检索结果-南通市图书馆

Pollution of water resources due to industrialization in arid zone of rajasthan, india

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2001年第2期13卷 218-223页

作者： m A khan Central Arid Zone research institute Jodhpur-342003 India.

in arid zone of rajasthan, india, nearly 21,900 hm2 area along Bandi river has been affected by industrial effluent discharge into the river bed. Analysis of groundwater samples collected from these sites revealed that area at the vicinity of the river is most affected. The effluent water in the river is the main source of contamination of ground water. Concentration of sodium and chloride has been higher with proportional increase in TDS and EC value in the area within zone A (river water), zone B (0-100 m), zone C (101-250 m), zone D (251-500 m) and zone E (501-1000 m). There is decreasing trend in ion concentration from zone A to zone E and F, reflecting reduced effect of effluents. The pollution of water resources has resulted in the degradation of other natural resources such as land, soil and vegetation. Nearly 4463 hm2 (20.38%) area has been very severely affected. EC value at places exceeds 20 dS/m. Soil and land have become hard, compact and saline. Cropping intensity has declined. in the area (3633 hm2) affected severely, the EC value of water varies from 10-20 dS/m. irrigation with such water has created problem of salinity, sodicity in soils. Herbal biomass declined considerably. Double cropping has almost stopped. Almost 8494 hm2 area is affected moderately. EC of ground water varies from 5 to 10 dS/m. Fragile surface crust, declining trend of phosphorous and potassium in the soil, poor density of natural vegetation are significant manifestations. Apart from this, 5305 hm2 area is slightly affected.

关键词： india Pollution of water resources due to industrialization in arid zone of rajasthan

Performance evaluation of minimum quantity lubrication by vege-table oil in terms of cutting force,cutting zone temperature,tool wear,job dimension and surface finish in turning AiSi-1060 steel

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1790-1799页

作者： khan m.m.A. DHAr N.r. Department of industrial and Production Engineering Shahajalal University of Science and Technology Sylhet 3114 Bangladesh Department of industrial and Production Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka Bangladesh

in all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication (mQL) has been suggested since a decade ago as a means of addressing the issues of environmental intru- siveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of mQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AiSi-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by mQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.

关键词： minimum quantity lubrication (mQL) Cutting force Chip-tool interface temperature Tool wear Surface roughness Dimensional deviation

Exploring the enigmatic interplay between polymers and nanoparticles in a non-Newtonian viscoelastic fluid

在线全文

学校读者我要写书评

暂无评论

CHiNESE JOUrNAL OF CHEmiCAL ENGiNEEriNG 2024年第11期75卷 161-169页

作者： khan, r. Alameer, A. Afraz, m. Ahmad, A. Nawaz, r. khan, Y. Univ Campania Luigi Vanvitelli Dipartimento Matemat & Fis I-81100 Caserta Italy Univ Hafr Al Batin Dept Math Hafar al Batin 31991 Saudi Arabia COmSATS Univ islamabad Dept Math Islamabad 44000 Pakistan Gulf Univ Sci & Technol Ctr Appl Math & Bioinformat CAMB Hawally 32093 Kuwait

Non-Newtonian fluids have variable viscosity in response to shear rate, and the presence of polymers and nanoparticles further modifies their flow characteristics. in this paper, the effects of polymers and nanoparticles on mass and heat transfer control, drag reduction, boundary layer flow development in a polymeric finitely extensible nonlinear elastic-Peterlin (FENE-P) fluid, and the significance of nanoscience in modern day life are discussed. We examine the behavior of polymer additives by utilizing a dispersion model in conjunction with the polymeric FENE-P model. Our work includes a comparison with Cortell's earlier work, which only looked at the behavior of polymer's inclusion into the base fluid. This research investigates numerically how the inclusion of polymers and nanoparticles into the base fluid reduces drag while increasing heat and mass transfer. The observed variations in skin friction, reduced Nusselt, and Sherwood numbers indicate an intriguing correlation between the rates of heat and mass transport and surface drag. more precisely, as the heat and mass transfer efficiency improve, the surface encounters less resistance, which is commonly referred to as drag. in summary, the research highlights the capability of polymers and nanoparticles to effectively modify fluid dynamics, minimize drag, and enhance mass and heat transfer inside the flow region. (c) 2024 The Chemical industry and Engineering Society of China, and Chemical industry Press Co., Ltd. All rights are reserved, including those for text and data mining, Ai training, and similar technologies.

关键词： Polymers FENE-P model Nanofluids radiative heat flux Flow and heat transfer Numerical solution

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

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Nitriding of Aluminium Alloy in Nitrogen and Nitrogen-Helium mixture Using 100 Hz-Pulsed DC Glow Discharge

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2010年第4期12卷 452-460页

作者： Nasrullah khan m.SHOAiB SHAH r.AHmAD Department of Physics GC University

Nitriding of aluminium alloy （***0.8） in nitrogen and nitrogen-helium mixture was carried out by using 100 Hz-pulsed DC glow discharge. Samples are treated for different durations, namely 4 h, 8 h and 12 h, in nitrogen plasma as well as in a mixture of nitrogen- helium plasma for the same processing duration of 4 h. All nitriding treatments are carried out at an input power of 100 W, filling pressure of 1 mbar and substrates temperature of 250~C. X-ray diffraction （XrD） results show an expansion in lattice spacing and consequently shift of diffraction peaks towards lower angle with the addition of helium in nitrogen plasma. Surface morphology of the treated sample is investigated by scanning electron microscopy （SEm） and energy dispersive X-ray analysis （EDX）. Vickers micro-hardness testing results show increases in surface hardness with processing duration as well as with the addition of helium in nitrogen plasmas. This increase of surface hardness may be attributed to the diffusion of nitrogen content in the surface layer generating internal stresses. it is observed that the addition of helium positively affects the nitriding of samples.

