The relationship between energy and production: Evidence from Turkish manufacturing industry

This paper investigates the relationship between energy and production at the industry level in an emerging market, Turkey, in a multivariate framework. The electricity consumption and value added relation is examined in the Turkish manufacturing industry, while also accounting for labor and fixed investment. We find that labor, fixed investment, electricity consumption, and value added are related via three cointegrating vectors. The VEC results indicate uni-directional causality running from electricity consumption to value added. Generalized impulse response and variance decomposition analyses confirm these results. Thus, energy input appears to be closely related to production. Hence, energy saving technologies and increased energy efficiency may increase the growth in manufacturing value added.     

A Simple,Low-Cost,and Useful Preconcentration Method for Quantification of Soluble,Insoluble, and Total Oxalate in Selected Vegetables Through Spectrophotometry

The amount of dietary oxalate from food may be an important risk factor in the development of idiopathic calcium oxalate nephrolithiasis. The main aim of this research was to develop an accurate and reliable method by cloud point extraction (CPE) combined with spectrophotometry to measure the oxalate contents of selected vegetables. The method is based on ion association of stable anionic complex, which is produced by the reaction of oxalate with Mo(VI), with Toluidine blue (TBH²⁺), and then by extraction into micelles of octylphenol ethoxylate (Triton X-45) in the presence of NH₄F as a salting-out agent at pH 6.0. Using the optimized conditions, the calibration graph was highly linear in the range of 1.2–240 μg L^?1. The detection limit of the method (LOD (3σ _blank/m) was 0.36 μg L^?1, and the relative standard deviation (RSD %) as a measure of precision was in the range of 1.1–5.3 % (n?=?5 for 5, 25, and 50 μg L^?1). The method was successfully applied to the speciative determination of soluble and total oxalate in vegetables after ultrasonic-assisted extraction and dilution at suitable ratios. The amount of insoluble oxalate was calculated from the analytical difference between total oxalate and soluble oxalate contents of samples with and without acidic extraction under ultrasonic power (300 W, 50 Hz) for 15 min at 60 °C. The accuracy of the method was intrinsically controlled and verified by comparing the results obtained with those of an independent kinetic method as well as recoveries of spiked samples.

Open image in new window

Graphical Abstract Experimental steps of the proposed method

     

Micellar sensitized catalytic kinetic spectrophotometry for highly accurate and reproducible determination of V（IV） and V（V）

A highly accurate and reproducible micellar sensitized kinetic method was proposed for determination of V（VI）. The method is based on its catalytic effect on the oxidation of Coomassie brilliant blue R 250 （CBB＋） by bromate at pH 2.0. The reaction was monitored spectro- photometrically by measuring absorbance change with a fixed-time method of 5 min at 594 and 552 nm with and without surfactant. The variables influencing the calibra- tion sensitivity were extensively investigated, and the optimal conditions were established. The linear calibration range was 10-1,600 μg.L-1 with a relative SD ranging from 0.35 % to 3.35 % （for five replicate measurements of 75, 500, 1,000, and 1,500 μg.L-1） and a detection limit of 3.8 μg.L-1. The selectivity was also investigated, and greatly enhanced by suitable masking agents. The method was successfully applied to the analysis of V（IV） in pre- sence of excess V（V） up to 25 fold in environmental waters with the recoveries of 100.0 %-102.8 % for V（IV） and 95.7 %-99.7 % for total V. Its accuracy was validated by analysis of certified reference material via the present kinetic method and standard flame atomic absorption spectrometric method after extractive preconcentration with good agreement between certified and found values.     

Thermodegradation of Poly(4-Vinylpyridine-co-Maleic Acid-co-Divinylbenzene) and N-oxide Derivatives: Modeling of TG and DTG Curves

Copolymer networks based on 4-vinylpyridine (4VPy)/maleic acid (MA)/divinylbenzene (DVB) and their N-oxide derivatives have been investigated by thermogravimetric analysis (TG) to evaluate their thermal stability in nitrogen atmosphere at fixed heating rate. Thermal stability was determined from TG curves to investigate the influence of 4VPy content and introduction of N-oxide groups. The TG and DTG curves of unmodified copolymers clearly show one thermodegradation stage and the same kinetic pathway. The decomposition temperatures do not depend on the 4VPy content. The copolymers modified by oxidation present lower thermostability than unmodified showing that the introduction of N-oxide groups modifies their kinetic pathways. A kinetic model Ozawa was used to determine the kinetic parameters. The apparent thermal decomposition activation energies (Δ E _d) of the unmodified copolymer under nitrogen was higher than that in modified copolymer.     

