2,481 research outputs found
The effects of biochar as a soil amendment on soil quality and plant growth
Biochar is a stable form of recalcitrant carbon created by heating biomass in a low or no oxygen environment. When used as a soil amendment, biochar forms a dynamic substrate which provides numerous benefits, including increasing nutrient availability, increasing soil water retention, improving crop yield, and sequestering carbon for hundreds to thousands of years. However, biochar\u27s effectiveness largely depends on the biomass feedstock and the soil to which it is applied. Individual biochars made from different feedstocks perform differently against each other, and the magnitudes of their effects can be dependent on many factors within the soil. Testing different feedstocks under different soil conditions is needed in order to gain a full picture of the potential of biochar.
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Systems Approach and Quantitative Decision Tools for Technology Selection in Environmentally Friendly Drilling
One of the petroleum industry?s goals is to reduce the environmental impact of oil and gas operations in environmentally sensitive areas. To achieve this, a number of Environmentally Friendly Drilling (EFD) technologies have been developed to varying degrees. For example, the use of an elevated platform as an alternative to the gravel pad is less intrusive and leads to a more environmentally friendly approach to drilling operations. Elevated drilling platforms will require the use of piles. Another alternative to the gravel pad is the use of composite mats. Since the demand of low impact technologies for drill site construction has rapidly increased, the parametric study for the feasibility of using pile foundations and composite mats is conducted in this research.
Even though a number of EFD technologies have already been developed to varying degrees, few have been integrated into a field demonstrable drilling system (i.e., combination of technologies) compatible with ecologically sensitive areas. In general, it is difficult to select the best combination of EFD technologies for a given site because there are many possible combinations and many different evaluation criteria. The proposed technology evaluation method is based on a systems analysis that can be used for integrating current and new EFD technologies into an optimal EFD system. An optimization scheme is suggested based on a combination of multi-attribute utility theory and exhaustively enumerating all possible technology combinations to provide a quantitative rationale and suggest the best set of systems according to a set of criteria, with the relative importance of the different criteria defined by the decision-maker. In this research, the sensitivity of the optimal solution to the weight factors and the effects of the uncertainty of input scores are also discussed using a case study.
An application of the proposed approach is described by conducting a case study in Green Lake at McFaddin, TX. The main purpose of this case study is to test the proposed technology evaluation protocol in a real site and then to refine the protocol. This research describes the results of the case study which provided a more logical and comprehensive approach that maximized the economic and environmental goals of both the landowner and the oil company leaseholder
Design and Implementation of a Storage Management Method for Content Distribution
The SMART system is a special purpose server developed by ETRI and designed for efficient streaming services over high speed networks. The SMART server has one or more special purpose NS (Network-Storage) card. The NS card has several disks that store multimedia contents. However all of the multimedia contents to be serviced cannot be stored at the server. In this paper, we will describe the storage management mechanism in design and implementation aspects. With this storage management mechanism, the SMART server can provide effectiveness in managing storage and distributing some contents from a source station to streaming service servers
Green synthesis of gamma-valerolactone (GVL) through hydrogenation of biomass-derived levulinic acid using non-noble metal catalysts : A critical review
The distinct physicochemical properties and renewable origin of gamma-valerolactone (GVL) have provided opportunities for diversifying its applications, particularly as a green solvent, excellent fuel additive, and precursor to valuable chemicals. Among the related publications found in the SCOPUS database (≈172 in the last 10 years), we focused our effort to review the conversion of levulinic acid (LA) to GVL over non-noble metal catalysts and the corresponding mechanisms (≈30 publications) as well as the applications of GVL as a solvent, fuel additive, and platform chemical (≈30 publications) mostly in the last five years (some preceding publications have also been included due to their relevance and importance in the field). The use of non-noble metals (e.g., Cu and Zr) presents a greener route of GVL synthesis than the conventional practice employing noble metals (e.g., Pd and Ru), in view of their higher abundance and milder reaction conditions needed (e.g., low pressure and temperature without H 2 involved). The significance of the catalyst characteristics in promoting catalytic transfer hydrogenation of LA to GVL is critically discussed. Structural features and acid-base properties are found to influence the activity and selectivity of catalysts. Furthermore, metal leaching in the presence of water in catalytic systems is an important issue, resulting in catalyst deactivation. Various endeavors for developing catalysts using well-dispersed metal particles along with a combination of Lewis acid and base sites are suggested for efficiently synthesizing GVL from LA
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