Different Types Of Organic Materials Research Articles

Analysis of Thermodynamic Events Taking Place during Vacuum Drying of Corn

Agricultural materials (LF products) can be considered biologically living organisms due to their structure and the composition of colloidal capillary-porous substances in them. They contain a large number of microscopic pores, microcapillaries and macrocapillaries, in which water is able to pass from the inner parts to the surface of the grain, and vice versa. Thus, it can be concluded that drying is an important and demanding aspect of agricultural production. To determine the optimal drying process for agricultural cereals from a nutritional, energy, economic and environmental point of view, it is necessary to address in detail the application of the technology of vacuum drying from a thermodynamic point of view. An analysis of the research results shows that drying temperature, harvest date and corn variety can significantly affect the properties of the main components of corn grain. This study investigates the individual technological parameters of the vacuum drying process for corn, such as the pressure used in the drying chamber, the grain drying temperature and the heating time, in order to achieve a maximum reduction in water content. The aim of the investigation is to determine the optimal parameters for the design of a functional prototype of a vacuum dryer. For this purpose, laboratory and semi-operational experiments using different types of organic materials are necessary. The structural design of the individual elements of the vacuum dryer is based on an analysis of laboratory and experimental tests, whose results are presented in this article.

Effects of reductive soil disinfestation combined with different types of organic materials on the microbial community and functions.

Reductive soil disinfestation (RSD) is an effective method to inhibit soilborne pathogens. However, it remains unclear how RSD combined with different types of organic materials affects the soil ecosystems of perennial plants. Pot experiments were conducted to investigate the effects of RSD incorporated with perilla (PF), alfalfa (MS), ethanol, and acetic acid on soil properties, enzyme activities, microbial communities and functions, and seedling growth. Results showed that RSD-related treatments improved soil properties and enzyme activities, changed microbial community composition and structure, enhanced microbial interactions and functions, and facilitated seedling growth. Compared with CK, RSD-related treatments increased soil pH, available nitrogen, and available potassium contents, sucrase and catalase activities, and decreased soil electric conductivity values. Meanwhile, RSD-related treatment also significantly reduced the relative abundance of Fusarium while increasing the relative abundance of Arthrobacter, Terrabacter, and Gemmatimonas. The reduction was more evident in PF and MS treatment, suggesting the potential for RSD combined with solid agricultural wastes to suppress pathogens. Furthermore, the microbial network of RSD-related treatment was more complex and interconnected, and the functions related to carbon, nitrogen, sulfur, and hydrogen cycling were significantly increased, while the functions of bacterial and fungal plant pathogens were decreased. Importantly, RSD-related treatments also significantly promoted seed germination and seedling growth. In summary, RSD combined with solid agricultural wastes is better than liquid easily degradable compounds by regulating the composition and function of microbial communities to improve soil quality and promote plant growth.IMPORTANCEReductive soil disinfestation (RSD) is an effective agricultural practice. We found that RSD combined with solid agricultural wastes is better than that of liquid easily degradable compounds, may improve soil quality and microbial community structure, inhibit the proliferation of pathogenic bacteria, and contribute to the growth of replanted crops. Thus, RSD combined with solid agricultural wastes is more effective than liquid easily degradable compounds.

Cryopreservation Practices: Transforming Temporal Horizons

Cryopreservation practices allow us to deep-freeze different types of organic material for potential future use, creating a liminal state between life and death. Professor Thomas Lemke and his team in the CRYOSOCIETIES project are investigating how this ‘suspended life’ is transforming temporal horizons and our understanding of health, fertility and biodiversity.

