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This paper develops a strategy for the continuing and improved supply of woodfuels to urban and industrial consumers in Sub-Sahara Africa. It argues that continued use of these fuels is not only a necessity, but is also in the best economic interest of most of the countries in this region. It shows that intensified and more orderly utilization of woodfuels can help to enhance, rather than impinge upon environmental parameters. Some examples are provided that illustrate how such strategies can be put into practice.

AbstractChina is under pressure to improve its agricultural productivity to keep up with the demands of a growing population with increasingly resource‐intensive diets. This productivity improvement must occur against a backdrop of carbon intensity reduction targets, and a highly fragmented, nutrient‐inefficient farming system. Moreover, the Chinese government increasingly recognizes the need to rationalize the management of the 800 million tonnes of agricultural crop straw that China produces each year, up to 40% of which is burned in‐field as a waste. Biochar produced from these residues and applied to land could contribute to China's agricultural productivity, resource use efficiency and carbon reduction goals. However competing uses for China's straw residues are rapidly emerging, particularly from bioenergy generation. Therefore it is important to understand the relative economic viability and carbon abatement potential of directing agricultural residues to biochar rather than bioenergy. Using cost‐benefit analysis (CBA) and life‐cycle analysis (LCA), this paper therefore compares the economic viability and carbon abatement potential of biochar production via pyrolysis, with that of bioenergy production via briquetting and gasification. Straw reincorporation and in‐field straw burning are used as baseline scenarios. We find that briquetting straw for heat energy is the most cost‐effective carbon abatement technology, requiring a subsidy of $7 MgCO2e−1 abated. However China's current bioelectricity subsidy scheme makes gasification (NPV $12.6 million) more financially attractive for investors than both briquetting (NPV $7.34 million), and pyrolysis ($−1.84 million). The direct carbon abatement potential of pyrolysis (1.06 MgCO2e per odt straw) is also lower than that of briquetting (1.35 MgCO2e per odt straw) and gasification (1.16 MgCO2e per odt straw). However indirect carbon abatement processes arising from biochar application could significantly improve the carbon abatement potential of the pyrolysis scenario. Likewise, increasing the agronomic value of biochar is essential for the pyrolysis scenario to compete as an economically viable, cost‐effective mitigation technology.

The basins of the Indus and Ganges rivers cover 2.20 million km2 and are inhabited by more than a billion people. The region is under extreme pressures of population and poverty, unregulated utilization of the resources and low levels of productivity. The needs are: (1) development policies that are regionally differentiated to ensure resource sustainability and high productivity; (2) immediate development and implementation of policies for sound groundwater management and energy use; (3) improvement of the fragile food security and to broaden its base; and (4) policy changes to address land fragmentation and improved infrastructure. Meeting these needs will help to improve productivity, reduce rural poverty and improve overall human development.

Abstract Sweet sorghum, a C4 plant, is known to be a unique, versatile, and potential energy crop that can be separated into starchy grains, soluble sugar juice, and lignocellulosic biomass. The fermentable sugars in the juice (53–85% sucrose, 9–33% glucose, and 6–21% fructose) can be directly fermented into ethanol. The grain is primarily starch (62–75%), which can be hydrolyzed and fermented into ethanol. The bagasse, a fibrous lignocellulosic material, can be used to produce cellulosic ethanol, heat and/or power co-generation. In this review, the potential of sweet sorghum for bioenergy production (of various forms) using recently developed cultivars with improved agronomic performance was discussed. In addition, sweet sorghum was compared with other starch, sugar, and lignocellulosic feedstocks. Studies have been conducted on alternative pathways to convert whole sweet sorghum stalks and bagasse into bioenergy. However, very little review of the techno-economic analysis of bioenergy production and co-products from sweet sorghum has been published. The aim of this research was to review the current knowledge of agronomic requirement for cultivating sweet sorghum, the productivity of recently developed cultivars for bioenergy production, and pathways of converting sweet sorghum crop into bioenergy as well as the techno-economic feasibility of using sweet sorghum for bioenergy.

