Performance improvement of power plants using absorption cooling system

In the present paper, an integration of a (Lithium Bromide–Water) absorption inlet air cooling scheme to a cooled gas turbine-based combined cycle was analyzed. The waste heat energy of the exhaust gas prior to the exit of the waste heat recovery steam generator was chosen to power the cooling system. Nubaria Power Station, 120 km South East of Alexandria has been selected as a reference plant for the present study. It includes 3 generation modules, each including 2 * 250 MW gas turbine and 250 MW Steam turbine. A thermodynamic model of the overall integrated scheme of the cooling and power cycles is introduced. A parametric study of the effect of different operational conditions, namely; ambient temperature, relative humidity, compressor inlet air temperature, and part load on performance parameters was carried out. The model shows an increase of 11% in the produced electricity when the inlet air was cooled from 30 °C to 10 °C, Also, harvesting of condensed fresh water at a rate of 3.5 gm per kg of inlet air at ambient relative humidity of 60%. The model results have been verified by observing the real performance of the plant at various ambient conditions to ensure the accuracy of the model predictions. Keywords: Absorption, Inlet air cooling, Combined cycle modeling, Waste heat recover

Comparative effectiveness of adding Omega-3 or Vitamin D to standard therapy in preventing and treating episodes of painful crisis in pediatric sickle cell patients

OBJECTIVE:   Sickle Cell Anemia (SCA), also called the Sickle Cell Disease (SCD), is an inherited hematological disorder characterized by a syndrome of acute anemia and a painful crisis. The sickling hemoglobin, Hgb-S causes viscosity and inflammation of blood vessels. Eventually, the red blood cells get eliminated from the circulation process, which leads to hemolytic anemia. This study examined the comparative effectiveness of supplementation of Omega-3 or vitamin-D to standard therapy (hydroxyurea + Ibuprofen) used for prevention and treatment of pain crises in pediatric patients living with SCD. PATIENTS AND METHODS: 165 patients participated in this randomized, double-blind, standard therapy-controlled, parallel-design trial. The patients were randomly divided into three groups, receiving three capsules of either 1,000 mg Omega-3 fish oil (400 mg EPA and 300 mg DHA) or 1.5 mL vitamin-D (2,800 IU/7 ml) daily for 10 months plus the standard therapy. Lactate dehydrogenase, high-density lipoprotein (HDL), low-density lipoprotein (LDL), hematocrit, reticulocyte count, and white-blood-cell count were determined at baseline (month zero) and end of the 10th month. The pain severity was measured using the visual analog scale method (VAS). Therefore, a 10-cm ruler with a VAS design was used to determine the patient pain intensity. The baseline time point was defined as the time spot before starting to deliver the experimental medication to the patients (month zero). At that time, the biodata of the patient on the frequency of pain episodes and the rest of the variables were collected, and the baseline data were one-year retrospective data. RESULTS: Of 165 patients enrolled in the trial, 150 were included in the final analysis. At the end of the study, there was a significant increase in serum LDL and HDL in the Omega-3 group as compared with the control group (mean of 82 mg/dL vs. 57 mg/dL; p < 0.01 and mean of 47 mg/dL vs. 43 mg/dL; p < 0.028, respectively). Other laboratory parameters were significantly influenced. The number of painful crises and pain levels was significantly decreased in the Omega-3 group compared with the control group (mean of one-episode vs. mean of three episodes; p = 0.01, mean of three on pain scale vs. six on pain scale; p = 0.018). CONCLUSIONS: Results showed that Omega-3 was more effective than vitamin-D or standard treatment alone relative to pain crises and most of the other studied items. Vitamin-D was more effective than standard therapy alone. Clinicians should consider the addition of Omega-3 supplements to the standard therapy and a de-escalation dose plan for the hydroxyurea medication.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Cost-effectiveness analysis of adding omega-3 or vitamin D supplementation to standard therapy in treating painful crises of pediatric sickle cell disease patients

OBJECTIVE: Painful crises represents a predominant complication of sickle cell disease (SCD). The only approved treatments for painful crises in many countries are hydroxyurea plus potent analgesics. Our earlier clinical trial concluded that omega-3 and vitamin D had a potential therapeutic impact on painful crises. However, there is limited research evaluating their therapeutic applications and cost-effectiveness. This paper aims at comparing the cost-effectiveness of omega-3 and vitamin D supplementation to the standard therapy in treating painful crises among children with SCD. PATIENTS AND METHODS: Cost-effectiveness analyses of daily supplementation of omega-3 and vitamin D were performed. The economic evaluation was based on data derived from a prospective 10-month randomized clinical trial (n = 165 patients; 15 patients dropped). 50 patients were recruited into the omega-3 + standard therapy group (hydroxyurea and folic acid daily with ibuprofen as needed), 50 patients into the vitamin D + standard therapy group, and 50 patients receiving standard therapy alone served as a control group. Outcome measures from the randomized clinical trial were used to determine incremental effectiveness. Cost estimates were calculated from the healthcare payer's perspective. The analysis considered the improvement in various outcome measures and are presented here as percent change from baseline to determine the incremental effectiveness and the incremental cost for the treatment of both interventions. RESULTS: Adding omega-3 or vitamin D to the standard therapy was more cost-effective than standard treatment alone. Vitamin D was a cheaper but less cost-effective alternative for most outcomes between the two treatments, including LDL-C and HDL-C. It was also more cost-effective but less clinically effective in reducing vaso-occlusive crisis episodes and pain severity. Omega-3 supplementation was significantly more cost-effective than vitamin D supplementation and the standard treatment for those measures. CONCLUSIONS: The present study showed that using vitamin D and omega-3 as add-on treatments for a painful crisis in pediatric sickle cell disease could have overall cost-saving and clinical benefits. However, further studies with a longer treatment duration are needed to establish more significant effects of the interventions for better policy and clinical decision-making. © 2022 Verduci Editore s.r.l. All rights reserved.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]