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81.
With the objective of reducing the hairiness of Siro spun yarns, two types of air‐jet nozzle differing in the angle of sub‐holes and suitable for an air vortex ring spinning system were designed and fabricated. The performance of the JetSiro spinning system on short staple fiber materials and the effects of the different parameters on the hairiness of JetSiro spun yarns, such as nozzle pressure of compressed air, distance between front roller nip and inlet of nozzle, and nozzle structure, were investigated using the Taguchi method. The physical properties of JetSiro spun yarns with those of conventional Siro spun yarns were compared. The results show that the parameters, air pressure and distance between front roller nip and inlet of nozzle have the strongest and weakest effect on yarn hairiness. In addition, the optimum spinning conditions were determined. The application of the air‐jet nozzle exhibits significant reductions in yarn hairiness of 40%. The results revealed no significant effect of the air‐jet nozzle on the yarn tensile properties and evenness.  相似文献   
82.
Titanium Aluminide based composites with Al2O3 reinforcement can be produced via reaction of Al with TiO2. These composites are considered as low price materials for high temperature applications. In this research, the effect of ball milling on 3TiO2/7Al system was investigated. On the basis of obtained results, ball milling for 0 to 60 h does not lead to reduction of TiO2 by Al. but reduces the temperature of exothermic reaction. The article is published in the original.  相似文献   
83.
This study proposes a versatile criterion for estimating quality of images in electrical impedance tomography. The point spread function (PSF) is calculated throughout the domain based on the scattering of energy as responses to a small anomaly spirally moved from the centre to the boundary. The proposed PSF is a measure of weighted spatial variance (WSV) of the conductivity over the whole domain. For each element, the weighting factor is a normalized multiplication of the area of that element by its square intensity. The WSV collectively incorporates all image attributes, i.e., spatial resolution, artifact, amplitude response, positioning error and shape deformation. The location of artifacts, which significantly influences reconstructed images in reality, is taken into account as well. The results illustrate that the proposed measure is more tolerant than existing criteria in evaluating performance of EIT systems in both theory and practice.  相似文献   
84.
In this paper, we present the performance of multi-antenna selective combining decode-and-forward (SC-DF) relay networks over independent but non-identical Nakagami-m fading channels with imperfect channel estimation. The outage probability, moment generating function (MGF) and symbol error probability (SEP) will be derived in closed-form using the SNR statistical characteristics. To make the analysis trackable, we have derived the MGF and SEP for integer values of fading severity, m. Also, to make the relations more simple, we develop high signal to noise ratio (SNR) analysis for the performance metrics of our system. Subsequently, we propose optimal and adaptive power allocation algorithms along with the equal power allocation method. Finally, for comparison with analytical formulas, we perform some Monte-Carlo simulations.  相似文献   
85.
The effects of spray‐drying air temperature, aspirator rate (drying air mass flow rate), peristaltic pump rate (feed mass flow rate) and spraying air mass flow rate on microencapsulation properties of fish oil including moisture content, particle size, bulk density, encapsulation efficiency and peroxide were investigated. The process was carried out on a mini spray dryer, and skim milk powder was used as the encapsulating wall material. Results indicated that increasing inlet air temperature increased the particle size, encapsulation efficiency and peroxide value but decreased the bulk density and moisture content of product. Increasing aspirator rate resulted in increased particle size and peroxide value but decreased the moisture content and bulk density. Increase in feed mass flow rate increased the moisture content, particle size, bulk density and peroxide value but decreased the encapsulation efficiency of microcapsules. The encapsulation efficiency and bulk density increased with the increasing aspirator rate but moisture content, particle size and peroxide value decreased.  相似文献   
86.
Providing precise estimations of soil deformation modulus is very difficult due to its dependence on many factors. In this study, gene expression programming (GEP) and multi-expression programming (MEP) systems are presented to derive empirical equations for the prediction of the pressuremeter soil deformation modulus. The employed expression programming (EP) systems formulate the soil deformation modulus in terms of the soil physical properties. Selection of the best models is on the basis of developing and controlling several models with different combinations of the affecting parameters. The proposed EP-based models are established upon 114 pressuremeter tests on different soil types conducted in this study. The generalization capabilities of the models are verified using several statistical criteria. Contributions of the variables influencing the soil modulus are evaluated through a sensitivity analysis. The GEP and MEP approaches accurately characterize the soil deformation modulus resulting in a very good prediction performance. The result indicates that moisture content and soil dry unit weight can efficiently represent the initial state and consolidation history of soil for determining its modulus.  相似文献   
87.
