The effect of innovation on productivity: evidence from Turkish manufacturing firms

This paper systematically explores the effects of firms’ innovation activities on their productivity changes for Turkish manufacturing firms, differentiating between different typologies of innovation. We employ endogenous switching methodology, controlling for endogeneity and selection bias issues, as well as analysing counterfactual scenarios. The main finding of the study points to firm heterogeneity in terms of propensity both to innovate and to benefit from innovation activities. Our results indicate that all types of innovation activity have positive effects on the productivity of firms when compared with non-innovating firms. We find robust evidence for the differential impact of innovation on firm productivity across different innovation types. Further, this relationship alters across different phases of the economy with respect to the 2008 financial crisis.     

Editorial: Securing Internet of Things Through Big Data Analytics

Mobile Networks and Applications -     

Use of Viburnum Opulus L.(Caprifoliaceae) in Dyeing and Antibacterial Finishing of Cotton

ABSTRACT

It is known that use of chemicals can cause different problems to human health and environment. Therefore, studies to find alternative chemical free finishing processes in textile are now interesting topics. In the light of this, it was tried to minimize chemical uses for antibacterial finishing of cotton by using plant sources “cranberry fruit” and “cranberry fruit branch extract” in dyeing processes. The dyeing experiments were carried out at two different temperatures for different durations. Then, the samples were analyzed in terms of K/S, CIE L*a*b*C* and h° values, light fastness, washing fastness, and antibacterial efficiencies. Consequently, it was found that the two natural dye sources could color the cotton-knitted fabrics, and in general, the washing fastness of dyed samples with both natural dye sources was good, but light fastness values were limited and in dyeing processes by using cranberry fruit branch extract it was poor. Moreover, it was seen that among the tested plantal sources, good antibacterial efficiency against the tested bacteria were obtained with the use of cranberry fruit juice in dyeing processes at low temperature and for lower durations.     

Optimization of synthesis conditions of a novel carrageenan‐based superabsorbent hydrogel by Taguchi method and investigation of its metal ions adsorption

The Taguchi method, a robust experimental design, was used for optimization of synthesis of a novel biopolymer‐based superabsorbent hydrogel, kappa‐carrageenan (κ‐C)‐g‐acrylic acid (AA)‐co‐2‐acrylamido‐2‐methylpropanesulfonic acid (AMPS). The Taguchi method was applied for the experimental and standard 18 orthogonal arrays (OA) with seven factors and three levels for each factor. In the synthesis of the superabsorbent, N,N'‐methylene bisacrylamide (MBA) as crosslinker, ammonium persulfate (APS) as initiator, monomer ratio (AA/AMPS), κ‐C concentration, Total Monomer, neutralization percent (NU), and reaction temperature were used as important factors. After analyzing with analysis of variance (ANOVA) results showed that maximum water absorption capability for optimized final product was found to be 1195 g water per one gram of dry hydrogel powder. The proposed mechanism for the grafting and chemically crosslinking reactions was proved with FTIR, SEM, and TGA methods. Furthermore, the absorption capability of the hydrogels towards bivalent metal ions was evaluated. Therefore, the hydrogels may be based‐considered as a candidate to develop an efficient biofilm absorbent in water treatment applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Optimization of synthetic conditions of a novel collagen‐based superabsorbent hydrogel by Taguchi method and investigation of its metal ions adsorption

A novel biopolymer‐based superabsorbent hydrogel was synthesized through chemical crosslinking by graft copolymerization of partially neutralized acrylic acid onto the hydrolyzed collagen, in the presence of a crosslinking agent and a free radical initiator. The Taguchi method, a robust experimental design, was employed for the optimization of the synthesis reaction based on the swelling capacity of the hydrogels. This method was applied for the experiments and standard L₁₆ orthogonal array with three factors and four levels were chosen. The critical parameters that have been selected for this study are crosslinker (N,N′‐methylene bisacrylamide), initiator (potassium persulfate), and monomer (acrylic acid) concentration. From the analysis of variance of the test results, the most effective factor to control equilibrium swelling capacity was obtained and maximum water absorbency of the optimized final product was found to be 500 g/g. The surface morphology of the gel was examined using scanning electron microscopy. Furthermore, the sorption capacity of the hydrogel toward bivalent metal ions was evaluated. Therefore, the hydrogel may be considered as a candidate to develop as an efficient biopolymer‐based chelating hydrogel for water treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4878–4885, 2006     

Solution of nonlinear boundary layer equation for flat plate via optimal homotopy asymptotic method

