento da densidade de T. diatraeae reduziu a progênie, razão sexual, longevidade e a cápsula céfalica de fêmeas e machos desse parasitoide. A duração do ciclo de T. diatraeae foi proporcional ao aumento da densidade de suas fêmeas. O efeito da idade de pupas foi avaliado com estas isoladas com diferentes idades (24, 48, 72, 96, 120 e 144h) e expostas por 24h a oito parasitoides cada uma. A idade das pupas de D. hyalinata não afetou a porcentagem de emergência, o parasitismo, a razão sexual e a longevidade (fêmeas e macho) de T. diatraeae. O aumento da idade das pupas reduziu a descendência, ciclo de vida e a cápsula cefálica de T. diatraeae. No terceiro estudo, cada fase do desenvolvimento de D. hyalinata recebeu diferentes concentrações de óleos essenciais (canela, cravo, laranja) e do produto Azamax® (variando de 0,25% a 25%) diluídos em acetona e o controle teve, apenas, acetona. Discos de papel com 20 ovos foram pulverizados com cada material, utilizando-se quatro discos por tratamento, cada um representando uma repetição. Discos de folhas de abóbora foram imersos em cada tratamento e oferecidos às lagartas no terceiro estádio de D. hyalinata, com quatro repetições de 10 lagartas cada. Pupas dessa praga foram imersas por cinco segundos em cada um dos tratamentos, com quatro repetições de 10 pupas cada. As CL50 de 1,70; 0,97; 40,08 e 1,18 μL/ml para ovos, e 14,07; 48,92; 90,31 e 6,18 μL/ml para pupas e CL90 de 6,17; 2,38 e 648,50 e 15,67 μL/ml para ovos e 269,06; 642,23; 1079,63 e 16,08 μL/ml para pupas respectivamente, foram estimados para os óleos de canela, cravo, laranja e do produto Azamax®. Apenas a toxidade dos óleos de canela e cravo com valores para CL50 de 10,82 e 18,75 μL/ml respectivamente e CL90 para os óleos de cravo (46,21 μL/ml) e canela (37,21 μL/ml) foram estimados para lagartas de D. hyalinata devido à baixa mortalidade nos outros tratamentos até o tempo avaliado. Trichospilus diatraeae parasitou e produziu progênie em pupas de D. hyalinata e apresenta potencial para seu controle por não discriminar pupas por idade e até oito parasitoides por pupa são favoráveis para o desenvolvimento desse parasitoide. O produto comercial Azamax® mostrou potencial para o controle dessa praga. O óleo de canela foi mais tóxico nas fases de lagarta e pupa e o de cravo mais tóxico para ovos de D. hyalinata.
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Estudo do emprego de broca especial em substituição ao alargador na produção de furos em ferro fundido vermicular / Study on the use of special designed drill in replacement by reamer in the production of holes in compacted graphite cast ironReis, Alcione dos 10 April 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In many applications of metalworking industry it is required mass production of parts containing holes with finish and tolerances typically from precision assembling, with working quality, ISO IT grade, ranging from IT7- IT5. But to produce these holes with tighter tolerances and with low geometrical errors, conventional twist drills may be not enough, so further processes are required, like reaming for example. Before any reaming process comes the drilling process, resulting in two different tools, two parts on necessary machining time, which in turn affects productivity and competitiveness. Therefore , any investment in the production of tools and techniques to reduce the machining time of close tolerance holes without affecting the integrity of the surface and preferably at a lower cost , will receive special attention from the machining community. In this context, this paper presents a technical and economic study of the use of special designed drill in replacement by a reamer the production of cylindrical holes of 10 mm diameter pieces of compacted graphite cast iron in terms of finish, roundness and dimensional deviation. It was also investigated the influence of the allowance in the final quality of the machined hole reamer. The surface of the holes and the microhardness of the machined holes were also analyzed and the tool wear was monitored. Finally, the economic analysis of the tools employed was performed. The results showed that special drill resulted in finish and dimensional deviation as good as those produced by the reamer. IT6 was the working quality obtained after reaming with reaming allowance of 0.5mm, while IT8 quality was obtained by using the special designed drill. Wear on special drill was lower than that observed in the reamer, and for the latter chipping occurred. Up to 29% of reduction in machining time was achieved