检索结果-南通市图书馆

Optimal Feedback Control of Nonlinear Variable-Speed Marine Current Turbine Using a Two-Mass Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2020年第1期19卷 83-95页

作者： Rajae Gaamouche Abdelbari Redouane imad el harraki Bouchra Belhorma Abdennebi el Hasnaoui electromechanics Department Mohammadia School of Engineering10000 RabatMorocco electromechanics Department National Superior School of Mines10000 RabatMorocco National Centre for Energy Sciences and Nuclear Techniques 10000 RabatMorocco

This paper presents a contribution related to the control of nonlinear variable-speed marine current turbine(MCT)without pitch operating below the rated marine current *** that the operation of the MCT can be divided into several operating zones on the basis of the marine current speed,the system control objectives are different for each *** deal with this issue,we develop a new control approach based on a linear quadratic regulator with variable generator *** proposed approach enables the optimization of the rotational speed of the turbine,which maximizes the power extracted by the MCT and minimizes the transient loads on the *** novelty of our study is the use of a real profile of marine current speed from the northern coasts of *** simulation results obtained using MATLAB Simulink indicate the effectiveness and robustness of the proposed control approach on the electrical and mechanical parameters with the variations of marine current speed.

关键词： Marine current turbine Two-mass model Tip speed ratio Linearization Optimal control Linear quadratic regulator(LQR)

A novel CMOS charge-pump circuit with current mode control 110mA at 2.7V for telecommunication systems

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2010年第4期31卷 57-61页

作者： Salahddine Krit Hassan Qjidaa imad el Affar Yafrah Khadija Ziani Messghati Yassir el-Ghzizal Faculty of Sciences Dhar el Mehraz Laboratory of ElectronicSignal-Systymes and Informatic(LESSI)FesMorocco

This paper presents a novel organization of switch capacitor charge pump circuits based on voltage doubler structures. Each voltage doubler takes a DC input and outputs a doubled DC voltage. By cascading voltage doublers the output voltage increases up to 2 times. A two-phase voltage doubler and a multiphase voltage doubler structures are discussed and design considerations are presented. A simulator working in the Q-V realm was used for simplified circuit level simulation. In order to evaluate the power delivered by a charge pump, a resistive load is attached to the output of the charge pump and an equivalent capacitance is evaluated. To avoid the short circuit during switching, a clock pair generator is used to achieve multi-phase non-overlapping clock pairs. This paper also identifies optimum loading conditions for different configurations of the charge pumps. The proposed charge-pump circuit is designed and simulated by SPICE with TSMC 0.35-μm CMOS technology and operates with a 2.7 to 3.6 V supply voltage. It has an area of 0.4 mm^2; it was designed with a frequency regulation of 1 MHz and internal current mode to reduce power consumption.

关键词： switch capacitor charge pump voltage doubler power consumption

Two-point compression ultrasonography: Enough to rule out lower extremity deep venous thrombosis?

在线全文

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2021年第4期12卷 268-273页

作者： Ralphe Bou Chebl Nader el Souki Mirabelle Geha imad Majzoub Rima Kaddoura Hady Zgheib Department of Emergency Medicine American University of BeirutBeirut 11072020Lebanon

BACKGROUND: Deep venous thrombosis(DVT) is a major cause of morbidity and is a common presenting complaint to the emergency department(ED). Point-of-care two-point compression ultrasonography has evolved as a quick and effective way of diagnosing DVT. The purpose of this study is to validate the prevalence and distribution of venous thrombi isolated to proximal lower extremity veins, other than common femoral and popliteal veins in patients with ***: This is a single-center retrospective study that looked at patients presenting to the ED of a tertiary care hospital between January 2014 and August 2018. The clinical presentation and laboratory and imaging results were obtained using the hospital's electronic medical ***: A total of 2,507 patients underwent a lower extremity duplex ultrasound during the study period. Among them, 379(15%) were included in the study. The percentages of isolated thrombi to the femoral vein and deep femoral vein were 7.92% and 0.53%, respectively. When the patients were stratified into the two groups of isolated DVT and two-point compression DVT, there were no statistically significant differences in the laboratory results between both groups. However, immobilized patients and patients with recent surgeries were more likely to have an isolated ***: Thrombi isolated to proximal lower extremity veins other than the common femoral and popliteal veins make up 8.45% of DVTs. Given this significant number of missed DVTs, the authors recommend the addition of the femoral and deep femoral veins to the two-point compression exam.

