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Background: Inguinal hernia repair is the most frequently performed operation in general surgery. The standard method for inguinal hernia repair had changed little over a hundred years until the introduction of synthetic mesh. This mesh can be placed by either using an open approach or by using a minimal access laparoscopic technique. Objectives: The purpose of the present study was to compare minimal access laparoscopic mesh techniques with open techniques in hernioplasty. Methodology: This pragmatic randomized control trial was conducted in the Department of Surgery at Shaheed Suhrawardy Medical College & Hospital, Dhaka from January 2014 to December 2015 for a period of two years. Patients at any age with both sexes who were presented with inguinal hernia were selected as study population. These patients were divided into two group designated as group A and group B. In group A inguinal hernia repair was performed by laparoscopic technique and in group B open technique was used to repair the inguinal hernia. The comparison was done between open and laparoscopic technique of inguinal hernia repair in terms of duration of operation, per-operative complication, immediate post-operative pain, numbness, duration of hospital stay and time of return to normal activities. Follow up was done from 6 months to 2 years. Results: A total number of 200 patients were recruited for repairing of inguinal hernia. Duration of operation was longer initially in the laparoscopic groups (Laparoscopic approach 90 min vs. Lichtenstein approach 60 min). Post-operative pain was another important outcome to consider when choosing between laparoscopic and open repair of inguinal hernia. Laparoscopic repair had been associated with less post-operative pain than open repair. Operative complications were uncommon for both methods. Length of hospital stay was little shorter in laparoscopic group (laparoscopic 1-2 days vs. open technique 3-4 days); however, return to usual activity was earlier for laparoscopic groups (7 days) where open group: 20-30 days. The data available showed less persisting pain (Overall 8/80 versus 12/100) and less persisting numbness (Overall 3/80 versus 7/100) in the laparoscopic groups. Conclusions: In conclusion, minimal access laparoscopic mesh technique is better than open techniques in inguinal hernia repair. Journal of National Institute of Neurosciences Bangladesh, January 2021, Vol. 7, No. 1, pp. 75-78

Supercapacitors are receiving significant interest in wireless sensor network applications due to their high power density and longer lifespan. In such applications, consideration of the leakage effect is crucial for online control and management of supercapacitors. Motivated by this fact, in this paper we propose an online scheme to estimate the state-of-charge (SOC) of supercapacitors, taking the leakage effect into account. First, we propose a completely observable equivalent circuit model (ECM) of a supercapacitor, which captures the leakage effect. Then, we design an unscented-Kalman-filter-based SOC estimator on the proposed ECM. To illustrate the proposed scheme, we consider a commercially available 5 F supercapacitor (Maxwell BCAP0005) and conduct experimental studies to identify the ECM parameters. We also perform simulation and experimental studies to test the effectiveness of the proposed estimation scheme, in this paper. Finally, we evaluate the robustness of the proposed scheme under parametric and measurement uncertainties.

Accurate state-of-Charge (SOC) estimation of supercapacitor is very crucial for real-time energy management and control of the energy storage device. This paper deals with performance comparison and analysis of the two most commonly used SOC estimators, namely Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) for remaining charge monitoring of supercapacitors. For that purpose, a completely observable equivalent circuit model of supercapacitor has been adopted in order to design the estimation algorithms. In order to perform the comparative analysis, a commercially available Maxwell supercapacitor has been chosen to conduct experimental studies. Finally, The performance of the estimators has been illustrated via both the single-run and the Monte Carlo runs.

International audience; The primordial scalar power spectrum is well constrained by the cosmological data on large scales, primarily from the observations of the anisotropies in the cosmic microwave background. Over the last few years, it has been recognized that a sharp rise in power on small scales will lead to the enhanced formation of primordial black holes (PBHs) and also generate secondary gravitational waves (GWs) of higher and, possibly, detectable amplitudes. It is well understood that scalar power spectra with COBE normalized amplitude on the cosmic microwave background scales and enhanced amplitudes on smaller scales can be generated due to deviations from slow roll in single, canonical scalar field models of inflation. In fact, an epoch of so-called ultraslow roll inflation can lead to the desired amplification. We find that scenarios that lead to ultraslow roll can be broadly classified into two types, one wherein there is a brief departure from inflation (a scenario referred to as punctuated inflation) and another wherein such a departure does not arise. In this work, we consider a set of single field inflationary models involving the canonical scalar field that lead to ultraslow roll and punctuated inflation and examine the formation of PBHs as well as the generation of secondary GWs in these models. Apart from considering specific models, we reconstruct potentials from certain functional choices of the first slow roll parameter leading to ultraslow roll and punctuated inflation and investigate their observational signatures. In addition to the secondary tensor power spectrum, we calculate the secondary tensor bispectrum in the equilateral limit in these scenarios. Moreover, we calculate the inflationary scalar bispectrum that arises in all the cases and discuss the imprints of the scalar non-Gaussianities on the extent of PBHs formed and the amplitude of the secondary GWs generated. We conclude with a discussion on the wider implications of our results.

