Petrological considerations for the demineralization of Rajmahal coals with <Emphasis Type="Italic">Pseudomonas mendocina</Emphasis> B6-1

The present study entails the results of the petrological coniderations for demineralization of Rajmahal Gondwana coals with Psudomonas mendocina B6-1. Inertinite group macerals are the dominant constituents of these coals, followed by vitrinite group, while liptinite occurs in low concentration. The amount of Mineral matter is moderately high. The concentration of major, minor and trace elements is high when compared with Clarke values. After the treatment of these coals with Pseudomonas mendocina strain B6-1, a significant reduction in the elemental content of oxygen, hydrogen and sulphur was observed. A gradual reduction of pyrite phase due to bioleaching was identified and its signatures were reflected in the XRD spectra and FTIR absorption bands. Over 5 % reduction in the ash content and decrease of major, minor and trace element to variable degrees were also noticed. Fe, As, and Ca positively correlate with the ash removal percentage indicating that the samples with high concentration of these elements were prone to demineralization with Pseudomonas mendocina strain B6-1 whereas Ni, Zn, Cr and Cu, negatively correlate with the ash removal percentage and shows that their enrichment impeded the process of demineralization. With increasing concentration of vitrinite the removal of major/minor/trace elements also increased which is attributed to the possible association of these elements with the mineral matter occurring as superficial mounting and superficial blanketing over the vitrinite macerals. This could facilitate the bacterial access to the elements to act upon and remove it to the variable extent. Some minerals occur intergrown with inertinites causing restricted bacterial action owing to the nonexposure of the mineral particles and less surface area available to the bacteria for bioleaching. Sulfur removal strongly relates with increase in inertinite content and decrease in liptinite content. This appears that sulfur associated with liptinites have shown difficult removal condition. The maximum removal of the trace elements like Cd, Cu, Co, Zn and Pb was observed from the ‘banded dull coal’ samples of the Rajmahal basin while maximum removal of major/minor elements like Fe, Ca and Mg was noticed from the ‘banded bright coal’ samples. However, maximum removal of Mn and As was also observed in the samples of ‘banded coal’.     

Effect of paper mill effluents on accumulation of heavy metals in coconut trees near Nanjangud,mysore district,Karnataka, India

Physicochemical characteristics of wastewater from one of the paper mills near Nanjangud and the differential accumulation of heavy metals in parts of coconut trees growing in the area irrigated directly by the wastewaters of a paper mill were investigated. The total dissolved and suspended solids of wastewater were 1,136.9 mg/l and 2,185.4 mg/l, respectively. Biological oxygen demand (BOD) expands and COD is beyond the tolerance limit proposed by Indian standards. The concentrations of heavy metals like Cu, Pb, Zn, Ni, Co, and Cd in coconut water, root, and leaf are higher than the limits suggested by World Health Organization. Survival of coconut trees irrigated by polluted waters indicates tolerance to toxic heavy metals. Since coconut forms part of human food chain, accumulation of toxic heavy metals may lead to organic disorders.     

A synoptic-climatic study of the onset of southwest monsoon over Mumbai

Surface and upper air synoptic features prevailing at the time of onset of southwest monsoon over Mumbai have been examined for a period of 50 years from 1947 to 1996. These synoptic situations have been found to fall under three broad categories. The study shows that on about 66% of the occasions, the onset of monsoon over Mumbai is caused by low pressure area forming over southeast and east central Arabian Sea as they move northwards, while on 28% of the occasions, the onset is due to the low pressure systems forming over northwest/head Bay of Bengal and their movement towards northwest/west northwest. Based on the findings of the study and the climatological aspects, a criterion for declaring onset over Mumbai has been suggested.     

Geochemical and statistical approach to evaluate background concentrations of Cd,Cu, Pb and Zn (case study: Eastern Poland)

An attempt was made to evaluate background concentrations of Cd, Cu, Pb and Zn by means of geochemical and statistical approach. As many as 753 samples taken from 51 profiles located in Eastern Poland were analysed. For the estimation of geochemical background values, direct geochemical methods and a statistical analysis for the whole population of samples were applied. Average values of heavy metal concentration in loess sediments (bedrock) as well as in profiles not affected by human activity were measured. The iterative 2σ technique and calculated distribution function were chosen as statistical methods. The resulting values (background concentrations range) were as follows: Cd 0.5–0.9 mg kg⁻¹, Cu 5–16 mg kg⁻¹, Pb 12–26 mg kg⁻¹ and Zn 31–47 mg kg⁻¹. All the methods applied gave similar results. The highest deviation of the background was noted for Cu and the lowest for Zn. The lowest values of background were obtained for loess sediments and the highest in the case of the multiple 2σ method.     

