Agricultural and agro-industrial residues-to-energy: Techno-economic and environmental assessment in Brazil

This study aims to quantify the environmentally sustainable and economically feasible potentials of agricultural and agro-industrial residues to generate electricity via direct combustion in centralised power plants in Brazil. Further, the energy savings and greenhouse gas (GHG) reduction potential of replacing natural gas-based electricity by bioenergy have been assessed. To this end, a methodology has been developed based on an integrated evaluation, incorporating statistical and geographical information system (GIS)-based analysis, and a life-cycle-assessment approach. Results reveal that the environmentally sustainable generation potential is nearly 141 TWh/year, mainly concentrated in the South, Southeast, and Midwest regions of the country. Sugarcane, soybean and maize crop residues are the major feedstocks for available bioenergy. On the other hand, the economic potential is far lower, accounting to 39 TWh/year. The total GHG mitigation is nearly 18 million tonne CO₂e and could reach 64 million tonne CO₂e yearly, if the technical potential is considered. The gap between technical and economic potentials implies that constraints to bioenergy are not related to a lack of resources, but rather associated to economic, logistical, regulatory and political barriers.     

Pipeline hydraulic transport of biomass materials: A review of experimental programs,empirical correlations,and economic assessments

Pipeline hydro-transport, an economically viable means of delivering large volumes of biomass, can replace conventional modes of transport – road, rail, and river - to improve the economy of pulp and paper mills, as well as bio-based energy facilities. This paper is a review of experimental and theoretical studies conducted by various sectors on the transport of wood and non-wood biomass-water mixtures (slurries) in pipes. The aims were to collect technical challenges, governing mechanical equations, and associated economic issues, as well as to identify the gaps in knowledge in the area. There have been several experiments conducted on pipeline hydro-transport of wood chips over a wide range of pipeline materials, lengths, and diameters. However, pipeline transport of non-wood agricultural residue slurries, as well as the performance of the centrifugal slurry pump handling such mixtures, has recently been investigated in a single lab-scale pipeline facility. Several researchers have proposed empirical correlations to estimate friction loss in wood chip slurries flowing in pipes and also recommended technically and economically optimum pumping velocities. Those correlations, however, are reported to come with noticeable deviations from one another and from experimental measurements. One empirical correlation has been also proposed to predict, with an uncertainty of less than 10%, the longitudinal pressure gradients in pipeline hydro-transport of agricultural residue biomass. All the experimental measurements and empirical correlations based some studies on the economic feasibility of pipelining wood chip-water mixtures. These studies proved the concept of economy of scale to be highly applicable to biomass pipeline systems.     

Determination of physical and chemical properties of waste tyres in usage/storage areas

Used tyres interact with soil, water and the atmosphere during temporary or permanent storage and also when used as additive or paving materials in landscapes, asphalt, concrete and for coastal protection. Various organic and inorganic compounds can penetrate into the environment from used tyres at various rates dependent on climatic and soil conditions. In this study, laboratory leaching batch experiments were conducted to determine the heavy metals and other constituents that could possibly penetrate into the leachate created during tyre usage/storage. The results obtained in this study showed that tyres were dissolved due to their usage and the climatic and environmental conditions thus leading to soil and groundwater pollution in their usage/reuse/storage/disposal areas. Zinc concentrations were the highest among the heavy metals measured in the simulated leachate. The average weight loss for all tyre samples was calculated as 3.6‰.     

Influence of pyrolysis temperature and residence time on available nutrients for biochars derived from various biomass

To study the effect of pyrolysis temperature and residence time on properties and nutrient values, biochars were produced from corn stalk, rice hull, peanut hull and tobacco stalk at 200°C–700°C for one minute and 60 minutes, respectively. When temperatures and residence times increase, yields of biochars decrease accompany with higher pH values of biochars, changing the acidity of biochars from acidic to alkaline, and increasing total C and parts of the available N and K contents of biochars. These results indicate that feedstock and preparation technology are important factors affecting available nutrients of biochars.     

