Evaluation of industrial waste black cumin (Nigella Sativa) for biohydrogen production without pretreatment

Environment, Development and Sustainability - The depletion of fossil fuels and the fact that fossil fuels pollute the environment accelerated the trend toward environmentally friendly energy...     

Biofuels and their connections with the sustainable development goals: a bibliometric and systematic review

Environment, Development and Sustainability - Renewable energy is crucial nowadays, and among the options, biofuels are evidenced as a promising alternative to reduce the dependence of fossil...     

Energy efficiency and conservation for individual Americans

Americans make up only 4% of the world population, yet currently consume 25% of the world’s fossil fuels. The U.S. imports 63% of its oil and it is predicted that by 2020 the U.S. will be importing 95% of its oil resources. Over the past century, ample and affordable supplies of fossil fuels have powered the growth and prosperity of the economies of the US and other countries. Within this century, world oil supplies will decline while demand is projected to continue to increase, suggesting that we will have to transition to different fuels or become much more energy efficient or both. Looking ahead to the near decades, estimates are that consumers will have to reduce their energy use by at least 50%. This reduction will be necessary in large part due the decline in the availability of conventional oil and gas, but also because the U.S. population will continue to grow in number. Although government action is important, individuals too often discount their ability to make significant contributions to solving such major problems. This investigation identifies how informed and concerned individuals can collectively conserve fossil energy. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. An erratum to this article can be found at     

麻疯树种子油生命周期的经济、环境与能量效率

要成为化石能源的有效替代品，生物燃料必须能提供净能量收益，能产生环境效益，具有经济效率，且在大量生产的情况下不引起粮食危机。麻疯树作为第二代生物柴油的重要原料作物，在国内得到大力推广，但实际效率尚不清楚。基于将麻疯树种子油与化石柴油直接混合使用的技术选择，利用生命周期评估法分析了麻疯树种子油生命周期的经济、环境和能量效率。结果表明：（1）在当前产量和生产技术水平下，生产和使用麻疯树种子油的财务净现值为负，要促进麻疯树种子油的生产，需要每年为种子生产者提供8817 元/hm2以上的补贴，为榨油厂商提供268 元/L的补贴；（2）生产和使用每升麻疯树种子油可减少约13 kgCO2当量的温室气体排放，固碳价值为补贴生产提供了部分经济依据，但是仅考虑种子油和固碳的价值时，生产和使用麻疯树种子油尚不具有经济可行性；（3）当仅考虑种子油的能量产出时，只有当种子产量达到795 kg/hm2以上才具有能量效率；当把树枝和果壳等所包含的生物质能计算在内时，在较低种子产量的情况下，也具有显著的能量效率。敏感性分析表明，随着麻疯树种子产量的增加，财务净现值趋于下降，但是种子油的成本下降，减排温室气体的贡献和能量效率都增加。最后，基于麻疯树种子油的生命周期分析，提出了提高经济、环境和能量效率的途径。〖     

Movement towards a low carbon emitted environment: a test of some factors in Malaysia

There exists a high global concern in different nations on environmental sustainability especially at the focal stage of increased economic growth and development process due to high level of environmental degradation and pollution. The major aim of this study was to empirically examine how to minimise carbon emissions (CO₂) in Malaysia which are mainly caused by energy production, fossil fuel consumption, population density and economic growth. The study adopted the method of autoregressive distributed lag bound testing approach to analyse the data for the period 1971–2011. The study found that economic growth in Malaysia has a direct relationship with CO₂ emissions in both the short run and the long run. Similarly, there is a positive relationship between fossil fuel consumption and CO₂ emissions over the same period. Population density was found to have positive impacts on CO₂ emissions. Contrarily, the relationship between the activities of energy production and pollution is negative in the long run. The study recommends that a targeted GDP growth rate should be set with the consideration to avoid more environmental pollution. In addition, the positive impact of fossil fuel consumption on the environmental pollution implies that there is a need to make and implement policies that will encourage the use of public transportation system more than private transportations. That is, the unnecessary use of private vehicles should be discouraged in order to reduce the extent of fossil fuel consumption.     

