Influence of analysis and design models on minimum weight design

The results of numerical experiments designed to illustrate how the minimum weight design, accuracy, and cost can be influenced by: (1) refinement of the finite element analysis model and associated load path problems, and (2) refinement of the design variable linking model are examined. The numerical experiments range from simple structures where the modelling decisions are relatively obvious and less costly to the more complex structures where such decisions are less obvious and more costly. All numerical experiments used employ the dual formulation in ACCESS-3 computer program. Guidelines are suggested for creating analysis and design models that predict a minimum weight structure with greater accuracy and less cost. These guidelines can be useful in an interactive optimization environment and in the design of heuristic rules for the development of knowledge-based expert optimization systems

Experimental evidence on promotion of electric and improved biomass cookstoves.

Improved cookstoves (ICS) can deliver "triple wins" by improving household health, local environments, and global climate. Yet their potential is in doubt because of low and slow diffusion, likely because of constraints imposed by differences in culture, geography, institutions, and missing markets. We offer insights about this challenge based on a multiyear, multiphase study with nearly 1,000 households in the Indian Himalayas. In phase I, we combined desk reviews, simulations, and focus groups to diagnose barriers to ICS adoption. In phase II, we implemented a set of pilots to simulate a mature market and designed an intervention that upgraded the supply chain (combining marketing and home delivery), provided rebates and financing to lower income and liquidity constraints, and allowed households a choice among ICS. In phase III, we used findings from these pilots to implement a field experiment to rigorously test whether this combination of upgraded supply and demand promotion stimulates adoption. The experiment showed that, compared with zero purchase in control villages, over half of intervention households bought an ICS, although demand was highly price-sensitive. Demand was at least twice as high for electric stoves relative to biomass ICS. Even among households that received a negligible price discount, the upgraded supply chain alone induced a 28 percentage-point increase in ICS ownership. Although the bundled intervention is resource-intensive, the full costs are lower than the social benefits of ICS promotion. Our findings suggest that market analysis, robust supply chains, and price discounts are critical for ICS diffusion

Observation of a 2D Bose-gas: from thermal to quasi-condensate to superfluid

We present experimental results on a Bose gas in a quasi-2D geometry near the Berezinskii, Kosterlitz and Thouless (BKT) transition temperature. By measuring the density profile, \textit{in situ} and after time of flight, and the coherence length, we identify different states of the gas. In particular, we observe that the gas develops a bimodal distribution without long range order. In this state, the gas presents a longer coherence length than the thermal cloud; it is quasi-condensed but is not superfluid. Experimental evidence indicates that we observe the superfluid transition (BKT transition).Comment: 5 pages, 6 figure

Effects of quarry blasting towards the residential area at Kangkar Pulai, Johor, Malaysia

The drill and blast technique have been widely used recently due to demand for natural building materials like rock aggregates. However, the intensity of blasting effects has been questioned on its validity towards the nearby residential areas. In this study, the blasting effects from Quarry A and B has been assessed based on constant location of the residential areas (Taman Pulai Hijauan and Taman Bandar Baru Kangkar Pulai, respectively) using the empirical formulations only. The blasting effects are highly dependent on the maximum instantaneous charge in blast holes (Q) which are dependent on parameters like number of blast holes, charge per column, Powder Factor and number of blast per delay. This study was able to show that with an increase of the independent variables, the Q value rises significantly. The average Q value from Quarry A (181.07 kg) was slightly higher than Quarry B (180.22 kg). The correlations made for each quarry showed that Quarry A had a better regression line with lower standard error due to the high number of blast data obtained during the monitoring period of about 1 year and 8 months. Meanwhile, the impact assessments showed higher PPV (Peak Particle Velocity) value at higher Q holding blast holes in Quarry A compared to Quarry B and decreases with increasing distance. The similar relationship was observed for the air blast assessments. Yet, all of the blasts produced are relatively within safe limits which are less than 5 mm/s Mineral & Geosciences Department (JMG) and less than 125 dBL United States Bureau of Mining (USBM). Thus, extra precaution can be taken by estimating the suitable Q value such as A (97.66 kg) and B (271.68 to 495.01 kg) to maintain safe blasting operations and prevent damages to the nearby residential areas

Hydrodynamic approach to coherent nuclear spin transport

We develop a linear response formalism for nuclear spin diffusion in a dipolar coupled solid. The theory applies to the high-temperature, long-wavelength regime studied in the recent experiments of Boutis et al. [Phys. Rev. Lett. 92, 137201 (2004)], which provided direct measurement of interspin energy diffusion in such a system. A systematic expansion of Kubo's formula in the flip-flop term of the Hamiltonian is used to calculate the diffusion coefficients. We show that this approach is equivalent to the method of Lowe and Gade [Phys. Rev. 156, 817 (1967)] and Kaplan [Phys. Rev. B 2, 4578 (1970)], but has several calculational and conceptual advantages. Although the lowest orders in this expansion agree with the experimental results for magnetization diffusion, this is not the case for energy diffusion. Possible reasons for this disparity are suggested.Comment: 7 pages, REVTeX4; Published Versio

Relative communicators: evaluation of an innovative hospital role emerging from the Covid-19 pandemic

