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American Journal of Analytical Chemistry 2024年第7期15卷 219-228页

作者： Laila Abdullah Alshatti The public authority for applied education and training College of Nursing General Science Department Shwaikh B State of Kuwait

The new method proposed is based on the formation of hydralazine-Bromophenol blue ion pair simply and without further extraction or heating. The ion pair was prepared in the presence of pH 3 citrate buffer forming a yellow-colored chromogen. A new maximum UV-visible band formed at 416 nm. The color was stable for more than 10 hours and obeyed Beer’s Law over the concentration range of 10 - 50 µg/mL. The calculated molar absorptivity and Sandell’s sensitivity were 1.01 × 104 L∙mol−1∙cm−1 and 0.0514 µg/mL, respectively. The elements of method validation stipulated by The International Conference on Harmonization [Q2 (R1)] were applied for hydralazine hydrochloride assay in pure and pharmaceutical tablet formulation. The average recoveries of the pure solution and the pharmaceutical formulation were 98.94% and 99.50%, respectively. The results were statistically compared by F-test, which indicates that the method can be precise and repeatable for both pure and pharmaceutical solutions. The method was found to be accurate, reproducible, and cost-effective, and validated for the assay of hydralazine in terms of the routine quality control.

关键词： Spectrophotometry Validation Hydralazine Hydrochloride International Conference on Harmonization Q2 (R1)

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

Observer Based Control for a Class of Systems with Output Deadzone Nonlinearity

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Intelligent Control and Automation 2024年第3期15卷 95-107页

作者： Nizar J. Alkhateeb Hameed K. Ebraheem Department of Electronic Engineering Technology College of Technological Studies Public Authority of Applied Education and Training (PAAET) Kuwait City Kuwait

In this paper, a combination of model based adaptive design along with adaptive linear output feedback controller is used to compensate for robotic manipulator with output deadzone nonlinearity. The deadzone dynamics are utilized to adaptively estimate the deadzone parameter and a switching function is designed to eliminate the error produced in the adaptive observer dynamics. The overall design of the closed loop system ensures stability in the BIBO criterion.

关键词： Adaptive Output Observer Deadzone Compensation Robot Manipulator Sliding Mode Control

Utilization of Logistical Regression to the Modified Sine-Gordon Model in the MST Experiment

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Open Journal of Modelling and Simulation 2024年第2期12卷 43-58页

作者： Nizar J. Alkhateeb Hameed K. Ebraheem Eman M. Al-Otaibi Department of Electronic Engineering Technology College of Technological Studies (CTS) The Public Authority of Applied Education and Training (PAAET) Kuwait City Kuwait

In this paper, a logistical regression statistical analysis (LR) is presented for a set of variables used in experimental measurements in reversed field pinch (RFP) machines, commonly known as “slinky mode” (SM), observed to travel around the torus in Madison Symmetric Torus (MST). The LR analysis is used to utilize the modified Sine-Gordon dynamic equation model to predict with high confidence whether the slinky mode will lock or not lock when compared to the experimentally measured motion of the slinky mode. It is observed that under certain conditions, the slinky mode “locks” at or near the intersection of poloidal and/or toroidal gaps in MST. However, locked mode cease to travel around the torus;while unlocked mode keeps traveling without a change in the energy, making it hard to determine an exact set of conditions to predict locking/unlocking behaviour. The significant key model parameters determined by LR analysis are shown to improve the Sine-Gordon model’s ability to determine the locking/unlocking of magnetohydrodyamic (MHD) modes. The LR analysis of measured variables provides high confidence in anticipating locking versus unlocking of slinky mode proven by relational comparisons between simulations and the experimentally measured motion of the slinky mode in MST.

关键词： Madison Symmetric Torus (MST) Magnetohydrodyamic (MHD) Sine-Gordon Toroidal Dynamic Modelling Reversed Field Pinch (RFP) Logistical Regression

Depolarization Degree to Determine Dihedral Attribute of Radar Target

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Journal of Electromagnetic Analysis and Applications 2024年第6期16卷 85-101页

作者： Faisal Aldhubaib Electronics Department Faculty of Technological Studies Public Authority for Applied Education Shuwaikh Kuwait

This paper investigates the ability of the depolarization degree, derived from the characteristic polarization states at the resonant frequency set, to identify corner or swept, i.e. dihedral, changes in same-class targets by a metallic wire example. A well-estimated depolarization degree requires a robust extraction of the fundamental target resonance set in two orthogonal sets of fully co-polarized and cross-polarized polarization channels, then finding the null polarization states using the Lagrangian method. Such depolarization degree per resonance mode has the potential to form a robust feature set because it is relatively less sensitive to onset ambiguity, invariant to rotation, and could create a compact, recognizable, and separable distribution in the proposed feature space. The study was limited to two targets with two swept changes of fifteen degrees within normal incidence;under a supervised learning approach, the results showed that the identification rate converging to upper-bound (100%) for a signal-to-noise ratio above 20 dB and lower-bound around (50%) below −10 dB.

