38 research outputs found

    Experimentation on Optimal Configuration and Size of Thin Cylinders in Natural Convection

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    In this paper, an experimental study of laminar, steady state natural convection heat transfer from heated thin cylinders in an infinite air medium has been reported. Two electrically heated cylinders having the same slenderness ratio (L/D) i.e. 6.1 but different diameters i.e. 3.8 cm and 5.08 cm were used. 105 experiments were carried out to study the effect of diameter and inclination angle of thin cylinder on natural convection heat transfer. After mandatory corrections of radiation and endcap heat losses, convective heat transfer results were presented in the form of local and average dimensionless numbers. For vertical configuration of thin cylinder, Nusselt number was varied from 52.99 to 95.10 corresponding to 1.28×108≤Ra*L≤1.08×1010. While for horizontal configuration,Nusselt number was varied from 10.74 to 17.78 corresponding to 9.42×104≤Ra*D≤8.17×106. Results were compared with the published data and found satisfactory as the maximum percentage difference was only 3.09%. The essence of research is that the heat transfer coefficient increases with decrease in diameter and increase in inclination angle. Smoke flow visualization was done to capture patterns of fluid flow. Finally, comparison was made to quantify increase in Nusselt number from slender cylinder as compared to the flat plate

    Convection Heat Transfer from Heated Thin Cylinders Inside a Ventilated Enclosure

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    Experimental study was conducted to determine the effect of velocity of axial fan, outlet vent height, position, area, and aspect ratio (h/w) of ventilated enclosure on convection heat transfer. Rectangular wooden ventilated enclosure having top and front transparent wall was made up of Perspex for visualization, and internal physical dimensions of box were 200 mm × 200 mm × 400 mm. Inlet vent was at bottom while outlet vents were at the side and top wall. Electrically heated cylindrical heat source having 6.1 slenderness ratio was fabricated and hanged at the centre of the enclosure. To calculate heat transfer rates, thermocouples were attached to the inner surface of heat source with silica gel. Heat source was operated at constant heat flux in order to quantify the effect of velocity of air on heat transfer. It was observed that average Nusselt number was increased from 68 to 216 by changing velocity from 0 to 3.34 m/s at constant modified Grashof number i.e. 5.67E+09. While variation in outlet height at the front wall did not affect heat transfer in forced convection region. However, Nusselt number decreased to 5% by changing the outlet position from top to the front wall or by 50% reduction in outlet area during forced convection. Mean rise in temperature of enclosure increased from 8.19 K to 9.40 K by increasing aspect ratio of enclosure from 1.5 to 2 by operating heat source at constant heat flux i.e. 541.20 w/m2

    RDSP: Rapidly Deployable Wireless Ad Hoc System for Post-Disaster Management

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    In post-disaster scenarios, such as after floods, earthquakes, and in war zones, the cellular communication infrastructure may be destroyed or seriously disrupted. In such emergency scenarios, it becomes very important for first aid responders to communicate with other rescue teams in order to provide feedback to both the central office and the disaster survivors. To address this issue, rapidly deployable systems are required to re-establish connectivity and assist users and first responders in the region of incident. In this work, we describe the design, implementation, and evaluation of a rapidly deployable system for first response applications in post-disaster situations, named RDSP. The proposed system helps early rescue responders and victims by sharing their location information to remotely located servers by utilizing a novel routing scheme. This novel routing scheme consists of the Dynamic ID Assignment (DIA) algorithm and the Minimum Maximum Neighbor (MMN) algorithm. The DIA algorithm is used by relay devices to dynamically select their IDs on the basis of all the available IDs of networks. Whereas, the MMN algorithm is used by the client and relay devices to dynamically select their next neighbor relays for the transmission of messages. The RDSP contains three devices; the client device sends the victim's location information to the server, the relay device relays information between client and server device, the server device receives messages from the client device to alert the rescue team. We deployed and evaluated our system in the outdoor environment of the university campus. The experimental results show that the RDSP system reduces the message delivery delay and improves the message delivery ratio with lower communication overhead.Comment: 23 pages, 12 figures, accepted for publication in Sensors 202

