Academic literature on the topic 'Inverse integrating factor'
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Journal articles on the topic "Inverse integrating factor"
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Chavarriga, Javier, Hector Giacomini, Jaume Giné, and Jaume Llibre. "Darboux integrability and the inverse integrating factor." Journal of Differential Equations 194, no. 1 (October 2003): 116–39. http://dx.doi.org/10.1016/s0022-0396(03)00190-6.
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García, Isaac A., and Maite Grau. "A Survey on the Inverse Integrating Factor." Qualitative Theory of Dynamical Systems 9, no. 1-2 (July 30, 2010): 115–66. http://dx.doi.org/10.1007/s12346-010-0023-8.
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ALGABA, ANTONIO, CRISTÓBAL GARCÍA, and JAUME GINÉ. "Nilpotent centres via inverse integrating factors." European Journal of Applied Mathematics 27, no. 5 (March 23, 2016): 781–95. http://dx.doi.org/10.1017/s0956792516000103.
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In this paper, we are interested in the nilpotent centre problem of planar analytic monodromic vector fields. It is known that the formal integrability is not enough to characterize such centres. More general objects are considered as the formal inverse integrating factors. However, the existence of a formal inverse integrating factor is not sufficient to describe all the nilpotent centres. For the family studied in this paper, it is enough.
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García, Isaac A., Héctor Giacomini, and Maite Grau. "The inverse integrating factor and the Poincaré map." Transactions of the American Mathematical Society 362, no. 07 (February 17, 2010): 3591–612. http://dx.doi.org/10.1090/s0002-9947-10-05014-2.
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Llibre, Jaume, Chara Pantazi, and Sebastian Walcher. "Morphisms and inverse problems for Darboux integrating factors." Proceedings of the Royal Society of Edinburgh: Section A Mathematics 143, no. 6 (December 2013): 1291–302. http://dx.doi.org/10.1017/s0308210511001430.
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Polynomial vector fields which admit a prescribed Darboux integrating factor are quite well understood when the geometry of the underlying curve is non-degenerate. In the general setting, morphisms of the affine plane may remove degeneracies of the curve, and thus allow more structural insight. In the present paper we establish some properties of integrating factors subjected to morphisms, and we discuss in detail one particular class of morphisms related to finite reflection groups. The results indicate that degeneracies for the underlying curve generally impose additional restrictions on vector fields admitting a given integrating factor.
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李, 红伟. "Finding Integrating Factor or Inverse by Invariant Algebraic Curves." Pure Mathematics 10, no. 06 (2020): 593–98. http://dx.doi.org/10.12677/pm.2020.106072.
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Giacomini, Héctor, Jaume Giné, and Maite Grau. "Linearizable planar differential systems via the inverse integrating factor." Journal of Physics A: Mathematical and Theoretical 41, no. 13 (March 17, 2008): 135205. http://dx.doi.org/10.1088/1751-8113/41/13/135205.
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García, Isaac A. "Formal Inverse Integrating Factor and the Nilpotent Center Problem." International Journal of Bifurcation and Chaos 26, no. 01 (January 2016): 1650015. http://dx.doi.org/10.1142/s0218127416500152.
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We are interested in deepening the knowledge of methods based on formal power series applied to the nilpotent center problem of planar local analytic monodromic vector fields [Formula: see text]. As formal integrability is not enough to characterize such a center we use a more general object, namely, formal inverse integrating factors [Formula: see text] of [Formula: see text]. Although by the existence of [Formula: see text] it is not possible to describe all nilpotent centers strata, we simplify, improve and also extend previous results on the relationship between these concepts. We use in the performed analysis the so-called Andreev number [Formula: see text] with [Formula: see text] associated to [Formula: see text] which is invariant under orbital equivalency of [Formula: see text]. Besides the leading terms in the [Formula: see text]-quasihomogeneous expansions that [Formula: see text] can have, we also prove the following: (i) If [Formula: see text] is even and there exists [Formula: see text] then [Formula: see text] has a center; (ii) if [Formula: see text], the existence of [Formula: see text] characterizes all the centers; (iii) if there is a [Formula: see text] with minimum “vanishing multiplicity” at the singularity then, generically, [Formula: see text] has a center.
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Giné, Jaume. "The nondegenerate center problem and the inverse integrating factor." Bulletin des Sciences Mathématiques 130, no. 2 (March 2006): 152–61. http://dx.doi.org/10.1016/j.bulsci.2005.09.001.
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Algaba, Antonio, Natalia Fuentes, Cristóbal García, and Manuel Reyes. "Non-formally integrable centers admitting an algebraic inverse integrating factor." Discrete & Continuous Dynamical Systems - A 38, no. 3 (2018): 967–88. http://dx.doi.org/10.3934/dcds.2018041.
Full textDissertations / Theses on the topic "Inverse integrating factor"
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Ferragut, i. Amengual Antoni. "Polynomial inverse integrating factors of quadratic differential systems and other results." Doctoral thesis, Universitat Autònoma de Barcelona, 2006. http://hdl.handle.net/10803/3093.
