Modeling of wind energy conversion system using PSCAD/EMTDC

This paper aims to model a complete wind energy conversion system (WECS) connected to a grid. The motivation comes from the Distributed Generation System (DGS) installed at the Renewable Energy Lab at UMass Lowell. The objective of this work is to develop universal and standardized manufacturer independent textbook models. Manufacturer specific models are more accurate and detailed, but proprietary and non-disclosure agreements become an issue for research purposes. Since the wind turbines installed in the lab are VSWT (Variable Speed Wind Turbine) with Permanent Magnet Synchronous Generators (PMSG), so such a turbine system is modeled to represent them in general. PMSG requires very less maintenance and has high efficiency since it doesn't have rotor current and is used without a gearbox. Further, there are two more advantages: first, it has the capability of variable speed control due to the fact that its rotor speed can change in a large range; second, it's excitation system is independent of the grid and require any other excitation source. In addition to the turbine generator, other main components of WECS are also modeled namely: wind source model, wind turbine, permanent magnet synchronous generator and AC/DC/AC control. The equations governing these models are also discussed. The entire generation system is implemented on PSCAD/EMTDC and integrated to a grid and a basic fault analysis is done under different conditions. The proposed model can be used for research purposes on distributed generation issues. This model provides a good software simulation test bed for further research

Investigation of hydraulic imbalance for converting existing boiler based buildings to low temperature district heating

The hydraulic balance of heating network is considered as a pre-condition for the implementation of low temperature district heating (LTDH). Its imbalance result into high energy consumption and heat-losses in the network. In this study, a novel hydraulic model is presented which investigates hydraulic imbalance in the LTDH network, using real weather and hourly monitored operational heating data from an existing boiler based building. Analysis of delta t in space-heating system shows that the delta t is maximum when the outside air temperature is lowest and it decreases with increase in outside air temperature. Furthermore, the hydraulic imbalance is analysed for four different control scenarios with the aim to find an optimum scenario with minimum pumping power, energy consumption and heat-losses in the LTDH network. Results show that the hydraulic imbalance is due to the absence of flow-limiters and balancing valves on the return pipe and thermostatic radiator valves (TRVs) alone are unable to maintain hydraulic balance in the space-heating system of buildings. Moreover, the control scenario with variable flow-rate and fixed supply water temperature from the sub-station is found to be optimum. Compared to the constant flow-rate scenario, the pumping power, energy consumption and heat-losses in the LTDH network are reduced by approximately 2%, 63% and 14%, respectively

Ganglioneuroblastoma of the posterior mediastinum: a case report.

Introduction:Ganglioneuroblastoma is a rare peripheral neuroblastic tumor that is derived from developing neuronal cells of the sympathetic nervous system, and is found mostly, but not exclusively, in babies and young children. Case Presentation: To the best of our knowledge, there have been no previously reported cases of ganglioneuroblastoma of the mediastinum from Pakistan. We present a case of ganglioneuroblastoma in an eight-year-old Pakistani Sindhi boy incidentally found to have a large posterior mediastinal mass that on biopsy initially looked like ganglioneuroma. He underwent successful excision of the mediastinal mass and remained stable post-operatively. Final pathology findings showed a ganglioneuroblastoma. He has remained free of symptoms on long-term follow-up. Conclusions: The rarity of this tumor along with its almost exclusive occurrence in the pediatric population necessitates a thorough investigation of Patients presenting with a symptomatic mass

Organic dye adsorption on activated carbon derived from solid waste

Activated carbon was prepared through a chemical activation of bamboo waste precursor (BMAC) using phosphoric acid as the activating agent at 500°C for 2 h. Batch adsorption studies were carried out for the adsorption of C.I. Reactive Black 5 (RB5) onto the BMAC. The effect of various experimental parameters such as initial dye concentration (50–500 mg/L), contact time (0–32 h), pH (2–12), and temperature (30–50°C) were investigated. Equilibrium data were found to be very well represented by the Freundlich isotherm and a pseudo-second-order model was found to explain the kinetics of RB5 adsorption more effectively. The mechanism of the adsorption process was determined by the intraparticle diffusion model. Thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°), standard free energy (ΔG°), and activation energy were determined. The results indicated that BMAC is a suitable adsorbent material for adsorption of reactive dye from aqueous solutions

Karo Kari : the murder of honour in Sindh Pakistan : an ethnographic study

This paper aims to discuss the wider context, in which honour murders occur, the social structures which contribute to the occurrence and perpetuation of the practice of honour murders. An ethnographic fieldwork was conducted in Jacobabad Sindh, Pakistan. The study found that honour murders were not solely driven by customs and traditions, but also by a feudal culture, male-dominated social structures, the complicit role of state institutions and law enforcement agencies and a web of vested interests. Therefore, honour murders may be prevented by reducing the influence and interference of feudal lords on state institutions, in particular law enforcement agencies, and by promoting education that challenges a patriarchal and feudal mind-set in the community

