Tradeoffs for number-squeezing in collisions of Bose-Einstein condensates

We investigate the factors that influence the usefulness of supersonic collisions of Bose-Einstein condensates as a potential source of entangled atomic pairs by analyzing the reduction of the number difference fluctuations between regions of opposite momenta. We show that non-monochromaticity of the mother clouds is typically the leading limitation on number squeezing, and that the squeezing becomes less robust to this effect as the density of pairs grows. We develop a simple model that explains the relationship between density correlations and the number squeezing, allows one to estimate the squeezing from properties of the correlation peaks, and shows how the multi-mode nature of the scattering must be taken into account to understand the behavior of the pairing. We analyze the impact of the Bose enhancement on the number squeezing, by introducing a simplified low-gain model. We conclude that as far as squeezing is concerned the preferable configuration occurs when atoms are scattered not uniformly but rather into two well separated regions.Comment: 13 pages, 13 figures, final versio

Raman scattering of atoms from a quasi-condensate in a perturbative regime

It is demonstrated that measurements of positions of atoms scattered from a quasi-condensate in a Raman process provide information on the temperature of the parent cloud. In particular, the widths of the density and second order correlation functions are sensitive to the phase fluctuations induced by non-zero temperature of the quasi-condensate. It is also shown how these widths evolve during expansion of the cloud of scattered atoms. These results are useful for planning future Raman scattering experiments and indicate the degree of spatial resolution of atom-position measurements necessary to detect the temperature dependence of the quasi-condensate.Comment: 8 pages, 8 figure

The application of fault signature analysis in Tenaga Nasional Berhad Malaysia

Unplanned electrical power outages are a major concern to power utilities throughout the whole world. Unfortunately, power outages will continue to occur and they cannot be fully prevented. It could be the result of lightning strikes, tree encroachment, or equipment failure. However, the impact can be reduced if power system operators are equipped with the appropriate tools to analyze the root cause of the failure. Without sufficient tools to identify the nature of a fault, the restoration process could be delayed because the operator does not know whether it is safe to normalize the isolated line. This paper describes the new and simplified fault signature analysis approach on Tenaga Nasional Berhad using a digital fault recorder. The research focuses on the contribution of the lightning strike and tree encroachment to the overhead line tripping in Malaysi

Development of flexible pavement design tool based on Jabatan Kerja Raya (JKR)’s revised guideline/ Mohamad Irwan P. Harahap

Land and road transport system provides a vital artery of communication, commerce and trade that helps to propel Malaysia towards national rapid growth, modernization and prosperity. In order to ensure standardization and compliance to the sanctioned road construction practice in the country, the Arahan Teknik (Jalan) 5/85 had been introduced and used extensively by the engineering community since 1985 for most of the road pavement design needs. However, over the years the guideline was incompatible with the technological advancement in the area, and consequently it suffers from design inadequacy and inflexibility, and lack of functionality and safety. Since 2013 however, Jabatan Kerja Raya Malaysia (JKR) has introduced the new Arahan Teknik (Jalan) 5/85 (Pindaan 2013) that is technically con-current and relevant to prevailing circumstances through incorporation of state-of-the-art technological developments in road pavement construction from across the world while addressing many a shortcoming of the former guideline. As in many an application in the industry as well as academia, migration to a new thinking or work process would be greatly facilitated and expedited with the aid of ICT tools. Excel VBA (Visual Basic for Application) provides such a familiar, common and convenient platform to develop the occasionally intensive and quite engaging computational processes but with the look and feel of commercial software and at a fraction of the cost, and practically reutilizing existing resources. Such development was addressed in this paper and used to solve a real world project, the results of which were in agreement with manual computations. Furthermore, the functionality and flexibility of the program would allow for multiple scenario investigation and comparison that would facilitate optimized design solutio

Pulmonary Emphysema Regional Distribution and Extent Assessed by Chest Computed Tomography Is Associated With Pulmonary Function Impairment in Patients With COPD

Objective: This study aimed to evaluate how emphysema extent and its regional distribution quantified by chest CT are associated with clinical and functional severity in patients with chronic obstructive pulmonary disease (COPD). Methods/Design: Patients with a post-bronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) < 0.70, without any other obstructive airway disease, who presented radiological evidence of emphysema on visual CT inspection were retrospectively enrolled. A Quantitative Lung Imaging (QUALI) system automatically quantified the volume of pulmonary emphysema and adjusted this volume to the measured (EmphCTLV) or predicted total lung volume (TLV) (EmphPLV) and assessed its regional distribution based on an artificial neural network (ANN) trained for this purpose. Additionally, the percentage of lung volume occupied by low-attenuation areas (LAA) was computed by dividing the total volume of regions with attenuation lower or equal to -950 Hounsfield units (HU) by the predicted [LAA (%PLV)] or measured CT lung volume [LAA (%CTLV)]. The LAA was then compared with the QUALI emphysema estimations. The association between emphysema extension and its regional distribution with pulmonary function impairment was then assessed. Results: In this study, 86 patients fulfilled the inclusion criteria. Both EmphCTLV and EmphPLV were significantly lower than the LAA indices independently of emphysema severity. CT-derived TLV significantly increased with emphysema severity (from 6,143 ± 1,295 up to 7,659 ± 1,264 ml from mild to very severe emphysema, p < 0.005) and thus, both EmphCTLV and LAA significantly underestimated emphysema extent when compared with those values adjusted to the predicted lung volume. All CT-derived emphysema indices presented moderate to strong correlations with residual volume (RV) (with correlations ranging from 0.61 to 0.66), total lung capacity (TLC) (from 0.51 to 0.59), and FEV1 (~0.6) and diffusing capacity for carbon monoxide DLCO (~0.6). The values of FEV1 and DLCO were significantly lower, and RV (p < 0.001) and TLC (p < 0.001) were significantly higher with the increasing emphysema extent and when emphysematous areas homogeneously affected the lungs. Conclusions: Emphysema volume must be referred to the predicted and not to the measured lung volume when assessing the CT-derived emphysema extension. Pulmonary function impairment was greater in patients with higher emphysema volumes and with a more homogeneous emphysema distribution. Further studies are still necessary to assess the significance of CTpLV in the clinical and research fields.This research was supported by the Brazilian Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Grants Nos. 302702/2017-2 and 302839/2017-8) and the Rio de Janeiro State Research Supporting Foundation (Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro, Grants Nos. E-26/211.867/2016, E-26/202.785/2017, E-26/203.001/2018), and by national funds through FCT, Cardiovascular R&D Center – UnIC (UIDB/00051/2020 and UIDP/00051/2020)

Effect of cross-country fault of distance protection in transmission line with different voltage levels

Transmission overhead line is one of the main elements in electric power system. Electrical power system comprises of generation, transmission and distribution. For transmission lines, it is used to transmit electric power to large load center. Nowadays, double circuit transmission lines on the same tower with a different voltage are widely used. This paper present the studies of the effect on distance protection, when fault that occur in the transmission line that have different voltages in the same tower. In this situation, PSCAD/EMTDC software has been used to simulate the output current and voltages in order to see the fault effect on distance protection. In the other words, the PSCAD/EMTDC software is used in model and analysis of the effect of cross-country fault on distance protection. In this paper, the result of cross-country fault on distance protection with different voltage levels is presented