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Aquesta tesi està dividida en dues parts diferents. En la primera, estudiam els sistemes quadràtics (sistemes polinomials de grau dos) que tenen un invers de factor integrant polinomial. En la segona, estudiam tres problemes diferents referits als sistemes diferencials polinomials. La primera part
En l'estudi dels sistemes diferencials plans el coneixement d'una integral primera és molt important. Els seus conjunts de nivell estan formats per òrbites i ens permeten dibuixar el retrat de fase del sistema, objectiu principal de la teoria qualitativa de les equacions diferencials al pla. Com ja se sap, existeix una bijecció entre l'estudi de les integrals primeres i l'estudi dels inversos de factor integrant. De fet, és més senzill l'estudi dels inversos de factor integrant que el de les integrals primeres. Una classe és dels sistemes quadràtics àmpliament estudiada dins els sistemes diferencials al pla és la dels sistemes quadràtics. Hi ha més d'un miler d'articles publicats sobre aquest tipus de sistemes, però encara som lluny de conèixer quins d'aquests sistemes són integrables, és a dir, si tenen una integral primera.
En aquest treball, estudiam els sistemes quadràtics que tenen un invers de factor integrant polinomial V = V(x, y), i per tant també tenen una integral primera, definida allà on no s'anul·la. Aquesta classe de sistemes diferencials és important per diferents motius:
1. La integral primera és sempre Darboux.
2. Conté la classe dels sistemes quàdratics homogenis, àmpliament estudiada (Date, Sibirskii, Vulpe...).
3. Conté la classe dels sistemes quàdratics amb un centre, també estudiada (Dulac, Kapteyn, Bautin,...).
4. Conté la classe dels sistemes quàdratics Hamiltonians (Artés, Llibre, Vulpe).
5. Conté la classe dels sistemes quàdratics amb una integral primera polinomial (Chavarriga, García, Llibre, Pérez de Rio, Rodríguez).
6. Conté la classe dels sistemes quàdratics amb una integral primera racional de grau dos (Cairó, Llibre).
La segona part
Presentam els següents tres articles:
1. A. Ferragut, J. Llibre and A. Mahdi, Polynomial inverse integrating factors for polynomial vector ?elds, to appear in Discrete and Continuous Dynamical Systems.
2. A. Ferragut, J. Llibre and M.A. Teixeira, Periodic orbits for a class of C(1) three-dimensional systems, submitted.
3. A. Ferragut, J. Llibre and M.A. Teixeira, Hyperbolic periodic orbits coming from the bifurcation of a 4-dimensional non-linear center, to appear in Int. J. Of Bifurcation and Chaos.
En el primer article donam tres resultats principals. Primer provam que un camp vectorial polinomial que té una integral primera polinomial té un invers de factor integrant polinomial. El segon resultat és un exemple d'un camp vectorial polinomial que té una integral primera racional i no té ni una integral primera polinomial ni un invers de factor integrant polinomial. Era un problema obert el fet de sebre si existien camps vectorials polinomials veri?cant aquestes condicions. El tercer resultat és un exemple d'un camp vectorial polinomial que té un centre i no té invers de factor integrant polinomial. Un exemple d'aquest tipus era esperat però desconegut en la literatura.
En el segon article estudiam camps vectorials polinomials reversibles de grau quatre en R(3) que tenen, sota certes condicions genèriques, un nombre arbitrari d'-orbitesperi-odiques hiperb-oliques. Sense aquestes condicions, tenen un nombre arbitrari d'òrbites periòdiques hiperbòliques. Sense aquestes condicions, tenen un nombre arbitrari d'òrbites periòdiques.
Finalment, en el tercer article, estudiam la pertorbació d'un centre de R(4) que prove d'un problema de la física. Mitjançant la teoria dels termes mitjans de primer ordre dins els camps vectorials polinomials de grau quatre, el sistema pertorbat pot tenir fins a setze òrbites periòdiques hiperbòliques bifurcant de les òrbites peròdiques del centre.
This thesis is divided into two different parts. In the first one, we study the quadratic systems (polynomial systems of degree two) having a polynomial inverse integrating factor. In the second one, we study three different problems related to polynomial differential systems.
The ?rst part.
It is very important, for planar differential systems, the knowledge of a ?rst integral. Its level sets are formed by orbits and they let us draw the phase portrait of the system, which is the main objective of the qualitative theory of planar differential equations.
As it is known, there is a bijection between the study of the ?rst integrals and the study of inverse integrating factors. In fact, it is easier to study the inverse integrating factors than the ?rst integrals.
A widely studied class of planar differential systems is the quadratic one. There are more than a thousand published articles about this subject of differential systems, but we are far away of knowing which quadratic systems are integrable, that is, if they have a ?rst integral.