One of the important parameters in cosmology is the parameter characterizing the equation of state (EoS) of the sources driving the cosmic expansion. Epochs that are dominated by radiation, matter, or scalar fields, whether they are probed either directly or indirectly, can be characterised by a unique value of this parameter. However, the EoS parameter during reheating---a phase succeeding inflation which is supposed to rapidly defrost our universe---remains to be understood satisfactorily. In order to circumvent the complexity of defining an instantaneous EoS parameter during reheating, an effective parameter $w_\mathrm{eff}$, which is an average of the EoS parameter over the duration of reheating, is usually considered. The value of $w_\mathrm{eff}$ is often chosen arbitrarily to lie in the range $-1/3 \leq w_\mathrm{eff} \leq 1$. In this work, we consider the time evolution of the EoS parameter during reheating and relate it to inflationary potentials $V(\phi)$ that behave as $\phi^p$ around the minimum, a proposal which can be applied to a wide class of inflationary models. We find that, given the index $p$, the effective EoS parameter $w_{\rm eff}$ is determined uniquely. We discuss the corresponding effects on the reheating temperature and its implications., Comment: v1: 10 pages, 5 figures; v2: 13 pages, 7 figures, discussions and references added, version to apprear in Phys. Rev. D

We propose a two-phase reheating scenario where the initial preheating dynamics is described by an effective dynamics followed by the standard perturbative reheating. Some of the important universal results of lattice simulation during preheating have been considered as crucial inputs in our two-phase dynamics. In this framework, detailed phenomenological constraints have been obtained on the inflaton couplings with reheating fields, and dark matter parameters in terms of CMB constrained inflationary scalar spectral index. It is observed that the conventional reheating scenario generically predicts the maximum reheating temperature $T_{re}^{max} \simeq 10^{15}$ GeV, corresponding to an almost instantaneous transition from the end of inflation to radiation domination. This fact will naturally lead to the problem of non-perturbative inflaton decay, which is in direct conflict with the perturbative reheating itself. Taking into account this by incorporating effective non-perturbative dynamics as the initial phase, our model of two-phase reheating scenarios also predicts model-independent maximum reheating temperature, which does not correspond to the instantaneous process. Further, $T_{re}^{max}$ is predicted to lie within $(10^{13}, 10^{10})$ GeV if CMB constraints on inflaton couplings with different reheating field are taken into account. We have further studied in detail the dark matter phenomenology in a model-independent manner and show how dark matter parameter space can be constrained through CMB parameters via the inflaton spectral index. Considering dark matter production during reheating via the Freeze-in mechanism, its parameter space has been observed to be highly constrained by our two-phase reheating than the constraints predicted by the conventional reheating scenarios, which are believed to theoretically incomplete., 63 pages, 29 figures, An expanded version of this paper arxiv number: 1709.00251

Solid pseudopapillary neoplasm of pancreas (SPN) is a rare entity; therefore proper diagnosis, evaluation and formulation of treatment protocols is difficult. The commonest presenting symptom is abdominal pain. This article presents a case of solid pseudopapillary neoplasm of pancreas in a 35 years old lady. A high index of clinical suspicion is necessary to suspect and diagnose SPN. This diagnosis should be borne in mind when young female patients present with a pancreatic mass.J Shaheed Suhrawardy Med Coll, June 2017, Vol.9(1); 31-34