Background: During the COVID-19 pandemic, hospital visiting policies made communication challenging. Effective communication is known to reduce anxiety for patients and relatives, and improve trust in healthcare services. We describe an innovative project in which students and staff were deployed to the role of ‘Relative Communicators’, enabling routine updates and facilitating video calls between patients and their next of kin (NOK). The aim of our project was to explore NOK's perceptions of communication about their inpatient relatives and the Relative Communicators. // Method: Participants were asked to complete a structured interview over a telephone call but could use the online form if this was not possible. Hence, we obtained data using a combination of interviews and online surveys. NOK, who utilized the relative communicator service (n = 30), were surveyed. Quantitative data and free-text responses were analysed to understand their perceptions. // Results: 85.7% of respondents (24/28) were satisfied with information they received from Relative Communicators. 43.3% (13/30) of NOK felt they could communicate with their relative ‘the right amount’, and 56.7% (17/30) felt they were sufficiently involved in care decisions. Qualitative data provided further insights around the demand for proactive updates, frustration with existing communication models, and praise of telecommunication methods. // Conclusions: We suggest proactive updates and telecommunication could improve the experience for patients and NOK. Relative Communicators provided a bridge for inpatients and NOK to connect. The pandemic has exacerbated systemic communication issues and innovations, such as the Relative Communicators, may help to address these challenges

The relationship between sonographic parameters of brachial artery and smoking

Background Anatomical changes in brachial artery like thickening of initima-media thickness (IMT) has shown to significantly associated with progression of atherosclerosis. This changes will ultimately lead to manifestation of cardiac vascular disease like coronary artery disease and stroke, which causes 17.3 millions of death cases worldwide, in both developed and developing countries. The number of death cases will continue to increase if preventive measure is not taken to control the risk factors associated with the atherosclerosis. The high-resolution sonography has shown to be a non-invasive and radiation-free clinical tools in measuring IMT value of artery, which provide insight to the progression of atherosclerosis in high risk group including smokers. Aim and Objective The present study aimed to determine the association between sonography parameters of the brachial artery and smoking. Method High resolution ultrasonography was used to examine the brachial artery among smoker and non-smokers, which recruited from the staff of Hospital Universiti Sains Malaysia. The brachial artery is scanned in the antecubital fossa in a longitudinal fashion. Optimal brachial artery images were obtained at about 5-10 cm above the antecubital crease. This location was marked, and all subsequent images were obtained at the same location. The IMT at the far wall is measured directly as the distance between the lumen-intima and media-adventitia border at the distal portions of the brachial (5-10cm above elbow). Measurement of PSV and RI are taken. Doppler angle is keep at <60º. Result There were 45 staff of Hospital Universiti Sains Malaysia (HUSM) volunteered to participate in this study. Among these participants, 20 (44.4%) of them were smokers while 25 (55.6%) of them were non-smokers. The mean of the intimal media thickness is 0.36±0.01 mm for smokers and 0.30±0.01 mm for non-smokers. The mean of the peak systolic velocity is 57.50±14.79 cm/sec for smokers and 48.94±5.19 cm/sec for non-smokers. The mean of the resistive index is 0.90±0.03 for smokers and 0.85±0.13 for non-smokers. There is significant difference of brachial artery intimal media thickness and resistive index between smokers and non-smokers (p<0.01), but not the peak systolic value. Among the two significant variables, only intimal media thickness and duration of smoking showed significant correlation and regression (r=0.754; r2=0.568, p<0.01). Conclusion The present study revealed significant thickening of IMT in smokers compared to nonsmokers among HUSM staff. This suggested the application of high resolution ultrasonography in screening of IMT among smokers, which is consider as high risk group for atherosclerosis

Non-Markovian decay and dynamics of decoherence in private and public environments

We study the decay process in an open system, emphasizing on the relevance of the environment's spectral structure. Non-Markovian effects are included to quantitatively analyze the degradation rate of the coherent evolution. The way in which a two level system is coupled to different environments is specifically addressed: multiple connections to a single bath (public environment)or single connections to multiple baths (private environments). We numerically evaluate the decay rate of a local excitation by using the Survival Probability and the Loschmidt Echo. These rates are compared to analytical results obtained from the standard Fermi Golden Rule (FGR) in Wide Band Approximation, and a Self-Consistent evaluation that accounts for the bath's memory in cases where an exact analytical solution is possible. We observe that the correlations appearing in a public bath introduce further deviations from the FGR as compared with a private bath.Comment: 18 pages, 7 figures. Accepted for publication in Physical Review

Phase fluctuations in anisotropic Bose condensates: from cigars to rings

We study the phase-fluctuating condensate regime of ultra-cold atoms trapped in a ring-shaped trap geometry, which has been realized in recent experiments. We first consider a simplified box geometry, in which we identify the conditions to create a state that is dominated by thermal phase-fluctuations, and then explore the experimental ring geometry. In both cases we demonstrate that the requirement for strong phase fluctuations can be expressed in terms of the total number of atoms and the geometric length scales of the trap only. For the ring-shaped trap we discuss the zero temperature limit in which a condensate is realized where the phase is fluctuating due to interactions and quantum fluctuations. We also address possible ways of detecting the phase fluctuating regime in ring condensates.Comment: 10 pages, 5 figures, minor edit