In this work, we study the quadratic systems having a polynomial inverse integrating factor V = V (x, y), so they also have a ?rst integral, de?ned where V does not vanish. This class of quadratic systems is important for several reasons:
1. The ?rst integral is always Darboux.
2. It contains the class of homogeneous quadratic system, widely studied (Date, Sibirskii, Vulpe,...).
3. It contains the class of quadratic systems having a center, also studied (Dulac, Kapteyn, Bautin,...).
4. It contains the class of Hamiltonian quadratic systems (Artés, Llibre, Vulpe).
5. It contains the class of quadratic systems having a polynomial ?rst integral (Chavarriga, García, Llibre, Pérez de Rio, Rodríguez).
6. It contains the class of quadratic systems having a rational ?rst integral of de gree two (Cairó, Llibre).
The classi?cation of the quadratic systems having a polynomial inverse integrating factor is not completely ?nished. There remain near a 5% of the cases to study. We leave their study for an immediate future.
The second part.
We present the following three articles:
1. A. Ferragut, J. Llibre and A. Mahdi, Polynomial inverse integrating factors for polynomial vector ?elds, to appear in Discrete and Continuous Dynamical Systems.
2. A. Ferragut, J. Llibre and M.A. Teixeira, Periodic orbits for a class of C(1) three-dimensional systems, submitted.
3. A. Ferragut, J. Llibre and M.A. Teixeira, Hyperbolic periodic orbits coming from the bifurcation of a 4-dimensional non-linear center, to appear in Int. J. Of Bifurcation and Chaos.
In the first article we give three main results. First we prove that a polynomial vector field having a polynomial must have a polynomial inverse integrating factor. The second one is an example of a polynomial vector ?eld having a rational ?rst integral and having neither polynomial ?rst integral nor polynomial inverse integrating factor. It was an open problem to know if there exist polynomial vector ?elds verifying these conditions. The third one is an example of a polynomial vector ?eld having a center and not having a polynomial inverse integrating factor. An example of this type was expected but unknown in the literature.
In the second article we study reversible polynomial vector ?elds of degree four in R(3) which have, under certain generic conditions, an arbitrary number of hyperbolic periodic orbits. Without these conditions, they have an arbitrary number of periodic orbits.
Finally, in the third article, we study the perturbation of a center in R(4) which comes from a problem of physics. By the ?rst order averaging theory and perturbing inside the polynomial vector ?elds of degree four, the perturbed system may have at most sixteen hyperbolic periodic orbits bifurcating from the periodic orbits of the center.
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Kirsten, André Luís. "Reator eletrônico para lâmpadas de descarga em alta pressão baseado no conversor biflyback inversor." Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/8494.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe study of the best utilization of high intensity discharge lamps deals with the great global concern with energy efficiency. Electronic ballasts are the current devices that can make the good use of high luminous efficacy and the long useful life of these lamps. This work aims to develop an electronic ballast to supply high intensity discharge lamps. In order to avoid the acoustic resonance phenomenon occurrence, the lamp is supplied with low frequency square waveform. Power control and voltage inversion stage in the lamp are developed by the biflyback inverter topology. The analysis and design of this topology were performed, as well as the development of resonant inversion methodology of the lamp voltage. It is proposed one study, qualitative and quantitative, of active converters to provide the power factor correction, and their integration with the biflyback inverter topology. Buck biflyback inverter topology is chosen to the implementation of practical experiments, in order to validate the present work. The converter modeling, considering the lamp dynamic, such as the stability analysis and theoretical control strategy of current and lamp power are presented. Experimental results show that the proposed electronic ballast has the follow characteristics: high power factor (0.97), low input current harmonic distortion, high efficiency (88%) and not visible occurrence of acoustic resonance phenomenon.
O estudo do melhor aproveitamento das características das lâmpadas de descarga em alta pressão vem ao encontro da grande preocupação mundial com a eficientização energética. Reatores eletrônicos são os dispositivos atuais que melhor aproveitam a alta eficácia luminosa e longa vida útil dessas lâmpadas. Este trabalho visa o desenvolvimento de um reator eletrônico para a alimentação de lâmpadas de descarga em alta pressão. De modo a não excitar a ocorrência do fenômeno de ressonância acústica, a alimentação da lâmpada é realizada através de forma de onda de corrente quadrada em baixa frequência. Os estágios de controle de potência e inversão da tensão na lâmpada são realizados pela topologia biflyback inversora. A análise e projeto desta topologia foram realizados, assim como o desenvolvimento de uma metodologia de inversão ressonante da tensão da lâmpada. É proposto um estudo, qualitativo e quantitativo, dos conversores ativos para correção do fator de potência, e a integração destes, com a topologia biflyback inversora. A topologia buck biflyback inversora foi escolhida para a realização de experimentos práticos para a validação do trabalho. A modelagem do conversor, considerando a dinâmica de uma lâmpada de descarga em alta pressão de sódio foi realizada. Assim como a análise da estabilidade e estratégias de controle da corrente e da potência na lâmpada. Os resultados experimentais comprovam que o reator eletrônico proposto apresenta as características desejadas de: alto fator de potência (0,97), atendimento da norma IEC61000-3-2 para o nível das harmônicas da corrente de entrada, elevado rendimento (88%) e não excitação visível do fenômeno de ressonância acústica.