by using the special drill, which resulted in a reduction of 33% cost as well. In contrast the values of cylindricity deviations were higher than those obtained with the reamers under the conditions investigated. The hardness was not affected by the processes employed. / Em muitas aplicações da indústria metal-mecânica exige-se a fabricação de peças com furos que apresentem acabamento e exatidão geométrica necessária para a montagem de precisão, normalmente com qualidade de trabalho variando entre ISO IT5-IT7. Mas para a produção destes furos de tolerâncias mais estreitas e com menores erros geométricos, as brocas helicoidais convencionais não são suficientes, de forma que são necessários processos subsequentes, como o alargamento, por exemplo. Antes de qualquer operação de alargamento vem à operação de furação, chamada de pré-furação, e assim para um furo alargado são necessárias no mínimo duas ferramentas diferentes, duas parcelas no tempo de usinagem, que por sua vez afeta a produtividade e competitividade. Portanto, qualquer investimento na produção de ferramentas e técnicas que permitam reduzir o tempo de usinagem de furos de tolerância estreita, sem afetar a integridade da superfície e de preferência com menor custo, receberá especial atenção da comunidade de usinagem. Neste contexto, este trabalho apresenta um estudo técnico e econômico do emprego de broca especial em substituição ao alargador, na produção de furos cilíndricos, de 10 mm de diâmetro, em peças de ferro fundido vermicular, em termos de acabamento, cilindricidade e desvio dimensional. Investigou-se também a influência do sobremetal na qualidade final do furo usinado pelo alargador. As paredes dos furos e a microdureza dos furos usinados foram também analisados e o desgaste das ferramentas foi monitorado. Por último, foi realizada a análise econômica das ferramentas empregadas. Os resultados mostraram que a broca especial resultou em acabamento e desvio dimensionais tão bons quanto aqueles produzidos pelo alargador. IT6 foi á qualidade obtida pelo alargador após furação com sobremetal de 0,5 mm, enquanto que a broca especial produziu qualidade IT8. O desgaste da broca especial foi menor que aquele dos alargadores, sendo que para estes últimos ocorreu lascamento. Cerca de 29% de redução no tempo de usinagem foram obtidos com á broca especial, o que resultou em um custo de produção 33% menor. Em contrapartida os valores dos desvios de cilindricidade foram superiores aqueles obtidos com os alargadores nas condições investigadas. A microdureza não foi afetada pelos processos empregados. / Mestre em Engenharia Mecânica
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Caracterização de cascalhos de perfuração de poços de petróleo por técnicas analíticas instrumentais. / Characterization of petroleum well drill cutting by instrumental analytical techniques.Thais Bortotti Fagundes 13 April 2018 (has links)
O presente trabalho visou a caracterização dos cascalhos de perfuração de um poço de petróleo pertencente à Bacia de Santos, utilizando diferentes técnicas analíticas instrumentais. O enfoque foi dado a aplicação da difração de raios X como alternativa às práticas de estudo rotineiramente aplicadas na cabine de mud-logging, onde essencialmente são efetuadas classificações visuais das unidades litológicas do poço e geralmente em amostras de granulação fina, conferindo incertezas às descrições. Um total de 164 amostras de cascalhos foram analisadas quimicamente por espectroscopia por fluorescência de raios X e classificadas de acordo com suas similaridades mineralógicas utilizando o recurso de análise estatística multivariada de dados de difração de raios X. Esse recurso permitiu minimizar o conjunto de amostras para os estudos seguintes de caracterização. A definição e a quantificação dos minerais constituintes das amostras, assim como a determinação dos tamanhos e das formas das partículas por análise dinâmica de imagens foram efetuadas apenas em amostras representativas de cada um dos grupos de similaridades definidos. Os resultados foram comparados com os dados do perfil de acompanhamento geológico (dados de perfuração) e com as interpretações realizadas na cabine de mud-logging pelo geólogo, sendo identificada uma elevada correlação entre esses dados. A avaliação da viabilidade de utilização de difratômetros de bancada durante a etapa de perfuração de um poço de petróleo foi também verificada considerando o levantamento de procedimentos de preparação amostras viáveis de serem aplicados no local (tempo adequado de pulverização e eventuais