This paper presents a numerical study of heat transfer through a downstream annulus using water as the working fluid within the laminar flow region. The annulus consisted of an outer twisted square ...duct and an inner circular pipe. A three-dimensional formulation was used to solve the Navier-Stokes equations numerically for the laminar flow system with a low Reynolds number. Three parameters were used in the numerical simulation: the length of the twisted square (
:
,
) the inner diameter of the inner circular pipe (
:
); and the twist angle (θ:
° (smooth),
°,
°,
°). Numerical calculations were conducted on sixteen twisted square duct heat exchangers, with water flowing within a Reynolds number range of
–
. The results were illustrated as a profile of the thermal enhancement factor, the friction factor and the Nusselt number. The results show that the twisted outer duct of the heat exchanger can create a swirl flow along the length of the heat exchanger. It also caused a boundary layer separation-reattachment on the wall of the inner pipe. Moreover, an increase in the twist angle increased the Nusselt number by
%, and the friction factor was also increased as the annular gap of the heat exchanger decreased.
This study examines the usefulness of computed tomography (CT) scans in evaluating patients with dizziness in the emergency department (ED).
Medical records of patients presented with complaints of ...dizziness or vertigo to the ED of a tertiary university hospital and underwent head CT scans from July 2015 to June 2018 were reviewed. The patients’ demographic information, presenting symptoms, and final head CT scan and Magnetic resonance imaging (MRI) results were collected. Stepwise logistic regressions were used to analyze data.
A total of 326 dizzy patients were included in this study. The majority of the patients (83.1%) were older than 44 years. Acute vertigo pattern of dizziness was detected among 50.6% of the patients and was more common among females than males (p < 0.001). Of these 326 patients who underwent head CT scans, 49 (15%) had abnormal findings with acute ischemic stroke was the most common one. A total of 191 patients underwent follow-up studies. MRI accounted for 70% of the follow-up studies. Of the 134 patients who received MRI of the brain, 36 (27%) had abnormal findings. A significant correlation of RBCs level, presence of other symptoms, and frequency of episodes with the presence of vertigo (p < 0.001) was found.
The study's findings indicate low effectiveness of head CT scan compared to MRI for dizziness management. Future studies are suggested to provide more insights into the cost-effectiveness and utility of head CT scans and MRI in providing valuable findings.
•The majority of the dizzy patients presented to the emergency were older than 44 years.•Acute vertigo was detected among 50.62% of the patients and more common among elderly females.•Lower effectiveness of CT scan compared to MRI in the diagnosing and management of dizziness.•Significant correlation of RBCs level, presence of other symptoms, and frequency of episodes with the presence of vertigo.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background
Although Subarachnoid Hemorrhage (SAH) is an emergency condition, its epidemiology and prognosis remain poorly understood in Africa. We aim to explore the clinical presentations, outcomes, ...and potential mortality predictors of primary SAH patients within 3 weeks of hospitalization in a tertiary hospital in Sudan.
Methods
We prospectively studied 40 SAH patients over 5 months, with 3 weeks of follow-up for the symptomatology, signs, Glasgow coma scale (GCS), CT scan findings, and outcomes. The fatal outcome group was defined as dying within 3 weeks.
Results
The mean age was 53.5 years (SD, 6.9; range, 41–65), and 62.5% were women. One-third (30.0%) were smokers, 37.5% were hypertensive, two-thirds (62.5%) had elevated blood pressure on admission, 37.5% had >24 hours delayed presentation, and 15% had missed SAH diagnosis. The most common presenting symptoms were headache and neck pain/stiffness, while seizures were reported in 12.5%. Approximately one-quarter of patients (22.5%) had large-sized Computed Tomography scan hemorrhage, and 40.0% had moderate size. In-hospital mortality rate was 40.0% (16/40); and 87.5% of them passed away within the first week. Compared to survivors, fatal outcome patients had significantly higher rates of smoking (50.0%), hypertension (68.8%), elevated presenting blood pressure (93.8%), delayed diagnosis (56.2%), large hemorrhage (56.2%), lower GCS scores at presentation, and cerebral rebleeding (P < 0.05 for each). The primary causes of death were the direct effect of the primary hemorrhage (43.8%), rebleeding (31.3%), and delayed cerebral infarction (12.5%).
Conclusions
SAH is associated with a high in-hospital mortality rate in this cohort of Sudanese SAH patients due to modifiable factors such as delayed diagnosis, hypertension, and smoking. Strategies toward minimizing these factors are recommended.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Abstract
Nanostructured pure and Indium doped iron oxide thin films were deposited via spray pyrolysis technique (SPT). The effects of Indium (2 and % 4) concentration was studied. X-ray diffraction ...patterns disclosed that Fe
2
O
3
films have a rhombohedral crystalline of α-Fe
2
O3 phase and their crystallite size was vary from (12.13 – 13.84) nm with Indium content. The strain(%) parameter decrease from 28.57 to 25.04, AFM images of films show changes in morphology with decreased in surface roughness from 2.75 nm to 1.7 nm with Indium 4% doping, The 3-D images and grain size distribution are illustrated that they exhibit spherical nano-grains ranged from 72.72 nm for pure Indium to 51.22 nm for 4% Indium doped Fe
2
O
3
. The transmittance decreases with increasing Indium concentration. The bandgap energy of Fe
2
O
3
thin film was 2.75 eV and it decreases to 2.55 eV for Fe
2
O
3
:4% In.
