15 research outputs found

    Online Coordinated Charging of Plug-In Electric Vehicles in Smart Grid to Minimize Cost of Generating Energy and Improve Voltage Profile

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    This Ph.D. research highlights the negative impacts of random vehicle charging on power grid and proposes four practical PEV coordinated charging strategies that reduce network and generation costs by integrating renewable energy resources and real-time pricing while considering utility constraints and consumer concerns

    Age and the Length of Hospital Stay in Patients With Sepsis at the ICU Admission can Prolong the Duration of Endotracheal Intubation

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    Background: Endotracheal intubation (EI) associated with mechanical ventilation (MV) is frequently performed in critically ill patients admitted to intensive care unit (ICU) with sepsis. Objectives: This study aimed to assess the impact of important factors on the duration of tracheal intubation in patients with sepsis at the ICU admission. Methods: Adult patients admitted to the mixed medical–surgical ICUs with sepsis at the ICU admission who needs prolonged mechanical ventilation (PMV) (≥ 21 days) were included in this retrospective secondary analysis study. The primary outcome was ICU mortality. Baseline demographic and clinical characteristics of all patients were assessed as risk factors associated with the duration of MV by univariate and multivariate Binary logistic regression. Results: Eighty-five patients required more than 21 days of MV. Out of the 85 patients, 52 (61.2%) patients were intubated within 30 to 34.50 days and 33 (38.8%) patients had intubation within 34.51 to 65 days, and categorized as PMV and very prolonged MV groups, respectively. Two parameters were significantly associated with very prolonged MV which are as follows: older age 1.229 (95% CI: 1.002-1.507, P = 0.048) and long hospital stay (LOS) 2.996 (95% CI: 1.676-5.356, P < 0.001). No significant survival difference was observed between the two groups of study. (33.3% vs. 25%, P = 0.406). Conclusion: Our observations showed that the older age and LOS as pre-ICU stay in patients with positive sepsis at the ICU admission can prolong the duration of intubation. In addition, no significant survival difference was observed between patients with PMV and very prolonged MV

    Investigating the physicochemical, sensory and microbial properties of plant-based protein products (meat-free burgers) formulated using various Vicia ervilia (L.) Willd. protein isolates

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    The present study investigated the effect of using various protein isolates of Vicia ervilia (L.) Willd. (Bitter vetch; Family: Fabaceae) in formulating plant burgers on physicochemical, sensory and microbial properties of the resulting plant-based protein products. The results indicated that the plant-based protein products in the formulation of which protein isolates produced based on salt extraction methods were used, had higher rates of protein, fat and oil. On the contrary, they had lower rates of carbohydrate and moisture in contrast to the plant-based protein products formulated using protein isolates produced based on isoelectric precipitation methods. The reason for the high amount of fat and protein in these treatments can be attributed to the isolates’ production conditions, high amount of oil diffused from the product in contrast to low oil retention and absorption capacity and low level of the measured moisture in comparison with the high protein content. In the current century, due to the uneven human population growth as well as the limited growth of animal resources, the debate about protein deficiency is particularly important in developing societies. Efforts for finding abundant and cheap herbal sources of protein have led to various researches regarding the use of some such less-known legumes in developing countries. In this regard, different protein isolates of Vicia ervilia have been used in the formulation of vegetable burgers to produce a new, inexpensive and productive plant protein product in the food industry

    Is the Ratio of Retracted Iranian Papers Compatible With Their Research Growth Rate? An International Database Survey

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    Background: Retraction of articles occurs as a result of scientific misconducts or honest errors. Objectives: This study aimed to identify the frequency of retracted Iranian publications, compared to those of other countries and adjust them with influential parameters. Methods: All publications that were indexed on the Scopus database from 2008 to 2017 and then retracted, due to scientific misconduct were extracted through the Retraction Watch database and selected as the research community. To calculate the growth of retraction for each proposed country (or region), first, the rate of an absolute number of retracted papers for the years 2013-2017 was divided by the similar number for years 2008-2012, then this rate was adjusted to the retracted rate which is similarly computed for the total retracted statistics of the world. Results: Overall, 545 Iranian retracted publications from 2008 to 2017 were identified, of which 240 and 305 retracted articles were related to the first five years and the second five years of the study, respectively. The results showed that less than 1% (0.82) of all scientific articles published by Iranian researchers were retracted. However, the rate of retracted scientific articles in Iran compared to this rate in the world was significantly higher. Conclusion: Although retracted Iranian publications make up a small percentage of all Iranian publications, the number of retracted publications is increasing. It is important to recognize the reasons for scientific misconducts and to provide researchers with proper education

    Comparison of non-invasive to invasive oxygenation ratios for diagnosing acute respiratory distress syndrome following coronary artery bypass graft surgery: a prospective derivation-validation cohort study