erros de amostragem) e a qualidade das respostas obtidas por diferentes equipamentos de difração de raios X (condições de análise e resolução de picos). O uso de difratômetros de bancada no estudo de cascalhos de perfuração se mostrou viável do ponto de vista operacional, trazendo diversas vantagens para a correta caracterização dos fragmentos, com melhor acurácia nos resultados, diminuição das incertezas e se mostrando uma ferramenta muito ágil. / The present research aimed at characterization of the drill cuttings of an oil well belonging to the Santos Basin, using different instrumental analytical techniques. The main focus was given to the application of X-ray diffraction as an alternative to the routinely applied mud-logging study practices, where essentially visual classifications of the lithological units of the well are carried out and generally in fine granulation samples, giving uncertainties to the descriptions. A total of 164 samples of drill cuttings were chemically analyzed by X-ray fluorescence spectroscopy and classified according to their mineralogical similarities using the multivariate statistical analysis of X-ray diffraction data. This feature allowed minimizing the sample set for subsequent characterization studies. The identification and quantification mineral phases present in all samples, as well as the determination of the sizes and forms of the particles by dynamic images analysis, were carried out only in representative samples of each one of the defined groups of similarities. Results were compared with the data of the geological monitoring profile (drilling data) and the interpretations carried out in the mud-logging unit by geologist, and a high correlation between these data was identified. The viability of using a bench scale diffractometers during the drilling stage of an oil well was also studied considering the feasibility study on representative samples to be applied on site (adequate pulverization time and possible sampling errors) and quality of the results obtained by different X-ray diffraction equipment (collecting conditions and resolution of spikes). The use of bench diffractometers in the study of drill cutting proved to be feasible from the operational point of view, bringing several advantages for the correct characterization of the fragments, with better accuracy in the results, decrease of the uncertainties and a very agile tool.
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Melhoria da produtividade na obtenção de furos em liga de aluminio aeronautico com ferramentas de aço rapido / Improvement of the productivity in getting holes in aviation aluminum alloys with high speed toolsYamada, Yoshio 02 December 2010 (has links)
Orientador: Nivaldo Lemos Coppini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-15T08:50:52Z (GMT). No. of bitstreams: 1
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Previous issue date: 2010 / Resumo: O objetivo deste trabalho consiste em aperfeiçoar o processo de fabricação de furos realizados pela empresa X em um de seus produtos. Além da otimização deverá ser mantida a qualidade dimensional através do controle do diâmetro, da cilindricidade, da circularidade e do acabamento superficial de furos cilíndricos obtidos pelo processo de alargamento, com ferramentas de aço rápido em de liga de alumínio Al 7175 T66, para se obter furos com alta qualidade superficial e precisão de forma, que atendam as especificações de projeto de componentes da indústria aeronáutica. É estudada a influência das variáveis do processo: velocidade de corte, avanço, sobre as variáveis de resposta: força de avanço e momento torsor. O processo de alargamento estudado é realizado em 04 operações sendo 02 operações de furação e 02 operações de alargamento com ferramentas de aço rápido, na primeira etapa os ensaios foram realizados com os parâmetros de usinagem do processo produtivo para caracterizar o processo, na segunda etapa foi implementada uma elevação dos parâmetros de usinagem com uma redução do tempo de produção. Na terceira etapa os ensaios foram realizados para avaliar a influência do pré-furo e do pré-alargamento na qualidade final, acarretando em uma maior redução do tempo de processo comparado com o processo otimizado. Pretende-se obter tal furo com a realização de apenas uma etapa de furação e uma de alargamento. Para isso, é necessária a observação não só da qualidade das peças em relação aos requisitos exigidos pelos clientes, mas também do tempo de ciclo de produção. As condições otimizadas e resultantes foram: velocidade de corte 100 