Source Of Chemical Energy Research Articles

Integration of PEM Fuel Cells and Lithium Ion Secondary Battery into a Single Hybrid Electric Energy Source – Part I: Control System

Both fuel cells and lithium-ion cells are chemical sources of electric energy. In either of these sources, energy is obtained from chemical reactions performed at the electrodes. However, different constructions of those cells causes that they are characterized by different, and in many cases opposite, properties. Their combination into a single hybrid power source can therefore lead to utilization of advantages of both of them and, at the same time, mutual elimination of their disadvantages. The article presents control assumptions, structure of control system and control algorithm of a hybrid portable electric energy source in an early stage of development – a technology demonstrator. Discussed technology demonstrator integrates PEM fuel cells with Li-ion secondary cells.

Cancer: Mitochondrial Origins.

The primacy of glucose derived from photosynthesis as an existential source of chemical energy across plant and animal phyla is universally accepted as a core principle in the biological sciences. In mammalian cells, initial processing of glucose to triose phosphate intermediates takes place within the cytosolic glycolytic pathway and terminates with temporal transport of reducing equivalents derived from pyruvate metabolism by membrane-associated respiratory complexes in the mitochondrial matrix. The intra-mitochondrial availability of molecular oxygen as the ultimate electron acceptor drives the evolutionary fashioned chemiosmotic production of ATP as a high-efficiency biological process. The mechanistic bases of carcinogenesis have demonstrated profound alteration of normative mitochondrial function, notably dysregulated respiratory processes. Accordingly, the classic Warburg effect functionally links aerobic glycolysis, aberrant production and release of lactate, and metabolic down-regulation of mitochondrial oxidative processes with the carcinogenetic phenotype. We surmise, however, that aerobic fermentation by cancer cells may also represent a developmental re-emergence of an evolutionarily conserved early phenotype, which was “sidelined” with the emergence of mitochondrial oxidative phosphorylation as a primary mechanism for ATP production in normal cells. Regardless of state-dependent physiological status in mixed populations of cancer cells, it has been established that mitochondria are functionally linked to the initiation of cancer and its progression. Biochemical, molecular, and physiological differences in cancer cell mitochondria, notably mtDNA heteroplasmy and allele-specific expression of selected nuclear genes, may represent major focal points for novel targeting and elimination of cancer cells in metastatic disease afflicting human populations. To date, and despite considerable research efforts, the practical realization of advanced mitochondrial targeted therapies has not been forthcoming.

Fast combustion waves and chemi-ionization processes in a flame initiated by a powerful local plasma source in a closed reactor.

Results are presented from experimental studies of the initiation of combustion in a stoichiometric methane-oxygen mixture by a freely localized laser spark and by a high-current multispark discharge in a closed chamber. It is shown that, preceding the stage of 'explosive' inflammation of a gas mixture, there appear two luminous objects moving away from the initiator along an axis: a relatively fast and uniform wave of 'incomplete combustion' under laser spark ignition and a wave with a brightly glowing plasmoid behind under ignition from high-current slipping surface discharge. The gas mixtures in both the 'preflame' and developed-flame states are characterized by a high degree of ionization as the result of chemical ionization (plasma density n(e)≈10(12) cm(-3)) and a high frequency of electron-neutral collisions (ν(en)≈10(12) s(-1)). The role of chemical ionization in constructing an adequate theory for the ignition of a gas mixture is discussed. The feasibility of the microwave heating of both the preflame and developed-flame plasma, supplementary to a chemical energy source, is also discussed.

