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Artykuły w czasopismach na temat "Forage percussif"
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Pereira, Helen Batista Menezes, Joyce Ferreira do Nascimento, Carina Printes Lobato, Mariana Silveira Brasil, Silas Fernandes Goes, Gabriela de Figueiredo Meira, Luana Pontes Barros Lopes i André Luiz Cabral da Silva. "Tratamento endodôntico em dente com rizogênese incompleta com a utilização do hidróxido de cálcio: Relato de caso". Research, Society and Development 10, nr 16 (19.12.2021): e579101624416. http://dx.doi.org/10.33448/rsd-v10i16.24416.
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Objetivo: O objetivo deste trabalho é apresentar um caso clínico de tratamento endodôntico em dente com rizogênese incompleta e necrose pulpar através de técnica de apicificação, utilizando medicação intracanal com hidróxido de cálcio durante 1 ano de tratamento, obtendo resultados favoráveis. Metodololgia: Partindo da permissão da paciente por meio do Termo de Consentimento Livre e Esclarecido em partilhar sua imagem para devido fim, o presente estudo trata de um relato de caso clínico de cunho analítico descritivo (Pereira et al., 2018). Relato de caso: Paciente L. V., sexo feminino, 08 anos de idade, leucoderma, compareceu na clínica odontológica da Faculdade (Fametro), acompanhada por sua responsável. Na anamnese a mãe da paciente relatou que a filha sofreu uma queda da própria altura fraturando o incisivo central superior com exposição pulpar. No exame complementar radiográfico foi observado lesão perirradicular de origem endodôntica no elemento 11 e 12, formação radicular incompleta com forame aberto no estágio 8 de Nolla. Foi realizada a percussão vertical com espelho clínico indicando resposta positiva, necrose pulpar e o elemento 11 apresentava mobilidade de grau II. Considerações Finais: Diante do relato de caso clínico apresentado, pôde-se observar a importância da terapia endodôntica para preservação e manutenção do elemento dental com rizogênese incompleta e necrose pulpar, contudo, a terapia de apicificação, com hidróxido de cálcio utilizado por décadas, levou a resolução dos sintomas, reparo dos tecidos envolvidos e induziu o fechamento apical atuando positivamente na desinfecção do canal radicular.
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"Taux de forage des forets de percussion rotative et caractéristiques de la roche". Journal of Terramechanics 25, nr 3 (styczeń 1988): 239. http://dx.doi.org/10.1016/0022-4898(88)90007-9.
Pełny tekst źródłaRozprawy doktorskie na temat "Forage percussif"
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Aldannawy, Houssam Aldine. "Le forage percussif en conditions extrêmes : expérimentations et modélisations numériques". Electronic Thesis or Diss., Université Paris sciences et lettres, 2022. http://www.theses.fr/2022UPSLM043.
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Le forage percussif est une technologie qui consiste à appliquer une série d’impacts dynamiques conduisant à la fragmentation de la roche par deux mécanismes principaux : l’écrasement et l’écaillage. Ces mécanismes sont fortement influencés par de nombreux facteurs qui ont fait l’objet d’investigations expérimentales et numériques pendant cette thèse. Un dispositif expérimental a été développé pour réaliser des essais d’impacts dynamiques. Un système de mesure précis a été également mis au point afin d’avoir les résultats des nombreuses séries d’essais qui ont été menées dans le cadre de cette thèse. Quant au volet numérique, un laboratoire virtuel a été construit en se basant sur un modèle rhéologique élasto-viscoplatique validé sur des essais de laboratoire pour décrire le comportement du granite et un mécanisme de contact pour simuler l’interaction insert-roche pendant un impact dynamique. Dans un premier temps, plusieurs études paramétriques ont été réalisées sur un matériau homogène. Dans un deuxième temps, une nouvelle approche de modélisation de l’hétérogénéité a été développée pour décrire la distribution des minéraux dans le granite.Ces études ont fournis des éléments primordiaux pour la compréhension des mécanisme physiques de destruction des roches dures en percussion, pour l’évaluation des effets des principaux paramètres et facteurs de forage et pour l’optimisation de l’outil de foragePercussive drilling is a technology that consists in applying a series of dynamic impacts leading to the rock fragmentation by two main mechanisms: crushing and chipping. These mechanisms are highly influenced by many factors on which experimental and numerical investigations were carried out in this thesis. An experimental set up was developed to carry out dynamic impact tests. Several series of tests were realized and their results were measured using a precise measurement system which was also developed during the thesis. As for the numerical work, a virtual laboratory was built based on an elasto-viscoplastic constitutive model validated on laboratory tests to describe the granite behavior and a contact mechanism to simulate the insert-rock interaction during a dynamic impact. First, several parametric studies were carried out on a homogeneous material. Secondly, a new heterogeneity modeling approach was developed to describe the distribution of minerals in the granite. These studies have provided essential elements for understanding the physical mechanisms of hard rocks destruction in percussion, for evaluating the effects of the main drilling parameters and factors and for optimizing the drilling tool
Książki na temat "Forage percussif"
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Instant Sound Forge. San Francisco, CA: CMP Books, 2004.
