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The performance of nano-scale energy conversion devices is studied in the framework of state-space models where a device is described by a graph comprising states and transitions between them represented by nodes and links, respectively. Particular segments of this network represent input (driving) and output processes whose properly chosen flux ratio provides the energy conversion efficiency. Simple cyclical graphs yield Carnot efficiency for the maximum conversion yield. We give general proof that opening a link that separate between the two driving segments always leads to reduced efficiency. We illustrate these general result with simple models of a thermoelectric nanodevice and an organic photovoltaic cell. In the latter an intersecting link of the above type corresponds to non-radiative carriers recombination and the reduced maximum efficiency is manifested as a smaller open-circuit voltage. [ABSTRACT FROM AUTHOR]

Copyright of Annual Set the Environment Protection / Rocznik Ochrona Środowiska is the property of Koszalin University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Graphical abstract Highlights • Integration of biomass and solar energy in micro-hybrid systems is analysed. • Transcritical Organic Rankine Cycles at full and part-load are adopted. • Electric- and thermal-driven strategies are compared considering actual energy loads. • Hybrid systems are compared with full solar and full biomass power units. • Hybridisation guarantees high system efficiency and operating hours. Abstract The purpose of the work is to analyse the performance of an innovative fully renewable micro-hybrid energy system for combined heat and power generation. The apparatus is based on a transcritical Organic Rankine Cycle unit, fuelled by a conventional biomass boiler and a concentrated solar power system consisting of parabolic trough collectors. A thermodynamic model has been developed and the proper plant configurations have been defined through a parametric analysis. The possible application to the residential sector has been investigated considering typical domestic users in Southern Italy. The performance of the innovative micro combined heat and power system has been compared with the corresponding single-source systems (solar-only and biomass-only units). The investigation demonstrates that biomass/solar hybridisation allows reducing the biomass consumption, increasing the maximum operating hours, and improving the global system efficiency. Furthermore, the biomass integration raises the annual net solar-to-electric efficiency. In fact, hybridisation enables a better exploitation of the lowest solar radiations that are not sufficient to drive a full-solar Organic Rankine Cycle and to overcome the intermittency of the solar source. [ABSTRACT FROM AUTHOR]

Highlights • A model was developed to evaluate management options under future climate scenarios. • Management systems were evaluated in terms of their nutrient costs. • Nutrient outputs, ecosystem N-P balances, and changes in soil C-N-P were simulated. • Removing harvest residues and reducing rotation length have high nutrient costs. • Climate also has an impact, mainly through an effect of elevated atmospheric CO2. Abstract Intensifying the use of forest biomass to produce fuelwood, through the removal of harvest residues or reductions in rotation length, increases nutrient outputs and can ultimately lead to reduced soil fertility. We developed a modelling approach for the evaluation of different forest management options under future climate scenarios. This approach allows management systems to be evaluated in terms of their nutrient costs by quantifying several variables: nutrient outputs (N, P, K, Ca and Mg) resulting from harvesting, ecosystem N and P balances, and changes in organic C, N and P stocks in the soil. In addition, we calculated a “nutrient cost index” (in kg-harvested-biomass g-exported-nutrients−1). As part of this study, we looked at the effects of harvesting branches, foliage and stumps in addition to tree stems, as well as the effects of changing rotation length in Pinus pinaster , Pseudotsuga menziesii and Fagus sylvatica forest stands, under contrasting Representative Concentration Pathway climate scenarios (RCPs). Comparably to previous studies, our simulations showed that removing harvest residues and, to a lesser extent, reducing rotation length have high nutrient costs. Climate was also found to have an impact, mainly caused by larger amounts of standing tree biomass, and therefore larger biomass harvests and increased nutrient outputs in the scenario which involved elevated atmospheric CO 2. Using contrasting forest management systems and climates, we showed that our modelling approach can be used to guide forest managers in their choice of future silvicultural practices (rotation length, conventional stem-only harvest versus intensive harvest, thinning regime) based on future climate scenarios. Finally, our approach can be used to determine, more accurately than simple allometric relationships, the amounts of nutrients that would need to be applied in order to compensate for losses. [ABSTRACT FROM AUTHOR]

Due to the growing number of small biomass boilers in residential buildings, the ash amounts from these plants are increasing. In order to find a beneficial use for these ashes, chemical and physical analyses were carried out on different ash fractions of different boilers. The results enable a comparison of the used boilers and fuels. As a result, it was shown that the chemical composition and physical properties strongly depend on the type of the ash, the fuel, and the boiler. The main focus of the investigations was on assessing whether the ashes were to be classified as fertilizer or waste. Accordingly, the results of the analyses were compared with the respective limit values for these cases. In addition, further possible applications were evaluated with regard to their suitability, and related current problems were identified. Chemical and physical analyses were carried out on different ash fractions of diverse small biomass boilers, enabling a comparison of the boilers and fuels used. Chemical composition and physical properties were shown to strongly depend on the type of the ash, the fuel, and the boiler. The investigations focused on assessing whether the ashes can be classified as fertilizer and not as waste. [ABSTRACT FROM AUTHOR]

