Three-dimensional nickel nanodomes: Efficient electrocatalysts for water splitting

Highly efficient and stable three-dimensional (3D) Ni nanodome (Ni-NDs) arrays were fabricated as candidate cathode materials for alkaline water splitting. The NDs were prepared by a combined methods of soft lithography-nanosphere lithography, physical vapor deposition (PVD) and electrochemical deposition using polydimethylsiloxane (PDMS) as template. The water splitting activity of the 3D nanostructures were examined in 6 M KOH solution using polarization and electrochemical impedance spectroscopy techniques. The data obtained showed that well-structured and uniformly distributed Ni-NDs could be fabricated using this combined method. The ND arrays perform excellent hydrogen evolution activity with respect to Ni plate as a reference point since their nano-sized roughness results in larger real surface area. By comparing with Ni plate, lower hydrogen onset potential (85 mV) and charge transfer resistance (90.1%) as well as higher current density (90.4%) corresponding to the amount of evolved hydrogen were observed at the NDs. The Ni-NDs have high time-stability in the electrolysis conditions. It is believed that the Ni-ND arrays contribute to the design of novel electrocatalytic electrodes as candidate supporting materials.     

A microwave-induced plasma based on microstrip technology and its use for the atomic emission spectrometric determination of mercury with the aid of the cold-vapor technique

A new low-power, small-scale 2.45 GHz microwave plasma source at atmospheric pressure for atomic emission spectrometry based on microstrip technology is described. The MicroStrip Plasma (MSP) source was produced in microstrip technology on a fused-silica wafer and designed as an element-selective detector for miniaturized analytical applications. The electrodeless microwave-induced plasma (MIP) operates at microwave input power of 10-40 W and gas flows of 50-1000 mL.min-1 of Ar. Rotational (OH) and excitation (Fe) temperatures were found to be 650 and 8000 K, respectively. Spatially resolved measurements of the Hg I 253.7-nm atomic emission line with an electronic slitless spectrograph (ESS) showed that a cylindrically symmetric plasma with a diameter of about 1 mm is obtained. With the MSP, Hg could be determined by applying the flow injection cold vapor (FI-CV) technique with a detection limit of 50 pg.ml-1. In terms of the relative standard deviation, a time stability of < 1.4% for 45 replicates within 80 min can be realized at a concentration level of 10 ng.ml-1 of Hg. Hg could be determined in the leachate of a certified standard reference soil (STSD-4) obtained by treatment with aqua regia at the 930 +/- 76 ng.g-1 level. Results obtained by calibration with aqueous solutions of Hg and with standard addition were found to be in good agreement with those of cold-vapor atomic absorption spectrometry.     

Effects of chemical interesterification on solid fat content and slip melting point of fat/oil blends

Fat/oil blends, formulated by mixing fully hydrogenated palm oil stearin or palm oil stearin with vegetable oils (canola oil and cottonseed oil) in different ratios from 30:70 to 70:30 (w/w %), were subjected to chemical interesterification reactions on a laboratory scale. Fatty acid (FA) composition, iodine value, slip melting point (SMP) and solid fat content (SFC) of the starting blends were analysed and compared with those of the interesterified blends. SMPs of interesterified blends were decreased compared to starting blends because of extensive rearrangement of FAs among triacylglycerols. These changes in SMP were reflected in the SFCs of the blends after the interesterification. SFCs of the interesterified blends also decreased with respect to the starting blends, and the interesterified products were softer than starting blends. These interesterified blends can be used as an alternative to partial hydrogenation to produce a plastic fat phase that is suitable for the manufacture of margarines, shortenings and confectionary fats.     

Chemical Characteristics of Kavurma with Selected Condiments

A traditional meat product, kavurma, was prepared with the addition of various condiments (sage, thyme, ginger). The effects of condiments and storage time on thiobarbutiric acid (TBA) value, color attributes, pH, moisture, protein and fat contents of kavurma samples were investigated. Also, the effect of condiments on the sensory properties of samples was determined. The TBA values of condiments added samples were significantly lower than that of control. Ginger had a highest antioxidative activity and sensory scores compared to others samples. Color attributes generally decreased during storage and the additives differently affected the color of sample. The moisture content of samples was significantly affected from the condiments and storage period. Although sensory scores of the sample with condiments were higher than control, the difference was not statistically significant. It could be concluded that natural condiments could be used in kavurma production to improve quality characteristics of the product.     

