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Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.safi m.VAKILIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

mATHEmATICAL ANALYSIS OF WEST NILE VIRUS mODEL WITH DISCRETE DELAYS

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Acta mathematica Scientia 2013年第5期33卷 1439-1462页

作者： Salisu m.GARBA mohammad A.safi Department of mathematics and Applied mathematics University of Pretoria Department of mathematics The Hashemite University

The paper presents the basic model for the transmission dynamics of West Nile virus （WNV）. The model, which consists of seven mutually-exclusive compartments representing the birds and vector dynamics, has a locally-asymptotically stable disease- free equilibrium whenever the associated reproduction number （R0） is less than unity. As reveal in [3, 20], the analyses of the model show the existence of the phenomenon of backward bifurcation （where the stable disease-free equilibrium of the model co-exists with a stable endemic equilibrium when the reproduction number of the disease is less than unity）. It is shown, that the backward bifurcation phenomenon can be removed by substituting the associated standard incidence function with a mass action incidence. Analysis of the reproduction number of the model shows that, the disease will persist, whenever R0 〉 1, and increase in the length of incubation period can help reduce WNV burden in the community if a certain threshold quantities, denoted by △b and △v are negative. On the other hand, increasing the length of the incubation period increases disease burden if △b 〉 0 and △v 〉 0. Furthermore, it is shown that adding time delay to the corresponding autonomous model with standard incidence （considered in [2]） does not alter the qualitative dynamics of the autonomous ：system （with respect to the elimination or persistence of the disease）.

关键词： West Nile virus (WNV) equilibria stability persistent reproduction number

Nonlinear Vibration Analysis of Functionally GradedNanobeam Using Homotopy Perturbation method

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Advances in Applied mathematics and mechanics 2017年第1期9卷 144-156页

作者： majid Ghadiri mohsen safi Faculty of Engineering Department of MechanicsImam Khomeini International UniversityQazvinIran

In this paper, He’s homotopy perturbation method is utilized to obtainthe analytical solution for the nonlinear natural frequency of functionally gradednanobeam. The functionally graded nanobeam is modeled using the Eringen’s nonlocalelasticity theory based on Euler-Bernoulli beam theory with von Karman nonlinearityrelation. The boundary conditions of problem are considered with both sidessimply supported and simply supported-clamped. The Galerkin’s method is utilizedto decrease the nonlinear partial differential equation to a nonlinear second-order ordinarydifferential equation. Based on numerical results, homotopy perturbationmethodconvergence is illustrated. According to obtained results, it is seen that the second termof the homotopy perturbation method gives extremely precise solution.

关键词： Homotopy perturbation method Lindstedt-Poincare method analytical solution nonlocal nonlinear free vibration functionally graded nanobeam

Ambiguity Resolution in Direction of Arrival Estimation with Linear Antenna Arrays Using Differential Geometry

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Computers, materials & Continua 2022年第1期70卷 581-599页

作者： Alamgir safi muhammad Asghar Khan Fahad Algarni muhammad Adnan Aziz m.Irfan Uddin Insaf Ullah Tanweer Ahmad Cheema Department of Electronic Engineering ISRA UniversityIslamabad44000Pakistan Hamdard Institute of Engineering&Technology Islamabad44000Pakistan College of Computing and Information Technology University of BishaBishaSaudi Arabia Institute of Computing Kohat University of Science and TechnologyKohatPakistan

Linear antenna arrays(LAs)can be used to accurately predict the direction of arrival(DOAs)of various targets of interest in a given ***,under certain conditions,LA suffers from the problem of ambiguities among the angles of targets,which may result inmisinterpretation of such *** order to cope up with such ambiguities,various techniques have been ***,none of them fully resolved such a problem because of rank deficiency and high computational *** aimed to resolve such a problem by proposing an algorithm using differential *** proposed algorithm uses a specially designed doublet antenna array,which is made up of two individual linear *** angle observation models,ambiguous observation model(AOm)and estimated observation model(EOm),are derived for each individual *** ambiguous set of angles is contained in the AOm,which is obtained from the corresponding array elements using differential *** EOm for each array,on the other hand,contains estimated angles of all sources impinging signals on each array,as calculated by a direction-finding algorithm such as the genetic *** algorithm then contrasts the EOm of each array with its AOm,selecting the output of that array whose EOm has the minimum correlation with its corresponding *** comparison to existing techniques,the proposed algorithm improves estimation accuracy and has greater precision in antenna aperture selection,resulting in improved resolution capabilities and the potential to be used more widely in practical *** simulation results using mATLAB authenticates the effectiveness of the proposed algorithm.

