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Renewable Resources (renewable + resource)

Distribution by Scientific Domains

Chemistry	34%
Polymers and Materials Science	24%
Life Sciences	24%
Engineering	10%
2 Other Domains	8%

Selected Abstracts

LEARNING BY DOING IN THE PRESENCE OF AN OPEN ACCESS RENEWABLE RESOURCE: IS GROWTH SUSTAINABLE?

NATURAL RESOURCE MODELING, Issue 1 2005
CAROL McAUSLAND
ABSTRACT. We examine the relationship between growth, resource abundance and trade when the natural resource is renewable and open access and there is inter-industry learning by doing. We find growth is not sustainable in the closed economy and can be sustained in the open economy only so long as the labor forced engaged in resource extraction shrinks over time. Comparisons of steady state welfare in autarky and free trade reveal that for very high or low world prices of the resource-based good, it is possible for the economy to gain from trade. However if the price is intermediate, it may instead lose. [source]

RANDOM PENALTIES AND RENEWABLE RESOURCES: A MECHANISM TO REACH OPTIMAL LANDINGS IN FISHERIES

NATURAL RESOURCE MODELING, Issue 3 2009
FRANK JENSEN
Abstract Recent literature considers illegal landings a moral hazard problem that arises because individual landings are unobservable. The literature proposes incentive schemes to solve the information problem. However, most of the proposed schemes raise huge information requirements and social budget balance is not secured. In this paper, we suggest a random penalty mechanism that reduces the information requirements and secures budget balance in the case of a given number of licensed vessels. In the random penalty mechanism, aggregate landings are measured through stock sizes and the natural growth function. If aggregate landings are below optimal landings, each fisherman receives a subsidy. If aggregate catches are above optimal landings, the mechanism works such that either the fisherman is randomly selected and pays a fine or the fisherman is not selected and receives a subsidy. The fine and subsidy can be designed such that budget balance is secured. Provided risk aversion is sufficiently large and the fine is high enough, the random penalty mechanism will generate optimal individual landings. The budget balance combined with risk aversion drives the result for this advanced tax/subsidy system that does not exhaust the resource rents. The budget balance creates interdependence between fishermen that secure optimality. [source]

Green Nanocomposites from Renewable Resources: Biodegradable Plant Oil-Silica Hybrid Coatings

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 12 2003
Takashi Tsujimoto
Abstract Green nanocomposite coatings based on renewable plant oils have been developed. An acid-catalyzed curing of epoxidized plant oils with 3-glycidoxypropyltrimethoxysilane produced transparent nanocomposites. The hardness and mechanical strength improved by incorporating the silica network into the organic polymer matrix, and good flexibility was observed in the nanocomposite. The nanocomposites showed high biodegradability. [source]

New Materials Based on Renewable Resources: Chemically Modified Expanded Corn Starches as Catalysts for Liquid Phase Organic Reactions.

CHEMINFORM, Issue 10 2003
Shinichi Doi
No abstract is available for this article. [source]

Renewable resources , green biorefinery: separation of valuable substances from fluid,fractions by means of membrane technology

BIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 1 2009
Senad Novalin
Abstract The aim of this study is to emphasize the potential of membrane technologies and the specific performance-limiting borders of pressure-driven (microfiltration, ultrafiltration, nanofiltration, reverse ssmosis) as well as electro-membrane (electrodialysis, electrodialysis using bipolar membranes) techniques for the separation of valuable substances from silage press-juice obtained in green biorefineries. Depending on the product, nanofiltration can be considered a partially fractionating technique with great future potential. Electrodialysis turns out to be a suitable separation technique for removing huge amounts of salt and isolating individual valuable substances. However, residual impurities must be taken into account for subsequent separation steps. In any case, further separation processes (e.g. chromatography) must be integrated in future green biorefinery production plants. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd [source]

The relevance of international consortia in studies on the pathogenesis of type 1 diabetes: the role of ET1DGN

DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 3 2006
Flemming Pociot
Abstract The Type 1 Diabetes Genetics Consortium (T1DGC), funded September 2002, is a collaborative effort to develop resources for the purpose of identifying risk genes for type 1 diabetes. One of the aims is to establish a renewable resource of DNA on 2500 affected sib-pair families. Regional networks have been established and in continental Europe, the European Type 1 Diabetes Genetics Network (ET1DGN) is responsible for identifying and collecting families. Most European countries have shown interest in this study and many have started recruiting families. The consortium is open to participation and there are several ways one can participate as a member of the consortium. ET1DGN suggests going beyond the tasks of T1DGC and establishing a well-organized network for additional and future studies in Europe. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Undecylenic acid: A valuable renewable building block on route to Tyromycin,A derivatives

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2008
Marijke Van der Steen
Abstract A key intermediate for the synthesis of Tyromycin,A, a C-20 tetrachlorodicarboxylic acid, was produced in six steps starting with the dimerization of methyl 10-undecenoate which was obtained from a renewable resource, e.g. castor oil. The acyloin condensation product was then oxidized, transformed to the diene, followed by ozonization, chlorination and finally oxidation to the corresponding tetrachlorodicarboxylic acid. [source]

Polymers from renewable resources: Bulk ATRP of fatty alcohol-derived methacrylates

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2008
Gökhan Çayli
Abstract Copper-mediated atom transfer radical polymerization (ATRP) of lauryl methacrylate (LMA) and other long-chain methacrylates was investigated in bulk at 35,°C by using CuCl/N,N,N,,N,,N,, -pentamethyldiethylenetriamine (PMDETA)/tricaprylylmethylammonium chloride (Aliquat®336) as the catalyst system and ethyl 2-bromoisobutyrate (EBIB) as the initiator. The investigated monomers can be derived from fatty alcohols and are therefore an important renewable resource for a sustainable development of our future. The amounts of ligand, Aliquat®336 and CuCl were optimized and the effect of their concentrations on the control of the polymerization and the observed conversions were investigated. It was found that a molar ratio of EBIB/CuCl/Ligand/Aliquat®336 of 1,:,1,:,3,:,1 provided the highest conversions of LMA and the best controlled polymerizations. These optimized conditions allowed for the synthesis of poly(lauryl methcarylate)s with different targeted DP (25, 50, 75, 100, 120, 240, and 500), including high-molecular-weight polymers with narrow molecular weight distributions. In addition, methacrylate monomers were prepared from fatty alcohols (capric, myristic, palmitic, stearic) and polymerized using the developed procedure to obtain polymers with the same DP and different chain lengths (C10, C12, C14, C16, and C18) of pending alkyl groups. Finally, the thermal properties of these polymers were examined by differential scanning calorimetry and thermogravimetric analysis. [source]

Cellulose as a renewable resource for the synthesis of wood consolidants

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010
Giacomo Cipriani
Abstract Crosslinkable cellulose ethers as allyl cellulose, allyl carboxymethyl cellulose, and allyl n -hydroxypropyl cellulose were synthesized and characterized, and their use as consolidating agents for waterlogged wood was studied. For this kind of application, structural properties similar to those of wood's polysaccharide components are desired in the design stage of new consolidants. The choice to synthesize cellulose ethers was determined from the possibility of using cellulose as the starting material because of its large availability in nature, biocompatibility, and low cost. In addition, cellulose ethers are quite easy to obtain, and they can have different properties, depending on the nature and the amount of the functional groups introduced. For this purpose, a cellulose with a lower degree of polymerization was also used for the synthesis of related cellulose ethers. By means of Fourier transform infrared spectroscopy, the affinity of the cellulose derivatives for degraded lignin flours was detected. The preliminary results of this study show that these polysaccharide compounds may be proposed as wood consolidating agents. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Use of ionic liquids for the efficient utilization of lignocellulosic materials

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2008
Shengdong Zhu
Abstract Lignocellulosic materials are the most abundant renewable resource in the world and their efficient utilization provides a practical route to maintain social sustainable development. Application of ionic liquids has opened new avenues for the efficient utilization of lignocellulosic materials in such areas as fractionation, preparation of cellulose composites and derivatives, analysis, and removal of pollutants. However, there are still many challenges in putting these potential applications into practical use, for example, the high price of ionic liquids and lack of basic physico-chemical and toxicological data. Further research and financial support are required to address such challenges. Copyright © 2008 Society of Chemical Industry [source]

