Resonance Damping of LCL Filters Using Capacitor-Current Proportional-Integral Positive Feedback Method for Grid-Integrated Fuel Cell System

Nowadays, the use of grid-integrated inverter proton exchange membrane fuel cell (PEMFC) systems is becoming more prevalent due to their efficiency and favorable environmental effects. Switching the grid-connected inverters causes high-frequency harmonics, which are eliminated using LCL filters. These filters are susceptible to instability when their resonant frequency is affected by changes in network impedance. Active damping methods are used to weaken the resonance of LCL filters. However, the grid-connected inverter is prone to be unstable under grid impedance variations due to the negative equivalent resistance resulting by digital control delays. As a solution to this problem, the capacitor-current proportional-integral (PI) positive feedback active damping approach is suggested in this study. It can provide a positive equivalent resistance almost within the Nyquist frequency, i.e., the entire controllable frequency range. As a result of the proposed method, the grid-connected inverter achieves strong stability against grid impedance variations. In this study, a PEMFC stack is used to produce and inject power into the weak grid using the proposed controller. MATLAB/Simulink simulation results are presented to verify the validity of the proposed method. The simulation results show that the proposed method is stable against changes in grid impedance and PEMFC parameters, and provides a good performance

Immunogenicity of 23-Valent Pneumococcal Vaccine in Children with Systemic Lupus Erythematosus

ABSTRACT Background: Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease which is characterized by B-cell abnormality and auto-antibody generation. Since bacterial infections are the most important causes of mortality in these patients, pneumococcal vaccination is recommended for children with SLE. Objective: To investigate humoral immunity and specific-antibody formation in response to a 23-valent polysaccharide pneumococcal vaccination in SLE children and asthmatic control group. Method: The case and control groups consisted of 30 children with the mean age of 13 years who were matched by sex and age. Anti-pneumococcal antibody titers were determined using Enzyme-Linked Immunosorbent Assay (ELISA) before the vaccination with the 23-valent pneumococcal vaccine and 3 weeks later in both groups. Also the correlation between anti-pneumococcal antibody titer and different factors including age, sex, lupus activity, disease duration, medications, history of recurrent infections, and laboratory data were investigated. Results: Both groups showed significant increases in anti-pneumococcal antibody level after vaccination (p≤0.001). The increase in antibody level were almost the same in both groups (p≥0.05) such that 77.7% of SLE children and 86.2% of control children showed at least 2-fold increase in anti-pneumococcal antibody titer following immunization. Significant correlations were seen between the level of post-immunization anti-pneumococcal antibody with the age of children with SLE (p=0.02) and their age of disease onset (p=0.02). Conclusion: It is concluded that pneumococcal vaccination is generally immunogenic in children with SLE. However, a small group of patients show impaired response to the vaccine

A comparative study on the meaning in life of patients with cancer and their family members

Introduction: Overwhelming effects of cancer could be catastrophic for the patients and their family members putting them at risk of experiencing uncertainty, loss, and interruption in life. Also, it can influence their sense of meaning, a fundamental need equated with purpose in life. Accordingly, this study aimed to compare the meaning in life (MiL) of patients with cancer with and their family members. Methods: This descriptive comparative study was conducted on 400 patients with cancer and their family members admitted to university hospitals in Tabriz and Ardebil provinces, Iran. The participants were sampled conveniently and the Life Evaluation Questionnaire (LEQ) were used for collecting data which analyzed through descriptive and inferential statistics. Results: The mean score for the MiL of patients with cancer and their family members was 119 ± 16.92 and 146.2 ± 17.07, respectively. There is a significant difference between patients with cancer and their family members in terms of MiL (p<0.001). Conclusion: The MiL of patients with cancer is lower than their family members which indicates the necessity for further attention to the psychological process and its modification in Iranian healthcare systems

Survey of spiders (Arachnida: Araneae) in southwestern Iran, with new records

Twenty-nine locations in Kohgiluyeh & Boyer-Ahmad Province in southwestern Iran were sampled for spiders (Araneae) in 2016–17 using different sampling methods (hand collection, pitfall traps, and aspirators). A total of 196 identifiable specimens were collected which represented 49 species belonging to 38 genera and 15 families. Six species, namely Cheiracanthium elegans Thorell, 1875 (Cheiracanthiidae), Cryptodrassus helvolus (O. Pickard-Cambridge, 1872) (Gnaphosidae), Enoplognatha macrochelis Levy & Amitai, 1981 (Theridiidae), Xysticus xerodermus Strand, 1913 (Thomisidae), Zelotes babunaensis (Drensky, 1929) and Z. potanini Schenkel, 1963 (both Gnaphosidae) had not been previously reported from Iran. Also, an additional number of 35 species represent new records for the province.</p

Evaluating the outcomes of femoral artery ligature among the trauma induced infectious psudoaneurysm in Alzahra-Isfahan hospital during 2006-7