In this article, we use the optimal homotopy asymptotic method (OHAM) to compute the solution of two‐dimensional incompressible laminar boundary layer flow over a flat plate (Blasius problem). The obtained results for the stream function and velocity profile were comparable in terms of accuracy with that obtained by Esmaeilpour and Ganji (2007) who studied the same problem using the homotopy perturbation method and results obtained by using a numerical method (RK4). The good agreement obtained shows the effectiveness of OHAM. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(3): 197–203, 2014; Published online 19 June 2013 in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21070     

Optimized synthesis of carrageenan‐ graft‐poly(sodium acrylate) superabsorbent hydrogel using the Taguchi method and investigation of its metal ion absorption

The Taguchi method, a robust experimental design, was used for the optimization of the synthesis of a novel biopolymer‐based superabsorbent hydrogel, carrageenan‐graft‐poly(sodium acrylate). The Taguchi method was applied for the experiment and standard 16 orthogonal arrays with five factors and four levels for each factor were used. In the synthesis of the superabsorbent hydrogel, N,N′‐methylene bisacrylamide (MBA) was used as crosslinker, ammonium persulfate as initiator, and acrylic acid as monomer. Neutralization percent and reaction temperature were used as important factors. The analysis of variance results showed that the most important factor in this synthesis was MBA concentration. Under the optimized conditions determined, the maximum capacity of swelling in distilled water was found to be 1383 (g (g dried gel)^?1). Furthermore, the absorption capacity of the hydrogel towards bivalent metal ions was evaluated. The hydrogel may be considered as a candidate to develop an efficient absorbent biopolymer in water treatment applications. Copyright © 2006 Society of Chemical Industry     

Recent observations in bridge deck aeroelasticity

The Deer Isle Bridge, opened for traffic about the same time as the old Tacoma Narrows Bridge, has a deck section shape which resembles that of the ill fated bridge. Because of the Tacoma Narrows experience, various structural stiffening systems were added to the Deer Isle Bridge to alleviate the type of wind response that destroyed its contemporary. In addition, the Deer Isle Bridge deck is also provided with open-grate vents to improve its aerodynamics. The Deer Isle Bridge remained active under wind even with these modifications, though an earlier study has confirmed the efficacy of the structural modifications in stiffening the bridge. It has been the subject of an extensive field survey by the Federal Highway Administration for the last several years. The present paper summarizes the results of a wind tunnel investigation of a two-dimensional scale model of the Deer Isle Bridge deck, new techniques used in the experiments and the conclusions drawn therefrom on the aeroelasticity of these bluff sections. This forms a part of a comprehensive study centered on the field experiments on the Deer Isle Bridge.     

Natural functionalisation of a traditional textile “Ehram”

This study is focused on the natural functionalisation of a traditional woven fabric called “Ehram”. Which is a wool based woven fabric constituted from wool yarns that are originally coloured and used in different cities of the Eastern Anatolian Region, Turkey. Because these fabrics were originally coloured (pigmented), the study aimed to functionalise them with minimal colour changes from their original colour. For this aim; lavender (Lavandula angustifolia) which is also a natural source of pleasant odour was used in finishing of Ehram. The colour changes by the application of the lavender on Ehram and the benefits that come out from the use of lavender were then analysed and presented in the study. In this respect, antibacterial activities (against Staphylococcus aureus and Escherichia coli) of dyed samples were tested within the scope of the study. In addition, colour measurements (K/S and CIE L*a*b* C* and h^o) and FTIR (Fourier-transform infrared) microspectroscopy analyses of dyed fabric samples were made and microscope images were taken. It was observed that lavender with a copper-based mordanting agent can present antibacterial activity against S. aureus and E. coli in Ehram.     

Topping of naturally dyed wool fabrics with different natural dye sources

Wool fabrics can be dyed with synthetic dyes and even with natural dyes. To present a different aspect to the coloration of wool, the current study was focused on a topping process (ie, the dyeing of wool that was already dyed) with different natural dye sources. For this purpose, the fabrics that were already dyed with a natural dye source were once again dyed with two different natural dyes. In bottom dyeing (bottoming), fabrics were dyed with hops (Humulus lupulus L.) in the presence of different mordanting agents. Then the dyed, washed and dried samples were once again dyed (topping) with two different natural dye sources. For topping, powdered madder and acorn were tested in direct dyeing of wool samples. Finally, the colour changes were analysed with the use of a spectrophotometer. The study demonstrates that such a process (ie, bottoming with hops in the presence of different mordanting agents and then topping with madder or acorn) can be a way of obtaining different shades and colours with sufficient/good fastness values by natural dyeing.