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Synthesis of ZrSiN composite films using a plasma focus device

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Chinese Physics B 2014年第6期23卷 381-386页

作者： r.ahmad T.Hussain I.A.Khan r.S.rawat Center for Advanced Studies in Physics GC University Physics Department GC Universit National Institute of Education Nanyang Technological University

ZrSiN thin films are synthesized by using plasma focus through various numbers of focus shots （10, 20, and 30）, with samples placed at 9 cm away from the tip of the anode. Crystal structures, surface morphologies, and elemental compositions of ZrSiN films are characterized by an X-ray diffractometer （XrD） and scanning electron microscope （SEM） attached with energy dispersive X-ray spectroscopy （EDS）. XrD patterns confirm the formations of polycrystalline ZrSiN films. Crystallinity of nitride increases with the increase of focus shot number. The average crystallite size of zirconium nitride increases from 27 ± 3 nm to 73±8 nm and microstrain decreases from 2.28 to 1.0 with the increase of the focus shot number. SEM results exhibit the formations of granular and oval-shaped microstructures, depending on the number of focus shots. EDS results confirm the presences of silicon, zirconium, nitrogen, and oxygen in the composite films. The content values of Zr and N in the composite films increase with the increase of the focus shot number.

关键词： DPF ZrSiN thin films XrD SEM

Crop diagnostic system:A robust disease detection and management system for leafy green crops grown in an aquaponics facility

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Artificial Intelligence in Agriculture 2023年第4期10卷 1-12页

作者： r.Abbasi P.Martinez r.ahmad Aquaponics 4.0 Learning Factory(AllFactory) Department of Mechanical EngineeringUniversity of Alberta9211116 St.EdmontonAB T6G 2G8Canada Mechanical and Construction Engineering Department Northumbria UniversityNewcastle Upon Tyne NE77YTUK

Crops grown on aquaponics farms are susceptible to various diseases or biotic stresses during their growth cycle,just like traditional *** early detection of diseases is crucial to witnessing the efficiency and progress of the aquaponics *** combines recirculating aquaculture and soilless hydroponics methods and promises to ensure food security,reduce water scarcity,and eliminate carbon *** the large-scale imple-mentation of this farming technique,a unified system is needed that can detect crop diseases and support re-searchers and farmers in identifying potential causes and treatments at early *** study proposes an automatic crop diagnostic system for detecting biotic stresses and managing diseases in four leafy green crops,lettuce,basil,spinach,and parsley,grown in an aquaponics ***,a dataset comprising 2640 images is ***,a disease detection system is developed that works in three *** first phase is a crop clas-sification system that identifies the type of *** second phase is a disease identification system that determines the crop's health *** final phase is a disease detection system that localizes and detects the diseased and healthy spots in leaves and categorizes the *** proposed approach has shown promising results with accuracy in each of the three phases,reaching 95.83%,94.13%,and 82.13%,*** final dis-ease detection system is then integrated with an ontology model through a cloud-based *** ontol-ogy model contains domain knowledge related to crop pathology,particularly causes and treatments of different diseases of the studied leafy green crops,which can be automatically extracted upon disease detection allowing agricultural practitioners to take precautionary *** proposed application finds its significance as a de-cision support system that can automate aquaponics facility health monitoring and assist agricultural practi-tione

关键词： Computer vision Deep learning Disease detection Leafy crops Aquaponics Digital farming

Estimation of morphological traits of foliage and effective plant spacing in NFT-based aquaponics system

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Artificial Intelligence in Agriculture 2023年第3期9卷 76-88页

Deep learning and computer vision techniques have gained significant attention in the agriculture sector due to their non-destructive and contactless *** techniques are also being integrated into modern farming systems,such as aquaponics,to address the challenges hindering its commercialization and large-scale *** is a farming technology that combines a recirculating aquaculture system and soilless hydroponics agriculture,that promises to address food security *** complement the current research efforts,a methodology is proposed to automatically measure the morphological traits of crops such as width,length and area and estimate the effective plant spacing between grow *** spacing is one of the key design parameters that are dependent on crop type and its morphological traits and hence needs to be monitored to ensure high crop yield and quality which can be impacted due to foliage occlusion or overlapping as the crop *** proposed approach uses Mask-rCNN to estimate the size of the crops and a mathematical model to determine plant spacing for a self-adaptive aquaponics *** common little gem romaine lettuce,the growth is estimated within 2 cm of error for both length and *** final model is deployed on a cloud-based application and integrated with an ontology model containing domain knowledge of the aquaponics *** relevant knowledge about crop characteristics and optimal plant spacing is extracted from ontology and compared with results obtained from the final model to suggest further *** proposed application finds its signifi-cance as a decision support system that can pave the way for intelligent system monitoring and control.

