Polypropylene/Spray Dried and Silane-Treated Nanofibrillated Cellulose Composites

In this study, the spray dried nanofibrillated cellulose (NFC) was modified by a silane coupling agent to be used in polypropylene (PP)-copolymer matrix in the presence of maleic anhydride grafted PP (PP-g-MAH) compatibilizer. The PP/NFC composites were melt compounded and injection molded. In the first stage, the NFC was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). It was shown that fibrillation in aqueous media through high-pressure homogenization was successfully achieved. The nanofibrils having diameter smaller than 50 nm were obtained. The X-ray photo electron spectroscopy (XPS) showed the presence of the silane groups on the NFC surface. Elastic modulus improved by the addition of the high modulus NFC to PP, but the yield strength was not improved. On the other hand, different than many inorganic micron-sized fillers, the elongation-at-break value did not drop much. Differential scanning calorimeter experiments indicated that the NFC acted as a nucleating agent. Rheological investigations exhibited that NFC decreased the viscosity of the PP. The addition of NFC to PP improved the thermal resistance of the PP as can be understood from the TGA experiments. It was demonstrated that renewable nanofiller can be a feasible method to functionalize the existing synthetic polymers. POLYM. ENG. SCI., 60: 352–361, 2019. © 2019 Society of Plastics Engineers     

An improved adaptive FastSLAM algorithm with time-varying noise estimator

In this study, an adaptive FastSLAM (AFastSLAM) algorithm, which is obtained by estimating the time-varying noise statistics and improving FastSLAM algorithm, is proposed. This improvement was accomplished by using maximum likelihood estimation and expectation maximization criterion and a one-step smoothing algorithm in importance sampling. In addition, innovation covariance estimation (ICE) method was used to prevent loss of positive definiteness of the process and measurement noise covariance matrices. The proposed method was compared with FastSLAM by calculating the root mean square error (RMSE) using different particle numbers at varying initial process and measurement noise values. Simulation studies have shown that AFastSLAM provides much more accurate, consistent, and successful estimates than FastSLAM for both robot and landmark positions.     

Accessibility,usability, and security evaluation of universities’ prospective student web pages: a comparative study of Europe,North America,and Oceania

Universal Access in the Information Society - Universities' prospective student web pages aim to disseminate information about their academic and social opportunities to their stakeholders;...     

PHEMA cryogel for in-vitro removal of anti-dsDNA antibodies from SLE plasma

Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA) cryogel carrying DNA was used in the removal of anti-dsDNA antibodies from systemic lupus erythematosus (SLE) patient plasma. The PHEMA cryogel was prepared by bulk polymerization which proceeds in an aqueous solution of monomer frozen inside a plastic syringe. After thawing, the PHEMA cryogel contains a continuous matrix having interconnected macropores of 10–200 μm size. Pore volume in the PHEMA cryogel was 67.5%. Ester groups in the PHEMA structure were converted to imine groups by reacting with poly(ethyleneimine) (PEI) in the presence of NaHCO₃. Amino (? NH₂) content of PEI-modified PHEMA cryogel was determined as 82 mg PEI/g. Then, DNA was attached onto the PHEMA cryogel via amino groups (53.4 mg DNA/g cryogel). Anti-dsDNA-antibody concentration declined significantly from 780 IU/ml to 80 IU/ml with the time. The maximum anti-dsDNA-antibody adsorption amount was 70 × 10³ IU/g. Anti-dsDNA-antibodies could be repeatedly adsorbed and eluted without noticeable loss in the anti-dsDNA-antibody adsorption amount.     

On His Majesty's Service: Bangkok's architects between autonomy and heteronomy

This paper takes the example of ‘Siam’, the modern city centre of Bangkok, to analyse how architects cope with traditional power structures, torn as they are between the autonomy ascribed to their profession by architectural discourse and the practical heteronomy of their work. Most of the land around ‘Siam’ is owned by Thailand's Royal Family and the monarchy's investment arm. Hence, local and international architects had to develop the prestigious shopping arcades and hotels that cluster along ‘Siam's’ main road Rama I in the interest of a powerful client: the monarchy and its conservative guardians. Kingship has retained a hegemonic position in Thai politics and society, and is protected against criticism by harsh anti-defamation laws. Architects have to deal with this traditional-authoritarian power apparatus, thereby risking abandoning their creative freedom completely. Based on interviews with professionals from France, Thailand and Singapore the paper analyses how the external forces architects encounter in Bangkok impact on their work. Especially in the context of non-European societies the question arises anew whether the autonomy ascribed to architects is nothing more than a mere chimera.     

