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Critical assessment of R410A alternatives for mini-split air conditioners in the Egyptian market

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Energy and Built Environment 2024年第3期5卷 426-445页

作者： omar m.Zaki omar Abdelaziz mechanical Power Engineering Department Faculty of EngineeringCairo UniversityGiza 12613Egypt Department of mechanical Engineering The American University in CairoAUC AvenueNew Cairo 11835Egypt

In this study,the potential implementation of three different low-GWP refrigerants(R32,R452B,and R454B)as replacements for R410A was *** study was performed using a simulation tool developed by the authors called RACHP-Lab,which is a vapor compression system simulation tool developed based on physics-based simulation for typical mini-split air *** simulation study was carried out and validated using experimental performance data of 10 different air conditioning units available in the Egyptian *** units included fixed-speed or variable-speed compressors and operated in cooling or heating ***-in replace-ment with the new refrigerants was carried *** R32,the capacity increased between 4.9%and 13%for cooling cases,and 6.3%and 12.4%for heating ***,COP did not improve in all *** R452B and R454B with direct replacement,the capacity nearly remained the same,with an increase of COP between 1.6%and 8.0%.Soft optimization was also conducted on cooling cases where compressor suction superheat,condenser subcooling,and compressor volumetric speed were optimized to maximize COP while maintaining the original capacity of R410A.R32 showed an improvement of COP over R410A between 4.6%and 15.5%,while for R452B and R454B between 2.2%and 13.2%.

关键词： Air conditioner Heat pump Alternative refrigerants Vapor compression cycle modeling

Performance Analysis of the Reconfigurable Intelligent Surfaces Communication Systems

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Journal of Communications and Information Networks 2024年第2期9卷 184-191页

作者： omar Abu Ella Department of Electrical and Electronic Engineering Misurata University2659 Zawiat AlmahjoubMisurataLibya

Reconfigurable intelligent surfaces (RIS) play a vital role in meeting the growing demand for higher data rates and reliability in wireless systems. This study focuses on analyzing the performance of RIS systems to gain a deeper understanding of their *** paper presents a mathematical analysis of the RIS system,deriving closed-form formulae that express its characteristics including signal-to-noise ratio(SNR)distribution,ergodic and effective capacity,outage,and error probability. The obtained formulae are newly derived and unconditionally valid solutions. Numerical results demonstrate a close agreement between the derived formulae and monteCarlo simulation outcomes.

关键词： ergodic capacity effective capacity outage probability bit error rate Rayleigh fading channel RISassisted communication system

Evaluation of hand infections in the emergency department using point-of-care ultrasound

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World Journal of Emergency medicine 2024年第4期15卷 283-288页

作者： David Ahmad Haidar David mintz Brandon m Wubben omar Rizvi Srikar Adhikari Department of Emergency medicine Michigan MedicineAnn Arbor 48109-1382USA University of Arizona College of medicine Tucson 85724USA Department of Emergency medicine University of IowaIowa City 52242-1009USA Department of Surgery University of Arizona College of MedicineTucson 85724USA Department of Emergency medicine University of Arizona College of MedicineTucson 85724USA

BACKGROUND:We aimed to evaluate the utility of point-of-care ultrasound(POCUS)in the assessment of hand infections that present to the emergency department(ED)and its impact on medical decision making and patient ***:We conducted a retrospective review of patients who presented to two urban academic EDs with clinical presentations concerning for skin and soft tissue infections(SSTI)of the hand between December 2015 and December *** trained POCUS fellowship physicians reviewed an ED POCUS database for POCUS examinations of the *** then reviewed patients’electronic health records(EHR)for demographic characteristics,history,physical examination findings,ED course,additional imaging studies,consultations,impact of POCUS on patient care and final ***:We included a total of 50 cases(28 male,22 female)in the final *** most common presenting symptoms and exam findings were pain(100%),swelling(90%),and erythema(74%).The most common sonographic findings were edema(76%),soft tissue swelling(78%),and fluid surrounding the tendon(57%).POCUS was used in medical decision making 68%of the time(n=34),with the use of POCUS leading to changes in management 38%of the time(n=19).POCUS use led to early antibiotic use(11/19),early consultation(10/19),and led to the performance of a required procedure(8/19).The POCUS diagnosis was consistent with the discharge diagnosis of flexor tenosynovitis 8/12 times,abscess 12/16 times,and cellulitis 14/20 ***:POCUS is beneficial for evaluating of hand infections that present to the ED and can be used as an important part of medical decision making to expedite patient care.