In this study, a novel low cost and sustainable microalgal harvesting technique was developed using the concept of coagulant recovery concentration and recycling. Al 3+ can be recovered from harvested Scenedesmus acuminatus biomass with 0.1 M HCl, at an acid solution-biomass ratio of 250 ml g −1 . The residual Al 3+ content in the purified biomass was reduced to 0.11 ± 0.0006 mg g −1 , while a higher content of 59.74 ± 3.11 mg g −1 was found in the coagulation harvested biomass. The recovered Al 3+ solution was concentrated 25 times and then reused for the harvesting of S. acuminatus . The Al 3+ recovery and reuse were repeated 5 times, and the harvesting efficiencies were found higher than the fresh Al 3+ as a result of the presence of extracellular polymeric substances in the recovered coagulant solution which aided the coagulation process. According to the technical-economic analysis, the cost of chemicals decreased 50% after 5 times recycling. [ABSTRACT FROM AUTHOR]

Woody crops such as orchards and olive groves require annual pruning operations, which leave abundant residues on the ground. These must be removed both for disease control and for facilitating the following tending activities. The resulting biomass can be managed as a waste or a by-product, in both cases incurring in a cost for farmers. A harvester prototype for collecting and comminuting apple pruning residues was tested and compared to a traditional mulcher. In particular, the study aimed at: 1) quantifying productivity and costs of the two systems, 2) evaluating the possible influence of apple variety, tree age and machine type on the productivity per hectare, and 3) estimating and comparing the energy balance of the two working options. The mulcher achieved a productivity of 0.41 ha SMH −1 against an average 0.27 ha SMH −1 of the harvester. Age of trees significantly influenced the productivity of both machines, with operative speed 42% higher in younger plantations. The cost of the operation added up to 137.5 € ha −1 and 275.2 € ha −1 , respectively for the mulcher and the harvester. But the latter also produced 0.77 t dry matter ha −1 of biomass fuel suitable for in-farm use, whose value can cover most or the total of harvest costs. Accordingly, the energetic inputs amounted to 0.59 GJ ha −1 and 1.06 GJ ha −1 respectively for the mulcher and the harvester, while the recovered biomass provided an output of 6.30 GJ ha −1 for the latter system, resulting in a positive energy ratio (5:1). [ABSTRACT FROM AUTHOR]

In order to understand the climate effects of a bioenergy system, a comparison between the bioenergy system and a reference system is required. The reference system describes the situation that occurs in the absence of the bioenergy system with respect to the use of land, energy, and materials. The importance of reference systems is discussed in the literature but guidance on choosing suitable reference systems for assessing climate effects of bioenergy is limited. The reference system should align with the purpose of the study. Transparency of reference system assumptions is essential for proper interpretation of bioenergy assessments. This paper presents guidance for selecting suitable reference systems. Particular attention is given to choosing the land reference. If the goal is to study the climate effects of bioenergy as a part of total anthropogenic activity the reference system should illustrate what is expected in the absence of human activities. In such a case the suitable land reference is natural regeneration, and energy or material reference systems are not relevant. If the goal is to assess the effect of a change in bioenergy use, the reference system should incorporate human activities. In this case suitable reference systems describe the most likely alternative uses of the land, energy and materials in the absence of the change in bioenergy use. The definition of the reference system is furthermore subject to the temporal scope of the study. In practice, selecting and characterizing reference systems will involve various choices and uncertainties which should be considered carefully. It can be instructive to consider how alternative reference systems influence the results and conclusions drawn from bioenergy assessments. [ABSTRACT FROM AUTHOR]

This study improves upon and applies a comprehensive panel data simultaneous equation model to the European Union (EU28) region's bioenergy market. The goals are to estimate bioenergy quantities in domestic and international markets for the period from 1990 to 2013 and to apply a forecasting analysis for the EU28's domestic and international bioenergy markets for the period of 2014–2020. The results demonstrate that biomass harvest and the domestic price in a domestic market have a significant influence on the supply function. Additionally, domestic price has a negative relationship with the bioenergy market domestic demand. In international markets, competitive import prices play a primary role in the development of the bioenergy market import demand. Export prices and GDP also have primary influences on the export demand for bioenergy. Moreover, the exchange rate has a positive and significant effect on export demand. The results of a forecasting analysis for the future period of 2014–2020 has predicted slight increases in domestic supply, domestic demand, and import trends. On the other hand, it also predicted a sharp decline in the export demand trend between those same years. This study contributes to the literature by providing policymakers and other energy policy stakeholders a reliable, forward-looking analysis of the potential condition of the domestic and international bioenergy markets in the EU28 region through the end of 2020. [ABSTRACT FROM AUTHOR]

Bioenergy sources have been introduced as a means to address challenges of conventional energy sources. The uncertainties of supply-side (upstream) externalities (e.g., collection and logistics) represent the key challenges in bioenergy supply chains and lead to reduce cross-cutting sustainability benefits. We propose a mixed biomass-based energy supply chain (consisting of mixed-mode bio-refineries and mixed-pathway transportation) and a multi-criteria decision making framework to address the upstream challenges. Our developed framework supports decisions influencing the economic and environmental dimensions of sustainability. Economic analysis employs a support vector machine technique, to predict the pattern of uncertainty parameters, and a stochastic optimization model, to incorporate uncertainties into the model. The stochastic model minimizes the total annual cost of the proposed mixed supply chain network by using a genetic algorithm. Environmental impact analysis employs life cycle assessment to evaluate the global warming potential of the cost-effective supply chain network. Our presented approach is capable of enhancing sustainability benefits of bioenergy industry infrastructure. A case study for the Pacific Northwest is used to demonstrate the application of the methodology and to verify the models. The results indicate that mixed supply chains can improve sustainability performance over traditional supply infrastructures by reducing costs (up to 24%) and environmental impacts (up to 5%). [ABSTRACT FROM AUTHOR]

