The kinetics of the gaseous extraction of gallium from mica

The gaseous reduction of gallium in white mica has been studied using natural gas as the reducing gas. From a study at three temperatures, the initial extraction was observed to be linear with time and independent of particle size. The results suggest that delamination of the mica lattice is important. The measured activation energy for the loss of gallium from the white mica is 184 × 21 kJ mol^?1.     

Anthocyanin-rich fruit vinegar from Grewia and Cantaloupe fruit blends

Grewia is a tropical berry rich in anthocyanins and antioxidants but highly perishable in nature. In this study, desirable composite blend of overripe Grewia (Phalsa) berries and cantaloupe was sought for conversion to acetic acid. Composition of raw macerate, and the alcoholic and acetic ferments was analysed for sugars, alcohol and acetic acid. The primary alcohol yield varied significantly (5.75–99.44%) with blend composition. Vinegar from select blend attained 4.98% acidity with 138.57 mg mL⁻¹ of phenols and high anthocyanins retention (74.77%). Gompertz model was used to fit the growth curves of S. cerevisiae and A. aceti (R²> 0.92) during fermentation. Presence of ethyl acetate, iso-pentyl alcohols explained pleasant sweet fruity aroma of resulting vinegar. Thus, high quality functional red fruit vinegar can be obtained to prevent spoilage and utilise the functional potential of this delicate and nutritious berry.     

Effect of Temperature and Amount of Flux in a Charge on Structure and Phase Composition of Balkhash Copper Smelter Plant Slags

Metallurgist - Samples of converter slag of the Balkhash copper-smelting plant (BMZ), taken during their discharge from a converter, and experimental samples after conversion under laboratory...     

An equi-biased <Emphasis Type="Italic">k</Emphasis>-prototypes algorithm for clustering mixed-type data

Clustering has been recognized as a very important approach for data analysis that partitions the data according to some (dis)similarity criterion. In recent years, the problem of clustering mixed-type data has attracted many researchers. The k-prototypes algorithm is well known for its scalability in this respect. In this paper, the limitations of dissimilarity coefficient used in the k-prototypes algorithm are discussed with some illustrative examples. We propose a new hybrid dissimilarity coefficient for k-prototypes algorithm, which can be applied to the data with numerical, categorical and mixed attributes. Besides retaining the scalability of the k-prototypes algorithm in our method, the dissimilarity functions for either-type attributes are defined on the same scale with respect to their dimensionality, which is very beneficial to improve the efficiency of clustering result. The efficacy of our method is shown by experiments on real and synthetic data sets.     

A literature review on planning and analysis of accelerated testing for reliability assessment

Accelerated testing has been widely used for several decades. Started with accelerated life tests with constant‐stress loadings, more interest has been focused prominently on accelerated degradation tests and time‐varying stress loadings. Because accelerated testing is crucial to the assessment of product reliability and the design of warranty policy, it is important to develop an efficacious test plan that encompasses and addresses important issues, such as design of stress profiles, sample allocation, test duration, measurement frequency, and budget constraint. In recent years, extensive research has been conducted on the optimal design of accelerated testing plans, and the consideration of multiple stresses with interactions has become a big challenge in such experimental designs. The purpose of this study is to provide a comprehensive review of important methods for statistical inference and optimal design of accelerated testing plans by compiling the existing body of knowledge in the area of accelerated testing. In this work, different types of test planning strategies are categorized, and their drawbacks and the research trends are provided to assist researchers and practitioners in conducting new research in this area.     

Differential scanning calorimetry studies on coal. 1. Pyrolysis in an inert atmosphere

Results of thermal changes involved during the pyrolysis of twelve US coals of various ranks in a helium atmosphere at 5.6 MPa (gauge) and temperatures up to 580 °C are reported. Thermal effects during pyrolysis of coals ranging in rank from anthracite to HVC bituminous are endothermic in nature over the temperature range investigated. Exothermic heats are observed only in the case of sub-bituminous and lignitic coals. The net thermal effects, that is the resultant of endothermic and exothermic heats, go from endothermic to exothermic with increase in carbon content, a transition occurring around 66% carbon and another in the reverse direction at about 75% carbon. A maximum in exothermicity occurs around 71% carbon and in endothermicity at about 81% carbon. Results have been compared with published DTA data on coals. The fallacy in the interpretation of published DTA thermograms of coals, where weight changes accompany thermal effects, is discussed.     

