Synthesizing hydrogen from ammonia over Ru incorporated SiO2 type nanocomposite catalysts

In this study, Ruthenium incorporated SiO₂ type nanocomposite catalysts were prepared for CO_x free hydrogen production by using one-pot hydrothermal synthesis procedure. Experiments which were carried out under the flow of pure ammonia (300 ml/min) presented that 86% ammonia conversion was obtained at 500 °C over the catalyst having Ru/Si molar ratio of 0.060. Using promoter in the preparation of catalyst enhanced the catalytic activity especially for the ones prepared at low ruthenium loadings. While the catalyst that was prepared at a Ru/Si molar ratio of 0.010 without promoter gave negligible activity at 500 °C, the promoted one gave 33% conversion at 500 °C and 73% at 600 °C. Experiments were also repeated with lower feed flow rate values of ammonia such as 60 ml/min and 5 ml/min. It was seen that catalyst prepared at a Ru/Si molar ratio of 0.010 with promoter gave conversion value over 80% at 400 °C under the feed flow rate of 5 ml/min.     

Antioxidant activity and phenolic compounds of ginger (<Emphasis Type="Italic">Zingiber officinale</Emphasis> Rosc.) determined by HPLC-MS/MS

Oxidative stress related diseases often arise from over production of free radicals and reactive oxygen/nitrogen species. The prevention of these diseases could be possible with the use of natural antioxidant plants that could be promising as therapeutic candidates. Since antioxidant properties of a species could be stem from phenolic compounds, it is, therefore, important to evaluate antioxidant and total/individual phenolic and flavonoid content. For this purpose, we evaluated antioxidant properties of ginger (Zingiber officinale Rosc.) based on three parameters: the antioxidant capacity, total phenolic and flavonoid content as well as identification of phenolic acids of water extract (WEG) and ethanol extract (EEG) of ginger. For antioxidant capacity, we performed FRAP, CUPRAC assay, Fe²⁺ chelating ability, DPPH and DMPD radical scavenging activities. Also, total phenolic and flavonoid contents in both extracts were also measured via Folin Ciocalteu’s method. For identification of phenolic acids, HPLC-MS/MS method was performed. The results showed that EEG had generally better antioxidant activity than WEG in all assays. HPLC-MS/MS analysis showed that there are at least eight different phenolic acids found in ginger, among which pyrogallol p-hydroxybenzoic acid, ferulic acid and p-coumaric acid were more abundant in both extracts. This study clearly showed that ginger extracts demonstrated effective antioxidant properties and their consumption may reduce or delay the progression of diseases that oxidative stress take place due to lack of antioxidant supplementation.     

Sulphur in Turkish lignites and possible remedies

Lignites are the largest and most important solid fuels of Turkey. The high sulphur content of these fuels, their low calorific value and high ash content pose problems in their use. The organic sulphur content is generally over 5% in Turkish lignites, which makes simple technologies, such as washing and flotation, unapplicable. Pyrolysis, wet chemical desulphurisation and biochemical desulphurisation technologies are either not capable of reducing the sulphur to desired limits, or uneconomical. Overall, the most promising technology in overcoming the sulphur problem in Turkish lignites seems to be fluidised bed combustion.     

Novel membranes based on poly(5‐(methacrylamido)tetrazole) and sulfonated polysulfone for proton exchange membrane fuel cells

Proton‐exchange membrane fuel cells (PEMFC)s are increasingly regarded as promising environmentally benign power sources. Heterocyclic molecules are commonly used in the proton conducting membranes as dopant or polymer side group due to their high proton transfer ability. In this study, 5‐(methacrylamido)tetrazole monomer, prepared by the reaction of methacryloyl chloride with 5‐aminotetrazole, was polymerized via conventional free radical mechanism to achieve poly(5‐(methacrylamido)tetrazole) homopolymer. Novel composite membranes, SPSU‐PMTetX, were successfully produced by incorporating sulfonated polysulfone (SPSU) into poly(5‐(methacrylamido)tetrazole) (PMTet). The sulfonation of polysulfone was performed with trimethylsilyl chlorosulfonate and high degree of sulfonation (140%) was obtained. The homopolymers and composite membranes have been characterized by NMR, FTIR, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). ¹H‐NMR and FTIR confirmed the sulfonation of PSU and the ionic interaction between sulfonic acid and poly(5‐(methacrylamido)tetrazole) units. TGA showed that the polymer electrolyte membranes are thermally stable up to ～190°C. Scanning electron microscopy analysis indicated the homogeneity of the membranes. This result was also supported by the appearance of a single T_g in the DSC curves of the blends. Water uptake and proton conductivity measurements were, as well, carried out. Methanol permeability measurements showed that the composite membranes have similar methanol permeability values with Nafion 112. The maximum proton conductivity of anhydrous SPSU‐PMTet0.5 at 150°C was determined as 2.2 × 10^?6 S cm^?1 while in humidified conditions at 20°C a value of 6 × 10^?3 S cm^?1 was found for SPSU‐PMTet2. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40107.     