Book chapters on the topic "Inverse integrating factor"
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Algaba, Antonio, Natalia Fuentes, Cristóbal García, and Manuel Reyes. "Algebraic Inverse Integrating Factors for a Class of Generalized Nilpotent Systems." In SEMA SIMAI Springer Series, 287–300. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-32013-7_16.
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Décieux, Jean Philippe, and Elke Murdock. "Sense of Belonging: Predictors for Host Country Attachment Among Emigrants." In IMISCOE Research Series, 265–85. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67498-4_15.
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AbstractGerman citizens usually leave their home country voluntarily and face fewer barriers, e.g. in terms of freedom of travel or labour market integration. However, when arriving in their host country, they are confronted with the need to adapt to life in a new society. Analysing data from the German Emigration and Remigration Panel Study, we found that half of the emigrants developed a sense of belonging to their new host society. Moreover, we set out to examine this development of host country attachment. Guided by findings from acculturation and expatriate attachment research, we identified factors potentially contributing to host country attachment and tested these in a series of regression models. Permanence of the intended stay is the strongest predictor, and social integration also plays an important role. Host country language competence is also important for the identification processes. Regarding cultural distance, our findings suggest an inverted U-shaped relationship with certain cultural novelty facilitating the development of host country belonging. Moreover, the data point to a complex relationship between cultural characteristics of the target country and factors related to an emotional settlement.
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Amelung, Nina, Rafaela Granja, and Helena Machado. "Conclusion." In Modes of Bio-Bordering, 137–47. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-8183-0_9.
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Abstract The concluding chapter reviews and compares the modes of biobordering at the EU level and in Germany, the Netherlands, Poland, Portugal and the UK with a particular focus on the transnational exchange of DNA data within the Prüm system. This analysis reveals the multiplicity of heterogeneous biobordering regimes that enact different visions of Europe and nationhood and that have implications for de facto hidden integration and disintegration processes in the EU. ‘European integration’ is believed to be achievable by the harmonization of scientific and technical procedures in different countries. However, the mandatory elements of the Prüm Decisions were politically enforced without taking into consideration the significant differences between EU countries. Thus, hidden disintegration comes as a contingency regarding operational and organizational traditions, legislation, the nature of the criminal justice system, and national variations around the human and economic resources to invest in forensic DNA databases and DNA profiling technologies. The conclusion ends with a proposal of a typology systematizing biobordering dynamics derived from the empirical case studies.
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Freudlsperger, Christian. "More Voice, Less Exit." In Trade Policy in Multilevel Government, 12–50. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198856122.003.0002.
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The second chapter constructs a theoretical framework to account for the introduced research puzzle. Building on a central line of work on ‘federal dynamics’, it argues that the institutions and procedures of intergovernmental relations bear a decisive impact on a multilevel system’s ability to organize openness to international trade. While self-rule systems build on power-hoarding and the delineation of spheres of competence, shared rule systems rely on collaborative power-sharing between central and subcentral executives. In reference to Hirschman’s seminal concepts of exit and voice, the chapter then posits that any multilevel polity endows subcentral executives with a specific amount of voice in the making of trade and procurement policy. This voice it expects to be inversely related to exit: the more voice subcentral executives are equipped with, the less they dispose of an incentive to exit from a system-wide policy or international commitment. As shared-rule systems endow constituent units with more voice in polity-wide trade policy-making, they should organize openness more effectively than self-rule systems. At the same time, the inverse relationship between voice and exit does not unfold in an experimental vacuum. Depending on the specific policy sector, intervening factors can come to affect constituent units’ propensity to seek exit without affecting the amount of their voice. In the specific field of trade and procurement policy, the book expects two such policy-specific factors potentially to affect constituent units’ degree of exit. These are the amount of domestic procurement market integration and the politicization of international procurement liberalization.
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Mutohar, Agus, and Joan E. Hughes. "Toward Web 2.0 Integration in Indonesian Education." In Professional Development and Workplace Learning, 1867–84. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-8632-8.ch102.
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Numerous efforts have been made to reform education to address globalization both in developed and developing countries. The integration of technology in education has been one vital reform effort in developing countries to prepare graduates for 21st century workplaces, which are digitally robust. Web 2.0 technologies are becoming prominent educational and workplace tools. This literature review of Indonesian government policies, NGO initiative reports, and contemporary research explores the integration of Web 2.0 in Indonesian education using an ecological perspective by introducing the Indonesian national educational policy and laws, describing national and non-government organizations' initiatives focused on Web 2.0 integration, identifying salient national and local challenges preventing Web 2.0 integration, and proposing strategies for future planning and research. Challenges identified include lack of technological facilities, an absence of technology standards in education, a standardized testing culture, lack of coordination between government levels (national to local), lack of professional development, and a need for strong school technology leadership. The authors recommend Indonesia engage in comprehensive, visionary planning for Web 2.0 integration with strategies to meet local needs, invest in professional development and technology specialist positions, and advance mobile Web 2.0 computing and BYOT/D initiatives. Future research could examine how ecological factors at the national, provincial, and local levels coordinate to best establish Web 2.0 integration in education at the school level.