关键词： Lower extremity Deep venous thrombosis Emergency department Two-point compression ultrasonography

Effect of Feature Selection on the Prediction of Direct Normal Irradiance

在线全文

学校读者我要写书评

暂无评论

Big Data Mining and Analytics 2022年第4期5卷 309-317页

作者： Mohamed Khalifa Boutahir Yousef Farhaoui Mourade Azrour imad Zeroual Ahmad el Allaoui Faculty of Sciences and Techniques Moulay Ismail UniversityErrachidia 52000Morocco

Solar radiation is capable of producing heat,causing chemical reactions,or generating ***,the amount of solar radiation at different times of the day must be determined to design and equip all solar ***,it is necessary to have a thorough understanding of different solar radiation components,such as Direct Normal Irradiance(DNI),Diffuse Horizontal Irradiance(DHI),and Global Horizontal Irradiance(GHI).Unfortunately,measurements of solar radiation are not easily accessible for the majority of regions on the *** paper aims to develop a set of deep learning models through feature importance algorithms to predict the DNI *** proposed models are based on historical data of meteorological parameters and solar radiation properties in a specific location of the region of Errachidia,Morocco,from January 1,2017,to December 31,2019,with an interval of 60 *** findings demonstrated that feature selection approaches play a crucial role in forecasting of solar radiation accurately when compared with the available data.

关键词： machine learning deep learning feature importance renewable energies solar radiation

Epidemiology of type 2 diabetes in the Middle East and North Africa:Challenges and call for action

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Diabetes 2021年第9期12卷 1401-1425页

作者： imad M el-Kebbi Nayda H Bidikian Layal Hneiny Mona Philippe Nasrallah Department of Internal Medicine Division of EndocrinologyAmerican University of Beirut Medical CenterFaculty of MedicineBeirut 11072020Lebanon Department of Internal Medicine Sheikh Shakhbout Medical CityAbou Dhabi 11001United Arab Emirates School of Medicine American University of BeirutFaculty of MedicineBeirut 11072020Lebanon University Libraries Saab Medical LibraryAmerican University of BeirutBeirut 11072020Lebanon

Type 2 diabetes continues to be a serious and highly prevalent public health problem *** 2019,the highest prevalence of diabetes in the world at 12.2%,with its associated morbidity and mortality,was found in the Middle East and North Africa *** addition to a genetic predisposition in its population,evidence suggests that obesity,physical inactivity,urbanization,and poor nutritional habits have contributed to the high prevalence of diabetes and prediabetes in the *** risk factors have also led to an earlier onset of type 2 diabetes among children and adolescents,negatively affecting the productive years of the youth and their quality of ***,efforts to control the rising prevalence of diabetes and its complications have been challenged and complicated by the political instability and armed conflict in some countries of the region and the recent coronavirus disease *** strategies,coupled with targeted interventions at the regional,national,and community levels are needed to address and curb the spread of this public health crisis.

关键词： Type 2 diabetes Middle East and North Africa Epidemiology Prevalence Prediabetes Complications

Role of urine studies in asymptomatic febrile neutropenic patients presenting to the emergency department

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2021年第2期12卷 99-104页

作者： Hady Zgheib Aline el Zakhem Cynthia Wakil Mohamad Ali Cheaito Rola Cheaito Antoine Finianos Ralphe Bou Chebl Rima Kaddoura Nader Al Souky imad el Majzoub Department of Emergency Medicine American University of Beirut Medical CenterBeirut 11-0236Lebanon Department of Internal Medicine American University of Beirut Medical CenterBeirut 11-0236Lebanon

BACKGROUND: The role of urine studies in the detection of urinary tract infection(UTI) in febrile neutropenic patients with urinary symptoms(having a urinary catheter or having a positive urine analysis) is inarguable. However, the evidence is scarce regarding the indication for urine studies in asymptomatic(i.e., without urinary symptoms) patients with febrile neutropenia(FN) presenting to the emergency department(ED). The aim of this study is to evaluate the need for obtaining urine studies in asymptomatic febrile neutropenic ***: This was a retrospective cohort study conducted on adult cancer patients who presented to the ED with FN and had no urinary symptoms. We included all ED presentations of eligible patients between January 2013 and September 2018. Student's t-test and Wilcoxon rank-sum test were used for continuous data, while Chi-square and Fisher's exact tests were used for categorical data. Participants were divided into two groups based on their urine culture(UC) results: negative and positive UCs. Two cut-offs were used for positive UC results: ≥10~5 cfu/m L and ≥10~4 cfu/m ***: We included 284 patients in our study. The age of our patient population was 48.5±18.5 years. More than two-thirds(68.7%) of patients had severe neutropenia, while only 3.9% and 9.9% of the patients had positive UCs at ≥10~5 cfu/m L and ≥10~4 cfu/m L, respectively. UCs were expectedly positive in most patients with urinalysis(UA) abnormalities. However, 27.3% and 32.1% of patients with positive UCs at ≥10~5 cfu/m L and ≥10~4 cfu/m L respectively had a normal UA. CONCLUSIONS: In our study, the incidence of UTI in adult febrile neutropenic cancer patients who present to the ED without urinary symptoms is low. Consequently, routine urine testing may not be warranted in this population, as it adds unnecessary financial burdens on the patients and delays timely management.