Hybrid poplar is a woody crop grown for the production of bioenergy, biofuels and bioproducts. Harvesting is often the largest single cost in the production system and the development and optimization of equipment is evolving. The objective of this study was to evaluate the performance of a single-pass, cut-and-chip harvesting operation in commercial plantings that included four cultivars, two spacing treatments, and two coppice planting designs (dedicated, and interplanted with sawtimber). Approximately 15 h of harvesting using a New Holland 9080 forage harvester equipped with a purpose-built coppice header was monitored over four days. Stand biomass ranged between 34 and 78 Mg ha −1 of fresh biomass and effective material capacity (C m ) of the harvester ranged from 10 to 78 Mg h −1 of fresh biomass excluding headland activities. Tree spacing had a significant effect on C m but cultivar and planting design did not. The treatments did not have discernible effects on machine fuel consumption (mean 83 L h −1 ; ơ 16.4) or crop-specific fuel consumption for fresh biomass (mean 1.34 L Mg −1 ; ơ 0.31). Crop-specific fuel consumption was positively correlated with engine load, and negatively correlated with standing biomass; this result was statistically significant but negligible (<1%) in terms of liters of fuel used for each additional Mg ha −1 of stand biomass for engine loads ranging between 30% and 110%. [ABSTRACT FROM AUTHOR]

Copyright of Misr Journal of Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A decision making method is developed, to evaluate bioenergy technologies towards a sustainable bioenergy system. The multi criteria method is based on a transparent framework with direct computation on the hesitant fuzzy linguistic data, incorporating experts’ preferences trying to deal with the incompleteness and inconsistency of the information of bioenergy technologies in different sustainability dimensions. In this context, globally existing bioenergy technologies are identified and then prioritized against fifteen different criteria relevant to environmental, economic, technological and social aspects of sustainability. It is distinguished that production of biogas, heat and electricity from agricultural, municipal and industrial wastes achieves higher overall performance compared to the other technologies in Iran. This technology contributes to rural development and job creation in less developed areas of country. Also, it does not threaten food security and does not have effect on land use change or biodiversity loss. [ABSTRACT FROM AUTHOR]

Combustion in a biomass-fired boiler causes build-up of soot, which reduces the heat transfer and decreases the efficiency of operation. In order to mitigate this natural occurrence, cleaning via soot blowing is an important maintenance action. The objective of this study is to develop long-term optimal maintenance strategies, which are model-based and specifically employ the dynamics of boiler efficiency and of anticipated heating demand, both of which are identified from empirical data. An approximate dynamic programming algorithm is set up, resulting in the optimal maintenance actions over time, so that the total operational costs of the biomass boiler plus the cleaning costs are minimized. A practical case study with real data is used to elucidate the benefits of the new approach. [ABSTRACT FROM AUTHOR]

Due to the stochastic behavior of the wind speed, accessing the wind energy would be problematic in some critical moments. One feasible solution lies in the use of wind turbines to produce hydrogen through an electrolyzer and by using wind-hydrogen hybrid systems. However, many of the issues related to these systems should be investigated to make landmark decisions about their performance. For instance, there is a lack of study on the reliability assessment of the wind-hydrogen systems; for this purpose, the main objective of this study is to evaluate the reliability of a stand-alone wind-hydrogen energy conversion system unconnected to the grid. The proposed system consists of two major parts: the rectifier and the buck converter. The primary task of the rectifier is to rectify the wind turbine output voltage to a constant DC voltage. Additionally, the buck converter is responsible to reduce the voltage level to a 48 V voltage, which meets the voltage requirement of the 3.6 kW electrolyzer. The results of the performed simulations showed that the rectifier is under more thermal stresses than the buck converter. The predicted mean time to failure (MTTF) of the hybrid system is approximately 7.6 years, and this estimation can affect the maintenance and refurbishment costs. [ABSTRACT FROM AUTHOR]

An artificial microalgal-bacterial consortium was used to remediate a mixture of analgesics (ketoprofen, paracetamol and aspirin) in a stirred-tank photobioreactor. A hydraulic retention time (HRT) of 3 days supported poor treatment because of the formation of p -aminophenol (paracetamol toxic metabolite). Increasing the HRT to 4 days enhanced the bioremediation efficiency. After applying an acclimatization regime, 95% removal of the analgesics mixture, p -aminophenol and COD reduction were achieved. However, shortening the HRT again to 3 days neither improved the COD reduction nor ketoprofen removal. Applying continuous illumination achieved the best analgesics removal results. The harvested biomass contained 50% protein, which included almost all essential amino acids. The detected fatty acid profile suggested the harvested biomass to be a good biodiesel-producing candidate. The water-extractable fraction possessed the highest phenolic content and antioxidant capacity. These findings suggest the whole process to be an integrated eco-friendly and cost-efficient strategy for remediating pharmaceutical wastewater. [ABSTRACT FROM AUTHOR]

