Chemometric approach to validating faecal sterols as source tracer for faecal contamination in water

Faecal sterols detection is a promising method for identifying sources of faecal pollution. In this study, faecal contamination in water samples from point source (sewage treatment plants, chicken farms, quail farms and horse stables) was extracted using the solid phase extraction (SPE) technique. Faecal sterols (coprostanol, cholesterol, stigmasterol, β-sitosterol and stigmastanol) were selected as parameters to differentiate the source of faecal pollution. The results indicated that coprostanol, cholesterol and β-sitosterol were the most significant parameters that can be used as source tracers for faecal contamination. Chemometric techniques, such as cluster analysis, principal component analysis and discriminant analysis were applied to the data set on faecal contamination in water from various pollution sources in order to validate the faecal sterols’ profiles. Cluster analysis generated three clusters: coprostanol was in cluster 1, cholesterol and β-sitosterol formed cluster 2, while cluster 3 contained stigmasterol and stigmastanol. Discriminant analysis suggested that coprostanol, cholesterol and β-sitosterol were the most significant parameters to discriminate between the faecal pollution source. The use of chemometric techniques provides useful and promising indicators in tracing the source of faecal contamination.     

Carbon dioxide induced degradation of diethanolamine during absorption and desorption processes

Alkanolamines are widely used in the purification of the sourgas sweetening process. During the sour gas absorption process, CO_2 significantly degrades the amine solvent and creates enormous problems for plant operation. In this work, CO_2 induced degradation of aqueous diethanolamine(DEA) solution was conducted in a 1.25 L jacketed glass reactor that functioned as an absorber and stripper at atmospheric conditions. Pure CO_2 was bubbled through the reactor until the solution became saturated. In this study, the concentrations of DEA used were in the range of concentrations between 2 mol·L~(-1) and 4 mol·L~(-1). In the degradation experiment, six generic cycles were conducted for each run. Each cycle was configured with the absorption and desorption of carbon dioxide at 55 ℃ and 100 ℃, respectively. Samples were collected after a predetermined experimental time and analyzed by ion chromatography(IC) to identify unknown ionic degradation products(DGPs). In the IC analysis, three different columns were used for anion, cation and ion exclusion systems, which are Metrosep A Supp 5150/4.0, Metrosep C Supp 4 150/4.0 and Metrosep Organic Acids, respectively. The major identified DGPs of D01 DEA2 M, D02 DEA3 M, and D03 DEA4 M are nitrite, acetate and ammonium. Phosphate product was found in the degraded amine samples which might be due to the contamination of water or chromatographic system.     

LBTM: A lightweight blockchain-based trust management system for social internet of things

The Journal of Supercomputing - In order for the Internet of things to facilitate information sharing, the technology needs trustworthy mechanisms to ensure safe communications and reliable...     

Effect of storage time on the microbial,physicochemical and sensory characteristics of ovine whey-based fruit beverages

The aim of this study was to establish the physicochemical, sensory and microbiological quality of ovine whey-based fruit beverages produced from pasteurised ovine whey (mango flavoured–sugar sweetened [M-Su], pineapple flavoured–extra sugar sweetened [P-ESu], and tropical fruit flavoured–stevia sweetened [T-St]), and the changes in quality of these beverage types during the 15-day storage. The beverages were evaluated for their pH, colour, sediment and particle size distribution, microbiological count and sensory quality. No significant differences in the pH and the microbial counts among the beverages were noted during the storage period; however, the particle size distribution reflected the sediment formation that significantly decreased during the same period in all beverage types. The beverages were getting lighter during storage, which was evident by increasing L* and decreasing a* values for colour. All three beverage types had very high scores for taste and odour after 9 days, and colour and sediment after 5 days of storage. Beverage-type T-St was most preferred by consumers, with the highest scores for taste, odour and sensory appearance. These results can assist in the better determination of the deteriorative changes in a variety of ovine whey-based beverages, necessary changes in product composition that might result in improved product quality, and yet reducing losses incurred during ovine milk processing. In this sense, this research's findings contribute to the utilisation of whey beverages by the dairy industry to the development of functional products.     