m/min., avanço 0,2 mm/rot., com operação de pré-furação e sem operação de pré-alargamento. Com estas condições reduziu-se o tempo de produção por peça de 1,42 min. para 0,63 min / Abstract: The purpose of this study is to optimize the manufacturing process of holes made by Company X in one of their products. Besides the optimization, should be maintained the dimensional quality by controlling the diameter, roundness, circularity, and surface finish of cylindrical holes obtained by the widening process, with high-speed steel reamers in a aluminum alloy 7175-T66, to obtain holes with high surface quality and precision of form that meet the design specifications of aviation industry components. It is studied the influence of process variables: cutting speed, feed, about the response variables: feed force and torsion moment. The widening process studied is realized in four operations, consisting of two drilling operations and two widening operations with high-speed steel tools. In the first stage, the tests were carried out with machining parameters of the company to characterize the process. In the second stage, was implemented an increase in machining parameters with a reduction in the production time. In the third stage, the tests were realized to evaluate the influence of pre-drilling and pre-widening on the final quality, resulting in a further reduction of processing time compared with the optimized process. We intend to obtain this hole with the realization of only one drilling stage and one widening stage. For this, it's necessary not only the observation of the quality of the pieces in relation to the requirements demanded by the customers, but also the cycle time of production. The optimized conditions and resulting were: cutting speed of 100 m/min., feed of 0.2 mm/rev, with pre-drilling operation and without pre-widening operation. With this conditions, reduced the production time per piece of 1.42 min. to 0.63 min / Mestrado / Engenharia de Fabricação / Mestre em Engenharia Mecânica
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Processo para obtenção de furos quadrados utilizando máquinas ferramentas CNC com ferramenta em rotação / Process to get square holes by machine tools CNC with tool in rotationCastro, Marcelo Hirai 21 August 2018 (has links)
Orientador: Amauri Hassui / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-21T02:13:50Z (GMT). No. of bitstreams: 1
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Previous issue date: 2012 / Resumo: A inovação é a chave para o diferencial da indústria no mercado competitivo atual. Fazer diferente, melhor e mais barato sempre agrega valor ao produto. Por outro lado, a resistência às mudanças faz parte do comportamento humano, seja na sociedade, ou na indústria. O objetivo principal deste trabalho é estudar a viabilidade de se fazer furos não cilíndricos com uma ferramenta em rotação utilizando máquinas-ferramenta CNC. Estes sempre foram obstáculos na indústria de fabricação pela dificuldade de obtenção. Sendo assim, o processo apresentado nesse trabalho busca usinar um furo quadrado com a mesma configuração de ferramentas e fixação de peças utilizadas para um furo cilíndrico, tão comum à indústria. Isso visa reduzir custos de fabricação e facilitar a obtenção de furos não cilíndricos com os recursos de equipamentos programáveis existentes no chão de fábrica. A partir de um modelo matemático, a máquina é programada para executar movimentos sincronizados entre a rotação e os deslocamentos do eixo da ferramenta. Diversas programações foram testadas em diferentes máquinas ferramenta CNC, com diferentes comandos, com e sem recursos de alta velocidade, com diferentes quantidades de pontos programados, interpolações lineares e circulares. A partir dos experimentos, foram analisadas as configurações das máquinas, a capacidade de execução do controlador numérico instalado, a velocidade desenvolvida pela máquina na operação e a geometria obtida dos furos quadrados. Os experimentos apontam que para executar o furo quadrado, os comandos devem ser capazes de controlar um eixo rotativo como eixo propriamente dito, além de sincronizarem mais três eixos lineares. O crítico para este tipo de operação é a velocidade desempenhada pela máquina, sendo o fator mais significativo, o tempo que o comando precisa para o processamento do bloco de programação, independentemente da ativação de recursos de alta velocidade, interpolações lineares ou circulares. Verificou-se também que quanto maior a quantidade de pontos para compor a trajetória do centro da ferramenta, melhor