关键词： Antenna array direction of arrival ambiguity resolution doublet antenna array ambiguous observation model estimated observation model

Evaluation of rainwater harvesting and shrub establishment methods for sustainable watershed management in northern Afghanistan

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Journal of mountain Science 2022年第8期19卷 2346-2359页

作者： LOUHAICHI mounir HASSAN Sawsan GAmOUN mouldi safi Navin ABDALLAH mohamed A.B. ATES Serkan International Center for Agricultural Research in the Dry Areas(ICARDA) Tunis 1004Tunisia Department of Animal and Rangeland Sciences Oregon State UniversityCorvallisOR 97331USA International Center for Agricultural Research in the Dry Areas(ICARDA) Amman 11185Jordan Consultant-Field Assistant Mazar Sharif 1703Afghanistan

Watershed rangelands in Northern Afghanistan provide various ecosystem services that support the local people's livelihoods,but they are now highly degraded essentially due to the continuous high grazing pressure and recurrent *** of shrub establishment method enhanced by water harvesting techniques to rehabilitate degraded rangelands have not been well *** main goal of this study was to evaluate the impact of direct seeding and transplanting of seedlings in combination with semi-circular bunds on growth,yield,and survival rate of four shrub species(Atriplex halimus,Atriplex nummularia,Atriplex lentiformis,andmaireana brevifolia)under semi-arid conditions of Sayyad village,Khulm *** rate(%),plant height,width,and plant length(cm)and plant cover(%)were measured for each plant over five occasions.A non-destructive reference unit was used to estimate biomass *** results showed that growth attributes and biomass production of shrubs were consistently greater in the transplanting compared to direct *** average,the plant length,width,height,volume,cover,and biomass production of transplanted shrubs were greater than direct-seeded shrubs by 24.3%,8.6%,8.7%,121.5%,13.8% and 34.1%,*** production of transplanted seedlings was the highest for ***(1313.5 g Dm/plant)and ***(800 g Dm/plant).There was a strong correlation between plant biomass production and plant volume(R^(2)_(Plant volume)=0.88)for the shrub ***,indicating that plant volume is a key variable for assessing biomass production for this ***,the survival rate of *** was 100% in both planting methods,suggesting that based on better survival this halophytic plant has great potential when restoring degraded ***,on the basis of better growth rates,yield,and survival,transplanting *** *** may enhance shrub establishment and contribute to the rehabilitation of slop

关键词： Biomass production Land degradation Rangeland rehabilitation Seed germination Shrub survival Vegetation cover Water harvesting

Particle Size Distribution and Hydraulic Conductivity in Coastal Non-Agricultural Land in Gaza Coastal Plain

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International Journal of Geosciences 2018年第10期9卷 619-633页

作者： Jamal safi Yasser El-Nahhal mohamed safi Environmental Protection and Research Institute (EPRI) Gaza Palestine Al-Azhar University Gaza Palestine TheIslamic University of Gaza Gaza Palestine

Background: Particle size distribution and hydraulic conductivity of coastal no-agricultural lands are not available. This study characterized the particle size distribution and hydraulic conductivity on coastal non-agricultural land along the coastal plain of Gaza. materials and methods: Six soil profiles were digged along the coastal plain in Gaza Strip and soil samples were collected from 0 - 150 cm depth. Four soil plots around each site were used to determine the hydraulic conductivity using Infiltrometer method. Four particle size groups were identified, group 1 (630 nm), group 2 (200 nm), group 3 (63 nm) and group 4 (20 nm). Results: Dominancy of particle size group 2 was noticed in all sites followed by group 3. Groups 1 and 4 were less dominant in all sites. Hydraulic conductivity ranged from lower value 0.27 in the control soil plot in Khan Younis (site 1) to the highest value 1.76 m/s in disturbed soil plot in Shakhejjlen (site 3) with regression coefficient (R2) range of 0.9725 - 0.997 indicating strong positive association. Conclusion: It can be concluded that the coastal non-agricultural land is sandy with various hydraulic conductivity values due to different particle size distribution. These data are useful to the scientific community around the world and will be helpful to speculate potential risk factors to life of ecosystem.