Thermodynamic constraints on the utility of ecological stoichiometry for explaining global biogeochemical patterns

Carbon and nitrogen cycles are coupled through both stoichiometric requirements for microbial biomass and dissimilatory metabolic processes in which microbes catalyse reduction-oxidation reactions. Here, we integrate stoichiometric theory and thermodynamic principles to explain the commonly observed trade-off between high nitrate and high organic carbon concentrations, and the even stronger trade-off between high nitrate and high ammonium concentrations, across a wide range of aquatic ecosystems. Our results suggest these relationships are the emergent properties of both microbial biomass stoichiometry and the availability of terminal electron acceptors. Because elements with multiple oxidation states (i.e. nitrogen, manganese, iron and sulphur) serve as both nutrients and sources of chemical energy in reduced environments, both assimilative demand and dissimilatory uses determine their concentrations across broad spatial gradients. Conceptual and quantitative models that integrate rather than independently examine thermodynamic, stoichiometric and evolutionary controls on biogeochemical cycling are essential for understanding local to global biogeochemical patterns.

Hydrogen production by methane and hydrogen sulphide reaction: Kinetics and modeling study over Mo/La2O3–ZrO2 catalyst

Actually, catalytic steam reforming method is a widely used to produce hydrogen or syngas as the first step for the conversion of methane into liquid fuels through the Fischer-Tropsch synthesis.The reforming of CH4 by H2S can be considered as an alternative route to produce hydrogen from methane. With this process, the removal of H2S in natural gas streams is no longer necessary and sulfur, usually considered as a strong pollutant on liquid fuels in refineries, is used as a reagent in H2S form of hydrodesulphurization processes. This alternative produces hydrogen, a valuable chemical and clean energy source, as the principal product and carbon disulphide as a secondary petrochemical with high commercial value.The open literature concerning the kinetic study of the methane-hydrogen sulphide reaction is very poor. In this research the reaction of CH4 and H2S over zirconia catalyst modified with lanthanum oxide impregnated with molybdenum has been studied in a fixed bed tubular reactor varying the inlet CH4 flow rate over a temperatures range of 1023–1323 K and feed molar ratio CH4:H2S of 1:12. The Langmuir–Hinshelwood theory has been used to analyze kinetic models. Model discrimination has been performed and the kinetic parameters and adsorption constants calculated.Finally, the simulation process of reforming CH4 by H2S has been developed in which separation of the produced hydrogen and no reacted H2S involves absorption through diethanolamine. A tubular reactor from kinetic parameters was dimensioned. Aspen Plus ® 11.1 and Hysys V.8 simulation software was used. Preliminary results showed a high purity H2 can be produced by this route.

Non-equilibrium fractionation of stable carbon isotopes in chemosynthetic mussels

Chemosynthetic bivalves from deep-sea hydrothermal vents exploit the energy derived from chemical compounds, such as methane, sulfide or hydrogen, using symbiotic bacteria that are able to fix inorganic carbon. Available chemical resources in their habitat vary widely at various scales, from the vent field scale to the micro-habitat scale. Parallel to this environmental heterogeneity, Bathymodiolus species are considered to be flexible in their energy acquisition pathways.The goal of this study was to determine whether the isotopic compositions archived in the shells of hydrothermal vent mussels could trace chemical energy sources and their variability over spatial and temporal scales. Two different species (Bathymodiolus azoricus and Bathymodiolus thermophilus) inhabiting three vent fields with contrasted geochemical features on the Mid Atlantic Ridge (MAR; Rainbow and Menez Gwen) and the East Pacific Rise (EPR; 9°47′N), were considered for carbon isotopes and growth rate variation along the shell length. The study revealed that 13C fractionation between shells and seawater is higher than expected from calcite–bicarbonate equilibrium fractionation, suggesting a significant influence of the chemosynthetic pathway on the shell composition. Furthermore, significant differences in δ13Cshell fractionation with respect to seawater are observed between sites and habitats of the two MAR vent fields, suggesting that different chemosynthetic pathway (e.g. methanotrophic and thiotrophic) could lead to variable enrichments of the shell in 13C. Mussels supposed to rely more largely on methanotrophy (at Rainbow where free sulfide is unavailable) display a lower δ13Cshell values than mussels relying also on sulfide-oxidizing symbiosis (at Menez Gwen). Variability in δ13Cshell between habitats, or between individuals within the same assemblage, could thus reflect differences in the symbiosis activity at a micro-habitat scale. These isotopic signatures could provide useful information on the relationships between micro-habitat properties, symbiont activity and shell mineralization.