Man-made and natural smog in California

The radiocarbon content in creosote bush in the greater Los Angeles area has been found to reflect the distribution of smog. Indications are that smog in the even larger air basin of the San Joaquin Valley of California may be caused in part by recent biospheric emissions rather than by fossil fuel combustion alone.     

Variations of anthropogenic CO2 in urban area deduced by radiocarbon concentration in modern tree rings

Radiocarbon concentration in the atmosphere is significantly lower in areas where man-made emissions of carbon dioxide occur. This phenomenon is known as Suess effect, and is caused by the contamination of clean air with non-radioactive carbon from fossil fuel combustion. The effect is more strongly observed in industrial and densely populated urban areas. Measurements of carbon isotope concentrations in a study area can be compared to those from areas of clear air in order to estimate the amount of carbon dioxide emission from fossil fuel combustion by using a simple mathematical model. This can be calculated using the simple mathematical model. The result of the mathematical model followed in this study suggests that the use of annual rings of trees to obtain the secular variations of 14C concentration of atmospheric CO2 can be useful and efficient for environmental monitoring and modeling of the carbon distribution in local scale.     

Land use and energy scenarios affecting the global carbon cycle

Past increase of atmospheric CO₂ involves significant contributions from both fossil and biospheric sources. The latter are controversial, partly because these CO₂ releases may be balanced by accelerated regrowth following clearing of some forests, while others were being converted to agricultural or other nonforest land. A simulation model was used to reconstruct changes since 1860 and project four hypothetical future scenarios of CO₂ injection to 2460. Nineteen compartments and their exchanges of carbon were considered. Areal extents of tropical forests, other wooded ecosystems, and nonforests were incorporated into the model. Rapidly and slowly exchanging pools of carbon per unit area were projected by integrating income-loss differential equations numerically. Estimated cumulative releases of CO₂ from fossil fuels (plus cement) near 120 Pg of carbon (1 Pg = 10¹⁵ g) from 1860 to 1970 were assumed to equal the prompt plus delayed releases due to forest clearing. Limits of exploitable forest area and biomass were evaluated and found to contribute much less future CO₂ than usable fossil fuels. Ultimate release from the latter (7500±2500 Pg C) could increase atmospheric CO₂ manyfold: doubling the assumed 1860 levels as early as (1) the year 2032 for assumed early fossil-use scenarios and (2) the year 2045 for late fossil-use scenarios. Depending on the poorly known parametes that were programmed to constrain the organic production rates, cumulative storage, and the response of plants and soils to enhanced atmospheric CO₂, biospheric storage might reach higher levels for all scenarios than the estimates given here. However, maximizing such storage in real life would require much closer understanding and wiser management of ecosystems than history has shown.     

Carbon isotopes and sulphur contents as indicators of atmospheric pollution from burning fossil fuels

This paper summarized the study carried out in Krakow, Poland in 1975-76 on the estimated local air pollution as measured by carbon isotopes and total sulphur measurement in plants. Good correlation was found between δ¹⁴C value and the total sulphur (measured by radionuclide excited X-ray fluorescence) in beech leaves collected in the late summer, indicating the common source of both pollutants. Sampling and measurement of σ¹³C in atmospheric CO₂ has shown that σ³C can be used as a pollution indicator only in the winter period when no fluctuations exist ddue to plant respiration. A method of CO₂ sampling using molecular sieve proved to be feasible for instantaneous sampling with no isotope fractionation. The highest pollution by fossil CO₂ was measured in winter (12.8% excess. During spring and summer the average contribution of fossil CO₂ was 4.5 to 5.6%.     