Development of renewable resource,based cellulose acetate bioplastic: Effect of process engineering on the performance of cellulosic plastics

POLYMER ENGINEERING & SCIENCE, Issue 5 2003
A. K. Mohanty
This paper deals with the development of a cellulose acetate biopolymer. Plasticization of this biopolymer under varying processing conditions to make it a suitable matrix polymer for bio-composite applications was studied. In particular, cellulose acetate was plasticized with varying concentrations of an eco-friendly triethyl citrate (TEC) plasticizer, unlike a conventional, petroleum-derived phthalate plasticizer. Three types of processing were used to fabricate plasticized cellulose acetate parts: compression molding, extrusion followed by compression molding, and extrusion followed by injection molding. The processing mode affected the physicomechanical and thermal properties of the cellulosic plastic. Compression molded samples exhibited the highest impact strength, tending towards the impact strength of a thermoplastic olefin (TPO), while samples that were extruded and then injection molded exhibited the highest tensile strength and modulus values. Increasing the plasticizer content in the cellulosic plastic formulation improved the impact strength and strain to failure while decreasing the tensile strength and modulus values. The coefficient of thermal expansion (CTE) of the cellulose acetate increased with increasing amounts of plasticizer. Plasticized cellulose acetate was found to be processable at 170,180°C, approximately 50°C below the melting point of neat cellulose acetate. [source]

Bioethanol from agricultural waste residues

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2008
Pascale Champagne
Abstract Under the Kyoto Protocol, the Government of Canada has committed to reducing its greenhouse gas emissions by 6% from 1990 levels between 2008 and 2012. Ethanol-blended gasolines have the potential to contribute significantly to these emission reductions. Ethanol is derived from biologically renewable resources and can be employed to replace octane enhancers and aromatic hydrocarbons or oxygenates. To date, the ethanol production industry in Canada is comprised mainly of small-scale plants producing ethanol primarily from agricultural crops as feedstock. Research interests in the area of bioethanol production from organic waste materials emerged in the late 1980. Significant advances in lignocellulosic material extraction and enzymatic hydrolysis have been reported in the last decade, however, continued research efforts are essential for the development of technically feasible and economically viable large-scale enzyme-based biomass-to-ethanol conversion processes. This research aims to develop and test an enzyme-based biomass-to-ethanol conversion process, which employs organic waste materials, such as livestock manures, as alternative sources of cellulosic material feedstock. The source of the livestock manure, manure management practices and cellulose extraction procedures have a significant impact on the quantity and quality of the cellulosic materials derived. As such, raw feedstock materials must be carefully characterized to assess the impact of these factors on the yield of bioethanol and residual end products. The success of cellulose-to-ethanol conversion processes for cellulose extracted from these waste materials as feedstock is generally a function of cellulose fiber pretreatment, enzyme selection and operating conditions. These will differ depending on the source of the waste material feedstock. The long-term benefits of this research will be to introduce a sustainable solid waste management strategy for a number of livestock manure and other lignocellulosic waste materials; contribute to the mitigation in greenhouse gases through sustained carbon and nutrient recycling; reduce the potential for water, air, and soil contamination associated with land disposal of organic waste materials; and to broaden the feedstock source of raw materials for the ethanol production industry. © 2007 American Institute of Chemical Engineers Environ Prog, 2008 [source]

A Competitive European Agriculture Designed for the Citizens , Romania's Perspective Une agriculture européenne compétitive au service des citoyens : La perspective de la Roumanie Eine an die Bedürfnisse der Bürger angepasste, wettbewerbsfähige Europäische Landwirtschaft , die Perspektive Rumäniens

