157 research outputs found

    Design, Fabrication and Testing of Hybrid Parabolic Dish Concentrator, Stirling Engine & PCM-Storage in Oman

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    This work outlines the conceptualization, design, fabrication and parameters that influence the operation of direct hybridization of solar parabolic dishes with the thermal energy storage in phase change material (PCM) and hybrid Stirling engine. This mathematical method consists of two different sizes of parabolic dishes, PCM-storage and hybrid Stirling engine. The hybrid Stirling engine was used reflective heat to electrical energy in direct and indirect ways. The direct way involved using the sunrays directly from the parabolic dishes into the engine to generate energy. This was done simultaneously while charging the PCM-storage system for later use. For the indirect way, stored heat energy in the PCM-storage was used to supply heat energy to the Stirling engine for applications at night. Tests were carried out to ensure the system performs optimally based on the design. Each part of prototype model was first tested alone and then later on as part of the complete system of the prototype model. This was carried out continuously over a period of 24hover a number of days. The result from the experiments showed the system was designed to work for 24h,which depends on efficiency of parabolic concentrator, Stirling engine, heat transfer, and storage. The system combines the solar parabolic concentrator and solar energy storage connected in one system. The design, fabrication and testing of each part as well as the complete system were presented. Result presented hybrid Stirling engine proved promising, it was working, as it showed the ability to increase energy production from morning until midday and decreases as the sunset approaches. Also, PCM- storage system proved was working, as it showed the ability to store heat production from morning until sunset approaches and the ability to supply hybrid Stirling engine at night. This project has shown positive steps towards the future of solar thermal technology; one major finding and benefit from this design is that energy generated during the day can be stored for applications during the night when there is no solar radiation. The design also offers the flexibility of adjusting storage area for more space. Moreover, the entire system is affordable, less cumbersome, and with greater ease of movement

    Modified Le Fort I Osteotomy and Genioplasty for Management of Severe Dentofacial Deformity in β-Thalassaemia Major: Case report and review of the literature

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    β-thalassaemia major is an autosomal recessive form of haemoglobinopathy that is characterised by complete lack of production of the β-chains resulting in multiple complications that include severe anaemia, failure to thrive and skeletal abnormalities. Facial deformities induced by β-thalassaemia major are rare and are very challenging to treat from a surgical point of view. We report a 33-year-old female patient with β-thalassaemia major who presented to the Dental & Maxillofacial Surgery Department, Sultan Qaboos University Hospital, Muscat, Oman, in 2017 with gross dentofacial skeletal deformity contributing to her psychosocial issues. The facial deformity was corrected surgically by excision of the enlarged maxilla, modified Le Fort I osteotomy and advancement genioplasty. This case highlights the pre-operative preparation, surgical management, encountered complications and treatment outcome within 24 months of follow-up.Keywords: Beta-Thalassaemia; Thalassaemia Major; Cooley's Anemia; Le Fort Osteotomy; Genioplasty; Dentofacial Deformities; Case Report; Oman

    Basic Education Students’ Perceptions on Sustainable Healthy Lifestyles and Disease Prevention Methods in Light of Some Variables in the Sultanate of Oman

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    هدفت الدراسة تعرف تصورات طلبة التعليم الأساسي بسلطنة عُمان عن الأنماط الصحية المستدامة وطرائق الوقاية من الأمراض في ضوء بعض المتغيرات. استخدمت الدراسة المنهج الوصفي. ولتحقيق هدف الدراسة؛ طُبِّقَتْ أداة الاستبانة، التي تكوَّنت من (36) عبارة، موزَّعة على محورين؛ هُمَا: الأنماط الصحية، والوقاية من الأمراض. وحُسِبَ ثبات الأداة؛ باستخدام طريقتَيْ: ثبات الاتساق الداخلي؛ حيث بلغ معامل كرونباخ ألفا (0.808)، وثبات التجزئة النصفية، وبلغ (0.753). وقد طُبِّقَتِ الدراسة على عَيِّنَة مكوَّنة من (3570)؛ من طلبة الصفين التاسع، والعاشر الأساسيَّيْنِ. وخَلُصَتْ نتائج الدراسة إلى وجود تصورات إيجابية لدى طلبة التعليم الأساسي عن محور الأنماط الصحية المستدامة، حيث حصل نمط النظافة الشخصية على أعلى نمط صحي، يليه نمطي النشاط الرياضي، والتغذية، ثم يأتي نمط النوم باعتباره أقل نمط صحي، وتظهر النتائج أيضًا وجود تصورات إيجابية في محور طرائق الوقاية من الأمراض، كما كشفت الدراسة عن عدم وجود فروق دالة إحصائيًّا في متغيِّرات: النَّوْع الاجتماعي، والمحافظة التعليمية في محوري: الأنماط الصحية، وطرائق الوقاية من الأمراض، وعليه أَوْصَتْ الدراسة بتعزيز وَعْي طلبة التعليم الأساسي بأهمية ممارسة الأنماط الصحية المستدامة

    Pathogenic and Non-Pathogenic Microbial Presence in Ventilator Associated Pneumonia Patients in Intensive Care Unit and Safety Protocols Under Surveillance of Healthcare Provider: A Research Study

