Characteristics of some firewood trees and shrubs of the North Eastern Himalayan region, India

An evaluation of the characteristics of 25 indigenous trees and shrubs of the North Eastern Himalayan (NEH) region was carried out to identify trees with potential for firewood production. A fuelwood value index (FVI) was defined as the calorific value×density/ash content. The results showed that Gaultheria fragrantissima, Litsea citrata, Myrica esculenta, Aesculus assamica, Daphniphyllum himalense, Mesua ferrea, and Wendlandia tinctoria had the most promising firewood properties.     

Energy potential of native shrub species in northern Spain

This paper we present an energy review of the waste generated by shrub species in soils of low fertility for use as fuel in a power plant. The residues analysed belong to the species: Rhamus alaternus, Ulex europaeus, Prunus spinosa, Smilax aspera, Erica sp., Rubus ulmifolius, and Pteridium aquilinum. Gross calorific value (GCV), net calorific value (NCV), density, elementary chemical analysis, moisture content, percentage of ash, productivity, energy density and FVI (fuel value index) have been measured. These parameters have been determined for three levels of moisture (maximum, medium and minimum). At medium moisture level, the residues of U. europaeus are those that reach the greatest FVI, 20,000. In the other extreme is the P. aquilinum with an FVI of 403. The average productivity of waste, in t ha⁻¹, of each species has been determined in order to know how much energy is stored per hectare. U. europaeus and P. spinosa are the species which accumulate more energy per hectare, with similar values of around 81 MJ ha⁻¹ yr⁻¹ and installed power of 2.59 W ha⁻¹. The energy recovery of the waste in a thermal power plant would generate an annual revenue of 14.6 M€, taking into account that 40% of the forest land covered by shrub in Cantabria is used for this purpose.     

Fuelwood consumption pattern at different altitudes in rural areas of Garhwal Himalaya

The use of fuelwood as a primary source of energy for domestic use is causing severe deforestation in Garhwal Himalaya. In the present study fuelwood consumption patterns have been studied in six villages; two each in tropical (Ganga Bhogpur and Kunow), sub-tropical (Bhainswara and Ghargoan) and temperate (Dhaulana and Chunnikhal) regions under various ecological and socio-economic conditions. The total average fuelwood consumption in the present study was observed to be highest for Ganga Bhogpur (2.52 kg per capita per day) in the tropical region, whereas, lowest for Ghargoan (1.63 kg per capita per day) in the sub-tropical region. The labour energy expenditure for fuelwood collection was greatest for Dhaulana (146.62 MJ per capita per day) in the temperate region, and lowest for Ganga Bhogpur (88.80 MJ per capita per day) in the tropical region. The fuelwood consumption rate oscillated considerably across the different seasons. The tree and shrub species preferred by the inhabitants for fuelwood were Holoptelea integrifolia, Anogeissus latifolia and Lantana camara in the tropical region; A. latifolia, Acacia catechu and Carissa spinarum in the sub-tropical region; and Quercus leucotrichophora, Myrica esculenta and Pyracantha crenulata in the temperate region, respectively.     

Comparative study of fuelwood consumption by villagers and seasonal “Dhaba owners” in the tourist affected regions of Garhwal Himalaya,India

The rural inhabitants of the Himalayan region have been exploiting forest resources for their livelihood for generations. The excessive and uncontrolled use of firewood for domestic purposes has ended up with severe deforestation. Therefore, quantification, assessment and restoration of such valuable but exhaustible resources and is imperative their scientific management. The estimates reflect that a total of 88 species are consumed as fuelwood (54 trees and 34 shrubs) by the local people. Fuelwood consumption by ‘dhaba’ (roadside refreshment establishments) owners (90–120 kg/household/day) was much higher over the common villagers (20–22 kg/household/day). The fuelwood is mainly burnt for cooking, water heating, space heating and lighting, etc. Among these, cooking consumes the fuelwood most. In addition, fuelwood demand increases due to influx of tourists. In the near future, this may also affect the status of the undisturbed forests at the middle elevation. The information in this communication could be utilized for developing various conservation and sustainable strategies in the region to mitigate the impact of forest resource for fodder and fuelwood.     