关键词： Ultrasound Point-of-care ultrasound Cellulitis Abscess flexor tenosynovitis

finite element analysis and experimental validation of polymer-metal contacts in block-on-ring configuration

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friction 2024年第3期12卷 554-568页

作者： K.Y.Eayal AWWAD Khosro fALLAHNEZHAD B.f.YOUSIf Ahmad mOSTAfA omar ALAJARmEH A.SHALWAN Xuesen ZENG mechanical Engineering Department Faculty of EngineeringTafila Technical UniversityTafila 66110Jordan medical Device Research Institute College of Science and EngineeringFlinders UniversitySouth Australia 5042Australia Centre for future materials University of Southern QueenslandToowoomba 4350Australia Department of manufacturing Engineering Technology Public Authority for Applied Education and TrainingKuwait 13092Kuwait

The wear profile analysis,obtained by different tribometers,is essential to characterise the wear ***,most of the available methods did not take the stress distribution over the wear profile in consideration,which causes inaccurate *** this study,the wear profile of polymer–metal contact,obtained by block-on-ring configuration under dry sliding conditions,was analysed using finite element modelling(fEm)and experimental ***’s wear equation was integrated into a developed fORTRAN-UmESHmOTION code linked with Abaqus software.A varying wear coefficient(k)values covering both running-in and steady state regions,and a range of applied loads involving both mild and severe wear regions were measured and implemented in the *** fEm was in good agreement with the *** model reproduced the stress distribution profiles under variable testing conditions,while their values were affected by the sliding direction and maximum wear depth(hmax).The largest area of the wear profile,exposed to the average contact stresses,is defined as the normal *** the critical zones were characterized by high stress concentrations reaching up to 10 times of that at the normal *** wear profile was mapped to identify the critical zone where the stress concentration is the key point in this *** surface features were examined in different regions using scanning electron microscope(SEm).Ultimately,SEm analysis showed severer damage features in the critical zone than that in the normal zone as proven by ***,the literature data presented and considered the wear features the same at any point of the wear *** this study,the normal zone was determined at a stress value of about 0.5 mPa,whereas the critical zone was at about 5.5 *** wear behaviour of these two zones showed totally different features from one another.

关键词： polymer-to-metal contact block-on-ring wear profile wear model

Ballistic design and testing of a composite armour reinforced by CNTs suitable for armoured vehicles

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Defence Technology（防务技术） 2024年第2期32卷 173-195页

作者： Evangelos Ch.Tsirogiannis Evangelos Daskalakis mohamed H.Hassan Abdalla m.omar Paulo Bartolo EODH SA Research and Development DepartmentLakkoma Chalkidikis63080Greece School of mechanical Aerospace and Civil EngineeringUniversity of ManchesterManchesterM139PLUK Singapore Centre for 3D Printing School of Mechanical and Aerospace EngineeringNanyang Technological University639798Singapore

This paper is investigating the use of composite armour reinforced by nanomaterials, for the protection of light armoured(LAV) and medium armoured military vehicles(mAV), and the interaction between the composite materials and high-performance ballistic projectiles. four armour materials, consisted of front hybrid fibre reinforced polymer cover layer, ceramic strike-face, fibre reinforced polymer intermediate layer and the metal matrix composite reinforced backplate, were manufactured and assembled by adhesive technology. The proposed laminated protection system is suitable for armoured ground vehicles;however, it could be used as armour on ground, air and naval platforms. The design of the protection system, including material selection and thickness, was elaborated depending on the performance requirements of Level 4 + STANAG 4569 military standard(projectile 14.5 mm × 114 mm API B32) and especially on a design philosophy which is analysed with the specifications. The backplate of this new composite is a hybrid material of metal matrix Composite(mmC) reinforced with carbon nanotubes(CNTs), manufactured with the use of powder metallurgy technique. The composite backplate material was morphologically, mechanically and chemically analysed. Results show that all plates are presenting high mechanical properties and ballistic characteristics, compared to commonly used armour plates. Real military ballistic tests according to AEP-STANAG 4569 were carried out for the total composite armour systems. After the ballistic tests, AA2024-CNT3 showed the best protection results, compared with the other plates(AA2024-CNT1 and AA2024-CNT2), with the projectile being unable to fully penetrate the composite plate.