Structural and Spectroscopic Studies on Electrolytes Containing Novel Salts Dedicated to Lithium-Ion Batteries

Lithium anode an Li-ion batteries are chemical power sources of high energy and power density. In other words, such batteries can be light, small and relatively efficient. Therefore, they can be used in several power-demanding devices, like laptops, tablets, smartphones as well as cameras. Despite of this commercial success, the scientific works oriented on development of these power sources are still conducted. The most important problem, which still needs to be solved, is stability of the battery and battery life length. This is related to the stability of the electrolyte-electrode interfaces.Due to this, the importance of the research on novel salts for batteries' electrolytes grew more and more important. The focus was put on looking for novel lithium salts which dissociate well in aprotic solvents and are electrochemically and thermally stable.In the present study, spectroscopic and structural properties of the solvates of the lithium salts with fluorine-free heteroaromatic anion are researched. The main impact is put on complexes of the salts with dimethyl ethers of ethylene glycol oligomers (glymes) and organic carbonates.Correlation between crystal structures, obtained from X-ray diffraction experiments on the single crystals with vibrational spectroscopy data (FTir and Raman) should make the prediction of the cation-anion-solvent molecule interactions in the liquid systems possible.The discovering and understanding of phenomena related to the organization of such systems in the solid state is crucial for the elaboration of novel electrolytes. Gained knowledge will be helpful in the design of novel compounds with defined properties and in optimization of the working systems.

Chemical Energy Sources Transformations by Remote Experiment

The paper describes the first experience with the set up, functioning and data evaluation of the remote experiment “Energy transformation” accessible via Internet (http://remotelab10.truni.sk) as a part of the e-laboratory at the Department of Physics, Faculty of Education, Trnava University in Trnava, Slovakia. The remote experiment control and data acquisition is based on the system ISES (Internet School Experimental System) and its control program and www page are built using the environment Easy Remote ISES. The main goal of the experiment is the elucidation of the energy transformations of three types of well known energy sources – photovoltaic cell (solar energy to electrical energy), electrolyser (electrical to chemical energy of hydrogen) and fuel cell (chemical energy of hydrogen to electrical energy) and finding optimal regimes for their maximum efficiencies. The perspective of the improvement of the experiment and its exploitation is given

Structural Studies of the Lithium and Sodium Salts with Heteroaromatic, Percyanated Anion