EUROCHOICES, Issue 3 2008
Dacian Ciolo
Summary A Competitive European Agriculture Designed for the Citizens , Romania's Perspective In the coming months and years the European Union has to make fundamental choices for the future of agriculture, food, landscape and quality of life within its whole territory. These choices have now to be made for 27 Member States, which together give a new configuration to the Community. Poland and Romania together now represent nearly half of the total active population involved in EU agriculture. European agriculture has to be multifunctional, competitive not only for the market but also for citizens, as an economic activity that uses and manages renewable resources of public interest. Higher competitiveness inevitably leads to restructuring and modernisation of the agro-food sector in the New Member States. This must be achieved gradually to avoid a negative social impact, through a rural development policy supporting job creation outside agriculture. Romanian agriculture employs about 30 per cent of the country's active population and half of the country's population live in rural areas. Romania, therefore, aims to preserve a substantial CAP budget to promote investment in agriculture and quality of life in rural areas. It is in the interest of the whole EU to ensure not just proper use of the productive potential of Romanian agriculture but also economic development of the Romanian countryside. Au cours des prochains mois et des prochaines années, l'Union européenne doit faire des choix fondamentaux quant à l'avenir de l'agriculture, de l'alimentation et de la qualité de vie sur l'ensemble de son territoire. Ces choix relèvent actuellement de 27 état membres qui, ensemble, donnent à la communauté une nouvelle configuration. Actuellement, la Pologne et la Roumanie représentent à elles deux pratiquement la moitié de la population agricole de l'Union européenne. L'agriculture européenne doit être multifonctionnelle et compétitive, pas seulement pour les marchés mais aussi pour les citoyens, en tant qu'activitééconomique qui utilise et gère des ressources renouvelables d'intérêt public. La hausse de la compétitivité entraînera inévitablement une restructuration et une modernisation du secteur agro-alimentaire dans les nouveaux états membres. Ce processus doit être progressif pour éviter des conséquences sociales négatives, et il doit s'accompagner d'une politique de développement rural pour promouvoir la création d'emplois hors du secteur agricole. L'agriculture roumaine emploie environ 30 pour cent de la population active nationale et la moitié de la population du pays vit dans des zones rurales. La Roumanie compte donc utiliser une grande partie du budget de la PAC pour la promotion des investissements dans le secteur agricole et l'amélioration de la qualité de vie dans les zones rurales. Il est dans l'intérêt de l'ensemble de l'Union européenne de s'assurer non seulement que le potentiel productif agricole de la Roumanie est correctement utilisé mais également que la campagne roumaine se développe économiquement. In den kommenden Monaten und Jahren wird die Europäische Union grundlegende Entscheidungen im Hinblick auf Landwirtschaft, Lebensmittel, Landschaftsbild und Lebensqualität zu treffen haben, die sich auf ihr gesamtes Gebiet auswirken werden. Diese Entscheidungen betreffen nun alle 27 Mitgliedsstaaten, die der Gemeinschaft ein neues Gesicht verleihen. Mittlerweile stellen Polen und Rumänien zusammen etwa die Hälfte der aktiv in der Landwirtschaft der EU beschäftigten Bevölkerung. Die europäische Landwirtschaft muss multifunktional und nicht nur mit Blick auf den Markt wettbewerbsfähig sein, sondern auch mit Blick auf ihre Bürger, als ein Wirtschaftszweig, der erneuerbare Ressourcen verwendet und verwaltet, für die ein öffentliches Interesse besteht. Eine höhere Wettbewerbsfähigkeit führt unweigerlich zur Umstrukturierung und Modernisierung des Agro-Food-Sektors in den neuen Mitgliedsstaaten. Zur Vermeidung negativer Auswirkungen auf die Gesellschaft muss dies schrittweise durch eine Politik zur Entwicklung des ländlichen Raums erfolgen, die Arbeitsplätze außerhalb der Landwirtschaft fördert. In Rumänien sind 30 Prozent der Erwerbstätigen in der Landwirtschaft tätig, und die Hälfte der Bevölkerung lebt im ländlichen Raum. Daher ist Rumänien daran gelegen, weiterhin einen hinreichend großen Haushalt für die GAP zu erhalten, um Investitionen in die Landwirtschaft und die Lebensqualität im ländlichen Raum zu fördern. Es ist im Interesse aller EU-Länder, nicht nur die Ausschöpfung des produktiven Potenzials der rumänischen Landwirtschaft, sondern ebenfalls die wirtschaftliche Entwicklung des ländlichen Raums in Rumänien sicherzustellen. [source]

