Diamond and methane formation from the chemical decomposition of polyethylene at high pressures and temperatures

Polyethylene (C2H4)n was compressed to pressures between 10 and 30 GPa in a diamond anvil cell (DAC) and laser heated above 2500 K for approximately one second. This resulted in the chemical decomposition of the polymer into carbon and hydrocarbon reaction products. After quenching to ambient temperature, the decomposition products were measured in the DAC at pressures ranging from ambient to 29 GPa using a combination of x-ray diffraction (XRD) and small angle x-ray scattering (SAXS). XRD identified cubic diamond and methane as the predominant product species with their pressure–volume relationships exhibiting strong correlations to the diamond and methane equations of state. Length scales associated with the diamond products, obtained from SAXS measurements, indicate the formation of nanodiamonds with a radius of gyration between 12 and 35 nm consistent with 32–90 nm diameter spherical particles. These results are in good agreement with the predicted product composition under thermodynamic and chemical equilibrium.

Changes in the concentration of methane in the ecosystem in vitro against the background of Asteraceae family plants biomass

The assessment of Asteráceae Family Plants (rhizomes and roots of elecampane and wormwood) influence on the process of methane formation in the rumen ecosystem and metabolic processes was carried out. Studies (in vitro) were carried out using ANKOM Daisy II incubator (modifications D200 and D200I) according to a specialized method. Rumen contents were obtained from beef bulls with chronic rumen fistula. Gas analysis of air and volatile fatty acids samples was performed by gas chromatography. The results of the study showed that different dosages of phytobiotic preparations did not significantly affect the characteristics of fermentation in vitro. Phytobiotic preparations of elecampane and wormwood reduce the production of methane in the ruminal fluid, which may be associated with various active components or dosages of their administration.

ENERGY SAVING OF MODULAR BUILDINGS WITH THE HELP OF BIOGAS TECHNOLOGIES

Ukraine has significant land resources for agriculture and is able to provide its population not only with food but also with raw materials for bioenergy. The article presents a graph of heat capacities and the distribution of heat flows in a bioreactor. The dependences for determining the heat fluxes of flat and cylindrical surfaces are presented. The article outlines the present state of utilization of fallen leaves of trees. The method of utilization by anaerobic fermentation is proposed. The design of bioreactors and the main factors influencing the methane formation process are considered. The methodology for calculating the biogas production process is presented. The productivity of the bioreactor has been determined, depending on the temperature of the raw material and the time of hydraulic resistance

Potential of graded doses of neem (Azadirachta indica) seed oil on ruminal fermentation characteristics, degradability, and methane formation in vitro

Neem (Azadirachta indica) belongs to Meliaceae family, represented mainly by trees, and widely cultivated and adapted in many tropical regions. The objective of this study was to evaluate the effect of increasing doses of neem seed oil (NSO) on ruminal methane (CH4) formation, diet degradability, and fermentation characteristics 24 h of in vitro incubation. Treatments were randomly designed to four doses of NSO supplemented to the basal diet (0, 20, 40, or 60 ml/kg DM). Increasing NSO dose resulted in a quadratic decrease (P < 0.05) in net gas (expressed as ml/g DM and ml/g TDOM) and CH4 (expressed as ml/g TDNDF) production, while CH4 (expressed as ml/g TDOM), acetate and propionate proportions decreased linearly confirming a dose-related effect. A quadratic increase in TDOM and linear increase (P = 0.023) in DNDF, NH3-N concentrations, and total protozoal counts were observed. However, a linear increase (P = 0.009) was found in the ruminal butyrate proportion and partitioning factor as dietary NSO supplementation increased. In conclusion, dietary NSO supplementation mediated some desirable fermentation patterns, reducing ruminal NH3-N concentration and CH4 production with some adverse effects on fiber degradability. However, practical research under long-term conditions is required for further investigation.

The impact of aerobic pretreatment of agro and industrial wastes on their biomethanation potential in Nisargruna technology

Anaerobic digestion is among the essential biological techniques used for stabilization of organic sludge from sewage and highly concentrated efflu-ents from food processing industries. It also recycles the municipal solid wastes into compost with simultaneous production of methane. The current study was performed to estimate the biomethanation potential of various agro- and industrial wastes like Jatropha de-oil cake, prawn shells, chicken feathers, bagasse, rice straw and wheat husk by mimicking the conditions in the biphasic Nisargruna biogas plant. A small volume of samples was chemi-cally characterized and allowed to decompose under aerobic and anaerobic conditions to determine the effect of aerobic predigestion (i.e. phase 1 of Nisargruna plant) on final methane production. The biogas produced was quantified by downward displacement of water. The observations indicated that approximately 60-80% methane was produced when Jatropha de-oil cake, prawn shells and rice straw was used. Conversely, the wheat straw and sugarcane wastes showed less methane formation, which may be due to the presence of complex polymers like lignocellulose and silica that considerably reduces the metabolic potential of microorganisms.