Hole quality and interelectrode gap dynamics during pulse current electrochemical deep hole drilling

This paper presents the experimental investigation of pulse-current shaped-tube electrochemical deep hole drilling (PC-STED) of nickel-based superalloy. Influence of five process variables (voltage, tool feed rate, pulse on-time, duty cycle, and bare tip length of tool) on the responses, namely, depth-averaged radial overcut (DAROC), mass metal removal rate (MRR_g) and linear metal removal rate (MRR_l) have been discussed. Mathematical models have been developed to express the effects of the process parameters on DAROC, MRR_g and MRR_l. The proposed model permits quantitative evaluation of the hole quality and process performance simultaneously. The results have been confirmed for the profile of the drilled hole and MRR_l obtained experimentally. In all the experiments, through holes of 26 mm depth and diameters ranging from 2.205 mm to 3.279 mm were drilled. The results have been explained by the interelectrode gap dynamics prevailing during pulse electrochemical deep hole drilling. Optimum parameters determined from these experiments can be used to efficiently drill high-quality deep holes of high aspect ratio in nickel-based superalloys.     

Investigation of structural properties of clinoptilolite rich zeolites in simulated digestion conditions and their cytotoxicity against Caco-2 cells in vitro

The use of the clinoptilolite rich natural zeolites in biomedical applications such as in anticancer therapy, drug or drug support systems and as nutritive supplement is highly dependent on their behavior in digestive conditions. Aim of this study is to investigate structural stability of clinoptilolite rich natural zeolites in simulated digestion conditions and their interactions with digestive media and with Caco-2 (human colon adenocarcinoma) cells. X-ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Scanning Electron Microscopy (SEM) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analyses of the clinoptilolite rich zeolite samples showed that zeolites preserved their structural stabilities during in vitro digestion. Slight interactions were detected in UV measurements of the digestive liquid media and FTIR spectra of the intestinal digested media powders. SEM results implied that zeolites might have a role in the aggregation of the digestive enzymes. Cytotoxicity test using colon cancer cells showed that clinoptilolite rich natural zeolites have cytotoxic effect against Caco-2 cells and cytotoxicity did not significantly change with respect to simulated digestion process.     

Removal of bacteria by clinoptilolite rich mineral and its surfactant modified forms

Batch experiments were carried out to understand the potential values of clinoptilolite rich mineral and its surfactant modified forms in the removal of Gram-positive and Gram-negative bacteria. Zeta potential and Fourier Transform IR analysis were performed to explain the possible interactions between the bacteria and the zeolite samples. The results revealed that hydrogen bonding was significant mechanism in the removal of bacteria with clinoptilolite rich mineral and anionic surfactant modified clinoptilolite rich mineral whereas both attractive electrostatic forces and hydrogen bonding were dominant mechanism in the removal of bacteria with cationic surfactant modified clinoptilolite rich mineral. Cationic and anionic surfactant modified clinoptilolite rich mineral are promising materials in removal of bacteria studies.     

Breakthrough Curves Analysis and Statistical Design of Phenol Adsorption on Activated Carbon

Activated carbon was used as an adsorbent for the removal of phenol from aqueous solution under various operating conditions. Statistical design using MATLAB® tools was employed to study the effects of three variables on six different response factors. MATLAB® software was employed to solve proposed quadratic model equations and for fitting a quadratic response surface. All the models with a very high adjusted R‐square predicted the experimental data well. The Thomas, the Yoon‐Nelson, the Wolborska, the bed depth service time, and the linear driving force models were used to predict breakthrough curves for experimental data. The results showed that the linear driving force model was suitable for the prediction of the breakthrough curve data.     

Transcatheter closure of patent ductus arteriosus using controlled-release coils

Controlled-release coils have become available recently for the closure of patent ductus arteriosus (PDA). Transcatheter closure of patent arterial ducts was attempted in 13 patients, ranging in age from 5 months to 15 years, mean 4.1 years. Implantation of controlled-release PDA coils was attempted via the femoral artery through 5 Fr catheters in all cases except one, in whom both the femoral arterial and venous routes were used. The procedure was successful in 10 of the 13 patients. In these, the pulmonary artery systolic pressure ranged between 25 and 42 mmHg and the duct diameter varied from 1.5 to 6 mm at its narrowest point. Six of the patients received a single coil. Two coils were inserted in three patients and three coils in one patient. In three patients the ducts were too large for safe release of the coils, despite attempted implantation of up to three coils simultaneously. These coils were easily withdrawn into the catheter. Immediately at the end of the procedure, the duct was completely occluded in nine of the 10 patients, and in one patient there was a small residual flow. The procedure time varied between 35 min and 2.5 h, mean 81 min and the fluoroscopy time varied from 5 to 78 min, mean 25 min. None of the patients experienced hemorrhage, diminished lower extremity pulse, hemolysis or infection. In one patient, a 5 mm coil embolized into the right pulmonary artery soon after release. It was retrieved with a snare, then 8 mm and a 5 mm coil were implanted satisfactorily in the arterial duct. At follow-up by color Doppler echocardiography, the duct was completely occluded in all patients. Transcatheter closure of patent arterial ducts by controlled-release PDA coils is effective and safe. Even when more than one coil is inserted, it is still cheaper than transcatheter umbrella closure. This method is therefore of great value, particularly in less affluent countries.