生态足迹方法的理论解析

论文系统地解析了生态足迹概念，在简要介绍生态足迹账户框架建立的假设条件，计算方法的基础上，系统总结了生态足迹最近的国际研究进展。同时，重点介绍了生态足迹计算中容易引起误解和疏忽的两个问题：化石能源用地的处理，均衡因子和产量因子的计算。在此基础上，从生态足迹计算过程中化石能源的处理和“利息”的处理两个角度评价了生态足迹方法的局限性。同时从贸易的处理缺乏可持续性基础，忽视国家和区域尺度上空间地理情况的差异，忽视人类社会对自然资产“利息”流的积累和储存，忽视自然资产存量的状况四个角度，分析了生态足迹在不同尺度上应用中存在的问题，最后通过将生态足迹分析还原到IPAT等式，并从热力学和生态经济学的角度解释了现有生态足迹分析政策建议少并且雷同、及其政策建议缺乏可操作性的实质价值的原因。     

Dynamics of species and species complexes as a field of research in historical ecology

Specific features of research on the dynamics of species and species complexes are considered on the basis of data on Late Cenozoic subfossil and fossil bone remains. Special attention is given to the objects to be reconstructed, the principles of their classification, and the concept concerning three scales of these dynamics: the actual, historical, and evolutionary scales. Published in Russian in Ekologiya, 2006, No. 6, pp. 452–456. The text was submitted by the author in English.     

中国碳捕集、利用与封存技术研发与示范

碳捕集、利用与封存(CCUS)是一项新兴的、具有大规模减排潜力的技术,有望实现化石能源使用的CO2近零排放,被认为是进行温室气体深度减排最重要的技术路径之一.开展CCUS技术的研发和储备,将为中国未来温室气体减排提供一种重要的战略性技术选择,受到政府、企业和学术界的广泛关注.本文从CCUS技术产生和发展的背景出发,概括了该技术的特点及存在的主要同题,总结了当前中国CCUS技术政策,介绍了中国CCUS技术研发、试点示范、国际合作等的开展情况,并通过与欧美等发达国家CCUS技术发展与示范活动现状的对比,初步分析了中国CCUS技术发展方面存在的主要不足.为进一步推动我国CCUS技术的研发与示范,文章提出应加强国家层面的技术政策指导和宏观协调、引导资源有效配置;推动建设行业间的CCUS技术合作平台;重视CCUS来来技术应用软环境建设等有针对性的建议.     

Variations of anthropogenic CO2 in urban area deduced by radiocarbon concentration in modern tree rings

Radiocarbon concentration in the atmosphere is significantly lower in areas where man-made emissions of carbon dioxide occur. This phenomenon is known as Suess effect, and is caused by the contamination of clean air with non-radioactive carbon from fossil fuel combustion. The effect is more strongly observed in industrial and densely populated urban areas. Measurements of carbon isotope concentrations in a study area can be compared to those from areas of clear air in order to estimate the amount of carbon dioxide emission from fossil fuel combustion by using a simple mathematical model. This can be calculated using the simple mathematical model. The result of the mathematical model followed in this study suggests that the use of annual rings of trees to obtain the secular variations of ¹⁴C concentration of atmospheric CO₂ can be useful and efficient for environmental monitoring and modeling of the carbon distribution in local scale.     

pH of seawater

The pH of seawater is a key quantity for the calculation of fossil fuel carbon dioxide transfer into the oceans and of the potential dissolution of calcareous organisms, a sink for the carbon dioxide. Thus, it is important to clarify what is meant by the pH of seawater. New data on chloride interactions with hydrogen ions affects this meaning and is discussed briefly in this work.     

Carbon dioxide and climate: Comparison of one- and three-dimensional models

Calculations indicate that there may be a potential climatic problem due to the release of CO₂ from burning fossil fuels. However there is insufficient scientific evidence to predict the impact because the available models are not well enough understood and do not take into account many feedback mechanisms. Therefore, we have calculated atmospheric temperature changes versus latitude with the simpler Manabe-Wetherald radiative-convective model and compared it to the results of their general circulation model. In addition, we have determined the changes in several physical quantities, such as cloud abundance and surface albedo, required to compensate the temperature rise related to increased CO₂ concentrations.     