Preference and calorific value of fuelwood species in rural populations in northwestern Patagonia

Traditional knowledge of fuel species was evaluated, associating species preferences with the physical properties of wood and its combustibility. The physical characteristics of 21 popular firewood species were analyzed in three rural communities in the northwest of Patagonia. Semi-structured interviews were carried out in 91 homes, as well as free listing and walks; samples of the woody species were collected in each of the homes visited. We have hypothesized that the experience of gathering and using fuelwood species, as cognitive know-how, over generations will have enabled local people to know species have best fuel attributes, such as hot coals, low spark and low smoke emission. Thus, for each sample, calorific value, density, moisture content and ash content were measured as predictive variables of combustibility. The fuel attributes of the different woods represent physical properties for which were analyzed by means of the classification for Fuel Value Index (FVI) priority species in the area. Results indicate that the species with the highest FVI values are those mostly preferred by local people such as Berberis microphylla, Prosopis denudans, Schinus johnstonii, Lycium spp., Senecio subulatus and Schinus marchandii. This work recommends the cultivation of energy crops of the preferred native species with high combustibility, to be used as bioenergy and multipurpose species.     

An evaluation of South African fuelwood with regards to calorific value and environmental impact

The fuelwood commonly used in the Western Cape of South Africa, namely Acacia cyclops (Rooikrans), Acacia erioloba (Camelthorn), Eucalyptus cladocalyx (Blue gum), Pinus patula (South African pine) and Vitis vinifera (Vine stumps), was evaluated with regards to its calorific value and environmental impact when burned. Properties, such as density, ash content and elemental composition were determined and related to the calorific value. It could be demonstrated that the wood with the highest calorific value does not necessarily constitute the best option as fuelwood, if environmental factors are taken into account.     

Utilization pattern of fuelwood plants by the Halam community of Tripura,Northeast India

The present study was undertaken to identify the fuelwood plant species and their utilization pattern by the Halam community of Tripura. The main objective of this study was to assess the species preference as fuelwood, the total value index, and the fuelwood value index (FVI) of 22 species. The majority of the households use the plant resources for domestic purpose. Although the community’s mostly preferred fuelwood species were Tectona grandis L.f, Shorea robusta C. F. Gaertn, and Gmelina arborea Roxb, a total of 22 species were reported from the study site. Trewia nudiflora L., Albizia procera Benth., Dysoxylum procerum Hierm., and Cassia siamea Lam. were also reported as fuelwood species with good wood quality (FVI). Thus awareness on the use of these species as fuelwood can be increased in the community to reduce stress on the preferred species and the surrounding forest.     

Calorific value of Prosopis africana and Balanites aegyptiaca wood: Relationships with tree growth, wood density and rainfall gradients in the West African Sahel

Prosopis africana and Balanites aegyptiaca are native tree species in the West African Sahel and provide wood for fuel, construction and other essential products. A provenance/progeny test of each species was established at one relatively dry site in Niger, and evaluated at 13 years. Gross calorific value of the wood was determined for a random sample of trees in each test: gross CV and CVm³ = gross calorific value in MJ kg⁻¹ and MJ m⁻³, respectively. The major objectives were to determine if gross CV was positively correlated with wood density and tree growth, and if gross CV and/or CVm³ varied with rainfall gradients in the sample region. Provenances were grouped into a drier and more humid zone, and correlations were computed among all trees and separately in each zone. Results indicated that gross CV was not significantly correlated with density in either species. Gross CV was positively correlated with growth of P. africana (but not B. aegyptiaca) only in the drier zone. Gross CVm³ was positively correlated with growth of both species, and the correlations were stronger in the drier zone. Multiple regressions with provenance latitude, longitude and elevation indicated that provenance means for gross CV increased, in general, from the drier to the more humid zones. Regressions with gross CVm³ were not significant. Results are compared with earlier research reports from the provenance/progeny tests and with other tropical hardwood species; and practical implications are presented for tree improvement and conservation programs in the region.     

