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4D Printing: Future Insight in Additive Manufacturing
Muhammad Qasim Zafar,Haiyan Zhao 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.5
Development in additive manufacturing is exceptionally rapid than the expected forecast so far and it has traced out newdimensions in engineering applications. 3D printing technology becomes more glamorous when Skylar Tibbits incorporatedthe concept of “Time” as a fourth dimension by encapsulating smart materials in current additive manufacturing technique. Materials having an explicit response to external stimuli over a certain time span are designated as smart materials and additivemanufacturing of such time-dependent, programmable, and intelligent materials is termed as 4D printing. In 4D printing,primary 3D printed configuration switched exclusively into a transformed shape when exposed to an external stimuli,e.g. heat, light, water, chemical, electric current, magnetic field or pH. Perhaps, additive manufacturing technology seemsto be superseded exclusively by this modern technology in forthcoming years, and much effort is demanding from everydiscipline to actualize this technology. A task-oriented entire landscape of 4D printing followed by a comprehensive smartmaterial perspective is presented in this review. Graphical abstract set forth a route to the complete process comprehension. Moreover, other components of 4D technology like customary techniques, computational challenges, reversibility and currentstature of 4D printing are probed through recent experimental and theoretical literature. Finally, potential applicationsof 4D printing are summarised with promising research directions and outlook.
Natural convection effects on heat and mass transfer of slip flow of time-dependent Prandtl fluid
Muhammad Hamid,Tamour Zubair,Muhammad Usman,Zafar Hayat Khan,Wei Wang 한국CDE학회 2019 Journal of computational design and engineering Vol.6 No.4
We proposed a mathematical model for an incompressible, viscous, natural convection, and stagnation point slip flow of MHD Prandtl fluid over an infinite plate. The governing flow equations are constructed using the Prandtl rheological model. In account of physical relevance, we investigated the Soret and Dufour effects on the flow field. The complex natured flow equations are transformed to a set of PDEs using a suitable similarity variables. The non-dimensionalized ruling problem together with physical boundary conditions is numerically analyzed via Crank-Nicolson scheme. The velocity, temperature and concentration of the diffusing species distributions are enhanced for higher values of unsteadiness parameter. It is noted that velocity is slightly decreasing for higher values of Reynolds number while smaller values of Re providing more dominant effects on the velocity, temperature and concentration of the diffusing species profiles and enhanced heat and mass transfer rates is noticed. The physical behav-ior of reduced Nusselt and Sherwood numbers, friction factor, for distinct values of emerging parameters is examined and representative set of graphs are presented.
A Clustering Based Study of Classification Algorithms
Muhammad Husnain Zafar,Muhammad Ilyas 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.1
A grouping of data objects such that the objects within a group are similar (or related) to one another and different from (or unrelated to) the objects in other groups. Many of clustering algorithm is available to analyze data. This paper intends to study and compare different clustering algorithms. These algorithms include K-Means, Farthest First, DBSCAN, CURE, Chameleon algorithm. All these algorithms are compared on the basis of their pros and cons, similarity measure, their working, functionality and time complexity.
Oral Tissue Engineering Progress and Challenges
Muhammad Sohail Zafar,Zohaib Khurshid,Khalid Almas 한국조직공학과 재생의학회 2015 조직공학과 재생의학 Vol.12 No.6
Tissue engineering is a multidisciplinary science. The progress of tissue engineering for dental tissues is promising and various dental soft and hard tissues have been regenerated successfully in vitro using stem cells. Prior to their applications practically, there are a number of challenges and unanswered questions that need to be resolved for further progress. It is expected that in next two to three decades, the field of dentistry will be changed significantly by the availability of innovative tissue engineered products in dental office. The objective of this review paper is to highlight the progress of tissue engineering for various dental hard and soft tissues such as enamel, dentin, alveolar bone, periodontium, oral mucosa, and salivary glands. In addition, the challenges in the progress of tissue engineering and future expectations have been discussed.
Muhammad Kamran,Nazir Javed,Ihsan Ullah,Shahid Nazir,Shakra Jamil,Muhammad Zafar Iqbal,Huma Abbas,Sajid Aleem Khan,Muhammad Ehetisham ul Haq 한국식물병리학회 2019 Plant Pathology Journal Vol.35 No.1
A great variable response was observed when PP-3 and PP-J encumbered with 116 populations of root knot nematode (RKN) at two different temperatures (25 ± 2°C and 30 ± 2°C) and concentrations (104 and 105 spores/ml). The PCR reaction amplified intergenic region between cytochrome oxidase subunit II gene (COII) and large subunit of rRNA gene (lrRNA) of the mitochondrial genome of different RKN species. The primer C2F3 and 1108 identified M. incognita with the highest frequency (52.6%) followed by M. javanica (36.8%) and M. arenaria (10.5%). The sizes of PCR products were 1.7 kb for M. incognita and M. javanica populations while populations of M. arenaria produced 1.1 kb fragment. The digestion with Hinf I yielded three different fragment length patterns on 1.5 % agarose gel. From current research it is concluded that intra-Meloidogyne genetic variability exist in RKN populations which have better encumbrance with P. penetrans.
Muhammad Zafar,윤주영,김도형 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.2
Atomic layer deposition (ALD) was used to synthesize titanium oxide (TiO2) film as an electron transport layer (ETL) in inverted organic photovoltaic cells (IOPVs). By adjusting the ALD precursor ratio and deposition temperature, the thickness of the TiO2 film was 5 nm, and its effect on the photovoltaic performances was evaluated. We also investigated the effect of nitrogen doping of TiO2 on the power conversion efficiency (PCE) of the cells. An IOPV cell fabricated with a 0.6%-nitrogen-doped TiO2 (N-TiO2 A) ETL exhibited a PCE of 2.27%, which is a 6% increase compared with an equivalent cell containing an undoped TiO2 ETL. Furthermore, the XPS results confirmed the doping of nitrogen into the samples. The doping improved the electrical properties of the TiO2 films evidenced by the Hall measurements in terms of conductivity, hall electron mobility and carrier density.