308 research outputs found

    Simulation aided development of pre-chamber ignition system for a lean-burn gasoline direct injection motor-sport engine

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    Due to recent regulation changes to restricted fuel usage in various motor-sport events, motor-sport engine manufacturers have started to focus on improving the thermal efficiency and often claim thermal efficiency figures well above equivalent road car engines. With limited fuel allowance, motorsport engines are operated with a lean air-fuel mixture to benefit from higher cycle efficiency, requiring an ignition system that is suitable for the lean mixture. Pre-chamber ignition is identified as a promising method to improve lean limit and has the potential to reduce end gas auto-ignition. This paper analyses the full-load performance of a motor-sport lean-burn GDI engine and a passive pre-chamber is developed with the aid of a CFD tool. The finalized pre-chamber design benefited in a significant reduction in burn duration, reduced cyclic variation, knock limit extension and higher performance

    Influence of Different Abutment Designs on the Biomechanical Behavior of One-Piece Zirconia Dental Implants and Their Surrounding Bone: A 3D-FEA

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    Background: In a dental implant/bone system, the design factors affect the value and distributions of stress and deformations that plays a pivotal role on the stability, durability and lifespan of the implant/bone system

    Community-Based Responsible Leadership and Social Value Creation in Social Enterprise Context

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    This chapter proposes a model of community-based responsible leadership which focuses on moral identification at individual and team levels within the context of social entrepreneurship. In this proposal, we first discuss the organizing principles of a community and the relevance of studying responsible leadership within the context of social entrepreneurship. Then the contributions of this chapter are outlined. Integrating theories of social identity model of leadership, collective action, and moral identity, a multi-level model of collective responsible leadership that results in social value creation is conceptualized

    Myofilament Phosphorylation and Function in Diastolic Heart Failure

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    The Role of Research Universities in Catalyzing Value Creation

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    Through this chapter we focus on the impact of research universities’ publicly funded research projects on the economy in terms of knowledge creation, knowledge transfer, and business ethics promotion. We aim to answer the research question of how universities and science can provide tools that have a positive effect on the economy, including small and medium enterprises (SMEs). This chapter sheds light on how universities provide tools, evidence, and new knowledge that catalyze value creation. With the illustrations of two university contexts, one in the US and the other in Hong Kong, we offer insights on how scientific research projects do not only serve the sole purpose of publication. Scientific research projects serve to connect the academic and practice fields in knowledge creation and exchange; to create an experiential learning ground for students; and to provide examination and curation of market trends for sectoral growth. Through the first part of the book chapter, we present past research on the impact of universities on the economy, SMEs, and their communities. The second part of the chapter explains the data curation efforts led at the Institute for Research on Innovation and Science (IRIS), which is a consortium of US research universities adopting large administrative data, to investigate and provide the evidence of the effect of higher education universities on the economy, SMEs, the career pathways of students, and on national prosperity. We examine cases in which federally funded projects have led to a positive impact on the economy, including SMEs. The third part of the chapter examines the engagement of business school students in the examination of entrepreneurial ethics in a research university in Hong Kong, a rising economy. Students were engaged in an active knowledge creation process. The experience of students’ research contribution to a business ethics index which was published annually for ten years is discussed. Students at a business school who collected data for a Junzi Corporation Survey every year in Hong Kong embarked on a learning journey that stimulated their business ethics learning. The outcomes of the research serve to inform the business sectors in terms of the values that shape responsible management towards the important customer stakeholder group

    Protein phosphatase 5 regulates titin phosphorylation and function at a sarcomere-associated mechanosensor complex in cardiomyocytes.

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    Serine/threonine protein phosphatase 5 (PP5) is ubiquitously expressed in eukaryotic cells; however, its function in cardiomyocytes is unknown. Under basal conditions, PP5 is autoinhibited, but enzymatic activity rises upon binding of specific factors, such as the chaperone Hsp90. Here we show that PP5 binds and dephosphorylates the elastic N2B-unique sequence (N2Bus) of titin in cardiomyocytes. Using various binding and phosphorylation tests, cell-culture manipulation, and transgenic mouse hearts, we demonstrate that PP5 associates with N2Bus in vitro and in sarcomeres and is antagonistic to several protein kinases, which phosphorylate N2Bus and lower titin-based passive tension. PP5 is pathologically elevated and likely contributes to hypo-phosphorylation of N2Bus in failing human hearts. Furthermore, Hsp90-activated PP5 interacts with components of a sarcomeric, N2Bus-associated, mechanosensor complex, and blocks mitogen-activated protein-kinase signaling in this complex. Our work establishes PP5 as a compartmentalized, well-controlled phosphatase in cardiomyocytes, which regulates titin properties and kinase signaling at the myofilaments

    Assessing indicators of runoff and erosion by rain simulation in the Ben Ahmed watershed (Central Morocco)

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    The objective of this study was to investigate the risks of runoff and erosion of soils in the Ben Ahmed watershed, it's located in the region of casa-settat, 70 km south-east of Casablanca, and characterized by a semi-arid climate. The study consists of measuring on 1 m2 plot, the volumes of runoff and sediments, under the influence of rainfall generation (60mm/30 min). Soil samples were collected from each plot to determine texture, organic matter and humidity. Results obtained show that the detachability varies between 19 and 34 g/l, infiltrability oscillate between 15 and 37 mm.h-. Pearson correlation test shows that infiltration was negatively correlated with runoff and soil detachability (R=-0.99, R=-0.87 respectively). It‘s significantly correlated with the proportions of sand(R=0.69), silt (R= -0.98) an clay (R= 0.92), however, is weakly correlated with organic matter (R=-0.32). Infiltration and detachability were significantly correlated with humidity (R = -0.99, R = -0.63respectively)

    Ecodialysis: is it possible an eco-friendly system?

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    In medicine, attention to the environmental impact is still limited. Most of the analyses so far performed regard the last part of the cycle, the "grave of waste products". Chronic Hemodialysis produces about 600,000 tons of plastic waste per year. The economic crisis and the awareness of damage to the ecosystem progressively induced to focus attention on the lifespan of disposable, "from cradle to grave". A new outlook is presently focussed on recycle, that is the subsequent start of new cycles leading to a "from cradle to cradle" model: allowing a "new life" for the waste products, despite the need for initial investment. Aim of the present study is an analysis of the characteristics of the disposables employed in chronic hemodialysis, as a tool for identifying strategies limiting the environmental impact and containing the costs

    Study of State Estimation Using Weighted Least Squares Method

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    Power state estimation constitutes the core of the on-line security analysis function. The challenge number one of a state estimator is to provide the optimal estimates of system state with minimum of measurement data. This paper describes weighted least squares state estimation method and investigates how the efficiency of WLS state estimation changes according to 4 parameters: number of measurements, measurement type, measurement weight and level of noise. Different simulation cases are tested on 3-bus system and IEEE 14-bus system. The results show that accurate estimates of system state can be obtained with minimum of measurement data on condition to choose a good combination of accurate measurements with a minimum of voltage measurements and power injection measurements and these data should be properly distributed throughout the system. For best results, the two factors (weight and noise) must be combined to obtain the best estimation. Indeed, the most accurate measurements (lower level of noise) should have greater weight compared to bad measurements (higher level of noise), specially voltage measurements due to their big impact
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