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Surgical Science 2017年第7期8卷 312-318页

作者： Abdullah Al-Busaidi Tariq Al-Shafei Huda Al-Moqbali Sara Al-Kindi Mohammed Al-Saadi Nadya Al-Busaidi Hani Al-Qadhi College of Medicine & Health Sciences Sultan Qaboos University Muscat Sultanate of Oman

The aim of the study was to review traumatic splenic injury following blunt abdominal trauma (BAT), during the period from January 2009 to January 2015 at SQUH. The data for this study was retrospectively collected. It included 768 patients admitted to SQUH general surgery department following BAT. 43 patients with splenic injury were identified (34 males, 9 females). The mean age of patients with splenic injury was 36.0 years (34.4 years for males, 42.1 years for females). The most common mechanism of injury was motor vehicle collision (90.7%). Grade I, II are the most common grades of splenic injury. Non-Omani patients accounted for (51.2%) and most of them were pedestrians at the time of trauma. Ribs fracture is the most common injury associated with splenic injury. 36 (83.7%) patients were managed conservatively and 7 (16.3%) patients were splenectomized. Angioembolization was done for 11 (30.6%) patients. Despite the small population of Oman, high incidence of motor vehicle collision (MVC) increases the incidence of splenic injury among young age group.

关键词： Spleen Splenic Injury Blunt Abdominal Trauma Motor Vehicle Collision

Experimental investigation of viscous oil-water-sand flow in horizontal pipes:Flow patterns and pressure gradient

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Petroleum 2024年第2期10卷 275-293页

作者： Tarek Ganat Petroleum and Chemical Engineering Department Sultan Qaboos University

Fluid production from unconsolidated reservoirs often leads in sand production,which poses a number of *** deposition in flowlines can result in significant pressure dips,pipe and facility damage,and obstructions that decrease *** research is needed to understand the movement and deposition of sand in oil-water-sand（O-W-S） *** article focuses on O-W-S flows in a 6-meter-long horizontal pipe with an inner diameter of 0.0381 *** study looks at the flow behavior of high viscosity oil-water（O-W）,water-sand（W-S）,and oil-water-sand（O-W-S） *** were carried out at 250 psig pressure in a laboratory flow test facility using various heavy synthetic oils（viscosities ranging from 3500 cP to 7500 cP at 25℃） and tap *** sand concentration varied from 1% to 10%,with an average sand particle diameter of 145 μm and material density of 2630 kg/*** cuts ranged from 0.0 to *** experimental results revealed a minor change in pressure gradient between（O-W） and（O-W-S） ***,increasing the sand concentration in（O-W-S） flow resulted in higher pressure *** reduction factor of pressure gradient indicated that the highest decrease in pressure drop occurred at higher superficial oil ***,a direct relationship was observed between the reduction factor and the decrease in water *** results also showed that the minimum required transportation velocity for sand slurry decreased with increasing superficial oil velocity,while the minimum transportation condition increased with higher sand *** comparison between the expected pressure gradient from Bannwart and McKibben et *** the actual experimental data demonstrated significant accuracy for the oil viscosities and superficial oil velocities used in the study.

关键词： Slurry velocity Flow pattern Pressure gradient High viscosity Minimum transport condition

Studying the effect of surfactant assisted low-salinity water flooding on clay-rich sandstones

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Petroleum 2024年第2期10卷 306-318页

作者： Saeed Khezerloo-ye Aghdam Alireza Kazemi Mohammad Ahmadi Department of Petroleum Engineering Amirkabir University of Technology (AUT) Department of Petroleum and Chemical Engineering College of Engineering Sultan Qaboos University

