Mixed quantum-classical dynamics from the exact decomposition of electron-nuclear motion

We present a novel mixed quantum-classical approach to the coupled electron-nuclear dynamics based on the exact factorization of the electron-nuclear wave function, recently proposed in [A. Abedi, N. T. Maitra, and E. K. U. Gross, Phys. Rev. Lett. 105, 123002 (2010)]. In this framework, classical nuclear dynamics is derived as the lowest order approximation of the time dependent Schr\"odinger equation that describes the evolution of the nuclei. The effect of the time dependent scalar and vector potentials, representing the exact electronic back-reaction on the nuclear subsystem, is consistently derived within the classical approximation. We examine with an example the performance of the proposed mixed quantum-classical scheme in comparison with exact calculations

Laser-induced electron localization in H2+_2^+: Mixed quantum-classical dynamics based on the exact time-dependent potential energy surface

We study the exact nuclear time-dependent potential energy surface (TDPES) for laser-induced electron localization with a view to eventually developing a mixed quantum-classical dynamics method for strong-field processes. The TDPES is defined within the framework of the exact factorization [A. Abedi, N. T. Maitra, and E. K. U. Gross, Phys. Rev. Lett. 105, 123002 (2010)] and contains the exact effect of the couplings to the electronic subsystem and to any external fields within a scalar potential. We compare its features with those of the quasistatic potential energy surfaces (QSPES) often used to analyse strong-field processes. We show that the gauge-independent component of the TDPES has a mean-field-like character very close to the density-weighted average of the QSPESs. Oscillations in this component are smoothened out by the gauge-dependent component, and both components are needed to yield the correct force on the nuclei. Once the localization begins to set in, the gradient of the exact TDPES tracks one QSPES and then switches to the other, similar to the description provided by surface-hopping between QSPESs. We show that evolving an ensemble of classical nuclear trajectories on the exact TDPES accurately reproduces the exact dynamics. This study suggests that the mixed quantum-classical dynamics scheme based on evolving multiple classical nuclear trajectories on the exact TDPES will be a novel and useful method to simulate strong field processes.Comment: 10 pages, 6 figure

Performance of Wick Drains in Boston Blue Clay

The use of wick drains to accelerate the consolidation of soft clays is a cost effective alternative to the use of pile foundations. This paper presents a case history of using wick drains to accelerate the consolidation of a 5. 7 acre area in Metropolitan Boston, Massachusetts, USA. Boston Blue Clay was encountered approximately 25 to 40 ft below existing grade with varied thickness and consistency. Wick drains were installed to a depth of 70 ft in a triangular pattern. Geotechnical instruments were installed to monitor the settlement of clay with time. As a result of the preconsolidation program, about $8 million was saved in construction cost

The Effect of Hidden Quality Cost on Supply Chain Management of Sales and Market Share

There have been difficulties in managing costs effectively which have led to reduction in both market and sales share. This study aimed to find remedies to the challenge of determining and measuring the hidden quality costs due to its negative effect on the customer satisfaction. This study engaged in the measurement and calculation of hidden quality costs in a sound and scientific manner in order to find solutions to the problem and achieve the research objectives. Increase in the sales and profits and market share of the economic unit and satisfaction of the customer are achieved through the effective the management of these costs. A deductive approach was employed in the study and a number of conclusions were made from the analysis of the results. First, the study conclude that lack of information as provided by the total quality costs is experienced due to failure to calculate the hidden quality costs. As the hidden quality costs provide indicators, they must be applied as required. Also, there is a task related to the risks surrounding the economic growth when it comes to the risk of losing market share. Similarly, the research found that these costs and disclosure, which affects the management of these costs effectively and objectively, are not measured and calculated by many of the industrial companies in Iraq

Integrated collaborative tools for precast supply chain management

Precast construction projects are associated with many activities, numerous parties, enormous effort, and different processes. For effective communication, this requires delivering appropriate and up-to-date information to enhance collaboration and improve integration. The purpose of this paper is to develop the system architecture and prototype of Context-Aware Cloud Computing Building Information Modelling (CACCBIM) for precast supply chain management. The findings of this research are grounded on the literature of cloud computing, context-awareness, building information modelling, and, ultimately, the analysis of interviews with stakeholders in precast construction. Findings determine that lack of integration, improper planning and scheduling, poor production timing, poor coordination, lack of good communication among parties, wrong deliveries, and poor control and supervision are the major issues within the precast supply chain. These issues could result in adverse consequences for the objectives and success of the precast project. Eventually, to reduce and eliminate these issues, the proposed prototype will support appropriate deliveries, efficient monitoring, facilitation of coordination, and collaboration with improved communication. It is anticipated that this research will establish a unique perception in the precast construction industry, which will finally enhance its productivity, improve its efficiency, and maximise its effectiveness