27,447 research outputs found
Compliance within a regulatory framework in implementing public road construction projects
© 2018 by the author(s). The construction industry faces a lack of compliance with policy that in Uganda public road construction projects affects the attainment of Government goals and disrupts infrastructure project delivery. For decades, public entities have been known for a lack of compliance that manifest in: poor performance, poor personnel management, poor resource utilization and unprofessionalism. In Uganda, this has resulted in several restructures aimed at improving service delivery. Despite this, compliance remains an issue. The purpose of this study is to establish factors affecting compliance within a public procurement regulatory framework in public road construction projects and foster economic development. A cross-sectional research design including a structured self-administered questionnaire survey and PLS-SEM data analysis by SmartPLS3 was conducted. The research reveals that three factors positively affect compliance with a regulatory framework that govern public road construction projects; sanctions on staff, inefficiency of the public procurement regulatory framework and contractors’ resistance to non-compliance. While a further three factors have little positive effect on compliance; familiarity, monitoring activities and professionalism. Hence, the research contributes to construction management by showing that sanctions, perceived inefficiency and contractors’ resistance significantly enhance compliance within a public procurement regulatory framework
The Euler-Lagrange Cohomology and General Volume-Preserving Systems
We briefly introduce the conception on Euler-Lagrange cohomology groups on a
symplectic manifold and systematically present the
general form of volume-preserving equations on the manifold from the
cohomological point of view. It is shown that for every volume-preserving flow
generated by these equations there is an important 2-form that plays the analog
role with the Hamiltonian in the Hamilton mechanics. In addition, the ordinary
canonical equations with Hamiltonian are included as a special case with
the 2-form . It is studied the other volume preserving
systems on . It is also explored the relations between
our approach and Feng-Shang's volume-preserving systems as well as the Nambu
mechanics.Comment: Plain LaTeX, use packages amssymb and amscd, 15 pages, no figure
Non-collinear magnetic structure and anisotropic magnetoelastic coupling in cobalt pyrovanadate Co2V2O7
The Co2V2O7 is recently reported to exhibit amazing magnetic field-induced
magnetization plateaus and ferroelectricity, but its magnetic ground state
remains ambiguous due to its structural complexity. Magnetometry measurements,
and time-of-flight neutron powder diffraction (NPD) have been employed to study
the structural and magnetic properties of Co2V2O7, which consists of two
non-equivalent Co sites. Upon cooling below the Ne\'el temperature TN = 6.3 K,
we observe magnetic Bragg peaks at 2K in NPD which indicated the formation of
long range magnetic order of Co2+ moments. After symmetry analysis and magnetic
structure refinement, we demonstrate that Co2V2O7 possesses a complicated
non-collinear magnetic ground state with Co moments mainly located in b-c plane
and forming a non-collinear spin-chain-like structure along the c-axis. The ab
initio calculations demonstrate that the non-collinear magnetic structure is
more stable than various ferromagnetic states at low temperature. The
non-collinear magnetic structure with canted up-up-down-down spin configuration
is considered as the origin of magnetoelectric coupling in Co2V2O7 because the
inequivalent exchange striction induced by the spin-exchange interaction
between the neighboring spins is the driving force of ferroelectricity.
Besides, it is found that the deviation of lattice parameters a and b is
opposite below TN, while the lattice parameter c and stay almost constant below
TN, evidencing the anisotropic magnetoelastic coupling in Co2V2O7.Comment: 9 pages, 8 figure
Gear shift schedule design for multi-speed pure electric vehicles
© IMechE 2014. As pure electric vehicles are considered to be a major growth trend in the automotive industry, research into and development of efficient electric powertrain systems and related control technologies have become popular research topics. The growing importance and use of multi-speed transmissions in these vehicles make shift schedule design and research a crucial aspect of the powertrain systems design of pure electric vehicles. This paper provides a gear shift schedule calculation method for pure electric vehicles, which includes a dynamic shift schedule and an economic shift schedule calculation method, demonstrating how to optimize the shift points and to produce the upshift and downshift lines based on the motor efficiency map. Through the establishment of a pure electric vehicle model, simulation results show that a properly designed shift schedule can improve the working region of the motor and can refine the dynamic performance and the economic performance of the vehicle. Finally, rig testing results are demonstrated to be comparable with simulations and indicate the correctness of the method
Specific Resistance of Pd/Ir Interfaces
From measurements of the current-perpendicular-to-plane (CPP) total specific
resistance (AR = area times resistance) of sputtered Pd/Ir multilayers, we
derive the interface specific resistance, 2AR(Pd/Ir) = 1.02 +/- 0.06 fOhmm^2,
for this metal pair with closely similar lattice parameters. Assuming a single
fcc crystal structure with the average lattice parameter, no-free-parameter
calculations, including only spd orbitals, give for perfect interfaces,
2AR(Pd/Ir)(Perf) = 1.21 +/-0.1 fOhmm^2, and for interfaces composed of two
monolayers of a random 50%-50% alloy, 2AR(Pd/Ir)(50/50) = 1.22 +/- 0.1 fOhmm^2.
Within mutual uncertainties, these values fall just outside the range of the
experimental value. Updating to add f-orbitals gives 2AR(Pd/Ir)(Perf) = 1.10
+/- 0.1 fOhmm^2 and 2AR(Pd/Ir)(50-50) = 1.13 +/- 0.1 fOhmm^2, values now
compatible with the experimental one. We also update, with f-orbitals,
calculations for other pairsComment: 3 pages, 1 figure, in press in Applied Physics Letter
The mechanical relaxation study of polycrystalline MgCNi3
The mechanical relaxation spectra of a superconducting and a
non-superconducting MgCNi3 samples were measured from liquid nitrogen
temperature to room temperature at frequency of kilohertz. There are two
internal friction peaks (at 300 K labeled as P1 and 125 K as P2) for the
superconducting sample. For the non-superconducting one, the position of P1
shifts to 250 K, while P2 is almost completely depressed. It is found that the
peak position of P2 shifts towards higher temperature under higher measuring
frequency. The calculated activation energy is 0.13eV. We propose an
explanation relating P2 to the carbon atom jumping among the off-center
positions. And further we expect that the behaviors of carbon atoms maybe
correspond to the normal state crossovers around 150 K and 50 K observed by
many other experiments.Comment: 4 figure
Search for via the transition at LHCb and factory
It is interesting to study the characteristics of the whole family of
which contains two different heavy flavors. LHC and the proposed factory
provide an opportunity because a large database on the family will be
achieved. and its excited states can be identified via their decay modes.
As suggested by experimentalists, is not easy to be
clearly measured, instead, the trajectories of and occurring in
the decay of () can be unambiguously
identified, thus the measurement seems easier and more reliable, therefore this
mode is more favorable at early running stage of LHCb and the proposed
factory. In this work, we calculate the rate of
in terms of the QCD multipole-expansion and the numerical results indicate that
the experimental measurements with the luminosity of LHC and factory are
feasible.Comment: 12 pages, 1 figures and 4 tables, acceptted by SCIENCE CHINA Physics,
Mechanics & Astronomy (Science in China Series G
Validity of the Generalized Second Law of Thermodynamics of the Universe Bounded by the Event Horizon in Brane Scenario
In this paper, we examine the validity of the generalized second law of
thermodynamics (GSLT) of the universe bounded by the event horizon in
brane-world gravity. Here we consider homogeneous and isotropic model of the
universe filled with perfect fluid in one case and in another case holographic
dark energy model of the universe has been considered. The conclusions are
presented point wise.Comment: 8 pages, the paper has been accepted in EPJC for publication.
Conclusion has been modified an some references have been adde
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