The rumen microbiome inhibits methane formation through dietary choline supplementation

Enteric fermentation from ruminants is a primary source of anthropogenic methane emission. This study aims to add another approach for methane mitigation by manipulation of the rumen microbiome. Effects of choline supplementation on methane formation were quantified in vitro using the Rumen Simulation Technique. Supplementing 200 mM of choline chloride or choline bicarbonate reduced methane emissions by 97–100% after 15 days. Associated with the reduction of methane formation, metabolomics analysis revealed high post-treatment concentrations of ethanol, which likely served as a major hydrogen sink. Metagenome sequencing showed that the methanogen community was almost entirely lost, and choline-utilizing bacteria that can produce either lactate, ethanol or formate as hydrogen sinks were enriched. The taxa most strongly associated with methane mitigation were Megasphaera elsdenii and Denitrobacterium detoxificans, both capable of consuming lactate, which is an intermediate product and hydrogen sink. Accordingly, choline metabolism promoted the capability of bacteria to utilize alternative hydrogen sinks leading to a decline of hydrogen as a substrate for methane formation. However, fermentation of fibre and total organic matter could not be fully maintained with choline supplementation, while amino acid deamination and ethanolamine catabolism produced excessive ammonia, which would reduce feed efficiency and adversely affect live animal performance.

Potential Routes and Innovative Technologies for Valorisation of Cassava Peels

The large-scale processing of Cassava (Manihot esculenta Crantz.) generates significant quantities of solid wastes annually. Cassava peels (CP) account for 5 wt.% - 30 wt.% of wastes from the processing of cassava tubers. The poor disposal and management of CP pose risks to human health, safety and the environment. Therefore, there is an urgent need to identify and examine low cost, socially acceptable and environmentally friendly strategies to mitigate the immediate and long terms disposal and management challenges. Lack of such measures results in the accumulation of CP wastes, which are currently buried, combusted, or dumped in open fields. Therefore, this paper reviewed the potential routes for the biochemical, thermochemical, and plasma valorisation of CP. The literature reviewed revealed that biochemical technologies such as anaerobic digestion (AD) and fermentation are the most widely utilised approaches currently adopted for CP valorisation. AD produces biogas (methane 50-72 vol. % and carbon dioxide 25-45 vol. %), whereas fermentation yields bioethanol. However, the numerous challenges such as substrate-induced inhibition, associated with the biochemical processes hamper microbial degradation, methane formation, and process efficiency. Furthermore, the processes generate secondary wastes or digestate/sludge, which requires additional processing before disposal. Therefore, innovative thermal, thermochemical, and plasma technologies were proposed to valorise CP into syngas, biofuels, bioenergy, biochemicals, and fertilizers, among others. However, the waste products of fermentation cannot be effectively utilised as bio-fertilizers, whereas bioethanol causes corrosion in engines. Overall, the biochemical, thermal, thermochemical and plasma technologies can effectively valorise CP for effective net energy generation.

The missing enzymatic link in syntrophic methane formation from fatty acids

The microbial production of methane from organic matter is an essential process in the global carbon cycle and an important source of renewable energy. It involves the syntrophic interaction between methanogenic archaea and bacteria that convert primary fermentation products such as fatty acids to the methanogenic substrates acetate, H2, CO2, or formate. While the concept of syntrophic methane formation was developed half a century ago, the highly endergonic reduction of CO2 to methane by electrons derived from β-oxidation of saturated fatty acids has remained hypothetical. Here, we studied a previously noncharacterized membrane-bound oxidoreductase (EMO) from Syntrophus aciditrophicus containing two heme b cofactors and 8-methylmenaquinone as key redox components of the redox loop–driven reduction of CO2 by acyl–coenzyme A (CoA). Using solubilized EMO and proteoliposomes, we reconstituted the entire electron transfer chain from acyl-CoA to CO2 and identified the transfer from a high- to a low-potential heme b with perfectly adjusted midpoint potentials as key steps in syntrophic fatty acid oxidation. The results close our gap of knowledge in the conversion of biomass into methane and identify EMOs as key players of β-oxidation in (methyl)menaquinone-containing organisms.

Power supply of measuring sensors when performing experimental studies of electrical thermal mechanical system

The main part of scientific research is the results of the experiment, because they make it possible to establish the existing dependencies of the course of processes on a real object, confirm theoretical calculations and a mathematical model of an electrothermal-mechanical system. The work is devoted to the issue of experimental research of power supplies for measuring and recording equipment. According to the purpose, a technique was proposed by which experimental studies of the presence of pulses, noise and fluctuations in the output voltage of pulse and transformer power supplies were carried out. The influence of the deviation of the output voltage on the fluctuations of the voltage readings on the measuring and recording equipment has been investigated. Based on the results of experimental studies of power supplies, the proposed technique can be taken as a basis for selecting power supplies in accordance with the requirements for the required accuracy of reading indicators from the measuring equipment in accordance with their accuracy class, within the total error permissible for this type of experiment. A power source for measuring and recording equipment was selected for experimental studies of an electrothermal-mechanical system to intensify the process of methane formation in a biogas reactor in order to determine as accurately as possible the energy costs for biogas production, due to the fact that the process of producing biogas is long, therefore, a large error in determining energy costs affects an increase in actual energy costs in production in relation to the calculated and experimental data. The practical value of the work lies in the fact that the use of power supplies with a lower ripple of the output voltage in experiments will reduce the processing time of the obtained data arrays, increase the efficiency of the experiment and the accuracy of the revealed dependencies. The methodology presented in the work also makes it possible to more efficiently use financial resources for the purchase of devices in the preparation and conduct of scientific and experimental research. Keywords: power supply, voltage pulse, accuracy, scientific research, experiment, PeakTech