123 research outputs found

    Reasons for irregular use of ferrous sulfate tablet in women referred to health centers in Bourojen city, 2005-2006

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    چکیده: زمینه و هدف: خانم های باردار و شیرده از جمله گروههای در معرض خطر ‌کم خونی فقر آهن می باشند. با وجود برنامه مدون در ارتباط با مصرف قرص آهن توسط مادران، آمار به دست آمده نشان میدهد حدود 67 درصد زنان باردار و شیرده قرص آهن را صحیح و منظم مصرف نمی کنند. لذا این مطالعه با هدف بررسی علل مصرف نامنظم قرص آهن در خانم های باردار و شیرده مراجعه کننده به مراکز بهداشتی درمانی شهر بروجن انجام شد. روش بررسی:در این مطالعه توصیفی – تحلیلی که در مراکز بهداشتی درمانی شهر بروجن در سال 85-1384 انجام گرفت، 270 نفر خانم که در دوره 16 هفتگی حاملگی الی 2 ماهگی پس از زایمان قرار داشتند به روش دردسترس انتخاب و طی مصاحبه حضوری به سؤالات پرسشنامه حاوی اطلاعات دموگرافیک، چگونگی مصرف قرص آهن، نگرش و عملکرد مادران در این خصوص پاسخ دادند. از آزمونهای کای دو، من ویتنی و ویلکاکسون و کروسکال والیس جهت تجزیه و تحلیل آْماری اطلاعات استفاده شد. یافته ها: نتایج نشان داد که 1/33 مادران قرص آهن را مرتب و منظم مصرف می کردند، 8/56 نامنظم و 2/10 اصلا مصرف نمی‌کردند. بین مصرف نامنظم قرص آهن و سطح اقتصادی - اجتماعی خانواده و تعداد زایمان ارتبــاط معنی داری وجود نداشت. از علل مصرف نامنظم قرص آهن 4/48 مادران فراموش کردن وعده های مصرف دارو، 4/12 تهوع و استفراغ حاملگی و 4/16 عدم آگاهی نسبت به لزوم مصرف آهن را ذکر کردند. بین تعداد زایمان و یا حاملگی، سن فرد و شاغل بودن با آگاهی، نگرش و عملکرد آنان ارتباط معنی دار وجود نداشت (05/0

    Spatial distribution and assemblage structure of foraminifera in Nayband Bay and Haleh Estuary, north-west of the Persian Gulf

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    The spatial distribution of benthic foraminiferal assemblage of Nayband Bay and Haleh Estuary in the North-West of the Persian Gulf, was explored during 2011-2012. The relationship between spatial pattern of foraminifera assemblages and the ambient factors (i.e. water temperature, salinity, pH, dissolved oxygen, sediment grain size distribution, sediment organic content, and CaCO3 concentration of sediments) was measured. The most abundant benthic foraminifera species which were found in the studied area include Ammonia beccarii, Eponides repandus, Quinqueloculina sp., Elphidium sp. The two most abundant species belongs to Rotaliidae family. The specimen groups presented in the study area were somehow the same, and their relative abundance did not vary tremendously in sites consisting of foraminifera assemblages. The fauna shows affinities to those of the southern coastline of the Persian Gulf and also the Oman Sea. The BIO-ENV analysis identified temperature, salinity, pH, and total organic matter as the major environmental variables influencing the infaunal pattern. Generally foraminiferal populations were sparse in the study area, which may be due to the low depth and consequently, low distribution of foraminiferal specimens

    SCALE DEPOSITS IN POROUS MEDIA AND THEIR REMOVAL BY EDTA INJECTION

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    Formation damage has been observed in several oil reservoirs and production equipment in Iranian oil fields. Laboratory and field testing confirmed that the primary cause of damage was the build-up of calcium carbonate, calcium sulfate and strontium sulfate scale either in the perforation tunnels or in the formation sandstone nears the wellbore. Conventional acid treatments could dissolve this scale, but scale precipitation from the spent acid caused rapid productivity decline. A scale removal treatment with Na2H2EDTA has been developed that can effectively dissolve scale and chelate the dissolved metal ions. Chelation of the dissolved scale prevents scale reprecipitation. This study describes the results of an experimental and theoretical study on the removal of formation damage resulting from scale formation in porous media. An experimental investigation was undertaken to look into the possible causes of the injectivity loss in a typical Iranian oilfield. Sets of experimental investigations were undertaken with different objectives in mind. Glass and sand bead packs were used to test the experimental set up and to observe the general behaviour of scale formation and removal by ethylene diamine tetra acetic acid (EDTA) to determine its possible effects on the permeability of the porous medium