关键词： nitrogen-helium mixture plasma nitriding X-ray diffraction surface hardness

role of ion Beam irradiation and Annealing Efect on the Deposition of AlON Nanolayers by Using Plasma Focus Device

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2013年第11期15卷 1127-1135页

作者： i.A.khan r.S.rAWAT r.VErmA G.mACHArAGA r.AHmAD Z.A.UmAr m.A.K.SHAHiD Department of Physics Government College University38000 Faisalabad Pakistan National institute of Education Nanyang Technological UniversitySingapore 637616Singapore Department of Physics GC University54000 Lahore Pakistan

AlON nanolayers are synthesized on Al substrate by the irradiation of energetic nitrogen ions using plasma focusing. Samples are exposed to multiple （5, 10, 15, 20 and 25） focus shots. ion energy and ion number density range from 80 keV to 1.4 meV and 5.6×10^19 m^- 3 to 1.3×10^19 m ^-3, respectively. moreover, the effect of continuous annealing （473 K and 523 K） on an AlN surface layer synthesized with 25 focus shots is also examined. The main features of the X-ray diffraction （XrD） patterns with increasing focus shots are：（i） variation in the crystallinity of AlN along （111）, （200） and （311） planes, （ii） increasing average crystallite size of AlN （111） plane, and （iii） stress relaxation observed in AlN （111） and （200） planes. The crystallinity of AlN surface layer is comparatively better at 473 K annealing temperature. A broadened diffraction peak related to an aluminium oxide phase showing weak crystallinity is observed for 15 focus shots while non-bounded oxides are present in all other deposited layers. raman and Fourier transform infrared spectroscopy （FTir） analysis confirm the presence of AlN and Al203 for the surface layer annealed at 473 K temperature. raman analysis shows that the overlapping of AlN and Al2Oa results in the development of residual stresses. Scanning electron microscope （SEm） results demonstrate that the formation of rounded grains （range from 20 nm to 200 nm） and variations in their microstructures features depend on the increasing number of focus shots. Decomposition of larger clusters into smaller ones is observed.

关键词： characterization XrD focus shots X-ray diffraction nucleation surface layer

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

在线全文

学校读者我要写书评

暂无评论

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

Phase analysis of AlFe2B2 by synchrotron X-ray diffraction,magnetic and m?ssbauer studies

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:materials international 2017年第2期27卷 251-256页

作者： Tahir Ali m.N.khan E.Ahmed Asad Ali Physics Division Pakistan Institute of Nuclear Science and technology Department of Physics Abdul Wali khan University PiNSAT Preston University

The structural and magnetic properties of essentially phase pure AlFe2B2prepared by arc melting were compared with a sample containing impurities. Analysis was carried out by means of synchrotron X-ray diffraction, magnetic measurements and m?ssbauer spectroscopy. The analysis of synchrotron X-ray diffraction data confirmed the orthorhombic structure of space group Cmmm for AlFe2B2with Al13Fe4as main impurity phase. The magnetic measurements revealed an unsaturated ferromagnetic state in AlFe2B2with a transition temperature（Tc） of 286 K. isothermal magnetization measurment at 5 K gave a saturation magnetization of 0.7 μB per Fe atom while Arrott plots establish the second order nature of ferromagnetic transition. The thermal evolution of m?ssbauer spectra confirmed the ferromagnetic nature of this material revealing an hyperfine field of 73 kOe and an isomer shift of 0.46 mm/s at 100 K. The m?ssbauer spectra of a phase pure sample was compared with the one containing impurity phases. it is suggested that the low temperature paramagnetic contribution in m?ssbauer spectra of phase pure material may have its origin in some intrinsic phenomena arising from defects or inhomogeneities in crystal structure.

关键词： AlFe2B2 Synchrotron X-ray diffraction Ferromagnetism mossbauer effect spectroscopy

investigation of generalized Fick's and Fourier's laws in the second-grade fluid flow

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2018年第11期39卷 1617-1630页

作者： T.HAYAT S.AHmAD m.i.khan A.ALSAEDi Department of mathematics Quaid-i-Azam University Nonlinear Analysis and Applied mathematics (NAAm) research Group Department of Mathematics Faculty of Science King Abdulaziz University

The second-grade fluid flow due to a rotating porous stretchable disk is modeled and analyzed. A porous medium is characterized by the Darcy relation. The heat and mass transport are characterized through Cattaneo-Christov double *** thermal and solutal stratifications at the surface are also accounted. The relevant nonlinear ordinary differential systems after using appropriate transformations are solved for the solutions with the homotopy analysis method(HAm). The effects of various involved variables on the temperature, velocity, concentration, skin friction, mass transfer rate, and heat transfer rate are discussed through graphs. From the obtained results,decreasing tendencies for the radial, axial, and tangential velocities are observed. Temperature is a decreasing function of the reynolds number, thermal relaxation parameter,and Prandtl number. moreover, the mass diffusivity decreases with the Schmidt number.

关键词： second-grade liquid thermal and solutal stratification Cattaneo-Christov double diffusion rotating stretchable disk