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Alpoim, Ângela, João Lopes, Tiago André Saraiva Guimarães, Carlos Filipe Portela, and Manuel Filipe Santos. "A Framework to Evaluate Big Data Fabric Tools." In Advances in Business Information Systems and Analytics, 180–91. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-5781-5.ch009.
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A huge growth in data and information needs has led organizations to search for the most appropriate data integration tools for different types of business. The management of a large dataset requires the exploitation of appropriate resources, new methods, as well as the possession of powerful technologies. That led the surge of numerous ideas, technologies, and tools offered by different suppliers. For this reason, it is important to understand the key factors that determine the need to invest in a big data project and then categorize these technologies to simplify the choice that best fits the context of their problem. The objective of this study is to create a model that will serve as a basis for evaluating the different alternatives and solutions capable of overcoming the major challenges of data integration. Finally, a brief analysis of three major data fabric solutions available on the market is also carried out, including Talend Data Fabric, IBM Infosphere, and Informatica Platform.
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Al-Busaidy, Moaman, and Vishanth Weerakkody. "E-Government Implementation in Oman." In E-Government Development and Diffusion, 272–80. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-713-3.ch015.
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With the advancement of the Internet and supporting information and communication technologies, e-government has emerged as an effective means of delivering government services to citizens. In the recent past, e-government has become popular in many developing countries. Most notably are the Middle Eastern countries that have continued to invest significantly into e-government initiatives in the last five years. The aim of this chapter is to examine e-government activities in the Sultanate of Oman and to identify factors that are currently impeding e-government development and implementation in this country. While issues such as lack of legal frameworks, strategy, project plans, usability issues and information quality are identified in the published literature as impeding e-government progress in Oman, this research suggests that factors such as web accessibility and integration of various government agencies also pose a major challenge for e-government implementation in Oman.
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Verhagen, Wim J. C., and Thijs Oudkerk. "Use of Textual Elements to Improve Reliability Prediction for Aircraft Component Behavior." In Advances in Transdisciplinary Engineering. IOS Press, 2020. http://dx.doi.org/10.3233/atde200116.
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Unplanned maintenance is a costly factor in aircraft operations. Predictive maintenance models aim to provide greater insight into future component and system behaviour. In the state of the art, a variety of statistical models and machine learning techniques, amongst others, are used to estimate component remaining useful life. These approaches commonly leverage technical information, such as sensor data. However, the use of data and techniques from other domains is not prevalent. One such example is the application of natural language processing to incorporate textual information, e.g. derived from pilot complaint data. In other words, does the presence and specific content of pilot complaints have potential to improve the predictability of component removals? In this research, data integration and processing from multiple disciplines are combined to address this question. Relevant words from pilot complaints are identified using a term frequency–inverse document frequency (TF-IDF) numerical analysis, after which the most relevant words are used as covariates in a proportional hazards model. Left truncation and right censoring is applied to limit the time-invariant nature of these covariates. The results in the form of hazard ratios indicate a hazard increase of several orders of magnitude with respect to baseline hazard, pointing towards potential value of including these words as predictive parameters.
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Dahan, Fadl, Khalil El Hindi, and Ahmed Ghoneim. "An Adapted Ant-Inspired Algorithm for Enhancing Web Service Composition." In Web Services, 904–21. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7501-6.ch049.
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Web Service Composition (WSC) provides a flexible framework for integrating independent web services to satisfy complex user requirements. WSC aims to choose the best web service from a set of candidates. The candidates have the same functionality and different non-functional criteria such as Quality of Service (QoS). In this work, the authors propose an ant-inspired algorithm for such problem. They named it Flying Ant Colony Optimization (FACO). Flying ants inject pheromone not only on the nodes on their paths but also on neighboring nodes increasing their chances of being explored in future iterations. The amount of pheromone deposited on these neighboring nodes is inversely proportional to the distance between them and the nodes on the path. The authors believe that by depositing pheromone on neighboring nodes, FACO may consider a more diverse population of solutions, which may avoid stagnation. The empirical experiments show that FACO outperform Ant Colony Optimization (ACO) for the WSC problem, in terms of the quality of solutions but it requires slightly more execution time.
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Broekaert, Wim, and Arjan Zuiderhoek. "Capital Goods in the Roman Economy." In Capital, Investment, and Innovation in the Roman World, 99–146. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198841845.003.0004.
