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High Voltage 2020年第6期5卷 731-738页

作者： L.Loiselle u.Mohan Rao i.Fofana Research Chair on the Aging of Power Network infrastructure(ViAHT) Universitédu QuébecàChicoutimiChicoutimiQCG7H 2B1Canada

in this work, mineral oil and synthetic esters were selected at different ageing factors (based on acidity values). Fresh and aged oils have been subjected to high-energy discharges (repeated 100 breakdowns) to simulate electric faults of highly vulnerable intensity. The intent of this work is to understand the influence of high-energy electric faults on oil degradation and gassing tendency at different ageing conditions. in this study, the influence of the high-energy discharges on degradation and gassing tendency at different ageing factors is reported for mineral oil and synthetic esters. Oil degradation is reported by adopting ultraviolet spectroscopy, turbidity and particle counter as per american society for testing and materials (ASTM) standard test methods. Gassing tendencies and fault gas analysis are understood by dissolved the gas analysis using Duval's triangle and Duval's pentagon methods for mineral and non-mineral oils. it is found that the influence of high-energy discharges on oil degradation is higher in mineral oils to that of the synthetic esters. The intensity of the gassing tendency is higher for ester fluids;however, as per the Duval methods, the faulty conditions are at lower levels as compared to mineral oils.

关键词： synthetic energy high

Experimental study on the microstructural and anti-corrosion behaviour of Co-deposition Ni-Co-SiO_2 composite coating on mild steel

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Defence Technology（防务技术） 2018年第1期14卷 64-69页

作者： C.u.Atuanya D.i.Ekweghiariri C.M.Obele Department of Metallurgical and Materials Engineering Nnamdi Azikiwe UniversityAwkaAnambra StateNigeria Department of Polymer and Textile Engineering Nnamdi Azikiwe UniversityAwkaAnambra StateNigeria

Mild steel is commonly used in the construction of Pipeline. The major problem of this Pipeline is corrosion. Effort is make my researchers to combat this problem. in this work Co-deposition of Ni-CoSiO_2 composite coating on mild steel was reported with the view to reduce this problem. The SiO_2 was varies from 5 to 25 wt% in the deposition. The microstructure, hardness values and potentiodynamic polarization in simulated sea water were determined. The results show that XRD pattern of the Ni Co deposited mild steel revealed the presence hard phases of NiO, Co_5Ni, Co_2Ni_3, Ni Co5 while that of Ni-CoSiO_2 deposited mild steel revealed the presence harder phases of NiOSiO_2, CoNi_7Si_2, Co_5Ni_2Si_3. The NiCo-25 SiO_2 deposited sample has smaller particle size than Ni-10 Co coating. Coating thickness of 110.7 mm was obtained for Ni-10 Co coating, while coating thickness of 135.7, 157.7, 165.0 mm were obtained at Ni-10 Co-x SiO_2(x=10, 15, 25 wt%). 99.90% corrosion resistance was achieved at Ni-Co-25 SiO_2. This improvement in corrosion resistance after composites coating could be attributed to the hard and fine structure obtained after coating.

关键词： Co-deposition Corrosion Microstructure and coating

Novel technique for measurement of coating layer thickness of fine and porous particles using focused ion beam

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Particuology 2019年第1期17卷 190-198页

作者： M. Goslinska i. Selmer C. Kleemann u.Kulozik i. Smirnova S. Heinrich Hamburg university of Technology Institute of Solids Process Engineering and Particle TechnologyDenickestr1521073 HamburgGermany Hamburg university of Technology Institute of Thermal Separation ProcessesEiJ^endorfer Str. 3821073 HamburgGermany Technical university of Munich Chair of Food and Bioprocess EngineeringWeihenstephaner Berg 185354 FreisingGermany

A novel technique for the measurement of the coating layer thickness of fine particles was developed in this work based on cross-sectioning of micrometre-sized single coated particles using focused ion beam (FiB) milling. This technique was tested on two batches of aerogel particles coated with thin coatings in a spouted bed. The FiB milling procedure consisted of two steps. First, the desired part of the coated particle was removed using a high ion beam current. The resulting cross-sectioned area was then polished using a lower ion beam current to make the cross-section clearly visible. The FiB milling process was controlled with simultaneous scanning electron microscopy (SEM). Afterwards, the coating layer thickness was evaluated using the SEM images. The coating layer was successfully applied on the porous aerogel microparticles in the spouted bed. The coating uniformity of the highly porous particles increased with increasing sprayed coating solution amount, with up to 91% of the particle pores being covered. The FiB-cross-sectioning technique using an ion beam of 2.50 nA for the first milling and 0.43 nA for polishing of the surface resulted in successful generation of cross-sections of representative particles with a visible particle core and coating layer. A coating layer thickness of approximately 700 nm was achieved on particles with sizes of below 45 μm.