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Park, Chan E., Adnan Hossain, William Grange, Judith Fletcher, Domenico Pietropaolo, Hanne M. de Bruin, Josh Stenberg i in. Korean Pansori as Voice Theatre. Bloomsbury Publishing Plc, 2023. http://dx.doi.org/10.5040/9781350174917.
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This book introduces readers to the historical, performative, and cultural context of pansori, a traditional Korean oral story-singing art. Written by a scholar-practitioner of the form, this study is structured in three parts and begins by introducing readers to the technical, aesthetic, and theoretical components of pansori as well as the synthesis of vocal and percussive elements that stage the narrative. It also reflects on the historical contexts of pansori alongside Korea’s transformation from Joseon monarchy to modern statehood. It argues that with colonial annexation came modernist influences that Korean dramatists and audiences used to create distinct new genres of Korean performance, using the common thread of pansori. It further explores the dynamic interplay of preservation and innovation, beginning in the post-war designation of national performance art and continuing with developments that coincide with Korea’s imprint on cultural globalization. Along with Korea’s growth as a world economic center, a growing enthusiasm for Korean culture around the world has increased the transmission and visibility of pansori. Chan E. Park argues that tradition and innovation are not as divergent as they are sometimes imagined to be and that tradition is the force that enables innovation. Unique among treatments of this subject, this book is written from combined researcher and practitioner perspectives. Drawing on her ethnographic work and performance practice, Chan E. Park interweaves expert knowledge of both the textual and performative aspects of the form, rendering legible this dramatic tradition. Pansori as voice theatre examines the practice of pansori, Korean oral storysinging, in its historical, performative, and cultural context. There are three sections to the text. Section One analyzes technical, aesthetic, and theoretical components of pansori. Using translated samples, the book explicates the synthesis of vocal and percussive elements that, together with the listening ear, stage the narrative. Section Two critically reflects on the historical contexts of pansori alongside Korea’s transformation from Joseon monarchy (1391-1910) to modern statehood. In the case of pansori tradition, the posited strict class hierarchies of Joseon were in fact porous, as attested by the patronages and collaborations over generations. With colonial annexation (1910-1945) came modernist influences that Korean dramatists and audiences localized into distinct new genres of Korean performance using the common thread of pansori. Section Three examines the dynamic interplay of preservation and innovation, beginning in the post-War designation of national performance art (gugak) and continuing with off-mainstream, fusion, and hybrid developments that coincide with Korea’s imprint on cultural globalization (hallyu). Along with Korea’s growth as a world economic center (late twentieth century to present), a growing enthusiasm for Korean culture around the world has increased the transmission and visibility of pansori through institutions of popular culture. Ultimately, tradition and innovation are not as divergent as they are sometimes imagined to be. Rather, a study of pansori suggests that tradition is the centripetal force that enables innovation for the collective theatrical imagination.
Części książek na temat "Forage percussif"
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Glocker, Christoph. "Percussion Drilling Machine". W Set-Valued Force Laws, 183–93. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-540-44479-4_13.
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Allen, Ray. "J’Ouvert in Brooklyn". W Jump Up!, 207–34. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190656843.003.0009.