关键词： Deep learning Ontology modeling Crop phenotyping Leafy crops Aquaponics Digital farming Plant spacing

Post-annealing effect on the structural and mechanical properties of multiphase zirconia films deposited by a plasma focus device

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Chinese Physics B 2013年第12期22卷 442-450页

作者： I.A.Khan r.S.rawat r.ahmad M.A.K.Shahid Department of Physics Government College University National Institute of Education Nanyang Technological University Department of Physics GC University

Nanostructured multiphase zirconia films （MZFs） are deposited on Zr substrate by the irradiation of energetic oxygen ions emanated from a plasma focus device. The oxygen operating gas pressure of 1 mbar （1 bar=105 Pa） provides the most appropriate ion energy flux to deposit crystalline ZrO2 films. X-ray diffraction （XrD） patterns reveal the formation of polycrystalline ZrO2 films. The crystallite size （CS）, crystal growth, and dislocation densities are attributed to increasing focus shots, sample axial distances, and working gas pressures. Phase and orientation transformations from t-ZrO2 to m-ZrO2 and c-ZrO2 are associated with increasing focus shots and continuous annealing. For lower （200 ℃） annealing temperature （AT）, full width at half maximum （FWHM） of diffraction peak, CS, and dislocation density （δ） for （020） plane are found to be 0.494, 16.6 nm, and 3.63×10-3 nm-2 while for higher （400 ℃） AT, these parameters for （111） plane are found to be 0.388, 20.87 nm, and 2.29×10-3 nm-2, respectively. Scanning electron microscope （SEM） results demonstrate the formation of rounded grains with uniform distribution. The estimated values of atomic ratio （O/Zr） in ZrO2 films deposited for different axial distances （6 cm, 9 cm, and 12 cm） are found to be 2.1, 2.2, and 2.3, respectively. Fourier transform infrared （FTIr） analysis reveals that the bands appearing at 441 cm-1 and 480 cm-1 belong to m-ZrO2 and t-ZrO2 phases, respectively. Maximum microhardness （8.65±0.45 GPa） of ZrO2 film is ～ 6.7 times higher than the microhardness of virgin Zr.

关键词： zrconia phase transformation XrD SEM Fourier transform infrared analysis

reduction in secondary dendrite arm spacing in cast eutectic Al–Si piston alloys by cerium addition

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International Journal of Minerals,Metallurgy and Materials 2017年第1期24卷 91-101页

作者： r.ahmad M.B.A.Asmael N.r.Shahizan S.Gandouz Department of Manufacturing and Industrial Engineering Faculty of Mechanical and Manufacturing EngineeringUniversiti Tun Hussein Onn MalaysiaParit Raja86400 Batu PahatJohorMalaysia

The effects of Ce on the secondary dendrite arm spacing（SDAS） and mechanical behavior of Al-Si-Cu-Mg alloys were investigated. The reduction of SDAS at different Ce concentrations was evaluated in a directional solidification experiment via computer-aided cooling curve thermal analysis（CA-CCTA）. The results showed that 0.1wt%-1.0wt% Ce addition resulted in a rapid solidification time, ？ts, and low solidification temperature, ？T_S, whereas 0.1wt% Ce resulted in a fast solidification time, Δ^（ta-Al）, of the α-Al phase. Furthermore, Ce addition refined the SDAS, which was reduced to approximately 36%. The mechanical properties of the alloys with and without Ce were investigated using tensile and hardness tests. The quality index（Q） and ultimate tensile strength of（UTS） Al-Si-Cu-Mg alloys significantly improved with the addition of 0.1wt% Ce. Moreover, the base alloy hardness was improved with increasing Ce concentration.