Proposing an agricultural belt to protect a city’s semi-rural characteristics: The example of Bartın,Turkey

Urban sprawl, a type of urban expansion, is perceived as a global problem due to changes in land conversions and landscape patterns. Farms, forests and shores have been converted into urban areas; this transformation affects energy flow, biochemical cycles and climatic conditions. To follow and evaluate the physical, social and ecological results of urban sprawl, we identified and measured temporal changes in land use and land cover. This is especially important for urban planning policies. In this study, temporal change is identified in the city of Bart?n using remote sensing and landscape metrics. An analysis of land cover and land transformation was done with LANDSAT5 TM/ETM satellite images from 1985 and 2015. These images were used to identify agricultural areas as land that has most commonly undergone drastic changes. Bart?n is a small semi-rural city that has undergone significant changes. Among the most important reasons for these changes were uncontrolled urban sprawl due to political and administrative decisions that lacked long-term planning and a comprehensive city plan. This study examined the risk factors for loss of semi-rural characteristics using the example of Bart?n city. To protect semi-rural city characteristics and control urban sprawl, we propose an agricultural belt based on spatial suitability and an evaluation of landscape metrics.     

Chemical and sensory quality changes of fish fingers,made from mirror carp (Cyprinus carpio L., 1758), during frozen storage (−18 °C)

The effects of frozen storage at −18 °C on the chemical and sensory qualities of fish fingers produced from unwashed and washed mirror carp (Cyprinus carpio) mince were investigated. The amounts of moisture, crude protein, lipid, crude ash, ω3 polyunsaturated fatty acids (PUFA ω3), and ω6 polyunsaturated fatty acids (PUFA ω6) in fish fingers produced from unwashed mince (UWF) were found to be 68.50%, 15.5%, 6.00%, 2.20% 2.31%, and 55.2%, respectively, while they were found to be 70.23%, 10.8%, 2.14%, 1.80%, 2.28%, and 54.6%, respectively, in carp fingers produced from washed mince (WF). The thiobarbituric acid value (TBA, mg malonaldehyde/kg) was found to be significantly higher in mince of WF than in mince of UWF and increased significantly during frozen storage in both the mince of UWF and WF (p < 0.05). A significant decrease in pH was obtained throughout the washing treatment (p < 0.05). There were no significant differences of pH in either the mince of UWF or WF between the beginning and end of the storage periods (p > 0.05), whereas a sharp increase was observed in the fourth month in both groups. The protein solubilities of the mince of both UWF and WF decreased significantly throughout the storage periods (p < 0.05). Sensory parameters of colour, odour, flavour, and general acceptability for both groups decreased during the frozen storage period (p < 0.05) but were still within acceptable limits. It was also concluded that mirror carp was a good source for fish fingers and that product could be stored for five months in a frozen state without undesirable changes of sensory and chemical qualities.     

Polynomial Response Surface Approximations for the Multidisciplinary Design Optimization of a High Speed Civil Transport

Surrogate functions have become an important tool in multidisciplinary design optimization to deal with noisy functions, high computational cost, and the practical difficulty of integrating legacy disciplinary computer codes. A combination of mathematical, statistical, and engineering techniques, well known in other contexts, have made polynomial surrogate functions viable for MDO. Despite the obvious limitations imposed by sparse high fidelity data in high dimensions and the locality of low order polynomial approximations, the success of the panoply of techniques based on polynomial response surface approximations for MDO shows that the implementation details are more important than the underlying approximation method (polynomial, spline, DACE, kernel regression, etc.). This paper selectively surveys some of the ancillary techniques—statistics, global search, parallel computing, variable complexity modeling—that augment the construction and use of polynomial surrogates.     

Performance of FRP-Strengthened RC Beams with Different Concrete Surface Profiles

Performance of fiber-reinforced polymer (FRP) composites in repair and retrofit of concrete structures depends to a great extent on the substrate condition to which it is bonded. The present research investigated the effect of concrete surface roughness on the bond behavior and general performance of FRP strengthening systems. The study included flexural testing of 26 specimens with two different carbon FRP systems (wet layup and precured) and three different levels of surface roughness. The influence of six different levels of anchorage by means of U-straps was also evaluated. Additionally, 10 bond specimens were tested in double shear for the wet layup FRP system to compare with the results of beam tests and to further investigate the debonding issue. Bond-dependent coefficient was analyzed with respect to different levels of surface roughness and shear span-to-depth ratio, and was then compared with other test results available in the literature. Surface roughness did not appear to have a significant influence on the overall performance of the FRP strengthening system with or without adequate anchorage, and whether failure was by debonding or rupture of FRP.