590 research outputs found

    Jet Physics at the Tevatron

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    Jets have been used to verify the theory of quantum chromodynamics (QCD), measure the structure of the proton and to search for the physics beyond the Standard Model. In this article, we review the current status of jet physics at the Tevatron, a sqrt(s) = 1.96 TeV p-pbar collider at the Fermi National Accelerator Laboratory. We report on recent measurements of the inclusive jet production cross section and the results of searches for physics beyond the Standard Model using jets. Dijet production measurements are also reported.Comment: 29 pages, 12 figures, submitted to Ann.Rev.Nucl.Part.Sc

    HarvOS: Efficient code instrumentation for transiently-powered embedded sensing

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    We present code instrumentation strategies to allow transiently-powered embedded sensing devices efficiently checkpoint the system's state before energy is exhausted. Our solution, called HarvOS, operates at compile-time with limited developer intervention based on the control-flow graph of a program, while adapting to varying levels of remaining energy and possible program executions at run-time. In addition, the underlying design rationale allows the system to spare the energy-intensive probing of the energy buffer whenever possible. Compared to existing approaches, our evaluation indicates that HarvOS allows transiently-powered devices to complete a given workload with 68% fewer checkpoints, on average. Moreover, our performance in the number of required checkpoints rests only 19% far from that of an "oracle" that represents an ideal solution, yet unfeasible in practice, that knows exactly the last point in time when to checkpoint

    Barriers for the Adoption of Professional Development Courses (PDCs) in Public Sector University Libraries

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    Objective: The purpose of the study was to explore the major problems of Library Professionals working in the academic libraries of public sector universities regarding participation in Professional Development Courses (PDCs). Methodology: Public sector Universities affiliated with Higher Education Commission (HEC) Pakistan, located in Lahore, Pakistan were the target population. The Census sampling technique was adopted to accomplish the objectives of the conducted study. 67 respondents participated in the study. A quantitative research technique was used in the study. A self-created questionnaire was used to collect the data. Key Findings: The findings of the study revealed that a good number of respondents were willing to participate in development activities. But, due to numerous hurdles included shortage of library staff, poor allocation of budget for development activities and non-interesting attitude of organizational administration towards the professional development of Library professionals were the major barriers towards professional development activities. Rationale and Significance: Past literature indicated that no study was conducted covering the objective of barriers in professional development. No researcher made the proper investigation in the local scenario. It was highly desired to explore the barriers in participating in professional development activities in the local context. Implication: This study would contribute to the professional literature. It will also assist policy makers to take initiatives for the capacity building of library professionals

    Energy harvesting and wireless transfer in sensor network applications: Concepts and experiences

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    Advances in micro-electronics and miniaturized mechanical systems are redefining the scope and extent of the energy constraints found in battery-operated wireless sensor networks (WSNs). On one hand, ambient energy harvesting may prolong the systems lifetime or possibly enable perpetual operation. On the other hand, wireless energy transfer allows systems to decouple the energy sources from the sensing locations, enabling deployments previously unfeasible. As a result of applying these technologies to WSNs, the assumption of a finite energy budget is replaced with that of potentially infinite, yet intermittent, energy supply, profoundly impacting the design, implementation, and operation of WSNs. This article discusses these aspects by surveying paradigmatic examples of existing solutions in both fields and by reporting on real-world experiences found in the literature. The discussion is instrumental in providing a foundation for selecting the most appropriate energy harvesting or wireless transfer technology based on the application at hand. We conclude by outlining research directions originating from the fundamental change of perspective that energy harvesting and wireless transfer bring about

    Unsteady nonlinear magnetohydrodynamic micropolar transport phenomena with hall and ion-slip current effects : numerical study

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    Unsteady viscous two-dimensional magnetohydrodynamic micropolar flow, heat and mass transfer from an infinite vertical surface with Hall and Ion-slip currents is investigated theoretically and numerically. The simulation presented is motivated by electro-conductive polymer (ECP) materials processing in which multiple electromagnetic effects arise. The primitive boundary layer conservation equations are transformed into a non-similar system of coupled non-dimensional momentum, angular momentum, energy and concentration equations, with appropriate boundary conditions. The resulting two-point boundary value problem is solved numerically by an exceptionally stable and welltested implicit finite difference technique. A stability analysis is included for restrictions of the implicit finite difference method (FDM) employed. Validation with a Galerkin finite element method (FEM) technique is included. The influence of various parameters is presented graphically on primary and secondary shear stress, Nusselt number, Sherwood number and wall couple stress. Secondary (cross flow) shear stress is strongly enhanced with greater magnetic parameter (Hartmann number) and micropolar wall couple stress is also weakl y enhanced for small time values with Hartmann number. Increasing thermo-diffusive Soret number suppresses both Nusselt and Sherwood numbers whereas it elevates both primary and secondary shear stress and at larger time values also increases the couple stress. Secondary shear stress is strongly boosted with Hall parameter. Ion slip effect induces a weak modification in primary and secondary shear stress distributions. The present study is relevant to electroconductive non-Newtonian (magnetic polymer) materials processing systems

    Metachronal propulsion of a magnetized particle-fluid suspension in a ciliated channel with heat and mass transfer

