A harvest and transport cost model for Eucalyptus spp. fast-growing short rotation plantations

This project developed a cost model for the mechanical harvesting of fast-growing Eucalyptus plantations. With such a model, forest managers can check the profitability of a prospective operation under different work conditions and assess the competitiveness of alternative options, which in turn will lead to supply chain optimization. The model is based on mathematical relationships that return machine productivity as a function of operational conditions. These relationships were calculated on data obtained from detailed time studies, conducted on all the main equipment types used in Eucalyptus plantations. Tests were conducted on 11 different machines that harvested a total 2465 oven-dry tonnes over 23 ha on 12 sites in 3 countries. The time study sessions lasted 250 h. Both the Cut-to-Length (CTL) system and the Whole-Tree (WT) system were studied. The model was validated with success and was used to make a number of different simulations. Simulation results show that the WT system allows cheaper harvesting and transport than the CTL system for a range of conditions. Under the conditions of our simulations and in favourable terrain, WT harvesting results in a delivered cost of about 20 euro/green tonne of bark-free pulp chips, whereas CTL harvesting results in a cost between 25 and over 30 euro/green tonne of debarked pulp roundwood.     

A study on the combustibility of torrefied wood oil/water mixture droplets

This paper presents the results of an experimental study on the combustion characteristics of torrefied wood (TW) slurries using suspended droplets. The main factors that were investigated in this study are the initial diameter of the slurry droplets, the ambient temperature, the composition of the slurries including the solid content and the percentage content of a second liquid added to the parent slurry. The results show a linear relationship between the square of the initial diameter of the droplet and total combustion time for all kinds of TW-based slurries that were studied here but the slope of the line depends on the composition of the slurries and the ambient temperature. Also, the combustibility of TW-based slurries was better than charcoal-based slurries due to the better combustibility of TW. By adding a certain amount of a second liquid, especially water, to a TW-oil mixture, the combustibility of the resulting slurry was improved.     

Investigation on the physical properties of the charcoal briquettes prepared from wood sawdust and cotton stalk

The physical properties of the charcoal briquettes prepared from biomass waste are usually poor. In the paper, an alternative approach to the charcoal briquette preparation from the densified biomass briquette by carbonization was addressed. The carbonization process of the biomass briquettes prepared from cotton stalk (CS), wood sawdust (WS) and their blends was performed in a fixed bed at 400~600°C. The variation in the mass and volume of the biomass briquettes before and after the carbonization process and the physical properties of the resulted charcoal briquettes were investigated. The results indicate that the physical properties of the charcoal briquettes including bulk density and compression strength decreased firstly and then increased as the temperature increased. CS charcoal briquettes with better physical properties showed more volume shrinkage than WS charcoal briquettes after the carbonization process. However, the physical properties of the charcoal briquettes from the blends were poorer than expected due to the co-pyrolysis characteristics of CS and WS.     

Effects of pH, glucose and iron sulfate concentration on the yield of biohydrogen by Clostridium butyricum EB6

A local bacterial isolate from palm oil mill effluent (POME) sludge, identified as Clostridium butyricum EB6, was used for biohydrogen production. Optimization of biohydrogen production was performed via statistical analysis, namely response surface methodology (RSM), with respect to pH, glucose and iron concentration. The results show that pH, glucose concentration and iron concentration significantly influenced the biohydrogen gas production individually, interactively and quadratically (P < 0.05). The center composite design (CCD) results indicated that pH 5.6, 15.7 g/L glucose and 0.39 g/L FeSO₄ were the optimal conditions for biohydrogen production, yielding 2.2 mol H₂/mol glucose. In confirmation of the experimental model, t-test results showed that curve fitted to the experimental data had a high confidence level, at 95% with t = 2.225. Based on the results of this study, optimization of the culture conditions for C. butyricum EB6 significantly increased the production of biohydrogen.     