Bangladesh’s diverse and complex physical geography: implications for agricultural development

Bangladesh’s physical geography is much more diverse and complex than is generally recognised. The landscapes of piedmont, river, tidal and estuarine floodplains, uplifted blocks and hill areas are described together with the associated environmental hazards that currently constrain crop production in specific regions. Practical measures to increase crop production in parallel with the projected increase in the country’s population in the next 20–30 years are reviewed, including measures to increase the efficiency of fertiliser use and irrigation, and structural measures to reduce the hazards of salinity incursion, sea-level rise and seasonal flooding.     

Novel Crystalline SiO<Subscript>2</Subscript> Nanoparticles via Annelids Bioprocessing of Agro-Industrial Wastes

The synthesis of nanoparticles silica oxide from rice husk, sugar cane bagasse and coffee husk, by employing vermicompost with annelids (Eisenia foetida) is reported. The product (humus) is calcinated and extracted to recover the crystalline nanoparticles. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and dynamic light scattering (DLS) show that the biotransformation allows creating specific crystalline phases, since equivalent particles synthesized without biotransformation are bigger and with different crystalline structure.     

气象传感器在农业中的应用

人工气候环境测控系统可选用现成气象仪器，文章重点阐述气象传感器的选型及其信号转换电路。     

Macroeconomic impacts of bioenergy production on surplus agricultural land—A case study of Argentina

This paper assesses the macroeconomic impacts in terms of GDP, trade balance and employment of large-scale bioenergy production on surplus agricultural land. An input–output model is developed with which the direct, indirect and induced macroeconomic impacts of bioenergy production and agricultural intensification, which is needed to make agricultural land become available for bioenergy production, are assessed following a scenario approach. The methodology is applied to a case study of Argentina. The results of this study reveal that large-scale pellet production in 2015 would directly increase GDP by 4%, imports by 10% and employment by 6% over the reference situation in 2001. When accounting for indirect and induced impacts, GDP increases by 18%, imports by 20% and employment by 26% compared to 2001. Agricultural intensification reduces but does not negate these positive impacts of bioenergy production. Accounting for agricultural intensification, the increase in GDP as a result of bioenergy production on surplus agricultural land would amount to 16%, 20% in imports and 16% in employment compared to 2001.     

试论三江平原生态建设

三江平原经过50多年的开发,不但没有形成一个好的湿地农业生态体系,而且使原湿地生态系统也遭到严重破坏.三江平原湿地生态建设中既要保护重建湿地生态,又要建设湿地农业生态,发展经济,应消化吸收古今中外湿地生态建设的经验与技术,探索三江平原生态建设的策略与措施,实现三江平原生态经济可持续发展.     

Is the Feminist Ethics of Care framework a useful lens for GM crop risk appraisal in the global south?

The risk assessment of genetically modified (GM) crops is assumed to be a benign regulatory tool due to its perceived objectivity and freedom from the morals and values that pervade society. Yet, against the current backdrop of ecological, social and political volatility, issues that cannot be resolved using the existing framework in South Africa are consistently emerging. This paper calls for a reformation of regulatory procedures by exploring the potential of Feminist Care Ethics to illuminate an alternative approach to the assessment of GM crops. While fresh thinking is welcome into the entangled field of biotechnology governance, there remains little understanding of how to accommodate such approaches in the context of the Global South. Twenty three interviews with participants from governmental, non-governmental and academic bodies were carried out in order to explore the potential of a Feminist Ethic of Care as an alternative framework. By examining the current appraisal procedures and tracing their evolution, problems with the current system were illuminated. To assess the suitability of the care ethic framework and ensure reflexivity, a hybrid approach to thematic analysis was applied. Using themes derived from feminist literature such as relationships, context, power, narrative and emotion, new ‘ways of seeing’ risk emerged and illuminated salient issues that are habitually ignored by the current science-based risk approach to assessment. The current approach was found to be flawed, stemming from a neoliberal, productivist perception of our socio-ecological environment. Feminist perspectives instead ask us to broaden the framing of risk, to consider different knowledges, to re-imagine ourselves as social, rather than economic beings, to tap into the capacity of socio-ecological relations and to recognize and dismantle power structures. The research concludes that although the care ethics themes offer a new approach to GM crop regulation, meaningful change will not arise from simply adding these elements to the current system. Rather, a call must be made for a re-imagining, and redesigning, both institutionally and politically-economically.