49 research outputs found

    Locating Post Offices Using Fuzzy Goal Programming and Geographical Information System (GIS)

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    This paper deals with the problem of locating new post offices in a megacity. To do so, a combination of geographicalinformation system (GIS) and fuzzy goal programming (FGP) is used. In order to locate new offices, first six types of servicefacilities with high levels of interactions with post offices are defined. Then, aspiration level of proximity for each servicefacility is determined. Based on these values, a fuzzy goal programming model is constructed to find potential locations offacilities. In order to determine the optimal locations among potential facilities, a maximal covering location problem(MCLP) is solved and results are reported. Results show that although the current state is near-optimal, for future expansionsof the network, the government should spend money on central and southern parts of this megacity

    Control of Grid-Following Inverters under Unbalanced Grid Conditions

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    Effect of Workplace Noise on Hearing Ability in Tile and Ceramic Industry Workers in Iran: A 2-Year Follow-Up Study

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    Introduction. Noise as a common physical hazard may lead to noise-induced hearing loss, an irreversible but preventable disorder. Annual audiometric evaluations help detect changes in hearing status before clinically significant hearing loss develops. This study was designed to track hearing threshold changes during 2-year follow-up among tile and ceramic workers. Methods. This follow-up study was conducted on 555 workers (totally 1110 ears). Subjects were divided into four groups according to the level of noise exposure. Hearing threshold in conventional audiometric frequencies was measured and standard threshold shift was calculated for each ear. Results. Hearing threshold was increased during 2 years of follow-up. Increased hearing threshold was most frequently observed at 4000, 6000, and 3000 Hz. Standard threshold shift was observed in 13 (2.34%), 49 (8.83%), 22 (3.96%), and 63 (11.35%) subjects in the first and second years of follow-up in the right and left ears, respectively. Conclusions. This study has documented a high incidence of noise-induced hearing loss in tile and ceramic workers that would put stress on the importance of using hearing protection devices

    To Improve Total Knee Prostheses Performance Using Three-Phase Ceramic-Based Functionally Graded Biomaterials

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    One of the common issues that occur after total knee replacement surgery is the aseptic loosening. The problem usually occurs after about 15 years from the surgery. The destructive effects of residual particles due to wear, the stress shielding effect, and micro-movements are the causative factors for this type of loosening. In this research, using the advantages of functionally graded biomaterials (FGBM), it is tried to design a prosthetic system that can reduce the above-mentioned effects. For this purpose, the materials used in the most important part of the prosthesis system, i.e., the femoral part are redesigned so that the bioactivity between the prosthesis and bone, and the stress applied to the adjacent tissues increase simultaneously. In addition, to reduce the effect of wear at contact areas, wear-resistant biocompatible ceramics such as alumina and zirconia are used. The value of stress at the bone-prosthesis interface and adjacent tissues is the most important parameters. Two types of three-phase ceramic-based FGBMs are recommended. The prosthesis with three-phase hydroxyapatite-titanium-zirconia has increased the average stress in the bone tissues around high-risk areas up to 71.8% with respect to a commonly used Cr-Co prosthesis. The result for the prosthesis with three-phase hydroxyapatite-titanium-alumina is up to 65%, respectively. At bone-prosthesis interfaces, an increase of 92% in the stress for both zirconia-based and alumina-based is seen. Briefly, the recommended FGBMs can improve the bone-prosthesis performance in all desired indices

    Efficacy of Low-Level Laser Therapy in the Management of Tinnitus due to Noise-Induced Hearing Loss: A Double-Blind Randomized Clinical Trial

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    Background. Several remedial modalities for the treatment of tinnitus have been proposed, but an effective standard treatment is still to be confirmed. In the present study, we aimed to evaluate the effect of low-level laser therapy on tinnitus accompanied by noise-induced hearing loss. Methods. This was a double-blind randomized clinical trial on subjects suffering from tinnitus accompanied by noise-induced hearing loss. The study intervention was 20 sessions of low-level laser therapy every other day, 20 minutes each session. Tinnitus was assessed by three methods (visual analog scale, tinnitus handicap inventory, and tinnitus loudness) at baseline, immediately and 3 months after the intervention. Results. All subjects were male workers with age range of 30–51 years. The mean tinnitus duration was 1.85±0.78 years. All three measurement methods have shown improved values after laser therapy compared with the placebo both immediately and 3 months after treatment. Laser therapy revealed a U-shaped efficacy throughout the course of follow-up. Nonresponse rate of the intervention was 57% and 70% in the two assessment time points, respectively. Conclusion. This study found low-level laser therapy to be effective in alleviating tinnitus in patients with noise-induced hearing loss, although this effect has faded after 3 months of follow-up. This trial is registered with the Australian New Zealand clinical trials registry with identifier ACTRN12612000455864)