关键词： Adult Cancer Emergency department Febrile neutropenia Urine testing

Screening of biological activities of Polygonum maritimum *** A lgerian coast

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2013年第8期3卷 611-616页

作者： imad Abdelhamid el-Haci Fawzia Atik Bekkara Wissame Mazari Fay al Hassani Mohamed AmineDidi Laboratoire des Produits Naturels BP 119 Imama13000Université Abou Bekr Belkaid-Tlemcen-Algérie Laboratoire d'Ecologie et Gestion des Ecosystèmes Naturels BP 119 Imama13000Université Abou Bekr Belkaid-Tlemcen-Algérie Laboratoire des Technologies de Séparations et de Purifications BP 119 Imama13000Université Abou Bekr Belkaid-Tlemcen-Algérie

Objective:To investigate the antioxidant and the antibacterial activities of crude extract from aerial part of Polygonum maritimumL.(Polygonaceae)(***)and to find new actives ***:The whole plant was collected from the Rechgoune coast(West of Algeria),and methanolic crude extract of aerial parts ***(PMCE)was *** extract was tested against different bacterial strain and tested for his ability to neutralize free radical(DPPH)and to scavenge the ***:PMCE had a very high content of total phenol,which was(352.49依18.03)mg/g dry weight,expressed as gallic acid *** exhibited excellent antioxidant activity,as measured using DPPH and H2O2 scavenging *** also showed a high antibacterial activity against gram-positive bacterial strains:Bacillus cereus,Bacillus subtilisandStaphylococcus aureus with an highest MIC of 120μg/***:The antioxidant and antibacterial activity of the PMCE is probably due to phenolic compounds present in the *** contemporary presence of antioxidant and antibacterialactivities in the PMCE suggests that this plant may be a source of bioactive substances with multifaceted activity.

关键词： Polygonum maritimumL. Phenolic compounds Antioxidant activity Antibacterial activity

Dynamic evaluation of jack-up platform structure under wave, wind, earthquake and tsunami loads

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean Engineering and Science 2022年第1期7卷 41-57页

作者： Zaid Mohammed Ghazi imad Shakir Abbood Farzad Hejazi Department of Civil Engineering Universiti Putra MalaysiaMalaysia Engineering Affairs Department Sunni Endowment DiwanBaghdadIraq

Nowadays,the demand for using jack-up platforms to carry out a large percentage of deep-water oil and gas exploration is steadily *** response of jack-up platforms to the severe dynamic loads that may be encountered during the structure life is not examined ***,this study attempts to investigate the response of jack-up platforms performance under the effect of dynamic loads due to wave,wind,earthquake and tsunami forces using the finite element method for two models with the lowest and highest hull *** jack-up platform is located in the Gulf of *** ac-celerations are applied to the model in high and moderate seismic *** addition,tsunami waves are applied to the platform in three different directions at 0°,45°and 90°.This study utilised Airy’s linear wave approach to assess the surface elevations and wave *** reference wind velocity is 10 knots at 10 m over the mean water *** indicate that the dynamic response of the structure is affected by the height of the platform and by the increase of the platform hull *** combination of the el-Centro earthquake,dead and live loads provides the major impact on the platform at the lowest(70 m)and highest(85 m)hull *** comparison of all result proves that the jack-up platform hull under high earthquake intensity and tsunami waves with 45°has experienced maximum ***,raising the deck will increase the response of the dynamic load and displacements but will negatively affect the platform.

关键词： Offshore structures Earthquake Dynamic excitation Jack-up platform Tsunami Seismic zone

The Buccal Lid Approach for Removal of Impacted Mandibular Molars—When, How and Why?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Stomatology 2017年第1期7卷 81-90页

作者： Fares Kablan Victoria Yaffe imad Abu el-Naaj Department of Oral and Maxillofacial Surgery Baruch Padeh Medical Center Poriya Israel Department of Oral and Maxillofacial Surgery Baruch Padeh Medical Center Affiliated to the Faculty of Medicine of Bar-Ilan University in the Galilee Poriya Israel

Background: The surgical removal of impacted mandibular molars represents one of the most prevalent procedures carried out by the oral and maxillofacial surgeon. Despite its prevalence, unusual impaction location of mandibular molars necessitates alternative extraction approaches. One of the methods described for extraction of deeply impacted molars is the bony lid approach which was first presented for surgical endodontic treatment of mandibular molars. The aim of this study was to evaluate the outcome of the bony lid approach in extracting mandibular molars. In addition, critical clinical key points, new aspects while performing this procedure, indications and contraindications are discussed. Materials and Methods: 9 patients were treated with the bony lid technique. A retrospective analysis of medical charts was conducted to evaluate the results of surgery. Results: The operative technique described in the article was successfully carried out in 12 cases of impacted mandibular molars. No incidence of permanent sensory deficit was recorded. In one patient, an infection mandated the removal of the bony lids. In all other cases the healing process was uneventful. Conclusion: The bony lid technique has many advantages over alternative extraction methods and should be considered as a treatment option in cases of critical proximity between an impacted tooth and the inferior alveolar nerve.

关键词： Buccal Lid Mandibular Molars Extraction