Chilled Water Storage Feasibility with District Cooling Chiller in Tropical Environment

The difficulties of efficiently operating a chiller cooling system are manifest in the high-energy consumption under partial-cooling loads. The performance of a chiller cooling system declines when operating away from the optimal design conditions, which is typically 75% of chiller capacity. One pathway has been found to overcome this problem using multiple smaller chillers within the same chiller plant, accompanied by a smart control system that is designed and constructed based on the cooling demand profile. Thermal energy storage integration with chiller cooling system is proposed to shave the cooling peak demand. This can be achieved by storing chilled water during the lower electricity-tariff period by the thermal energy storage system, which will then be discharged during the higher tariff-rate, thus, aiming for sustainable operating cost. The present paper studies the feasibility of sensible thermal energy storage to be integrated with two chillers, of 30-ton capacity each, under hot-and-humid climates. A computational model validated with experimental results is developed for three chiller cooling system case scenarios. The smart control scenario, as well as the thermal energy storage scenario results, showed great potential for energy and electricity cost saving. In addition, the carbon dioxide emissions reduction is calculated based on the amount of energy saving

A Standardized RNA Isolation Protocol for Yam (Dioscorea alata L) cDNA Library Construction

For the purpose of constructing yam cDNA libraries, attempts to isolate high quality RNA using several previously reported protocols were unsuccessful. Therefore a protocol was standardized for yam total RNA isolation by using guanidium buffer at the Department of Biology, Virginia State University. The RNA isolated using this standardized protocol was high in quality and led to successful good quality cDNA library construction and identification of functional ESTs in yam

Effect of different concentrations of chitosan coating on storage life and quality characteristics of Papaya (Carica Papaya L.)

Mature green stage of papaya fruits were treated with different concentrations of chitosan at 0, 0.5, 0.75 and 1%, and stored at 13±1 °C for 28 days to study the effect of these concentrations on the storage life and maintaining quality of papaya. Chitosan concentrations 0.75 and 1% showed the best control effect on decay compared with 0% (Control) and 0.5%. At 0.75 and 1% of chitosan, flesh firmness maintained resulted in prolonging in storage life of 28 and 26 days compared with 21 and 19 days, respectively for 0.5 and 0%. Furthermore, they were significantly decreased the weight loss of fruit. All of the treatments inhibited increase of soluble solid contents and pH values of pulp fruits after 21 days of storage at 13 ± 1°C. Titratable acidity and ascorbic acid were higher for coated fruits (0.5, 0.75 and 1%) compared with uncoated fruits. Concern treatments of chitosan at 0.75 and 1% improve papaya fruit quality and resistance to decay

Thrombocytopenia in systemic lupus erythematosus patients and its association with antiphospholipid antibodies

Introduction: Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease, characterized by immune-mediated inflammation in different organs. The course of the disease is characterized by relapses and remissions, and the degree of severity of the clinical manifestations is greatly affected by the number and nature of the various organ affection. The death rate in patients with SLE is still significant, and it may be due to lupus activity, when vital organs are affected, the complications of treatment especially infections or long-term complications, such as cardiovascular disorders. Objective: To detect the relation between thrombocytopenia in SLE patients and presence antiphospholipid antibodies.Patients and methods: This study was a cross-sectional study included 100 SLE patients who attended to Sohag University Hospitals. Patients included in this study were classified as SLE patients according to either the 2012 SLICC criteria or the new 2017 ACR/EULAR SLE classification criteria. All of the participants were subjected to the following: Full history, full clinical examination, routine investigations, ANA by immunofluorescence, and ANA profile for the most common 19 autoantibodies by immunoblot. All of the participants were subjected to detection of serum titers of all antiphospholipid antibodies (aPLs) including lupus anticoagulant (LA), anti-cardiolipin (aCL) and anti-beta2-glycoprotein I (ab2GPI).Results: In this study, we demonstrated that aPLs are strongly associated with increased risk of thrombocytopenia in SLE patients. We identified aPL profiles, especially LA and IgM isotypes, as biomarkers for the risk stratification of thrombocytopenia in SLE patients.Conclusions: We concluded that aPLs are strongly associated with increased risk of thrombocytopenia in SLE patients