Fuelwood characteristics of indigenous tree species of north-east India

Fuelwood characteristics viz. moisture content, ash, silica, carbon, nitrogen, volatile matter, density and calorific value of 35 indigenous tree species of the age group of 10–15 years growing in their natural habitat in north-eastern region of India were determined and Fuel Value Index (FVI) of each of them was calculated. From the experimental data and the FVIs, it is found that Acacia nilotica, Acacia auriculiformis, Albizzia lebbeck, Albizzia procera, Pinus kesiya and Elaeognus umbellata possess better fuelwood characteristics and they may be considered for inclusion in energy plantation programme in the region.     

Evaluation of short-rotation coppicing fuelwood production systems for Papua New Guinea

A 2 year short-rotation coppicing (SRC) fuelwood production system was evaluated, at 2 tree densities (3333 and 6666 trees ha⁻¹) for the Western Highlands Province (WHP) and National Capital District (NCD) of Papua New Guinea. Of the 10 species tested, the best production of firewood was from Eucalyptus grandis and Eucalyptus robusta in WHP and Eucalyptus tereticornis in the NCD, with values of 2.97 m³, 2.55 m³, and 0.92 m³ for a 500 m² woodlot respectively at the denser spacing. E. grandis and E. robusta produced best tree form in WHP while Eucalyptus pellita produced best form in NCD. Best coppice performance was observed in E. robusta in WHP and E. tereticornis in NCD. The burning characteristics of SRC firewood and charcoal were also assessed, as well as how SRC firewood will appeal to consumers. In the highlands SRC firewood and charcoal yield higher estimated returns to labour (USD20.00 and USD11.16 person⁻¹day⁻¹) compared with main alternative crops of sweet potato and coffee (USD9.77 and USD6.98 person⁻¹day⁻¹ respectively). SRC pole production has a low return to labour (USD7.44 person⁻¹day⁻¹) but could complement SRC production as part of a thinning regime. The main limitation in promulgating SRC systems could be market acceptance and finding a small-business model that integrates well with the indigenous non-market economy. The poor growth rates around the NCD due to limiting biophysical conditions make a 2 year rotation cycle unfeasible.     

Characterization of microalgal species isolated from fresh water bodies as a potential source for biodiesel production

Due to increasing oil prices and climate change concerns, biodiesel has gained attention as an alternative energy source. Biodiesel derived from microalgae is a potentially renewable and carbon–neutral alternative to petroleum fuels. One of the most important decisions in obtaining oil from microalgae is the choice of algal species to use. Eight microalgae from a total of 33 isolated cultures were selected based on their morphology and ease of cultivation. Five cultures were isolated from river and identified as strains of Scenedesmus obliquus YSR01, Nitzschia cf. pusilla YSR02, Chlorella ellipsoidea YSR03, S. obliquus YSR04, and S. obliquus YSR05, and three were isolated from wastewater and identified as S. obliquus YSW06, Micractinium pusillum YSW07, and Ourococcus multisporus YSW08, based on LSU rDNA (D1-D2) and ITS sequence analyses. S. obliquus YSR01 reached a growth rate of 1.68 ± 0.28 day⁻¹ at 680_nm and a biomass concentration of 1.57 ± 0.67 g dwt L⁻¹, with a high lipid content of 58 ± 1.5%. Under similar environmental conditions, M. pusillum reached a growth rate of 2.3 ± 0.55 day⁻¹ and a biomass concentration of 2.28 ± 0.16 g dwt L⁻¹, with a relatively low lipid content of 24 ± 0.5% w/w. The fatty acid compositions of the studied species were mainly myristic, palmitic, palmitoleic, oleic, linoleic, g-linolenic, and linolenic acids. Our results suggest that S. obliquus YSR01 can be a possible candidate species for producing oils for biodiesel, based on its high lipid and oleic acid contents.     