Recent advances in developing organic positive electrode materials for rechargeable aluminum-ion batteries

Rechargeable aluminum-ion (Al-ion) batteries have been highlighted as a promising candidate for large-scale energy storage due to the abundant aluminum reserves, low cost, high intrinsic safety, and high theoretical energy density. However, the strong Coulombic interaction between the high charge density Al3+ and electrode host lattices leads to poor kinetics and insufficient cycle life in Al-ion batteries with inorganic electrodes. In contrast, organic electrode materials exhibit the advantages of designable molecular structure, flexible framework, coordinated energy storage chemistry, and resource sustainability. Nevertheless, organic materials encounter inherently high solubility, low active center utilization, and low electrical conductivity. Herein, the recent advances in developing organic positive electrode materials for Al-ion batteries is reviewed, and the charge storage mechanisms and electrochemical performances of different types of organic materials are systematically summarized. This review also discusses design strategies to improve specific capacity, operating voltage, cycle life, and rate capability of organic positive electrodes for Al-ion batteries. Finally, the challenges and research outlook toward high performance Al/organic batteries are presented.

Tracing Organic-Inorganic Interactions by Light Stable Isotopes (H, Li, B, O) of an Oil-Bearing Shale and its Clay Fraction During Hydrous Pyrolysis

AbstractTracing interactions during burial-induced organic maturation and associated clay-material alteration is of prime importance for understanding both the individual and combined mineral and organic processes. In the present study the light elements B, Li, O, and H of a sample from oil-prone Eocene Kreyenhagen Shale from San Joaquin Basin (California) were examined. The natural burial-induced temperature increase was simulated by pyrolysis experiments at progressively increasing temperatures (270–365°C) and for varied durations (72–216 h) applied to the whole rock and its <2 μm fraction. The illite structure as well as the K-rich interlayers of the illite-smectite mixed layers were not affected by the pyrolysis experiments and the smectite-rich interlayers did not collapse, while the soluble minerals and the organic matter were altered. The distribution pattern of the rare-earth elements (REEs) from untreated whole rock and of its pyrolyzed equivalents are within analytical uncertainty, which confirms that the changes induced by pyrolysis experiments were minimal in the bulk sample. Conversely, the REEs from the <2 μm fractions were modified significantly, suggesting that the whole rocks and the <2 μm fractions may contain different types of organic materials. Also, only the carbonates, oxides, chlorides, and organic matter were affected together with the smectite-rich interlayers of the illite-smectite structure. Bitumen coating of the smectite interlayers probably increased the amount of B of organic origin in their sites. The δ11B and δ7Li of the successively expelled hydrocarbon phases changed with increasing pyrolysis temperatures, together with the B and Li contents of the hydrocarbon-related fluids. On the basis of the δ11B and δ7Li from pyrolyzed clay fractions, the B released successively was not isotopically homogeneous, probably depending on how the type of organic matter decomposed during the successive pyrolysis steps, and on which components were released. The δ11B of organic-B increased progressively from –2‰ at low experimental temperature up to +9‰ at the highest temperature. The calculated δ7Li that was released also increased relative to the value of the outcropping sample used as a reference, but it remained almost constant from –7‰ at 310°C for 72 h to –8‰ at 365°C for 216 h. The δ18O values of the <2 μm size fractions decreased significantly during pyrolysis above 300°C, but the δD changes were rather modest. The total organic carbon (TOC) remained statistically constant after pyrolysis to 300°C, as did the δ7Li values. The pyrolysis experiments in the present study suggest the presence of bitumen-coated smectite interlayers that could have been misidentified as dehydrated smectite in the literature. Together with abnormal illite K-Ar ages, the occurrence of such bitumen-coated illite-smectite interlayers occurring in source and reservoir rocks could indicate the timing of hydrocarbon maturation relative to illitization.

Replacing Synthetic Nitrogen Fertilizer with Different Types of Organic Materials Improves Grain Yield in China: A Meta-Analysis

Synthetic nitrogen fertilizer substitution (NSS) with different types of organic material is a cleaner agricultural practice for reducing the application of synthetic N input in farmlands while also relieving the environmental issues caused by the discharge of organic wastes. However, the effects of the NSS practice on crop yields, being the primary objective of agricultural activity, is still uncertain in China. This study conducted a meta-analysis to assess the impacts of the NSS practices with different types of organic materials on crop yields. Results showed that the average crop yield was increased by 3.4%, with significant differences under NSS, thereby demonstrating that this practice contributed to improving crop yields, especially of rice and maize. According to published reports, the NSS practices involving chicken manure, pig manure, and crop straw increased crop yields by 4.79, 7.68, and 3.28%, respectively, with significant differences, thus demonstrating the superior effects needed for replacing synthetic N fertilizer. Moreover, substitution ratios (SR) between 0% and 60% could be suggested when using the NSS practice, with the high SR recommended when the original soil fertility was adequate for crops. Considering the long-term effects of applied organic materials, improving the grain yield with the NSS practice should be expected in the long-term. By effectively applying the NSS, this study attempted to scientifically decide on the type of organic materials and the appropriate SR based on the conditions of the soil and the crop. The results provide research information for the development of clean agricultural production and food security in China.