关键词： Polarimetry Radar Target Recognition Time-Domain Analysis Remote Sensing

Correlation of gut microorganisms and non-volatile flavor substances provides new insights for breeding Scylla paramamosain

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Journal of Oceanology and Limnology 2024年第4期42卷 1336-1347页

作者： Gao GAO Xing LI Kangxiang QIN Yun HU Xiaosong JIANG Chenxi CHE Yuntao LI Changkao MU Chunlin WANG Huan WANG School of Marine Science Ningbo UniversityNingbo 315211China Key Laboratory of applied Marine Biotechnology Ministry of EducationNingbo UniversityNingbo 315211China

The farming of Scylla paramamosain with specific flavors has a higher commercial value,and the flavors are related to the integrated farming environment and non-volatile flavor substances,while the survival environment is one of the important ways to source gut microorganisms in the *** this study,the levels of dominant taxa in the gut flora of *** from Mong Cai,Vietnam(VN),Taishan City,Guangdong Province(TS)of China,and Ninghai County,Ningbo City(NB)Zhejiang Province of China converged with those of *** from Sanmen County,Ningbo City(CK 1,CK 2,and CK 3)at 28 d of *** top 15 genera with the highest abundance of VN,TS,and NB gut flora were the same as CK 1,CK 2,and CK 3,but with different percentages,and gradually converged to CK 1,CK 2,and CK 3,respectively,at 28 d of *** between intestinal flora and non-volatile flavor substances in the hepatopancreas at the percentage level of relative abundance of bacterial genera found that above 28 d of domestication,Muribaculaceae,Psychrilyobacter,Clostridia_vadinBB 60_group,Halarcobacter Carboxylicivirga,Sediminispirochaeta may be the most important genera affecting flavor amino acids of ***,Carboxylicivirga,Halarcobacter,Photobacterium,ZOR 0006,Psychrilyobacter,and Pseudomonas may be the most important genera affecting flavor amino acids of ***,Carboxylicivirga,Halarcobacter,Photobacterium,ZOR 0006,Vibrio,and Sphingomonas may be the most important genera affecting flavor amino acids of *** results show that the intestinal flora structure of crabs from different areas were domesticated in the same area for at least 28 d before they converged to that of the domesticated crab,and the most important genera affecting the flavor amino acids of TS,VN,and NB were also *** results of this study provide a reference and basis for the technique of directional cultivation of the flavor quality of the crab.

关键词： survival environment Scylla paramamosain intestinal flora structure non-volatile flavor substance directional breeding

GLOBAL BOUND ON THE GRADIENT OF SOLUTIONS TO p-LAPLACE TYPE EQUATIONS WITH MIXED DATA

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Acta Mathematica Scientia 2024年第4期44卷 1394-1414页

作者： Minh-Phuong TRAN The-Quang TRAN Thanh-Nhan NGUYEN applied Analysis Research Group Faculty of Mathematics and StatisticsTon Duc Thang UniversityHo Chi Minh CityVietnam Nguyen Huu Huan High School Thu Duc CityVietnam Group of Analysis and applied Mathematics Department of MathematicsHo Chi Minh City University of EducationVietnam

In this paper,the study of gradient regularity for solutions of a class of elliptic problems of p-Laplace type is *** particular,we prove a global result concerning Lorentz-Morrey regularity of the non-homogeneous boundary data problem:-div((s^(2)+|▽u|^(2)p-2/2)▽u)=-div(|f|^(p-2)f)+g inΩ,u=h in■Ω,with the(sub-elliptic)degeneracy condition s∈[0,1]and with mixed data f∈L^(p)(Q;R^(n)),g∈Lp/(p-1)(Ω;R^(n))for p∈(1,n).This problem naturally arises in various applications such as dynamics of non-Newtonian fluid theory,electro-rheology,radiation of heat,plastic moulding and many *** on the idea of level-set inequality on fractional maximal distribution functions,it enables us to carry out a global regularity result of the solution via fractional maximal *** to the significance of M_(α)and its relation with Riesz potential,estimates via fractional maximal functions allow us to bound oscillations not only for solution but also its fractional derivatives of orderα.Our approach therefore has its own interest.