Rural energy and fuel forests in China

The structure of rural energy consumption for living (domestic) in China is presented based on the nationwide survey conducted from 1986 to 1987. The fuelwood energy consumed amounted to 29% of the totally consumed living energy. The average deficit of fuelwood supply was about 25% for the whole country. The reasonable exploitation of fuelwood resource was 265 Mm³, while the actual fuelwood consumption was 355 Mm³. A fuelwood demand of 443 Mm³ by 2000 was predicted based on a model. Another 4.2 Mha of fuel forests need to be established. The main problems existing in the management and utilization of fuel forests in China are analyzed, and some recommendations are presented.     

An experimental investigation of electro-osmotic drag coefficients in a polymer electrolyte membrane fuel cell

Through the use of a water balance experiment, the electro-osmotic drag coefficients of Nafion 115 were obtained under several conditions (as a function of water content and thermodynamics conditions). For the cases when the anode was fully hydrated (corresponding to water content λ ≈ 14 in the adjacent membrane) and the cathode suffered from drying when dry air was supplied (λ ≈ 2), the electro-osmotic drag coefficients varied from 0.82 (±0.06) to 0.50 (±0.03) H₂O/H⁺ when the current density varied from 0.4 to 1.0 A cm⁻² (95% confidence level). When the current density increased, the electro-osmotic drag coefficient decreased. When the water content at the anode increased from λ ≈ 5 to λ ≈ 14, the cathode was supplied with dry air (λ ≈ 2), and the fuel cell discharged constant current density at 0.6 A cm⁻², the electro-osmotic drag coefficient increased from 0.44 (±0.06) to 0.68 (±0.06) H₂O/H⁺ (95% confidence level). Higher relative humidity gas leads to a higher electro-osmotic drag coefficient at constant current density.     

Preparation and characterization of Ppy/Al2O3/Al used as solid-state capacitors for microsystems—Effect of amount of electricity passed

This investigation focuses on the preparation of polypyrrole composite films, Ppy/Al₂O₃/Al, used as solid-state capacitor with electrochemical polymerization in the presence of DBSA, co-dopant and co-solvent. The parameters of the solid-state capacitor, i.e. leakage current (Lc), capacitor (Cs), dicipation factor (DF) and equivalent series resistance (ESR), were measured in this study. The surface morphology and compositions of the prepared Ppy/Al₂O₃/Al electrolyte were examined using SEM and EDS, respectively. Further, for 3 C of electricity passed, the values of Lc, Cs, DF and ESR of the Ppy/Al₂O₃/Al capacitor prepared with 2-NSNa and DBSA as a co-dopant were measured to be 0.029 ± 0.005 μA cm⁻², 688.8 ± 8.28 nF cm⁻², 14.35 ± 5.63% and 18.63 ± 3.48 Ω. Further, the parameters both of R_ox and R_ppy are 135.5 and 7.047 Ω.     

A property rights-based analysis of the illegal logging for fuelwood in Kosovo

The increased demand for fuelwood may have the side-effect of unsustainable use of forest resource. The case of Kosovo fuelwood production is of a peculiar relevance to studying the drivers of the unsustainable patterns of forest biomass use in a post-war and poor economic context. The domestic market demand for fuelwood in Kosovo is estimated at more than 1.5 hm³, while the legal supply, including imports, is slightly higher than 0.3 hm³. Illegal logging for satisfying Kosovo population fuelwood needs is therefore widespread. The annual illegal fuelwood harvesting represents a market of up to 21.6 million euro and is done mostly by well organised groups of individuals, with market-oriented behaviour, acting rather in State than in private forests. After identifying the drivers of illegal logging for fuelwood, the paper provides an analysis of fuelwood extraction in relation with property rights distribution, structured along two lines: a) which was the evolution of the management and exclusion rights over the forest resource during the latest decades; b) which are the current enforcement mechanisms of the property rights and how are they performing. The paper describes a decades-long history of mismatching economic property rights arrangements. Thus, the dispute between the central agency and municipalities in performing exclusion rights on timber extraction definitely weakened the Kosovo system of law enforcement. Currently, the enforcement mechanism proved to be unhelpful in controlling illegal logging. As result, most of the Kosovo fuelwood production is based on an de facto open-access regime.     