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    Ventilator-associated pneumonia (VAP) is a common hospital-acquired infection that is associated with longer stays in intensive care units (ICUs) and under mechanical ventilation for more than 48 hours. This article explores the prevalence and impact of VAP on mortality and morbidity, emphasizing the microbial associations involved in hospital-acquired infections. Various infections, including Lung infections, surgical site infections, sepsis, and urinary tract infections, are discussed, along with their associated microorganisms. Diagnostic criteria for VAP and related infections are outlined, highlighting the importance of microbiological testing for accurate diagnosis. The underlying factors for VAP acquisition in ICU patients are identified, and prompt antibiotic initiation is emphasized as a critical first-line defense against VAP. In this study, we have populated data from 100 ICU patients, among which 45 were suffering from VAP. It was found that female patients (57.40%) were more affected than male patients (30.43%). The decreasing PaO2 level was seen to be the early sign of infection. It was found that the time of ventilation was the major factor influencing the VAP. The most common organism causing infection in our study was found to be Staphylococcus Aureus (45.1%). The prognosis of early-onset VAP was 35.55% while compared to Late-onset VAP 64.44%. When compared to VAP and Non-VAP patients there was not very huge difference with 55% and 45% respectively. The other factor was age and position. Implementation of Prevention strategies, such as protective environments and HEPA filtration systems, is proposed to reduce VAP incidence. Proper diagnosis, treatment, and prevention are crucial to combatting VAP and enhancing patient outcomes in hospital settings

    Search for new physics in multijet events with at least one photon and large missing transverse momentum in proton-proton collisions at 13 TeV

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    A search for new physics in final states consisting of at least one photon, multiple jets, and large missing transverse momentum is presented, using proton-proton collision events at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 137 fb−1, recorded by the CMS experiment at the CERN LHC from 2016 to 2018. The events are divided into mutually exclusive bins characterized by the missing transverse momentum, the number of jets, the number of b-tagged jets, and jets consistent with the presence of hadronically decaying W, Z, or Higgs bosons. The observed data are found to be consistent with the prediction from standard model processes. The results are interpreted in the context of simplified models of pair production of supersymmetric particles via strong and electroweak interactions. Depending on the details of the signal models, gluinos and squarks of masses up to 2.35 and 1.43 TeV, respectively, and electroweakinos of masses up to 1.23 TeV are excluded at 95% confidence level

    Measurements of inclusive and differential cross sections for the Higgs boson production and decay to four-leptons in proton-proton collisions at s \sqrt{s} = 13 TeV

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    Measurements of the inclusive and differential fiducial cross sections for the Higgs boson production in the H → ZZ → 4ℓ (ℓ = e, μ) decay channel are presented. The results are obtained from the analysis of proton-proton collision data recorded by the CMS experiment at the CERN LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb−1. The measured inclusive fiducial cross section is 2.73 ± 0.26 fb, in agreement with the standard model expectation of 2.86 ± 0.1 fb. Differential cross sections are measured as a function of several kinematic observables sensitive to the Higgs boson production and decay to four leptons. A set of double-differential measurements is also performed, yielding a comprehensive characterization of the four leptons final state. Constraints on the Higgs boson trilinear coupling and on the bottom and charm quark coupling modifiers are derived from its transverse momentum distribution. All results are consistent with theoretical predictions from the standard model

    Search for Scalar Leptoquarks Produced via τ-Lepton-Quark Scattering in pppp Collisions at s=13TeV\sqrt{s}=13 TeV

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    The first search for scalar leptoquarks produced in τ-lepton–quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138  fb1^{−1}. The reconstructed final state consists of a jet, significant missing transverse momentum, and a τ lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-τ-quark coupling strength

    Controversy and consensus on the management of elevated sperm DNA fragmentation in male infertility: A global survey, current guidelines, and expert recommendations

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    Purpose Sperm DNA fragmentation (SDF) has been associated with male infertility and poor outcomes of assisted reproductive technology (ART). The purpose of this study was to investigate global practices related to the management of elevated SDF in infertile men, summarize the relevant professional society recommendations, and provide expert recommendations for managing this condition. Materials and Methods An online global survey on clinical practices related to SDF was disseminated to reproductive clinicians, according to the CHERRIES checklist criteria. Management protocols for various conditions associated with SDF were captured and compared to the relevant recommendations in professional society guidelines and the appropriate available evidence. Expert recommendations and consensus on the management of infertile men with elevated SDF were then formulated and adapted using the Delphi method. Results A total of 436 experts from 55 different countries submitted responses. As an initial approach, 79.1% of reproductive experts recommend lifestyle modifications for infertile men with elevated SDF, and 76.9% prescribe empiric antioxidants. Regarding antioxidant duration, 39.3% recommend 4–6 months and 38.1% recommend 3 months. For men with unexplained or idiopathic infertility, and couples experiencing recurrent miscarriages associated with elevated SDF, most respondents refer to ART 6 months after failure of conservative and empiric medical management. Infertile men with clinical varicocele, normal conventional semen parameters, and elevated SDF are offered varicocele repair immediately after diagnosis by 31.4%, and after failure of antioxidants and conservative measures by 40.9%. Sperm selection techniques and testicular sperm extraction are also management options for couples undergoing ART. For most questions, heterogenous practices were demonstrated. Conclusions This paper presents the results of a large global survey on the management of infertile men with elevated SDF and reveals a lack of consensus among clinicians. Furthermore, it demonstrates the scarcity of professional society guidelines in this regard and attempts to highlight the relevant evidence. Expert recommendations are proposed to help guide clinicians
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