Development of optimisation model for black soldier fly-based aquaculture feed supply chains in Malaysia

Aquaculture is identified as one of the critical food supplies in Malaysia. Due to the increasing demand for aquaculture products, the demand for protein sources for fish feed is also increased accordingly. Black soldier fly larvae is identified as one of the main protein sources that can be used in fish feed. Such larvae can be grown using different types of organic materials, such as food waste, agriculture waste, etc. As Malaysia is the second-largest palm oil producer in the world, therefore, a large number of agricultural wastes, also known as palm-based biomass (e.g., empty fruit bunches, mesocarp fibre, decanter cake, etc.) are generated annually. Based on the current industry practise, palm-based biomass can be converted into value-added products. However, using palm-based biomass as feedback to grow black soldier fly larvae is a relatively recent discovery. Thus, a viable supply chain model has yet to be established. In this work, a mathematical optimisation model is developed via commercial optimisation software (Lingo v. 16) to synthesise an optimum black soldier fly-based aquaculture feed supply chain that utilised palm–based biomass as the feedstock. Based on the optimised result, the annual operating cost of the aquaculture feed supply chain is estimated as RM 5.2 million.

Effect of combining straw‐derived materials and wood ash on alkaline soil carbon content and the microbial community

AbstractThe return of organic materials to cultivated fields to improve soil quality and to sequester carbon are widely studied, but the effects of combining different types of organic material on soil microbial diversity and community structure are poorly understood, particularly in alkaline soils. An incubation experiment was performed to study the effects of incorporating two straw‐derived materials (fresh straw and semi‐decomposed straw) alone or in combination with wood ash. The organic carbon content of soil treated with straw‐derived materials was significantly higher than that of soil with no straw and wood addition, but there was no significant difference between the fresh straw and semi‐decomposed straw treatments. Microbial diversity was decreased by the addition of straw on day 7; however, the combination of fresh/semi‐decomposed straw with wood ash increased bacterial diversity on day 118, and the combination of semi‐decomposed straw with wood ash increased fungal diversity. Fresh straw combined with wood ash significantly increased the abundance of Ascomycota by 15.5% relative to that of soil treated with semi‐decomposed straw, and semi‐decomposed straw combined with wood ash increased the abundance of Basidiomycota by 40.5% relative to that of soil treated with fresh straw. Amendment with straw‐derived materials and wood ash shaped the bacterial community in alkaline soil by changing the soil organic carbon, dissolved organic carbon and pH, and the characteristics of straw‐derived materials and wood ash shaped the fungal community. Straw‐return modes that employ semi‐decomposed straw and wood ash addition can maintain organic carbon levels and improve the soil micro‐environment.Highlights Combining straw‐derived materials and wood ash affects alkaline soil carbon content and the microbial community. The effects of fresh and semi‐decomposed wheat straw on soil microorganisms and soil carbon content are reported for the first time. The combination of semi‐decomposed wheat straw and wood ash enhanced soil fungal diversity and Basidiomycota abundance. Semi‐decomposed wheat straw and wood ash can maintain organic carbon levels and improve the soil micro‐environment.