Energy value as a factor of agroforestry wood species selectivity in Akinyele and Ido local government areas of Oyo State, Nigeria

Wood usage for cooking and heating is still very relevant in most developing countries especially those of sub-Saharan Africa and many parts of Asia. Therefore, sustainable means of generating it for this and other purposes are necessary bearing in mind the influence of indigenous knowledge/users' perspective on any production method regarding success and sustenance. In conformity with this view, questionnaires were administered on 240 respondents in 8 rural communities of Akinyele and Ido Local Government Areas (LGAs) of Oyo State, Nigeria, to elicit information on species that can be used as fuelwood, preferred by the respondents for incorporation into and/or retention in agroforestry plots, out of which 179 (i.e. 75% of the total number of questionnaires administered) were successfully retrieved for statistical analyses. Twelve woody species namely: Annona senegalensis, Anogeissus leiocarpus, Bridelia ferruginea, Daniellia oliveri, Detarium microcarpum, Gardenia ternifolia, Hymenocardia acida, Lophira lanceolata, Parkia biglobosa, Terminalia avicennioides, Triplochiton scleroxylon and Vitellaria paradoxa were prioritized on the basis of respondents' preference using a ranking pattern. Friedman chi-square analysis showed that there was no significant difference (p < 0.05) in the ranking pattern of the respondents from the two LGAs. The mean net calorific values (NCV) of the 12 species were found to be 17.71, 18.63, 18.04, 16.03, 17.67, 18.46, 19.00, 21.68, 19.63, 18.25, 14.65, and 19.47 MJ kg⁻¹ respectively. The result of a two-way analysis of variance indicated a significant variation (p < 0.05) in NCV data for all the species pooled together but not for each species except for D. oliveri with a follow-up test using Fisher's Least Significant Difference. The Pearson's moment correlation analysis gave positive coefficient values (r = 0.868 and 0.874, p < 0.05) between NCV and the cumulative ranking values in Akinyele and Ido LGAs respectively. There was also a coefficient value of 0.873 (p < 0.05) between the cumulative ranking values in the two LGAs. In line with the outcome of this study, it was therefore recommended that native intelligence/indigenous knowledge and/or users' perspective should be part of the criteria for selecting potential fuelwood species for incorporation into and/or retention in agroforestry systems in this and other areas with similar characteristics.     

Cloning and knockout of formate hydrogen lyase and H2-uptake hydrogenase genes in Enterobacter aerogenes for enhanced hydrogen production

A 5431-bp DNA fragment partially encoding the formate hydrogen lyase (FHL) gene cluster hycABCDE was isolated and identified from Enterobacter aerogenes IAM1183 chromosomal DNA. All the five putative gene products showed a high degree of homology to the reported bacterial FHL proteins. The gene hycA, encoding the FHL repressor protein, and hybO, encoding the small subunit of the uptake hydrogenase, were targeted for genetic knockout for improving the hydrogen production. The pYM-Red recombination system was adopted to form insertional mutations in the E. aerogenes genome, thereby creating mutant strains of IAM1183-A (△hycA), IAM1183-O (△hybO), and IAM1183-AO (△hycA/△hybO double knockout). The hydrogen production experiments with these mutants showed that the maximum specific hydrogen productivities of IAM1183-A, IAM1183-O, and IAM1183-AO were 2879.466 ± 38.59, 2747.203 ± 13.25 and 3372.019 ± 4.39 (ml h⁻¹ g⁻¹dry cell weight), respectively, higher than that of the wild strain (2321.861 ± 15.34 ml h⁻¹ g⁻¹dry cell weight). The total H₂ yields by the three mutants IAM1183-A, IAM1183-O and IAM1183-AO were 0.73, 0.78, and 0.83 mol-H₂/mol glucose, respectively, while the wild-type IAM1183 was only 0.65 mol-H₂/mol glucose. The metabolites of the mutants including acetate, ethanol, 2,3-butanediol and succinate were all increased compared with that of the wild type, implying the changed metabolic flux by the mutation. In the fermentor cultivation with IAM1183△hycA/△hybO, the total hydrogen volume after 16 h cultivation reached 4.4 L, while that for the wild type was only 2.9 L.     

