Social representations of socioenvironmental dynamics in extractive ecosystems and conservation practices with sustainable development: a bibliometric analysis

Environment, Development and Sustainability - Social representations necessarily originate from the interaction between individuals and groups in a social setting through communication and shared...     

Numerical simulation of municipal solid waste combustion in a novel two-stage reciprocating incinerator

A mathematical model was presented in this paper for the combustion of municipal solid waste in a novel two-stage reciprocating grate furnace. Numerical simulations were performed to predict the temperature, the flow and the species distributions in the furnace, with practical operational conditions taken into account. The calculated results agree well with the test data, and the burning behavior of municipal solid waste in the novel two-stage reciprocating incinerator can be demonstrated well. The thickness of waste bed, the initial moisture content, the excessive air coefficient and the secondary air are the major factors that influence the combustion process. If the initial moisture content of waste is high, both the heat value of waste and the temperature inside incinerator are low, and less oxygen is necessary for combustion. The air supply rate and the primary air distribution along the grate should be adjusted according to the initial moisture content of the waste. A reasonable bed thickness and an adequate excessive air coefficient can keep a higher temperature, promote the burnout of combustibles, and consequently reduce the emission of dioxin pollutants. When the total air supply is constant, reducing primary air and introducing secondary air properly can enhance turbulence and mixing, prolong the residence time of flue gas, and promote the complete combustion of combustibles. This study provides an important reference for optimizing the design and operation of municipal solid wastes furnace.     

Recycling of waste glass as a partial replacement for fine aggregate in concrete

Waste glass creates serious environmental problems, mainly due to the inconsistency of waste glass streams. With increasing environmental pressure to reduce solid waste and to recycle as much as possible, the concrete industry has adopted a number of methods to achieve this goal. The properties of concretes containing waste glass as fine aggregate were investigated in this study. The strength properties and ASR expansion were analyzed in terms of waste glass content. An overall quantity of 80 kg of crushed waste glass was used as a partial replacement for sand at 10%, 15%, and 20% with 900 kg of concrete mixes. The results proved 80% pozzolanic strength activity given by waste glass after 28 days. The flexural strength and compressive strength of specimens with 20% waste glass content were 10.99% and 4.23%, respectively, higher than those of the control specimen at 28 days. The mortar bar tests demonstrated that the finely crushed waste glass helped reduce expansion by 66% as compared with the control mix.     

Ultimate analysis and heating value prediction of straw by near infrared spectroscopy

Ultimate analysis and heating value determination are two of the most important routine analyses for exploiting agricultural wastes for energy conversion. The use of near infrared spectroscopy (NIRS) was investigated as an alternative method to predict the carbon, hydrogen, and nitrogen content and the heating value of straw. A total of 222 straw samples, collected from 24 provinces of China, were used for NIRS calibration and validation in this study. The $R_{\text{v}}^2$ and standard error of predictions in independent validation were, respectively, 0.97 and 0.37% for C, 0.77 and 0.17% for H, 0.87 and 0.10% for N and 0.96 and 181 J/g for heating value. A multiple linear regression (MLR) model was also built to predict the heating value from the contents of C, H and N. The MLR equation gave good prediction (standard error of prediction = 224 J/g) when evaluated using the same validation set as the NIRS. Therefore, rapid analysis of straw can be achieved through the constructed equations, saving analytical time and cost.     

Complaints regarding occupational health and safety in the area of Thessaloniki (Greece)

This paper deals with the complaints regarding occupational health and safety in the area of Thessaloniki (Greece). It seeks to examine who are the complainers and which companies or activities do they complain about, to what extent are complaints relevant to occupational health and safety and whether the complaints result to penalties. Such complaints do not pertain to all economic sectors equally, nor do they derive from all kinds of sources. Furthermore, it appears that complaints “irrelevant” to occupational health and safety are twice as many as the “relevant” ones. In three quarters of the cases, the complaints do not result to any kind of sanction; more specifically, in one fifth of the cases, the complaints are not followed by any action taken by the office in charge. All things considered, it seems that filing complaints does not imply finding the most dangerous workplaces. Therefore, investigation of complaints should not be considered more significant than other inspection activities.     