Determination of mechanical properties of glass‐epoxy composites in high temperatures

The objective of this study is to determine the tensile, compressive, and shear properties of unidirectional glass/epoxy composite plates under room (∼20°C) and high (40, 60, 80, and 100°C) temperatures. Mechanical properties were determined according to the ASTM standards. A hot lamination press was used for fabrication of composite plates. For curing process, laminated plates were retained at a constant pressure (250 kPa) and 120°C during 2 h. And then, composite plate is cooled to room temperature at the same pressure. The fiber volume fraction of laminated composite plate is measured as 65%. Experimental results show that the mechanical properties (except for the transverse tensile strength) of glass/epoxy composites are reduced by increasing temperature. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Fabrication of Mo-modified carbon felt as candidate substrate for electrolysis: Optimization of pH,current and metal amount

Mo was electrochemically deposited over a carbon felt (C) support in order to enhance hydrogen evolution activity of the support and make it a candidate for further modifications. For this aim, the effects of pH of deposition bath solution, deposition current and amount of deposited Mo were studied and optimized. Hydrogen evolution activity of the electrodes was evaluated in 1 M KOH solution with the help of electrochemical techniques. Surface structures of the electrodes were examined by scanning electron microscopy (SEM). It was found that 1 g Mo/g C modified electrode at pH 6 and 50 mA current exhibits the best hydrogen releasing performance. The enhanced current density at this electrode under ?1.60 V(Ag/AgCl) was 59.6% with respect to the bare support, which demonstrates that modifying the support by a thin Mo layer favors the hydrogen evolution reaction (HER) and reduces the energy requirement. The high hydrogen evolution performance of this modified substrate was assigned to its excellent structure, large surface area as well as high intrinsic catalytic activity of Mo. According to experimental findings, the Mo-modified C substrate was suggested for preparation of further modified electrode materials, especially with trace amounts of precious metals.     

A conceptual model for data management and distribution in peer-to-peer systems

While Peer-to-Peer (P2P) model gains significant attention in distributed computing, it is also expected to be a powerful model for information sharing. P2P systems are expected to provide exhaustive reliable computational resources and scalable accessibility. The data management and distribution in such systems requires storage, replication, data modeling, indexing, querying, retrieval, streaming, and topology management. While a lot of data management strategies have been proposed through the last years, these strategies have not been investigated with respect to a common model for P2P systems. However, since the services provided by the P2P systems are so diverse, it is very challenging to come up with a common layer-based model for all P2P systems. In this paper, we firstly propose a conceptual model for P2P systems, and then provide a classification and summary of data management and distribution strategies by referring to this model. The horizontal layers of the model correspond to modules of a P2P system whereas the columns are related to the services provided. The modules include base P2P service, storage, indexing, logical, service, and application modules. The services include security, querying, publish, join/leave, collaboration, and streaming. The paper concludes by providing a comprehensive list of data management and distribution strategies used in the existing P2P systems.     

Neural network aided design of Pt-Co-Ce/Al2O3 catalyst for selective CO oxidation in hydrogen-rich streams

In this study, the design of Pt-Co-Ce/Al₂O₃ catalyst for the low temperature CO oxidation in hydrogen streams was modeled using artificial neural networks. The effects of five design parameters, namely Pt wt.%, Co wt.%, Ce wt.%, calcination temperature and calcination time, on CO conversion were investigated by modeling the experimental data obtained in our laboratory for 30 catalysts. Although 30 points data set can be considered as small for the neural network modeling, the results were quite satisfactory apparently due to the fact that the experimental data generated with response surface method were well balanced over the experimental region and it was very suitable for neural network modeling. The success of neural network modeling was more apparent when the number of data points was increased to 120 by using the time on stream as another input parameter. It was then concluded that the neural network modeling can be very helpful to improve the experimental works in catalyst design and it may be combined with the statistical experimental design techniques so that the successful models can be constructed using relatively small number of data points.