关键词： eutectic alloys aluminum silicon alloys cerium microstructure dendrites spacing mechanical properties

Solidification, microstructure, and mechanical properties of the as-cast ZrE1 magnesium alloy with different praseodymium contents

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International Journal of Minerals,Metallurgy and Materials 2017年第11期24卷 1306-1320页

作者： Z.M.Sheggaf r.ahmad M.B.A.Asmael A.M.M.Elaswad Department of Manufacturing and Industrial Engineering Faculty of Mechanical and Manufacturing Engineering Universiti Tun Hussein Onn Malaysia Parit Raja86400 BatuPahat Johor Malaysia Department of Mechanical Engineering Eastern Mediterranean University North Cyprus Gazimagsa TRNC Mersin 10 Turkey

The influence of praseodymium(Pr) content on the solidification characteristics, microstructure, and mechanical properties of ZrE1 magnesium(Mg) cast alloy was investigated. The obtained solidification parameters showed that Pr strongly affected the solidification time, leading to refinement of the microstructure of the alloys. When the freezing time was reduced to approximately 52 s, the grain size decreased by 12%. Mg_(12)Zn(Ce,Pr) was formed as a new phase upon the addition of Pr and was detected via X-ray diffraction analysis. The addition of Pr led to a substantial improvement in mechanical properties, which was attributed to the formation of intermetallic compounds; the ultimate tensile strength and yield strength increased by approximately 10% and 13%, respectively. Pr addition also refined the microstructure, and the hardness was recovered. The results herein demonstrate that the mechanical properties of Mg alloys are strongly influenced by their microstructure characteristics, including the grain size, volume fraction, and distribution of intermetallic phases.

关键词： metal solidification microstructure mechanical properties magnesium alloys intermetallics

Numerical Study of Unsteady MHD Flow and Entropy Generation in a rotating Permeable Channel with Slip and Hall Effects

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Communications in Theoretical Physics 2018年第11期69卷 641-650页

作者： Z.H.Khan O.D.Makinde r.ahmad W.A.Khan State Key Laboratory of Hydraulics and Mountain river Engineering College of Water Resource & HydropowerSichuan University Key Laboratory of Advanced reactor Engineering and Safety Ministry of Education Tsinghua University Faculty of Military Science Stellenbosch University School of Mathematics and Physics University of Queensland Faculty of Engineering Sciences GIK Institute of Engineering Sciences and Technology Department of Mechanical Engineering College of Engineering Prince Mohammad Bin Fahd University

This article investigates an unbiased analysis for the unsteady two-dimensional laminar flow of an incompressible, electrically and thermally conducting fluid across the space separated by two infinite rotating permeable *** influence of entropy generation, Hall and slip effects are considered within the flow analysis. The problem is modeled based on valid physical arguments and the unsteady system of dimensionless PDEs (partial differential equations) are solved with the help of Finite Difference Scheme. In the presence of pertinent parameters, the precise movement of the flow in terms of velocity, temperature, entropy generation rate, and Bejan numbers are presented graphically, which are parabolic in nature. Streamline profiles are also presented, which exemplify the accurate movement of the flow. The current study is one of the infrequent contributions to the existing literature as previous studies have not attempted to solve the system of high order non-linear PDEs for the unsteady flow with entropy generation and Hall effects in a permeable rotating channel. It is expected that the current analysis would provide a platform for solving the system of nonlinear PDEs of the other unexplored models that are associated to the two-dimensional unsteady flow in a rotating channel.

关键词： unsteady flow rotating permeable channel MHD slip hall effects entropy analysis finite difference method

Effect of Power and Nitrogen Content on the Deposition of CrN Films by Using Pulsed DC Magnetron Sputtering Plasma

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Plasma Science and Technology 2013年第7期15卷 666-672页

作者： Umm-i-KALSOOM r.ahmad Nisar ALI I.A.KHAN Sehrish SALEEM Uzma IKHLAQ Nasarullah KHAN Department of Physics Govt. College UniversityLahore 54000 Pakistan Department of Physics Govt. College UniversityFaisalabad 38000 Pakistan

CrN thin films are deposited on stainless steel （AISI-304） substrate using pulsed DC magnetron sputtering in a mixture of nitrogen and argon plasma. Two set of samples are prepared. The first set of sample is treated at different powers （100 W to 200 W） in a mixture of argon （95%） and nitrogen （5%）. The second set of samples is treated at different nitrogen concentrations （5% to 20%） in argon （95% to 80%） for a constant power （150 W）. X-ray diffraction （XrD） analysis exhibits the development of new phases related to different compounds. The crystallinity of CrN varies by varying the applied power and nitrogen content. Crystallite size and residual stresses of the CrN （111） plane show similar variation for the applied power and nitrogen contents. Scanning electron microscopy （SEM） analysis shows the formation of a granular surface morphology that varies with the change of powers and nitrogen content. The thickness of the film is measured using SEM cross sectional images and using atomic force microscopy （AFM） scratch analysis. The maximum film thickness （about 755 nm） is obtained for the film deposited at 5% nitrogen in 95% argon at 150 W power. For these conditions, maximum hardness is also observed.

关键词： sputtering crystallinity morphology thickness roughness

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

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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