149 research outputs found
Cost–benefit analysis of a virtual power plant including solar PV, flow battery, heat pump, and demand management: A Western Australian case study
Achieving the renewable energy integration target will require the extensive engagement of consumers and the private sector in investment and operation of renewable-based energy systems. Virtual power plants are an efficient way to implement this engagement. In this paper, the detailed costs and benefits of implementing a realistic virtual power plant (VPP) in Western Australia, comprising 67 dwellings, are calculated. The VPP is designed to integrate and coordinate rooftop solar photovoltaic panels (PV), vanadium redox flow batteries (VRFB), heat pump hot water systems (HWSs), and demand management mechanisms. An 810-kW rooftop solar PV system is designed and located using the HelioScope software. The charging and the discharging of a 700-kWh VRFB are scheduled for everyday use over a year using an optimization algorithm, to maximize the benefit of it for the VPP owners and for the residents. The use of heat pump HWSs provides a unique opportunity for the residents to save energy and reduce the total cost of electricity along with demand management on some appliances. The cost-and-benefit analysis shows that the cost of energy will be reduced by 24% per dwelling in the context of the VPP. Moreover, the internal rate of return for the VPP owner is at least 11% with a payback period of about 8.5 years, which is a promising financial outcome
Optimal sizing design and operation of electrical and thermal energy storage systems in smart buildings
Photovoltaic (PV) systems in residential buildings require energy storage to enhance their productivity; however, in present technology, battery storage systems (BSSs) are not the most cost-effective solutions. Comparatively, thermal storage systems (TSSs) can provide opportunities to enhance PV self-consumption while reducing life cycle costs. This paper proposes a new framework for optimal sizing design and real-time operation of energy storage systems in a residential building equipped with a PV system, heat pump (HP), thermal and electrical energy storage systems. For simultaneous optimal sizing of BSS and TSS, a particle swarm optimization (PSO) algorithm is applied to minimize daily electricity and life cycle costs of the smart building. A model predictive controller is then developed to manage energy flow of storage systems to minimize electricity costs for end-users. The main objective of the controller is to optimally control HP operation and battery charge/discharge actions based on a demand response program. The controller regulates the flow of water in the storage tank to meet designated thermal energy requirements by controlling HP operation. Furthermore, the power flow of battery is controlled to supply all loads during peak-load hours to minimize electricity costs. The results of this paper demonstrate to rooftop PV system owners that investment in combined TSS and BSS can be more profitable as this system can minimize life cycle costs. The proposed methods for optimal sizing and operation of electrical and thermal storage system can reduce the annual electricity cost by more than 80% with over 42% reduction in the life cycle cost. Simulation and experimental results are presented to validate the effectiveness of the proposed framework and controller
Constitutive modeling of multi-stimuli-responsive shape memory polymers with multi-functional capabilities
Nowadays, shape memory polymers (SMPs)-based devices are required to be much smarter to produce large shape memory recovery and recovery force with lower working temperatures. They could play a vital role in the advancement of soft robot manipulators, biomedical tools and wearable devices where the working temperatures is a key challenge and must be around the body temperature, or in sustainable smart systems with low energy consumption. The aim of this paper is to introduce thermo-electro-magneto-responsive fibrous SMPs (TEMFSMPs) as a new class of SMPs with highly enhanced shape recovery and recovery force and reduced working temperature. A three-dimensional constitutive model is developed to simulate thermo-electro-magneto-visco-hyperelastic behaviors of SMPs under large deformation for the first time. Constitutive relations are derived by adopting an electro-magneto-visco-hyperelasticity theory and implementing it in a thermo-mechanical cycle of SMPs. To improve the strength of thermo-electro-magneto-responsive SMPs, a bunch of fibers is also embedded into the SMP matrix. Then, the proposed model for thermo-electro-magneto-responsive fibrous shape memory polymers (TEMFSMPs) under uniaxial tension and complex loading regimes such as simultaneous torsion and extension are solved semi-analytically. In addition, the thermo-mechanical response through the proposed model is validated via available SMP experimental tests. Numerical results reveal that electro-magnetic features can significantly enhance shape memory recovery and recovery force of TEMFSMPs and lower their working temperatures. It is found that the electro-magnetic field, the orientation, and stiffness of fibers can effectively be set to tune the shape memory effect and bio-applicability of TEMFSMPs with highly enhanced stress/strain recovery and reduced working temperature
Caon serum iron level, ferritin and total iron binding capacity level among nonpregnant women with and without melasma
Background: Melasma is a common acquired disorder characterized by symmetric, hyperpigmented patches with an irregular outline, occurring most commonly on the face. It is most prevalent among young to middle-aged women. Although iron overload affects skin pigmentation, effect of iron deficiency on skin is not clear. So, we evaluated serum iron level, ferritin and total iron binding capacity (TIBC) level among nonpregnant women with and without melasma. Materials and Methods: A cross-sectional case study was conducted in 2012 at university dermatologic department on 33 nonpregnant women with melasma (case) and 33 nonpregnant women without melasma (control). Serum iron level, TIBC and ferritin in the two groups was measured and compared. Results: Serum iron level was lower in the case group (85 ± 11) in comparison with control group (102 ± 9), but the difference was not significant (P: 0.9). Mean TIBC and Ferritin were higher in the case group (TIBC: 329.4 ± 29, ferritin: 6 ± 18) than the control group (TIBC: 329.3 ± 29, ferritin: 33 ± 6) without significant difference. Conclusion: Although the serum iron level was lower in nonpregnant women with mealsma, it was not significant compared with those without melasma. © 2015, Isfahan University of Medical Sciences(IUMS). All rights reserved