Background: Congenital heart diseases (CHD) are one of the most common developmental errors in humans.Objectives: The purpose of the present study was to see the frequencies of various types of atrial septal defect (ASD) and associated cardiovascular disorders in patients undergoing surgical repair.Methodology: This cross-sectional study was conducted on patients undergoing surgical repair at the National Institute of Cardiovascular Diseases (NICVD) or the National Heart Foundation and Research Institute (NHF & RI) in Dhaka, during the period of July, 2010 to June, 2011. Patients presented with ASD at any age of both sexes were selected as study population. Diagnoses were revealed with echocardiography and confirmed preoperatively by registered cardiac surgeons.Results: The morphological types of ASD were ostium secundum type in 96% cases and sinus venosus type in 4% cases. Atrial septal defects were either small or larger defects associated with pulmonary hypertension in 38 (76%) cases, varying degree of tricuspid regurgitation was seen in 33 (66%) patients and dilated pulmonary artery was noted in 24 (48%) cases. Ventricular septal defect in 4 (8%) cases, tricuspid atresia in 2 (4%) cases and mitral valve prolapse in 6 (12%) cases were also observed.Conclusions: Ostium secundum type of ASD is found to be the commonest type of ASDJournal of Current and Advance Medical Research 2018;5(2):60-63

Reuse of the retired/aged supercapacitors plays an important role in production sustainability and environmental concerns. Therefore, appropriate health characterization methods along with proper guidelines to identify the remaining useful capacitance of the retired supercapacitor cells are required. This paper focuses on conventional approach based capacitance diagnosis of retired supercapacitors, since there is a lack of technological development for the same. In particular, we evaluate the effectiveness of Maxwell six-step process-based time domain approach and electrochemical impedance spectroscopy based frequency domain approach in identifying the remaining capacitance of the retired supercapacitors. This work considers a retired cell of the commercially available Maxwell supercapacitors to demonstrate the approach. The results obtained from the conventional approaches via cyclic voltammetry test is validated. Subsequently, the effectiveness of the test methods are experimentally verified by considering a new specimen of the Maxwell 100 F supercapacitor. The obtained results confirm that both the approaches are showing promising results, however, for different operating voltage range. This clearly indicates the need for future research towards second-life application of retired supercapacitors. Finally, the importance of choosing proper capacitance characterization scheme for reliable use of retired supercapacitors considering a wireless sensor network based realistic second-life application is discussed.

To expand the adoption of battery-operated portable consumer products and reduce the fear of running out of charge, the manufacturers and researchers have developed various health-aware fast-charging protocols. However, the different health-conscious fast charging algorithms only generates a pre-defined charging profile based on initial operating boundary conditions without having the option of real-time controls. In this work, a real-time optimal fast charging protocol is implemented by using Pontryagin’s Minimum Principle (PMP) to solve the optimal control framework having a trade-off between charging time and ohmic heat generation. Modifying the control concepts of costate jump conditions and from extensive offline optimization results, the real-time optimal fast charging protocol is examined for varying operating constraints. The effect of different boundary conditions, mainly due to charging behaviours, on the charging profile and other sensitive parameters are also investigated and compared with a standard CCCV charging algorithm. Finally, the comparison between a typical optimal fast charging profile and a standard 2C CCCV protocol is experimentally examined.

Background: Congenital heart diseases (CHD) are one of the most common developmental errors in humans.Objectives: The purpose of the present study was to see the frequencies of various types of atrial septal defect (ASD) and associated cardiovascular disorders in patients undergoing surgical repair.Methodology: This cross-sectional descriptive study was conducted on patients undergoing surgical repair at the National Institute of Cardiovascular Diseases (NICVD) and National Heart Foundation and Research Institute (NHF&RI) in Dhaka during the period of July, 2010 to June, 2011. Patients presented with ASD at any age of both sexes were selected as study population. Diagnoses were revealed with echocardiography and confirmed preoperatively by registered cardiac surgeons.Results: The morphological types of ASD were Ostium secundum type in 96% cases and sinus venosus type in 4% cases. Atrial septal defects were either small or larger defects associated with pulmonary hypertension in 38(76%) cases, varying degree of tricuspid regurgitation was seen in 33(66%) patients and dilated pulmonary artery was noted in 24(48%) cases. Ventricular septal defect in 4(8%) cases, tricuspid atresia in 2(4%) cases and mitral valve prolapse in 6(12%) cases were also observed.Conclusions: Ostium secundum type of ASD is found to be the commonest type of ASD.J Shaheed Suhrawardy Med Coll, 2015; 7(1):18-21

