Effect of fluid concentration in titanium machining with an atomization-based cutting fluid (ACF) spray system

The aim of this work is to investigate the effect of metal-working fluid (MWF) concentration on the machining responses including tool life and wear, cutting force, friction coefficient, chip morphology, and surface roughness during the machining of titanium with the use of the ACF spray system. Five different concentrations from 5 to 15% of a water-soluble metalworking fluid (MWF) were applied during turning of a titanium alloy, Ti–6Al–4V. The thermo-physical properties such as viscosity, surface tension and thermal conductivity of these concentrations were also measured. The test results demonstrate that the tool life first extends with the increase in MWF concentration and then drops with further increase. At low concentration (e.g., 5%), a lack of the lubrication effect causes to increase in a higher friction at the tool–chip interface resulting in severe chipping and tool nose/flank wear within a short machining time. On the other hand, at high concentration, the cooling effect is less. This increases cutting temperature and a faster thermal softening/chipping/notching of the tool material and higher friction at the tool–chip–workpiece interaction zones resulting in early tool failure. A good balance between the cooling and the lubrication effects seems to be found at the 10% MWF concentration as it offers the best machining performance. However, machining with flood coolant is observed to perform the best in the range of 5–7%.     

Traditional knowledge and biodiversity conservation: a case study from Byans Valley in Kailash Sacred Landscape,India

Ethnobotanical knowledge plays a significant role in plant diversity conservation and the curing of various ailments in remote rural areas of the Indian Himalayan Region (IHR). A total of 53 plant species from 27 families have been documented from the Byans valley and are used traditionally for the treatment of various diseases. Valley inhabitants have maintained a symbiotic relationship between natural resources and their cultural belief system by developing sacred forests/groves which conserve the region's plant diversity pool. Information on sacred natural sites and traditional beliefs was documented in order to understand the environmental and conservationist implications of these rules and practices. The study provides comprehensive information about eroding traditional knowledge and biodiversity conservation practices. This study could be a pilot to strengthen the conservation practices and sustainable utilization of frequently used bioresources by understanding the traditional knowledge system and conservation ethics of tribal communities in the Himalayan region.     

Structural and molecular alterations in arsenic-induced hepatic oxidative stress in rats: a FTIR study

Arsenic (As) is an ubiquitously distributed environmental toxicant predominantly contaminating drinking water. A number of studies indicated that oral exposure of humans to inorganic As produced damage to various body tissues including liver. Oxidative stress is thought to play a major role in As-induced hepatotoxicity. In this study, Fourier transforms infrared (FTIR) spectroscopy approach was applied to determine whether chronic As exposure at 25 ppm, intragastrically for 12 weeks, affected oxidative stress status in rat liver. Data demonstrated that chronic As administration exacerbated oxidative stress as was evidenced by suppressed antioxidant defense system and increased lipid peroxidation and protein oxidation. The FTIR study showed that peak area value of amide A decreased significantly followed by reduced amide I and amide II peak area in an As-treated rat liver suggesting altered protein profile. The change of Olefinic?CH stretching band and C?O stretching of triglycerides band indicated the altered lipid levels due to metallic exposure. The fall in the peak area of PO₂^? asymmetric stretching in the As-treated group might be due to compositional changes of nucleic acids. Hence, the results of this study indicate that As-induced oxidative stress was associated with structural and molecular modifications in proteins, lipids, and glycogen in a rat liver that may help to elucidate molecular mechanisms underlying metal-mediated hepatic damage.     

Microplastics pollution in Bangladesh: current scenario and future research perspective

ABSTRACT

Microplastics are emerging environmental pollutants that have gained tremendous scientific interest in recent years. These micropollutants are omnipresent both in the terrestrial and aquatic environments posing a deleterious threat to the ecosystem and biodiversity. So, it is important to develop a deep understanding of the environmental fate and potential adverse impacts of microplastics on the aquatic and terrestrial environments. By critically reviewing the previously published scientific literature, the present synthesis briefly outlines the characteristics, occurrence and potential toxic effects of microplastics on terrestrial and aquatic biota. The article also focuses on some innovative approaches for sustainable remediation of macroplastics as well as microplastics. Since the concept of microplastics pollution has yet in its infancy in Bangladesh, this synthesis provides an overview of the current scenario of microplastics pollution and some future research recommendations in the context of Bangladesh which might be helpful to the novice researchers of this field.     

Multivariate statistical techniques for the evaluation of spatial and temporal variations in water quality of the Mahanadi river–estuarine system (India) – a case study

Spatial and temporal distributions of water quality using multivariate statistical techniques for the evaluation of nutrients (NO₂-N, NO₃-N, NH₄-N, PO₄-P, SiO₄-Si, total N, total P) in relation to some physico-chemical features (DO, BOD, TSS, TDS, SO₄²⁻, Cl⁻) were studied for 31 different stations of the Mahanadi river–estuarine system in the eastern part of India. The seasonal nutrient variations (except SiO₄-Si) exhibit higher values during monsoon season in unpolluted stations and the reverse trends for polluted stations, which are related to agricultural run-off and regional anthropogenic activities respectively. Silicate shows a well defined pattern of distribution with a higher concentration during the monsoon, which is slightly removed from the estuarine water of Mahanadi during the pre-monsoon season. The results of R-mode factor analyses revealed that anthropogenic contributions are responsible for the increase in nutrients and the decrease in DO and pH levels of the water. The magnitude of BOD with respect to total N and P demonstrates the intensity of organic pollution in the system. The removal of silicate in the saline system is clearly visible through factor analysis and the different mode of association of TSS is reflected seasonally. The relationships among the stations are highlighted by cluster analysis, represented in dendograms to categorize different levels of contamination.     

Coal fly ash utilization: low temperature sintering of wall tiles

We present here a study of the sintering of fly ash and its mixture with low alkali pyrophyllite in the presence of sodium hexa meta phosphate (SHMP), a complex activator of sintering, for the purpose of wall tile manufacturing. The sintering of fly ash with SHMP in the temperature range 925-1050 degrees C produces tiles with low impact strength; however, the incremental addition of low alkali pyrophyllite improves impact strength. The impact strength of composites with 40% (w/w) pyrophyllite in the fly ash-pyrophyllite mix satisfies the acceptable limit (19.6J/m) set by the Indian Standards Institute for wall tiles. Increasing the pyrophyllite content results in an increase in the apparent density of tiles, while shrinkage and water absorption decrease. The strength of fly ash tiles is attributed to the formation of a silicophosphate phase; in pyrophyllite rich tiles, it is attributed to the formation of a tridymite-structured T-AlPO(4) phase. Scanning electron micrographs show that the reinforcing rod shaped T-AlPO(4) crystals become more prominent as the pyrophyllite content increases in the sintered tiles.     

Assessment of mining activities on tree species and diversity in hilltop mining areas using Hyperion and Landsat data

Environmental Science and Pollution Research - The tree species and its diversity are two critical components to be monitored for sustainable management of forest as well as biodiversity...     

Cold plasma technology: advanced and sustainable approach for wastewater treatment

Environmental Science and Pollution Research - Cold plasma has been a potent energy-efficient and eco-friendly advanced oxidation technology which has gained attention in recent decades as a...