Constructing a commercial biorefinery involves significant financial and technical risks that may affect investor willingness to commit funds. Repurposing existing industrial facilities has been proposed as a means to lessen the investment risk in constructing a new biorefinery through reduced financial requirements and startup costs. This research provides a decision-making tool for estimating the repurpose potential of existing industrial facilities considered for conversion to a biorefinery. It applies well-established techniques for capital cost estimation of Greenfield biorefinery and pulp mill infrastructure and assets to determine their repurpose potential as a biorefinery. It demonstrates how capital cost reduction is highly dependent on the process technology present in the subject facility. A factored approach is employed to assign valuation to the major capital cost components of a Greenfield biorefinery. Existing facilities are then assessed for their compatibility through an infrastructure and asset analysis to determine an estimated capital percent savings that may be realized through repurposing into a biorefinery. Private and public databases and general facility process designs are used to determine the presence of equipment in each facility assessed. A yes/no analysis is performed to assign full cost to facility infrastructure and assets not present in the biorefinery and no cost to those that are present. This methodology provides an economic valuation tool for facility assessments as a metric for facility comparisons, and may be used to assist in decision-making regarding the suitability of a facility for repurposing. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

The paper substantiates the mechanical and technological principles of formalizing the structure of agroecosystems on the basis of optimizing the interdependence between the elements of the agroecosystem within a specified range of conditions. The equipment for the production of bioenergy resources is improved by means of minimizing its energy capacity with all qualitative indices of the technological processes preserved. [ABSTRACT FROM AUTHOR]

The paper presents a mathematical model of power-engineering complex implementing a combined technology of production of power, heat, and solid biofuels, namely, torrefied pellets. Torrefaction of fuel pellets is carried out in a thermochemical reactor by heat from exhaust gases of a gas piston power plant. The results of testing the model by experimental data and the results of calculations of the main characteristics of torrefaction, the mass and energy flows are given. The analysis results of efficiency of the power plant with a build-on thermochemical reactor are reported. [ABSTRACT FROM AUTHOR]

The long-term (> 10 years) oxidation behaviour of stainless steels (SS) at high temperatures was previously unknown. The behaviour was studied through a case study of failure analysis. A fluidisation nozzle made of 304 austenitic SS. After over 100,000 h of service at temperatures of 790–820 °C in a biomass boiler, the nozzle fractured. Failure analysis pinpoints that the nozzle wall temperature fluctuation caused the oxide scale cracking, which intensified the oxidation. The brittle fracture was due to fully oxidization. The long-term oxidation behaviours are distinct from the short-term oxidation behaviours. XRD analysis indicates that the scale was mainly Fe + 2 Cr 2 O 4 and (Fe 0.6 Cr 0.4 ) 2 O 3 . ESEM/EDS analysis indicates internal oxidation and sulfidation along the grain boundaries. The different diffusion rates of the Fe, Cr and Ni atoms formed a Ni-rich (48%) layer underneath the scale, and a Cr-rich (35%) core in the remained SS. A schematic is proposed to describe the diffusion mechanism of the internal oxidization and sulfidation behaviour. [ABSTRACT FROM AUTHOR]

Munksøgård is a housing community near the city of Roskilde, Denmark. In 2014, Munksøgård's residents have agreed to change the existing heat supply system. The choice of future heat supply was narrowed to heat pumps, new biomass boilers and connection to nearby district heating network. The choice was additionally narrowed as a result of the voting at the general assembly. The present paper presents results from techno-economic energy system analysis, simple private-economic analysis and assessment of externalities related to the heat supply, compares them with the voting results and discusses the differences. The potential inconsistencies between economically rational solutions and choices of end-users are highlighted. The techno-economic energy system analysis is performed by TIMES-DK model, which optimizes over all sectors in Denmark until 2050. The connection to district heating proved to be optimal from the system perspective. A spreadsheet model has been developed to perform the private-economic analysis and the evaluation of externalities. New biomass boilers proved to be the cheapest from the private-economic perspective; district heating came close. At the voting, heat pumps and biomass boilers received the most votes. One of these two solutions will be implemented. Why district heating received the least votes calls for detailed investigation. [ABSTRACT FROM AUTHOR]

In the present work, microalgae strains, such as Scenedesmus obliquus and Phaeodactylum tricornutum grown in indoor/outdoor photobioreactors (PBRs) and in open ponds (this is the first study on such strains cultivated in the local Southern Italy climatic conditions), were fully analyzed for their protein content, carbohydrates, lipids, and fatty acid profile in order to assess their potential use for the production of biofuels, chemicals, and omega-3, and as animal feed and human food. They are compared with Nannochloropsis sp. (commercial sample) which was fully analyzed in our laboratory and Chlorella (literature data). An economic evaluation was carried out, demonstrating that the cultivation of microalgae for the production of only biofuels will not match the economic standards. Conversely, if chemicals are also produced applying the biorefinery concept and using wastewater as a source of nutrients, it will be possible to have a good positive return from microalgae. [ABSTRACT FROM AUTHOR]