Polymers from renewable resources: Bulk ATRP of fatty alcohol-derived methacrylates

Fluid biomulching based on poly(vinyl alcohol) and fillers from renewable resources

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008
E. Chiellini
Abstract This article reports on the results obtained in an investigation on the application of biodegradable polymeric materials in the agricultural practice of mulching. Particular attention has been devoted to the effect of biobased mulching films generated in situ by low-pressure spraying of polymeric water dispersions on the various cultivars. In a field trial, the effectiveness of the hydromulching (liquid-mulching) technique was assessed by the monitoring of the growth and yield of lettuce and corn, which were used as reference plants. Conventional plastic films and straw mulching (SM) were compared with liquid-mulching treatments based on poly(vinyl alcohol) and natural fillers derived from agroindustrial wastes (sugar cane bagasse, wheat flour, saw dust, and wheat straw). An improvement of the biomass yield of the two selected plants with respect to conventional polyethylene mulching was attained in various liquid-mulching formulations with positive effects on the maintenance of soil structure. Alternative fluid-mulching treatments based on biodegradable components were effective in preserving soil aggregates and improving some crop growth parameters. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Green chemistry for the second generation biorefinery,sustainable chemical manufacturing based on biomass

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2007
James H Clark
The material needs of society are reaching a crisis point. The demands of a growing and developing world population will soon exceed the capacity of our present fossil resource based infrastructure. In particular, the chemical industry that underpins most industries needs to respond to these challenges. The chemical manufacturing and user industries face an unprecedented range and intensity of drivers for change, the greatest of which, REACH (Registration, Evaluation and Authorisation of Chemicals) has yet to bite. In order to address the key issues of switching to renewable resources, avoiding hazardous and polluting processes, and manufacturing and using safe and environmentally compatible products, we need to develop sustainable and green chemical product supply chains. For organic chemicals and materials these need to operate under agreed and strict criteria and need to start with widely available, totally renewable and low cost carbon,the only source is biomass and the conversion of biomass into useful products will be carried out in biorefineries. Where these operate at present, their product range is largely limited to simple materials (e.g. cellulose), chemicals (e.g. ethanol) and bioenergy/biofuels. Second generation biorefineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing, controlled pyrolysis, catalysis in water and microwave activation, in order to make more complex molecules and materials on which a future sustainable society will be based. Copyright © 2007 Society of Chemical Industry [source]

Cell-free ethanol production: the future of fuel ethanol?

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2007
Eric J. Allain
Abstract The production of fuel ethanol from renewable resources as an economically viable alternative to gasoline is currently the subject of much research. Most studies seek to improve process efficiency by increasing the rate of ethanol production; ultimately, this approach will be limited by the selected ethanol-producing microorganism. Cell-free ethanol production, using only the enzymes involved in the conversion of glucose to ethanol, may offer a practical and beneficial alternative. Mathematical modeling of such a system has suggested that a cell-free process should be capable of producing ethanol much more efficiently than the microbial based process. This finding along with other potential benefits of a microorganism-free process suggests that a cell-free process might significantly improve the economy of fuel ethanol production and is a worthy target for further research. Copyright © 2007 Society of Chemical Industry [source]

Biodegradable polymers based on renewable resources.

