67 research outputs found

    Recovery of Natural Antioxidants from Fruit Juice Industry Residuals by Ultrasound-Assisted Extraction and Response Surface Methodology

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    Fruit processing industries produce by-products that are good sources of natural antioxidants. These residuals are non-toxic and available in large quantities. A central composite design (CCD) and response surface methodology (RSM) were used to optimize experimental conditions. The processing variables were solvent type, solvent to solid ratio, ethanol concentration, temperature, and time. The responses were total phenolic content (TPC), scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, and yield. The optimal conditions were 70% ethanol— water mixture as a food grade solvent, temperature of 35 °C and extraction time 60 min for obtaining extracts with maximum of total phenolic content. Predicted values for total phenolic content in pear, apricot, and peach were 24.7, 19.3, and 10.4 mg gallic acid equivalents per 100 g fruit residual, respectively

    Numerical Optimization of an Array of Triangular Microchannels using Constructal Theory

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    In the present study, an arrangement of triangular microchannels with different contact angles is analyzed and optimized following the guidelines provided by the constructal theory to reach to the maximum heat removal rate. This investigation is performed analytically and numerically. Based on the obtained results, it is emerged that this optimization is independent of the number and the type of the arrangement of the microchannels. It is also observed that increasing the pressure drop through the triangular microchannels decreases the optimal hydraulic diameter. Numerical results recommend that the microchannel with contact angle of 60° possesses the highest heat transfer rate at a given pressure drop, and decreasing the contact angle of the triangular cross-section leads to lower heat transfer rates. Comparing the analytical and numerical results of the optimal hydraulic diameter of the microchannel heat sinks, a reasonable agreement is observed; however, due to some assumptions which are considered at the analytical method, the analytical predictions of the configurations having the highest heat transfer rate are inaccurate. Therefore, the numerical optimization should be used to choose the configuration with the highest cooling capacity

    Effect of Reverting Channels on Heat Transfer Performance of Microchannels with Different Geometries

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    This study investigated the effect of reverting microchannels inside a heat sink on increase of cooling rate as well as the effect of their different configurations on maximum temperature and pressure drop. Based on the convection heat transfer mechanism, selection of the embedded microchannels’ configurations including circular, square and triangular ones, was studied for geometric optimization of the discussed heat sinks. The goal was to minimize the thermal resistance through optimizing the geometries. The volume ratio was defined as the ratio of the volume taken up by microchannels to the solid volume (portion of the heat sink not occupied by microchannels) and was considered as 0.05. According to the results, in addition to obtaining a more uniform temperature distribution, reverting channels remarkably reduced the maximum temperature. Moreover, the heat sink with square shape showed less thermal resistance as compared to the other two geometries

    Case Report: “Spina Ventosa” Tuberculous Dactylitis in a 2 Year Old Boy - A Very Rare Disease

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    Tuberculous infection of metacarpals, metatarsals and phalanges is known as tuberculous dactylitis. There is a spindle shaped expansion of the short tubular bones due to tuberculous granuloma. Hence it is also known as spina ventosa. In our case, a two year old boy with a swelling in the metacarpal was provisionally diagnosed as enchondromata while the possibility of spina ventosa was kept in mind. He was posted for excision of the metacarpal followed by bone grafting. Histopathological examination report confirmed it as spina ventosa

    Prevalence of Amblyopia in Iranian Children

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    BACKGROUND AND OBJECTIVE: Amblyopia is one of the common eye diseases in children and the risk of vision loss is possible. Therefore, the aim of this study is systematic review and meta-analysis in order to align the studies on the prevalence of amblyopia in Iranian children. METHODS: In this systematic review and meta-analysis relevant articles in scientific databases including SID, Science Direct and Medline (PubMed) and Google Scholar in March 1999- February 2017, using the Persian and English Keywords of Amblyopia, children, Iran. FINDINGS: In the review of internal and external journals and search on SID databases 22 articles, PubMed 126 articles, Science Direct 112 articles and 116 Google Scholar search engines were obtained. Then the articles that had the initial conditions for entry into the study were 162 cases based on preliminary studies, with the elimination of 214 repetitive articles. Finally, removing 120 articles unrelated to the topic of the study and removing 24 articles in the secondary studies ultimately 18 papers entered the meta-analysis process. The overall Prevalence of amblyopia in Iranian children was 5.4 % (Cl-95%: 3.1%-9.1%). CONCLUSION: According to the results of this study, the prevalence of amblyopia in Iranian children is high

    Neonatal severe bacterial infection impairment estimates in South Asia, sub-Saharan Africa, and Latin America for 2010.

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    BACKGROUND: Survivors of neonatal infections are at risk of neurodevelopmental impairment (NDI), a burden not previously systematically quantified and yet important for program priority setting. Systematic reviews and meta-analyses were undertaken and applied in a three-step compartmental model to estimate NDI cases after severe neonatal bacterial infection in South Asia, sub-Saharan Africa, and Latin America in neonates of >32 wk gestation (or >1,500 g). METHODS: We estimated cases of sepsis, meningitis, pneumonia, or no severe bacterial infection from among estimated cases of possible severe bacterial infection ((pSBI) step 1). We applied respective case fatality risks ((CFRs) step 2) and the NDI risk among survivors (step 3). For neonatal tetanus, incidence estimates were based on the estimated deaths, CFRs, and risk of subsequent NDI. RESULTS: For 2010, we estimated 1.7 million (uncertainty range: 1.1-2.4 million) cases of neonatal sepsis, 200,000 (21,000-350,000) cases of meningitis, 510,000 cases (150,000-930,000) of pneumonia, and 79,000 cases (70,000-930,000) of tetanus in neonates >32 wk gestation (or >1,500 g). Among the survivors, we estimated moderate to severe NDI after neonatal meningitis in 23% (95% confidence interval: 19-26%) of survivors, 18,000 (2,700-35,000) cases, and after neonatal tetanus in 16% (6-27%), 4,700 cases (1,700-8,900). CONCLUSION: Data are lacking for impairment after neonatal sepsis and pneumonia, especially among those of >32 wk gestation. Improved recognition and treatment of pSBI will reduce neonatal mortality. Lack of follow-up data for survivors of severe bacterial infections, particularly sepsis, was striking. Given the high incidence of sepsis, even minor NDI would be of major public health importance. Prevention of neonatal infection, improved case management, and support for children with NDI are all important strategies, currently receiving limited policy attention

    Energy recovery during liquefied natural gas regasification

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    Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.In the liquefied natural gas (LNG) regasification process, the cold exergy can be recovered as electric power. For this purpose, in the present study, a simple open Brayton cycle was considered as a base cycle and its efficiency was improved by adding different equipment step by step. This procedure resulted in the investigation of four different cycles. The comparison of the results led to the proposal of a combined cycle that could recover the LNG cold energy most efficiently. This cycle consists of three parts; an LNG directly expanding cycle, a middle-pressure close Brayton cycle with nitrogen as working fluid, and finally an open gas turbine power cycle. All the cycles were analyzed based on the first and second laws of thermodynamics. Finally, the effects of different parameters upon the thermal and exergetic efficiencies were examined.ej201
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