Polyimide/metal-organic framework hybrid for high performance Al - Organic battery

Aluminum(Al)-organic batteries are considered as a great alternative option for next generation energy storage devices. The recent Al-organic batteries propose new storage mechanisms of cationic aluminum complex ([AlClx]3−x, x ​= ​1 or 2) distinguished from traditional AlCl4−, represent an important breakthrough for aluminum batteries. However, the electrochemical storage mechanisms (value of x in [AlClx]3−x) are related to different types of organic materials, the poor cycling stability caused by inevitable dissolution of organic materials in electrolyte, and the complex synthetic process restrict the development of Al-organic batteries. Herein, polyimide (PI)/metal-organic frameworks (MOFs) hybrid material synthesizing from a facile one-pot strategy as cathode material in Al-organic battery is reported, providing with high specific capacity and excellent cycle stability. The PI/MOFs hybrid electrode achieves capacity of 83 ​mA ​h ​g−1 ​at 1000 ​mA ​g−1 with high coulombic efficiency (almost 100%). It also exhibits an excellent cycle performance of 1800 cycles with only a capacity decay of 0.0067% per cycle. Furthermore, the electrochemical storage mechanism of PI/MOFs is evaluated by ex-situ X-ray photoelectron spectroscopy and energy dispersive X-ray spectrum, which demonstrate that the cationic chloroaluminates interact with reduced carbonyl bonds in PI during discharge is AlCl2+. These findings are of great significance for the basic understanding of the working mechanism of PI compound cathode in Al-organic batteries, which may serve as a solid foundation for further development of novel organic cathode materials and their composites for Al-organic batteries.

Generation of Viable Bacterial and Fungal Aerosols during Biomass Combustion

Biomass combustion is known to be one of the main contributors to air pollution. However, the influence of biomass burning on the distribution of viable bacterial and fungal aerosols is uncertain. This study aimed to examine survivability of bacteria and fungi in the post-combustion products, and to investigate the aerosolization of viable cells during combustion of different types of organic materials. Laboratory experiments included a small-scale combustion of organic materials contaminated with microorganisms in order to determine the survivability of microbes in the combustion products and the potential aerosolization of viable cells during combustion. Field experiments were completed during intentional and prescribed biomass burning events in order to investigate the aerosolization mechanisms that are not available at the laboratory scale. Laboratory experiments did not demonstrate aerosolization of microorganisms during biomass combustion. However, the relatively high survival rate of bacteria in the combustion products ought to be accounted for, as the surviving microorganisms can potentially be aerosolized by high velocity natural air flows. Field investigations demonstrated significant increase in the bioaerosol concentration above natural background during and after biomass combustion.

Cash for trash: an agro-economic value assessment of urban organic materials used as fertilizers in Cameroon

The rapid expansion of cities in sub-Saharan Africa generates increasing volumes of diversified organic wastes that require management and a high population need for local and fresh vegetables. Linking the different sources of organic materials generated in these cities with the needs of local food producers for fertilizers prepared from recycled organic materials is challenging. This requires that producers obtain the results they expect from the organic materials they recycle. Thus, recycling these organic materials in their raw form or after composting presents an opportunity for periurban agriculture, although the great variability in the quantity and quality of these materials raises questions about the consistency between their agronomic value and their economic value. In two large cities of Cameroon (Yaoundé and Bafoussam), different types of organic materials were sampled: unprocessed livestock waste and composts from manure or municipal solid waste. From an agronomic perspective, we calculated the fertilization value based on the nutrient (nitrogen, phosphorus, and potassium) content of the organic materials. From an economic perspective, we calculated the value based on the nutrient content of the organic materials and their substitution unit prices and recorded the current market price. This is the first time that this combined approach has been used in sub-Saharan Africa. Our results showed considerable variability and discrepancy in both the agronomic and the economic values. The market prices overvalued the urban composts by a factor of 6, while chicken feces were undervalued by a factor of 3. The unprocessed organic materials were the most interesting from an economic and agronomic perspective. Our findings suggest that (i) the composting process needs to be improved and (ii) the humus potential should be calculated to better assess the amendment value of organic materials and as a basis for adjusting their market price.