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Research on the Roman economy and the possibility of Roman economic growth has focused on demographic structures, on market integration, on credit facilities, on technology and modes of organization, and on institutions and mentalities. A factor that has received less attention is investment in capital goods. Economists have found, however, that among all the different variables that might play a role in economic performance, investment in production equipment (tools, machinery) stimulates economic growth particularly strongly. This chapter focuses on three case studies: (1) agricultural tools, equipment, and workspaces; (2) capital goods used in riverine and maritime transport, i.e. ships and the tools and workspaces needed for shipbuilding; and (3) workspaces and tools employed in urban production and service provision. It asks who invested in these capital goods, who owned them, who produced them, and how production was organized. Most importantly, it investigates how capital goods were allocated among those who needed them, i.e. the people producing and transporting goods and services for consumption. It is concluded that, given the levels of wealth necessary to invest in the production of the types of capital goods discussed here, ownership of such capital goods would overwhelmingly have been concentrated in the hands of social and political elites, and it is argued that the social and legal ties that connected ordinary producers and distributors of consumption goods and services to these elites played a crucial role in determining the level of access they had to these capital goods.
Conference papers on the topic "Inverse integrating factor"
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GARCÍA, I. A., and D. S. SHAFER. "LIMIT SETS OF PLANAR VECTOR FIELDS AND THE VANISHING SET OF INVERSE INTEGRATING FACTORS." In Proceedings of the International Conference on Differential Equations. WORLD SCIENTIFIC, 2005. http://dx.doi.org/10.1142/9789812702067_0051.
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Derbanne, Quentin, Guillaume de Hauteclocque, and Martin Dumont. "How to Account for Short-Term and Long-Term Variability in the Prediction of the 100 Years Response?" In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61701.
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Current practices in offshore unit design are based on the prediction of the 100 years response (tension, offset, stress...). The methodologies described in various standards (ISO, API...) are all very similar: several design environments are described with a combination of sea state, wind and current. Usually envelope contours are used, describing a set of environmental conditions corresponding to a 100 years return period. These design conditions are supposed to produce the highest responses. A time domain (or sometimes frequency domain) simulation is done on each of these short-term conditions, and the 3h most probable maximum (MPM) is computed for each. The highest MPM over all the design conditions is taken as the 100 years response. This approach completely neglects the short-term variability of the response. This paper compares several design methods with the exact 100 years response. The exact 100 years response is computed by integrating the conditional short-term distributions with respect to the probability density function of the environmental conditions. The various design methods are all based on a simplification of an Inverse First Order Reliability Method (IFORM) approach, which requires computing one or several design conditions corresponding to one or several return periods, each of these conditions being associated with a given short-term quantile. Computations are done using two datasets. At first realistic line tensions of 7 offshore units are used, based on a large number of simulations with a mooring software. On a second stage a more general parametric model using a Weibull distribution to describe the long-term variability and a Gumbel distribution to describe the short-term distribution of the 3h maximum is used. It is shown that the current methods are unconservative with respect to the exact 100 years response. A more accurate method is proposed, based on a 40 years return period associated with the quantile 90% and a correction factor of 1.04.
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Salisbury, Shaun M., Matthew R. Jones, Brent W. Webb, and Vladimir P. Solovjov. "Sensitivity Analysis of an Inverse Method for Characterizing Industrial Foams." In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72720.
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Assessing the effect of a foam layer on critical transport phenomena is of significant interest in many industries, so a method for measuring structural and radiative properties of foam is being developed. A model of the propagation of radiation from an amplitude modulated laser beam through a non-absorbing foam layer has been developed using diffusion theory. Relationships between foam layer properties and measurable characteristics of the reflected radiative flux are obtained from this model. A parameter estimation method capable of inferring the targeted properties is being developed. As part of the development, a sensitivity study has been conducted to determine the optimal distance between the source and the detector. Factors influencing the accuracy of the estimated properties are identified, and a method to balance these competing factors is proposed. Simulated experimental measurements were generated using a Monte Carlo method, and the proposed method has been tested for a specific case. The reduced scattering coefficient and the thickness of a non-absorbing foam layer were determined to within 2% in this specific case.
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Wehage, R. A. "Solution of Multibody Dynamics Using Natural Factors and Iterative Refinement: Part I — Open Kinematic Loops." In ASME 1989 Design Technical Conferences. American Society of Mechanical Engineers, 1989. http://dx.doi.org/10.1115/detc1989-0115.
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Abstract An O(n) methodology employing block matrix partitioning and recursive projection to solve multibody equations of motion coupled by a sparse connectivity matrix was developed in (Wehage 1988, 1989, Wehage and Shabana, 1989). These primitive equations, which include all joint generalized and absolute coordinates and constraint reaction forces, are easily obtained from free body diagrams. The corresponding recursive algorithms isolate the generalized joint accelerations for numerical integration and offer the best computational advantage when solving long kinematic chains on serial processors. Recursion, however, precludes effective exploitation of vector or parallel processors. Therefore this paper explores less recursive algorithms by applying the inverse of joint connectivity to eliminate absolute accelerations and constraint forces yielding a generalized system of equations. The resulting positive definite generalized inertia matrix is first represented symbolically as a product of sparse matrices, of which some are singular and then as the product of nonsingular factors obtained recursively. This algorithm has overhead ranging from O(n2) to O(n) depending on the degree of system parallelism. Incorporating iterative refinement and exploiting parallel and vector processing makes this approach competitive for many applications.