While woody bioenergy opens up a new market opportunity for residual biomass, overharvesting of residual biomass can adversely affect soil health, water quality, timber health and stand productivity, among others. As such, it is important to understand the proportion of residual biomass forestland owners are willing to leave unharvested for soil nutrient and other environmental benefit purposes, their sustainability concerns, and policy preferences. Toward this end, we conducted a mail survey on 900 randomly selected forestland owners in Virginia and used ordinal logistic regression, cluster analyses, and Cochran-Armitage trend tests to analyze the data. Our analyses of the 121 most complete responses suggest that factors such as ownership tenure, mode of land acquisition, size of forestland, and forestland ownership objectives, among other factors, affect decisions regarding the proportion of residual biomass forestland owners choose to leave unharvested. Analyses of landowners' sustainability concerns indicate a clustering pattern, where concerns about sufficiency of best management practices and the potential implications of harvest decision on soil and water quality are among the statistical representatives of their respective clusters. Respondents likely to engage in harvest practices that do not leave any residual biomass on the ground have a preference for policies that help cover management cost. Decision makers administering or considering such policy proposals should be aware of the inadvertent effect such cost sharing arrangements can have in encouraging unsustainable practices. These results also hint at the potential need for combining such cost sharing arrangements with extension and outreach programs. By accounting for landowners' concerns and preferences, this study complements previous studies that primarily adopt engineering based approaches and solutions. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis is a microorganism that allows the biosynthesis of δ-endotoxins with toxic properties against some insect larvae, being often used for the production of biological insecticides. A key issue for the bioprocess design consists in adequately tracking a pre-specified optimal profile of the dissolved oxygen concentration. To this effect, this paper aims at developing a novel control law based on a nonlinear dynamic inversion method. The closed-loop strategy includes an observer based on a Bayesian Regression with Gaussian Process, which is used for on-line estimating the biomass present in the bioreactor. Unlike other approaches, the proposed controller leads to an improved response time with effective disturbance rejection properties, while simultaneously prevents undesired oscillations of the dissolved oxygen concentration. Simulation results based on available experimental data were used to show the effectiveness of the proposal. [ABSTRACT FROM AUTHOR]

Technological solutions to reduce greenhouse gas (GHG) emissions from anthropogenic sources are required. Heavy industrial processes, such as steel making, contribute considerably to GHG emissions. Fermentation of carbon monoxide (CO)-rich off gases with wild-type acetogenic bacteria can be used to produce ethanol, acetate, and 2,3-butanediol, thereby, reducing the carbon footprint of heavy industries. Here, the processes for the production of ethanol from CO-rich off gases are discussed and a perspective on further routes towards an integrated biorefinery at a steel mill is given. Recent achievements in genetic engineering as well as integration of other biotechnology platforms to increase the product portfolio are summarized. Already, yields have been increased and the portfolio of products broadened. To develop a commercially viable process, however, the extraction from dilute product streams is a critical step and alternatives to distillation are discussed. Finally, another critical step is waste(water) treatment with the possibility to recover resources. [ABSTRACT FROM AUTHOR]

This review lays the foundation for why nutrient recovery must be a key consideration in design and operation of biorefineries and comprehensively reviews technologies that can be used to recover an array of nitrogen, phosphorus, and/or potassium-rich products of relevance to agricultural applications. Recovery of these products using combinations of physical, chemical, and biological operations will promote sustainability at biorefineries by converting low-value biomass (particularly waste material) into a portfolio of higher-value products. These products can include a natural partnering of traditional biorefinery outputs such as biofuels and chemicals together with nutrient-rich fertilizers. Nutrient recovery not only adds an additional marketable biorefinery product, but also avoids the negative consequences of eutrophication, and helps to close anthropogenic nutrient cycles, thereby providing an alternative to current unsustainable approaches to fertilizer production, which are energy-intensive and reliant on nonrenewable natural resource extraction. [ABSTRACT FROM AUTHOR]

We investigated the long-term impact of biomass utilization on shrub recovery, species composition, and biodiversity 38 years after harvesting at Coram Experimental Forest in northwestern Montana. Three levels of biomass removal intensity (high, medium, and low) treatments combined with prescribed burning treatment were nested within three regeneration harvest treatments (shelterwood, group selection, and clearcut). Four shrub biomass surveys (pre-treatment, 2, 10, and 38 years after treatment) were conducted. Shrub biomass for all treatment units 38 years after treatment exceeded the pre-treatment level, and biomass utilization intensity did not affect shrub recovery (ratio of dry biomass at time t to pre-treatment biomass). Species composition changed immediately after harvesting (2 years); however, the species composition of treated units did not differ from the untreated control 38 years after harvesting. Biodiversity indices (Shannon’s and Pielou’s indices) also decreased immediately following harvesting, but recovered 10 years after harvesting. The responses of diversity indices over time differed among biomass utilization levels with the high-utilization level and unburned treatment producing the most even and diverse species assemblages 38 years after harvesting. Our results indicate the shrub community is quite resilient to biomass harvesting in this forest type. [ABSTRACT FROM AUTHOR]

The effect of viscosity reduction caused by the solubilization of CO 2 is studied in order to improve the biomass processing in ionic liquids. To do so, densities and viscosities of the pure ionic liquid 1-allyl-3-methylimidazolium chloride and its mixtures with CO 2 up molar fractions of 0.25 and temperatures between 333 and 372 K have been experimentally determined. Viscosities were correlated as a function of temperature and CO 2 molar fractions with an average relative error of 2.5%. The viscosities of other mixtures CO 2 + ionic liquids were also correlated for other ionic liquids with an average relative error between 4.4 and 13%. In general these ionic liquids present a linear decrease of viscosity with CO 2 molar fractions up to around 0.5 that is more pronounced at lower temperatures and depends of each ionic liquid, and can reach between 60 and 100% viscosity reduction with respect the viscosity of the pure ionic liquid, making the CO 2 a promising co-solvent for viscosity reduction in process with ionic liquids. [ABSTRACT FROM AUTHOR]

