Current Shape Research Articles

Optimal pulse current shape for transient supercooling of thermoelectric cooler

This work developed a three-dimensional, multiphysics, and transient model to investigate transient supercooling of TECs (thermoelectric coolers). The model coupled the heat and electricity conductions and considered all thermoelectric effects. The model was well validated by dynamic test data for a TEC (Thermoelectric cooler) start-up process and was compared with the previous heat conduction model. The comparison confirmed that the multiphysics model has a more superior performance for predicting the key evaluation parameters of the transient supercooling. Then the model was used to investigate various current pulses (t0, t1/2, t1, t2, t3, t4, and t5) to search for the optimal shape. The results showed that the optimal shape is only determined by the time to reach the minimum cold end temperature (tmin) and the pulse width (τ). For the pulses with tmin < τ, a higher power pulse provides a lower cold end temperature, for the pulses with tmin = τ, however, the trend is opposite. The present results reasonably explain the divergence for the optimal pulse shape reported by the previous studies.

Shape and size controlled synthesis of Au nanorods: H2S gas-sensing characterizations and antibacterial application

Controlling their size and shape is one of the important issues in the fundamental study and application of colloidal metal nanoparticles. In the current study, different sizes and shapes of Au nanorods were fabricated using a seed-mediated growth method. Material characterization by X-ray diffraction and transmission electron microscopy revealed that the obtained products were made of single-crystal Au nanorods with an average diameter and length of 10nm and 40nm, respectively. The Au nanorod-based sensor exhibited significantly high sensitivity and fast response/recovery time to low concentrations (2.5–10ppm) of H2S at temperatures ranging from 300°C to 400°C. Additionally, they exhibited antibacterial effect at low concentration. These results suggested that the fabricated Au nanorods have excellent potential for practical application in air pollution monitoring and biomedicine.

Editorial

It is a matter of great pleasure to bring out the first issue of Bengal Journal of Psychiatry for the year 2015. Apart from original and review articles, we have included two CME articles: First one on “psychotropics in pregnancy” and the second one on “role of mindfulness in psychiatry”; both are of relevance to current post graduate trainees in psychiatry. We have also launched the long-awaited website for our journal (bengaljournalpsychiatry.org) which will strongly boost up the indexing process. The archiving of old issues of the journal and uploading them in the website is also being done. Once complete, this will help readers to access all issues of the journal from the website and individual articles will be downloadable. I would like to thank all the authors for their valuable contributions without which it would not have been possible to bring the journal in its current shape!

고속영역에서 전류형상에 따른 스위치드 릴럭턴스 발전기의 효율 개선

This paper describes about the efficiency improvement of switched reluctance generator (SRG) over the rated speed region. Since the current shape has a great influence on the loss of the machine, so the system efficiency can be improved by optimizing the current shape. In case the wide speed range application such as wind power and medium size hydraulic power generation, a method of switching angle control is suggested to obtain the wanted current shapes. In order to verify the method, the experimental platform is set up. The feasibility of the theory is verified by simulation and experimental results.

Characterizing generated charged inverse micelles with transient current measurements.

We investigate the generation of charged inverse micelles in nonpolar surfactant solutions relevant for applications such as electronic ink displays and liquid toners. When a voltage is applied across a thin layer of a nonpolar surfactant solution between planar electrodes, the generation of charged inverse micelles leads to a generation current. From current measurements it appears that such charged inverse micelles generated in the presence of an electric field behave differently compared to those present in equilibrium in the absence of a field. To examine the origin of this difference, transient current measurements in which the applied voltage is suddenly increased are used to measure the mobility and the amount of generated charged inverse micelles. The mobility and the corresponding hydrodynamic size are found to be similar to those of charged inverse micelles present in equilibrium, which indicates that other properties determine their different behavior. The amplitude and shape of the transient currents measured as a function of the surfactant concentration confirm that the charged inverse micelles are generated by bulk disproportionation. A theoretical model based on bulk disproportionation with simulations and analytical approximations is developed to analyze the experimental transient currents.

Catching a comet. Rosetta begins its comet tale. Introduction.

Catching a comet. Rosetta begins its comet tale. Introduction.

High Efficiency Operation of a Switched Reluctance Generator over a Wide Speed Range

This paper investigates the high efficiency operation of a switched reluctance generator over a wide speed range. The system efficiency is improved by optimizing the current shape. A modified angle position control (MAPC) method that can be used to optimize the current shape over a wide speed range is proposed. Simulation and experimental results are presented to validate the effectiveness of the proposed control scheme.