Ethanol From Corn: Clean Renewable Fuel for the Future,or Drain on Our Resources and Pockets?

It is shown here that one burns 1 gallon of gasoline equivalent in fossil fuels to produce 1 gallon of gasoline equivalent as ethanol from corn. When this corn ethanol is burned as a gasoline additive or fuel, its use amounts to burning the same amount of fuel twice to drive a car once. Therefore, the fuel efficiency of those cars that burn corn ethanol is halved. The widespread use of corn ethanol will cause manifold damage to air, surface water, soil and aquifers. The overall energy balance of corn conversion to ethanol demonstrates that 65% of the input energy is lost during the conversion. Carbon dioxide sequestration by corn is nullified when corn ethanol is burned, and there will be additional carbon dioxide, nitrous oxides, and sulfur oxide emissions from the fossil fuels used to produce the ethanol. Students in the Spring 2003 CE24 Freshman Seminar offered at U.C. Berkeley by the Civil and Environmental Engineering Department Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Radioactivity in fossils at the Hagerman Fossil Beds National Monument

Since 1996, higher than background levels of naturally occurring radioactivity have been documented in both fossil and mineral deposits at Hagerman Fossil Beds National Monument in south-central Idaho. Radioactive fossil sites occur primarily within an elevation zone of 900-1000 m above sea level and are most commonly found associated with ancient river channels filled with sand. Fossils found in clay rich deposits do not exhibit discernable levels of radioactivity. Out of 300 randomly selected fossils, approximately three-fourths exhibit detectable levels of natural radioactivity ranging from 1 to 2 orders of magnitude above ambient background levels when surveyed with a portable hand held Geiger-Muller survey instrument. Mineral deposits in geologic strata also show above ambient background levels of radioactivity. Radiochemical lab analysis has documented the presence of numerous natural radioactive isotopes. It is postulated that ancient groundwater transported radioactive elements through sand bodies containing fossils which precipitated out of solution during the fossilization process. The elevated levels of natural radioactivity in fossils may require special precautions to ensure that exposures to personnel from stored or displayed items are kept as low as reasonably achievable (ALARA).     

Energy futures and green chemistry: competing for carbon

Global energy demand is expected to increase from the current 400 ExaJ per year to as much as 700–1,000 ExaJ per year by the middle of this century. If fossil carbon resources continue to make up the bulk of the energy supply, not only will atmospheric carbon dioxide increase to levels not seen for the past 30–35 million years, but depleting fossil carbon resources will become increasingly less available for other purposes, particularly the production of chemicals on which society now depends. The chemical process industries are heavily dependent on the availability of low-price petroleum as a feedstock. Recent life-cycle analyses suggest that pursuing both strategies of renewable energy sources and renewable feedstocks (i.e. biomass) will be required to meet these competing demands. Reducing the global use of both energy and manufactured chemicals will be a challenge for sustainable development. Education of the next generation of chemists and chemical engineers will have to change significantly from its current emphasis on petrochemical-based manufacturing to include a much greater emphasis on renewable resources and bio-based processes.Brief accounts of this work were presented at the 7th International Symposium on Green Chemistry in China (Zhuhai, People’s Republic of China, May 2005) and at the Joint US–China Green Chemistry Workshop (Beijing, People’s Republic of China, May 2005; this workshop was supported by US National Science Foundation grant CHE-0522369).     

Modulation of fossil fuel production by global temperature variations

An analysis of the fossil fuel production record since 1860 shows that the exponential growth in production is modulated in the inverse sense by variations in global average temperature. Taking this modulation into account shows that the underlying rate of increase is about 25% less than the widely quoted 4.3% annual rate. This modulation may also produce a partially ameliorating feedback if the often predicted carbon dioxide greenhouse effect actually materializes.