Numerical Calculation of Trapped Magnetic Field for Single and Multiple Bulk Superconductors

In this work, the trapped magnetic field was calculated using the sand-pile model and Biot–Savart law. The numerical simulation of the trapped magnetic field was performed varying the sample shape and dimensions, distance between the sample surface and observation point. In addition, the magnetic field characteristics of superconducting bulk arrangement in an array was determined. The trapped magnetic field was found to be depending on the sample shape and dimensions and distance between the sample and observation point. It is observed that, when the distance from the surface is larger, the value of the trapped magnetic field decreases, but the variation of the trapped magnetic field becomes small due to averaging the distribution of the trapped magnetic field.     

The Effect of Excess Y<Subscript>2</Subscript>O<Subscript>3</Subscript> Addition on the Mechanical Properties of Melt-Processed YBCO Superconductor

In this study, two kinds of melt-processed YBCO samples with Y₂O₃ addition were fabricated and their microstructures were defined by XRD analysis and polarized light optical microscopy. The mechanical properties of these compounds have been investigated by measuring the Vickers hardness. The superconducting transition temperature was determined by inductive measurements for oxygenated and non-oxygenated samples. The compacted powders were located on a crucible with a buffer layer of Y₂O₃ and a crucible with Y₂O₃ powder freely poured to avoid liquid to spread on the furnace plate. It was found that the sample located on crucible with freely poured Y₂O₃ powder has shown almost single crystal and indicated a very sharp transition curve.     

Scheduling continuous aluminium casting lines

This study considers the problem of scheduling casting lines of an aluminium casting and processing plant. In aluminium processing plants, continuous casting lines are the bottleneck resources, i.e. factory throughput is limited by the amount of aluminium that can be cast. The throughput of a casting line might be increased by minimizing total setup time between jobs. The objective is to minimize setup time on production lines for a given time period while balancing workload between production lines to accommodate potential new orders. A mathematical formulation for scheduling jobs to minimize the total setup time while achieving workload balance between the production lines is presented. Since the casting scheduling problem is an NP-hard problem, even with only one casting line, a four-step algorithm to find good solutions in a reasonable amount of time is proposed. In this process, a set of asymmetric travelling salesman problems is followed by a pairwise exchange heuristic. The proposed procedure is applied to a case study using real casting data.     

A simple method for weight estimation of whole herring (Clupea harengus) using planar X-ray imaging

Fish weight is one of the key parameters used in commercial sorting of fresh fish. The capability of on-line and accurate estimation of the weight of each individual fish has a direct impact on profitability for the fish processors. Planar X-ray images of whole herring (n=16) were taken using a commercial medical X-ray apparatus. The integral intensity of all pixels in each image was calculated and correlated with the weight of the respective fish producing a linear relationship with a high correlation factor (R2=0.992) and a calculated mean prediction error of 2.5%. Planar X-ray imaging combined with simple image processing was successfully used to predict weight of whole herring. The technique has a potential to be used industrially for on-line weight estimation in sorting/grading systems.     

On some difference sequence spaces of fuzzy numbers

In this paper, using the difference operator of order m and a lacunary sequence \(\theta = (k_{r})\), we introduce and examine some classes of sequences of fuzzy numbers. Furthermore, we study some of their properties like completeness, solidity, symmetricity and convergence free. We also give some inclusion relations related to these classes.