Documents disponibles écrits par cet auteur

Analysing the impact of the implementation of lean manufacturing strategies on profitability / D. J. Meade in Journal of the operational research society (JORS), Vol. 61 N° 5 (Mai 2010) 

Public ISBD [article]  in Journal of the operational research society (JORS) > Vol. 61 N° 5 (Mai 2010) . - pp. 858–871 Titre : Analysing the impact of the implementation of lean manufacturing strategies on profitability Type de document : texte imprimé Auteurs : D. J. Meade, Auteur ; Kumar, S., Auteur ; B. White, Auteur Année de publication : 2010 Article en page(s) : pp. 858–871 Note générale : Recherche Opérationnelle Langues : Anglais (eng) Mots-clés : Accounting  Cost  allocation  Inventory  Lean  manufacturing  Simulation  Stochastic  processes Index. décimale : 001.424 Résumé : Under standard cost accounting systems, reductions in inventories lead to falling reported profits. Rapid reductions in inventories intensify the impact to the bottom line. When a company embarks on an improvement programme such as lean manufacturing, a likely result will be an initial drop in reported profits due to the leaning out of inventories. This paper examines the impact of the adoption of such strategies on the key external financial performance measure of net profit as reported by the GAAP and SEC approved financial accounting methods and others. ANOVA analysis of data generated using a simulated manufacturing environment that includes a discrete event model of a manufacturing operation and a Microsoft Excel-based ERP system are discussed. The paper analyses both the magnitude of the reduction in reported profits and the span of reporting periods affected under three inventory reduction scenarios. This research was not concerned with finding justification for lean manufacturing strategies. Rather, it evaluates the inadequacies of standard financial reporting methods to accurately reflect operational improvements through the early stages of a lean programme. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n5/abs/2602657a.html [article] Analysing the impact of the implementation of lean manufacturing strategies on profitability [texte imprimé] / D. J. Meade, Auteur ; Kumar, S., Auteur ; B. White, Auteur . - 2010 . - pp. 858–871. Recherche Opérationnelle Langues : Anglais (eng) in Journal of the operational research society (JORS) > Vol. 61 N° 5 (Mai 2010) . - pp. 858–871 Mots-clés : Accounting  Cost  allocation  Inventory  Lean  manufacturing  Simulation  Stochastic  processes Index. décimale : 001.424 Résumé : Under standard cost accounting systems, reductions in inventories lead to falling reported profits. Rapid reductions in inventories intensify the impact to the bottom line. When a company embarks on an improvement programme such as lean manufacturing, a likely result will be an initial drop in reported profits due to the leaning out of inventories. This paper examines the impact of the adoption of such strategies on the key external financial performance measure of net profit as reported by the GAAP and SEC approved financial accounting methods and others. ANOVA analysis of data generated using a simulated manufacturing environment that includes a discrete event model of a manufacturing operation and a Microsoft Excel-based ERP system are discussed. The paper analyses both the magnitude of the reduction in reported profits and the span of reporting periods affected under three inventory reduction scenarios. This research was not concerned with finding justification for lean manufacturing strategies. Rather, it evaluates the inadequacies of standard financial reporting methods to accurately reflect operational improvements through the early stages of a lean programme. DEWEY : 001.424 ISSN : 0361-5682 En ligne : http://www.palgrave-journals.com/jors/journal/v61/n5/abs/2602657a.html

Flow past a rotating cylinder at low and high rotation rates / Kumar, S. in Transactions of the ASME . Journal of fluids engineering, Vol. 133 N° 4 (Avril 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 133 N° 4 (Avril 2011) . - 09 p. Titre : Flow past a rotating cylinder at low and high rotation rates Type de document : texte imprimé Auteurs : Kumar, S., Auteur ; Cantu, C., Auteur ; Gonzalez, B., Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Fluids engineering Langues : Anglais (eng) Mots-clés : Bubbles  External  flows  Flow  visualisation  Laminar  flow  Pattern  formation  Vortices  Wakes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Flow past a rotating circular cylinder is studied experimentally. The experiments are carried out in a water tunnel at Reynolds numbers of 200, 300, and 400 and nondimensional rotation rates (ratio of surface speed of the cylinder to the free stream velocity), alpha, varying from 0 to 5. The diagnostic is done by flow visualization using hydrogen bubble technique and quantitative measurements using a particle image velocimetry technique. We present the global view of the wake structure at the three Reynolds numbers and various rotation rates. Vortex shedding activity is observed to occur from alpha=0 to alpha~1.95, after which it is suppressed. Reynolds number is found to have a strong effect on the wake morphology near the suppression rotation rate, alpha=1.95. Interestingly, the vortex shedding activity again resumes in the range 4.34 DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA400013 [...] [article] Flow past a rotating cylinder at low and high rotation rates [texte imprimé] / Kumar, S., Auteur ; Cantu, C., Auteur ; Gonzalez, B., Auteur . - 2011 . - 09 p. Fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 133 N° 4 (Avril 2011) . - 09 p. Mots-clés : Bubbles  External  flows  Flow  visualisation  Laminar  flow  Pattern  formation  Vortices  Wakes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Flow past a rotating circular cylinder is studied experimentally. The experiments are carried out in a water tunnel at Reynolds numbers of 200, 300, and 400 and nondimensional rotation rates (ratio of surface speed of the cylinder to the free stream velocity), alpha, varying from 0 to 5. The diagnostic is done by flow visualization using hydrogen bubble technique and quantitative measurements using a particle image velocimetry technique. We present the global view of the wake structure at the three Reynolds numbers and various rotation rates. Vortex shedding activity is observed to occur from alpha=0 to alpha~1.95, after which it is suppressed. Reynolds number is found to have a strong effect on the wake morphology near the suppression rotation rate, alpha=1.95. Interestingly, the vortex shedding activity again resumes in the range 4.34 DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA400013 [...]