Sandstone reservoirs often contain clay particles that can cause damage and reduce permeability during low-salinity water flooding. In this study, the effect of surfactants on fine migration in clay-rich sandstones and its impact on oil recovery was ***, the impact of surfactants on interparticle forces in fine-matrix, fine-fine, and oil-matrix systems was modeled. The results showed that both CTAB(cetyltrimethyl ammonium bromide) and QS(quillaja saponin) cause EDL compaction, weakening the repulsive forces. However, SDS(sodium dodecyl sulfate)and TX(triton X-100) do not affect the EDL. Next, the effect of surfactants on IFT reduction and wettability alteration was experimentally investigated. All surfactants reduced IFT due to the surface excessive concentration mechanism. The wettability alteration experiment illustrated that although QS and CTAB compact EDL around oil and matrix particles leading to attraction force augmentation, they both alter wettability through adsorption on matrix and carboxylic groups present in crude oil, *** aqueous solutions were then injected into various clay-rich sandstone sanpacks, which resulted in increased oil recovery. However, the mechanisms leading to enhanced oil recovery variedby surfactant type. CTAB increased recovery by 10% through IFT reduction and wettability alteration, while SDS and TX increased recovery by 12% and 9%, respectively, through wettability alteration and extreme fine migration. In contrast, partial fine migration in the QS flooding experiment reached a recovery increase of 18%. Permeability trends through experiments were also recorded. During CTAB injection,permeability did not reduce, while QS aqueous solution reduced rock permeability to 5 m D. SDS and TX reduced the magnitude of permeability to 2 m *** conclusion, this study demonstrates that surfactants can effectively improve oil recovery in clay-rich sandstones by altering the interparticle forces, reducing IFT, a

关键词： Surfactant flooding Smart water Fine migration Recovery factor

Empirical Wavelet Transform Based Method for Identification and Analysis of Sub-synchronous Oscillation Modes Using PMU Data

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 34-40页

作者： Joice G.Philip Jaesung Jung Ahmet Onen the Department of Energy Systems Research Ajou UniversitySuwonSouth Korea the Department of Electrical and Electronic Engineering Abdullah Gul UniversityKayseri38080Turkey the Department of Electrical and Computer Engineering College of EngineeringSultan Qaboos UniversityAl-KhoudMuscatOman

This paper proposes an empirical wavelet transform(EWT)based method for identification and analysis of sub-synchronous oscillation(SSO)modes in the power system using phasor measurement unit(PMU)*** phasors from PMUs are preprocessed to check for the presence of *** the presence is established,the signal is decomposed using EWT and the parameters of the mono-components are estimated through Yoshida *** superiority of the proposed method is tested using test signals with known parameters and simulated using actual SSO signals from the Hami Power Grid in Northwest *** show the effectiveness of the proposed EWT-Yoshida method in detecting the SSO and estimating its parameters.

关键词： Empirical wavelet transform(EWT) sub-synchronous oscillation Prony-based method Yoshida algorithm variational mode decomposition phasor measurement unit(PMU)

Suppression and synchronization of chaos in uncertain time-delay physical system

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Applied Mathematics:A Journal of Chinese Universities 2024年第3期 416-437页

作者： Israr Ahmad Muhammad Shafiq Department of Preparatory Studies Centre University of Technology and Applied Sciences Department of Electrical and Computer Engineering Sultan Qaboos University

The mechanical horizontal platform (MHP) system exhibits a rich chaotic *** chaotic MHP system has applications in the earthquake and offshore industries. This article proposes a robust adaptive continuous control (RACC) algorithm. It investigates the control and synchronization of chaos in the uncertain MHP system with time-delay in the presence of unknown state-dependent and time-dependent disturbances. The closed-loop system contains most of the nonlinear terms that enhance the complexity of the dynamical system; it improves the efficiency of the closed-loop. The proposed RACC approach (a) accomplishes faster convergence of the perturbed state variables (synchronization errors) to the desired steady-state,(b) eradicates the effect of unknown state-dependent and time-dependent disturbances, and (c)suppresses undesirable chattering in the feedback control inputs. This paper describes a detailed closed-loop stability analysis based on the Lyapunov-Krasovskii functional theory and Lyapunov stability technique. It provides parameter adaptation laws that confirm the convergence of the uncertain parameters to some constant values. The computer simulation results endorse the theoretical findings and provide a comparative performance.