Influences of Nitrogen Application Levels on Properties of Humic Acids in Chernozem Amended with Different Types of Organic Materials

The objective of this study was to examine the structure changes in humic acids (HAs) in Chernozem after the application of different types of organic materials (OMs) under an indoor simulation condition for plastic mulched drip irrigation, measured with Fourier transform infrared (FTIR) spectroscopy. The biotechnological extract of fulvic acid (BFA), decomposed sheep manure (M), corn straw pellets (Ps) and corn straw powder (Pr) were used as the four OMs for testing, and they were applied to Chernozem at the same amount of actual material; three nitrogen (N) levels (no N, low N, and high N supply) were applied to each type of (OMs), separately. The total culture period was set to 90 days and soil sampling was taken at 0, 30, 60 and 90 days, respectively. The results showed that different types of OMs exerted different effects on Chernozem based on the FTIR spectra of HAs. The application of M combined with high N supply was the best way to fertilize Chernozem, under which the H-bonded OH groups and aromatic compounds were enhanced, resulting in increased soil carbon (C) sequestration; while the carbohydrates in HAs was easily consumed as microbial energy substance. The HAs from the Chernozem amended with BFA became more aliphatic, simpler and younger. High N supply was beneficial for increasing the complexity of HAs from Chernozem amended with Ps, but was not conducive to soil cation retention. Within a short time of incubation, the application of Pr combined with high N was detrimental to the C sequestration in Chernozem, and inhibited the consumption of carbohydrates by microorganisms.

Role of anaerobic bacteria in biological soil disinfestation for elimination of soil-borne plant pathogens in agriculture.

Biological soil disinfestation (BSD) or reductive soil disinfestation (RSD) is an environmental biotechnology to eliminate soil-borne plant pathogens based on functions of indigenous microbes. BSD treatments using different types of organic materials have been reported to effectively control a wide range of plant pathogens. Various studies have shown that development of reducing or anoxic conditions in soil is the most important aspect for effective BSD treatments. Substances such as organic acids, FeS, or phenolic compounds generated in the treated soil have been suggested to contribute to inactivation of pathogens. Additionally, anaerobic bacteria grown in the BSD-treated soil may produce and release enzymes with anti-pathogenic activities in soil. Clone library analyses as well as a next-generation sequence analysis based on 16S rRNA genes have revealed prosperity of obligate anaerobic bacteria from the class Clostridia in differently treated BSD soils. Two anaerobic bacterial strains isolated from BSD-treated soil samples and identified as Clostridium beijerinckii were found to decompose major cell wall polysaccharides of ascomycetous fungi, chitosan and β-1,3-glucan. C. beijerinckii is a species most frequently detected in the clone library analyses for various BSD-treated soils as a closely related species. The two anaerobic isolates severely degraded mycelial cells of the Fusarium pathogen of spinach wilt disease during anaerobic co-incubation of each isolate and the Fusarium pathogen. These reports suggest that antifungal enzymes produced by predominant anaerobic bacteria grown in the BSD-treated soil play important roles to control soil-borne fungal pathogens. Further studies using different bacterial isolates from BSD-treated soils are expected to know their anti-pathogenic abilities.

An Improved Multilayer Compacted Clay Liner by Adding Bentonite and Phosphate Compound to Sandy Soil

Landfilling of municipal solid waste produces leachate containing heavy metals and different types of organic materials. On the other hand, it has been proven by researchers that dicalcium phosphate (DCP) is applicable for stabilizing of different heavy metals through the contaminated soil. This study aimed to investigate the effect of DCP on the permeability, cohesion and friction angle of a sand-bentonite liner. DCP was added by 0.2% of the dry weight of the base soil. Then, the permeability and shear strength were measured with water and synthetic leachate to assess the compatibility. Permeability coefficient of the sandy soil improved from about 10−4 cm/s to less than 10−7 cm/s. Results imply that DCP increases the compatibility of sand-bentonite mixture, and the leachate has less influence on this type of liner. By increasing the applied bentonite up to 6% in the base material liner, the internal friction angle reduces first and remains almost constant afterwards. For a certain vertical stress, adding 0.2% DCP to the sand-bentonite mixture increased the shear strain at the maximum shear strength and presents a positive effect. Therefore, a multilayer compacted clay liner is proposed that consists of a layer of DCP improved soil to increase the stabilization of heavy metals.