关键词： Particle Size Hydraulic Conductivity Soil Disturbance Coastal Land Soil Profile Ecosystem

Governance of noncommunicable diseases in Afghanistan

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Chronic Diseases and Translational medicine 2024年第3期10卷 238-246页

作者： Narges Neyazi Ali m.mosadeghrad maryam Tajvar Najibullah safi International Campus School of Public HealthTehran University of Medical SciencesTehranIran Department of Health System Development World Health OrganizationAfghanistan Department of Health management Policy and EconomicsSchool of Public HealthTehran University of Medical SciencesTehranIran

Background Noncommunicable diseases(NCDs)are the main reasons of mortality *** of every two person is dying due to NCDs in *** policy actors,mainly the World Health Organization(WHO),published several reports and declarations on controlling and preventing *** study aimed to provide a situation for governance of NCDs in Afghanistan and proper solutions for identified *** We conducted qualitative research utilizing interpretive phenomenology.A self-developed questionnaire was developed to conduct the semi-structured interviews with 39 experts from *** results were analyzed using a deductive framework *** building block framework of health system developed by the WHO was used as predefined framework for this *** The governance building block of health system consists of five subthemes including policy making,planning,organizing,stewardship,and *** identified main strengths,weaknesses,opportunities,and challenges for these *** experts also provided key recommendations to address the *** management of NCDs is a neglected part of the health system in *** evidence-based policy making with technical and indigenous planning,establishing responsive units with adequate financial and human resources within different ministries to address“health in all policies”concept,passing and implementing national laws and regulations to support national strategies for prevention and control of NCDs,and establishing decentralized monitoring systems to control the implementation of these strategies are the main recommendations of this *** government and international policy actors should invest and support the development of a multisectoral coordination system at national level for Afghanistan.

关键词： governance health in all policies health system multisectoral coordination noncommunicable diseases

Assessing moroccan physician knowledge and practices regarding maternal obesity's impact on childhood obesity:Implications for prevention and intervention

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World Journal of Clinical Pediatrics 2024年第2期13卷 146-160页

作者： Imane Douiyeh Jihane Khamlich Naima Nabih Asmae Saih Ilham Boumendil Anas Regragui Anass Kettani Amal safi Laboratory Biochemistry Environment and Agri-food Department of BiologyFaculty of Science and Technics MohammediaHassanⅡUniversity CasablancaMohammedia 28806Morocco Department of Biology Faculty of Sciences Ben M’Sik HassanⅡUniversity of CasablancaCasablanca 20000Morocco Department of medical ACHAS Association of the Doctors Ain Chock Casablanca MoroccoCasablanca 20400Morocco Department of medical HassanⅡUniversityCasablanca 20400Morocco

BACKGROUND Childhood obesity is a growing global concern with far-reaching health *** study focuses on evaluating the knowledge and practices of physicians in morocco regarding the link between maternal obesity and childhood *** the increasing prevalence of childhood obesity worldwide,this issue remains inadequately addressed in the moroccan *** To assess the awareness and practices of physicians in morocco concerning the connection between maternal obesity and childhood *** The research encompasses a comprehensive survey of practicing physicians,revealing significant gaps in awareness and practices related to maternal *** Notably,a significant portion of doctors do not provide adequate guidance to overweight pregnant women,highlighting the urgency for targeted educational *** In conclusion,this research illuminates critical areas for improvement in tackling childhood obesity in *** addressing these gaps,fostering awareness,and enhancing medical practices,the healthcare system can contribute significantly to preventing childhood obesity and improving the overall health of future generations.

关键词： Childhood obesity maternal obesity management Prevention Screening

Comparative Life Cycle Assessment of Two Types of Truck Bumper Produced in the Algerian Auto Industry

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Journal of Resources and Ecology 2020年第4期11卷 378-387页

作者： KEBBOUCHE Zahia TAIRI Abdelaziz safi Brahim Department of Chemical and Pharmaceutical Processes Engineering Faculty of Hydrocarbons and ChemistryUniversity M’hamed Bougara of BoumerdesBoumerdes 35000Algeria Department of Engineering Process Faculty of Engineering SciencesUniversity M’hamed Bougara of BoumerdesBoumerdes 35000Algeria

Currently,the reduction of weight in automotive is a very important topic to reduce the air *** this context,the purpose of the present paper is to analyze a real case study through a comparison of the environmental impacts between a conventional steel bumper and a polyester *** the first part of this work,a door-to-door life-cycle assessment methodology was used throughout the study of the component manufacturing *** SimaPro 7.1 software is used to evaluate the impacts of both bumpers on the environment and *** second part is devoted to dust analysis from the polyester *** obtained results have allowed us to show the company that its choice of steel substitution by the polyester is advantageous for certain impacts including the impact of climate change,but unfortunately there may be,given the working conditions of the polyester workshop,a transfer of impact,since we will end up with a risk of health(irritations,cancers)for the *** has proven to be a very useful tool for validating a redesigned automotive component from an environmental point of view;from this case study,several recommendations were made for the company to design environmentally friendly components,and ecodesign should be introduced into the company’s procedures.

关键词： eco-design SimaPro 7.1 life cycle analysis automotive industry Eco-indicator 99