    Efficacy of Insecticides against Fall Armyworm, Spodoptera frugiperda (Lepidoptera, Noctuidae) in Maize

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    Fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) is most destructive specie of genus Spodoptera for several agricultural crops. In Pakistan\u27s Sindh province, the invasive fall armyworm Spodoptera frugiperda was first documented causing serious maize damage in 2019. There is need to develop management strategies against this pest in the country. The current study was conducted to check the toxicity of different insecticides against FAW in maize field. The results showed among tested insecticides, deltamethrin was recorded most toxic insecticide followed by chlorantraniliprole and emamectin benzoate. At 1d days after first spray, least number of larvae were recorded with deltamethrin (0.07 larvae/plant), chlorantraniliprole (0.11d larvae/plant) and emamectin benzoate (0.13 larvae/plant). After three days application of first spray, significantly a minimum number of larvae were recorded with deltamethrin (1.11bcd larvae/plant) chlorantraniliprole (1.13d larvae/plant) and emamectin benzoate (1.17d larvae/plant). The maximum and minimum population of larvae was recorded at 1st day of first spray and 14 days of spray, respectively. The least number of larvae were recorded at 14 days of second spray. At 14 days after 2nd spray, 0.07ab, 0.10e and 0.10de larvae per plant were recorded with deltamethrin, chlorantraniliprole and emamectin benzoate, respectively

    Genetics of combined pituitary hormone deficiency: Roadmap into the genome era

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    The genetic basis for combined pituitary hormone deficiency (CPHD) is complex, involving 30 genes in a variety of syndromic and nonsyndromic presentations. Molecular diagnosis of this disorder is valuable for predicting disease progression, avoiding unnecessary surgery, and family planning. Weexpect that the application of high throughput sequencing will uncover additional contributing genes and eventually become a valuable tool for molecular diagnosis. For example, in the last 3 years, six new genes have been implicated in CPHD using whole-exome sequencing. In this review, we present a historical perspective on gene discovery for CPHD and predict approaches that may facilitate future gene identification projects conducted by clinicians and basic scientists. Guidelines for systematic reporting of genetic variants and assigning causality are emerging. We apply these guidelines retrospectively to reports of the genetic basis of CPHD and summarize modes of inheritance and penetrance for each of the known genes. In recent years, there have been great improvements in databases of genetic information for diverse populations. Some issues remain that make molecular diagnosis challenging in some cases. These include the inherent genetic complexity of this disorder, technical challenges like uneven coverage, differing results from variant calling and interpretation pipelines, the number of tolerated genetic alterations, and imperfect methods for predicting pathogenicity.Wediscuss approaches for future research in the genetics of CPHD.Fil: Fang, Qing. University of Michigan; Estados UnidosFil: George, Akima S.. University of Michigan; Estados UnidosFil: Brinkmeier, Michelle L.. University of Michigan; Estados UnidosFil: Mortensen, Amanda H.. University of Michigan; Estados UnidosFil: Gergics, Peter. University of Michigan; Estados UnidosFil: Cheung, Leonard Y.M.. University of Michigan; Estados UnidosFil: Daly, Alexandre Z.. University of Michigan; Estados UnidosFil: Ajmal, Adnan. University of Michigan; Estados UnidosFil: Pérez Millán, María Inés. University of Michigan; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Bilge Ozel, A.. University of Michigan; Estados UnidosFil: Kitzman, Jacob. University of Michigan; Estados UnidosFil: Mills, Ryan E.. University of Michigan; Estados UnidosFil: Li, Jun Z.. University of Michigan; Estados UnidosFil: Camper, Sally. University of Michigan; Estados Unido

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Sodium Perturbations After Pituitary Surgery

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    Sodium perturbations are a common complication after pituitary surgery, with hyponatremia being the most frequent. Postoperative assessments should be tailored to the early and late periods, and monitoring sodium perturbations is recommended. Cerebral salt wasting is rare after pituitary surgery, and diagnosis and management can be challenging. Providing patient counseling and close postoperative follow-up is important to effectively manage diabetes insipidus and reduce hospital readmissions due to sodium perturbations
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