关键词： Coating layer thickness Focused ion beam Microparticle Aerogel Spouted bed Dilute spouting

Braids with Trivial Simple Centralizer

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Algebra Colloquium 2015年第4期22卷 561-566页

作者： u. Ali F. Azam i. Javaid A. Haider Center for Advanced Studies in Pure and Applied Mathematics Bahauddin Zakariya university Multan Pakistan Department of Mathematics Jazan University Jazan Saudi Arabia

in this paper, we prove that the n-simple braid divisible by the generators xi for all 2 ≤ i ≤n - 2 has trivial simple centralizer. Consequently, the commuting graph defined on the set of simple braids is disconnect... 详细信息

关键词： simple braid simple centralizer commuting graph

Control strategies of avian influenza pandemic model with time delay

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international Journal of Biomathematics 2017年第7期10卷 219-236页

作者： u. Roman Z. Gul i. Saeed u. Hakeem S. Shafie Department of Mathematics Bacha Khan University Charsadda Khyber Pakhtunkhwa Pakistan Department of Mathematics University of Malakand Chakdara Dir(Lower) Khyber Pakhtunkhwa Pakistan Department of Mathematics Abdul Wali Khan University Mardan Khyber Pakhtunkhwa Pakistan Department of Mathematical Sciences universiti Teknologi Johor Bahru Malaysia

A mathematical model for avian influenza with optimal control strategies is presented as a system of discrete time delay differential equations （DDEs） and its important math-ematical features are analyzed. in alignment to manage this, we develop an optimally controlled pandemic model of avian influenza and insert a time delay with exponential factor. Then we apply two controlled functions in the form of biosecurity of poultry and the education campaign against avian influenza to control the disperse of the dis- ease. Our optimal control strategies will minimize the number of contaminated humans and contaminated birds. We also derive the basic reproduction number to examine the dynamical behavior of the model and demonstrate the existence of the controlled system. For the justification of Our work, we present numerical simulations.

关键词： Time-delay optimal control existence numerical simulation

Magnetic properties of Sn-substituted Ni-Zn ferrites synthesized from nano-sized powders of NiO, ZnO, Fe2O3, and SnO2

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Chinese Physics B 2017年第7期26卷 377-382页

作者： M A Ali M M uddin M N i Khan F u Z Chowdhury S M Hoque S i Liba Department of Physics Chittagong University of Engineering and Technology (CUET) Materials Science Division Atomic Energy Center

A series of Ni0.6-x/2Zn0.4-x/2SnxFe2O4(x = 0.0, 0.05, 0.1, 0.15, 0.2, and 0.3)(NZSFO) ferrite composities have been synthesized from nano powders using a standard solid state reaction technique. The spinel cubic structure of the investigated samples has been confirmed by x-ray diffraction(XRD). The magnetic properties such as saturation magnetization(Ms),remanent magnetization(Mr), coercive field(Hc), and Bohr magneton(μ) are calculated from the hysteresis loops. The value of Msis found to decrease with increasing Sn content in the samples. This change is successfully explained by the variation of A-B interaction strength due to Sn substitution in different sites. The compositional stability and quality of the prepared ferrite composites have also been endorsed by the fairly constant initial permeability(μ’) over a wide range of frequency. The decreasing trend of μ’ with increasing Sn content has been observed. Curie temperature TChas been found to increase with the increase in Sn content. A wide spread frequency utility zone indicates that the NZSFO can be considered as a good candidate for use in broadband pulse transformers and wide band read-write heads for video recording. The composition of x = 0.05 shows unusual results and the possible reason is also mentioned with the established formalism.

关键词： magnetic properties saturation magnetization permeability Curie temperature

Peripheral blood lymphocytes DNA in patients with chronic liver diseases

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World Journal of Gastroenterology 2001年第2期7卷 235-237页

作者： Vasiliy i Reshetnyak Tatyana i Sharafanova Ludmila u ilchenko Elena V Golovanova Gennadiy G Poroshenko Central Research institute of Gastroenterology MoscowRussia

BACKGROuND: Viral replication in blood cells with nucleases may lead to the damage of lymphocytes genetic apparatus and the beginning of immunopathological reactions. AiM: Of this investigation is to reveal the damage to peripheral blood lymphocytes (PBL) DNA in the patients with chronic liver diseases. MATERiALS AND METHODS: Sixteen-nine patients with chronic liver diseases (37 patients with chronic viral hepatitis, 2 patients with liver cirrhosis of mixed etiology (alcohol+virus G), 30 women with primary biliary cirrhosis-PBC) were examined. The condition of DNA structure of PBL was measured by the fluorescence analysis of DNA unwinding (FADu) technique with modification. Changes of fluorescence (in %) reflected the DNA distractions degree (the presence of DNA single-stranded breaks and alkalinelabile sights). RESuLTS AND CONCLuSiON: The quantity of DNA single-stranded breaks and alkalinelabile sights in DNA in all patients with chronic viral hepatitis didn't differ from the control group, excluding the patients with chronic hepatitis (CH) C+G. Patients with HGV and TTV monoinfection had demonstrated the increase of the DNA single-stranded breaks PBL quantity. This fact may be connected with hypothesis about the viruses replication in white blood cells discussed in the literature. Tendency to increase quantity of DNA PBL damages in the patients with primary biliary cirrhosis (PBC) accordingly to the alkaline phosphatase activity increase was revealed. Significant decrease of the DNA single-stranded breaks and alkalinelabile sights in the PBC patients that were treated with prednisone was demonstrated. Probably, the tendency to increase the quantity of DNA single stranded breaks and alkalinelabile sights in lymphocytes of the PBC patients was depended on the surplus of the blood bile acid content.