Aerodynamic Design Optimization of a Kind of Reentry Capsule Based on CFD and Multi-objective Genetic Algorithm

This paper presents a new kind of aerodynamic shape for reentry capsule, called spherical cap cubic curve segment(SCCS) shape, which is modeled by replacing the reversing cone segment of the traditional spherical cap segment-reversing cone(SCSC) shape with a more various cubic curve segment, however the spherical cap section is retained. In the assumed allowable axial range of centroid under a designed Mach number, a multi-point/objective design optimization mathematical programming model was established against aerodynamic static longitudinal stability characteristics, hypersonic lift-to-drag ratio characteristics under trim angle of attack and off-set location placement of gravity center for the above reentry capsule. Then the aerodynamic design optimization problem of the proposed reentry capsule was investigated through multi-objective genetic algorithm(MOGA) combined numeric parallel field simulation methods, and finally the optimal Pareto front was given. Comparing with the results of the SCSC shape in the literature[1], it shows that the optimal Pareto front of the current cubic curve shape has a wider distribution range relative to the counterparts of the segment-reversing cone shape, however both are relatively close in the overlapping area.

Computational modeling of anodic current distribution and anode shape change in aluminium reduction cells

In aluminium reduction cells, the profile of a new carbon anode changes with time before reaching a steady state shape, since the anode consumption rate, depending on the current density normal to anode surfaces, varies from one region to another. In this paper, a two-dimension model based on Laplace equation and Tafel equation was built up to calculate the secondary current distribution, and the shift of anode shape with time was simulated with arbitrary Lagrangian-Eulerian method. The time it takes to reach the steady shape for the anode increases with the enlargement of the width of the channels between the anodes or between the anode and the sidewall. This time can be shortened by making a sloped bottom or cutting off the lower corners of the new anode. Forming two slots in the bottom surface increases the anodic current density at the underside of the anode, but leads to the enlargement of the current at the side of the anode.

Satisfaction with Body Shape in College Students Comparisons by Gender

The purpose of the present study was to compare the scores on body shape (current, ideal and social) and body size dissatisfaction between men and women university mexican students. A total sample of 1488 participants, 735 women and 753 men, aged 18-26 years participated in this study. A quantitative approach with a descriptive and transversal survey design was used. All the participants completed the Contour Drawing Rating Scale. The results of the one-way multivariate analysis of variance, followed by the one-way univariate analyses of variance, showed that compared with the men, the women expressed a greater discrepancy between ideal and actual body shape and had higher score of social body shape and lower score of ideal body shape. However, in the current body shape statistically significant differences were not found. Because of the differences between men and women in their perception of body image found, these findings suggest that in order to design any intervention for improving the perceived body image of the students, the variable gender should be taken into account.

青年の痩身願望の性差，発達的変化に関する研究―現在の体型に関する損得感情および社会的比較からの検討―

青年の痩身願望の性差，発達的変化に関する研究―現在の体型に関する損得感情および社会的比較からの検討―

J0520401 パッケージエアコン4方向室内機における吹出し口の圧力損失低減

In order to reduce the fan power of a 4-way cassette type indoor unit of a packaged air conditioner, we developed the shape of air outlet nozzles reducing of the pressure-loss. The main cause of the pressure-loss was the flow separation area shaped in current air outlet nozzles. Therefore, we devised the shape for the control of the flow separation area. The shape was defined by two parameters, and the influence of parameters on the fan power reduction was surveyed by using the simulation technology with CFD (Computational Fluid Dynamics). We used the response surface which was made by results of CFD and approximate values with the Kriging-based method since the appropriate combination of parameters was efficiently searched from multiple parameters. As the result, the combination of parameters which reduces the fan power the most in the response surface was found. The shape adopted the combination of parameters can control the flow separation area. The fan power reduction by 9.9% in comparison with the current shape of air outlet nozzles was confirmed by the experiment.

3D skeleton construction by multi-view 2D images and 3D model segmentation

Issues regarding 3D object construction have been widely discussed for years. In order to simplify the process, we proposed a method to construct 3D object. Multi-view human images and feature points are used to generate 3D skeleton. We use an effective coordinate transformation method to transform feature points in 3D space. A modified K-means algorithm can search join points of target human by additional three directions and generate a simple 3D skeleton from the human's information. In 3D object segmentation, we use shape diameter-function SDF method and Gaussian mixture model GMM. We use SDF method to compute the SDF value by centre of shape information and neighbour of current shape path information. The GMM method is used to obtain the scope value of object clustering in our paper. Eventually, we show results of our method in experiment results, and results show that our method is effective.