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Chapter 8 describes the emergence of Brooklyn’s J’Ouvert celebration in the 1990s. With its steelband and percussion-only policy, which strictly forbade deejays and amplified bands, J’Ouvert reflected a conscious attempt to preserve and revitalize older Carnival musical practices as forms of cultural heritage in response to their near disappearance from the more commercial Eastern Parkway parade. This chapter will flesh out the emergence of Brooklyn J’Ouvert, focusing on how a group of Trinidadian migrants revived a century-old celebration to create an event that appeared to some to actually be “more authentic” than what was going on back in Trinidad at the time. It is an extraordinary story of cultural revitalization within Brooklyn’s Caribbean community. Brooklyn J’Ouvert was derived from its parent Trinidad celebration, but like many diasporic expressions, it took on a life of its own.
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Lapidus, Benjamin. "Strings and Skins". W New York and the International Sound of Latin Music, 1940-1990, 54–81. University Press of Mississippi, 2020. http://dx.doi.org/10.14325/mississippi/9781496831286.003.0002.
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This chapter outlines the important history and role of craftsmen based in New York City who produced and repaired traditional instruments used in the performance of Latin music. It introduces individuals who came from Cuban, Puerto Rican, Dominican, and Jewish communities, and examines how their instruments physically represented the actual sound of Latin Music to New York and the world on widely disseminated recordings. Many of these instrument makers also sold their instruments beyond New York City and the United States. The chapter also discusses the work of builders and musicians in New York City to create and modify the tools used to forge the sound of Latin music and diffuse both the instruments and their aesthetic throughout the world. Ultimately, the chapter seeks to unify into one coherent narrative, the efforts of folklorists, journalists, and authors who paid attention to the origins of hand percussion instruments in New York, their subsequent mass production, and the people who built the instruments used to play Latin music in New York City.
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Braga, Sandro Moreira, Erbert Costa Lopes i Antônia Lidiane de Sousa Leitão. "CONTRIBUIÇÃO PARA INTERPRETAÇÃO DO PROCESSO DE SONDAGENS A PERCUSSÃO MECANIZADA PARA PROJETOS DE FUNDAÇÕES". W Geotecnologias: análises, técnicas e aplicações em pesquisa, 46–63. Editora Científica Digital, 2024. http://dx.doi.org/10.37885/240115595.
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O SPT (“Standard Penetration Test”) é o ensaio de campo mais largamente utilizado em engenharia geotécnica em todo o mundo, graças a sua simplicidade, baixo custo e a obtenção de informações cuja aplicação foi consagrada em métodos empíricos e semi-empíricos de projeto. Apesar das críticas à falta de conformidade às normas por parte de alguns executores do ensaio e à pouca racionalidade de alguns dos métodos de uso e interpretação dos resultados obtidos, este ainda é o processo mais adotado na prática da engenharia de fundações do País. Desta forma, inicialmente a pesquisa tinha o objetivo apresentar resultados das sondagens feitas para execução de 15 passarelas de pedestres sobre as Rodovias Federais do Departamento Nacional de Infraestrutura de Transportes (DNIT), no estado do Ceará, totalizando a execução de 127 ensaios SPT realizados em sondagens a percussão, sendo 82 ensaios de SPT obtido da maneira manual usual (NBR 6484) e 45 ensaios de SPT obtidos com martelo automático hidráulico, de queda livre, nas perfurações mecanizadas, visando a compará-los e estabelecer correlações entre os valores do Nspt obtidos. Entretanto, com base no experimento realizado (o estudo de caso ficou limitado a Passarela nº 18), foram feitas correlações entre as sondagens SPT manual e SPT mecanizada, com seus respectivos coeficientes de determinação (R²) e correlação (r), tudo classificado segundo Dantas (1998), correções de energia e os parâmetros relacionados com a deformabilidade e resistência dos solos.
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Afzali, Behdad, i Rupert P. M. Negus. "Abdomen". W The Pocketbook for PACES. Oxford University Press, 2012. http://dx.doi.org/10.1093/oso/9780199574186.003.0011.
