Water quality assessment of a tropical coastal lake system using multivariate cluster,principal component and factor analysis

Statistical techniques represent a reliable tool for classifying, modelling and interpreting surface water quality monitoring data, particularly for lakes. The complexity associated with the analysis of a large number of measured variables, however, is a major problem in water quality assessments. Multivariate analysis, such as cluster analysis and factor analysis (FA), was utilized in this study for the analysis of water quality data (including water discharges and 28 water quality parameters) for Akkulam–Veli Lake, a tropical coastal lake system in Kerala, India. This lake is partially divided into two sub‐systems, namely Veli Lake and Akkulam Lake. Akkulam Lake exhibits freshwater characteristics, in contrast to Veli Lake, which exhibits saline water characteristics because of its close proximity to the sea. Thus, studying this lake provides insights into water quality variations in both a freshwater and saline water lake in a tropical region. Water quality patterns and variations in Akkulam–Vela Lake over three seasons, including pre‐monsoon (PRM), monsoon (MON) and post‐monsoon (POM), also were studied, utilizing multivariate techniques. The organic pollution factor played a significant role on lake water quality during PRM. The influence of organic pollution tends to decrease during MON and POM, a particular situation faced by urban lakes in tropical regions. Polluted stretches in a lake system during different seasons can easily be ascertained by hierarchical cluster analysis. Further, the factors affecting a lake system as a whole, as well as for a particular sampling site, can easily be identified by FA. Improved water quality can be observed during POM. Akkulam and Vela lakes exhibit a wide variation in water quality during all seasons, a finding that corroborates a water flow obstruction from Akkulam Lake to Veli Lake because of the bund existing between the two lakes. The location of the bund is identified as the major reason for different hydrochemical processes in A–V Lake.     

KEEPING QUALITY OF DIFFERENT PACKAGED SALTED ATLANTIC BONITO "LAKERDA"

Quality and shelf life of salted Atlantic bonito (lakerda) packaged in brine, under vacuum and in oil conditions and stored at 4  ±  1C were studied. The sensory scores of lakerda stored in all package types at 4C were 14 weeks, respectively. The microbiological count of the vacuum-packaged lakerda was extended than that lower of other group sample. Overall results of this study showed that 9 weeks of storage of lakerda in brine was the beginning of spoilage, whereas storage of samples in oil and vacuum package delayed onset of spoilage about 2–3 weeks in terms of chemical analysis. Lakerda stored in cold storage as sensory, chemical and microbiological results for brine- and oil-packaged lakerda showed us that week 11 was the beginning of spoilage, and for vacuum-packaged lakerda, week 13 was the beginning of spoilage.

PRACTICAL APPLICATIONS

Raw fish and processed fish product is highly perishable and has a short shelf life. Packing processing is finding increasing use in the food industry because of its relative advantages versus other food processing methods in eliciting minimal changes in the flavor, microbiological and nutritional qualities of the final product. This paper illustrates the changes induced in salted fish by packaging at different types. By using oil- and vacuum-packaged treatment, shelf life of traditional-packaged (in brine) lakerda could be extended at 4C from 9 weeks to 11–13 weeks.     

Effect of milling energy on mechanical activation of (Mo + Si3N4) powders during the synthesis of Si3N4–MoSi2 in situ composites

Attempts have been made to study the effect of milling energy and type of grinding media on the mechanical activation during the production of MoSi₂ from a reaction between Mo and Si₃N₄. Powder mixtures of Mo and Si₃N₄ in the molar ratios of 1:1, 1:2 and 1:3 were ball milled using WC, steel, and ZrO₂ grinding media for mechanical activation. In order to evaluate the results obtained after high-energy ball milling and pyrolysis of these milled powder mixture, milling parameters have been converted to two energy parameters, namely, impact energy of the ball and total energy of milling. The optimum impact energy of ball required for mechanical activation of Mo + xSi₃N₄ (x = 3, 2, 1) powder mixtures by WC grinding media was found to be in the range of 0.145–0.173 J, which leads to a reduction of pyrolysis temperature by 100–200 °C. Samples milled with higher impact energy than the optimum range led to formation of undesirable phases, which dilutes the effect of mechanical activation. Samples milled with both steel and ZrO₂ grinding media having lower impact energies than the optimum show the presence of enormous contamination during milling and phases like ZrSi₂, Fe₃Si and Fe₅Si₃ were observed after pyrolysis without any significant reduction in pyrolysis temperature required for MoSi₂ synthesis.     

The clinical course and cardiohemodynamic status of patients with different variants of diphtheritic myocarditis

The clinical course was studied as was the condition of cardiohemodynamics in 126 patients with different variants of diphtherial myocarditis (DM) versus 23 patients with unspecific infectious and allergic myocarditis (UIAM). Early DM in the majority of cases runs a moderately severe or severe course because of a stronger--by comparison with late DM and UIAM--predisposition to cardiac insufficiency, sinus bradycardia and heart blocks as well as of a moderately severe systolic dysfunction of the left ventricle (LV), as evidenced by Echo-CG. Late DM runs, on the whole, a mild course, and is associated with minimal LV systolic function inadequacies.     

A comparative study on the processing, dielectric and electrical properties of PMN based solid solutions

Lead magnesium niobate (PMN) based binary with lead titanate (PT), lead iron niobate (PFN) and lead zinc niobate (PZN) and ternary with PZN-PT and PFN-PT solid solutions have been synthesized. In depth characterization using X-ray diffraction and SEM techniques have revealed the major perovskite phase formation. Amongst all the solid solutions, PMN-PZN-PT has given the highest values of permittivity as 19,740 and 23,700 withT _c as 34°C when sintered at 1080°C and 1180°C respectively on the one hand and on the other, PFN containing solid solutions exhibited distinct deviation from the relaxor behaviour.     

Fig tree sap: antithrombogenicity on nylon surfaces

An effort is made to study the anti-thrombogenic property of the latex of fig tree by immobilizing its components on nylon surface. It is also evaluated, how such surfaces may effect the blood compatibility by investigating variations in surface energy parameters, plasma recalcification time and platelet adhesion using calf’s blood.