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2005

Abstract Novel polycarbonates, with pendant functional groups, based on 1,4:3,6-dianhydrohexitols and L -tartaric acid derivatives were synthesized. Solution polycondensations of 1,4:3,6-dianhydro-bis- O -(p -nitrophenoxycarbonyl)hexitols and 2,3-di- O -methyl- L -threitol or 2,3- O -isopropylidene- L -threitol afforded polycarbonates having pendant methoxy or isopropylidene groups, respectively, with number average molecular weight (Mn) values up to 3.61 × 104. Subsequent acid-catalyzed deprotection of isopropylidene groups gave well-defined polycarbonates having pendant hydroxyl groups regularly distributed along the polymer chain. Differential scanning calorimetry (DSC) demonstrated that all the polycarbonates were amorphous with glass transition temperatures ranging from 57 to 98 °C. Degradability of the polycarbonates was assessed by hydrolysis test in phosphate buffer solution at 37 °C and by biochemical oxygen demand (BOD) measurements in an activated sludge at 25 °C. In both tests, the polycarbonates with pendant hydroxyl groups were degraded much faster than the polycarbonates with pendant methoxy and isopropylidene groups. It is noteworthy that degradation of the polycarbonates with pendant hydroxyl groups was remarkably fast. They were completely degraded within only 150 min in a phosphate buffer solution and their BOD-biodegradability reached nearly 70% in an activated sludge after 28 days. The degradation behavior of the polycarbonates is discussed in terms of their chemical and physical properties. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3909,3919, 2005 [source]

Quality Concepts for the Improved Use of Recycled Polymeric Materials: A Review

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2008
Francisco Vilaplana
Abstract Polymeric waste materials should be considered resources for the manufacture of new products through recycling processes, with a similar status to virgin fossil-based plastics and biopolymers from renewable resources. Several efforts can be made to achieve this qualitative quantum leap in plastics recycling, and consequently introduce recycled products, with competitive performance, to the market. Scientific knowledge about the degradation processes during the life cycle and the development of fast and reliable analytical methods for the quality assessment of recycled plastics are fundamental to guarantee their performance in new applications. Different strategies,restabilisation, rebuilding, compatibilisation, and addition of elastomers and fillers,can be used to upgrade the structure and properties of polymeric waste streams. This review discusses recent developments in the mechanical recycling of plastics, focusing on how to produce quality materials from waste streams and, thus, contribute to a sustainable management of resources and energy. [source]

Unmodified and Modified Surface Sisal Fibers as Reinforcement of Phenolic and Lignophenolic Matrices Composites: Thermal Analyses of Fibers and Composites

MACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2006
Jane Maria Faulstich de Paiva
Abstract Summary: The study and development of polymeric composite materials, especially using lignocellulosic fibers, have received increasing attention. This is interesting from the environmental and economical viewpoints as lignocellulosic fibers are obtained from renewable resources. This work aims to contribute to reduce the dependency on materials from nonrenewable sources, by utilizing natural fibers (sisal) as reinforcing agents and lignin (a polyphenolic macromolecule obtained from lignocellulosic materials) to partially substitute phenol in a phenol-formaldehyde resin. Besides, it was intended to evaluate how modifications applied on sisal fibers influence their properties and those of the composites reinforced with them, mainly thermal properties. Sisal fibers were modified by either (i) mercerization (NaOH 10%), (ii) esterification (succinic anhydride), or (iii) ionized air treatment (discharge current of 5 mA). Composites were made by mould compression, of various sisal fibers in combination with either phenol-formaldehyde or lignin-phenol-formaldehyde resins. Sisal fibers and composites were characterized by thermogravimetry (TG) and DSC to establish their thermal stability. Scanning electron microscopy (SEM) was used to investigate the morphology of unmodified and modified surface sisal fibers as well as the fractured composites surface. Dynamic mechanical thermoanalysis (DMTA) was used to examine the influence of temperature on the composite mechanical properties. The results obtained for sisal fiber-reinforced phenolic and lignophenolic composites showed that the use of lignin as a partial substitute of phenol in phenolic resins in applications different from the traditional ones, as for instance in other than adhesives is feasible. Micrograph of the impact fracture surface of phenolic composite reinforced with mercerized sisal fiber (500 X). [source]