A density functional theory study on the thermodynamic and dynamic properties of anthraquinone analogue cathode materials for rechargeable lithium ion batteries.

Organic redox compounds have become the emerging electrode materials for rechargeable lithium ion batteries. The high electrochemical performance provides organic electrode materials with great opportunities to be applied in electric energy storage devices. Among the different types of organic materials, conjugated carbonyl compounds are the most promising type at present, because only they can simultaneously achieve, high energy density, high cycling stability, and high power density. In this research, a series of heteroatom substituted anthraquinone (AQ) derivatives were designed theoretically so that the high theoretical capacity of AQ remained. The discharge and charge mechanism as well as the thermodynamic and dynamic properties of AQ and its derivatives were investigated using first-principles density functional theory. Using heteroatom substitution, both the thermodynamic and dynamic properties of AQ as cathode materials could be largely improved. Among these conjugated carboxyl compounds, BDOZD and BDIOZD with a simultaneously high theoretical capacity and high working potential exhibit the largest energy density of about 780 W h kg-1, which is 41% larger than that of AQ. The PQD with the smallest value of λ gives the largest charge transfer rate constant, which is about four times as large as the prototype molecule, AQ. The most interesting finding is that the lithium ion transfer plays a very important role in influencing both the discharge potential and electrochemical charge transfer rate. The present study illustrates that theoretical calculations provide a highly effective way to discover potential materials for use with rechargeable lithium ion batteries.

The nature of organic records in impact excavated rocks on Mars.

Impact ejected rocks are targets for life detection missions to Mars. The Martian subsurface is more favourable to organic preservation than the surface owing to an attenuation of radiation and physical separation from oxidising materials with increasing depth. Impact events bring materials to the surface where they may be accessed without complicated drilling procedures. On Earth, different assemblages of organic matter types are derived from varying depositional environments. Here we assess whether these different types of organic materials can survive impact events without corruption. We subjected four terrestrial organic matter types to elevated pressures and temperatures in piston-cylinder experiments followed by chemical characterisation using whole-rock pyrolysis-gas chromatography-mass spectrometry. Our data reveal that long chain hydrocarbon-dominated organic matter (types I and II; mainly microbial or algal) are unresistant to pressure whereas aromatic hydrocarbon-dominated organic matter types (types III and IV; mainly land plant, metamorphosed or degraded, displaying some superficial chemical similarities to abiotic meteoritic organic matter) are relatively resistant. This suggests that the impact excavated record of potential biology on Mars will be unavoidably biased, with microbial organic matter underrepresented while metamorphosed, degraded or abiotic meteoritic organic matter types will be selectively preserved.

Effect of cysteine and humic acids on bioavailability of Ag from Ag nanoparticles to a freshwater snail

Metal-based engineered nanoparticles (NPs) will undergo transformations that will affect their bioavailability, toxicity and ecological risk when released to the environment, including interactions with dissolved organic material. The purpose of this paper is to determine how interactions with two different types of organic material affect the bioavailability of silver nanoparticles (AgNPs). Silver uptake rates by the pond snail Lymnaea stagnalis were determined after exposure to 25nmoll−1 of Ag as PVP AgNPs, PEG AgNPs or AgNO3, in the presence of either Suwannee River humic acid or cysteine, a high-affinity thiol-rich organic ligand. Total uptake rate of Ag from the two NPs was either increased or not strongly affected in the presence of 1–10mgl−1 humic acid. Humic substances contain relatively few strong ligands for Ag explaining their limited effects on Ag uptake rate. In contrast, Ag uptake rate was substantially reduced by cysteine. Three components of uptake from the AgNPs were quantified in the presence of cysteine using a biodynamic modeling approach: uptake of dissolved Ag released by the AgNPs, uptake of a polymer or large (>3kD) Ag-cysteine complex and uptake of the nanoparticle itself. Addition of 1:1 Ag:cysteine reduced concentrations of dissolved Ag, which contributed to, but did not fully explain the reductions in uptake. A bioavailable Ag-cysteine complex (>3kD) appeared to be the dominant avenue of uptake from both PVP AgNPs and PEG AgNPs in the presence of cysteine. Quantifying the different avenues of uptake sets the stage for studies to assess toxicity unique to NPs.