    Hearing Thresholds Changes after MRI 1.5T of Head and Neck

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    INTRODUCTION: Exposure to high intensity noise produced by MRI is a cause for concern. This study was conducted to determine the temporary and permanent effects of exposure to noise created by performing MRI on the hearing threshold of the subjects using conventional and extended high frequency audiometry. METHODS: This semiexperimental study was performed on 35 patients referred to Shahid Rahnemoun Hospital for head and neck MRI due to different clinical conditions. The hearing threshold of patients was measured before, immediately after, and 24 hours after performing 1.5 Tesla MRI using conventional and extended high frequency audiometry. SPSS version 18 was used to compare the mean hearing thresholds before and after MRI using paired T test and repeated measures analysis. RESULTS: Comparison of auditory thresholds in conventional and extended high frequencies before and immediately after MRI showed a significant shift at 4 KHz (P = 0.008 and P = 0.08 for right and left ears), 6 KHz (P = 0.03 and P = 0.01 for right and left ears), and 14 KHz (P =0.03 and P = 0.31 for right and left ears). However, there was no significant difference between audiometric thresholds before and 24 hours after MRI. CONCLUSION: Noise due to 1.5 Tesla MRI can only cause transient threshold shift

    Shift Work Effects and Pregnancy Outcome: A Historical Cohort Study

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    Objective: Employed mothers face considerable amount of hazards. Especially shift work can impact pregnant women by affecting some hormones. This study was conducted to assess the adverse effects of shift work on pregnancy outcomes. Materials and methods: This historical cohort study was conducted in 2017 in order to assess the effect of shift work on pregnancy outcomes. The subjects were consecutively selected from pregnant women, which referred to Al Zahra and Shahid Beheshti hospitals, Isfahan, Iran for their pregnancy care. The effect of shift work on pregnancy and labor complications (low birth weight, small for gestational age, pre-eclampsia and eclampsia, intra-uterine growth retardation, spontaneous abortion, preterm delivery, excessive bleeding during labor, and type of labor) was assessed. The effect was adjusted for occupation and number of children as well. Data were analyzed by SPSS (ver. 17) usingT-test, chi-Square test and logistic regression analysis. Results: Totally, 429 pregnant women entered the study. There was not a statistically significant difference between morning and shift workers regarding age. It was found that shift work probably increases the incidence of small for gestational age, pre-eclampsia and eclampsia, intra-uterine growth retardation, spontaneous abortion, and preterm delivery, but after adjustment for job and number of children the effect was observed only on preterm delivery. Conclusion: Working in a rapid cycling schedule of shift work may cause an increase in the incidence of preterm delivery in pregnant mothers

    Bilateral Numerous Warts in Upper and Lower Eyelids, in Middle-Aged Man

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    Background: Warts are small, usually painless growths on the skin caused by a virus called human papillomavirus (HPV). Most, but not all, are generally harmless [1,2]. Warts can be disfiguring and embarrassing. Sometimes they itch or hurt (particularly on the feet). Some warts spread through sex. But in The eyelids are rare. Viral warts are a common skin condition, which can range in severity from a minor nuisance that resolve spontaneously to a troublesome, chronic condition [3-5]. Many different treatments are available but because warts were very large, we use a surgical procedure (excision).Purpose: To evaluate the efficacy of cut out the wart (excision) by surgery.Materials/Patients: In this case report, 56 years old man have been reported with upper and lower eyelid involvement in both eyes. Expressed warts came the age of 20 and around the eyelids of both eyes and then grows within 5 years, Sized warts at presentation were 1 to 5 mm until warts on eyelids make adverse effects on vision. Warts were also seen around the patient’s neck. He had no other illnesses. The patient’s mother had two warts 4 to 5 mm around her nose. We have treated the warts eye in vali Asr hospital, Birjand University of Medical Sciences. Pathologist also reported Verruca Vulgarism. Patient after surgery was visit in terms of recurrence and fortunately it was not a problem.</p

    Marfan Syndrome in an Iranian Family: A Case Series

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    Marfan syndrome (MFS) is a genetic disorder which is inherited by autosomal dominant traits. In MFS, lens displacement and cardiovascular involvement are important causes of morbidity and mortality in the clinical course of the disease. In this case study, the ocular involvement in a family with severe penetration of MFS is reported. Twelve members of a family (father, two daughters, three sons, and six grandchildren) had MFS. Lens ectopia was the most common ophthalmic involvement among the family (100%). Other ocular involvements were as follows; Hypoplastic iris or ciliary’s muscle hypoplasia (50%), on gated eyeball (42%), flat cornea (30%), glaucoma and cataract (25%), retinal detachment (16%). Three members of the family underwent eye surgery including lens extraction, glaucoma surgery and retinal surgery
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