será a geometria obtida do furo. Sendo assim, as máquinas ferramenta CNC que estão em operação na indústria são capazes de realizar a furação não cilíndrica de forma muito próxima à furação cilíndrica quanto ao tempo de usinagem e ao sistema de fixação da ferramenta e da peça, sendo necessária uma programação sincronizada do eixo spindle presente em toda e qualquer máquina ferramenta / Abstract: The innovation is the key for the differential of the industry on the competitive market nowadays. To make different, better and cheaper always it is worth a lot to the product. By the other side, the resistance to changes makes part of the human behavior, in society, or in the industry. The main goal of this work is to study the feasibility to machining of non-cylindrical holes by a tool in rotation using CNC machine tools. That always has been offering obstacles to manufacturing industry by the difficulty of fabrication. Thus, the process presented on this work will machining a square hole with the same configuration of tools and systems for fixation of the parts, used for a cylindrical drilling, so common to industry. This intends to reduce the costs of fabrication and make easier to get non-cylindrical drilling using resources of the programmable equipment which are working at the shops. From a math model on, the machine is programmed to execute synchronized movements between the rotation and the displacements of the axis of the tool. Different programs were tested in different CNC machine tools, with different controllers, with and no resources for high speed, with different quantity of programmed points, with linear and circular interpolations. From the experiments, it was analyzed the configuration of the machines, the capacity for execution of the controller installed, the speed developed by machine at the operation and the geometry of the square holes. The experiments show that to machine a square hole, the controllers must be able to control a rotating axis itself, beyond to synchronize three axis. The critical to this kind of operation is the speed developed by the machine, being the most significant factor, the time the controller needs to process the block of programming, independently the activation of resources for high speed, linear or circular interpolations. It was verified than as larger the amount of points to compose the trajectory of the center of tool, better will be the geometry of the hole. Thus, the CNC machine tools in operation in the industry are able to machine the non-cylindrical drilling in a way very closely the cylindrical drilling as the time of machining and the fixing system of the tool and parts, requiring a programming that synchronizes the main spindle installed in any machine tool / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica
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Dynamics of the British Ice Sheet and prevailing hydrographic conditions for the last 175,000 years : an investigation of marine sediment core MD04-2822 from the Rockall TroughHibbert, Fiona Danielle January 2011 (has links)
This study presents a stratigraphic investigation of the marine sediment core MD04-2822 from the Rockall Trough (56° 50.54' N, 11° 22.96' W; 2344 m water depth). This core is currently the only available high resolution record for the calibration of Late Quaternary sedimentary sequences of the British (Hebridean) margin. It therefore offers an unprecedented archive of changing sedimentological and climatological conditions for the last 175,000 years. The high resolution, multi-proxy records have enabled surface and deep water conditions within the Rockall Trough to be reconstructed. In addition, the fluctuating nature of ice-rafted debris (IRD) inputs to the MD04-2822 site allows a first order attempt of BIS dynamics for the entirety of the last glacial period (i.e. from the demise of the last interglacial to the decay of the Devensian/Weichselian ice sheet) as well as the majority of the penultimate (Saalian/MIS 6) glaciation. Sediment core MD04-2822 is ideally located to capture the dynamics of the British Ice Sheet (BIS) via a continuous record of IRD and fine-grained terrigenous inputs. Fundamental to this is the construction of a robust chronology. This was achieved via: the correlation of the benthic δ¹⁸O record to a global δ¹⁸O stack (SPECMAP); the correlation of the surface proxies (% N. pachyderma (sinistral) and XRF Ca) to the Greenland δ¹⁸O and Antarctic methane ice core records; and radiocarbon dating. This chronology was validated using both radiocarbon dating and