Decline in Performance of Biochemical Reactors for Sulphate Removal from Mine-Influenced Water is Accompanied by Changes in Organic Matter Characteristics and Microbial Population Composition

Successful long-term bioremediation of mining-influenced water using complex organic matter and naturally-occurring microorganisms in sub-surface flow constructed wetlands requires a balance between easily and more slowly degrading material. This can be achieved by combining different types of organic materials. To provide guidance on what mixture combinations to use, information is needed on how the ratio of labile to recalcitrant components affects the degradation rate and the types of microbial populations supported. To investigate this, different ratios of wood and hay were used in up-flow column bioreactors treating selenium- and sulphate-containing synthetic mine-influenced water. The degradation rates of crude fibre components appeared to be similar regardless of the relative amounts of wood and hay. However, the nature of the degradation products might have differed in that those produced in the hay-rich bioreactors were more biodegradable and supported high sulphate-reduction rates. Microorganisms in the sulphate-reducing and cellulose-degrading inocula persisted in the bioreactors indicating that bio-augmentation was effective. There was a shift in microbial community composition over time suggesting that different microbial groups were involved in decomposition of more recalcitrant material. When dissolved organic carbon (DOC) was over-supplied, the relative abundance of sulphate-reducers was low even through high sulphate-reduction rates were achieved. As DOC diminished, sulphate-reducers become more prevalent and their relative abundance correlated with sulphate concentrations rather than sulphate-reduction rate.

Room-Temperature Organic Negative Differential Resistance Device Using CdSe Quantum Dots as the ITO Modification Layer**Supported by the National Natural Science Foundation of China under Grant Nos 61106123 and 61275034, and the National Basic Research Program of China under Grant No 2013CB328705.

Room-temperature negative differential resistance (NDR) has been observed in different types of organic materials. However, detailed study on the influence of the organic material on NDR performance is still scarce. In this work, room-temperature NDR is observed when CdSe quantum dot (QD) modified ITO is used as the electrode. Furthermore, material dependence of the NDR performance is observed by selecting materials with different charge transporting properties as the active layer, respectively. A peak-to-valley current ratio up to 9 is observed. It is demonstrated that the injection barrier between ITO and the organic active layer plays a decisive role for the device NDR performance. The influence of the aggregation state of CdSe QDs on the NDR performance is also studied, which indicates that the NDR is caused by the resonant tunneling process in the ITO/CdSe QD/organic active layer structure.

Solid Fuel Generation from Urban Leaf Litter in Mixture with Grass Cuttings: Chemical Composition, Energetic Characteristics, and Impact of Preprocessing

Urban biomass from green areas is a potential resource for bioenergy recovery, which is widely unused. Different types of organic material (e.g., grass, leaf litter) usually occur in mixtures due to common collecting practice. Forty samples of grass, leaf litter (genera: Acer, Quercus, Tilia), and mixtures of both, containing one third grass or leaf litter, were investigated to evaluate the effect of the “Integrated Generation of Solid Fuel and Biogas from Biomass” (IFBB) on material and energy fluxes as well as relevant characteristics of resulting energy carriers. IFBB divides biomass into a fiber-rich press cake and a highly digestible press fluid by mashing with subsequent pressing. Ensiling of samples was successful with pH values ranging from 4.2 in grass to 4.8 in pure Tilia samples. Concentration of most minerals with exception of Ca and Mg were higher in grass than in leaf litter silage. The IFBB treatment reduced the element concentration in the press cake independently from the substrate. Linear regression models revealed high influence of the initial concentration in silage on the concentration in the press cake. The lower heating value of the press cake was nearly constant (19 MJ kg−1 DMash free) independent from mixture. Methane yields from press fluid digestion ranged from 172 (mean of leaf litter samples) to 325 lN kg−1 VS (mixture of 33 % leaf litter—66 % grass). For an evaluation of the economic and ecological potential, models of the spatial and temporal occurrence of these biomasses need to be established.