关键词： DNA Damage Adolescent Adult Aged Alkaline Phosphatase Chronic Disease Female Hepatitis, Chronic Hepatitis, Viral, Human Humans Leukocytes, Mononuclear Liver Cirrhosis Liver Cirrhosis, Biliary Liver Diseases Male Middle Aged Research Support, Non-u.S. Gov't

Stability analysis and modeling for the three-dimensional Darcy-Forchheimer stagnation point nanofluid flow towards a moving surface

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Applied Mathematics and Mechanics(English Edition) 2021年第3期42卷 357-370页

作者： Yuming CHu M.i.KHAN M.i.u.REHMAN S.KADRY S.QAYYuM M.WAQAS Department of Mathematics Huzhou UniversityHuzhou 313000Zhejiang ProvinceChina Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering Changsha University of Science&TechnologyChangsha 410114China Department of Mathematics Riphah International UniversityFaisalabad CampusFaisalabad 38000Pakistan Department of Mathematics Quaid-i-Azam UniversityIslamabad 44000Pakistan Department of Mathematics and Computer Science Beirut Arab UniversityBeirut 11072809Lebanon NuTECH School of Applied Sciences and Humanities National University of TechnologyIslamabad 44000Pakistan

in this research,the three-dimensional(3D)steady and incompressible laminar Homann stagnation point nanofluid flow over a porous moving surface is *** disturbance in the porous medium has been characterized by the Darcy-Forchheimer *** slip for viscous fluid is *** energy equation is organized in view of radiative heat flux which plays an important role in the heat transfer *** governing flow expressions are first altered into first-order ordinary ones and then solved numerically by the shooting *** solutions are obtained for the velocity,skin friction coefficient,temperature,and Nusselt number subject to sundry flow parameters,magnetic parameter,Darcy-Forchheimer number,thermal radiation parameter,suction parameter,and dimensionless slip *** this research,the main consideration is given to the engineering interest like skin friction coefficient(velocity gradient or surface drag force)and Nusselt number(temperature gradient or heat transfer rate)and discussed numerically through *** conclusion,it is noticed from the stability results that the upper branch solution(uBS)is more reliable and physically stable than the lower branch solution(LBS).

关键词： viscous slip Darcy-Forchheimer relation thermal radiation stagnation point flow dual solution heat generation/absorption stability result

New Bi-metallic Single Source Precursors for the Deposition of Thin Films of Semiconductor Ceramics

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Journal of Materials Science & Technology 2007年第2期23卷 196-200页

作者： u.Salma M.Mazhar J.i.Akhter Z.Ali Department of Chemistry Quaid-i-Azam UniversityIslamabad 45320Pakistan Physics Division Pakistan Institute of Nuclear Science and TechnologyP.O.NiloreIslamabadPakistan

Stable binary single source precursors （SSP） for the deposition of thin films of ceramic semiconductors of composition SnO·GeO were synthesized by close circuit chemical vapour deposition （CCCVD） method. Elemental analysis and spectroscopic techniques were used to characterize the precursors. Scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） were employed to characterize the thin films. Resistivity measurements were conducted to show that the films are of semiconducting nature.

关键词： Single source precursors CCCVD Organotin carboxylates

Effects of heavy metals (Pb^(2+) and Cd^(2+)) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803

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Chinese Journal of Oceanology and Limnology 2009年第2期27卷 383-388页

作者： K. K. i. u. Arunakumara 张学成 College of Marine Life Sciences Ocean University of China Department of Crop Science Faculty of AgricultureUniversity of Ruhuna

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb^2＋ and Cd〉（0, 0.5, 1, 2, 4, 6 and 8 mg/L）. The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased （〉4 mg/L Pb^2＋） metal concentration. The photosynthetic apparatus （thylakoid membranes） were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. in addition, at the highest concentration （8 mg/L pb^2＋）, the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations （0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L pb^2＋）, both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents （chlorophyll a, 13 carotene and phycocyanin） were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb^2＋, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, 13 carotene and phycocyanin respectively over the control. Corresponding reductions for the same CdZ＋concentrations were 57.83, 48.94 and 56.90%. Lethal concentration （96 h LC50） values （3.47 mg/L Cd^2＋ and 12.11 mg/L Pb^2＋） indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd^2＋ than Pb^2＋.

关键词： growth pigment contents Synechocystis sp. PCC 6803 ultrastructure