tephra horizons. An evaluation of the event stratigraphy approach used in the construction of the MD04-2822 chronology is presented. The marine record provides a valuable archive of past ice sheet dynamics as much terrestrial evidence is removed or obscured by subsequent ice sheet oscillations MD04-2822 provides the first evidence for the expansion of the BIS onto the Hebridean Margin during MIS6 (thereby confirming previous long-range seismic correlations). The continuous sedimentation at MD04-2822 enabled the first insights into the early dynamics of the last BIS. Increases in IRD and fine grained terrigenous material delivered to the MD04-2822 at ca. 72 kyr represent the first significant delivery of material from the BIS across the continental shelf to the core site. The BIS would therefore have attained a marine calving margin by this time. A multi-proxy investigation of provenance was undertaken, however unequivocal provenance determinations remain problematic. The location of the core suggest the proximal BIS as the most likely source of terrigenous inputs. The expanded nature of the MD04-2822 sediments during the penultimate deglacial (Termination II) provides the first details of BIS dynamics for this period: the interplay of large inputs of freshwater from the decay of the Saalian (MIS 6) ice sheets (including the BIS) upon the surface and deep water circulation of the North Atlantic is investigated. In addition, sub-orbital climatic variability is documented at this location throughout the last interglacial (MIS 5e) and appears to be an intrinsic feature of both the N.E. Atlantic surface and deep water circulation of the last 175 kyr.
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Borrhålslängder vid pallbrytning : Undersökning om önskade borrhålslängder kan erhållas vid produktionsborrning i dagbrottMitander, Eva, Hauri, Oskar January 2017 (has links)
I Aitiks dagbrottsgruva i norra Lappland bryts kopparmalm med hjälp av metoden pallbrytning. I korthet innebär det att omkring 200 borrhål borras vertikalt i berget och fylls senare med sprängämne. Vid detonationen frigörs en horisontell skiva, så kallad pall, från det omgivande berget. Aitik använder i dagsläget sin borrplan för bestämning av borrhålens längd. Emellertid överensstämmer inte alltid dessa längder med de önskvärda borrhålslängderna. Målet med projektet var att föreslå förbättrade metoder och tillvägagångsätt för att nå önskad nivå vid produktionsborrning. Under projektet har det studerats hur mycket borrplanen avviker från önskade borrhålslängder. Det har också undersökts i vilken utsträckning borrmaskinerna autonomt klarar av att beräkna korrekta hål-längder med hjälp av sitt navigationssystem. En borrmaskin i Aitik använder Trimbles navigationsplattform medan de övriga fyra använder Leica. Analyserna visade att Trimbles navigationssystem var mycket tillförlitligt att använda för hål-längdsbestämning, förutsatt att noggrann kalibrering utförts. Leicas navigationssystem visade sig vara mindre tillförlitligt, då det ”svajade” i höjdled: för samma punkt i rummet visades olika höjdledskoordinater vid olika tidpunkter. Den Leica-utrustade borrmaskinen som svajade mest hade variationsbredden 31,9 cm. Rekommendationerna är: * Att om borrplanen fortsättningsvis ska användas för hållängdsbestämning, rekommenderas att ”nollning” av borrmaskinen skall ske utan rotation. Nollning är den punkt som bestäms till borrstartspunkt under borrningens utförande. Våra tester visade att om nollning sker med rotation, kan borrkronan sjunka ned 20 cm i pallytan innan borrstart registreras. På grund av detta kan borrhålen bli för långa. * Att under en testperiod, låta navigationssystemet på maskinerna autonomt beräkna borrhålens längd. Under denna period bör regelbundna kontroller av navigationssystemet ske, för att säkerställa att höjdkoordinaterna håller sig inom bestämda gränser. Kontrolleras maskinernas navigationssystem regelbundet kan ett stort statistiskt underlag skapas, vilket kan användas vid ett långsiktigt beslut om navigationssystemet fortsättningsvis skall användas för bestämning av borrhålslängder. / In the open pit mine Aitik, situated in the north of Lapland, copper ore is mined using the method pallet mining. In short, around two hundred boreholes are drilled vertically into the rock and subsequently filled with explosives. At detonation, a horizontal slice called a pallet is released from the surrounding rock. Today Aitik uses a drilling plan to decide the lengths of the boreholes. However, these lengths do not always correspond with the