Production of Palm-Based Esteramine Through Heterogeneous Catalysis

This study involved maximizing the conversion of palm‐based methyl palmitate to esteramine, an intermediate for esterquats via transesterification with triethanolamine, aided by Ca–Al as a heterogeneous catalyst in a 500‐ml reaction unit. The effect of process parameters on the conversion was investigated. The optimum process parameters, consisting of a mole ratio of 1.8:1 (methyl palmitate:triethanolamine), 170 °C, 10 mbar, 0.5 % catalyst and a duration of 2 h, produced more than 90 % conversion. Transesterification employing Ca–Al is more environmentally friendly than the conventional approach using sodium methoxide, simplifies the downstream separation process and the reusability of the catalyst was successfully tested in three subsequent cycles.     

Modeling and kinetics study of conventional and assisted batch solvent extraction

Batch solvent extraction techniques have been widely explored. On understanding its potential significance, this article aims to review kinetics and modeling of various extraction techniques which involve assisted means including microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), pulse electric field (PEF) and high voltage electrical discharge (HVED). This review includes a detailed discussion of the instrumental setup, extraction mechanisms and their distinct advantages and disadvantages. Additionally, the impact of the operating parameters on the extraction kinetics of the mentioned techniques are highlighted. The review also covers the mathematical modeling based on Fick's law, chemical rate law and empirical models. The established kinetic models of various extractions are also summarized to facilitate better understanding.     

Surface modification of alumina with biosafe molecules: Nanostructure,thermal, and mechanical properties of PVA nanocomposites

In this investigation, citric acid (CA) and ascorbic acid (AA) as biocompatible and biodegradable coupling agents were grafted onto surface of Al₂O₃ nanoparticles (NP)s via ultrasonic process. Then, various percentages of the modified Al₂O₃ NP were immobilized onto matrix of pristine poly(vinyl alcohol) (PVA) and ameliorated their morphology, mechanical and thermal properties. Transmission electron microscopy photographs were valid criterion for characterizing morphology of Al₂O₃ with CA and AA. The improvement of the mechanical properties revealed good dispersion of the modified Al₂O₃ into the matrix of PVA. Finally, thermogravimetric analysis curves displayed an increase in the thermal stability of the nanocomposites upon grafting of the modified Al₂O₃. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44561.     

Potentially probiotic acetic acid bacteria isolation and identification from traditional dairies microbiota

Among probiotics, acetic acid bacteria (AAB) can be used as preservative agents because of their high fermentation and acidification activities. This study aimed to isolate, identify and biologically characterise Acetobacter strains from traditional Iranian dairy products. Acetobacter strains were identified by catalase assay, Gram staining, and combined repetitive sequence‐based PCR [(GTG)₅‐PCR fingerprints] and 16S rDNA gene sequencing. We identified eight strains belonging to four species, including Acetobacter aceti, Acetobacter indonesiensis, Acetobacter cibinongensis and Acetobacter syzygii. The molecular techniques could be used as an effective and rapid alternative tool to identify and characterise dairy‐associated AAB. Primary probiotic assessments, including low pH and high bile salt tolerance tests, antagonistic activity test against pathogens, and antibiotic susceptibility confirmed the probiotic properties of these AAB, particularly A. cibinongensis 34L strain, which was isolated from curd. Therefore, this strain can be introduced as novel candidate probiotics that could be used in the food industry.     

Modelling the high temperature flow behaviour of sintered Cu–28Zn pre-alloyed powder compacts considering the effect of strain

In the field of the deformation process modelling, constitutive equations tend to be utilised as a calculation basis for the estimation of the materials’ flow responses. This holds also for powder metallurgy products. Hence, in this study, the flow behaviour of sintered Cu–28Zn pre-alloyed powder compacts was investigated by a collection of isothermal hot compression tests in the temperature range of 550–850°C at strain rates of 0.001, 0.01, 0.1 and 0.5?s^?1 up to the true strain of 0.6. For the sintered part with a predefined porosity of 9.4%, the impacts of the temperature and strain rate on the deformation behaviour were shown by the Zener–Hollomon parameter in an exponent-type equation. As a result, a model was developed to predict the high temperature flow behaviour of the Cu–28Zn pre-alloyed powder compact. The results indicated that the strain-dependent constitutive equations are in good conformity with the experimental results.