Pressure, flow, force, and torque between the barrel and port plate in an axial piston pump / J. M. Bergada in Transactions of the ASME . Journal of dynamic systems, measurement, and control, Vol. 130 N°1 (Janvier/Fevrier 2008) 

Public ISBD [article]  in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N°1 (Janvier/Fevrier 2008) . - 16 p. Titre : Pressure, flow, force, and torque between the barrel and port plate in an axial piston pump Type de document : texte imprimé Auteurs : J. M. Bergada, Auteur ; J. Watton, Auteur ; Kumar, S., Auteur Année de publication : 2008 Article en page(s) : 16 p. Note générale : dynamic systems Langues : Anglais (eng) Mots-clés : barrel;  axial  piston  pump;  pressure  distribution;  leakage;  force;  torque Résumé : This paper analyzes the pressure distribution, leakage, force, and torque between the barrel and the port plate of an axial piston pump. A detailed set of new equations is developed, which takes into account important parameters such as tilt, clearance and rotational speed, and timing groove. The pressure distribution is derived for different operating conditions, together with a complementary numerical analysis of the original differential equations, specifically written for this application and used to validate the theoretical solutions. An excellent agreement between the two approaches is shown, allowing an explicit analytical insight into barrel/port plate operating characteristics, including consideration of cavitation. The overall mean force and torques over the barrel are evaluated and show that the torque over the XX axis is much smaller than the torque over the YY axis, as deduced from other nonexplicit simulation approaches. A detailed dynamic analysis is then studied, and it is shown that the torque fluctuation over the YY axis is typically 8% of the torque total magnitude. Of particular novelty is the prediction of a double peak in each torque fluctuation resulting from the more exact modeling of the piston/port plate/timing groove pressure distribution characteristic during motion. A comparison between the temporal torque fluctuation pattern and another work shows a good qualitative agreement. Experimental and analytical results for the present study demonstrate that barrel dynamics do contain a component primarily directed by the torque dynamics. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...] [article] Pressure, flow, force, and torque between the barrel and port plate in an axial piston pump [texte imprimé] / J. M. Bergada, Auteur ; J. Watton, Auteur ; Kumar, S., Auteur . - 2008 . - 16 p. dynamic systems Langues : Anglais (eng) in Transactions of the ASME . Journal of dynamic systems, measurement, and control > Vol. 130 N°1 (Janvier/Fevrier 2008) . - 16 p. Mots-clés : barrel;  axial  piston  pump;  pressure  distribution;  leakage;  force;  torque Résumé : This paper analyzes the pressure distribution, leakage, force, and torque between the barrel and the port plate of an axial piston pump. A detailed set of new equations is developed, which takes into account important parameters such as tilt, clearance and rotational speed, and timing groove. The pressure distribution is derived for different operating conditions, together with a complementary numerical analysis of the original differential equations, specifically written for this application and used to validate the theoretical solutions. An excellent agreement between the two approaches is shown, allowing an explicit analytical insight into barrel/port plate operating characteristics, including consideration of cavitation. The overall mean force and torques over the barrel are evaluated and show that the torque over the XX axis is much smaller than the torque over the YY axis, as deduced from other nonexplicit simulation approaches. A detailed dynamic analysis is then studied, and it is shown that the torque fluctuation over the YY axis is typically 8% of the torque total magnitude. Of particular novelty is the prediction of a double peak in each torque fluctuation resulting from the more exact modeling of the piston/port plate/timing groove pressure distribution characteristic during motion. A comparison between the temporal torque fluctuation pattern and another work shows a good qualitative agreement. Experimental and analytical results for the present study demonstrate that barrel dynamics do contain a component primarily directed by the torque dynamics. En ligne : http://dynamicsystems.asmedigitalcollection.asme.org/issue.aspx?journalid=117&is [...]