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    Objective: To determine if non-invasive oxygenation indices, namely peripheral capillary oxygen saturation (SpO2)/ fraction of inspired oxygen (Fi O2) and partial pressure of alveolar oxygen (PAO2)/Fi O2 may be used as effective surrogates for the partial pressure of arterial oxygen (PaO2)/Fi O2. Also, to determine the SpO2/Fi O2 and PAO2/Fi O2 values that correspond to PaO2/Fi O2 thresholds for identifying acute respiratory distress syndrome (ARDS) in patients following coronary artery bypass graft (CABG) surgery. Methods: A prospective derivation-validation cohort study in the Open-Heart ICU of an academic teaching hospital. Recorded variables included patient demographics, ventilator settings, chest radiograph results, and SPO2, PaO2, PAO2, SaO2, and Fi O2. Linear regression modeling was used to quantify the relationship between indices. Receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of the threshold values. Results: One-hundred seventy-five patients were enrolled in the derivation cohort, and 358 in the validation cohort. The SPO2/Fi O2 and PAO2/Fi O2 ratios could be predicted well from PaO2/Fi O2, described by the linear regression models SPO2/Fi O2 = 71.149 + 0.8PF and PAO2/Fi O2 = 38.098 + 2.312PF, respectively. According to the linear regression equation, a PaO2/Fi O2 ratio of 300 equaled an SPO2/Fi O2 ratio of 311 (R2 0.857, F 1035.742, < 0.0001) and a PAO2/Fi O2 ratio of 732 (R2 0.576, F 234.887, < 0.0001). The SPO2/Fi O2 threshold of 311 had 90% sensitivity, 80% specificity, LR+ 4.50, LR- 0.13, PPV 98, and NPV 42.1 for the diagnosis of mild ARDS. The PAO2/Fi O2 threshold of 732 had 86% sensitivity, 90% specificity, LR+ 8.45, LR- 0.16, PPV 98.9, and NPV 36 for the diagnosis of mild ARDS. SPO2/ Fi O2 had excellent discrimination ability for mild ARDS (AUC ± SE = 0.92 ± 0.017; 95% CI 0.889 to 0.947) as did PAO2/ Fi O2 (AUC ± SE = 0.915 ± 0.018; 95% CI 0.881 to0.942). Conclusions: PaO2 and SaO2 correlated in the diagnosis of ARDS, with a PaO2/Fi O2 of 300 correlating to an SPO2/ Fi O2 of 311 (Sensitivity 90%, Specificity 80%). The SPO2/ Fi O2 ratio may allow for early real-time rapid identification of ARDS, while decreasing the cost, phlebotomy, blood loss, pain, skin breaks, and vascular punctures associated with serial arterial blood gas measurements

    Optimal scheduling of load tap changer and switched shunt capacitors in smart grid with electric vehicles and charging stations

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    Random charging of plug-in electric vehicles (PEVs) particularly during the peak load hours could impairment the performance of future smart grids. This paper presents genetic algorithms (GAs) for optimal scheduling of LTC and switched shunt capacitors (SSCs) to improve the performance of smart grid with PEV charging at consumer premises in residential feeders and PEV charging stations (PEV-CSs) in distribution networks. The forecasted daily load curves associated with PEV-CSs and residential feeders populated with PEVs are first generated and then incorporated in the GA-based optimal LTC and SSC scheduling solution. Simulation results without and with optimal scheduling are presented for a 449 node smart grid system with 5 PEV-CSs considering random and coordinated charging of 264 PEVs in 22 low voltage residential networks

    Coordination of Generation Scheduling with PEVs Charging in Industrial Microgrids

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    Conventional industrial microgrids (IMGs) consist of factories with distributed energy resources (DERs) and electric loads that rely on combined heat and power (CHP) systems while the developing IMGs are expected to also include renewable DERs and plug-in electric vehicles (PEVs) with different vehicle ratings and charging characteristics. This paper presents an electricity and heat generation scheduling method coordinated with PEV charging in an IMG considering photovoltaic (PV) generation systems coupled with PV storages. The proposed method is based on dynamic optimal power flow (DOPF) over a 24-hour period and includes security-constrained optimal power flow (SCOPF), IMG's factories constraints, PV storage constraints and PEVs dynamic charging constraints. It will utilize the generators waste heat to fulfill thermal requirements while considering the status of renewable DERs to decrease the overall cost of IMGs. To demonstrate the effectiveness of the proposed method, detailed simulation results are presented and analyzed for an 18-bus IMG consisting of 12 factories and 6 types of PEVs without/with PV generation systems operating in grid-connected and stand-alone modes. The main contribution is including PEVs with dynamic constraints that have changed the nature of scheduling formulation from a simple hourly OPF to a dynamic OPF

    Overnight coordinated charging of plug-in electric vehicles based on maximum sensitivities selections

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    The future smart grid (SG) will be populated with high penetrations of plug-in electric vehicles (PEVs) that may deteriorate the quality of electric power. The consumers will also be seeking economical options to charge their vehicles. This paper proposes an overnight maximum sensitivities selection based coordination algorithm (ON-MSSCA) for inexpensive overnight PEV charging in SG. The approach is based on a recently implemented online algorithm (OL-MSSCA) that charges the vehicles as soon as they are randomly plugged-in while considering SG generation, demand and voltage constraints. In contrast to the online approach, ON-MSSCA relies on inexpensive off-peak load hours charging to reduce the cost of generating energy such that SG constraints are not violated and all vehicles are fully charged overnight. Performances of the online and overnight algorithms are compared for the modified IEEE 23kV distribution system with low voltage residential feeders populated with PEVs
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