While current biorefinery processes use lignin only for its heat value, the conversion of lignin to high value chemicals is an area of increasing interest. Herein we present a detailed mechanistic study of the hydrodeoxygenation (HDO) of lignin by using a synergistic Pd/C and ZnII catalyst through use of both lignin model compounds and lignocellulosic biomass. Spectroscopic data coupled with the study of lignin model compounds suggest that ZnII activates and facilitates removal of the hydroxyl group at the Cγ position of the β-O-4 ether linkage. Activation is proposed to occur through formation of a six-membered ring complex of ZnII coordinated to the oxygen atoms at Cα and Cγ of the lignin model compound guaiacylglycerol-β-guaiacyl. [ABSTRACT FROM AUTHOR]

This paper presents a novel piezoelectric energy harvester, which is a MEMS-based device. This piezoelectric energy harvester uses a bifurcate-shape. The derivation of the mathematical modeling is based on the Euler-Bernoulli beam theory, and the main mechanical and electrical parameters of this energy harvester are analyzed and simulated. The experiment result shows that the maximum output voltage can achieve 3.3V under an acceleration of 1g at 292.11Hz of frequency, and the output power can be up to 0.155mW under the load of 0.4MΩ. The power density is calculated as 496.79µWmm-3. Besides that, it is demonstrated efficiently at output power and voltage and adaptively in practical vibration circumstance. This energy harvester could be used for low-power electronic devices. [ABSTRACT FROM AUTHOR]

Logging residues are often utilized as a Best Management Practice (BMP) for stabilizing bare soil on forest harvesting operations. As utilization of woody biomass increases, concern has developed regarding availability of residues for implementing BMPs. The Virginia Department of Forestry (VDOF) inspects all logging operations in Virginia and randomly selects a portion of harvests for more intensive audits. The VDOF BMP audit process intensively evaluates implementation of BMPs in seven categories (84 specific BMPs) on 240 sites per year. This research analyzed three years of audit data (2010–2012) to quantify differences in BMP implementation between biomass and conventional harvesting operations. Among 720 audited tracts, 97 were biomass harvests, with 88 occurring in the Piedmont region. Only the streamside management zone (SMZ) category had significant implementation percentage differences between biomass (83.1%) and conventional harvests (91.4%) (p = 0.0007) in the Piedmont. Specific areas where biomass harvesting operations had lower implementation were generally not related to a lack of residues available for implementing BMPs, but rather were from a lack of appropriate SMZs, overharvesting within SMZs, or inadequate construction of roads, skid trails, and stream crossings. Existing BMP recommendations already address these areas and better implementation would have negated these issues. [ABSTRACT FROM AUTHOR]

Foresters often require an estimation of bark thickness from a reference height (typically breast height) to accurately estimate the bark or wood volume of a tree. Various models for estimating the bark thickness of interior Douglas-fir (Pseudotsuga menziesii var. glauca) from measured dbh (diameter at breast height) were evaluated. Sample trees were from northern Rocky Mountain mixed conifer stands that had been subjected to four levels of experimental woody biomass harvesting. Among simple linear, nonlinear, and segmented linear mixed effects models, the segmented linear model performed best. A join point (where the linear equations are linked) for the segmentation was statistically detected at approximately 19.0 cm dbh. The join point seems to indicate the size at which juvenile Douglas-fir trees boost the production of bark tissue, perhaps as those trees express dominance over competing understory vegetation. Woody biomass utilization level had no impact on bark thickness, indicating that the bark:dbh relationship does not depend on biomass utilization intensity. The study results enable accurate bark thickness estimation for interior Douglas-fir in this region, and suggest several silvicultural applications for juvenile Douglas-fir stand management. [ABSTRACT FROM AUTHOR]

The integration of renewable biomass feedstocks is receiving primal attention in energy and process industries. The conversion of biomass is typically faced with multiple options with respect to feedstocks, processing paths and product portfolios. The options for sustainable bio-based material have been highlighted in Association for the Advances of Industrial Crops Network (AAIC), that promotes the processing of crops towards industrial products. The systematic screening of these options is a major challenge. The paper presents a decision support environment that is capable of rapidly evaluating, screening and integrating biomass processing paths to bio-energy and other renewable products. The environment has built and makes use of an information repository that integrates data from various sources. A modelling environment enables the formulation and techno-economic and environmental assessments of both individual and integrated paths. The analysis involves optimization models for the high-throughput evaluation of options reporting recommendations and integrated paths when appropriate, as well as co-products more prominent to select. The proposed approach has been implemented into a software prototype and tested by industrial users, with the possibility to be extended and used by the wider community in the future. The prototyped modelling environment is outlined and illustrated by several case studies. [ABSTRACT FROM AUTHOR]

