30 research outputs found
Gas turbine intercoolers: introducing nanofluids—a mini-review
oolant is one of the main factors affecting the overall thermal performance of the intercooler for the gas turbine intercooled cycle. The thermal conductivity of conventional coolants, such as water, is relatively low when compared to solid conducting materials, and therefore can hinder the progress towards achieving a compact and highly effective intercooler. Nanofluids are advanced types of working fluids that contain dispersed nanoparticles in conventional basefluids, and as such possess superior thermal conductivity compared to their counterparts. In this paper, a short review on the effect of different nanofluids on the thermal performance of gas turbines intercoolers is presented for the first time. Firstly, this work reviews the different designs of intercoolers used in gas turbines intercooled cycles. Then, it explains the different types of nanofluids and their fabrication processes. The effective parameters, such as physical stability, thermal conductivity, and viscosity are also highlighted and discussed. Furthermore, the level of enhancement in the performance of intercoolers utilizing nanofluids is demonstrated and evaluated. Lastly, the current challenges and future research directions in this field are provided
The Impact of Human Resources on the Banking Sector Performance in Syria
This research deals with the relationship between some of the general characteristics of human resources in the Syrian banking sector, such as the level of education, training and experience, and the operational financial efficiency of this sector. The data for the human resources is collected from the employees of several private banks in Syria, then testing the relationship with the financial data derived from the annual financial statements published by those banks for year 2019, the same year of data collection. This study is the cornerstone of complementary studies, which is more specialized in the field of human resources and financial performance. The study concluded that there is no effect of the human resources efficiency on financial performance for year 2019, which raises the urgent need of conducting similar research for a range of years and more comprehensive study on the factors that effect financial performance whether in the Syrian market or other markets as a part of behavior analysis on financial market
Carbon-based nanofluids and their advances towards heat transfer applications—a review
Nanofluids have opened the doors towards the enhancement of many of today’s existing thermal applications performance. This is because these advanced working fluids exhibit exceptional thermophysical properties, and thus making them excellent candidates for replacing conventional working fluids. On the other hand, nanomaterials of carbon-base were proven throughout the literature to have the highest thermal conductivity among all other types of nanoscaled materials. Therefore, when these materials are homogeneously dispersed in a base fluid, the resulting suspension will theoretically attain orders of magnitude higher effective thermal conductivity than its counterpart. Despite this fact, there are still some challenges that are associated with these types of fluids. The main obstacle is the dispersion stability of the nanomaterials, which can lead the attractive properties of the nanofluid to degrade with time, up to the point where they lose their effectiveness. For such reason, this work has been devoted towards providing a systematic review on nanofluids of carbon-base, precisely; carbon nanotubes, graphene, and nanodiamonds, and their employment in thermal systems commonly used in the energy sectors. Firstly, this work reviews the synthesis approaches of the carbon-based feedstock. Then, it explains the different nanofluids fabrication methods. The dispersion stability is also discussed in terms of measuring techniques, enhancement methods, and its effect on the suspension thermophysical properties. The study summarizes the development in the correlations used to predict the thermophysical properties of the dispersion. Furthermore, it assesses the influence of these advanced working fluids on parabolic trough solar collectors, nuclear reactor systems, and air conditioning and refrigeration systems. Lastly, the current gap in scientific knowledge is provided to set up future research directions
Impact of tumor necrosis factor antagonist combination and anti-integrin therapies on body mass index in inflammatory bowel disease: A cross-sectional study