Impact of genotype, harvest time and chemical composition on the methane yield of winter rye for biogas production

Rye (Secale cereale L.) is an ideal crop for the agricultural biogas production in regions with less fertile and sandy soils. Maximum methane yield per hectare is the main aim of the farmer. Objectives were to establish differences by the Hohenheim Biogas Test among (1) 25 genotypes (experiment 1) and (2) three harvest dates (early heading, early and late milk ripening) and three plant fractions (ears, leaves and stems, stubbles) for four genotypes including an analysis of their nutrient composition (experiment 2). Significant (P < 0.05) genotypic variation was found for dry matter yield, specific gas yield and methane yield among the 25 genotypes, but no differences for methane content and specific methane yield. Broad ranges were achieved for dry matter yield (0% water content) and methane yield amounting to 2.9 t ha⁻¹ and 840 m³ ha^-1 respectively, combined with moderate to high heritabilities (0.71-0.98). Both traits were highly correlated (r = 0.95, P < 0.01). Compared to population and forage rye, hybrid rye achieved significantly higher methane yields. The latest harvest date at late milk ripening resulted in the highest dry matter yield on a whole plant level with an average of 16.0 t ha⁻¹. Accordingly, methane yield was reaching a mean of 4424 m³ ha^-1 and a maximum of 4812 m³ ha^-1. No correlations between content of crude nutrients or cell-wall fractions and specific gas or methane yield were evident neither for the plant fractions nor for the whole plant. In conclusion, harvesting at late milk ripening was clearly superior in dry matter and methane yields although specific methane yield was higher at early heading. A selection for maximum dry matter yield in rye breeding should indirectly improve also methane yield.     

木屑纤维素酶水解条件的试验研究

采用正交试验法研究了稀盐酸预处理木屑的最优条件:反应温度为105℃,反应时间为3 h,用质量分数为2%的HCl预处理后,半纤维素质量分数降低了78.4%,木质素降低了29.3%.用纤维素酶水解预处理过的木屑,考察了pH值、温度、时间对酶水解率的影响,结果表明:酶解温度为50℃,pH值为4.8,纤维素酶液用量为2 ml/g,水解时间为48 h时,酶水解率达到76%,纤维素质量分数降低了65.4%.     

Prediction of boiling, scaling and formation conditions in geothermal reservoirs using computer programs tequil and geofluids

Predictions of boiling, scaling, and solubility of gases are important to the exploitation of geothermal resources. These chemical phenomena are strong functions of the composition, temperature and pressure of the working fluid and are therefore difficult to predict from prior experience or tabulated data. Thermodynamic models of geothermal brine behavior recently developed by the authors are introduced and used to study various problems involved in geothermal energy production. The models have been extensively tested. Results of comparisons with laboratory measurements indicate that predictions are very close to experimental data for a wide range of conditions. Comparisons with field data also show remarkable agreement. Here the models are also applied to the prediction of breakout and scale formation in geothermal wells. Good agreement is obtained with actual well performance.     

Effects of weak-alkali ASP composition on the stability of O/W emulsions

The effects of weak-alkali ASP composition on the o/w emulsion-stabilizing properties of simulative produced liquid by the weak-alkali ASP flooding were analyzed by use of spinning-drop interfacial-tension (IFT) meters, microscopes, zeta-potential analyzer and Turbiscan laboratory expert stabilizer in this work. The experimental results showed that the irregular movement of the droplets in the lower and middle regions is the main cause of the instability of the emulsion system. The addition of alkali changes the movement of emulsion droplets formed by the weak-alkali ASP system and the oil. Both weak-alkali and surfactants play dual roles in the ASP system. The optimum amount can make the emulsion achieve the best stability and less or more amounts are not conducive to the stability of the emulsion. Appropriately increasing the polymer concentration is helpful to increase the stability of the emulsion. However, the addition of an excessively high concentration of polymer does not increase the stability of the emulsion, resulting in unnecessary waste. It is expected that this study will be of guiding significance for the mechanism of weak-alkali ASP flooding and the treatment of produced liquid in actual production.     

Analysis of the impact of science and technology on energy R and D

A pilot study for Turkey, which analyzes the interrelationships of disciplines of science and technology with energy R and D activities, is described. Some preliminary results are given and further refinements of the approach are discussed.     

Design of chemical composition and optimum working conditions for trivalent black chromium electroplating bath used for solar thermal collectors

Black chromium is one of the selective surfaces which are commonly used in solar thermal systems. The aim of this research was to design an electroplating bath, using chromium trivalent ions instead of its hexavalent ions because of its toxicity, for black chromium coating to produce a good metallurgical and light properties at low cost and reproducibility. The effect of the additives was investigated and a coating with an absorption coefficient of 0.96 was prepared. The bath contained inexpensive constituents such as chromium sulfate, cobalt chloride, sodium fluoride, sodium hypophosphite and sodium dihydrogen phosphate and did not need any pH control. Thermal resistance, corrosion resistance and adhesion of the coatings as well as throwing power of the bath were investigated. The effect of bright Ni as an undercoat before black chromium electroplating was also investigated. SEM and XRD techniques were employed to characterize the surface microstructure and chemical composition. Spectroscopy was also used to measure absorptance of the coatings.     