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    Biologically inspired pumping systems are of great interest in modern engineering since they achieve enhanced efficiency and circumvent the need for moving parts and maintenance. Industrial applications also often feature two-phase flows. In this article, motivated by these applications, the pumping of an electrically conducting particle-fluid suspension due to metachronal wave propulsion of beating cilia in a two-dimensional channel with heat and mass transfer under a transverse magnetic field is investigated theoretically. The governing equations for mass and momentum conservation for fluid- and particle-phases are formulated by ignoring the inertial forces and invoking the long wavelength approximation. The Jeffrey viscoelastic model is employed to simulate non-Newtonian characteristics. The normalized resulting differential equations are solved analytically. Symbolic software is employed to evaluate the results and simulate the influence of different parameters on flow characteristics. Results are visualized graphically with carefully selected and viable data

    Ogbu and the debate on educational achievement: an exploration of the links between education, migration, identity and belonging

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    This paper looks at some of the issues raised by Ogbu’s work in relation to the education of different minority ethnic groups. Ogbu poses questions such as the value attached to education, its links to the future and its measurable outcomes in terms of ‘success’ as experienced by black participants. The desire for better life chances leads families to consider migration to a new country or resettlement within the same country, thus making migration both a local and a global phenomenon. As an example, attention is drawn to the situation facing South Asian children and their families in the UK. In terms of ethnicity and belonging, the wider question that is significant for many countries in the West after ‘Nine-Eleven’ is the education of Muslim children. A consideration of this current situation throws Ogbu’s identification of ‘autonomous minority’ into question. It is argued that a greater understanding of diverse needs has to be accompanied by a concerted effort to confront racism and intolerance in schools and in society, thus enabling all communities to make a useful contribution and to avoid the ‘risk’ of failure and disenchantment

    Mathematical modelling of nonlinear thermal radiation effects on EMHD peristaltic pumping of viscoelastic dusty fluid through a porous medium duct

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    Biologically-inspired propulsion systems are currently receiving significant interest in the aerospace sector. Since many spacecraft propulsion systems operate at high temperatures, thermal radiation is important as a mode of heat transfer. Motivated by these developments, in the present article, the influence of nonlinear thermal radiation (via the Rosseland diffusion flux model) has been studied on the laminar, incompressible, dissipative EMHD (Electro-magneto-hydrodynamic) peristaltic propulsive flow of a non-Newtonian (Jefferys viscoelastic) dusty fluid containing solid particles through a porous planar channel. The fluid is electrically-conducting and a constant static magnetic field is applied transverse to the flow direction (channel walls). Slip effects are also included. Magnetic induction effects are neglected. The mathematical formulation is based on continuity, momentum and energy equations with appropriate boundary conditions, which are simplified by neglecting the inertial forces and taking the long wavelength and lubrication approximations. The boundary value problem is then rendered non-dimensional with appropriate variables and the resulting system of reduced ordinary differential equations is solved analytically. The impact of various emerging parameters dictating the non-Newtonian propulsive flow i.e. Prandtl number, radiation parameter, Hartmann number, permeability parameter, Eckert number, particle volume fraction, electric field and slip parameter are depicted graphically. Increasing particle volume fraction is observed to suppress temperature magnitudes. Furthermore the computations demonstrate that an increase in particle volume fraction reduces the pumping rate in retrograde pumping region whereas it causes the opposite effect in the co-pumping region. The trapping mechanism is also visualized with the aid of streamline contour plots. Increasing thermal radiation elevates temperatures. Increasing Hartmann (magnetic body force) number decreases the size of the trapping bolus whereas the quantity of the does not effected. Conversely increasing particle volume fraction reduces the magnitude of the trapping bolus whereas the number of trapped bolus remains constant

    Assessment of multi-components and sectoral vulnerability to urban floods in Peshawar – Pakistan

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    Over the last two decades, urban floods and their impacts have been on the rise worldwide, owing to both climatic changes and human activities. The present study examines different at-risk elements, such as residential, commercial, and critical facilities, to evaluate their multi-components of vulnerability to urban floods in Peshawar, Pakistan. Based on the impacts of urban floods, the weightage of each component of the vulnerability for the selected elements at risk is defined. This study presents and uses the modified Fisher's ideal quantity index to combine the different vulnerability components into a single value. Additionally, the Patnaik and Narayan vulnerability index is employed to generalize sector-wise vulnerabilities across the study area. The results show that the old physical infrastructure of commercial and manufacturing units in the Kohati Gate area is highly vulnerable to urban floods, while the residential units are the least susceptible due to their distanced location from the drainage system. In Hayatabad, encroachments along the torrent's sides, affecting housing and educational institutions, contributed to increased vulnerability to urban floods, despite their relatively lower physical vulnerability. The study provides a new platform for understanding the multi-components of vulnerability to urban floods and tackling the challenges posed by urban floods effectively

    CMS Search Plans and Sensitivity to New Physics using Dijets

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    CMS will use dijets to search for physics beyond the standard model during early LHC running. The inclusive jet cross section as a function of jet transverse momentum, with 10 pb−1^{-1} of integrated luminosity, is sensitive to contact interactions beyond the reach of the Tevatron. The dijet mass distribution will be used to search for dijet resonances coming from new particles, for example an excited quark. Additional sensitivity to the existence of contact interactions or dijet resonances can be obtained by comparing dijet rates in two distinct pseudorapidity regions