关键词： Passive armour protection Protective armour Ballistic performance Hybrid composites Vehicle protection

Genotype-based precision nutrition strategies for the prediction and clinical management of type 2 diabetes mellitus

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World Journal of Diabetes 2024年第2期15卷 142-153页

作者： omar Ramos-Lopez medicine and Psychology School Autonomous University of Baja CaliforniaTijuana 22390Baja CaliforniaMexico

Globally,type 2 diabetes mellitus(T2Dm)is one of the most common metabolic disorders.T2Dm physiopathology is influenced by complex interrelationships between genetic,metabolic and lifestyle factors(including diet),which differ between populations and geographic *** fact,excessive consumptions of high fat/high sugar foods generally increase the risk of developing T2Dm,whereas habitual intakes of plant-based healthy diets usually exert a protective ***,genomic studies have allowed the characterization of sequence DNA variants across the human genome,some of which may affect gene expression and protein functions relevant for glucose *** comprehensive literature review covers the impact of gene-diet interactions on T2Dm susceptibility and disease progression,some of which have demonstrated a value as biomarkers of personal responses to certain nutritional ***,novel genotype-based dietary strategies have been developed for improving T2Dm control in comparison to general lifestyle ***,progresses in other omics areas(epigenomics,metagenomics,proteomics,and metabolomics)are improving current understanding of genetic insights in T2Dm clinical *** more investigation is still needed,the analysis of the genetic make-up may help to decipher new paradigms in the pathophysiology of T2Dm as well as offer further opportunities to personalize the screening,prevention,diagnosis,management,and prognosis of T2Dm through precision nutrition.

关键词： Type 2 diabetes mellitus Nutrigenetics Single nucleotide polymorphism Genotype Diet Precision nutrition

Control and vibration analyses of a sandwich doubly curved micro-composite shell with honeycomb,truss,and corrugated cores based on the fourth-order shear deformation theory

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Applied mathematics and mechanics(English Edition) 2024年第10期45卷 1773-1790页

作者： f.SHIRDELAN m.mOHAmmADImEHR f.BARGOZINI Department of Solid mechanics Faculty of Mechanical EngineeringUniversity of KashanKashan 87317-53153Iran

Curved shells are increasingly utilized in applied engineering due to their shared characteristics with other sandwich structures,flexibility,and attractive ***,the inability of controlling and regulating vibrations and destroying them afterward is a challenge to *** this paper,the curve shell equations and a linear quadratic regulator are adopted for the state feedback design to manage the structure vibrations in state space forms.A five-layer sandwich doubly curved micro-composite shell,comprising two piezoelectric layers for the sensor and actuator,is modeled by the fourth-order shear deformation *** core(honeycomb,truss,and corrugated)is analyzed for the bearing of transverse shear *** results show that the honeycomb core has a greater effect on the *** the parameters related to the core and the weight percentage of graphene increase,the frequency *** uniform distribution of graphene platelets results in the lowest natural frequency while the natural frequency ***,without taking into account the piezoelectric layers,the third-order shear deformation theory(TSDT)and fourth-order shear deformation theory(fOSDT)align ***,when the piezoelectric layers are incorporated,these two theories diverge significantly,with the frequencies in the fOSDT being lower than those in the TSDT.