    Short view of leukemia diagnosis and treatment in Iran

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    Background: Early diagnosis and treatment of leukemia patients remains a fundamental aim in clinical oncology, especially in developing country. Present study highlights the basic requirements of these patients in Iran. Better understanding of these issues may lead to improve the healthcare standards toward leukemia diagnosis and treatment. Methods: This descriptive study included 101 specialists in hematology-oncology and pathology serving in oncology centers. The participants were then asked to fill out a standard questionnaire on the issues around diagnosis and treatment of blood malignancies. Results: According to specialists, unfair distribution of facilities across the country, delayed diagnosis of disease, absence of psychological support for patients, and insufficient financial support were the main reasons of inappropriate diagnosis and treatment in leukemia patients. Conclusions: Our results show that making an amendment to health policies by preparing well-equipped medical centers in all provinces, improving the morale of patients through consultation during the process of treatment, and above all, subsiding leukemia patients' financial problems will promote the health standard regarding the leukemia diagnosis and treatment in Iran. © 2015, Tehran University of Medical Sciences (TUMS). All rights reserved

    Study on hybrid combustion of aero-suspensions of boron-aluminum powders in a quiescent reaction medium

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    © 2017. The present research deals with a hybrid combustion of aluminum/boron dust particles in a heterogeneous quiescent reaction medium with spatially discrete heat sources. A developed thermal model is employed to estimate flame propagation speed in a reaction medium. The burning velocity and minimum ignition energy are studied parametrically as a function of dust concentration and particle diameter for different percentages of boron powder in a hybrid mixture of aluminum/boron dust cloud. The model shows that the addition of boron powder as a component of the mixture decreases the burning rate and causes a higher amount of minimum ignition energy needed for ignition, owing to the role of boron as a heat sink. Comparison of the simulation results with the available experimental data shows that the model captures the flame propagation speed as a function of particle concentration, except at very low concentrations

    A computational fluid dynamics study of laminar forced convection improvement of a non-Newtonian hybrid nanofluid within an annular pipe in porous media

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    Porous inserts and nanofluids are among the conventional methods for the amelioration of heat transfer in industrial systems. The heat transfer rate could also be improved by utilizing porous substances with a higher thermal conductivity in these systems. This research work presents a two-dimensional (2D) numerical examination of the laminar forced convection of an Al2O3-CuO-carboxy methyl cellulose (CMC) non-Newtonian hybrid nanofluid within an annular pipe in a porous medium. The porous medium was inserted within two inner or outer wall cases. For hybrid nanofluid flow modeling in porous media, a Darcy–Brinkman–Forchheimer formulation was employed. Additionally, a power-law technique was utilized as a fluid viscosity model for the considered non-Newtonian fluid. The governing equations were discretized according to the finite volume method (FVM) using the computational fluid dynamics (CFD) software package ANSYS-FLUENT. The cylinder walls’ thermal boundary conditions were exposed to a constant heat flux. For various Darcy numbers, the impacts of different volume fractions of the hybrid nanofluid (0% to 5%), the total Nusselt number, the pressure drop, and the performance number (PN) were evaluated. The outcomes indicate that the heat transfer coefficient increases considerably with a decrease in the Darcy number (0.1 to 0.0001), as well as with an increase in the porous thickness ratio. Moreover, it was found that the nanoparticles’ increased volume fraction would ameliorate the heat transfer and, more considerably, the PN factor. Furthermore, according to the outcomes in both cases I and II for a constant porous thickness ratio and Darcy number (rp=1,Da=0.0001) and a high volume fraction (φ=5%), the maximum total Nusselt number reached 1274.44. Moreover, applying a volume fraction of 5% with Da=0.1 and rp=1 reached the highest value of the PN index equal to 7.61, which is augmented as roughly 88% compared to the case of a zero volume fraction

    A Comprehensive Survey of 'Metamaterial Transmission-Line Based Antennas: Design, Challenges, and Applications'

