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11.
Muhammad Maqsood Tanveer Hussain Yasir Nawab Khubab Shaker Muhammad Umair 《纺织学会志》2013,104(11):1180-1189
The aim of this study was to develop statistical models for the prediction of warp and weft crimp percentage of cotton woven fabrics. The developed models are based on the empirical data obtained from carefully developed 60 fabric samples with different yarn linear densities, fabric densities, and weave designs. The predictability and accuracy of the developed models was assessed by correlation analysis of the predicted and actual crimp values of another set of eight fabric samples which was not used for the development of models. The results show fairly good capability and accuracy of the prediction models. 相似文献
12.
Ho2Si2O7 material exists in four polymorphs, a triclinic low temperature phase (type-B), a monoclinic modification (type-C), high temperature monoclinic (type-D), and high temperature orthorhombic modification (type-E). The structural properties are measured by XRD and the morphology is noted through scanning electron microscopy (SEM). The dc electrical resistivity (ρ) as a function of temperature and dielectric properties of C-type Ho2Si2O7 in the microwave region is measured. The activation energy is calculated from ln ρ versus 1/kBT plot. The activation energy is 0.119 ± 0.001 eV. Both the real (?′) and imaginary parts of permittivity (?″) decrease slightly as the frequency increases up to 1.5 GHz, after that ?′ increases while ?″ decreases as the frequency increases. At around 2.45 GHz, resonance is observed. 相似文献
13.
Zezhong C. Chen Maqsood A. Khan 《The International Journal of Advanced Manufacturing Technology》2014,70(5-8):1355-1368
With the development of a new function of computer numerical control controllers, nonuniform rational B-spline (NURBS) interpolation, NURBS tool path generation for sculptured surface machining is under extensive research. The common procedures of the current NURBS tool path planning methods are as follows: first, to find a group of cutter contact points on a sculptured surface; second, to calculate their corresponding cutter locations (CLs); then, to fit a NURBS tool path to the CLs within a prescribed tolerance; and finally, to inspect the tool path for possible gouge by the tool and delete the invalid path segments, if any. However, the NURBS tool path has the following problems: (a) although it passes through the discrete CLs of the theoretical CL path, the deviation along the two paths could be larger than the tolerance; (b) its parameter is not the arc length of the path; and (c) it is difficult to detect gouge along the NURBS path and to remove the invalid segments from it. Consequently, NURBS tool paths generated with the current methods of commercial computer-aided design/computer-aided manufacturing (CAD/CAM) software cannot be used to make smooth and accurate surfaces. To address these problems, this work proposes a new approach to generating arc length parameterized NURBS tool paths with high accuracy in terms of the theoretical CL paths and without gouge and interference. Two practical examples in this work clearly demonstrate the feasibility of this approach and the advantages of the generated NURBS tool paths. Therefore, this approach can be implemented into the CAD/CAM software to promote NURBS machining in industry. 相似文献
14.
Bulk superconductors of the (Bi1–x
Pb
x
)2Sr2Ca2Cu3O
y
system have been synthesized by changing the Bi/Pb ratio. The effect of Pb substitution onT
c has been studied by standard d.c. resistivity measurements. An appropriate thermal procedure and time for the preparation of the 110 K phase has also been studied at length. The experiments indicate that the best results are obtained forx=0.2 and that a slow cooling process is necessary for a better control of the thermal process. Indexed X-ray diffraction patterns indicate the lattice parameters of low- and high-T
c phases asa
L=0.54004 nm,b
L=0.5445 nm,c
L=3.084 nm anda
H=0.5483 nm,b
H=0.5339 nm,c
H=3.772 nm, respectively. The observed superconducting behaviour is stable on thermal cycling between 77 and 300 K. 相似文献
15.
An interval-parameter two-stage stochastic mixed integer programming (ITMILP) technique is developed for waste management under uncertainty. It is a hybrid of inexact two-stage stochastic programming and mixed integer linear programming methods. The ITMILP method can directly handle uncertainties expressed not only as probability density functions but also as discrete intervals. It can be used to analyse various policy scenarios that are associated with different levels of economic penalties when the promised policy targets are violated. More importantly, it can facilitate dynamic analysis of decisions on capacity expansion planning within a multi-region, multi-facility, multi-period, and multi-option context. The results will help to generate a range of decision alternatives under various system conditions, and thus offer insight into the trade-offs between environmental and economic objectives. The ITMILP method is applied to planning facility expansion and waste flow allocation within a waste management system. The results indicate that reasonable solutions have been generated for both binary and continuous variables. The binary-variable solutions represent the decisions of facility expansion, while the continuous-variable solutions are related to decisions on waste flow allocation. 相似文献
16.
