541 research outputs found
Remote controlled partial discharge acquisition unit
Online partial discharge (PD) analysis for underground high voltage cables has major advantages over the offline techniques. Online techniques usually involve PD data acquisition, storage and post-processing of the data. However, the data acquisition process can be time consuming and troublesome because of design procedures and protocols required before commencement of data acquisition. This paper presents a robust remote controlled partial discharge acquisition unit for underground high voltage cable networks. This system is uniquely designed to incorporate the difficulties of accessibility, especially for remotely located substations. Real field data from a 33kV network is included in the paper
An evaluation of combined geophysical and geotechnical methods to characterize beach thickness
Beaches provide sediment stores and have an important role in the development of the coastline in response to climate change. Quantification of beach thickness and volume is required to assess coastal sediment transport budgets. Therefore, portable, rapid, non-invasive techniques are required to evaluate thickness where environmental sensitivities exclude invasive methods. Site methods and data are described for a toolbox of electrical, electromagnetic, seismic and mechanical based techniques that were evaluated at a coastal site at Easington, Yorkshire. Geophysical and geotechnical properties are shown to be dependent upon moisture content, porosity and lithology of the beach and the morphology of the beachâplatform interface. Thickness interpretation, using an inexpensive geographic information system to integrate data, allowed these controls and relationships to be understood. Guidelines for efficient site practices, based upon this case history including procedures and techniques, are presented using a systematic approach. Field results indicated that a mixed sand and gravel beach is highly variable and cannot be represented in models as a homogeneous layer of variable thickness overlying a bedrock half-space
Deformation-induced nanocrystallization - a comparison of two amorphous, Al-based, alloys
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83394/1/Jiang_JMR_2005.pd
Weakly-Interacting Bosons in a Trap within Approximate Second Quantization Approach
The theory of Bogoliubov is generalized for the case of a weakly-interacting
Bose-gas in harmonic trap. A set of nonlinear matrix equations is obtained to
make the diagonalization of Hamiltonian possible. Its perturbative solution is
used for the calculation of the energy and the condensate fraction of the model
system to show the applicability of the method.Comment: 6 pages, two figures .Presented at the International Symposium on
Quantum Fluids and Solids QFS2006 (Kyoto, Japan
An evaluation of combined geophysical and geotechnical methods to characterize beach thickness
Dynamical properties of liquid Al near melting. An orbital-free molecular dynamics study
The static and dynamic structure of liquid Al is studied using the orbital
free ab-initio molecular dynamics method. Two thermodynamic states along the
coexistence line are considered, namely T = 943 K and 1323 K for which X-ray
and neutron scattering data are available. A new kinetic energy functional,
which fulfills a number of physically relevant conditions is employed, along
with a local first principles pseudopotential. In addition to a comparison with
experiment, we also compare our ab-initio results with those obtained from
conventional molecular dynamics simulations using effective interionic pair
potentials derived from second order pseudopotential perturbation theory.Comment: 15 pages, 12 figures, 2 tables, submitted to PR
Professional closure by proxy: the impact of changing educational requirements on class mobility for a cohort of Big 8 partners
Closure events impacting on class mobility may include mechanisms initiated by bodies other than the professional body. The research examines if the introduction of full-time study requirements at universities for aspiring accountants effectively introduced a closure mechanism in the accounting profession. Data was derived from an Oral History study of partners in large firms. The younger partners (born after the Second World War) completed full-time degree study at university, but did not provide evidence of class mobility into the profession. The older cohort, born between 1928 and 1946, completed part-time studies only, few completed a degree, and, in contrast to the younger cohort, shows a perceptible upward movement from lower socio-economic classes into the professional class. This suggests that changing the preferred educational routes for new accountants entering the large chartered accounting (CA) firms compromised the "stepping stone" function of accounting as a portal into the professional class
Revised calibration of the mbt-cbt paleotemperature proxy based on branched tetraether membrane lipids in surface soils
The MBT-CBT proxy for the reconstruction of paleotemperatures and past soil pH is based on the distribution of branched glycerol dialkyl glycerol tetraether (brGDGT) membrane lipids. The Methylation of Branched Tetraether (MBT) and the Cyclisation of Branched Tetraether (CBT) indices were developed to quantify these distributions, and significant empirical relations between these indices and annual mean air temperature (MAT) and/or soil pH were found in a large data set of soils. In this study, we extended this soil dataset to 278 globally distributed surface soils. Of these soils, 26% contains all nine brGDGTs, while in 63% of the soils the seven most common brGDGTs were detected, and the latter were selected for calibration purposes. This resulted in new transfer functions for the reconstruction of pH based on the CBT index: pH = 7.90-1.97 x CBT (r(2) = 0.70; RMSE = 0.8; n = 176), as well as for MAT based on the CBT index and methylation index based on the seven most abundant GDGTs (defined as MBT'): MAT = 0.81-5.67 x CBT + 31.0 x MBT' (r(2) = 0.59; RMSE = 5.0 degrees C; n = 176). The new transfer function for MAT has a substantially lower correlation coefficient than the original equation (r(2) = 0.77). To investigate possible improvement of the correlation, we used our extended global surface soil dataset to statistically derive the indices that best describe the relations of brGDGT composition with MAT and soil pH. These new indices, however, resulted in only a relatively minor increase in correlation coefficients, while they cannot be explained straightforwardly by physiological mechanisms. The large scatter in the calibration cannot be fully explained by local factors or by seasonality, but MAT for soils from arid regions are generally substantially (up to 20 degrees C) underestimated, suggesting that absolute brGDGT-based temperature records for these areas should be interpreted with caution.<br>The applicability of the new MBT'-CBT calibration function was tested using previously published MBT-CBT-derived paleotemperature records covering the last deglaciation in Central Africa and East Asia, the Eocene-Oligocene boundary and the Paleocene-Eocene thermal maximum. The results show that trends remain similar in all records, but that absolute temperature estimates and the amplitude of temperature changes are lower for most records, and generally in better agreement with independent proxy data
Performance Issues in U.S.âChina Joint Ventures
Based on an in-depth study of U.S.-China joint ventures, this article offers some insights into the performance of such international business relationships. While the conventional literature treats government as an amorphous aspea of the political-legal environment, in this case government is an active participant and influence in the performance of international joint ventures (UVs). It has both a constraining and enabling effect on LJV structure, strategy, and performance. For example, limits can be placed on ownership shares of joint ventures and on prices of the output. At the same time, government can cooperate with LJVs and foreign parent companies by creating partners for foreign parent companies, acting as major customers, and improving financial performance by lowering taxes
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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