Background : Laparoscopic rectopexy is performed to repair the complete rectal prolapse. Objective : The aim of this study was to see the safety of laparoscopic mesh rectopexy in patients with complete rectal prolapse after doing a case series at a tertiary care hospital. Methodolog y: This was a case series carried out at Shaheed Suhrawardy Medical College Hospital, Dhaka and at a private clinic from January 2005 to December 2010 for a period of 5 years. All female patients presented with complete rectal prolapse were included in this study. Follow up and outcomes were measured after operation. Result : A total number of 6 female patients were operated due to complete rectal prolapse. The mean age (iSD) of the study population was 64.4(i4.615) years. The age range was 58 to 70 years. The mean (iSD) duration of operation was 127.oi25.150 minutes. Constipation was reported in 33.3% cases of patients and 66.7% patients were without any complications. Conclusion : Laparoscopic mesh rectopexy is a technically feasible and safety method for treatment of complete rectal prolapse. J Shaheed Suhrawardy Med Coll, 2014; 6(2):67-70

Rotating Detonation Engines (RDE) offer an alternative combustion strategy to replace conventional constant pressure combustion with a process that could produce a pressure gain without the use of a mechanical compressor. Recent numerical and experimental publications that consider air as the oxidizer have primarily focused on the ability of these annular combustors to sustain a stable continuous detonation wave when fueled by hydrogen. However, for this to be a viable consideration for the land-based power generation it is necessary to explore the ability to detonate natural gas and air within the confines of the annular geometry of an RDE. Previous studies on confined detonations have expressed the importance of permitting detonation cells to fully form within the combustor in order to achieve stability. This poses a challenge for natural gas–air fueled processes as their detonation cell size can be quite large even at moderate pressures. Despite the practical importance, only a few studies are available on natural gas detonations for air-breathing RDE applications. Moreover, the extreme thermodynamic condition (high temperature inside the combustor) allows limited accessibility inside the combustor for detailed experimental instrumentations, providing mostly single-point data. Recent experimental studies at the National Energy Technology Laboratory (NETL) have reported detonation failure at higher methane concentration in an air-breathing RDE fueled by natural gas-hydrogen fuel blends. This encourages to perform a detailed numerical investigation on the wave characteristics of detonation in a natural gas-air fueled RDE to understand the various aspects of instability associated with the natural gas-air detonation. This study is a numerical consideration of a methane-air fueled RDE with varying operating conditions to ascertain the ability to achieve a stable, continuous detonation wave. The simulations have been performed in a 2D unwrapped RDE geometry using the open-source CFD library “OpenFOAM” employing an unsteady pressure-based compressible reactive flow solver with a k–ε turbulence model in a structured rectangular grid system. Both reduced and detailed chemical kinetic models have been used to assess the effect of the chemistry on the detonation wave characteristics and the underlying flow features. A systematic grid sensitivity study has been conducted with various grid sizes to quantify the weakly stable overdriven detonation on a coarse mesh and oscillating features at fine mesh resolutions. The main focus of the current study is to investigate the effects of operating injection pressure on detonation wave characteristics of an air-breathing Rotating Detonation Engine (RDE) fueled with natural gas-hydrogen fuel blends. Wave speeds, peak pressures and temperatures, and dominant frequencies have been computed from the time histories. The flow structures were then visualized using 2D contours of temperature and species concentration.

Containers offer a broad array of benefits, including a consistent lightweight runtime environment through OS-level virtualization, as well as low overhead to maintain and scale applications with high efficiency. Moreover, containers are known to package and deploy applications consistently across varying infrastructures. Container orchestrators manage a large number of containers for microservices based cloud applications. However, the use of such service orchestration frameworks towards HPC workloads remains relatively unexplored. In this paper we study the potential use of Kubernetes on HPC infrastructure for use by the scientific community. We directly compare both its features and performance against Docker Swarm and bare metal execution of HPC applications. Herein, we detail the configurations required for Kubernetes to operate with containerized MPI applications, specifically accounting for operations such as (1) underlying device access, (2) inter-container communication across different hosts, and (3) configuration limitations. This evaluation quantifies the performance difference between representative MPI workloads running both on bare metal and containerized orchestration frameworks with Kubernetes, operating over both Ethernet and InfiniBand interconnects. Our results show that Kubernetes and Docker Swarm can achieve near bare metal performance over RDMA communication when high performance transports are enabled. Our results also show that Kubernetes presents overheads for several HPC applications over TCP/IP protocol. However, Docker Swarm's throughput is near bare metal performance for the same applications.