While many large touchscreen devices have a split keyboard option to enable two-thumb typing, there are significant differences in the design which affect users’ text entry rate. A mixed-integer programming model is developed to optimize key-to-thumb assignment with the objective of minimizing the expected time to type a character. Computer simulations are conducted to determine the optimal key dimension under different values of the Fitts’ law’s slope coefficient, typing error rate, and alternate-hand advantage phenomenon. The results show that text entry rate and the optimal key-to-thumb assignment depend on key dimensions, user’s speed-accuracy profile, and the level of alternate-hand advantage. The optimal keyboard is proposed. To validate the analytical findings, an empirical study is conducted with eighteen users and six different keyboards in terms of key dimensions and typing zone. Empirical results report between 7% and 18% improvement in the text entry rate over the other split keyboards tested.  相似文献   
88.
Sheath blight disease in rice has caused major crop losses worldwide. Managing the causal agent of disease Rhizoctonia solani Kühn is difficult because of its broad host range and formation of sclerotia which can survive in harsh environmental conditions; therefore developing innovative disease management methods without application of hazardous chemicals has been considered as the main concern to maintain sustainable agriculture. This presented research has revealed the negative impact of silver nanoparticles (SNPs) on R. solani and disease progress both in vitro and in vivo. The adverse effects of the SNPs on R. solani are significantly dependent on the quantity of SNPs, sprayed at different concentrations in vitro. The highest inhibition level against sclerotia formation and mycelia growth are 92 and 85%, respectively, at a SNPs concentration of 50 ppm. In vivo glasshouse experiments also showed that SNPs at the same concentration favourably affects both the fresh and dry weight of rice plants with a remarkable suppressive effect on the lesion development in leaves.Inspec keywords: antibacterial activity, silver, nanoparticles, nanomedicine, plant diseases, cropsOther keywords: in vitro antifungal properties, in vivo antifungal properties, silver nanoparticles, rice sheath blight disease, major crop losses, causal agent, Rhizoctonia solani Kühn, sclerotia, harsh environmental conditions, disease management methods, hazardous chemicals, sustainable agriculture, negative impact, inhibition level, mycelia growth, in vivo glasshouse experiments, rice plants, suppressive effect, lesion development, leaves  相似文献   
89.
Recent advancement in cameras and image processing technology has generated a paradigm shift from traditional 2D and 3D video to multi-view video (MVV) technology, while at the same time improving video quality and compression through standards such as high efficiency video coding (HEVC). In multi-view, cameras are placed in predetermined positions to capture the video from various views. Delivering such views with high quality over the Internet is a challenging prospect, as MVV traffic is several times larger than traditional video, since it consists of multiple video sequences, each captured from a different angle, requiring more bandwidth than single-view video to transmit MVV. In addition, the Internet is known to be prone to packet loss, delay, and bandwidth variation, which adversely affect MVV transmission. Another challenge is that end users’ devices have different capabilities in terms of computing power, display, and access link capacity, requiring MVV to be adapted to each user’s context. In this paper, we propose an HEVC multi-view system using Dynamic Adaptive Streaming over HTTP to overcome the above-mentioned challenges. Our system uses an adaptive mechanism to adjust the video bit rate to the variations of bandwidth in best effort networks. We also propose a novel scalable way for the multi-view video and depth content for 3D video in terms of the number of transmitted views. Our objective measurements show that our method of transmitting MVV content can maximize the perceptual quality of virtual views after the rendering and hence increase the user’s quality of experience.  相似文献   
90.
In this paper, a novel method, based on the areas on the left and the right sides of fuzzy numbers is proposed for ranking fuzzy numbers. The merits of the results given here is to overcome certain shortcomings in the recent literature that mostly does not end in the right ordering of fuzzy numbers. The method also has very easy and simple calculations compared to other methods. Moreover, numerical examples are given to compare the proposed method with other existing ones.  相似文献   
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