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The abdominal station in MRCP PACES should be a ‘set piece’ that can be approached with confidence. You are likely to encounter patients with chronic stable disease such as chronic liver disease, haematological malignancy with associated hepatosplenomegaly and chronic kidney disease, particularly those undergoing some form of renal replacement therapy, for instance dialysis or transplantation. Signs in the abdomen are generally straightforward to elicit and the commonest obstacles to passing are poor presentation or a failure to put the features together in a logical fashion. Many diagnostic findings in the abdominal station can be identified by inspection alone, so particular attention should be paid to adequate exposure and the identification of extra-abdominal signs (e.g. multiple spider naevi of chronic liver disease, telangiectasia of hereditary haemorrhagic telangiectasia and xanthelasmata in primary biliary cirrhosis). Do not forget to have a good look at the back as important signs may be restricted there (e.g. spider naevi or posterior nephrectomy scars). During the observation phase, attention should be paid to the nutritional status of the patient and to any other available clues (for instance, one of the authors, BA, diagnosed bilateral adrenalectomies from a medic alert bracelet at the bedside in his MRCP exam). The presence of abdominal scars is very useful as they usually overlie the organs that have been surgically handled. Whist surgery is frequently concerned with resecting parts or the whole of organs, remember that organs, including kidneys, pancreas and liver, may also be transplanted. As a result of a detailed end-of-the bed examination, sufficient information may be garnered to allow a diagnosis to be formulated, with subsequent palpation, percussion and auscultation, simply confirming the suspected diagnosis. Keep to a well-practised order to produce a fluid display which you should be able to complete in around 5 minutes. 1. Introduce yourself to the patient and lie them down if this has not already been done. Ask if there is pain or tenderness anywhere. 2. Inspect the patient from the end of the bed. Ensure that you look for any additional clues, such as those around the bedside.
Streszczenia konferencji na temat "Forage percussif"
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Peltokangas, Suvi, Sirpa Launis, Markus Saarela i Jouni Mattila. "Modeling and Simulation of a Hydraulic Drill for Control System Design Purposes". W ASME/BATH 2017 Symposium on Fluid Power and Motion Control. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fpmc2017-4290.
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In rock excavation processes, hydraulic rotary-percussive drilling is used for drilling and blasting in both surface and underground drilling operations. A hydraulic percussive drilling system is composed of percussion, rotation, feed, and flushing functions. In this paper, we detail the interaction of feed and rotation functions using a rock model. The feed actuator is a cylinder drive and a hydraulic motor actuator rotates the drill bit. The feed is force controlled and rotation is torque controlled by a feed reduction valve acting on the pressure compensator of the mobile hydraulic proportional directional control valve. In addition, in this work an individual load sensing variable displacement pump is used for both hydraulic functions. A suitable rock model is developed and verified against a measurement set. The inputs of the rock model are percussion drill flow rate, percussion pressure, feed force, and rotation torque, and the outputs are drill bit penetration rate and rotational speed. The modeling work is carried out to enable intelligent rock drilling control system development for changing rock conditions. The simulation results obtained verify that the simple rock model emulates various rock characteristics ranging from extremely hard rock like granite to softer minerals and that the changes in drilling parameters were as expected.
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Sun, Zhaowei, Xiaoguang Wu, Rui Yang, Zhongwei Huang, Huaizhong Shi, Zongjie Mu i Huiyong Yu. "Numerical Analysis on Characteristics of Cracks and ROP Enhancement Performance in Hard Rocks Subjected to Axial-Torsional Coupled Percussion". W 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0347.
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ABSTRACT Axial-torsional coupled percussive drilling (ATCPD) is a practical technique for creating volumetric breaking patterns and increasing rate of penetration (ROP) of hard rocks. Our paper focus on numerical investigations on ATCPD process. We employed a continuous-discrete coupling method based on cohesive elements to characterize the rock failure subjected to different percussion (axial, torsional and coupled percussion). Based on this model, the penetration-cutting process of the single cutter at different percussion modes was simulated, respectively. The corresponding cracks characteristics, penetration/cutting force and torque were analyzed. Rock scratch experiments were further conducted on granites to validate the model. The results show that the complex cracks propagation zone and the larger tensile cracks around the cutter are developed subjected to coupled percussion, resulting in larger failure elements number and cracks volume. That is, more significant macro damage is thought to form in coupled percussion, thereby increasing the penetration and cutting force of single cutter. It is worth noting that the coupled percussion mode can also generate stable fluctuation torque, which improves the ROP enhancement performance. Our results are expected to provide some guidance for efficient drilling in hard rocks. INTRODUCTION Increasing oil, gas, and heat reserves in deep formations will be critical in addressing the worldwide energy supply (Santos et al., 2000; Moore and Simmons, 2013; Hu et al., 2013). The construction of wells to exploit deeper energy in more challenging environments requires large investments, which are mainly related to the involved drilling operations (Abdo and Haneef, 2013; Diaz et al., 2017). For example, the reliance on drilling costs is especially high in the development of enhanced geothermal system (EGS), primarily because this method of obtaining geothermal energy necessitates the challenge of drilling deep holes in hard crystalline basement rocks, such as granites (Song et al., 2018; Anderson and Rezaie, 2019). These limiting factors pose a major challenge to our traditional drilling technologies (e.g. rotary drilling), whose poor performance in hard rocks, in terms of wearing of the drill bits and low penetration rates (Diaz et al., 2017; Rossi et al., 2020). As a result, the development of drilling techniques to increase the ROP enhancement effect in deep reservoir hard rocks has attracted more and more interest in the engineering field.