STRESS AND FAILURE ANALYSIS OF RAPIDLY ROTATING ASTEROID (29075) 1950 DA

Rozitis et al. recently reported that near-Earth asteroid (29075) 1950 DA, whose bulk density ranges from 1.0 g/cm3 to 2.4 g/cm3, is a rubble pile and requires a cohesive strength of at least 44 Pa to 74 Pa to keep from failing due to its fast spin period. Since their technique for giving failure conditions required the averaged stress over the whole volume, it discarded information about the asteroid's failure mode and internal stress condition. This paper develops a finite element model and revisits the stress and failure analysis of 1950 DA. For the modeling, we do not consider material-hardening and softening. Under the assumption of an associated flow rule and uniform material distribution, we identify the deformation process of 1950 DA when its constant cohesion reaches the lowest value that keeps its current shape. The results show that to avoid structural failure the internal core requires a cohesive strength of at least 75 Pa - 85 Pa. It suggests that for the failure mode of this body, the internal core first fails structurally, followed by the surface region. This implies that if cohesion is constant over the whole volume, the equatorial ridge of 1950 DA results from a material flow going outward along the equatorial plane in the internal core, but not from a landslide as has been hypothesized. This has additional implications for the likely density of the interior of the body.

NEW LIGHT ON THELI JI禮記: THELI JIAND THE RELATED WARRING STATES PERIOD GUODIAN BAMBOO MANUSCRIPTS

AbstractThis article starts by examining how “Li ji” was used as a title in early China. In addition to theLi,Li jing,Shi li,Li yiandYi li, etc., “Li ji” was used as an alternative title for theLicanon, and the “Li” as a title was used to indicate what we now refer to as theLi jior theXiao Dai Li jias well. By discussing how the Guodian bamboo slip texts are related to the transmitted version of theLi ji, this article argues that the writing styles of the related excavated bamboo manuscripts are the particularLi gujing-orLi guji-styles, that the “Li gujing” or “Li guji” is more a description of those ancient retrieved texts than an actual title, and that many of the Guodian bamboo-slip texts are theLi guji- orLi gujing-style writings. According to theLi guji-styleZi yitext, it is evident that the material in theLi jicomes from creditable pre-Qin textual sources. Although theLi jitext came to its current shape as a result of later editing work, it does not mean that the receivedLi jisections have higher textual value than the excavated manuscripts do. On the contrary, the excavated manuscripts could have many valuable early textual sources that the transmittedLi jihas lost.

Body shape expectations and self-ideal body shape discrepancy in women seeking bariatric surgery: a cross-sectional study.

BackgroundPostoperative body shape expectations (BSE) of bariatric surgery candidates remain relatively unexplored, and may have important implications for weight loss outcomes, treatment satisfaction, and education.MethodsThe ‘Silhouette Figure Rating Scale’ was administered to 69 consecutive female candidates. Self-perceived current and goal body shape and postoperative BSE in four categories; “dream, “happy”, “acceptable”, and “disappointed” were examined.ResultsThe mean age and BMI of the sample was 43.4 ± 8.9 years and 48.8 ± 7.0 kg/m2. Self-ideal body shape discrepancy of 4.1 ± 1.3 silhouettes was reported, indicating body image dissatisfaction. 53% incorrectly identified the silhouette associated with their actual BMI. Goal body shape (4.3 ± 0.8 silhouettes) corresponded to a BMI figure 23.1 kg/m2- 26.2 kg/m2. The postoperative “dream” (4.1 ± 1.0 silhouettes), “happy” (5.0 ± 0.8 silhouettes), “acceptable” (5.3 ± 1.0 silhouettes), and “disappointed” (6.9 ± 1.0 silhouettes) BSE corresponded to silhouettes that were thinner than the thinnest silhouette clinically expected based on a 56.1% excess weight loss 1-year after laparoscopic sleeve gastrectomy (LSG) or a 22.3% to 47.2% total body weight loss.ConclusionsWomen seeking bariatric surgery experience body image dissatisfaction and misperceive their actual body size. BSE do not correspond with evidence-based LSG weight loss outcomes.

Active shape and vibration control for piezoelectric bonded composite structures using various geometric nonlinearities

This paper deals with simulations of the static and dynamic response, including shape and vibration control, for piezoelectric bonded smart structures using various geometrically nonlinear shell theories based on the first-order shear deformation (FOSD) hypothesis. The nonlinear theories include refined von Kármán nonlinear shell theory (RVK5), moderate rotation shell theory (MRT5), fully geometrically nonlinear shell theory with moderate rotations (LRT5), and fully geometrically nonlinear shell theory with large rotations (LRT56). The structures simulated are mainly comprised of cross-ply or angle-ply laminated thin-walled master structures bonded with isotropic piezoelectric layers or patches that are considered as actuators. Nonlinear finite element (FE) models are constructed for shape and vibration control of structures undergoing large displacements and rotations. Various plates and shells are validated by comparison with those reported in the literature, and then simulated for the current shape and vibration control. A widely used negative proportional velocity feedback control is adopted for the active vibration control. From the simulations, it can be concluded that large rotation theory should be considered for structures undergoing deformations beyond the range of moderate rotations. Additionally, the results show that by applying an appropriate voltage, a desired shape can be achieved, as well as the vibration can be significantly suppressed.