Life-cycle assessment of flash pyrolysis of wood waste

This work analyzes a process known as flash pyrolysis, which produces bio fuels using biomass for power generation. A life-cycle assessment of flash pyrolysis of wood waste was conducted to study whether a flash pyrolysis plant set up locally would be environmentally friendly. The results obtained show that the process of flash pyrolysis of wood waste is in fact environmentally friendly, and the process has little contribution to the environment. However, efforts still have to be made to address the global warming potential issue. Continuous research and developments must be carried out to further reduce the global warming potential of the flash pyrolysis.     

Role of organic and black carbon in the chemical composition of atmospheric aerosol at European background sites

The mass concentrations of inorganic ions, water-soluble organic carbon, water-insoluble organic carbon and black carbon were determined in atmospheric aerosol collected at three European background sites: (i) the Jungfraujoch, Switzerland (high-alpine, PM_2.5 aerosol); (ii) K-puszta, Hungary (rural, PM_1.0 aerosol); (iii) Mace Head, Ireland (marine, total particulate matter). At the Jungfraujoch and K-puszta the contribution of carbonaceous compounds to the aerosol mass was higher than that of inorganic ions by 33% and 94%, respectively. At these continental sites about 60% of the organic carbon was water soluble, 55–75% of the total carbon proved to be refractory and a considerable portion of the water soluble, refractory organic matter was composed of humic-like substances. At Mace Head the mass concentration of organic matter was found to be about twice than that of nonsea-salt ions, 40% of the organic carbon was water soluble and the amount of highly refractory carbon was low. Humic-like substances were not detected but instead low molecular weight carboxylic acids were responsible for about one-fifth of the water-soluble organic mass. These results imply that the influence of carbonaceous compounds on aerosol properties (e.g. hygroscopic, optical) might be significant.     

Runoff water management technologies for dryland agriculture on the Loess

SUMMARY

Arid and semi-arid environments undergo periodic seasonal agricultural droughts of varying extents and duration, erratic and ineffective rainfall of high intensity and short duration, with high surface runoff. High efficiency water-harvesting agriculture has been routinely used in the Loess Plateau agricultural production of China over the past 10 years. Localized habitat effect and regional water resource enrichment are the theoretical basis of high efficient water-harvesting agriculture. Features of this agricultural system are described, including: water harvesting of surface runoff from roads and collection in concrete yards on plastic sheets; water storage cellar tanks for harvesting runoff to provide life-saving/critical irrigation, with devices for water lifting and conveying such as hand pumps and pipelines; feasible methods of water use for limited supplies such as drip, hole, subsoil, and super-sheet irrigation; agronomic measures of high water use efficiency; and field micro-catchment for water harvesting and conservation to increase fallow efficiency in rainy seasons. Using the stored runoff water to irrigate the mulched winter wheat and spring corn, as well as vegetables and fruit trees, significant yield increasing and water use efficiency improvements have been achieved. Plastic mulching for increasing fallow efficiency in rainy seasons and improving yield of the next winter wheat crop have been developed and demonstrated. These techniques have provided obvious benefits in terms of soil and water conservation on slope farmland in the hill regions and remarkable effects of storing water and reducing drought in the dryland farming regions have been obtained.     

Effect of Hybrid Tackifiers on Adhesion Properties of Epoxidized Natural Rubber-Based Pressure-Sensitive Adhesives

Viscosity, peel and shear strength of epoxidized natural rubber (ENR)-based pressure-sensitive adhesive was studied by using hybrid tackifiers consisting of a mixture of coumarone-indene resin and petro resin. The coumarone-indene resin concentration was fixed at 40 parts per hundred parts of rubber (phr). The concentration of petro resin, however, was varied from 20 to 80 phr. Toluene and polyethylene terephthalate (PET) film were used as the solvent and coating substrate respectively throughout the experiment. Viscosity of adhesive was determined by a HAAKE Rotary Viscometer whereas peel and shear strength was measured by a Lloyd Adhesion Tester. Results show that viscosity and shear strength decreases with increasing petro resin concentration. However, peel strength exhibits a maximum value at 40 phr petro resin, an observation which is attributed to maximum wettability and compatibility of adhesive on the substrate. ENR 25-based adhesive exhibits higher viscosity and peel strength but lower shear strength compared to the ENR 50 adhesive system.