Misperceptions of climate-change risk as barriers to climate-change adaptation: a case study from the Rewa Delta, Fiji

While increasing research is focusing on the effective adaptation to climate change in richer (developed) countries, comparatively little has focused specifically on this subject in poorer (developing) countries such as most in the Pacific Islands region. A significant barrier to the development of effective and sustainable adaptive strategies for climate change in such places is the gap between risk and perceived risk. This study looks at a vulnerable location in Fiji—the densely populated Rewa River Delta where environmental changes resulting from shoreline retreat and floods are expected to increase over the next few decades and entail profound societal disruption. The numbers of people living in the Rewa Delta who know of climate change and could correctly identify its contributory causes are few although many rank its current manifestations (floods, riverbank erosion, groundwater salinization) as among their most serious environmental challenges. While lack of awareness is a barrier to adaptation, there are also cultural impediments to this such as short-term planning perspectives, spiritual beliefs, traditional governance structures. One way forward is to empower community leaders in places like the Rewa Delta to make appropriate decisions and for regional governments to continue working together to find solutions that acknowledge the variation in sub-regional trans-national vulnerability to climate change.     

Geochemical implications of minerals and environmentally sensitive elements of Giral lignite,Barmer Basin,Rajasthan (India)

The Barmer Basin of Rajasthan is significant for its Paleogene lignite sequences. The lignite seam occurs in Akli Formation of Barmer Basin at the depth of 06–241 m. A total of 57 lignite samples were collected from the working faces of lignite mine and were subjected to proximate analysis (moisture, ash yield, volatile matter, and fixed carbon), ultimate analysis (carbon, hydrogen, nitrogen, oxygen and sulfur), elemental analysis (Fe, Ca, Mg, Cd, Mn, K, Na, Cu, Co, Ni, Cr, Zn, and Pb) and rock-eval pyrolysis for mineral carbon (MINC). Some elements like Cu, Cd, Co, Ni, Zn, Pb, Na, and K occur in high concentration, while Mg and Ca have their concentrations lower than World Clarke average. In addition, various minerals and functional groups present in the lignite samples were analyzed through X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. The mineral (weight and atomic) percentage has also been analyzed through scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS).     

2020年云南巧家5.0级地震烈度评定及房屋震害特征

2020年5月18日巧家县发生5.0级地震,结合震区背景信息和现场调查,详细阐述此次地震烈度分布和房屋震害特征,并计算各类结构房屋的震害指数和破坏比。调查发现,本次地震的最高烈度为Ⅵ度,长轴呈NW向,与灾区地震地质构造背景、仪器烈度分布具有较好的一致性。对比分析本次地震与昭通地区、云南其他地区近年来大小相近的历史地震Ⅵ度区震害指数,结果表明,本次地震房屋震害指数相较于昭通其他地区明显偏低,但比云南其他地区偏高。分析认为,近年来巧家县各项房屋改造工程切实提高了当地房屋抗震水平,但仍需加强房屋改造建设,尤其是加快推进老旧房屋拆除及新房建设工作,进一步提升房屋抗震能力。     

横墙对框架结构动力响应的影响分析

填充墙具有显著的刚度和承载力贡献。建筑结构震害调查发现,不开洞横墙的破坏程度远小于开洞纵墙的破坏程度,从宏观现象可判断大部分多层建筑的破坏主要由结构纵向运动造成。为研究横墙在地震作用下的性能及其对结构整体动力响应的影响,以经受2021年5月21日云南漾濞6.4级地震震害的花椒园小学教学楼为研究对象,按当地抗震计算参数进行弹塑性时程分析。采用等效斜压杆模拟横向填充墙,设置无填充墙框架结构、带黏土砖墙的框架结构、带空心砖墙的框架结构和带加气混凝土砌块填充墙的框架结构模型,选取10组地震波横向输入。研究结果表明,4种结构自振周期均处于具有统计学意义的平台段,平均加速度响应较接近,质量和刚度变化不会使结构加速度产生规律的变化;受结构自重影响,无填充墙的框架结构底部剪力小于带填充墙的框架结构,带填充墙的框架结构位移远小于无填充墙的框架结构;带有多道不开洞横墙的多层框架结构的破坏主要是由结构纵向破坏引起的。