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Quach, Nhi V., Quang N. Pham, Ju-Hwan Han, Youngjoon Suh, Jin-Seong Park, and Yoonjin Won. "Surface Engineering Through Atomic Layer Deposition on Three-Dimensionally Structured Materials." In ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipack2020-2613.
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Abstract Atomic layer deposition (ALD) is effective in depositing conformal thin films, which is highly favorable for coating various patterned surfaces. These coatings serve as barrier layers in addition to surface modifications to improve wettability of porous structures, such as meshes and membrane channels. However, it has been challenging to conformally deposit hydrophilic thin films on three-dimensionally (3D) designed, more complicated architectures. To understand the effect of surface modifications on 3D structures’ surface properties, we deposit thin silica films via ALD on hydrophobic porous media, which is nickel inverse opal structures in this case. The silica thin film is used to improve hydrophilicity without modifying the geometries of the microporous structure such as porosity, pore size, and metal type. We study the consequences of applying silica coatings to the 3D structure in comparison to flat surface counterpart. The hydrophilicity effects of ALD coating on porous structures and flat nickel surfaces are approximately the same with a result of decreasing apparent static contact angle of approximately 30°. In relation, the Fowkes method reveals the surface energy of the ALD silica samples increases by a factor of 1.3. Thermal stability of the coating is tested, revealing a relative degradation with increasing thermal cycling, most likely associated with the adsorption species on the thin film surface. The droplet spreading rate is analyzed in addition to droplet volume loss to estimate the liquid penetration rate into the structure, if any. Condensation rate and condensate growth show that despite having lower droplet nucleation in comparison to a flat surface, the droplet area growth on inverse opal regions is larger. These findings showcase potential improvements to 3D microporous structures by employing ALD coating for fluid transport through the porous media.
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Zhu, Xian-Kui. "Improved Elastic Compliance Equation and its Inverse Solution for Compact Tension Specimens." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65406.
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ASTM E1820 is a well-developed fracture test standard and has been used worldwide for fracture toughness testing on ductile materials in terms of the J-integral or J-R curve. This standard recommends the elastic unloading compliance technique for measuring crack length in a single specimen test, and an accurate elastic compliance equation is needed to estimate physical crack length. Compact tension (CT) specimen is one of the most often used standard specimens with crack length ratios of 0.45≤a/W≤0.70 prescribed in E1820 for J-R curve testing. The stress intensity factor K of CT specimens used in E1820 was developed by Srawley (IJF, 1976) and has been commonly accepted as the most accurate solution. The compliance equation of CT specimens was developed by Saxena and Hudak (IJF, 1978) and has been used in ASTM E1820 for decades. However, recent results showed that the load-line displacement (LLD) compliance equation is not consistent with that determined from its K solution, and the maximum error of LLD compliance can be larger than 7% at a/W = 0.32 and ∼ 5% at a/W = 0.45 (E1820 standard crack size). The FEA results confirmed that the K solution in E1820 is indeed very accurate, but its compliance equation is less accurate. Thus, an improved compliance equation with high accuracy is developed from the accurate K solution using the numerical integration technique and shooting method.
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Jung, Ki Wook, Sougata Hazra, Heungdong Kwon, Alisha Piazza, Edward Jih, Mehdi Asheghi, Man Prakash Gupta, Mike Degner, and Kenneth E. Goodson. "Parametric Study of Silicon-Based Embedded Microchannels With 3D Manifold Coolers (EMMC) for High Heat Flux (~1 kW/cm2) Power Electronics Cooling." In ASME 2019 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ipack2019-6472.
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Abstract Thermal management of power electronics continues to be one of the limiting factors in the peak power capability of the traction inverter system and overall efficiency of the e-drive. Successful design and implementation of Embedded Microchannels with a 3D-Manifold Cooler, or EMMC, could enable higher power density that allows increase in the inverter peak power output. In the present work, we have conducted a parametric study on geometric dimensions of the EMMCs to analyze thermofluidic performance by using computational fluid dynamics (CFD) simulations. The study was conducted for a 5 mm × 5 mm cold-plate foot print, heat flux 800 W/cm2, and single-phase water as working fluid at inlet temperature of 25 °C. We implemented strategies such as i) symmetric distribution of manifold inlet/outlet conduits, ii) reducing the thickness of cold-plate substrate, iii) increasing fluid-solid interfacial area in cold-plate microchannels that resulted in reduction in thermal resistance of the baseline EMMC design from 0.1 to 0.04 cm2-K/W with pressure drop from 8 to 37 kPa.
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Batura, Anatolii, Igor Orynyak, and Andrii Oryniak. "Semianalytical Method for the SIF Calculation for a Crack of Arbitrary Shape in Infinite Body." In ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28383.
