Optimal deflection and stacking sequence prediction of curved composite structure using hybrid (FEM and soft computing) technique

Engineering with Computers - The bending deflections and the corresponding optimal fiber angle sequences of the subsequent layers have been predicted in this article using a hybrid technique. The...     

Investigation of the elastic properties of poly (methyl methacrylate) reinforced with graphene nanoplatelets

The technique for synthesis of poly (methyl methacrylate) (PMMA) by atom transfer radical polymerization has been strengthened by using graphene nanoplatelets (GNPs) to enhance the elastic properties of the polymer. In order to improve practical, economical and mechanical performance, the requirements for effective implementation of production control as a smart bulk polymer nanocomposite were determined for cost-effective bulk production. Three-dimensional inspection (using an ultrasound interrogation method for the whole volume under test) confirmed the synthesis of the nanocomposite to be free of agglomeration and bubbles. As a result of this elimination of defects, an enhancement in compressive strength of 42.7% was achieved and the Rockwell hardness was increased by 19.9% through the addition of GNPs at 2 wt% by mass. The deformation and mechanical failure properties have been characterized in the mechanical enhancement of the polymer nanocomposite. Elastic parameters determined using ultrasound testing identified that changes in the structural features following the addition of these GNPs were uniquely connected to the enhancements in these elastic parameters (such as Young's modulus, Poisson's ratio, shear modulus, and microhardness) of the PMMA/GNPs nanocomposite.     

Thermodynamic analysis of a Proton Exchange Membrane fuel cell

In this study, energy and exergy analyses of a 1 kW Horizon H-1000 XP Proton Exchange Membrane (PEM) Fuel Cell has been investigated. A testing apparatus has been established to analyze the system efficiencies based on the first and second laws of thermodynamics. In this mechanism pure hydrogen has been directly used as a fuel in compressed gas formation. Purity of hydrogen was above 99.99%. The system performance was investigated through experimental studies on energy and parametric studies on exergy by changing the operating pressure and operation temperature. The results showed that the energy efficiency of PEM fuel cell is 45.58% for experimental study and 41.27% for parametric study at full load. Also, 2.25% and 4.2% performance improvements were obtained by changing the operating temperature ratio (T/T₀) from 1 to 1.2 and operating pressure ratio (P/P₀) from 1 to 2, respectively.     

Improving the dyeability of poly (lactic acid) fiber using octa (aminophenyl) POSS nanoparticle during melt spinning

Disperse dye structure affects the dyeability of poly (lactic acid) (PLA) fiber due to the low dyeing temperature and the short dyeing time. Thus, the dye uptake value of PLA fiber is low for some disperse dyes and needs to be improved. In this study, the dyeability of PLA fiber is improved with the addition of synthesized octa (aminophenyl) polyhedral oligomeric silsesquioxane (OAP-POSS) nanoparticle during the melt spinning process. The effects of dyeing conditions including dyeing temperature and time, OAP-POSS concentration, disperse dye types, and concentrations are investigated on the dyeability properties of PLA fiber samples. The tensile, thermal, and morphological properties of the fiber samples are also characterized by tensile testing, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. It is concluded that the percent crystallinity and the tensile strength of pure PLA fiber decrease as the added amount of OAP-POSS increases. According to the dyeing results, OAP-POSS, which behaves as a good sorbent for the disperse dyes used in this study, greatly improves the dyeability of PLA fiber, especially for disperse dyes with low dye uptake values.     

A New Application Based on GPLVM,LMNN, and NCA for Early Detection of the Stomach Cancer

In this article, speeded-up robust features (SURF) for each image have been calculated. Discrete Fourier transform (DFT) method has been applied to these SURF. High dimensions of these SURF–DFT feature vectors are reduced to low dimensions with large-margin nearest neighbor (LMNN), Gaussian process latent variable models (GPLVM), and neighborhood component analysis (NCA). When size reduction process was done, effect on the GPLVM, LMNN, and NCA of the 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 feature numbers has been examined. These features are classified by naive Bayes (NB) classifier. Thus, SURF_DFT_GPLVM_NB, SURF_DFT_NCA_NB, and SURF_DFT_LMNN_NB methods for gastric histopathological images have been developed. Classification results obtained with these methods have been compared. According to the obtained results, the highest classification result was obtained as 90.24% by using 4 features by SURF_DFT_GPLVM_NB method for second group images.     

Virtual business operations, e-commerce & its significance and the case of Turkey: current situation and its potential

21^st century is the age of high technologies penetrated into business leading to virtual businesses and e-commerce applications combined with electronic business (e-business) structures. Virtual businesses are independent and/or partly dependent organizations that have flexible and agile structures to respond the altering business conditions. Yet, electronic commerce (e-commerce) is the exchange of goods and services over the Internet. Both virtual businesses and e-commerce operations enable organizations to have fluid structures, modify the changing conditions, lower expenses, access to new markets and attain new consumers. The e-commerce applications have also been increasing in Turkey at a great pace but not significantly when compared to the total trade volume. For, the aim of this paper is to focus on the virtual businesses, e-commerce, harmonization of the conventional business structures with e-commerce and emphasize the importance of the e-commerce applications in Turkey resting on dependable national and international publications and data. With respect to the research made, it is possible to state that the e-commerce volume of Turkey is increasing as a remedy to cover the foreign trade deficit, but it is still not sufficient when compared to the total trade volume. Additionally, even though Turkey possesses an efficient e-government mechanism and e-signature law to enhance the volume of its e-commerce, the lack of cooperation among parties and standardization as well as the difficulty in adoption of digital transactions would be issues to be tackled in order to develop e-commerce in Turkey.