Selective removal of Cr(VI) ions from aqueous solutions including Cr(VI), Cu(II) and Cd(II) ions by 4-vinly pyridine/2-hydroxyethylmethacrylate monomer mixture grafted poly(ethylene terephthalate) fiber

In this study, a new reactively fibrous adsorbent was prepared by grafting 4-vinly pyridine (4-VP) and 2-hydroxyethylmethacrylate (HEMA) monomer mixture onto poly(ethylene terephthalate) (PET) fibers for removal of Cr(VI), Cu(II) and Cd(II) metal ions from aqueous solution by using batch adsorption method. The influence of various parameters such as graft yield (GY), pH, adsorption time, initial ion concentration and adsorption temperature was investigated. The selectivity of the reactive fiber was also examined. The results show that the adsorbed amount of metal ions followed as given in the order Cr(VI) > Cd(II) > Cu(II). At pH 3, Cr(VI) was removed by 99% while the initial concentration of ions was at 5 mg L⁻¹ and by 94% at 400 mg L⁻¹. It was found that the grafted fiber is more selective for Cr(VI) ions in the mixed solution of Cr(VI)–Cu(II), Cr(VI)–Cd(II) and Cr(VI)–Cu(II)–Cd(II) at pH 3 and it was observed that the grafted fibers are stable and regenerable by acid and base without losing their activity.     

Microbial source tracking using host specific FAME profiles of fecal coliforms

The objective of this study was to investigate the host-specific differences in fatty acid methyl ester (FAME) profiles of fecal coliforms (FC). A known-source library was constructed with 314 FC isolates cultured from 6 possible sources of fecal pollution; 99 isolates from sewage; 29 from bovine; 29 from poultry; 50 from swine; 46 from waterfowl; and 61 from deer. It was found that the hydroxy FAMEs 12:0 2 OH, 12:03 OH, and 14:02 OH were exclusively associated with isolates of human origin. On the other hand, 3 saturated FAMEs, 10:0, 15:0, and 18:0 were found only in isolates from non-human sources, 15:0 being associated with livestock samples only. In addition to the presence of these signature FAMEs, the mean relative masses of 16:1 omega7c and 16:1 ISO/14:03 OH were significantly different between the isolates of human and non-human origins. A linear discriminant function differentiated FC isolates of human origin from those of livestock and wildlife origin at 99% accuracy. These results strongly suggest that the FAME profiles of FC show statistically significant host specificity and may have the potential to be used as a phenotypic microbial source tracking tool.     

Investigation of combustion and emission characteristics in a TBC diesel engine fuelled with CH4–CO2–H2 mixtures

In this study, an experimental investigation was performed to reveal combustion and emission characteristics of common-rail four-cylinder diesel engine run with CH₄, CO₂ and H₂ mixtures. The engine pistons were thermally coated with zirconia and Ni–Al bond coat by plasma spray method. With a small amount of the pilot diesel, port fuelled methane (100% CH₄), synthetic biogas (80% CH₄ + 20% CO₂), and hydrogen presented (80% CH₄+10% CO₂+10% H₂) mixtures were used as main fuel at different loads (50 Nm, 75 Nm, and 100 Nm) at a constant speed of 1750 min^?1. Comparative analysis of the combustion (cylinder pressure, PRR, HRR, CHR, ringing intensity, CA10, CA50, and CA90), BSFC, and emissions (CO₂, HC, NO_x, smoke, and oxygen) at the various engine loads with and without piston coating was made for all fuel combinations. It was found that coating the engine pistons enhanced the examining combustion characteristics, whereas it slightly changed BSFC and most of the emissions. As compared to the sole diesel fuel, the gaseous fuel operations showed higher in-cylinder pressure, PRR, and ringing intensity values, earlier combustion starting and CAs, and lower diesel injection pressure at the same engine operating conditions. Dramatic increase in the ringing intensity was particularly found by the hydrogen introduced mixture under the tests with coated piston. HC and CO₂ emissions increased in operation with the synthetic biogas; however, hydrogen introduction reduced HC emissions by 4.97–30.92%, and CO₂ emissions by 5.16–10%.     

Influence of leather meal fertilizer on soil organic matter: A laboratory study

Leather meal fertilizer was mixed with a soil (Typic Xerorthent) and incubated in the laboratory for one year at room temperature. Soil samples were collected periodically and analyzed in order to follow the transformation of the organic matter as well as the availability of Cr and certain plant nutrients.The results obtained showed intense mineralization during the first 60–120 days of the incubation period. The amount of humic acids (HAs) separated from the alkaline extracts showed that the humification level increased markedly after the first 60 days of incubation and, as shown by IEF analysis, organic compounds similar to the soil humic substances were formed.Variations in the amount of available nutrients were observed; only the extractable Cr increased during the first period of mineralization.     

