6 research outputs found

    Modeling of Thermal Distributions by Analyzing the Heat Tolerance of A Robotic Gripper Pivot Exposed to Heated Electronics

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    There are several applications in the aerospace, automotive and energy industries, for example, that often require high fidelity modeling or problems involving structural mechanics, heat transfer, or electromagnetic. Finite element analysis (FEA) is a popular method for solving the underlying partial differential equations (PDE) for these problems. 3D finite element analysis or 3D-FEA accurately captures the physics of these problems. The relevance of this study is to show how to set up finite element analysis (FEA) simulations and leverage the model of the environment to solve problems typically encountered by engineers and scientists in a variety of fields such as aerospace, automotive and energy. This study analyzes the behavior of mechanical components under different physical effects and shows a thermal analysis of a commercial KUKA YouBot robotic arm component by finding temperature distributions, figures, code, and test results for multiple materials. The developed model allows understanding and assessing the responsive component under loading, vibration or heat and determining deformation stresses among many things to select the best material and even prevent failure or undesired resonance as an example. These systems are typically modeled using partial differential equations or PDEs that capture the underlying physics of the problem and FEA is just one of the most common methodologies to solve this type of equation. The linear regression model can be a good predictive model that represents the relationship between thermal conductivity and max temperature to avoid undesired performance of the robotic arm

    Enhancement of Energy Transfer Efficiency for Photovoltaic (PV) Systems by Cooling the Panel Surfaces

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    The thermal coefficient of a solar photovoltaic (PV) panel is a value that is provided with its specification sheet and tells us precisely the drop in panel performance with rising temperature. In desert climates, the PV panel temperatures are known to reach above 70 degrees centigrade. Exploring effective methods of increasing energy transfer efficiency is the issue that attracts researchers nowadays, which also contributes to reducing the cost of using solar photovoltaic (PV) systems with storage batteries. Temperature handling of solar PV modules is one of the techniques that improve the performance of such systems by cooling the bottom surface of the PV panels. This study initially reviews the effective methods of cooling the solar modules to select a proper, cost-effective, and easy to implement one. An active fan-based cooling method is considered in this research to make ventilation underneath the solar module. A portion of the output power at a prespecified high level of battery state-of-charge (SOC) is used to feed the fans. The developed comparator circuit is used to control the power ON/OFF of the fans. A Matlab-based simulation is employed to demonstrate the power rate improvements and that consumed by the fans. The results of simulations show that the presented approach can achieve significant improvements in the efficiency of PV systems that have storage batteries. The proposed method is demonstrated and evaluated for a 1.62 kW PV system. It is found from a simultaneous practical experiment on two identical PV panels of 180 W over a full day that the energy with the cooling system was 823.4 Wh, while that without cooling was 676 Wh. The adopted approach can play a role in enhancing energy sustainability

    Enhancement of Energy Transfer Efficiency for Photovoltaic (PV) Systems by Cooling the Panel Surfaces

    Full text link
    The thermal coefficient of a solar photovoltaic (PV) panel is a value that is provided with its specification sheet and tells us precisely the drop in panel performance with rising temperature. In desert climates, the PV panel temperatures are known to reach above 70 degrees centigrade. Exploring effective methods of increasing energy transfer efficiency is the issue that attracts researchers nowadays, which also contributes to reducing the cost of using solar photovoltaic (PV) systems with storage batteries. Temperature handling of solar PV modules is one of the techniques that improve the performance of such systems by cooling the bottom surface of the PV panels. This study initially reviews the effective methods of cooling the solar modules to select a proper, cost-effective, and easy to implement one. An active fan-based cooling method is considered in this research to make ventilation underneath the solar module. A portion of the output power at a prespecified high level of battery state-of-charge (SOC) is used to feed the fans. The developed comparator circuit is used to control the power ON/OFF of the fans. A Matlab-based simulation is employed to demonstrate the power rate improvements and that consumed by the fans. The results of simulations show that the presented approach can achieve significant improvements in the efficiency of PV systems that have storage batteries. The proposed method is demonstrated and evaluated for a 1.62 kW PV system. It is found from a simultaneous practical experiment on two identical PV panels of 180 W over a full day that the energy with the cooling system was 823.4 Wh, while that without cooling was 676 Wh. The adopted approach can play a role in enhancing energy sustainability

    Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

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    © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    © 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research
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