BackgroundThe impact of biologic therapies on body mass index (BMI) in patients with inflammatory bowel disease (IBD) is unclear. This study investigates any associations between BMI, type of IBD, and the type of medications taken among patients with IBD with varying weight categories.MethodsA cross sectional study was performed in an IBD tertiary care center. Data was obtained from patients with IBD attending outpatient clinics from January 1st, 2021 until November 1st, 2021. Adult patients, older than 18 years, with a diagnosis of Crohn’s disease (CD) or ulcerative colitis (UC) were recruited. The primary outcome was the association between BMI and medication used in IBD. The secondary outcome was the association between BMI and disease type and location in patients with IBD.ResultsThe study included a total of 528 patients of which, 66.5% have CD. Patients with normal weight comprises 55.9% of the participants, while those who are underweight, overweight or obese are 3.4, 28.2, and 12.5%, respectively. None of the underweight patients had UC. Among the normal weight, overweight and obese BMI categories, 34.6% vs. 36.2% vs. 31.8% had UC, respectively. Patients who are on tumor necrosis factor inhibitors (anti-TNF) with an immunomodulator (anti-TNF combination), are more likely to be overweight or obese than patients who are not on anti-TNF combination (OR 2.86, 95% CI 1.739–4.711, p < 0.001). Patients on vedolizumab are twice as likely to be overweight or obese than patients not on vedolizumab (OR 2.23, 95% CI 1.086–4.584, p < 0.05). Patients with ileocolonic CD are more likely to be overweight or obese compared to other subtypes of CD (OR 1.78, 95% CI 1.14–2.77, p = 0.01).ConclusionMany patients with IBD are either obese or overweight. Patients with IBD who are on anti-TNF combination therapy or vedolizumab monotherapy are more likely to be obese and overweight. In addition, patients will ileocolonic CD are more likely to be obese or overweight
White blood cell subpopulation changes and prevalence of neutropenia among Arab diabetic patients attending Dasman Diabetes Institute in Kuwait.
The effects of diabetes mellitus on the differential white blood cell count are not widely studied in the Arab populations. The objective of this cross-sectional, retrospective study is to assess the influence of chronic diabetes mellitus on white blood cell counts, absolute neutrophil (ANC) and lymphocyte counts (ALC) as well as the prevalence of benign ethnic neutropenia among Arabs attending the Dasman Diabetes Institute (DDI) in Kuwait.1,580 out of 5,200 patients registered in the DDI database qualified for our study. Age, gender, HbA1c and creatinine levels, estimated glomerular filtration rate as well as average WBC, ANC and ALC levels, presence of diabetes-associated complications and anti-diabetic medications were analyzed. Our results showed the mean value of the WBC was 7.6 ± 1.93 x 109/L (95% CI: 2.95-17.15). The mean ANC was 4.3 x 109/L (95% CI: 0.97-10.40) and mean ALC was 2.5 x 109/L (95% CI: 0.29-10.80). Neutropenia (ANC: <1.5 x 109/L) was detected in fifteen patients (0.94%). Six patients (0.4%) fulfilled the definition of lymphopenia (ALC < 1 x109/L). Patients with an HbA1c ≥ 7% and those taking at least 3 anti-diabetic medications showed higher values for ANC and ALC. Patients with diabetes-associated neuropathy or nephropathy displayed higher mean ANC values. Our study was limited by overrepresentation of patients over 50 years old compared to those under 50 as well as selection bias given its retrospective nature.Our study showed that patients with poorly controlled diabetes displayed higher ANC and ALC levels. In addition, patients with DM-associated complications showed higher ANC levels. This finding would suggest that DM exerts a pro-inflammatory influence on differential WBC counts. Our study also showed that the prevalence of benign ethnic neutropenia was lower than previously reported in other studies
Correlation between mean HBA1C values and mean ALC and ANC among Arab diabetic patients attending Dasman Diabetes Institute.
<p>Correlation between mean HBA1C values and mean ALC and ANC among Arab diabetic patients attending Dasman Diabetes Institute.</p
Medications prescribed and presence of polypharmacy among diabetic patients attending DDI.
<p>Medications prescribed and presence of polypharmacy among diabetic patients attending DDI.</p
Differences in mean ANC and mean ALC values and patient demographics among Arab diabetic patients attending DDI.
<p>Differences in mean ANC and mean ALC values and patient demographics among Arab diabetic patients attending DDI.</p
Polypharmacy and mean ANC and mean ALC among Arab diabetic patients attending DDI.
<p>Polypharmacy and mean ANC and mean ALC among Arab diabetic patients attending DDI.</p