Identification of blood meal in fertilizers

A simple and useful analytical method is proposed for the characterization of blood meal fertilizer, a quality organic fertilizer commonly used in agriculture. Despite the agronomical and commercial importance of this organic fertilizer, Italian law does not indicate an analytical method for its identification in organic matrices. This situation is very unsatisfactory because unscrupulous producers could declare the presence of a quality organic fertilizer, such as blood meal, instead of a poorer fertilizer. In this work the heme group of the hemoglobin contained in blood meal was characterized spectrophotometrically and a calibration curve prepared using different concentrations of hemoglobin was used to determine the hemoglobin content in six blood meal samples. The method was successfully applied for the qualitative identification of hemoglobin in mixtures of organic and/or organic fertilizers with small amounts (3–10%) of blood meal.     

Overview of Compaction Data Analysis Techniques

In this review article, the techniques that have been utilized to assess the compactional behaviour of pharmaceutical materials were presented, and the advantages, limitations and modifications of some of these methods were discussed. It was concluded that despite some of these techniques, such as Heckel equation, F-D curves, energy of compaction, tensile strength and hardness measurements, have received considerable attention, none of them was found to be satisfactory for the comprehensive analysis of the mechanisms involved in the compaction of the solid particulate matter.     

Formulation and Compaction of Microspheres

The factors affecting the tabletability of formulations containing uncoated and/or coated microspheres were discussed by presenting a case study. The size and shape, as well as surface properties of microspherical particles, the type and amount of coating agent, selection of the external additives, and the rate and magnitude of the pressure applied were found to be the most critical factors to be considered in order to obtain and maintain the desired drug release properties of the microspheres. It was found that microcrystalline cellulose was needed in order to produce satisfactory beads in terms of size, shape and surface characteristics. The microsphere formulations, which were found to be highly sensitive to lubrication, were more compressible than their powder forms, but produced much weaker tablets. When coated with Surelease, increasing the amount of coating on the pellets reduced the tensile strength of their compacts. Compaction of the microspheres at high velocities resulted in a decrease in the tensile strength values and an increase in the volumetric strain recovery values. Dissoultion studies revealed that, regardless of the amount of coating applied, the coated microspheres lost their sustained release properties during compaction.     

A new feature extraction approach based on one dimensional gray level co-occurrence matrices for bearing fault classification

ABSTRACT

Recently, precise and deterministic feature extraction is one of the current research topics for bearing fault diagnosis. For this aim, an experimental bearing test setup was created in this study. In this setup, vibration signals were obtained from the bearings on which artificial faults were generated in specific sizes. A new feature extraction method based on co-occurrence matrices for bearing vibration signals was proposed instead of the conventional feature extraction methods, as in the literature. The One (1) Dimensional–Local Binary Patterns (1D-LBP) method was first applied to bearing vibration signals, and a new signal whose values ranged between 0–255 was obtained. Then, co-occurrence matrices were obtained from these signals. The correlation, energy, homogeneity, and contrast features were extracted from these matrices. Different machine learning methods were employed with these features to carry out the classification process. Three different data sets were used to test the proposed approach. As a result of analysing the signals with the proposed model, the success rate is 87.50% for dataset1 (different speed), 96.5% for dataset2 (fault size (mm)) and 99.30% for dataset3 (fault type – inner ring, outer ring, ball) was found, respectively.     

A systematic design of 1.5–9 GHz high power–high efficiency two‐stage GaAs PHEMT power amplifier

In this article, a systematic design approach for a Class‐A operated wideband power amplifier is presented. The power amplifier structure comprises of two transistors in the cascaded single stage traveling wave amplifier topology. A power amplifier was designed by using the systematic approach and fabricated with 0.25 μm GaAs PHEMT MMIC process. The amplifier has an area of 3.4 × 1.4 mm². Measurement results show that almost flat gain performance is obtained around 15 dB over 1.5–9 GHz operating bandwidth. In most of the band, with the help of a wideband load‐pull matching technique, the amplifier delivers P_o,sat and P_o,1dB of around 30 dBm and 28 dBm where the corresponding power added efficiencies are >50% and >36%, respectively. It is shown that the proposed design approach has the advantage of simple and systematic design flow and it helps to realize step‐by‐step design for the designers. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:615–622, 2014.