Metal- and ionic liquid-based photocatalysts for biodiesel production: a review

Environmental Chemistry Letters - Diminishing petroleum reserves, increasing carbon emissions, and the growing demand for fuels are calling for alternative fuels. Global diesel consumption...     

An IoT-based waste management system monitored by cloud

Clever solid waste bin is important to create a well-organized and dynamic waste management system. This paper presents the novel way of carrying out an integrated sensing system which automates the solid waste management process. The proposed smart waste bin is based on ultrasonic-level sensor and various gas sensors which automatically sense the hazardous gases and the maximum limit of waste. The approach is unique and uses cloud and mobile app-based monitoring. Two important features of work are it not only checks the maximum waste level of the bin but also checks various stinky gases. The other part of the work is conveying the information to the responsible authority. This unique approach takes the assistance of cloud sever because of its advantages in field of usability, accessibility and disaster recovery. The information can be linked with municipality web server for immediate action. The waste bins are tracked by a unique number which represents its location. The eccentric technique gives all information related to physical condition of a particular bin and can easily reach the corresponding authority. The whole information is interconnected with a cloud-based web-information system at the host server.     

Studies on process optimization of biodiesel production from waste cooking and palm oil

This work investigated the optimisation of biodiesel production from waste cooking oil (WCO) and palm oil using a two-step transesterification process for WCO and base catalysed transesterification for palm oil. Transesterification reactions were carried out to investigate the effects of prepared catalyst CaO, methanol/WCO and methanol/palm oil ratio and temperature on the yield of biodiesel. A series of experiments were conducted to determine the best conditions for biodiesel production, using methanol/oil ratio between 4:1 and 11:1 and contact time varying between 2 and 4 h. Biodiesel yield of around 90 and 70% was obtained for palm and waste cooking oil at the methanol/oil ratios of 6:1 and 8:1 at temperature of 60 °C for reaction time of 4 h using prepared CaO as catalyst. The physicochemical properties of palm and WCO biodiesel were carried out using standard methods, while the fatty acid profile was determined using gas chromatography. The investigation concludes that biodiesel obtained from palm and waste cooking oil was within the specified limit.     

Advances and perspective in bioremediation of polychlorinated biphenyl-contaminated soils

In recent years, microbial degradation and bioremediation approaches of polychlorinated biphenyls (PCBs) have been studied extensively considering their toxicity, carcinogenicity and persistency potential in the environment. In this direction, different catabolic enzymes have been identified and reported for biodegradation of different PCB congeners along with optimization of biological processes. A genome analysis of PCB-degrading bacteria has led in an improved understanding of their metabolic potential and adaptation to stressful conditions. However, many stones in this area are left unturned. For example, the role and diversity of uncultivable microbes in PCB degradation are still not fully understood. Improved knowledge and understanding on this front will open up new avenues for improved bioremediation technologies which will bring economic, environmental and societal benefits. This article highlights on recent advances in bioremediation of PCBs in soil. It is demonstrated that bioremediation is the most effective and innovative technology which includes biostimulation, bioaugmentation, phytoremediation and rhizoremediation and acts as a model solution for pollution abatement. More recently, transgenic plants and genetically modified microorganisms have proved to be revolutionary in the bioremediation of PCBs. Additionally, other important aspects such as pretreatment using chemical/physical agents for enhanced biodegradation are also addressed. Efforts have been made to identify challenges, research gaps and necessary approaches which in future, can be harnessed for successful use of bioremediation under field conditions. Emphases have been given on the quality/efficiency of bioremediation technology and its related cost which determines its ultimate acceptability.     

Dental fluorosis—a case study from Nawa tehsil in Nagaur district,Rajasthan (India)

A study was carried out in Nawa tehsil of Nagaur district to assess the prevalence of dental fluorosis and its crippling effect due to ingestion and prolonged exposure of fluoride over a long period of time. During the survey of the study area, high concentration of fluoride (14.62 ppm) has been recorded. The presence of fluoride in quantities in excess of limits is a serious matter of concern from a public health point of view. Due to higher fluoride level in groundwater, several cases of dental fluorosis have appeared at alarming rate in the study area. The children’s teeth are damaged and are characterized by black and brown stains as well as cracking and pitting of the teeth have been observed. In the study area, 93.12% population suffered from dental fluorosis, and it was more prevalent in men (94.90%) than in women (90.00%). Dental fluorosis was also examined according to different grades. Out of the total 72 afflicted, in the 4–16-year age group, 41.46% were suffering from Grade I, Grade II was more prevalent in 33.85% of the 17–28-year age group and similarly Grade II was more prevalent in 39.13% of the 29–40-year age group. In the age group of above 40 years, grade III and grade IV were more prevalent. Thus, in the higher age group, the prevalence and severity of fluorosis is almost certainly due to longer exposure to fluoride. The major risk factor consistently identified for dental fluorosis was the consumption of fluoridated drinks and fluoride supplements. Ingestion of calcium, vitamin D and vitamin C is effective in protection from fluoride toxicity to certain extent.     

Urinary fluoride as a monitoring tool for assessing successful intervention in the provision of safe drinking water supply in five fluoride-affected villages in Dhar district, Madhya Pradesh, India

Endemic fluorosis was detected in 31 villages in the Dhar district of Madhya Pradesh, Central India. Out of the 109 drinking water sources that were analyzed, about 67 % were found to contain high concentration of fluoride above the permissible level of 1.0 mg/l. Dental fluorosis among the primary school children in the age between 8 and 15 served as primary indicator for fluoride intoxication among the children. Urinary fluoride levels among the adults were found to be correlated with drinking water fluoride in 10 villages affected by fluoride. Intervention in the form of alternate safe water supply in five villages showed significant reduction in the urinary fluoride concentration when compared to the control village. Urinary fluoride serves as an excellent marker for assessing the effectiveness of intervention program in the fluoride-affected villages.     

Improving land use inference by factorizing mobile phone call activity matrix

Land use is shaped by human activities. Traditional methods of measuring land uses (e.g. surveys and remote sensing techniques) often have difficulties in capturing human activities. The near-ubiquitous coverage of mobile phones opens up a new way to investigate land use through human activities. We propose to analyze land use by characterizing human activity patterns based on the aggregated call volume, and apply non-negative matrix factorization to identify fundamental behavioral classes. Using tower-based call data from Dakar, Senegal, we discover two fundamental land use patterns: commercial/business/industrial (C/B/I) and residential. Then, the land use of the reception area of each cell tower can be inferred based on the weights obtained for each basis vector. To evaluate the proposed approach, the results are compared with two points-of-interest (POI) data sets obtained from OpenStreetMap and Facebook’s Graph API. We have found that a majority of POIs like embassies, offices, and hotels are located in the predicted C/B/I areas; specifically, there is a strong positive correlation between estimated land use weights and the number of related POIs. Furthermore, we have shown analyzing 24-h call pattern matrix can track daily land use changes.