Nutritional status in patients with Hepatitis C

OBJECTIVE: To assess the nutritional status via the SGA (subjective global assessment) screening tool of patients at all stages of hepatitis C virus (HCV) liver disease. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Out-patient Clinics of the Aga Khan University Hospital, Karachi, conducted from October 2009 to January 2011. METHODOLOGY: Patients with hepatitis C virus infection and their HCV-negative attendants were enrolled from the outpatient clinics, and categorized into 4 groups of 100 patients each: healthy controls (HC), those with chronic hepatitis C infection (CHC), compensated cirrhotics (CC) and decompensated cirrhotics (DC). The validated subjective global assessment (SGA) tool was used to assess nutritional status. RESULTS: A total of 400 patients were enrolled. Most of the patients in the HC group were class \u27A\u27 (best nutritional status). In contrast, the majority (64%) in the DC group were in the class \u27C\u27 (worst status). The compensated cirrhosis (CC) group showed that 90% of patients were malnourished, while 98% of all patients were malnourished in the DC group, predominantly class \u27C\u27. Most importantly, 14% of patients with chronic hepatitis C (CHC) also scored a \u27B\u27 on the SGA; which when compared to HC was statistically significant (p=0.005). As the groups progressed in their disease from CHC to DC, the transition in nutritional status from \u27A\u27 to \u27C\u27 between groups was statistically significant. CONCLUSION: Malnutrition occurs early in the course of HCV, and progresses relentlessly throughout the spectrum of HCVdisease

Cystathione gamma lyase/hydrogen sulphide pathway up regulation enhances the responsiveness of ?1A and ?1B-adrenoreceptors in the kidney of rats with left ventricular hypertrophy

The purpose of the present study was to investigate the interaction between H2S and NO (nitric oxide) in the kidney and to evaluate its impact on the functional contribution of ?1A and ?1B-adrenoreceptors subtypes mediating the renal vasoconstriction in the kidney of rats with left ventricular hypertrophy (LVH). In rats the LVH induction was by isoprenaline administration and caffeine in the drinking water together with intraperitoneal administration of H2S. The responsiveness of ?1A and ?1B to exogenous noradrenaline, phenylephrine and methoxaminein the absence and presence of 5-methylurapidil (5-MeU) and chloroethylclonidine (CEC) was studied. Cystathione gamma lyase (CSE), cystathione ? synthase (CBS), 3-mercaptopyruvate sulphar transferase (3-MST) and endothelial nitric oxide synthase (eNOS) were quantified. There was significant up regulation of CSE and eNOS in the LVH-H2S compared to the LVH group (P<0.05). Baseline renal cortical blood perfusion (RCBP) was increased (P<0.05) in the LVH-H2S compared to the LVH group. The responsiveness of ?1A-adrenergic receptors to adrenergic agonists was increased (P<0.05) after administration of low dose 5-Methylurapidil in the LVH-H2S group while ?1B-adrenergic receptors responsiveness to adrenergic agonists were increased (P<0.05) by both low and high dose chloroethylclonidine in the LVH-H2S group. Treatment of LVH with H2S resulted in up-regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways in the kidney. These up regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways enhanced the responsiveness of ?1A and ?1B-adrenoreceptors subtypes to adrenergic agonists in LVH-H2S. These findings indicate an important role for H2S in modulating deranged signalling in the renal vasculature resulting from LVH development

Access to person-centered care: a perspective on status, barriers, opportunities and challenges from the Eastern Mediterranean Region

Background: Access to Person-Centered care is a major area of concern throughout the world including the Eastern Mediterranean Region. Objective: This networking paper reviews current status, barriers, opportunities, challenges and future directions with regards to Access to Person-Centered care in the Eastern Mediterranean Region. Methods: The lead Author from the Working Party on Research of Eastern Mediterranean Region invited members through its ya-hoo group to participate in this networking project. Objectives and work plan were developed by the lead Author and shared with interested contributors. Co-Authors and Advisors were invited to contribute and timelines were set for contributors to submit their report. Submissions were collected by lead authors and put into a draft that was shared with contributors for feedback. After incorporating feedback, the final draft was edited by the Editor before submission for publication consideration. Results: Access to Person-Centered care in the Eastern Mediterranean Region shows extreme variations. At one end there are oil and gas rich countries that offer advanced health care services to the majority of their local population while on the other end are impoverished countries that are unable to provide even minimum required services to their people. Inequalities in health status have been growing since the mid-1990s and have resulted in an increasing gap between the most advantaged and disadvantaged social groups. There are social, cultural, religious and economical barriers that may impede access to healthcare. It warrants a need to address these barriers on a priority basis so that Universal access to Person-Centered care may be made available to the population of the region. Conclusion: A well planned and evidence based approach is the only way forward to ensure universal access to all populations in the Eastern Mediterranean Region. Access to Person-Centered care is the need of the hour in the region. Provision of health care services through a well deined health system with a prime focus on a primary care model delivered by trained family doctors is the single most appropriate step to achieve health for all

Improving the Quality of Healthcare Using Big Data

In India there is a lack of doctorrsquos availability in rural areas compare to urban areas because of which the number of deaths is increasing in the rural areas. To solve this issue we are building an android application (Healtho) which will recommend the disease based on the symptoms given by the end user. Basically, a recommended system will be used by using Hadoop with mahout that is a Big Data concept. By using android as a platform we can provide higher availability of the system to the end user and provide some emergency services like location of nearby Hospitals and blood bank. The system also provides the medicine time (Meditime) in which the end user may come to know at what time the medicine is to be taken. This system could mostly be used by the people who live in rural area because there is lack of doctorrsquos availability and hospitals.nbs