Importance of Magnesium Status in COVID-19
A large amount of published research points to the interesting concept (hypothesis) that magnesium (Mg) status may have relevance for the outcome of COVID-19 and that Mg could be protective during the COVID disease course. As an essential element, Mg plays basic biochemical, cellular, and physiological roles required for cardiovascular, immunological, respiratory, and neurological functions. Both low serum and dietary Mg have been associated with the severity of COVID-19 outcomes, including mortality; both are also associated with COVID-19 risk factors such as older age, obesity, type 2 diabetes, kidney disease, cardiovascular disease, hypertension, and asthma. In addition, populations with high rates of COVID-19 mortality and hospitalization tend to consume diets high in modern processed foods, which are generally low in Mg. In this review, we review the research to describe and consider the possible impact of Mg and Mg status on COVID-19 showing that (1) serum Mg between 2.19 and 2.26 mg/dL and dietary Mg intakes > 329 mg/day could be protective during the disease course and (2) inhaled Mg may improve oxygenation of hypoxic COVID-19 patients. In spite of such promise, oral Mg for COVID-19 has thus far been studied only in combination with other nutrients. Mg deficiency is involved in the occurrence and aggravation of neuropsychiatric complications of COVID-19, including memory loss, cognition, loss of taste and smell, ataxia, confusion, dizziness, and headache. Potential of zinc and/or Mg as useful for increasing drug therapy effectiveness or reducing adverse effect of anti-COVID-19 drugs is reviewed. Oral Mg trials of patients with COVID-19 are warranted
Epidemiology of West Nile Virus in the Eastern Mediterranean region: A systematic review
Background: West Nile Virus (WNV), a member of the genus Flavivirus, is one of the most widely distributed arboviruses in the world. Despite some evidence for circulation of WNV in countries summarized by the World Health Organization as the Eastern Mediterrian Region Office (EMRO), comprehensive knowledge about its epidemiology remains largely unknown. This study aims to provide a concise review of the published literature on WNV infections in the Eastern Mediterranean regional office of WHO (EMRO). Methodology/principal findings: A systematic review of WNV prevalence studies on humans, animals and vectors in the EMRO region was performed by searching: Web of Science, Science Direct, Scopus, PubMed, Embase and Google Scholar. Finally, 77 citations were included, comprising 35 seroprevalence studies on general population (24460 individuals), 15 prevalence studies among patients (3439 individuals), 22 seroprevalence studies among animals (10309 animals), and 9 studies on vectors (184242 vector species). Of the 22 countries in this region, five had no data on WNV infection among different populations. These countries include Kuwait, Bahrain, Oman, Syria and Somalia. On the other hand, among countries with available data, WNV-specific antibodies were detected in the general population of all investigated countries including Djibouti (0.3-60), Egypt (1-61), Iran (0-30), Iraq (11.6-15.1), Jordan (8), Lebanon (0.5-1), Libya (2.3), Morocco (0-18.8), Pakistan (0.6-65.0), Sudan (2.2-47), and Tunisia (4.3-31.1). WNV RNA were also detected in patient populations of Iran (1.2), Pakistan (33.3), and Tunisia (5.3 -15.9). WNV-specific antibodies were also detected in a wide range of animal species. The highest seropositivity rate was observed among equids (100 in Morocco) and dogs (96 in Morocco). The highest seroprevalence among birds was seen in Tunisia (23). In addition, WNV infection was detected in mosquitoes (Culex, and Aedes) and ticks (Argas reflexus hermanni). The primary vector of WNV (Culex pipiens s.l.) was detected in Djibouti, Egypt, Iran and Tunisia, and in mosquitoes of all these countries, WNV was demonstrated. Conclusions: This first systematic regional assessment of WNV prevalence provides evidence to support the circulation of WNV in the EMRO region as nearly all studies showed evidence of WNV infection in human as well as animal/vector populations. These findings highlight the need for continued prevention and control strategies and the collection of epidemiologic data for WNV epidemic status, especially in countries that lack reliable surveillance systems. © 2019 Eybpoosh et al
Educational sessions in pharmacovigilance: What do the doctors think?
Background: The aim of this study was to determine physicians"opinion regarding pharmacovigilance feedback sessions. A survey was conducted in a teaching hospital, and the physicians who attended the sessions were invited to participate by filling out a structured questionnaire. All sessions included a review of adverse drug reactions identified at the hospital and information on pharmacovigilance issues (news on warnings released by regulatory agencies or drug toxicity problems identified by recently published studies in medical journals). The survey questions were related to the interest, satisfaction, and belief in the utility of the sessions. A Likert scale (0-10 points) was used to assess physicians" opinions. Findings: A total of 159 physicians attended the sessions and 115 (72.3%) participated in the survey. The mean (SD) age was 38.9 (12.1) years, and 72 (62.6%) were men. The mean (SD) scores of interest, satisfaction with the information provided, and belief in the utility of these sessions were 7.52 (1.61), 7.58 (1.46), and 8.05 (1.38) respectively. Significant differences were observed among physicians according to medical category and speciality in terms of interest, satisfaction, and belief in the utility of those sessions. Conclusions: Educational activities for physicians, such as feedback sessions, can be integrated into the pharmacovigilance activities. Doctors who attend the sessions are interested in and satisfied with the information provided and consider the sessions to be useful. Additional studies on the development and effectiveness of educational activities in pharmacovigilance are necessary
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