关键词： vibration and control doubly curved shell micro-composite honeycomb truss corrugate core

Cervical Cancer Prediction Empowered with federated machine Learning

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Computers, materials & Continua 2024年第4期79卷 963-981页

作者： muhammad Umar Nasir omar Kassem Khalil Karamath Ateeq Bassam SaleemAllah Almogadwy m.A.Khan Khan muhammad Adnan Department of Computer Sciences Bahria University Lahore CampusLahore54000Pakistan faculty of Information Technology Liwa CollegeAbu Dhabi20009UAE Department of Computing Skyline University CollegeSharjah999041UAE Department of Computer Science Taibah UniversityMedina42315Saudi Arabia Riphah School of Computing and Innovation Faculty of ComputingRiphah International UniversityLahore54000Pakistan Department of Software Faculty of Artificial Intelligence and SoftwareGachon UniversitySeongnam13120Korea

Cervical cancer is an intrusive cancer that imitates various women around the world. Cervical cancer ranks in thefourth position because of the leading death cause in its premature stages. The cervix which is the lower end of thevagina that connects the uterus and vagina forms a cancerous tumor very slowly. This pre-mature cancerous tumorin the cervix is deadly if it cannot be detected in the early stages. So, in this delineated study, the proposed approachuses federated machine learning with numerous machine learning solvers for the prediction of cervical cancer totrain the weights with varying neurons empowered fuzzed techniques to align the neurons, Internet of medicalThings (IomT) to fetch data and blockchain technology for data privacy and models protection from hazardousattacks. The proposed approach achieves the highest cervical cancer prediction accuracy of 99.26% and a 0.74%misprediction rate. So, the proposed approach shows the best prediction results of cervical cancer in its early stageswith the help of patient clinical records, and all medical professionals will get beneficial diagnosing approachesfrom this study and detect cervical cancer in its early stages which reduce the overall death ratio of women due tocervical cancer.

关键词： Cervical cancer federated machine learning neurons blockchain technology

DNBP-CCA:A Novel Approach to Enhancing Heterogeneous Data Traffic and Reliable Data Transmission for Body Area Network

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Computers, materials & Continua 2024年第5期79卷 2851-2878页

作者： Abdulwadood Alawadhi mohd.Hasbullah omar Abdullah Almogahed Noradila Nordin Salman A.Alqahtani Atif m.Alamri InterNetWorks Research Laboratory School of ComputingUniversiti Utara MalaysiaSintok06010Malaysia faculty of Computer Science and Information Technology Universiti Tun Hussein Onn MalaysiaParit RajaJohor86400Malaysia School of Games&Creative Technology University for the Creative ArtsFarnhamGU97DSUK Computer Engineering Department College of Computer and Information SciencesKing Saud UniversityRiyadh11543Saudi Arabia Software Engineering Department College of Computer and Information SciencesKing Saud UniversityRiyadh11543Saudi Arabia

The increased adoption of Internet of medical Things (IomT) technologies has resulted in the widespread use ofBody Area Networks (BANs) in medical and non-medical domains. However, the performance of IEEE 802.15.4-based BANs is impacted by challenges related to heterogeneous data traffic requirements among nodes, includingcontention during finite backoff periods, association delays, and traffic channel access through clear channelassessment (CCA) algorithms. These challenges lead to increased packet collisions, queuing delays, retransmissions,and the neglect of critical traffic, thereby hindering performance indicators such as throughput, packet deliveryratio, packet drop rate, and packet delay. Therefore, we propose Dynamic Next Backoff Period and Clear ChannelAssessment (DNBP-CCA) schemes to address these issues. The DNBP-CCA schemes leverage a combination ofthe Dynamic Next Backoff Period (DNBP) scheme and the Dynamic Next Clear Channel Assessment (DNCCA)scheme. The DNBP scheme employs a fuzzy Takagi, Sugeno, and Kang (TSK) model’s inference system toquantitatively analyze backoff exponent, channel clearance, collision ratio, and data rate as input parameters. Onthe other hand, the DNCCA scheme dynamically adapts the CCA process based on requested data transmission tothe coordinator, considering input parameters such as buffer status ratio and acknowledgement ratio. As a result,simulations demonstrate that our proposed schemes are better than some existing representative approaches andenhance data transmission, reduce node collisions, improve average throughput, and packet delivery ratio, anddecrease average packet drop rate and packet delay.

关键词： Internet of medical Things body area networks backoff period tsk fuzzy model clear channel assessment media access control