The effect of the addition of barium on the zero resistance temperature,T
c, of Bi1.6Pb0.4Sr1.6Ca2Ba
x
Cu4O
y
,x= 0.4, 0.5, 0.6, 0.8 and 1.6 was studied. The added barium had the effect of raisingT
c to a higher temperature region, although too much barium gave rise to semiconducting resistance temperature behaviour. X-ray diffraction analysis showed that as the barium concentration,x, increased from 0.4 to 0.8, a decrease in the lowT
c phase and peaks due to CuO and BaBiO3 appeared, whereas an increase in the peaks due to the highT
c phase and BaCuO2 were seen. Critical current densities were also measured in zero field at 77 K. 相似文献
17.
Simultaneous measurements of thermal conductivity and thermal diffusivity of composite red-sand bricks, glycerine and mercury have been made at room temperature by the recently developed transient plane source (TPS) technique. This paper describes, in brief, the theory and the experimental conditions for the simultaneous measurements of thermal conductivity and thermal diffusivity of insulators, fluids and metals. The source of heat is a hot disc made out of bifilar spirals. The disc also serves as a sensor of temperature increase in the sample. The measured values of the thermal conductivity and thermal diffusivity of these samples are in agreement with the values reported earlier using other methods. The advantage of the TPS technique is the simplicity of the equipment, simultaneous information on thermal conductivity and thermal diffusivity, and also the applicability of the technique to insulators, fluids and metals. 相似文献
18.
B. M. Wanklyn F. R. Wondre A. Maqsood K. Yanagisawa W. Davison 《Journal of Materials Science》1979,14(6):1447-1456
The flux growth of crystals of the following complex fluorides is reported: KAlF4, KMnF3, RbFeF4, Rb2FeF5, Rb3FeF6, Rb
x
FeF3 (0.18<x<0.29), CsFeF4, CsFe2F7, Cs3Fe2F9, Cs
x
FeF3 (0.18<x<0.29), Na2CoFeF7, Na2NiFeF7, Na2NiAlF7, Na2ZnCrF7, NaCrF4 and Rb2Cr5F17. Flux impurity levels, determined by electron probe microanalysis (EPMA), were low. However, attempts to produce BaNiF4, BaCoF4, CsCrF4 and Cs2Cr5F17 resulted in crystals with higher levels of substitutional impurities. X-ray powder patterns and EPMA were used to characterize the crystals. 相似文献
19.
M. Arif Khan Nazar A. Shah A. Ali M. Basharat M. A. Hannan A. Maqsood 《Journal of Coatings Technology and Research》2009,6(2):251-256
Cd-enriched cadmium telluride (CdTe) polycrystalline films were grown on corning glass substrates by close spaced sublimation
(CSS) technique. To our knowledge, Cd-enriched CdTe thin films by CSS have not been reported earlier. The structural investigations
performed by means of X-ray diffraction (XRD) technique, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy
(EDX) showed that the deposited films exhibit a polycrystalline structure with 〈111〉 as preferred orientation. The structural,
optical, and electrical properties of these films were analyzed as a function of the Cd concentration. For the films having
an excess of Cd, the electrical resistivity dropped several orders of magnitude. The deposited films also showed that the
value of resistivity decreased with increasing temperature manifesting the semiconducting behavior of the films. The results
showed that using this deposition technique, n-type Cd-enriched CdTe polycrystalline film could be produced. 相似文献
20.
Sitara Afzal Muazzam Maqsood Irfan Mehmood Muhammad Tabish Niaz Sanghyun Seo 《计算机、材料和连续体(英文)》2021,66(3):2301-2315
Cerebral Microbleeds (CMBs) are microhemorrhages caused by certain abnormalities of brain vessels. CMBs can be found in people with Traumatic Brain Injury (TBI), Alzheimer’s disease, and in old individuals having a brain injury. Current research reveals that CMBs can be highly dangerous for individuals having dementia and stroke. The CMBs seriously impact individuals’ life which makes it crucial to recognize the CMBs in its initial phase to stop deterioration and to assist individuals to have a normal life. The existing work report good results but often ignores false-positive’s perspective for this research area. In this paper, an efficient approach is presented to detect CMBs from the Susceptibility Weighted Images (SWI). The proposed framework consists of four main phases (i) making clusters of brain Magnetic Resonance Imaging (MRI) using k-mean classifier (ii) reduce false positives for better classification results (iii) discriminative feature extraction specific to CMBs (iv) classification using a five layers convolutional neural network (CNN). The proposed method is evaluated on a public dataset available for 20 subjects. The proposed system shows an accuracy of 98.9% and a 1.1% false-positive rate value. The results show the superiority of the proposed work as compared to existing states of the art methods. 相似文献