Preoperative evaluation of patients with ovarian masses using the risk of malignancy index 4 model

Objective: To evaluate the performance of the RMI 4 in discriminating benign from malignant ovarian masses. Study Design: Cross-sectional study. Setting: Assiut Women Health Hospital- Egypt. Materials and methods: This was an observational cross-sectional study involving 91 patients at Women\u27s Health Hospital, Assiut University, Egypt during the period between January, 2016 and January, 2017. Women with ovarian masses planned for surgical management were recruited from the outpatient gynecology clinic of the hospital. Risk of malignancy index (RMI 4) was calculated for all study participants. Biopsies obtained from the ovarian masses after surgical intervention were sent to the pathology lab for histopathological examination. The histopathologic diagnosis of the ovarian masses is considered the gold standard for diagnosis. Results: The mean age of patients in the benign group was 34.83±16.28 years versus 43.43±15.91 in the malignant group. There were 12 postmenopausal patients (15.6%) in the benign group versus 4 postmenopausal patients (28.6%) in the malignant group (p=0.0001). An ultrasound score of 4 was recorded in 85.7% of patients in the malignant group versus only 6.5% in the benign group (p=0.0001). Additionally, tumor size ≥ 7 cm was observed in 85.7% of patients in the malignant group versus 55.8% in the benign group (p=0.0001). The mean value of CA-125 was significantly higher in malignant group than the benign group (142.09±41.50 versus 54.51±32.86 ml, respectively) with p=0.01. RMI 4 had a sensitivity of 75%, specificity of 97.3%, PPV of 85.7%, NPV of 94.8 % and an overall accuracy of 93.4%. Conclusions: RMI 4 is a simple and reliable tool in the primary evaluation of patients with ovarian masses. It can further be used to discriminate benign from malignant ovarian masses with high sensitivity and accuracy

Is Prolonged Sitting a Risk Factor in Developing Hemorrhoids and Anal Fissures?

Background: Anal fissures and hemorrhoids are common anal conditions. They cause significant morbidity, social embarrassment, and work absenteeism. In addition, they form a significant workload on the healthcare system. Nevertheless, the etiology of these conditions is still contentious. It has been observed that hemorrhoids and anal fissures are associated with prolonged sitting. This study aims to investigate this observation.Methods: This is a case–control study. We compared 81 patients with symptomatic and endoscopically proven hemorrhoids and/or anal fissures with 162 controls with no symptoms or endoscopic evidence of perianal disease. The study was conducted at Khartoum North Teaching Hospital (KNTH) endoscopy unit between January and December 2019. Demographic data, sitting hours per day, and endoscopic findings of patients and controls were recorded in a proforma. The cases and controls were matched for age, sex, and bowel habits. Data were analyzed and compared using the SPSS version 23.Results: The mean sitting hours for cases was 5.99 (SD 3.4) whereas that for controls was 4.0 (SD 3.0) with a highly significant difference (P < 0.001). Sitting for 5 hr or more per day (exposure) was associated with an increased risk of developing hemorrhoids and/or anal fissures [odds ratio 3.68, 95% CI: 2.1–6.47].Conclusion: The study showed that sitting down for 5 hr or more per day might increase the risk of developing hemorrhoids and/or anal fissures. This finding could help in the prevention and treatment of these diseases and the reduction of recurrences

May Measurement Month 2017: an analysis of blood pressure screening in Sudan-Northern Africa and Middle East

Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. Sudan has the second highest prevalence of hypertension in North Africa. One in four people with a non-communicable disease has hypertension. May Measurement Month (MMM) is a global initiative, aimed at raising awareness of high BP to act as a temporary solution to the lack of screening programs worldwide. The MMM screening survey provided an opportunity to correlate between unique risk factors and BP levels among Sudanese population. Such an approach allows for directing efforts towards setting the appropriate preventive measures as opposed to disease treatment. An opportunistic cross-sectional survey of volunteers aged ≥18 was carried out in May 2017. Blood pressure measurement, the definition of hypertension and statistical analysis followed the standard MMM protocol. The study was conducted at 100 sites distributed in four states: Khartoum, Gezira, Blue Nile, and Kassala. Overall, a total of 44 413 participants were enrolled in the survey. After imputation, 7332 out of 44 118 participants with an available mean of the second and third readings had hypertension (16.6%). A total of 6956 (15.9%) participants were found to have hypertension of the 43 742 who were not receiving treatment. Among participants who were on treatment, 155 out of 374 (41.3%) had uncontrolled BP. After adjusting for age and sex, systolic and diastolic BP's were significantly higher in those receiving antihypertensive treatment, with a previous history of stroke and with elevated body mass index. Systolic BP was significantly higher in people with diabetes and with previous myocardial infarction. Smoking was associated with increased diastolic BP and decreased systolic BP. Alcohol intake as well as BP measurement on left vs. right arm had no association with BP reading. The MMM17 was the largest BP screening campaign ever held in the country. A considerable percentage of detected hypertensives were not on treatment with a significant proportion of uncontrolled hypertension among those on treatment. These results suggest that opportunistic screening can identify significant numbers with raised BP