Lithium anode an Li-ion batteries are chemical power sources of high energy and power density. In other words, such batteries can be light, small and relatively efficient. Therefore, they can be used in several power-demanding devices, like laptops, tablets, smartphones as well as cameras. Despite of this commercial success, the scientific works oriented on development of these power sources are still conducted. Novel lithium batteries for special applications (extremely high and low temperatures, long-time-without-charging power sources) are being continuously elaborated. The most important problem, however, is stability of the battery and battery life length. This is related to the stability of the electrolyte-electrode interfaces. Due to the huge demand for power sources from car industry, working out of the sodium and Na-ion batteries (analogs of lithium anode and Li-ion) is one of the biggest challenges for the electrochemists. In case of these batteries, problem of electrode-electrolyte stability (i.e. problem of corrosion of the electrodes) was not solved in the state-of-the art. The formation of SEI of good properties- stable in time and ion-conducting layer formed on the interface of the electrode is still a problem. If such layer was formed, majority of problems related to the construction of sodium-based batteries would be solved. One of the possible approaches which may lead to overcoming of the above-mentioned problems is use of the novel types of the salt. In early 2000s, Armand proposed a novel type of the salts, with five-membered ring consisting of carbon and nitrogen, in which all the carbon atoms are substituted with cyano groups. The architecture of the proposed anion leads to distribution of the charge on all the nitrogen atoms. Moreover, the ion pairing in the lithium or sodium salts of such anions is relatively weak due to fact that cations are “hard” acids and nitrogen atoms are “soft” bases. The nitrogen-rich salt is also interesting due to fact that introduction of the nitrogen to SEI leads to the better properties of this layer. In the recent years several heteroaromatic salts, derivatives of triazole, imidazole and pyrrole were synthesized and their crystallographic and spectral data were published. In the present study we focus on the study of solvates of the salts shown above, and on the influence of the structure of the crystalline complexes on their vibrational spectra. The main impact is put on complexes of the salts with dimethyl ethers of ethylene glycol oligomers (glymes), due to their importance as model systems for poly(ethylene oxide) based electrolytes. Variety of the negatively charged sites available for cation complexation leads to the formation of adducts with different structure, being models for single ions, ionic pairs or aggregates. Also simulations of the formation of the ionic agglomerates in ether-based systems has good support when the presented results are taken into consideration. It is worth to stress out that there is not any electrolyte based on organic carbonates which is stable against material of the anode in the state-of-the-art. Therefore, ethers are one of interesting candidates for solvents dedicated to battery with the sodium-type (metallic Na, Na-ion and similar) anode. What is also important, the compatibility (as well as solubility) of the studied salts with organic carbonates is weak and, due to this, solubility of the studied salts in carbonates is too small to use such solutions as electrolytes in real battery systems produced in the industrial scale.

Methanation catalytic reactor

Storing renewable electricity in a natural gas grid is a new approach for seasonal storage. Using the existing natural gas infrastructure, a chemical energy source (methane) is stored efficiently, distributed and made available for use as required. Thus, the main step in the storage process is CO methanation. Modelling of an isothermal methanation catalytic reactor based on a kinetic scheme was carried out with Aspen plus™ software in a temperature range between 520 and 600 K and a H2/CO molar ratio of 3, in the presence of CO2 and steam. The model was validated by comparing simulation results with experimental ones. The maximum relative error is 10.87%. The effects of temperature, pressure and CO2 addition in feed gas (syngas) on CO conversion and the outlet gas composition were carefully investigated.

A technique for in vivo mapping of myocardial creatine kinase metabolism

ATP derived from the conversion of phosphocreatine to creatine by creatine kinase provides an essential chemical energy source that governs myocardial contraction. Here, we demonstrate that the exchange of amine protons from creatine with protons in bulk water can be exploited to image creatine through chemical exchange saturation transfer (CrEST) in myocardial tissue. We show that CrEST provides about two orders of magnitude higher sensitivity compared to (1)H magnetic resonance spectroscopy. Results of CrEST studies from ex vivo myocardial tissue strongly correlate with results from (1)H and (31)P magnetic resonance spectroscopy and biochemical analysis. We demonstrate the feasibility of CrEST measurement in healthy and infarcted myocardium in animal models in vivo on a 3-T clinical scanner. As proof of principle, we show the conversion of phosphocreatine to creatine by spatiotemporal mapping of creatine changes in the exercised human calf muscle. We also discuss the potential utility of CrEST in studying myocardial disorders.

Optimisation of material and energy exchange in an eco-park network considering three fuel sources

This work represents a quantitative assessment of the eco-park theory and its application to a case involving the manufacture and export of several chemical products in addition to heat and electricity from an eco-industrial park comprised of a number of facilities or ‘nodes’. The eco-industrial network is assessed in terms of environmental impact and profitability relative to existing facilities that do not interact directly with the exchange of material and energy streams amongst the nodes. GAMS software was employed to create the optimisation program with decision variables describing which of the network nodes should be constructed and what their associated production capacities should be in order to optimise an objective function focused on profit and environmental impact. Additionally, utilisation of three different fuels as the primary source of chemical reagents and energy are considered in various scenarios. These fuels are coal and biomass for gasification or a steam-methane reforming process for hydrogen production using natural gas as the fuel. The eco-park network with interacting production nodes is shown to be more profitable than the comparable non-integrated set of facilities and the network exports are produced with lower environmental impact in terms of criteria air contaminants.

