15,658 research outputs found
Multireference linearized coupled cluster theory for strongly correlated systems using matrix product states.
We propose a multireference linearized coupled cluster theory using matrix product states (MPSs-LCC) which provides remarkably accurate ground-state energies, at a computational cost that has the same scaling as multireference configuration interaction singles and doubles, for a wide variety of electronic Hamiltonians. These range from first-row dimers at equilibrium and stretched geometries to highly multireference systems such as the chromium dimer and lattice models such as periodic two-dimensional 1-band and 3-band Hubbard models. The MPS-LCC theory shows a speed up of several orders of magnitude over the usual Density Matrix Renormalization Group (DMRG) algorithm while delivering energies in excellent agreement with converged DMRG calculations. Also, in all the benchmark calculations presented here, MPS-LCC outperformed the commonly used multi-reference quantum chemistry methods in some cases giving energies in excess of an order of magnitude more accurate. As a size-extensive method that can treat large active spaces, MPS-LCC opens up the use of multireference quantum chemical techniques in strongly correlated ab initio Hamiltonians, including two- and three-dimensional solids
Can brand personality differentiate fast food restaurants?
This study examines brand personality as an approach to establish brand differentiation in the highly competitive fast food sector. A modified brand personality scale proposed by Musante et al. (2008) was used to develop a questionnaire which was distributed to customers to assess their perceived brand personalities for three well known fast food restaurants – McDonald’s, KFC and Subway. The results demonstrated that even though the overall perceived brand personality was different for all three brands, no individual personality dimension characterised any of the brands.Keywords: brand, brand personality, fast food, restaurant
Impact Analysis of JellyFish Attack in MANETs
MANETs or Mobile Ad Hoc Networks is a network that consists of mobile nodes, is selforganizing and short lived. Due to the openness, decentralized and infrastructure less architecture it can be prone to different types of attacks. One such attack is the JellyFish attack. It is a type of passive attack .It is very difficult to detect this attack as it complies with the protocols. In this paper we present a study on this attack and its variants. The first section gives a brief introduction on MANETs and the different types of attacks on it from different point of view. The later section we concentrate on the JellyFish Attack. Further a review on the analysis is carried out from different sources to understand the impact of this attack on the performance and its effect on the network.Keywords: Active attacks, Passive Attacks, JellyFish Attack, AODV, DSR, TORA, GR
Cadmium Sulfide-buffered PV Systems: Assessing the Environmental, Health, and Economic Impacts
As the world’s population continues to grow, global energy crises are expected to rise in the future, thus accelerating the demand for renewable energy technology, particularly solar photovoltaics. The energy sector will face an increasingly complex array of interlocking challenges - technological, environmental, health, economic, and regulatory. In this paper, we study CdS, a widely used buffer material in thin film photovoltaics, to assess and monetize environmental, health, and socio-economic externalities associated with the use of the material. Currently, CdS has a significant advantage over other alternate buffer materials in terms of efficiency and low-cost production of large-area processing of thin films, but the potential environmental risks associated with the use of cadmium are of concern. We quantified the environmental, human health, and socio-economic impacts of cadmium emissions from CdS-buffered PV system. In addition, this paper provides a comprehensive outlook of the past, current, and future global market growth rate of thin film photovoltaic technologies
Case Histories of Earthen Dam Failures
Historical study of dams conceived in earlier times is essential. To continue advancing, the engineering profession must periodically review past problems and the lessons that they taught. Candid sharing of information on failures as well as successes is needed. In fact, some of the most valuable learning has come from projects where errors have been clear in retrospect. In recent years, dam safety has drawn increasing attention from the public. This is because floods resulting from breaching of dams can lead to devastating disasters with tremendous loss of life and property, especially in densely populated areas. Past dam failure disasters showed that the loss of life in the event of a dam failure is directly related to the warning time available to evacuate the population at risk downstream of the dam. Earth and rock fill dams are widely used throughout the world, and most of the dam failures involve such dams. To speak about failures of dams without a brief account of these happenings in the dam world is not possible. Therefore, it is essential to go through the case histories of such dam failures to understand the causes of failures of the dams failed in the past. The main causes of failures of such dams are attributed to overtopping, internal erosion and piping. There are excellent sources and case studies are available in the literature related to failure of the earthen dams due to overtopping, internal erosion and piping. The purpose of this paper is to highlight the most promising causes of the earthen dam failures and present the case histories of the dams failed in the world due to these causes. The case histories reported in this paper are chosen not for the entity of the damage occurred, but are representative of the body of knowledge that has been accumulated in the interest of the future safety of dams
A New Method Development and Validation of 5α Reductase Inhibitor (Dutasteride) Using R-HPLC In Bulk and Pharmaceutical Dosage Form (Dexamethasone Use as An Internal Standard)
The proposed HPLC Method was found to be simple,precise,accurate and economicalfor the estimation of dutasteride in Bulk and tablet dosage form. The present work, developed HPLC method was found suitable and validated. Luna – C-18 (250 mm x 4.6 mm, 20 µL) column was used for the assay. Mobile phase was Acetonitrile and Water in the ratio 80:20. Linearity was established in the range of 5-100 µg/ml with a coefficient correlation of 0.9998 and eluents were monitored at 242 nm and at 1 ml/min. flow rate. The Retention time was found to be 5.9 min. The efficiency of the column, expressed as the number of theoretical plates for six replicate injections was 11566 ± 119.695 (%CV1.03%) and USP tailing factor was 1.25 ± 0.012 (%CV 0.79). The regression equation for the calibration plot was Y = 0.0618 X – 0.008. Intra-day precision from 0.166 to 1.449 and Inter-day precision from 0.186 to 1.449. The% recovery of dutasteride from API and dosage form were 100.70% and 99.66%. The drug was subjected to stress conditions such as Oxidative and Photodegradation, Considerable degradation was found to occure in acidic and basic medium on heating at 100°C but no degradation was observed at room temperature. The drug was exposed to 10% H2O2{heating at 100°C forming degradation product at RT: 2.557}. The LOD and LOQ was 0.257µg and 0.779 µg respectively.When the flow rate was reduced, the retention time of dutasteride increased.The assay result with analyst #1 and Analyst #2 were % Assay = 98.40% (%RSD = 0.13%) and % Assay = 99.07% (%RSD =0.53) respectively. Robustness and ruggednesswasobserved that results were well within acceptance limits of 98–102%, with %RSD ±2.0%, indicating the method is rugged and provides consistent and reliable results which are not affected by small changes in experimental conditions. This method can be used for routine analysis of dutasteride. Running Title: A New Method Development and Validation of 5α-Reductase inhibitor using R-HPLC
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