Lead-strontium titanate glass ceramics: I – crystallization and microstructure

The crystallization behaviour of glasses in the system [(Pb Sr ) O·TiO₂]-[2SiO₂· B₂O₃]-[K₂O]-[BaO] (0.2 ≤ x ≤ 0.9) have been studied. Perovskite titanate was found to be the major phase in all the glass ceramic samples investigated. The actual composition of crystalline phases could not be confirmed on the basis of shift in the X-ray diffraction (XRD) peak positions because of similar effects due to solid solution formation and strain due to crystal clamping. Comparison of the observed intensities of various XRD peaks of the perovskite titanate phase with the calculated intensities for (Pb Sr )TiO₃ with same lead/strontium ratio confirmed the formation of lead strontium titanate solid solution. Microstructural characteristics of various glass ceramics are also discussed. The advantages of using K₂O and BaO as additives instead of only K₂O are also discussed.     

Amine-functionalized sol-gel-based lab-in-a-pipet-tip approach for the fast enrichment and specific purification of phosphopeptides in MALDI-MS applications

Amine-functionalized sol-gels were investigated for the enrichment and purification of phosphopeptides from digested protein mixture solutions. Tetramethylorthosilicate (TMOS) and N'[3-(trimethoxysilyl)-propyl]-diethylenetriamine (TPDA) were used in a 1:1 mole ratio in the production of amine-functionalized sol-gels. The sol-gel network was then used for phosphopeptide enrichment. Phosphopeptide enrichment onto the synthesized amine-functionalized sol-gels was performed using an enolase digested peptide mixture, a β-casein digested peptide mixture, as well as these digested peptide mixtures contaminated 50-fold with bovine serum albumin (BSA). Moreover, phosphopeptide enrichment was successfully performed using nonfat milk as a highly contaminated and complex material. In each phosphopeptide enrichment and purification process, only phosphopeptides were enriched and separated from the other digested peptides. Phosphopeptides were adsorbed onto the amine-functionalized sol-gels at pH 4.0 and eluted at pH 1.0 using trifluoroacetic acid (TFA). For phosphopeptide analysis by MALDI-MS, a 2,5-dihydroxybenzoic acid matrix containing 1.0% phosphoric acid was used to overcome the degradation of phosphopeptides and provide high intensity phosphopeptide protonated molecular ion signal intensities. It was also found that phosphopeptide detection limits were improved to approximately 10 femtomoles. For rapid and specific phosphopeptide enrichment and purification, sol-gel materials were placed in a 10 μL pipet tip with glass wool on either side. Phosphopeptide enrichment from digested peptide mixtures was performed in a very short time (less than 1 min) at subpicomole levels using this novel lab-in-a-pipet-tip approach.     

Morphology and structural properties of pH-responsive amphiphilic peptides

Protein nanomaterials at the peptide level have shown great potential for medical applications. Peptides change their morphological conformation because of changes in self-assembly properties when they are exposed to changes in solvent composition or pH. Two 15-residue peptide sequences, KhK (KKKFLIVIGSIIKKK) and Alternating Kh (KFLKKIVKIGKKSII), were designed for the purpose of determining the role of peptide sequence on solution morphology and conformation. KhK solutions exhibited a random coil to helical transition when solvent conditions were changed from water to a trifluorethanol/water solution at acidic pH. Alternating Kh solutions, however, demonstrated primarily random coil character under similar solvent and pH conditions as determined by circular dichroism spectroscopy and 2D-1H-1H nuclear magnetic resonance spectroscopy. At basic pH, circular dichroism spectroscopy and nuclear magnetic resonance spectroscopy analysis demonstrated that random coil character increased at basic pH for KhK, whereas Alternating Kh exhibited an increase in beta-sheet character. Further analysis by transmission electron microscopy showed marked differences in the peptide solution morphology. Peptide particle aggregation and fiber formation were significantly affected by solvent composition and pH values for both peptide sequences.