Investigation of the combined effects of acetate and photobioreactor illuminated fraction in the induction of anoxia for hydrogen production by Chlamydomonas reinhardtii

In the context of hydrogen production by microalgae, the growth of Chlamydomonas reinhardtii was characterized under autotrophic and mixotrophic conditions in a fully controlled photobioreactor (PBR). The combined effect of light transfer conditions, as represented by the illuminated fraction γ, with acetate consumption was observed upon establishment of anoxia. Anoxia was reached in batch cultures when γ was close to 1 (almost fully illuminated culture) in mixotrophic conditions while a value of γ ≈ 0.46 in autotrophic conditions was not sufficient. Based on these results, continuous hydrogen production was established in a cylindrical PBR operated in luminostat with constant illumination and in mixotrophic conditions. Maximum hydrogen gas production was equal to 1.4 ± 0.1 ml_H2 l⁻¹ h⁻¹ for photon flux density of 110 μmol m⁻² s⁻¹ and reactor illuminated fraction of γ = 0.5. Carbon mass balance was realized, emphasizing the necessity to work in strictly autotrophic conditions for hydrogen production with no concomitant CO₂ release.     

Efficiency enhancement of polymer solar cells by incorporating a self-assembled layer of silver nanodisks

We report the efficiency enhancement of polymer solar cells by incorporating a silver nanodisks' self-assembled layer, which was grown on the indium tin oxide (ITO) surface by the electrostatic interaction between the silver particles and modified ITO. Polymer solar cells with a structure of ITO (with silver nanodisks)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) (Clevious P VP AI 4083)/poly(3-hexylthiophene):[6,6]-phenyl-C61 butyric acid methyl ester (P3HT:PC₆₁BM)/LiF/Al exhibited an open circuit voltage (V_OC) of 0.61±0.01 V, short-circuit current density (J_SC) of 9.24±0.09 mA/cm², a fill factor (FF) of 0.60±0.01, and power conversion efficiency (PCE) of 3.46±0.07% under one sun of simulated air mass 1.5 global (AM1.5G) irradiation (100 mW/cm²). The PCE was increased from 2.72±0.08% of the devices without silver nanodisks to 3.46±0.07%, mainly from the improved photocurrent density as a result of the excited localized surface plasmon resonance (LSPR) induced by the silver nanodisks.     

Improved performance of microbial fuel cell using combination biocathode of graphite fiber brush and graphite granules

The efficiency and sustainability of microbial fuel cell (MFC) are heavily dependent on the cathode performance. We show here that the use of graphite fiber brush (GBF) together with graphite granules (GGs) as a basal material for biocathode (MFC reactor type R1) significantly improve the performance of a MFC compared with MFCs using GGs (MFC reactor type R2) or GFB (MFC reactor type R3) individually. Compared with R3, the use of the combination biocathode (R1) can shorten the start-up time by 53.75%, improve coulombic efficiencies (CEs) by 21.0 ± 2.7% at external resistance (R_EX) of 500 Ω, and increase maximum power densities by 38.2 ± 12.6%. Though the start-up time and open circuit voltage (OCV) of the reactor R2 are similar to R1, the CE (R_EX = 500 Ω) and maximum power density of R2 are 21.4 ± 1.7% and 38.2 ± 15.6% lower than that of R1. Fluorescence in situ hybridization (FISH) analyses indicate the bacteria on cathodes of R1 and R2 are richer than that of R3. Molecular taxonomic analyses reveal that the biofilm formed on the biocathode surface is dominated by strains belonging to Nitrobacter, Achromobacter, Acinetobacter, and Bacteroidetes. Combination of GFB and GGs as biocathode material in MFC is more efficient and can achieve sustainable electricity recovery from organic substances, which substantially increases the viability and sustainability of MFCs.