Combustion and emission characteristics of a direct injection CI engine when operated on Marotti oil methyl ester and blends of Marotti oil methyl ester and diesel

This paper presents a feasibility study of Marotti oil biodiesel as an alternative to diesel fuel for a compression ignition engine. Marotti oil is inedible and available mainly in the state of Kerala. The oil is extracted from Marotti seeds. However, the high viscosity, poor volatility and cold flow characteristics of many vegetable oils in general, and Marotti oil in particular, can cause problems such as injector coking, severe engine deposits, filter gumming, piston ring sticking and thickening of lubrication from long-term use in diesel engines. These problems can be eliminated or minimised by transesterification of the vegetable oils to form monoesters. Although transesterification improves the fuel properties of vegetable oil, the viscosity and volatility of biodiesel are still worse than for petroleum diesel fuel. Subsequently, Marotti oil was converted into its methyl ester by the process of transesterification. The methyl ester was blended with diesel in various proportions to obtain different blends of Marotti oil with diesel. The performance, emission and combustion characteristics of Marotti methyl ester and its blends with diesel were studied and the results were compared with the base line data generated for diesel operation. Experiments were conducted using an injection timing of 23° before top dead centre (BTDC) and an injection pressure of 205 bar at various power outputs and at a constant rated speed of 1500 rpm. The engine manufacturer specifies an injection timing of 23° BTDC and injection pressure of 205 bar for the standard diesel fuel operation. The heat release rates, maximum rate of pressure rise, ignition delay and combustion duration for these fuel combinations were obtained.

From the results obtained, it was observed that the biodiesel produced from Marotti oil and its blends with diesel have slightly reduced brake thermal efficiency and increased smoke, hydrocarbon, carbon monoxide and reduced NO _x emissions compared with diesel-only operation. The investigation showed that the B20 biodiesel blend of Marotti oil with diesel produced better performance in terms of higher brake thermal efficiency, lower specific fuel consumption and comparatively lower emissions compared to the other blend ratios considered.     

Combustion and emission characteristics of a direct injection,compression‐ignition engine when operated on Honge oil,HOME and blends of HOME and diesel

This paper reports the results of research conducted to study the fuel properties of Honge oil and blends of its ester and the subsequent testing of these oils in a four‐stroke, single cylinder, water‐cooled, direct injection, compression‐ignition (CI) engine. Experiments were conducted with injection timings of 19, 23 and 27° BTDC at various loads and at a constant rated speed of 1500?rev?min^?1. The performance and emission characteristics of Honge oil and Honge oil methyl ester (HOME) blended with diesel, to produce blends designated B20, B40 and B80, were studied. The heat release rates, maximum rate of pressure rise, ignition delay, and combustion duration for these fuel combinations were determined.     

Potential of Marine Reserves to Cause Community-Wide Changes beyond Their Boundaries

Abstract:  Fishing and other human activities can alter the abundances, size structure, and behavior of species playing key roles in shaping marine communities (e.g., keystone predators), which may in turn cause ecosystem shifts. Despite extensive evidence that cascading trophic interactions can underlie community-wide recovery inside no-take marine reserves by protecting high-level predators, the spatial extent of these effects into adjacent fished areas is unknown. I examined the potential for community-wide changes (i.e., the transition from overgrazed coralline barrens to macroalgal beds) in temperate rocky reefs within and around a no-take marine reserve. For this purpose I assessed distribution patterns of predatory fishes, sea urchins, and barrens across the reserve boundaries. Predatory fishes were significantly more abundant within the reserve than in adjacent locations, with moderate spillover across the reserve edges. In contrast, community-wide changes of benthic assemblages were apparent well beyond the reserve boundaries, which is consistent with temporary movements of predatory fishes (e.g., foraging migration) from the reserve to surrounding areas. My results suggest that no-take marine reserves can promote community-wide changes beyond their boundaries.     