Nanostructured pure and Indium doped iron oxide thin films were deposited via spray pyrolysis technique (SPT). The effects of Indium (2 and % 4) concentration was studied. X-ray diffraction patterns ...disclosed that Fe2O3 films have a rhombohedral crystalline of α-Fe2O3 phase and their crystallite size was vary from (12.13 - 13.84) nm with Indium content. The strain(%) parameter decrease from 28.57 to 25.04, AFM images of films show changes in morphology with decreased in surface roughness from 2.75 nm to 1.7 nm with Indium 4% doping, The 3-D images and grain size distribution are illustrated that they exhibit spherical nano-grains ranged from 72.72 nm for pure Indium to 51.22 nm for 4% Indium doped Fe2O3. The transmittance decreases with increasing Indium concentration. The bandgap energy of Fe2O3 thin film was 2.75 eV and it decreases to 2.55 eV for Fe2O3:4% In.
This study proposes an evaluation and benchmarking decision matrix (DM) on the basis of multi-criteria decision making (MCDM) for young learners' English mobile applications (E-apps) in terms of ...listening, speaking, reading and writing (LSRW) skills. Benchmarking E-apps for young learners is challenging due to (a) multiple criteria, (b) criteria importance and (c) data variation. The DM was constructed on the basis of the intersection amongst evaluation criteria in terms of LSRW and E-apps for young learners. The criteria were adopted from a preschool education curriculum standard. The DM data included six E-apps as alternatives and 17 skills as criteria. Thereafter, the six E-apps were evaluated by distributing a checklist form amongst six English learning experts. These apps were subsequently benchmarked by utilising MCDM methods, namely, best-worst method (BWM) and technique for order of preference by similarity to ideal solution (TOPSIS). BWM was used for criterion weighting, whereas TOPSIS was employed to benchmark and rank the apps. TOPSIS was utilised in two contexts, namely, individual and group. In the group context, internal and external aggregations are applied. Mean was computed to ensure that the E-apps undergo a systematic ranking for objective validation. This study provides scenarios and a benchmarking checklist to evaluate and compare the proposed work with six relative studies. Results indicated that (1) BWM is suitable for criteria weighting. (2) TOPSIS is suitable for benchmarking and ranking E-apps. Moreover, the internal and external TOPSIS group decision making exhibited similar findings, with the best app being `Montessori' and the worst app being `FunWithFlupe.' (3) For objective validation, remarkable differences were observed amongst the group scores, which indicate that the internal and external ranking results are identical. (4) In the evaluation, the proposed DM revealed advantages over the six relative studies by 40.00%, 53.33%, 40.00%, 46.67%, 46.67% and 46.67%.
This study presents a detailed microfacies analysis of the Lower Triassic Mahil Formation (Khuff outcrop equivalent (KS-1)) in Jabal Akhdar, at the Saiq Plateau and Wadi Sahtan areas of Northern ...Oman.Two sections were measured and sedimentologically logged along a depositional dip profile emphasizing color, lithology, grain components, bed thickness, the nature of bed contact, lateral continuity of beds, and fossil content.One hundred and eighty fresh rock samples were collected from various lithofacies.The collected samples were thin-sectioned after blue epoxy was impregnated, and then they were half stained with Alizarin Red S and Potassium Ferricyanide for mineralogical identification.The point-counted compositions were determined by counting 300 points for each thin section to reconstruct the original components, obtain precise quantification, develop representative microfacies, and construct the depositional model for the Lower Mahil Formation.Accordingly, eighteen microfacies types representing different carbonate ramp environments were identified; two are only recognized in the Wadi Sahtan logged section, ten are restricted to the Saiq Plateau logged section, and six are common for both sections.The Lower Mahil Formation consists of backshoal (inner ramp) to foreshoal (mid-ramp) carbonate facies, with shoal (ramp crest) facies restricted to the Saiq Plateau logged section.The backshoal facies was characterized by abundant non-skeletal grains with breccia.The shoals were predominantly oolitic and intraclastic packstone-grainstone.Foreshoal carbonate facies, on the other hand, has mixed skeletal and non-skeletal grains with weakly developed hummocky cross-stratified beds.The shallow-water foraminiferal and oolitic packstone/grainstone facies are the potential reservoir intervals, whereas the wackestone facies is the non-reservoir intervals within the Lower Mahil Formation.The detailed sedimentological and microfacies analysis helped characterize the Lower Mahil Formation for better recognizing the potential reservoir vs.no-reservoir.This study can be a key reference to correlate the Lower Mahil Formation locally and regionally.
•The studied Formation is one of the most prolific reservoirs in the Middle East, and this study reveals the potential reservoir in two sections.•The main finding is that the eighteen different microfacies types were distributed randomly in three different environments.•The analysis procedure employed shown that the Saiq Plateau section is shallower than the Wadi Sahtan section.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Congenital diseases causing obstruction of the right ventricular outflow tract (RVOT) are common, but the isolated subpulmonary membrane/ring is extremely rare and can be difficult to diagnose ...precisely, especially in adults. We report a case of surgically resected isolated subpulmonic fibrous ring in a lady with mirror-image dextrocardia and abdominal situs solitus that was misdiagnosed by echocardiography as a subaortic membrane.
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