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A Comprehensive Review on Charging Topologies and Power Electronic Converter Solutions for Electric Vehicles

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 675-694页

作者： Abdelfatah Ali Hossam H.H.Mousa Mostafa F.Shaaban Maher A.Azzouz Ahmed S.A.Awad the Department of Electrical Engineering American University of Sharjah26666 SharjahUnited Arab Emirates the Department of Electrical Engineering South Valley University83523 QenaEgypt the Department of Electrical and Computer Engineering University of WindsorWindsorON N9B 3P4 Canada Electrical Engineering Department Qatar UniversityDoha 2713Qatar Department of Electrical and Computer Engineering Sultan Qaboos UniversityMuscat123Oman

Electric vehicles(EVs)are becoming more popular worldwide due to environmental concerns,fuel security,and price *** performance of EVs relies on the energy stored in their batteries,which can be charged using either AC(slow)or DC(fast)***,EVs can also be used as mobile power storage devices using vehicle-to-grid(V2G)*** electronic converters(PECs)have a constructive role in EV applications,both in charging EVs and in ***,this paper comprehensively investigates the state of the art of EV charging topologies and PEC solutions for EV *** examines PECs from the point of view of their classifications,configurations,control approaches,and future research prospects and their impacts on power *** can be classified into various topologies:DC-DC converters,AC-DC converters,DC-AC converters,and AC-AC *** address the limitations of traditional DC-DC converters such as switching losses,size,and high-electromagnetic interference(EMI),resonant converters and multiport converters are being used in high-voltage EV ***,power-train converters have been modified for high-efficiency and reliability in EV *** paper offers an overview of charging topologies,PECs,challenges with solutions,and future trends in the field of the EV charging station applications.

关键词： Charging station charging topology electric vehicle power electronic converter vehicle-to-grid

Assistive techniques and their added value for tremor classification in multiple sclerosis

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Neural Regeneration Research 2024年第5期19卷 977-978页

作者： Nabin Koirala Abdulnasir Hossen Ioannis U.Isaias Jens Volkmann Muthuraman Muthuraman Child Study Center School of MedicineYale UniversityNew HavenCTUSA Department of Electrical&Computer Engineering Sultan Qaboos UniversityAl-KhodMuscatOman Neural Engineering with Signal Analytics and Artificial Intelligence Department of NeurologyUniversity Hospital of WürzburgWürzburgGermany Centro Parkinson e Parkinsonism Azienda Socio Sanitaria Territoriale G.Pini-CTO20126 MilanItaly

Tremor occurs in about half of multiple sclerosis(MS)*** tremor has a broad frequency range of 2.5-7 Hz,with a higher prevalence of postural tremor(44%)compared to intentional tremor(6%)(Alusi et al.,2001).Tremor may affect the upper and lower extremities,head,and trunk,and may even affect the vocal cords in isolated cases of palatal *** tremor is classically attributed to lesions of the brain stem,cerebellum,or cerebellar peduncles,and tremor intensity has been shown to correlate with the number of lesions or their functional ***,recent work has demonstrated that inflammatory damage to the cerebello-thalamic and cortico-thalamic pathways might also play an important role in causing tremor,as it co-occurs with other signs and symptoms of MS such as dysarthria,dysmetria,dysdiadochokinesia,and dystonia(Alusi et al.,2001).

关键词： tremor sclerosis

Modelling of debris-flow susceptibility and propagation: a case study from Northwest Himalaya

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Journal of Mountain Science 2024年第1期21卷 200-217页

作者： Hamza DAUD Javed Iqbal TANOLI Sardar Muhammad ASIF Muhammad QASIM Muhammad ALI Junaid KHAN Zahid Imran BHATTI Ishtiaq Ahmad Khan JADOON Badong National Observation and Research Station of Geohazards China University of GeosciencesWuhan 430074China Department of Earth Sciences COMSATS University IslamabadAbbottabad Campus 22010Pakistan Department of Earth Sciences Sultan Qaboos UniversityAl-KhoudMascat 123Oman Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China Department of Earth Sciences Abbottabad University of Science and TechnologyHavelian 22500Pakistan