全氟辛烷磺酸盐(PFOS)替代品对中国白羽鹌鹑的毒性

为研究全氟辛烷磺酸盐(perfluorooctane sulfonate,PFOS)替代品对环境生物的毒害效应,选用中国白羽鹌鹑作为受试生物,建立其环境危害评价毒性测试方法,并对PFOS替代化学品进行了急性经口、急性饲喂及繁殖毒性的风险评价。结果表明,全氟丁基有机铵盐阳离子表面活性剂急性经口毒性实验的LD50为500.44mg·kg-1,其余3种替代化学品在上限浓度2000mg·kg-1,白羽鹌鹑均未出现明显死亡,4种PFOS替代品对中国白羽鹌鹑的急性经口毒性均为低毒。全氟丁基有机铵盐阳离子表面活性剂急性饲喂毒性实验的LC50为970.50mg.kg-1,对白羽鹌鹑的饲喂毒性为中毒,而其余3种替代化学品在上限浓度5000mg·kg-1,白羽鹌鹑均未出现明显死亡,对中国白羽鹌鹑的急性饲喂毒性为低毒。在长期饲喂过程中,织物三防整理剂和C6织物三防整理剂会表现出一定的生殖毒性,造成中国白羽鹌鹑的孵化率降低,胚胎死亡率及未受精率升高;全氟丁基有机铵盐阳离子表面活性剂会影响到中国白羽鹌鹑的未受精率,C4织物三防整理剂未表现出明显的生殖毒性。     

四川省森林生态系统对野生珍稀濒危动物的保护价值计量研究

论文以异地保护成本替代法计算森林生态系统对濒危野生动物的保护价值。栖息于四川省森林生境的濒危野生动物需要生存下去所必需的食物、水、居住环境等一切生存条件完全由人为提供、人为创造和维持的成本就是四川省森林生态系统保护这些野生动物的价值。论文以动物园饲养动物的基本成本作为濒危野生动物异地保护的核算依据,得到四川省森林生态系统对野生珍稀濒危动物的保护价值为15.45×10⁸元/a。     

EXPERIENCE WITH THE 303-208-201 STUDY RELATIONSHIPS1

ABSTRACT: The current 201 study by the Bergen County Sewer Authority illustrates possibilities for improving the currently defined relationships between 201, 208 and 303 studies. The Bergen County Sewer Authority serves 115 square miles in northeast New Jersey, providing sewerage service to 507,000 people in 43 municipalities. Its STP discharges to the Hackensack River, a tidal estuary recently classified as Water Quality Limited, and which receives significant non-plant loading. The subject 201 study is concurrent with 208 and 303 planning by NJDEP. Preliminary evaluations show that detailed 201 work can affect the conclusions of 303 and 208 studies, and that a wider (environmental - social as well as economic) interpretation of cost-effectiveness can demand re-examination of prior assumptions and decisions, a task not typically part of 208–303 work. Increased flexibility is needed in applying 303 and 208 recommendations to defining 201 studies and NPDES permit criteria, particularly in analysis of water use objectives, water quality parameters and future flows, loadings and facility costs. Further, perception of alternatives can be clarified by broadening analysis of costs and control and plant strategies. Inclusion of 201 planning at all stages of regional planning can synergistically improve the total planning process.     

LOCAL ATTITUDES TOWARD ALTERNATIVE USES OF A RESERVOIR PROJECT1

ABSTRACT: The purpose of this paper is to examine the correlates of attitudes toward alternative uses which could have been made of public resources employed to construct a multipurpose reservoir. A sample of 303 adult residents of a rural community impacted by lake construction was asked to evaluate several alternative development options which could have been implemented in lieu of the lake project. The alternative options evaluated were: rural industrialization, keeping land in agriculture and forests, improving public services, building a state or national park, drilling water wells for urban water supply, aid to small business, helping poor people, building several smaller impoundments, and private recreation development. The findings revealed the local people preferred the lake project to every option except keeping the land in agriculture and forest. Even this option was not strongly supported when compared with the lake project. Socio-demographic, attitude, and cost assessment factors were investigated using a “vested interest” perspective for hypotheses development. These findings demonstrated that costs and benefits were relatively good predictors of attitudes toward alternative development options and were supportive of the theoretical perspective advanced in this paper.     

Thought for Fuelling Change: A Review of Three Models for Understanding Environmentally Significant Transitions

For over a century, western economic development has depended upon the use of combustible hydrocarbons for its energy needs. The 20th century saw the prolific exploitation of fossil hydrocarbon sources (coal and oil) which are finite and exhaustible. There is a clear need for society to conserve such non-renewable resources. In addition to conservation, a wholesale switch to renewable energy sources should be seen as the first research and development priority. In the interim, moving towards a crop-based fuel economy appears to be a good alternative to provide the necessarily dramatic changes in lifestyle and mindset that would be required of consumers, for a wholesale shift away from hydrocarbon combustion. Before programs and policies designed to address the need for an interim or alternative energy and materials economy are put into place however, it is important to understand the barriers and opportunities put forth by society itself. Conventional frameworks designed to understand this type of change are of limited assistance. This paper argues that institutional thinking is a very useful tool in addressing these types of environmental problems.     

城市交通低碳化的可能路径

对中国如何发展城市交通低碳化进行了战略构想,从空间性减碳、技术性减碳和社会性减碳三方面着眼提出了可行性建议。