Supercapacitors (SC) have gained a lot of attention as energy storage and power supply option due to its several advantageous characteristics and broad applicability. Self-discharge remains one of the key issues while using supercapacitor as energy storage device, especially for low duty cycle applications. The SC terminal voltage gets affected by the self-discharge of the device under no-load condition. The self-discharge of SC depends on its charging-rate and the capacitance value. In this paper, we propose a computationally efficient empirical model for characterizing the self-discharge response of a series of supercapacitors. The empirical model takes the effect of SC charging-rate and capacitance into account. In the process, we propose a generalized model parameter identification scheme based on least-square error. Then, we demonstrate the effectiveness of the proposed model and the identification scheme by performing experimental study on a number of commercially available Maxwell HC series SCs. we conduct the experimental study for different level of charging-rate from 1C to 50C. The experimental validation is found to be satisfactory and promising.

In a multi-tenant environment, users' resource demands must be understood by cluster administrators to efficiently and fairly share cluster resources without hindering performance. Kubernetes is a container orchestration system that enables users to share cluster resources, such as CPU, memory, and disk, for the execution of their tasks. Kubernetes provides a monolithic scheduler to make scheduling decisions for all users in a multi-tenant shared cluster. Kube-batch enables Kubernetes to make a scheduling decision based on a multi-resource fairness policy called Dominant Resource Fairness (DRF). DRF has been proven to be a successful mechanism for fine-grained resource allocation. However, it does not incorporate other fairness aspects of a shared cluster. Our fairness metrics take into account the use of DRF along with a task's resource demand and average waiting time. We have developed a policy-driven meta-scheduler, KubeSphere, for a Kubernetes cluster where tasks for individual users can be scheduled based on each user's overall resource demands and current resource consumption. Our experimental results show how the dominant share of a task along with the overall resource demand can improve fairness in a multi-tenant cluster.

With the growing consensus on simple power law inflation models not being favored by the PLANCK observations, dynamics for the non-standard inflation gain significant interest in the recent past. In this paper, we analyze in detail a class of supergravity inspired phenomenological inflationary models with non-polynomial potential based on Maity (Nucl.Phys. B919 (2017) 560), and compare the model predictions with the currently most favored Starobinsky and its generalized $\alpha$-attractor models in the ($n_s$ , $r$) plane constrained by PLANCK. Importantly for a wide range of parameter space, our model provides successful inflation in the sub-Planckian regime. We also have performed model independent analysis of reheating in terms of the effective equation of state parameter. In particular, we consider two stages of reheating dynamics with generalized inflaton equation of state in the initial and relativistic equation of state in the later phase. Finally, we show how our generalized reheating analysis constrains the inflation models under consideration, Comment: 27 pages, 8 figures. Matches Published version. (This work supersedes the work: arXiv:1610.00173 [astro-ph.CO])

The popularity of supercapacitors (SC) as an energy storage device is growing along with the development of the electrical and electronics applications demanding high operating power. Consequently, the number of retired SC cells is increasing leading to the recycling problem. Supercapacitor reaches its end-of-life (EOL) when its nominal capacitance is decreased by 20% and the initial equivalent series resistance (ESR) is increased by 100%. Under this scenario, the SC is no-longer suitable for its original purpose as a source of high power. However, the aged supercapacitors often retain enough capacity to serve the applications demanding low operating power. This paper investigates the possibility to re-purpose the aged supercapacitors for low power second-life applications. Specifically, we propose a capacitance prognosis model as a function of the operating power of second-life applications. We consider three aged Maxwell supercapacitors to illustrate the proposed scheme. Subsequently, we identify their effective capacitance considering MICAz wireless sensor module as the low power second-life application. Next, we evaluate the sensitivity and robustness of the proposed model. Finally, we study the second-life aging of the aged supercapacitors under low-power charge–discharge cycling.