desired borehole lengths. The goal with the project was to find and suggest better methods and approaches to achieve desired levels of production drilling. During the project, studies have been made to see how much the drilling plan differs from the desired borehole lengths. The studies have also concerned the extent to which the drilling machines can make autonomic decisions determining the borehole lengths, using their navigation system. One drilling machine in Aitik uses a Trimble platform for navigation, while the other four use Leica. The analysis shows that the Trimble navigation platform was very reliable in deciding borehole lengths, provided that an accurate calibration was performed. The Leica navigation system turned out to be less reliable, since its height readings fluctuated: the same point in space would show as different coordinates of height at different points in time. The Leica-equipped power drill with the most fluctuation had a variation width of 31,9 cm. The recommendations are: * That, in the case of continuous use of the drill plan to determine borehole length, the “zero setting” of the power drill shall be made without drill rotation. The zero setting is starting point of the drilling operation. The tests showed that if the zero setting is done with rotation, the drill crown can sink 20 cm down into the pallet surface before drill start is registered. Because of this, the drilling holes can become too long. * That, during a test period, the navigation systems of the machines shall autonomously calculate and decide the borehole length. During this period, regular controls of the navigation systems should be made to ascertain that the coordinates of height remain within certain limits. Regular controls of the navigation systems can provide large amounts of statistical data, which can be used to make a long-term decision whether the navigation systems should continue to determine the borehole lengths.
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Classification of Drill Core Textures for Process Simulation in Geometallurgy : Aitik Mine, SwedenTiu, Glacialle January 2017 (has links)
This thesis study employs textural classification techniques applied to four different data groups: (1) visible light photography, (2) high-resolution drill core line scan imaging (3) scanning electron microscopy backscattered electron (SEM-BSE) images, and (4) 3D data from X-ray microtomography (μXCT). Eleven textural classes from Aitik ores were identified and characterized. The distinguishing characteristics of each class were determined such as modal mineralogy, sulphide occurrence and Bond work indices (BWI). The textural classes served as a basis for machine learning classification using Random Forest classifier and different feature extraction schemes. Trainable Weka Segmentation was utilized to produce mineral maps for the different image datasets. Quantified textural information for each mineral phase such as modal mineralogy, mineral association index and grain size was extracted from each mineral map. Efficient line local binary patterns provide the best discriminating features for textural classification of mineral texture images in terms of classification accuracy. Gray Level Co-occurrence Matrix (GLCM) statistics from discrete approximation of Meyer wavelets decomposition with basic image statistical features[PK1] (e.g. mean, standard deviation, entropy and histogram derived values) give the best classification result in terms of accuracy and feature extraction time. Differences in the extracted modal mineralogy were observed between the drill core photographs and SEM images which can be attributed to different sample size[PK2] . Comparison of SEM images and 2D μXCT image slice shows minimal difference giving confidence to the segmentation process. However, chalcopyrite is highly underestimated in 2D μXCT image slice, with the volume percentage amounting to only half of the calculated value for the whole 3D sample. This is accounted as stereological error. Textural classification and mineral map production from basic drill core photographs has a huge potential to be used as an inexpensive ore characterization tool. However, it should be noted that this technique requires experienced operators to generate an accurate training data especially for mineral identification and thus, detailed mineralogical studies beforehand is required. / Primary Resource Efficiency by Enhanced Prediction (PREP) / Center for Advanced Mining and Metallurgy (CAMM)
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