The geological and geographical position of the Northwest Himalayas makes it a vulnerable area for mass movements particularly landslides and debris flows. Mass movements have had a substantial impact on the study area which is extending along Karakorum Highway(KKH) from Besham to Chilas. Intense seismicity, deep gorges, steep terrain and extreme climatic events trigger multiple mountain hazards along the KKH, among which debris flow is recognized as the most destructive geohazard. This study aims to prepare a field-based debris flow inventory map at a regional scale along a 200 km stretch from Besham to Chilas. A total of 117 debris flows were identified in the field, and subsequently, a point-based debris-flow inventory and catchment delineation were performed through Arc GIS analysis. Regional scale debris flow susceptibility and propagation maps were prepared using Weighted Overlay Method(WOM) and Flow-R technique sequentially. Predisposing factors include slope, slope aspect, elevation, Topographic Roughness Index(TRI), Topographic Wetness Index(TWI), stream buffer, distance to faults, lithology rainfall, curvature, and collapsed material layer. The dataset was randomly divided into training data(75%) and validation data(25%). Results were validated through the Receiver Operator Characteristics(ROC) curve. Results show that Area Under the Curve(AUC) using WOM model is 79.2%. Flow-R propagation of debris flow shows that the 13.15%, 22.94%, and 63.91% areas are very high, high, and low susceptible to debris flow respectively. The propagation predicated by Flow-R validates the naturally occurring debris flow propagation as observed in the field surveys. The output of this research will provide valuable input to the decision makers for the site selection, designing of the prevention system, and for the protection of current infrastructure.

关键词： North Pakistan Debris flow Flow-R Propagation Susceptibility mapping Debris-flow inventory Weighted Overlay Method

Delayed Grafting as a Valid Technique in Burn Management: Experience from a Burn Unit in Oman

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Modern Plastic Surgery 2024年第1期14卷 9-14页

作者： Taif Alsafy Joe Jacob Anish Thadathil Elias Ahmed Salah El Din Salim Mohammed Ghawas Majid Tariq Saud Albusaidi Ahmed Al Jabri Al Anood Al Hadhrami Mutazz Obeid Al Khaldi Moath Abdelhamid Shummo Karim Mohamed Haridi Aml Eid Saleh Said Al-Busaidi Department of Plastic and Reconstructive Surgery Sultan Qaboos Hospital Salalah Oman ENT Department Al Nahdha Hospital Muscat Oman Department of Plastic Reconstructive and Craniofacial Surgery Khoula Hospital Muscat Oman

Background: Early excision and grafting has been the preferred method of managing major burns around the world since 1970. Considering the advances in health care and the development of new antibiotics over the past 50 years, delayed grafting as a technique for the management of burns over 15%-20% of total body surface area (TBSA) could have comparable results to that of early excision. This study aims to highlight the outcomes of practicing delayed grafting in burn patients. Methods: A case series analysis was performed of 51 patients who were admitted to the burns unit in sultan qaboos hospital Salalah with over 20% TBSA between January 2014 and December 2019. The patients received prophylactic antibiotics and silver sulphadiazine dressing until the burn eschar had completely separated, followed by grafting. Results: Two patients were lost during the entire duration of the study. The mortality rate was comparable to that of early excision, while the rate of hypertrophic scarring was lower than the range reported by other studies. Conclusion: In the management of patients with over 20% TBSA, delayed grafting after complete separation of eschar is still a valid technique.

关键词： Burns Burn Units Burn Management Delayed Grafting Major Burns Treatment Efficacy

The impact of being in the COVID-19 pandemic on in-hospital mortality of non-infected patients aged 80 years and older with ST-elevation myocardial ınfarction

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Journal of Geriatric Cardiology 2024年第7期21卷 768-774页

作者： Mustafa Ebik Muhammet Gürdoğan UğurÖzkan Department of Cardiology Edirne Sultan 1.Murat State HospitalEdirneTurkey Department of Cardiology School of MedicineTrakya UniversityEdirneTurkey

The COVID-19 outbreak in late 2019 was declared a pandemic by the World Health Organization(WHO)on March 12,2020.[1]As of the latest WHO data,COVID-19 has caused over 770 million cases and nearly 7 million deaths worldwide.[2]hospitalizations due to COVID-19 are correlated with advanced age.[3,4]According to re-ports,individuals over the age of 65 account for 80%of COVID-19-related deaths.[3,4]This is primar-ily due to the increased burden of comorbidity with age.

关键词： infected patients mortality