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Quan, Qiquan, S. Li, S. Jiang, X. Hou i Z. Deng. "Control of Drilling and Coring Device Based on Online Identification". W ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62804.
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This paper presents a drilling and coring device for the lunar exploration, which is possibly utilized to acquire the lunar regolith with a certain depth. The drilling device is composed of three components: rotary unit, percussive unit and penetrating unit. The rotary-percussion drill can work in two different operating modes: rotary mode and rotary-percussive mode, depending on the properties of cut object. In the relatively loose regolith, rotation and penetration can make the drill work in a well state. However, once rock is encountered in the drilling process, besides rotation and penetration, percussion must be launched to reduce the drilling power and the required penetrating force. Due to the indetermination of the lunar environment, it is not easy to control the coring drill to adapt to the encountered conditions. To obtain a high coring ratio with relatively low power, an intelligent drilling strategy is inevitably proposed to accomplish the drilling process control. Considering the lunar soil simulant should cover the possible composition of real lunar soil, simulant are classified into several levels based on the generalized drillability. For each level of drillability of lunar soil simulant, experiments are conducted to get the characteristics in frequency-domain of rotary torque output. The sampled characteristics of rotary torque output are utilized to train the object-recognition system based on Support Vector Machine (SVM). Information in all the levels of drillability of lunar soil simulant is stored in the object-recognition system as an expert system. To understand the properties of the drilling object, rotary torque is selected to identify the level of drillability of simulant in drilling process. Subsequently, once the level is obtained, drilling strategy is adjusted to adapt to the current level correspondingly in real time. Experiments are conducted to verify the intelligent drilling strategy successfully.
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Fang, Zhou, Gang Wu, Ce Song, Jun Yuan i Zhe Wang. "Study on the Mechanical Response of Gas Cylinders Under Shock Load". W ASME 2023 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/pvp2023-107108.
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Abstract In order to ensure the safe operation of pressure vessel cylinders in the service stage, the mechanical response law of gas cylinders under dynamic load under different working conditions is clarified. In this study, numerical simulation was used to study the different shock loads of gas cylinders at different positions. The finite element analysis results of the impact load of the cylinder when the sphere and cone are used as the percussive objects are compared and analyzed, and it is concluded that the steel cylinder will cause obvious deformation of the cylinder as a whole when subjected to the impact load, and the maximum deformation position is located at the top head or the connection between the top head and the cylinder. Because of the presence of the saddle, the shock load acts on the bottom head, and the equivalent force distribution is mainly distributed in the lower half of the cylinder. When acting on the cylinder or the connection between the cylinder and the top head, the equivalent force is distributed throughout the cylinder, but regardless of where the shock load is applied, the maximum equivalent force occurs at the connection between the cylinder and the saddle, where the stress concentration is generated. The cylinder bears the impact load applied by different percussive objects, the incidence speed increases, the maximum deformation and equivalent force generated by the cylinder increase, and there are also certain differences in the value when the cylinder bears the impact load applied by the sphere and the cone, indicating that when the cylinder bears the impact load, the type of percussion has a certain impact on the equivalent force of the cylinder.
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Ji, Ran, Huaizhong Shi, Zhaowei Sun, Han Chen, Chao Xiong i Hengyu Song. "Characteristics of Conicl Diamond Tooth for Breaking Hard Rock Under Vibratory Percussion". W 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0637.