The present study discusses the results pertaining to eduction of coherent structures and assesses their contribution in promoting mixing between low and high momentum fluid streams to enhance thermal convection. The analysis has been carried out numerically in a periodic parallel-plate-channel containing built-in longitudinal vortex generators on the bottom wall. The Reynolds number of the investigation is 6000 based on the channel height and bulk mean velocity. The computational geometry resembles heat exchanger surfaces on which the vortex generators create strong longitudinal vortices that enhance heat transfer on the plane channel wall. At high Reynolds numbers, the enhancement of convective heat transfer near the wall largely depends on the large scale turbulent structures (coherent structures) that disappear and reappear frequently and exhibit typical correlated scales in time or space. Proper orthogonal decomposition (POD) is an efficient tool to identify these coherent turbulent structures from instantaneous flow field data. Despite geometrical simplicity, the complex swirling motion behind the vortex generators demands highly accurate computational method, like the large eddy simulation (LES) of turbulence for capturing the nuances of flow. The instantaneous velocity data at a cross-flow plane have been assembled over a long time-window and analyzed deploying POD technique to extract the large- and small-scale structures based on the turbulent kinetic energy of the structures. Reconstructions of the velocity field using different combinations of eigenmodes have yielded different patterns of the flow. Large-scale structures have been visualized using first few energetic modes, while remaining less energetic modes have provided small-scale structures. The technique enables us to identify coherent structures hidden in the random flow field by filtering the small scale effects. The analysis yields as large as 15 dominant POD modes to cumulatively capture as low as 25% of the total turbulent kinetic energy of the flow, indicating broad range of energy spectrum that shares a large number of POD modes and thereby concludes highly complex turbulent fields with numerous spatial and temporal turbulent scales. Reconstructed velocity fields considering the leading dominant modes reveal a cut-off of 43% turbulent kinetic energy to clearly expose the coherent structures, which are consistent with published literature on similar turbulent channel flows. Additionally, quadrant analysis on the reconstructed velocity fields has clearly revealed that sweep and ejection modes are the only dominating Reynolds-stress-producing events for the current flow of interest, where the vortices lift the low-momentum fluid away from wall through the ejection mechanism. The high-momentum fluid impinges on the wall in sweep mode.

Background: Atrial septal defect (ASD) is one of the important congenital anomaly. Objective: The present study is designed to determine how the different morphological types of ASD are distributed among Bangladeshi Bengali patients undergoing surgical repair and to see the clinical features of the above patients. Methodology: This cross-sectional descriptive study was carried out on the 50 ASD patients undergoing surgical repair at the National Institute of Cardiovascular Diseases (NICVD) or the National Heart Foundation and Research Institute (NHF & RI) in Dhaka, during the period of July 2010 to June 2011 to explore different morphological types and clinical presentation. The morphological types of ASD were revealed by echocardiography and confirmed preoperatively. Result: A total number of 50 patients were recruited in this study of which ostium secundum type was found in 96% cases and sinus venosus type in 4% cases. Evaluation of patients showed that 14% of the patients were asymptomatic and they were detected incidentally. The most common symptoms were palpitation, dyspnea, recurrent RTI, fatigue, failure to thrive and chest pain. The commonest signs at diagnosis included loud S1, wide and fixed splitting S2, systolic murmur, tachycardia, shifting of the apex beat and left parasternal lift. Surgical closure has been the mainstream of treatment. Conclusion: In conclusion ostium secundum is the most common type of ASD.

Background: Laparoscopic cholecystectomy (LC) is one of the most common general surgical procedure. Objective: The purpose of the present study was to observe the surgical outcomes of the patients after clipless laparoscopic cholecystectomy. Methodology: This case series were performed in the Department of Surgery at Shaheed Suhrawardy Medical College & Hospital, Dhaka from June 2014 to April 2015. After several modifications, the success of intracorporeal “separate knotting of cystic artery and duct” was observed with Vicryl and was successfully used separate ligation of cystic artery and duct (SLAD) with Vicryl 1/0 in symptomatic cholelithiasis patients. Result: A total number of 50 cases were undergone elective laparoscopic cholecystectomy. Most of the patients were female (80.0%). Average age of patients was 39 yr (15-65). There was no bile leak or other complications related to ligature. The time taken for tie varied from 2 to 4 minutes (average 3 min). There were 10(25.0%) acute calculus cholecystitis, including empyema, gangrenous cholecystitis. No patient had port infection. Conclusion: Clipless LC is a safe and effective method.Journal of Science Foundation, 2015;13(1):11-14DOI: http://dx.doi.org/10.3329/jsf.v13i1.27828