Burning feedstock with high and constantly varying moisture content is a challenge in the operation of the stoker-grate type biomass boilers in pulp and paper mills. A fundamental study was performed, using a thermogravimetric combustor controlled at different temperatures, to systematically investigate the effect of moisture content on the combustion behavior of several woody biomasses. The results show that combustion occurred through three stages: drying, devolatilization, and char burning. Increasing the moisture content of the sample above 30% significantly increased the drying time and the time to ignition of the sample. Moisture content, however, had only a small effect on the devolatilization rate and virtually no effect on the char burning rate. Furnace temperature had a great effect on combustion. Samples containing 40% moisture could still ignite and burn readily at 800°C, but they took a much longer time to ignite at 500°C and did not ignite at 400°C. These results imply that in biomass boiler operation, the high moisture content in feedstock delays combustion and causes the furnace temperature to decrease. The low temperature, in turn, suppresses combustion, further decreasing the furnace temperature and causing more delay in combustion. This downward spiral will eventually lead to a boiler blackout unless the biomass feed rate is significantly reduced or the auxiliary fuel (natural gas and fuel oil) flow rate cofired in the boiler is increased to keep the furnace temperature high. [ABSTRACT FROM AUTHOR]

Availability of cost-competitive biomass conversion technologies plays crucial role for successful realization of biorefinery for sustainable production of fuels and organic chemicals from biomass. The present article provides an outline of opportunities and socio-techno-economic challenges of various biomass processing technologies. The biomass processing technologies were classified into three broad categories: thermochemical, chemical and biochemical. This review article presents an overview of two potential thermochemical conversion processes, gasification and fast pyrolysis, for direct conversion of lignocellulosic biomass. The article further provides a brief review of chemical conversion of triglycerides by transesterification with methanol for production of biodiesel. The highly productive microalgae as an abundant source of triglycerides for biodiesel and various other fuels products were also reviewed. The present article also provides an outline of various steps involved in biochemical conversion of carbohydrates to alcoholic bio-fuels, bio-ethanol and bio-butanols and conversion of nature׳s most abundant aromatic polymer, lignin, to value-added fuels and chemicals. Furthermore, an overview of production of hydrocarbon fuels through various biomass processing technologies such as hydrodeoxygenation of triglycerides, biosynthetic pathways and aqueous phase catalysis in hydrocarbon biorefinery were highlighted. The present article additionally provides economic comparisons of various biomass conversion technologies. [ABSTRACT FROM AUTHOR]

While there are some large and fundamental differences among disciplines related to the conversion of biomass to bioenergy, all scientific endeavors involve the use of biological feedstocks. As such, nearly every scientific experiment conducted in this area, regardless of the specific discipline, is subject to random variation, some of which is unpredictable and unidentifiable (i.e., pure random variation such as variation among plots in an experiment, individuals within a plot, or laboratory samples within an experimental unit) while some is predictable and identifiable (repeatable variation, such as spatial or temporal patterns within an experimental field, a glasshouse or growth chamber, or among laboratory containers). Identifying the scale and sources of this variation relative to the specific hypotheses of interest is a critical component of designing good experiments that generate meaningful and believable hypothesis tests and inference statements. Many bioenergy feedstock experiments are replicated at an incorrect scale, typically by sampling feedstocks to estimate laboratory error or by completely ignoring the errors associated with growing feedstocks in an agricultural area at a field or farmland (micro- or macro-region) scale. As such, actual random errors inherent in experimental materials are frequently underestimated, with unrealistically low standard errors of statistical parameters (e.g., means), leading to improper inferences. The examples and guidelines set forth in this paper and many of the references cited are intended to form the general policy and guidelines for replication of bioenergy feedstock experiments to be published in BioEnergy Research. [ABSTRACT FROM AUTHOR]

The performance of coppice harvesting machines is influenced by parameters such as field yield, the shape and size of the plantation and the space for turning at the headland. The quality of chips and the effect of the dendrometric characteristic of nine different species ( Fraxinus angustifolia, Robinia pseudoacacia, Salix alba, Eucalyptus occidentalis, Populus nigra L. and four genotypes of Populus x euroamericana (Grimminge, Hoogvorst, Muur, Vesten) grown in the same flat plot of about 4.5 ha on the performance rate and quality of the work, was evaluated. Field yields ranged from 33 t ha −1 to ∼95 t ha −1 , for the S. alba and E. occidentalis, respectively. The harvester worked with an average speed of 0.91 m s −1 (±0.22) and average productivities of 0.98 ha h −1 (±0.24) and 45.25 t h −1 (±5.56). There was a satisfactory linear correlation between the working speed of the machine and field yield. The quality of the chips showed some variability with values of moisture content ranging between 42.7% and 57.3% (for R . pseudoacacia and S. Alba respectively) and values of bulk density from 273 kg m −3 to 313 kg m −3 (for Populus euroamericana Vesten and E . occidentalis respectively). [ABSTRACT FROM AUTHOR]

Bioenergy is a new source of energy that accounts for a substantial portion of the renewable energy production in many countries. The production of bioenergy is expected to increase due to its unique advantages, such as no harmful emissions and abundance. Supply-related problems are the main obstacles precluding the increase of use of biomass (which is bulky and has low energy density) to produce bioenergy. To overcome this challenge, large-scale optimization models are needed to be solved to enable decision makers to plan, design, and manage bioenergy supply chains. Therefore, the use of effective optimization approaches is of great importance. The traditional mathematical methods (such as linear, integer, and mixed-integer programming) frequently fail to find optimal solutions for non-convex and/or large-scale models whereas metaheuristics are efficient approaches for finding near-optimal solutions that use less computational resources. This paper presents a comprehensive review by studying and analyzing the application of metaheuristics to solve bioenergy supply chain models as well as the exclusive challenges of the mathematical problems applied in the bioenergy supply chain field. The reviewed metaheuristics include: (1) population approaches, such as ant colony optimization (ACO), the genetic algorithm (GA), particle swarm optimization (PSO), and bee colony algorithm (BCA); and (2) trajectory approaches, such as the tabu search (TS) and simulated annealing (SA). Based on the outcomes of this literature review, the integrated design and planning of bioenergy supply chains problem has been solved primarily by implementing the GA. The production process optimization was addressed primarily by using both the GA and PSO. The supply chain network design problem was treated by utilizing the GA and ACO. The truck and task scheduling problem was solved using the SA and the TS, where the trajectory-based methods proved to outperform the population-based methods. [ABSTRACT FROM AUTHOR]

