37,014 research outputs found
Solidification/stabilisation of soil contaminated with metal: a review
Solidification/stabilisation (S/S) is generically defined as a chemical and physical alteration technique of reducing the mobility as well as solubility of contaminants in wastes in order to convert them into chemically inert form. The technique is specifically developed to confine the movement of contaminants in wastes so that their concentrations in the surrounding environment (e.g. subsurface soil matrices and groundwater) will not exceed stipulated environmental regulatory levels. This technique necessitates application of cementitious materials such as cement which also provides a favorable solidification effect on the stabilised wastes so that the end product can be easily transported to disposal sites or reused as construction materials. This paper reviews the S/S technology as applied to contaminated soil treatment with emphasis on its chemical binder systems, mechanisms, interferences and post-treatment leaching tests. S/S is an important soil contamination remediation technology as evident by its simplicity, technical and cost-effectiveness
Momentum Kick Model Description of the Ridge in (Delta-phi)-(Delta eta) Correlation in pp Collisions at 7 TeV
The near-side ridge structure in the (Delta phi)-(Delta eta) correlation
observed by the CMS Collaboration for pp collisions at 7 TeV at LHC can be
explained by the momentum kick model in which the ridge particles are medium
partons that suffer a collision with the jet and acquire a momentum kick along
the jet direction. Similar to the early medium parton momentum distribution
obtained in previous analysis for nucleus-nucleus collisions at 0.2 TeV, the
early medium parton momentum distribution in pp collisions at 7 TeV exhibits a
rapidity plateau as arising from particle production in a flux tube.Comment: Talk presented at Workshop on High-pT Probes of High-Density QCD at
the LHC, Palaiseau, May 30-June2, 201
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Provision of secondary frequency regulation by coordinated dispatch of industrial loads and thermal power plants
Demand responsive industrial loads with high thermal inertia have potential to provide ancillary service for frequency regulation in the power market. To capture the benefit, this study proposes a new hierarchical framework to coordinate the demand responsive industrial loads with thermal power plants in an industrial park for secondary frequency control. In the proposed framework, demand responsive loads and generating resources are coordinated for optimal dispatch in two-time scales: (1) the regulation reserve of the industrial park is optimally scheduled in a day-ahead manner. The stochastic regulation signal is replaced by the specific extremely trajectories. Furthermore, the extremely trajectories are achieved by the day-ahead predicted regulation mileage. The resulting benefit is to transform the stochastic reserve scheduling problem into a deterministic optimization; (2) a model predictive control strategy is proposed to dispatch the industry park in real time with an objective to maximize the revenue. The proposed technology is tested using a real-world industrial electrolysis power system based upon Pennsylvania, Jersey, and Maryland (PJM) power market. Various scenarios are simulated to study the performance of the proposed approach to enable industry parks to provide ancillary service into the power market. The simulation results indicate that an industrial park with a capacity of 500 MW can provide up to 40 MW ancillary service for participation in the secondary frequency regulation. The proposed strategy is demonstrated to be capable of maintaining the economic and secure operation of the industrial park while satisfying performance requirements from the real world regulation market
Humor at work that works: A multi-level examination of when and why leader humor promotes employee creativity
Although the role of leadership in fostering employee creativity has been extensively studied, it is still unclear whether and how leader humor affects employee creativity. Drawing upon cultural representation theory (CRT), we examined creative self-efficacy as a mediator and traditionality as a situational factor in the relationship between leader humor and employee creativity by analyzing a sample of 306 employees and 88 leaders (paired data) collected through survey questionnaire from firms based in Hubei Province, China, covering the industries of automobile, IT, and medicine. Following the multi-level examination, leader humor was positively related to employee creativity, and creative self-efficacy was found to mediate the impact of leader humor on employee creativity. Furthermore, traditionality moderated the effect of leader humor on creative self-efficacy, as well as the indirect effect of leader humor on employee creativity through creative self-efficacy. This study provides a social psychological explanation for the association between humor and employee creativity, deepens the current understanding of the influence process of leader humor. Finally, the theoretical and practical implications of the study are discussed at the end alongside limitations and recommendations for future research
FRW and domain walls in higher spin gravity
We present exact solutions to Vasiliev's bosonic higher spin gravity
equations in four dimensions with positive and negative cosmological constant
that admit an interpretation in terms of domain walls, quasi-instantons and
Friedman-Robertson-Walker (FRW) backgrounds. Their isometry algebras are
infinite dimensional higher-spin extensions of spacetime isometries generated
by six Killing vectors. The solutions presented are obtained by using a method
of holomorphic factorization in noncommutative twistor space and gauge
functions. In interpreting the solutions in terms of Fronsdal-type fields in
spacetime, a field-dependent higher spin transformation is required, which is
implemented at leading order. To this order, the scalar field solves
Klein-Gordon equation with conformal mass in (anti) de Sitter space. We
interpret the FRW solution with de Sitter asymptotics in the context of
inflationary cosmology and we expect that the domain wall and FRW solutions are
associated with spontaneously broken scaling symmetries in their holographic
description. We observe that the factorization method provides a convenient
framework for setting up a perturbation theory around the exact solutions, and
we propose that the nonlinear completion of particle excitations over FRW and
domain wall solutions requires black hole-like states.Comment: 63 page
Meson-Meson Scattering in Relativistic Constraint Dynamics
Dirac's relativistic constraint dynamics have been successfully applied to
obtain a covariant nonperturbative description of QED and QCD bound states. We
use this formalism to describe a microscopic theory of meson-meson scattering
as a relativistic generalization of the nonrelativistic quark-interchange model
developed by Barnes and Swanson.Comment: 5 pages, 1 figure in LaTex, talk present at the First Meeting of the
APS Topical Group on Hadronic Physics (Fermilab, October 24-26, 2004
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