The mixed convective flow and heat transfer of nanofluids past a rotating cylinder placed in a uniform cross stream is investigated via SUPG (streamline upwind Petrov–Galerkin) based finite element method. Nano sized copper (Cu) particles suspended in water are used with Prandtl number ( Pr ) = 6.9. The computations are carried out at a representative Reynolds number ( Re ) of 100. The dimensionless cylinder rotation rate ( α ) is varied between 0 and 2. The range of nanoparticle volume fractions ( ϕ ) considered is 0 ≤ ϕ ≤ 5%. Effect of aiding buoyancy is brought about by considering two fixed values of the Richardson number ( Ri ) as 0.5 and 1.0. The thermophysical properties of nanofluid is predicted using a model which considers the fundamentals of interparticle interaction kinetics according to the details of agglomeration–deagglomeration of nanoparticles, variations in the effective particulate dimensions and agglomerate size ( n ), as well as the volume fractions of the particulate system. Increase in cylinder rotation and nanoparticle agglomeration shows suppression of vortex shedding. Completely steady solution is obtained at α = 2 . At Ri = 0.5, ϕ = 5 % , and n = 5, vortex shedding disappears and the flow achieves a steady state. A von Karman street is seen at α = 1.5 , for n > 1 and ϕ ≤ 3%. For ϕ = 4 % and 5%, vortex shedding ceases at n = 5. Characterisation of vortex shedding by POD (proper orthogonal decomposition) shows that increase in the values of n institutes coherence in the wake vortical structures. The average Nusselt number decreases with increasing α and increases with increasing n . At n = 5, a significant enhancement in heat transfer is seen.

Apache Mesos, a two-level resource scheduler, provides resource sharing across multiple users in a multi-tenant clustered environment. Computational resources (i.e., CPU, memory, disk, etc.) are distributed according to the Dominant Resource Fairness (DRF) policy. Mesos frameworks (users) receive resources based on their current usage and are responsible for scheduling their tasks within the allocation. We have observed that multiple frameworks can cause fairness imbalance in a multi-user environment. For example, a greedy framework consuming more than its fair share of resources can deny resource fairness to others. The user with the least Dominant Share is considered first by the DRF module to get its resource allocation. However, the default DRF implementation, in Apache Mesos' Master allocation module, does not consider the overall resource demands of the tasks in the queue for each user/framework. This lack of awareness can lead to poor performance as users without any pending task may receive more resource offers, and users with a queue of pending tasks can starve due to their high dominant shares. In a multi-tenant environment, the characteristics of frameworks and workloads must be understood by cluster managers to be able to define fairness based on not only resource share but also resource demand and queue wait time. We have developed a policy driven queue manager, Tromino, for an Apache Mesos cluster where tasks for individual frameworks can be scheduled based on each framework's overall resource demands and current resource consumption. Dominant Share and demand awareness of Tromino and scheduling based on these attributes can reduce (1) the impact of unfairness due to a framework specific configuration, and (2) unfair waiting time due to higher resource demand in a pending task queue. In the best case, Tromino can significantly reduce the average waiting time of a framework by using the proposed Demand-DRF aware policy.

Understanding the properties of dark matter has proved to be one of the most challenging problems of particle phenomenology. In this paper, we have tried to understand the phenomenology of dark matter in light of very well understood properties of cosmic microwave background (CMB) anisotropy. To connect these two, inflation and its subsequent evolution known as the reheating phase play the important role. Following the previous analysis, we first established a one-to-one correspondence between the CMB power spectrum and the reheating temperature assuming the perturbative reheating scenario. Further by incorporating a possible dark matter candidate through the radiation annihilation process during reheating and the current value of dark matter abundance, we constrain the dark matter parameter space through the inflationary power spectrum for different inflationary models., Added discussions, matches published version