21pm2-F1 化学反応を駆動源とする自励振動ゲルポンプの開発

We succeeded in development of a novel gel-pump-embedded microchip. The gel actuator directly converts the chemical energy of the Belousov-Zhabotinsky (BZ) reaction to the mechanical energy. The gel pump generates the adequate force as the micro-pump in the novel microchip system. The gel-pump-embedded microchip requires no electric cord and electric power source. That is because the microchip includes chemical energy source. The microchip does not need connection to the conventional syringe pumps. Therefore, the microchip avoids any contamination.

Metabolic imaging of the human heart: clinical application of magnetic resonance spectroscopy

Cardiovascular MRI has earned its place in the field of clinical cardiac imaging. Regularly used techniques include anatomical imaging, functional imaging, perfusion, and delayed enhancement (DE). Cardiac magnetic resonance spectroscopy...

Starch metabolism in green algae

AbstractStarch plays a central role in the life cycle as one of the principal sources of chemical energy. This polysaccharide accumulates in plastids in green algae and land plants, and both organisms have acquired various enzyme isoforms for each step of the metabolic pathway. Eukaryotic green microalgae present the critical photosynthetic functions as higher plants. However, due to the small size of their genome, gene redundancy is decreased, a feature that makes them an excellent model for investigating the properties of photosynthetic physiology. In the last decade, there has been an increasing demand for starch in many industrial processes, such as food, pharmaceutical, and bioethanol production. Thus, a better understanding of starch biosynthesis, in particular the structure–function relationship and regulatory properties of the enzymes involved in its production may provide a powerful tool for the planning of new strategies to increase plant biomass, as well as to improve the quality and quantity of this polymer.

Cost–Performance Analysis and Optimization of Fuel-Burning Thermoelectric Power Generators

Energy cost analysis and optimization of thermoelectric (TE) power generators burning fossil fuel show a lower initial cost compared with commercialized micro gas turbines but higher operating cost per energy due to moderate efficiency. The quantitative benefit of the thermoelectric system on a price-per-energy ($/J) basis lies in its scalability, especially at a smaller scale (<10 kW), where mechanical thermodynamic systems are inefficient. This study is based on propane as a chemical energy source for combustion. The produced heat generates electric power. Unlike waste heat recovery systems, the maximum power output from the TE generator is not necessarily equal to the economic optimum (lowest $/kWh). The lowest cost is achieved when the TE module is optimized between the maximum power output and the maximum efficiency, dependent on the fuel price and operation time duration. The initial investment ($/W) for TE systems is much lower than for micro gas turbines when considering a low fractional area for the TE elements, e.g., 5% to 10% inside the module. Although the initial cost of the TE system is much less, the micro gas turbine has a lower energy price for longer-term operation due to its higher efficiency. For very long-term operation, operating cost dominates, thus efficiency and material ZT become the key cost factors.

Facts around Mitochondrial Shape, Reorganization and Oocyte Maturation

Mitochondria are a membrane-enclosed organelles found in most eukaryotic cells. Mitochondria are sometimes described as “energy house” because they generate adenosine triphosphate (ATP), which is used as a source of chemical energy. In addition, they are involved in cell signaling, cellular differentiation, cell growth, cell cycle and cell death. However, the exact role of mitochondria during in vitro embryo production technology wasn't fully understood; especially the repositioning of active mitochondria during oocyte maturation, fertilization, and culturing. So, this study aimed to clarify the relationship between oocyte maturation and the repositioning of active mitochondria. It has been found and in contrast to previous reports that repositioning of active mitochondria isn't an utter sign to completion of oocyte maturation. In addition, oocyte mitochondria have fine crystal shape, other than, coarse particles in previous reports.