Background: Pseudoaneurysm is a relatively common vascular disease which may occur despite the technological advances and excessive use of femoral artery catheterization (therapeutic and diagnostic). The aim of this study was to determine the therapeutic complications and consequences of femoral artery legation compared to other procedures applied for trauma-induced infectious pseudoaneurysms.Materials and Methods: Through a cross-sectional study, all patients with infectious femoral artery pseudoaneurysm referring to hospital during 2006-7 were included. To collect the data, checklists consisted of questions about age, sex, patients� chief complaints, clinical signs, organ paresthesia, edema, purulent discharge, subcutaneous emphysema, pulse, aneurysm site, presence or absence of concurrent venous involvement and/or artriovenous fistula, way of aneurysm repair, the extent of debridement, and clinical manifestations of the limb after surgery. On a 6-month postsurgery follow up all data were recorded in related checklists. Results: Thirty-three pseudoaneurysm patients were studied. The mean age of the cases was 34/31± 11/36 years. Pain was among the patients� chief complaint. Major sign of the disease on physical examination was: palpable mass pulsating in 57.6 and non-pulsating in 15.2 of cases. For 81.8, 9.1, and 9.1 of the cases, arterial legation, excision, and arterial bypass were done, respectively. While none of the patients undergoing arterial excision and bypass had gangrene, 12.5 of the cases undergoing artery legation had gangrene and lower limb amputation. Twenty percent were positive for HCV, 28 positive for HBS and 11 positive for both HCV and HBS. In addition, 10 of the patients were positive for HIV.Conclusion: Considering the more convenient and available technique of arterial legation and also taking into account of the fact that only 10 of the patients need vascularation after legation, surgery of femoral artery legation, particularly in patients with infectious pseudoaneurysm is recommended

A new species of the jumping spider genus Evarcha (s. lat.) from southwestern Iran (Araneae: Salticidae)

Zamani, Alireza, Hosseinpour, Amin, Azizi, Koroush, Soltani, Aboozar (2017): A new species of the jumping spider genus Evarcha (s. lat.) from southwestern Iran (Araneae: Salticidae). Peckhamia 150 (1): 1-5, DOI: http://doi.org/10.5281/zenodo.509321

Security and feasibility of power line communication system

© Springer International Publishing Switzerland 2015.Power Line Communication (PLC) has the potential to become the preferred connectivity technique for providing broadband to homes and offices with advantage of eliminating the need for new wiring infrastructure and reducing the cost. The PLC channel, its characterization, standardization and applications has been well studied. However, the security of PLC has not been investigated sufficiently, and such assessments are required for prospective implementation of successful PLC communication systems. Since PLC uses power line as the medium, it has similar characteristics with wireless communications from the security perspective. This paper provides discussion of security issues and feasibility for PLC networks. The authentication and cryptographic scheme used in PLC standard is also discussed

A Systematic Review of the Effectiveness of Early Intervention and the Role of Parents in Language Development of Hearing Loss Children

Objectives: Deaf and hard-of-hearing children are slow in language development, and language deficits are common in hearing-impaired children. Here, all areas of the language, including syntax, morphology, phonology, semantic and pragmatic, are involved, and this leads to a deficiency in reading and academic skills. Evidence shows that through early intervention, we can minimize or eliminate problems of children with hearing loss. Early intervention teaches parents how to communicate with their disabled child. Methods: Internet search in databases including ISI Web of Knowledge, Embase and Pubmed from 1990 to 2014 was conducted. Key words such as children with hearing loss, deaf children, hard-of-hearing, family education program(s), early intervention, early detection, family&rsquo;s approach, parent&rsquo;s approach, and parent&rsquo;s education program(s) were searched. Results: A total of 100 articles were initially found, and only 20 articles were finally selected for the study. The inclusion criteria for the study were as follows: the article should be interventional and written in English and should be published between 1990 and 2014. Discussion: Research showed the effectiveness of early intervention in the early development of language and vocabulary. In addition, early detection of hearing loss in the first 6 months of age has a positive impact on children and families interactions and consequently, on language and vocabulary development. The primary focus in the implementation of early intervention services is to reduce the negative effects of risk factors and facilitate optimum development over time. Finally, the combination of early diagnosis and early intervention for children with hearing impairment is necessary

Physicochemical characteristics of larval habitats and biodiversity of mosquitoes in one of the most important metropolises of southern Iran

The present study aimed to investigate the roles of the physicochemical characteristics of larval habitats in biodiversity and other bionomic factors of mosquitoes in Shiraz.The physical parameters of all habitats were recorded separately. The collected mosquito larvae were identified based on morphological characters. The water samples of larval habitats were analyzed for Biochemical Oxygen Demand (BOD, mg/L), Chemical Oxygen Demand (COD, mg/L), pH, alkalinity, turbidity, total hardness (mg/L), Electrical Conductivity (EC, μS/cm), Total Dissolved Solids (TDS, mg/L), Cl2 (mg/L), and water temperature (°C). In addition, three main indices were used for surveying biodiversity.A total of 1229 larvae were collected from April to September 2018 and May to August 2019. Seven medically important mosquito species were identified morphologically. Culex quinquefasciatus and Cx. laticinctus had the highest distribution and abundance. Ecological results showed that the richness and diversity of species were higher and more stable in natural sites than in manmade places. The optimum BOD, COD, alkalinity, TDS, EC, pH, and temperature of water for mosquitoes of the studied areas were 140 mg/L, 360 mg/L, 160 mg/L, 420 mg/L, 840 μS/cm, 8.3, and 24 °C, respectively. Most mosquitoes tended to live in manmade, temporary, and sunny larval habitats with turbid water.The results provided a better understanding of the biology and ecology of mosquitoes as the most important group of disease vectors to humans and animals. Hence, they could be used to apply some safer and more environmentally friendly methods for mosquito control