We consider the CMB constraints on reheating and dark matter parameter space for a specific plateau type inflationary model. The plateau inflationary models which are currently most favored models from data can be well approximated by a potential of the form $V(\phi)\propto \phi^n$ around $\phi=0$. This fact makes it possible to study the reheating phase with general inflaton equation of state in a viable cosmological scenario. In addition, following our recent work[1], we generalize the connection between reheating and the present CMB data and the dark matter parameter space for general inflaton equation of state parameter., Comment: Some bounds and results improved, Matches published version

With the Planck 2015 result, most of the well known canonical large field inflation models turned out to be strongly disfavored. Axion inflation is one of such models which is becoming marginalized with the increasing precession of CMB data. In this paper, we have shown that with a simple Galileon type modification to the marginally favored axion model calling G-axion, we can turn them into one of the most favored models with its detectable prediction of $r$ and $n_s$ within its PLANCK $1\sigma $ range for a wide range of parameters. Interestingly it is this modification which plays the important role in turning the inflationary predictions to be independent of the explicit value of axion decay constant $f$. However, dynamics after the inflation turned out to have a non-trivial dependence on $f$. For each G-axion model there exists a critical value of $f_c$ such that for $f>f_c$ we have the oscillating phase after inflation and for $f, Comment: Added discussion on stability, matches published version

Selfdischarge characteristics of supercapacitors play a significant role in their sizing and power management. Furthermore, supercapacitor-s' selfdischarge, defined as no load voltage drop, is directly proportional to its charging rate. The paper proposes a framework to empirically model the terminal voltage response of supercapacitors during charge and selfdischarge. A set of empirical formulae has been identified by utilizing experimental data and nonlinear optimization technique for modelling, the charge and selfdischarge responses of supercapacitors. The empirical models are functions of charging rate and time. The proposed approach has been illustrated via experimental studies on a 10F commercial supercapacitor cell. The illustration shows a good agreement between the model responses and experimental data.

The objective of the present investigation is to assess the performance of a plate-fin heat exchanger with an emphasis on acquiring fundamental understanding of the relation between local flow behavior and heat transfer augmentation mechanism. Numerical simulations are performed in a rectangular channel containing built-in longitudinal vortex generators on the bottom wall arranged periodically both in the streamwise and spanwise directions. Two types of vortex generators, namely, rectangular winglet pair (RWP) and delta-winglet pair (DWP) with two different flow arrangements, common-flow-up (CFU) and common-flow-down (CFD) have been explored to assess the influence of shape and flow arrangements on heat transfer enhancement. The basic mechanisms of flow structure and heat transfer characteristics have been examined with the help of secondary velocity vectors, streamlines, and temperature contours. Additionally, the mechanism of the local heat transfer augmentation has been explained using a novel concept called the field synergy principle. The performance of the vortex generators has been compared based on integral quantities such as Nusselt number, pressure loss, performance evaluation factor and domain averaged synergy angle. The computations reveal enhanced mixing of fluid between the wall layer and the core due to strong secondary flows produced by vortex generators. The performance analysis indicates that the RWP is more effective in terms of heat transfer enhancement as compared to DWP. The field synergy analysis has shown that the sites with higher Nusselt number are associated with smaller synergy angle or better coordination between the velocity vector and the temperature gradient.

Accurate information of supercapacitor (SC), also called electric double layer capacitor, leakage current is vital for effective State-of-Charge (SOC) estimation in Wireless Sensor Network (WSN) applications having long rest phase. In addition to improving accuracy of SOC estimation, real-time information on leakage current is highly beneficial for SC health monitoring. On the other hand, accurate mapping of SC open circuit voltage (OCV) vs. SOC significantly contributes towards accurate SOC estimation. Inaccuracies in either of these two information, i.e. leakage and OCV-SOC map, lead to inaccuracies in estimated SOC. In this paper, we propose a real-time estimation framework for accurate estimation of SOC under uncertain leakage and OCV-SOC map. Specifically, the proposed approach co-estimates leakage and part of OCV-SOC map in real-time along with SOC. The estimation framework utilizes Unscented Kalman Filter (UKF) along with an Equivalent Circuit Model (ECM) which captures SC leakage phenomenon. We identify the ECM parameters based on a Maxwell 25 F commercial SC. The experimentally identified ECM is subsequently used to perform simulation and experimental studies to validate the proposed framework. Finally, the robustness of the proposed framework with respect to parametric and measurement uncertainties is verified.