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ABSTRACT The application of conicl PDC teeth to vibratory percussion drilling technology is expected to break deep hard rock efficiently and improve drilling efficiency. In this paper, the characteristics of conicl diamond tooth cutting and hard rock under percussion are investigated. Firstly, experiments on percussion compression of conicl diamond tooth into the broken rock were carried out to analyse the percussion energy and the characteristics of rock crushing pits. Secondly, a numerical model of the cutting process of conicl diamond tooth under the vibratory percussion was established. Three stages of rock-breaking by conical tooth cutting under high frequency number percussion are analyzed. Stress peaks with percussion of 6 times increased by 36.8% and 25.5% compared with percussion of 0 times and percussion of 3 times. There is the highest point of rock-breaking efficiency between percussion of 3 times and 4 times. Cutting force with percussion amplitude of 1.5mm increased by 42.7% compared with percussion amplitude of 0mm. The rock-breaking specific energy with percussion amplitude of 1.5 mm increased by 32.4% compared with percussion amplitude of 0 mm. This study provides a theoretical basis for the use of conical tooth in PDC drill bits under percussion. INTRODUCTION In the oil and gas exploration and development industry, drilling cost accounts for a large proportion of the overall development cost. The application of efficient drilling technology directly affects the final benefit(Wang, 2003)i. The exploration and development of deep and ultra-deep wells has become the focus of current attention(Meiling et al., 2014)ii and conventional drilling methods are increasingly unable to meet the needs of efficient drilling. As the well depth increases, the hardness and plasticity of the rock increases and the drillability decreases, which also increases the difficulty of drilling in deep hard formations. How to improve ROP has become one of the key issues in drilling engineering technology research. Previous studies have shown that vibratory percussion drilling can significantly improve rock breaking efficiency in hard rock(Hustrulid, 1971;Li et al.,2020;Pavlovskaia et al.,2015)iii.
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Hatman, Victor G., Imtiaz Haque i Amit Bagchi. "Dynamics of a Flexible Rotating Beam Under Percussive and Constrained Motion". W ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0714.
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Abstract This paper presents a dynamical and computational model for the analysis of the interaction of a flexible Euler-Bernoulli beam attached to a uniformly rotating hub, and a flat rigid surface, parallel to the axis of the hub. The dynamic model is derived using Lagrange’s equations in conjunction with an eigenfunctions-generalized-coordinates based representation of the displacement fields. It is shown that one must account for the longitudinal displacements if dynamical stiffening is to be observed. A quadratic approximation for these displacements is used and a computationally effective way of by-passing the calculation of the volume integrals at every integration step, by matrix-vector multiplications is implemented. The energy dissipating constraint, which requires the tip of the filament to move on the surface is imposed with a Lagrange multiplier and a generalized friction force. A procedure of evaluating the generalized friction force in terms of the generalized coordinates and velocities is presented. A complete numerical algorithm for the entire intermittent interaction process is developed. The presence of dynamical stiffening is tested and the calculated values of the fundamental frequency are found in excellent agreement with data from literature. Simulation results for the time history of the normal contact force indicate that the contact zone is discontinuous, and that the force is strongly dependent on the hub angular speed and on the distance from the center to the flat surface.
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F. Paiva, Lucas, Hugo G. Lopes, Leonardo B. Felix i Rodolpho V. A. Neves. "Estimação do compasso musical do forró utilizando rede perceptron multicamadas". W Congresso Brasileiro de Automática - 2020. sbabra, 2020. http://dx.doi.org/10.48011/asba.v2i1.1331.
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Por meio da Lei No 13.409 de 2016, que altera a "Lei das Cotas" (Lei No 12.711 de 2012), tem-se a reserva de vagas para pessoas surdas no ensino superior, garantindo maior acesso desses estudantes à universidade. Ao mesmo tempo, há uma forte presenca do forró na cultura universitária. O forró é marcado por instrumentos de percussão, como o triângulo e a zabumba, e por compassos musicais que ditam a velocidade de movimento da dança. Visando a inclusãodo público surdo em atividades culturais envolvendo o forró, este trabalho propõe estimar o tempo de compasso musical em músicas de forró utilizando uma rede perceptron multicamadas (PMC). Um banco de dados com músicas de Forró Pé-de-serra e Universitário foi utilizado para treinamento da PMC. As saídas desejadas foram obtidas com o auxílio de uma instrutora de forró, que mediu o tempo de execução dos passos da dança para cada múusica. A estimaçãodo tempo de compasso realizada pela PMC atingiu precisão de 96% (erro méedio percentual aproximado de 4%), permitindo que pessoas surdas consigam sentir a música com erros médios de 65 ms. A aplicabilidade da abordagem será tratada em trabalhos futuros.