Prediction of the yield of biohydrogen under scanty data conditions based on GM(1,N)

Biohydrogen technology is regarded as one of the most promising ways for hydrogen production with the considerations of economic priority and environmental performance. In this study, grey model is used to predict the yield of biohydrogen under scanty data condition. An illustrative case has been studied by the proposed method, and pH, glucose and iron sulfate concentration are used as the independent variables, the yield of biohydrogen is used as dependent variable in the grey prediction model, and 9 groups of data are used as the training samples and another 2 groups of data are used as the test samples, the results show that the proposed method is feasible to predict the yield of biohydrogen under scanty data condition and the effect of the influencing factors on the yield could also be identified. According to the comparison with the results predicted by artificial neural network, it could be concluded that grey model has better predictability with scanty data. This method could be popularized to other biohydrogen systems.     

Effects of flocculants on lipid extraction and fatty acid composition of the microalgae Nannochloropsis oculata and Thalassiosira weissflogii

The aim of this study was to investigate the possible interference of anionic and cationic flocculants in the lipid extraction and fatty acid profiles of two species of marine microalgae: Nannochloropsis oculata and Thalassiosira weissflogii. Cells were grown in batch cultures (f/2 medium, salinity of 28, temperature of 20 °C, light intensity of 40 ??mol photons  m^-2 s^-1 and 12/12 h L/D photoperiod) and concentrated using sodium hydroxide (control), sodium hydroxide and the anionic polyacrylamide flocculant Magnafloc^® LT-25 (APF treatment) and sodium hydroxide plus the cationic polyacrylamide flocculant Flopam^® (CPF treatment). There were no statistically significant differences among treatments with respect to lipid extraction for both species. However, N. oculata which presented higher percentages of C16:0, C16:1 and C20:5 fatty acids showed an increase of C14:0 and a decrease of C20:5 with the use of anionic flocculant. Additionally, T. weissflogii which had high percentages of C16:0, C16:1, C16:3 and C20:5, showed a decrease of C18:0 and C18:1n9c when both flocculants were used and a small decrease of C16:0 in the APF treatment. The results indicate that the choice of flocculant should be based on the level of saturation desirable, i.e., if the goal is to produce more stable biodiesel, with low percentage unsaturated fatty acids, then anionic flocculants should be used. On the other hand, if the aim is to produce unsaturated fatty acids for commercial uses in the pharmacy or food industries, then anionic polymers should be avoided.     

NaOH/H2O2预处理促进玉米秸秆酶解产糖工艺条件的研究

采用正交实验初步探讨了NaOH/HO2O2对经白腐菌Hyrophous sp.254处理15 d的玉米秸秆进行预处理的最佳条件.在NaOH/H2O2预处理过程中,NaOH浓度、H2O2体积分数、底物浓度及预处理时间均对秸秆的纤维素酶酶解效率存在一定影响.试验表明,NaOH/H2O2的最佳预处理条件:NaOH浓度为7g/L,H2O2体积分数为0.7%,底物浓度为50g/L,处理时间为24h.在优化的工艺条件下,玉米秸秆的还原糖产量达到了0.417 g/g,H2O2用量减少了30%,废水排放量减少了60%.     

沼肥对小白菜产量及品质的影响

采用田间试验方法研究了沼肥的不同处理对小白菜产量和品质的影响.结果表明:低量沼肥处理的小白菜产量最高,单产为1 364.31 kg/667 m2,与对照相比增幅为23%;从品质指标来看,高量沼肥处理的小白菜维生素C含量最佳,维生素C含量达35.621 mg/100 g,比对照增加了44.948%,与其他处理相比极显著;低量沼肥处理的小白菜可溶性糖含量最高,含量为219.307mg/kg,比对照增加24.032%;中量沼肥处理的小白菜硝酸盐含量最低,为4.63 mg/kg,与对照相比降幅为52.23%.     

Diminution of economic yield as affected by pruning and chemical manipulation of Jatropha curcas L.