关键词： gradient estimates p-Laplace quasilinear elliptic equation fractional maximal operators Lorentz-Morrey spaces

Quasi-periodic variations of low energy cosmic rays

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Science China(Technological Sciences) 2016年第4期59卷 547-557页

作者： KUDELA Karel SABBAH Ismail IEP SAS Kosice Slovakia Department of Natural Sciences College of Health Sciencesthe Public Authority for Applied Education and TrainingKuwait

Cosmic rays(CR)play an important role in space weather-related *** temporal variability,both of a quasi-periodic character as well as an irregular one,has been studied from ground-based direct measurements,as well as from cosmogenic nuclides,over a long *** attempt to describe the current knowledge of selected quasi-periodicities in CR flux in the energy range above the atmospheric threshold,from direct *** power spectrum density(PSD)of the CR time series as measured by neutron monitors(NMs)and by muon detectors has a rather complicated *** with the shape(slope)of the PSD,knowledge of the contribution of quasi-periodic variations(q-per)to the CR signal is of importance for the modulation,as well as for checking the links of CR to space weather,and/or to space climate *** rotation of the Earth and solar rotation cause two types of mechanisms behind the certain q-per observed in secondary CR on the Earth’s *** activity and solar magnetic field cyclicities contribute to the q-per signals in CR if studied over a longer *** complexity of the spatial structure of the interplanetary magnetic field(IMF)and its evolution within the heliosphere,in addition to the changes in the geomagnetic field,cause variability in contributions of the q-per in *** spectra are useful tools for checking the fine structure of q-per and their temporal *** a long time NMs and muon telescopes provide information about q-per in CR.

关键词： cosmic rays periodicities neutron monitors muon detectors

Evaluating the Effectiveness of Consultants’ Roles in Improving Value for Money in public Infrastructure Projects in Ghana

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Journal of Building Construction and Planning Research 2024年第3期12卷 69-85页

作者： Sheitu Abu Nongiba Alkanam Kheni Adams Abudi Department of Technical and Vocational education Mampong Technical College of Education Mampong Ghana Department of Construction Akenten Appiah-Menka University of Skills Training and Entrepreneurial Development Kumasi Ghana Department of Technical and Vocational education Bagabaga Training College Tamale Ghana

Ghanaian construction projects encounter a number of challenges, including low health, safety, and environmental requirements, poor performance, and time and cost overruns. To provide value for money (VFM) on government infrastructure projects in Ghana, this research assesses the roles of project consultants, specifically architects and quantity surveyors, and highlights important obstacles. A cross-sectional survey design involving architects and quantity surveyors yielded a 96% response rate after 100 questionnaires were distributed. Consultants’ responsibilities also include monitoring standards compliance, providing advice on delays, controlling budgets, and advising on project completion dates. Difficulties encompass a lack of promptness in decision-making, unethical conduct, political pressure, and inadequate focus on contract administration and construction audits. Project urgency, longevity, political clout, timely decision-making, and team experience are important variables that impact VFM. Policy makers and construction management practitioners should take note of the implications for Ghana’s public infrastructure projects.

关键词： Consultants Value for Money Physical Infrastructure Ghana

Plant assemblage and diversity variation with human disturbances in coastal habitats of the western Arabian Gulf

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Journal of Arid Land 2016年第5期8卷 787-798页

作者： Raafat H ABD EL-WAHAB Botany Department Faculty of ScienceSuez Canal University Science Department Faculty of Basic EducationPublic Authority for Applied Education and Training

Knowledge about plant diversity along disturbance gradients is essential for conservation and management of fragmented coastal *** study examined the effects of human disturbance intensity in coastal habitats of Kuwait on diversity,composition,identity and assemblage of vascular plant *** survey data from 113 plots （5m×5m each） were randomly selected in 51 sites at coastal fragmented habitats at three levels of disturbance intensities （high,moderate and low） and were statistically *** results revealed that about 76% of the recorded species are considered threatened species in Kuwait,most of which are being lost in high disturbed *** led to the dominance of Zygophyllum qatarense,Cornulaca aucheri and Salsola imbricata,which are species of disturbance ***,total plant cover and species diversity were higher in moderate and low disturbed habitats than in high disturbed *** diversity between high and low disturbed habitats was higher than either between high and moderate,or between moderate and low disturbed *** analyses showed statistically significant differences in composition of plant assemblages,which indicate high beta diversity between the habitat *** urbanization and industrialization are among the most serious threats that contribute to declines in biological diversity and rapid fragmentation of coastal habitats in *** protective enclosures in the disturbed habitats,planting endangered and vulnerable species,and establishing a natural reserve at Nuwaiseeb are recommended conservation actions to avoid loss of the fragmented coastal habitats and to facilitate restoration of native plants.

关键词： plant diversity disturbance gradient threatened species habitat fragmentation coastal habitat salt marsh restoration