Abstract A hydrocarbon miscible flood was initiated in the Wizard Lake D-3A pool in late 1969. The scheme involved placing a slug of LPG at the gas-oil interface, and displacing it vertically downward with dry gas while injecting water to stabilize the oil-water contact. Ultimate recovery is expected to be 323 million stock tank barrels, 84per cent of the original oil-in-place and 69 million stock tank barrels higher than under primary depletion. The Wizard Lake D-3A pool, located in central Alberta, is one of nine Devonian reef pools connected to the Cooking Lake aquifer. It is a dolomitized bioherm reef with a maximum original oil zone of 648 feet. The pool was considered an ideal candidate for a miscible displacement process because of its vertical relief, small areal extent and the absence of any barriers that would be detrimental to displacement of the slug. This paper reviews the implementation, monitoring techniques and performance of the miscible flood scheme. Introduction The Wizard Lake D-3A pool, located 55 kilometres (35 miles) southwest of Edmonton, as shown in Figure 1, was discovered in April 1951 with the drilling of Texaco Wizard Lake Crown 'B-I in 12-22-48-27-W4M. The pool, drilled on 4D-acre spacing, was fully delineated by the late nineteen fifties. The reservoir is a dolomitized bioherm reef of Devonian age which is part of a prolific chain of Leduc member reefs appropriately known as the Golden Trend. The productive horizon attained a maximum recorded height of 197.5 metres (648 feet) above the Cooking Lake aquifer in which reef growth was initiated. The Cooking Lake aquifer pinches out to the west, but is extensive in the other three directions. This aquifer is very active and is common to other oil and gas accumulations which give rise to interference between pools (Figures 2 and 3). The oil column covered an area of 1,507 hectares (3,725 acres) at the original oil-water contact of 1,230 metres subsea (4,034 feet subsea). Figure 4 presents a structure contour map of the top of the pool based on the gross reef section. The initial oil-in-place is estimated to be 61,200,000 m3 (385 MMSTB), with some 6.5 × 109 m3 (231 bcf) of solution gas dissolved in it. The primary recovery mechanism, identified as a combination of gas expansion, water drive and gravity segregation, was allowed to continue until 1969, when a slug-type hydrocarbon miscible scheme was initiated (Fig. 5). In 1965, a secondary gas cap began to form and by the end of 1969 there existed a 24-metre (78-foot) gas column containing approximately 152 × 106 m3 (5.4 Bcf). Also, by 1969 the oil-water contact had risen by 15 metres (50 feet); leaving an relatively small quantity of available core and thus a method had to be developed to Overcome this shortcoming and also handle the edge effect on porosity that is characteristic of reef pools(1).

Summary An aquifer-influence function (AIF) can be calculated from a gas reservoir's production and pressure histories. The AIF is unique for an aquifer and can be analyzed to determine aquifer size and other information. Two AIF type curves were developed for aquifers with partially sealing faults and then applied to 32 U.S. gulf coast gas reservoirs.

AbstractIncreasing resource scarcity and what has been called “the end of cheap nature” are prompting policymakers and scholars to foster more circular economies to reduce waste and lengthen the lifespan of material goods. Our essay critically examines the political and economic relationships between urban and rural geographies in the context of secondhand economies. Practices of bartering, swapping, selling, and repairing used goods have long been important to rural people and places, but the increasing commodification of discards risks upending rural livelihoods and ways of being as goods move toward urban centers. We explore the relationship between rural and urban reuse economies and suggest how future scholars of rural North America might contribute to strengthening and supporting localized reuse practices.

AbstractAutotrophs play an essential role in the cycling of carbon and nutrients, yet disease‐ecosystem relationships are often overlooked in these dynamics. Importantly, the availability of elemental nutrients like nitrogen and phosphorus impacts infectious disease in autotrophs, and disease can induce reciprocal effects on ecosystem nutrient dynamics. Relationships linking infectious disease with ecosystem nutrient dynamics are bidirectional, though the interdependence of these processes has received little attention. We introduce disease‐mediated nutrient dynamics (DND) as a framework to describe the multiple, concurrent pathways linking elemental cycles with infectious disease. We illustrate the impact of disease–ecosystem feedback loops on both disease and ecosystem nutrient dynamics using a simple mathematical model, combining approaches from classical ecological (logistic and Droop growth) and epidemiological (susceptible and infected compartments) theory. Our model incorporates the effects of nutrient availability on the growth rates of susceptible and infected autotroph hosts and tracks the return of nutrients to the environment following host death. While focused on autotroph hosts here, the DND framework is generalizable to higher trophic levels. Our results illustrate the surprisingly complex dynamics of host populations, infection patterns, and ecosystem nutrient cycling that can arise from even a relatively simple feedback between disease and nutrients. Feedback loops in disease‐mediated nutrient dynamics arise via effects of infection and nutrient supply on host stoichiometry and population size. Our model illustrates how host growth rate, defense, and tissue chemistry can impact the dynamics of disease–ecosystem relationships. We use the model to motivate a review of empirical examples from autotroph–pathogen systems in aquatic and terrestrial environments, demonstrating the key role of nutrient–disease and disease–nutrient relationships in real systems. By assessing existing evidence and uncovering data gaps and apparent mismatches between model predictions and the dynamics of empirical systems, we highlight priorities for future research intended to narrow the persistent disciplinary gap between disease and ecosystem ecology. Future empirical and theoretical work explicitly examining the dynamic linkages between disease and ecosystem ecology will inform fundamental understanding for each discipline and will better position the field of ecology to predict the dynamics of disease and elemental cycles in the context of global change.

Abstract Worldwide the search for new raw materials that are suitable for the production of energy pellets is increasing. Each new raw material undergoes evaluation through various analytical processes and quality assessments before being considered for use as energy pellet. In recent times, the raw materials such as agricultural, forestry, and food waste, as well as the surpluses originating from the agri-food production have become very popular for the production of energy pellets. In this study, we evaluated the feasibility of using lignocellulosic raw materials such as chamomile waste, birch sawdust, pea waste, and soybean waste for the production of pellets. In this study, we focused on the production of thermal energy from pellets by assessing the pellets in accordance with the required standards. The results have shown that lignocellulosic raw materials can be used to produce good quality energy pellets. The proportion of individual raw materials determines the individual strength characteristics of pellets and the suitability of pellets to produce thermal energy.