Jatropha shrubs grow tall if left non-pruned. Pruning helps to keep the height within harvestable distances. Since, Jatropha flowers are borne on leaf axils of new growth in the season, pruning is supposed to increase fruiting because of formation of more number of lateral branches due to suppression of apical dominance. However, results of exploratory studies revealed drastic reduction of fruit yield after pruning. The results assume importance because lesser yield obtained owing to pruning would be uneconomical, both to the growers on account of diminished returns and to the biodiesel industry on account of being idle because of short seed supply. In this report, we found that paclobutrazol (PBZ) application induced flowering and fruiting in pruned shrubs and partially made up for the yield loss, besides keeping a lower plant height. With PBZ application, the yield reduction compared to non-pruned shrubs was limited to 67%, while 98% reduction in capsule yield was observed in untreated pruned shrubs. Paclobutrazol application along with pruning altered the morphology and vegetative growth of Jatropha, producing shrubs with smaller leaves with enhanced chlorophyll and nitrogen content and increased photosynthetic rate. It was found that though more secondary branching is induced in pruned plants, lesser tertiary branches on them results in no additional advantage with respect to total branches. However, the important objective of keeping the branches nearer to the ground is met. The effect of the treatments in terms of energy output from oil, de-oiled cake, capsule shell/husk has also been reported.     

Biomass productivity and wood energy of Salix species after 2 years growth in SRIC fertilized with wastewater sludge

The energy equivalent of willows in short-rotation intensive culture (SRIC) varies in terms of yield and woody biomass characteristics. Three willow species (Salix discolor Mühl., Salix petiolaris Smith and Salix viminalis L.) were planted on two sites, well-drained and poorly drained, in two different densities (20 000 and 30 000 plants per ha). Four doses of dried and granulated sludge were applied: the equivalents of 0, 100, 200 and 300 kg “available” N per ha. At the end of the second season, above-ground biomass was similar for S. discolor and S. viminalis, and greater than that of S. petiolaris on both sites and for all sludge treatments. On the well-drained site, each increment in the sludge dose significantly increased the performance of the species, regardless of plant density. Fertilized with a sludge dose equivalent to 300 kg N per ha, S. viminalis and S. discolor yielded 30.17 and 24.97 t/ha of dry matter respectively. On the poorly drained site, differences in performance were also observed between fertilized and unfertilized plots, but not among the various treatments. The calorific value of the wood of the three species being similar (19.21–19.59 kJ/g), the energy equivalent of a hectare of willows is proportional to the yield of each species. Thus the energy equivalent of S. viminalis and S. discolor is two to three times that of S. petiolaris. S. viminalis had the highest woody biomass quality, with an FVI (fuelwood value index) of 1030.58 (100%), followed by S. petiolaris with 954.25 (92.6%) and S. discolor with 849.08 (82.4%).     

Effect of the atmosphere on chemical composition and electrochemical properties of solid electrolyte interface on electrodeposited Li metal

Many efforts have been paid to realize the superior anodes for future Li batteries in either the dry Ar atmosphere or the dry air atmosphere. In this work, in order to clarify the effects of such atmospheres, the most reactive anodes of Li were freshly electrodeposited under the dry Ar or under the dry air condition. The Solid Electrolyte Interface (SEI) formed during the electrodeposition of Li anodes is revealed to have a different chemical composition and protective feature. The Li deposited under the dry air was revealed to have longer cycle life in the electrolyte than that deposited in Ar, even in the electrolyte containing ionic liquid. From the XPS results, the SEI formed in dry air is proved to be different from that formed in Ar gas atmospheres, that is, the SEI formed in dry air consists of Li₂CO₃ and Li nitride. In order to improve the performance of the anodes, the atmosphere for the initial preparation of the anode/electrolyte interface should be tuned.     

Effects of pretreatment methods on solubilization of beet-pulp and bio-hydrogen production yield

Sugar processing wastewater and beet-pulp are two major waste streams of sugar-beet processing plants. Contrary to wastewater, beet-pulp is generally used as animal feed in cattle-raising industry. However, it can serve as a substrate for bio-hydrogen production which corresponds to a higher valorization of beet-pulp. Moreover, pretreatment of lignocellulosic materials like beet-pulp is needed in order to improve overall energy efficiency and enable economic feasibility of bio-hydrogen production. Therefore, the effect pretreatment methods (alkaline, thermal, microwave, thermal-alkaline and microwave-alkaline) on bio-hydrogen production from sugar beet-pulp through dark fermentation were investigated in this study. Reactors pretreated with alkaline, microwave-alkaline and thermal-alkaline methods yielded significant solubilization of beet-pulp compared to others. Therefore, in the second phase of the study, they were used to pretreat the beet-pulp which was then subjected to dark fermentation for bio-hydrogen production. Maximum bio-hydrogen production yield of 115.6 mL H₂/g COD was observed in reactor which contained alkaline pretreated beet-pulp.