This paper discusses how to develop and manage integration, coordination and cooperation in bio-energy supply chains. Farmers decisions on whether or not to participate in a contract farming scheme have been investigated, particularly assessing the trade-offs between the contract attributes and their impact on the likelihood to participate. A stated preference model was implemented where respondents were asked to choose between alternative contracts with varying attribute levels to start biomass cultivation. Results show that participation is mainly influenced by minimum price guaranteed, contract length, and re-negotiation before the end of a contract. [ABSTRACT FROM AUTHOR]

Butanol has recently gained increasing interest due to escalating prices in petroleum fuels and concerns on the energy crisis. However, the butanol production cost with conventional acetone-butanol-ethanol fermentation by Clostridium spp. was higher than that of petrochemical processes due to the low butanol titer, yield, and productivity in bioprocesses. In particular, a low butanol titer usually leads to an extremely high recovery cost. Conventional biobutanol recovery by distillation is an energy-intensive process, which has largely restricted the economic production of biobutanol. This article thus reviews the latest studies on butanol recovery techniques including gas stripping, liquid-liquid extraction, adsorption, and membrane-based techniques, which can be used for in situ recovery of inhibitory products to enhance butanol production. The productivity of the fermentation system is improved efficiently using the in situ recovery technology; however, the recovered butanol titer remains low due to the limitations from each one of these recovery technologies, especially when the feed butanol concentration is lower than 1 % ( w/v). Therefore, several innovative multi-stage hybrid processes have been proposed and are discussed in this review. These hybrid processes including two-stage gas stripping and multi-stage pervaporation have high butanol selectivity, considerably higher energy and production efficiency, and should outperform the conventional processes using single separation step or method. The development of these new integrated processes will give a momentum for the sustainable production of industrial biobutanol. [ABSTRACT FROM AUTHOR]

In pyrolysis of biomass process: solid, liquid and gas products are obtained. To optimize the organic material degradation, a variety of catalysts are employed. Morphological changes in the catalysts during the pyrolysis reaction are evaluated by Transmission Electron Microscopy (TEM) technique. In this work, a pore and pore wall sizes, before and after pyrolysis process, of a Cu/SBA-15 catalysts are characterized. From results it is observed that the catalyst not present morphological changes in the pyrolysis of biomass, indicating the possible re-use of catalyst in similar succesive processes. [ABSTRACT FROM AUTHOR]

Bioenergy development can offer beneficial ecological and economic synergies through the expansion of eco-logical restoration projects. Such synergies are demonstrated by means of a case study conducted in central Washington State, where a 52.4-ha ecological restoration site on the Yakama Reservation generated 34 mega-grams (Mg) of invasive tree biomass per hectare, costing $988 ha"1. A geospatial model of transportation costs estimated that extracted invasive tree biomass can generate revenues throughout 1103 803 ha when delivered to a proposed bioenergy facility in White Swan, Washington, providing 53 000-180000 Mg of biomass per year for several decades. Thermochemical analyses revealed that the elevated nitrogen, sulfur, and ash con-tent in two prolific invasive trees - Russian olive (Elaeagnus angustifolia) and salt cedar (Tamarix spp) - will limit demand for either of these invasive species. We compare our regional data to national estimates, and show the broader potential for expanding ecological restoration activities and biomass supplies through the revenues generated by the sale of invasive tree wood-waste into bioenergy markets. [ABSTRACT FROM AUTHOR]

Bioethanol production from lignocellulose biomass is becoming of increasing importance because of its low-cost, widely available, non-food competence and high sugar content. However, lignocellulose is more difficult to convert than sugars, starches and oils because it consists of a complex mixture of cellulose, hemicellulose and lignin. To break down its complex structure, a pretreatment step is required. For that purpose physical, physico-chemical, chemical, biological or a combination of pretreatment steps have been proposed to process the raw materials [23]. Pretreatment is essential for the economic success of the entire system because the pretreatment may represent up to one-third of the overall processing cost [14]. The impact of the pretreatment step on the overall process motivates the development of models suitable for process design and optimization. This study presents the modelling and optimization of the pretreatment of sugarcane bagasse for bioethanol production. Alternative pretreatment steps are considered, including dilute-acid hydrolysis (with different acids) and processing with liquid hot water. Models for each pretreatment step are derived from experimental data from the literature, based on an understanding of the kinetics involved in the different reactions and incorporating the kinetics into mass balances models to quantify the consumption and generation of the different components. The models are implemented in the Jacaranda system for process design and optimisation [8] to identify the optimal process conditions for each pretreatment. Results show the interaction between design variables (i.e. residence time, operating temperature or acid concentration) and optimal conditions. [ABSTRACT FROM AUTHOR]