Inhibitory effects of cortisone and hydrocortisone on human Kv1.5 channel currents

Glucocorticoids are the primary hormones that respond to stress and protect organisms from dangerous situations. The glucocorticoids hydrocortisone and its dormant form, cortisone, affect the cardiovascular system with changes such as increased blood pressure and cardioprotection. Kv1.5 channels play a critical role in the maintenance of cellular membrane potential and are widely expressed in pancreatic β-cells, neurons, myocytes, and smooth muscle cells of the pulmonary vasculature. We examined the electrophysiological effects of both cortisone and hydrocortisone on human Kv1.5 channels expressed in Xenopus oocytes using a two-microelectrode voltage clamp technique. Both cortisone and hydrocortisone rapidly and irreversibly suppressed the amplitude of Kv1.5 channel current with IC50 values of 50.2±4.2μM and 33.4±3.2μM, respectively, while sustained the current trace shape of Kv1.5 current. The inhibitory effect of cortisone on Kv1.5 decreased progressively from −10mV to +30mV, while hydrocortisone׳s inhibition of the channel did not change across the same voltage range. Both cortisone and hydrocortisone blocked Kv1.5 channel currents in a non-use-dependent manner and neither altered the channel׳s steady-state activation or inactivation curves. These results show that cortisone and hydrocortisone inhibited Kv1.5 channel currents differently, and that Kv1.5 channels were more sensitive to hydrocortisone than to cortisone.

Body Weight Perception and Weight Control Behaviors among School Adolescents in Pulau Pinang

This study was conducted to determine the associations between body mass index (BMI), body weight perception and body shape among male and female adolescents. Besides, the aim of this study was to identify the differences in weight control behaviours between male and female adolescents. This cross- sectional study involved 194 subjects (98 males and 96 females) who were randomly selected from two secondary schools in Pulau Pinang. Subjects involved, were in the range of 16 and 17 years old. Information on socio-demographic, body image perception, body shape and weight control behaviors were obtained through questionnaires. Anthropometric measurements of body weight and height were also taken. Based on BMI categories (WHO, 2007), the results showed that 12.9% of the study subjects were classified as underweight, 55.2% normal weight, 17.5% overweight and 14.4% obese. The study found that the actual weight (BMI) of subjects were significantly associated to the body weight perception in overall and also for both sexes (p<0.05). There was a significant association between the selection of the current body shape and ideal body shape for both sexes (p<0.05). BSQ scores also showed a significant association with actual weight (BMI) for both sexes (p<0.05). This study showed that there was a significant association between males and females (p<0.05) based only on 2 out of 12 items of healthy weight control behaviors used in food diet and increasing physical activity. While for the 3 out of 9 items of unhealthy weight control behaviors used in skipping meals, starting the use of tobaccos and fasting, the study showed that there was a significant association between the sexes (p<0.05). Therefore, by understanding the reasons for gender differences in the actual weight and weight perceptions, it could assist health professionals in helping a person to make a strategic decision to control body weight thus could help avoid the risk of eating disorders.

Effect of electron extraction from a grid plasma cathode on the generation of emission plasma

The paper describes the operating mode of a plasma electron source based on a low- pressure arc discharge with grid stabilization of the plasma emission boundary which provides a considerable (up to twofold) increase in discharge and beam currents at an Ar pressure in the vacuum chamber p = 0.02-0.05 Pa, accelerating voltages of up to U = 10 kV, and longitudinal magnetic field of up to Bz = 0.1 T. The discharge and beam currents are increased on electron extraction from the emission plasma through meshes of a fine metal grid due to the energy of a high-voltage power supply which ensures electron emission and acceleration. The electron emission from the plasma cathode and arrival of ions from the acceleration gap in the discharge changes the discharge plasma parameters near the emission grid, thus changing the potential of the emission grid electrode with respect to the discharge cathode. The load is not typical and changes the voltage polarity of the electrode gap connected to the discharge power supply, which is to be taken into account in its calculation and design. The effect of electron emission from the plasma cathode on the discharge system can not only change the discharge and beam current pulse shapes but can also lead to a breakdown of the acceleration gap and failure of semiconductor elements in the discharge power supply unit.