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Mishima, Akira, Yusuke Fuke, Atsuyuki Miura, Toshiki Hirogaki i Eiichi Aoyama. "Playing a Musical Saw With a Humanoid Robot: Investigation for Industrial Automation". W ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-97731.
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Abstract The objective of this study was to automate the dual-arm coordination of a humanoid robot when using a musical saw as a percussion instrument to produce a target sound. We examined the striking motion of the robot using its elastic stiffness, the change in vibration caused by the striking tool resulting from the robot arm-applied force on the saw, and dual arm cooperative motion based on striking sound feedback. To accomplish this, the frequency characteristics of the musical saw and the location of sound generation were determined. Based on the characteristics of the striking task and using an acoustic recognition system, we then developed an impact sound feedback system that could provide performance control of the two humanoid robot arms. The results indicate that humanoid robot can play the musical saw by controlling the curvature freely to achieve target sounds.
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Cherng, John G., Tong Ge i Sheng-Lih Peng. "Vibration Isolation and Damping for Bucking Bars". W ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/vib-4119.
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Abstract Bucking bars are used with pneumatic percussive rivet tools for airplanes, ships, and heavy vehicle constructions. The rivet is actually flattened by the bucking bar instead of the riveting hammer when the force is transmitted to the contact point between the rivet stem and the bucking bar. It has been proven that the operator who is holding the backing bar receives higher level of vibration than the person who is operating the rivet hammer. However, more attention has been given to the design modifications of the rivet hammer than the bucking bars which may due to the economic reasons. (The price of hammer is 50 to 100 times higher than the bucking bars’ price.) In this paper, the vibration characteristics of the bucking bars, the applications of vibration isolation and damping to the bucking bars, the optimum mass distribution calculated by a two degree-of-freedom model and the comparative results of the conventional bucking bar and ergonomically modified bucking bars are presented.
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Fu, Xinkang, Zhongwei Huang, Jinming Sun, Huaizhong Shi, Jiawei Zhang, Guodong Ji i Hengyu Song. "Numerical Simulation on Damage Characteristics of Carbonate Rock Under Axial-Torsional Coupled Impact by PDC Cutters". W 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0593.
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ABSTRACT Carbonate rock is an important oil and gas reservoir rock. Deep carbonate rocks are of high strength, hardness, abrasiveness and poor drillability, which will cause various problems as follows: PDC cutter collapse, serious wear and low drilling efficiency. Axial-torsional coupled percussive drilling can improve the drilling speed of deep hard rocks including carbonate rock. Therefore, a numerical model of axial-torsional coupled impact rock breakage was established for carbonate rocks. The damage characteristics of carbonate rock caused by spherical cutter and axe-shaped cutter under different impact parameters were analyzed. The simulation results reveal that the impact force of two kinds of cutters increases with the increase of impact speed. The torque of PDC cutters increases with the increase of torque amplitude. Under the same conditions, the tensile damage of carbonate rock caused by axe-shaped cutter is more obvious under the action of axial-torsional coupled impact and the tensile damage area under axe-shaped cutter tends to be connected. Additionally, the damage caused by PDC cutter to carbonate rocks is mainly tensile damage, supplemented by compressive damage. This work is instructive in revealing the effect of PDC cutter on breaking carbonate rocks under different impact parameters. INTRODUCTION As an important oil and gas reservoir rock, 50% of the world's proven oil and gas resources are stored in carbonate rocks (Al-Shargabi et al., 2022). Deep carbonate rocks are of high strength, hardness, abrasiveness and poor drillability. Conventional rotary bit drilling method has many problems in rock breaking, such as serious wear and low drilling efficiency (Jamali et al., 2019). Axial-torsional coupled percussive drilling has higher penetration rate in breaking hard rock, such as carbonate rock (Saai et al., 2020). And some oil companies designed some special-shaped PDC cutters (Zhu et al., 2022), such as axe-shaped cutter and spherical cutter. However, the characteristics of breaking carbonate rock by PDC cutters under the action of axial-torsional coupled impact is not clear. Therefore, it is of great significance to investigate the effect of different impact parameters on breaking carbonate rock by PDC cutters under the action of axial-torsional coupled impact.