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    In this review paper, a comprehensive study on the concept, theory, and applications of composite right/left-handed transmission lines (CRLH-TLs) by considering their use in antenna system designs have been provided. It is shown that CRLH-TLs with negative permittivity (epsilon < 0) and negative permeability (mu < 0) have unique properties that do not occur naturally. Therefore, they are referred to as artificial structures called "metamaterials". These artificial structures include series left-handed (LH) capacitances (C-L), shunt LH inductances (L-L), series right-handed (RH) inductances (L-R), and shunt RH capacitances (C-R) that are realized by slots or interdigital capacitors, stubs or via-holes, unwanted current flowing on the surface, and gap distance between the surface and ground-plane, respectively. In the most cases, it is also shown that structures based on CRLH metamaterial-TLs are superior than their conventional alternatives, since they have smaller dimensions, lower-profile, wider bandwidth, better radiation patterns, higher gain and efficiency, which make them easier and more cost-effective to manufacture and mass produce. Hence, a broad range of metamaterial-based design possibilities are introduced to highlight the improvement of the performance parameters that are rare and not often discussed in available literature. Therefore, this survey provides a wide overview of key early-stage concepts of metematerial-based designs as a thorough reference for specialist antennas and microwave circuits designers. To analyze the critical features of metamaterial theory and concept, several examples are used. Comparisons on the basis of physical size, bandwidth, materials, gain, efficiency, and radiation patterns are made for all the examples that are based on CRLH metamaterial-TLs. As revealed in all the metematerial design examples, foot-print area decrement is an important issue of study that have a strong impact for the enlargement of the next generation wireless communication systems

    A comprehensive survey of "metamaterial transmission-line based antennas: design, challenges, and applications"

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    In this review paper, a comprehensive study on the concept, theory, and applications of composite right/left-handed transmission lines (CRLH-TLs) by considering their use in antenna system designs have been provided. It is shown that CRLH-TLs with negative permittivity (ε < 0) and negative permeability (μ < 0) have unique properties that do not occur naturally. Therefore, they are referred to as artificial structures called "metamaterials". These artificial structures include series left-handed (LH) capacitances (CL), shunt LH inductances (LL), series right-handed (RH) inductances (LR), and shunt RH capacitances (CR) that are realized by slots or interdigital capacitors, stubs or via-holes, unwanted current flowing on the surface, and gap distance between the surface and ground-plane, respectively. In the most cases, it is also shown that structures based on CRLH metamaterial-TLs are superior than their conventional alternatives, since they have smaller dimensions, lower-profile, wider bandwidth, better radiation patterns, higher gain and efficiency, which make them easier and more cost-effective to manufacture and mass produce. Hence, a broad range of metamaterial-based design possibilities are introduced to highlight the improvement of the performance parameters that are rare and not often discussed in available literature. Therefore, this survey provides a wide overview of key early-stage concepts of metematerial-based designs as a thorough reference for specialist antennas and microwave circuits designers. To analyze the critical features of metamaterial theory and concept, several examples are used. Comparisons on the basis of physical size, bandwidth, materials, gain, efficiency, and radiation patterns are made for all the examples that are based on CRLH metamaterial-TLs. As revealed in all the metematerial design examples, foot-print area decrement is an important issue of study that have a strong impact for the enlargement of the next generation wireless communication systems

    Impedance Bandwidth Improvement of a Planar Antenna Based on Metamaterial-Inspired T-Matching Network

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    In this paper a metamaterial-inspired T-matching network is directly imbedded inside the feedline of a microstrip antenna to realize optimum power transfer between the front-end of an RF wireless transceiver and the antenna. The proposed T-matching network, which is composed of an arrangement of series capacitor, shunt inductor, series capacitor, exhibits left-handed metamaterial characteristics. The matching network is first theoretically modelled to gain insight of its limitations. It was then implemented directly in the 50-Omega feedline to a standard circular patch antenna, which is an unconventional methodology. The antenna's performance was verified through measurements. With the proposed technique there is 2.7 dBi improvement in the antenna's radiation gain and 12% increase in the efficiency at the center frequency, and this is achieved over a significantly wider frequency range by a factor of approximately twenty. Moreover, there is good correlation between the theoretical model, method of moments simulation, and the measurement results
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