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The exact analytical approach for stress intensity factor calculation for an arbitrary shape mode I crack loaded by the polynomial stresses is proposed. The approach is based on the calculation of the crack faces displacement at given loading. The displacement field is presented as a shape function multiplied by an adjustment polynomial. At that the key problem is the solution of well-known inverse task: obtaining the stresses field at the crack faces on the base of a given displacements field. Multiply solution of such task for a whole set of certain displacements base functions (e.g., for the single terms of the adjustment polynomial) allows to get analytical expression which connects stresses and displacements fields. The original semi-analytical technique for integration with subsequent differentiation of well-known singular integral equation of the flat crack problem is developed. The excellent accuracy of the method is confirmed for an elliptic crack as well as for a rectangular one in the infinite 3D body. New results are given for an inner semi-elliptic crack in the infinite body which surfaces are loaded by polynomial stresses up to the 6th order. The importance of choosing the appropriate shape function is demonstrated.
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Buono, Mario, Sonia Capece, and Francesca Cascone. "Industrial design for aircraft: models and usability for comfort in the cabin." In Systems & Design: Beyond Processes and Thinking. Valencia: Universitat Politècnica València, 2016. http://dx.doi.org/10.4995/ifdp.2016.3296.
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This contribution introduces an innovative model of assessment and validity of the formal-dimensional-functional structure for passenger seats in economy class in the Aerospace industry. In fact in this field, the design, ergonomics and engineering determine unpublished cooperation scenarios where roles are inverted, merge and recur repeatedly, in order to establish progress in the different planning and subject areas, having a synergistic and proactive perspective. The research activities have been developed within the framework of there search project “IMM_Interiors with Multifunctional Materials_DAC_Distretto Aerospaziale Campania” (Campania Aerospace District), in which experts from different branches of knowledge such as designers, innovative materials engineers, mechanical engineers, biologists and technical physicists from the Second University of Naples were involved. The use of new methodological dimensions resulted in the identification of common activity protocols, which were used as foundations in the planning stage, interdisciplinary and shared. The aim was to obtain a passenger seat configuration suitable to meet the demands and needs of the greatest number of individuals, according to their specifications and through the integration of innovative technologies and materials. The impact of different cultural factors, the mixture of roles and subjects, the layering of competences and heterogeneous and contradictory operational references have contributed towards a shared narrative where knowledge and experience have established the key principles in the course of evaluation and validity (methodological-designing inclusive). This route has allowed the acquisition of interdisciplinary skills and expertise qualified to obtain tangible results from the identification of methodological and design issues useful to optimize, innovate and streng then the design process. The goal was to make the acquisition of user needs systematic, through investigation and evaluation methods aimed at translating them into a structured format noted on the design process according to the principles of good design. In particular studies and research of prior art patents and thorough investigation literature regarding the state of the art of existing seat configurations and structures were carried out. Feasibility, comfort and reliability of the existing solutions in order to analyse and evaluate each component of ergonomics, human factors (physical ergonomics), user centred design and new human factors (pleasantness of use), where characteristics and specific meanings of quality, understood as a user-seat interaction quality are preferred.DOI: http://dx.doi.org/10.4995/IFDP.2016.3296
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Al-Qasim, Abdulaziz S., and Mohammed Alasker. "Asphaltenes: What Do We Know So Far." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-62366.
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Serious operational problems caused by asphaltene deposition during oil production have driven the ongoing effort to understand this phenomenon. Many studies have focused on related asphaltene precipitation flocculation and deposition in oil reservoirs and flow assurance in the wellbores. Experimental techniques and theoretical models have been developed trying to understand and predict asphaltene behavior. Nevertheless, some ambiguities still remain with regard to the characterization of asphaltene in crude oil and its stability during the primary, secondary, and tertiary recovery stages within the near-wellbore regions. The paper will review asphaltene in crude oil systems: asphaltene properties and their impact on oil production, including the effects of pressure, temperature, and composition. Asphaltene content is an important factor in determining the properties of a crude oil. Three main methods are used to measure the asphaltene content in laboratory: the first method called SARA, which separates dead oil into saturates, aromatics, resins, and asphaltenes depending on their solubility and polarity. The second is aliphatic hydrocarbon titration using dead oil; in this method the asphaltene precipitation point is detected by the asphaltene precipitation detection unit (APDU). The third method is the depressurization of a live oil bottomhole sample, this method depends on monitoring the flocculation point due to light transmittance caused by the infrared laser [3]. Solubility and density parameters trends are proportional to the pressure depletion until the pressure reaches the bubble point. Below the bubble point pressure (Pb), the solubility and density are inversely proportional to the pressure. The solubility increases linearly with temperature until the reservoir temperature, after that, it decreases linearly as the temperature increases. These advanced measurements facilitate an understanding of petroleum heavy constituents. Anew research field called “Petroleomics” has started receiving more attention; it is based on integrating the different knowledge of chemical composition of petroleum to develop correlation studies and improve the prediction of asphaltene phase behavior.