Computational fluid dynamics simulation of an Inert Particles Spouted Bed Reactor (IPSBR) system

A novel system for contacting gases and liquids, suitable for many applications involving gas-liquid contact such as CO2 capture and brine desalination, has been simulated and experimentally validated. The system comprises a vertical vessel with gas and liquid ports and inert particles that enhance mixing and provide a high gas-liquid interfacial area. A low gas flow rate was statistically demonstrated and experimentally verified to be the optimum condition for CO2 capture and brine desalination; however, the gas velocity can have a considerable effect on the motion of inert particles inside the reactor. Uniform particles motion ensures good mixing within the reactor and hence efficient absorption and stripping process. A computational fluid dynamics (CFD) model, namely Eulerian model, presented in this paper, will help demonstrate the effect of mixing particles at specific conditions on the gas and liquid velocities inside the reactor, gas and liquid volume distribution through reactor, and eddy viscosities stresses of the mixing particles. A mesh-independent study was conducted to demonstrate the independency of mesh structure and size on the output responses. A quasi-steady state was attained to ensure the stability and feasibility of the selected model. The assembled model exhibits remarkable applicability in determining the optimum mixing particles densities, volume ratios, and sizes to ensure best velocity distribution and gas spreading inside the reactor and accordingly enhance the associated chemical reactions.Research funding: Abu Dhabi National Oil Company, Refining Research Center, Abu Dhabi, UAE (Grant no. 21N224). https://dx.doi.org/10.13039/501100002672 .Scopu

Comprehensive optimization of the dispersion of mixing particles in an inert-particle spouted-bed reactor (Ipsbr) system

Effective gas dispersion and liquid mixing are significant parameters in the design of an inert-particle spouted-bed reactor (IPSBR) system. Solid particles can be used to ensure good mixing and an efficient rate of mass and heat transfer between the gas and liquid. In this study, computational fluid dynamics (CFD) coupled with the discrete phase model (DPM) were developed to investigate the effect of the feed gas velocity (0.5-1.5 m/s), orifice diameter (0.001-0.005 m), gas head (0.15-0.35 m), particle diameter (0.009-0.0225 m), and mixing-particle-to-reactor-volume fraction (2.0-10.0 vol.%) on the solid mass concentration, average solid velocity, and average solid volume fraction in the upper, middle, and conical regions of the reactor. Statistical analysis was performed using a second-order response surface methodology (RSM) with central composite design (CCD) to obtain the optimal operating conditions. Selected parameters were optimized to maximize the responses in the middle and upper regions, and minimize them in the conical region. Such conditions produced a high interfacial area and fewer dead zones owing to good particle dispersion. The optimal process variables were feed gas velocity of 1.5 m/s, orifice diameter of 0.001 m, gas head of 0.2025 m, a particle diameter of 0.01 m, and a particle load of 0.02 kg. The minimum average air velocity and maximum air volume fraction were observed under the same operating conditions. This confirmed the novelty of the reactor, which could work at a high feed gas velocity while maintaining a high residence time and gas volume fraction.This research was funded by the ADNOC Refining Research Center, Abu Dhabi, United Arab Emirates, grant number 21N224, https://dx.doi.org/10.13039/501100002672 (accessed on 20 September 2021). The authors would like to express their sincere gratitude to Jawad Mustafa from Chemical Engineering Department at the UAE University for his valuable help and assistance.Scopu