WEAK AND STRONG SUSTAINABILITY, ENVIRONMENTAL CONSERVATION AND ECONOMIC GROWTH

NATURAL RESOURCE MODELING, Issue 3 2006
WERNER HEDIGER
ABSTRACT. To investigate the role of explicit and implicit assumptions in different models of weak and strong sustain-ability, the Solow/Hartwick model of intergenerational equity with nonrenewable resources is gradually extended to include renewable resources, endogenous technical progress, and stock pollution. This reveals the fundamental role of endogenous technical progress for sustainable development, the inconsistency of implicit sustainability assumptions in various models, as well as the existence of a Hartwick rule for Daly's steady-state economy. Moreover, it shows that the concepts of Solow sustainability and strong sustainability coincide as a special case of weak sustainability. The latter integrates economic and environmental concerns and aims at maintaining the welfare potential of an economy over time. It does not rule out economic growth by assumption. Rather, the analysis shows that environmental conservation and economic growth can be compatible with each other, without jeopardizing social welfare. Finally, the analysis shows that the discussion of sustain-ability models cannot be restricted to the explicit differences that are usually pointed out by their authors and commentators. Rather, implicit assumptions must be made explicit. [source]

Optimality of greedy and sustainable policies in the management of renewable resources

OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 1 2003
A. Rapaport
Abstract We consider a discrete-time modelling of renewable resources, which regenerate after a delay once harvested. We study the qualitative behaviour of harvesting policies, which are optimal with respect to a discounted utility function over infinite horizon. Using Bellman's equation, we derive analytically conditions under which two types of policies (greedy and sustainable) are optimal, depending on the discount rate and the marginal utility. For this particular class of problems, we show also that the greedy policy is attractive in a certain sense. The techniques of proof lie on concavity, comparison of value functions and Lyapunov-like functions. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Biorefinery systems , potential contributors to sustainable innovation

BIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 3 2010
Maria Wellisch
Abstract Sustainable biorefineries have a critical role to play in our common future. The need to provide more goods using renewable resources, combined with advances in science and technology, has provided a receptive environment for biorefinery systems development. Biorefineries offer the promise of using fewer non-renewable resources, reducing CO2 emissions, creating new employment, and spurring innovation using clean and efficient technologies. Lessons are being learned from the establishment of first-generation biofuel operations. The factors that are key to answering the question of biorefinery sustainability include: the type of feedstock, the conversion technologies and their respective conversion and energy efficiencies, the types of products (including coproducts) that are manufactured, and what products are substituted by the bioproducts. The BIOPOL review of eight existing biorefineries indicates that new efficient biorefineries can revitalize existing industries and promote regional development, especially in the R&D area. Establishment can be facilitated if existing facilities are used, if there is at least one product which is immediately marketable, and if supportive policies are in place. Economic, environmental, and social dimensions need to be evaluated in an integrated sustainability assessment. Sustainability principles, criteria, and indicators are emerging for bioenergy, biofuels, and bioproducts. Practical assessment methodologies, including data systems, are critical for both sustainable design and to assure consumers, investors, and governments that they are doing the ,right thing' by purchasing a certain bioproduct. If designed using lifecycle thinking, biorefineries can be profitable, socially responsible, and produce goods with less environmental impact than conventional products , and potentially even be restorative!. Copyright © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd [source]

Poplar as a feedstock for biofuels: A review of compositional characteristics

BIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 2 2010
Poulomi Sannigrahi
Abstract The growing demand for transportation fuels, along with concerns about the harmful effects of greenhouse gas emissions from the burning of fossil fuels, has assured a viable future for the development of alternative fuels from renewable resources, such as lignocellulosic biomass. The efficient utilization of these biomass resources is critically dependant on the in-depth knowledge of their chemical constituents. This, together with the desired fuel properties, helps tailor the chemical and/or enzymatic processes involved in converting biomass to biofuels. Hybrid poplars are among the fastest growing temperate trees in the world and a very promising feedstock for biofuels and other value-added products. Sequencing of the poplar genome has paved the way for tailoring new cultivars and clones optimized for biofuels production. Our objective is to review published research on the composition of the key chemical constituents of hybrid poplar species used for biofuels. Biomass yields, elemental composition, carbohydrate and lignin content and composition are some of the characteristics reviewed, with emphasis on lignin structure. Genetic modifications used to alter lignin content and composition, with the aim of improving biofuels yields, are also examined. Copyright © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd [source]

Metabolic engineering of Escherichia coli for the production of putrescine: A four carbon diamine

BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2009
Zhi-Gang Qian
Abstract A four carbon linear chain diamine, putrescine (1,4-diaminobutane), is an important platform chemical having a wide range of applications in chemical industry. Biotechnological production of putrescine from renewable feedstock is a promising alternative to the chemical synthesis that originates from non-renewable petroleum. Here we report development of a metabolically engineered strain of Escherichia coli that produces putrescine at high titer in glucose mineral salts medium. First, a base strain was constructed by inactivating the putrescine degradation and utilization pathways, and deleting the ornithine carbamoyltransferase chain I gene argI to make more precursors available for putrescine synthesis. Next, ornithine decarboxylase, which converts ornithine to putrescine, was amplified by a combination of plasmid-based and chromosome-based overexpression of the coding genes under the strong tac or trc promoter. Furthermore, the ornithine biosynthetic genes (argC-E) were overexpressed from the trc promoter, which replaced the native promoter in the genome, to increase the ornithine pool. Finally, strain performance was further improved by the deletion of the stress responsive RNA polymerase sigma factor RpoS, a well-known global transcription regulator that controls the expression of ca. 10% of the E. coli genes. The final engineered E. coli strain was able to produce 1.68,g,L,1 of putrescine with a yield of 0.168,g,g,1 glucose. Furthermore, high cell density cultivation allowed production of 24.2,g,L,1 of putrescine with a productivity of 0.75,g,L,1,h,1. The strategy reported here should be useful for the bio-based production of putrescine from renewable resources, and also for the development of strains capable of producing other diamines, which are important as nitrogen-containing platform chemicals. Biotechnol. Bioeng. 2009; 104: 651,662 © 2009 Wiley Periodicals, Inc. [source]

Use of Renewable Raw Materials in the Chemical Industry , Beyond Sugar and Starch

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2008
K. Muffler
Abstract Classical energy sources such as petroleum oil and natural gas make up the fundamental materials on which modern industrial chemical parks are based. According to the finite availability of these consuetudinary resources and due to the increasing demand for energy from developing countries and the related rise in prices of oil and natural gas, renewable resources must be considered as valuable alternatives. Discussions about climate change with regard to alternatives in energy production are preceded very fervidly but alternatives have to be examined from a matter-of-fact based economic and scientific point of view. Therefore, this review is focussed on alternative sources such as wood and other agricultural residues with respect to their potential as future energy resources as well as building blocks for chemical synthesis processes. [source]

Myrcene as a Natural Base Chemical in Sustainable Chemistry: A Critical Review

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 12 2009
Arno Behr Prof.
Abstract Currently, a shift towards chemical products derived from renewable, biological feedstocks is observed more and more. However, substantial differences with traditional feedstocks, such as their "hyperfunctionalization," ethical problems caused by competition with foods, and problems with a constant qualitative/quantitative availability of the natural products, occasionally complicate the large-scale market entry of renewable resources. In this context the vast family of terpenes is often not taken into consideration, although the terpenes have been known for hundreds of years as components of essential oils obtained from leaves, flowers, and fruits of many plants. The simple acyclic monoterpenes, particularly the industrially available myrcene, provide a classical chemistry similar to unsaturated hydrocarbons already known from oil and gas. Hence, this Review is aimed at reviving myrcene as a renewable compound suitable for sustainable chemistry in the area of fine chemicals. The versatility of the unsaturated C10 -hydrocarbon myrcene, leading to products with several different areas of application, is pointed out. [source]

The Renewable Chemicals Industry

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 4 2008
Claus Hviid Christensen Prof.
Abstract The possibilities for establishing a renewable chemicals industry featuring renewable resources as the dominant feedstock rather than fossil resources are discussed in this Concept. Such use of biomass can potentially be interesting from both an economical and ecological perspective. Simple and educational tools are introduced to allow initial estimates of which chemical processes could be viable. Specifically, fossil and renewables value chains are used to indicate where renewable feedstocks can be optimally valorized. Additionally, C,factors are introduced that specify the amount of CO2 produced per kilogram of desired product to illustrate in which processes the use of renewable resources lead to the most substantial reduction of CO2 emissions. The steps towards a renewable chemicals industry will most likely involve intimate integration of biocatalytic and conventional catalytic processes to arrive at cost-competitive and environmentally friendly processes. [source]