Trial designs of ultra-thin palladium alloy membrane purifiers for high-density hydrogen production Pt. 2

This two-part article takes a critical look at how various trial designs of palladium alloy membrane systems are being employed to maximise the efficient production of high-density hydrogen – a potentially significant chemical constituent and energy source. In this, the second and final instalment, we look at trial module designs based on composite palladium/palladium alloy membranes, and discuss hydrogen flux, measured permeance, the effect of pressure drop on hydrogen purity, costs of hydrogen purity and recent trends.

Metagenomic evidence for sulfur lithotrophy by Epsilonproteobacteria as the major energy source for primary productivity in a sub-aerial arctic glacial deposit, Borup Fiord Pass

We combined free enenergy calculations and metagenomic analyses of an elemental sulfur (S0) deposit on the surface of Borup Fiord Pass Glacier in the Canadian High Arctic to investigate whether the energy available from different redox reactions in an environment predicts microbial metabolism. Many S, C, Fe, As, Mn, and oxidation reactions were predicted to be energetically feasible in the deposit, and aerobic oxidation of S0 was the most abundant chemical energy source. Small subunit ribosomal RNA (SSU rRNA) gene sequence data showed that the dominant phylotypes were Sulfurovum and Sulfuricurvum, both Epsilonproteobacteria known to be capable of sulfur lithotrophy. Sulfur redox genes were abundant in the metagenome, but sox genes were significantly more abundant than reverse dsr (dissimilatory sulfite reductase)genes. Interestingly, there appeared to be habitable niches that were unoccupied at the depth of genome coverage obtained. Photosynthesis and oxidation should both be energetically favorable, but we found few or no functional genes for oxygenic or anoxygenic photosynthesis, or for oxidation by either oxygen (nitrification) or nitrite (anammox). The free energy, SSU rRNA gene and quantitative functional gene data are all consistent with the hypothesis that sulfur-based chemolithoautotrophy by Epsilonproteobacteria (Sulfurovum and Sulfuricurvum) is the main form of primary productivity at this site, instead of photosynthesis. This is despite the presence of 24-h sunlight, and the fact that photosynthesis is not known to be inhibited by any of the environmental conditions present. This is the first time that Sulfurovum and Sulfuricurvum have been shown to dominate a sub-aerial environment, rather than anoxic or sulfidic settings. We also found that Flavobacteria dominate the surface of the sulfur deposits. We hypothesize that this aerobic heterotroph uses enough oxygen to create a microoxic environment in the sulfur below, where the Epsilonproteobacteria can flourish.

Phylogenetic diversity and functional gene patterns of sulfur-oxidizing subseafloor Epsilonproteobacteria in diffuse hydrothermal vent fluids

Microorganisms throughout the dark ocean use reduced sulfur compounds for chemolithoautotrophy. In many deep-sea hydrothermal vents, sulfide oxidation is quantitatively the most important chemical energy source for microbial metabolism both at and beneath the seafloor. In this study, the presence and activity of vent endemic Epsilonproteobacteria was examined in six low-temperature diffuse vents over a range of geochemical gradients from Axial Seamount, a deep-sea volcano in the Northeast Pacific. PCR primers were developed and applied to target the sulfur oxidation soxB gene of Epsilonproteobacteria. soxB genes belonging to the genera Sulfurimonas and Sulfurovum are both present and expressed at most diffuse vent sites, but not in background seawater. Although Sulfurovum-like soxB genes were detected in all fluid samples, the RNA profiles were nearly identical among the vents and suggest that Sulfurimonas-like species are the primary Epsilonproteobacteria responsible for actively oxidizing sulfur via the Sox pathway at each vent. Community patterns of subseafloor Epsilonproteobacteria 16S rRNA genes were best matched to methane concentrations in vent fluids, as well as individual vent locations, indicating that both geochemistry and geographical isolation play a role in structuring subseafloor microbial populations. The data show that in the subseafloor at Axial Seamount, Epsilonproteobacteria are expressing the soxB gene and that microbial patterns in community distribution are linked to both vent location and chemistry.