Spectroscopic identification of a novel catalytic reaction of potassium and atomic hydrogen and the hydride ion product

From a solution of a Schrödinger-type wave equation with a nonradiative boundary condition based on Maxwell's equations, Mills predicts that atomic hydrogen may undergo a catalytic reaction with certain atomized elements and ions which singly or multiply ionize at integer multiples of the potential energy of atomic hydrogen, $\text{27.2}\text{eV}\text{(m×27.2}\text{eV}$, wherein m is an integer). The reaction involves a nonradiative energy transfer to form a hydrogen atom that is lower in energy than unreacted atomic hydrogen with the release of energy. One such atomic catalytic system involves potassium atoms. The first, second, and third ionization energies of potassium are 4.34066, 31.63, and $\text{45.806}\text{eV}$, respectively. The triple ionization reaction of K to K³⁺, then, has a net enthalpy of reaction of $\text{81.7766}\text{eV}$, which is equivalent to $\text{3×27.2}\text{eV}$. Intense extreme ultraviolet (EUV) emission was observed from incandescently heated atomic hydrogen and the atomized potassium catalyst that generated an anomalous plasma at low temperatures (e.g. $\text{≈10}{}^3\text{K}$) and an extraordinary low field strength of about 1–$\text{2}\text{V/cm}$. No emission was observed with potassium or hydrogen alone or when sodium replaced potassium with hydrogen. Emission was observed from K³⁺ that confirmed the resonant nonradiative energy transfer of $\text{3×27.2}\text{eV}$ from atomic hydrogen to atomic potassium. The catalysis product, a lower-energy hydrogen atom, was predicted to be a highly reactive intermediate which further reacts to form a novel hydride ion. The predicted hydride ion of hydrogen catalysis by atomic potassium is the hydride ion H⁻(1/4). This ion was observed spectroscopically at $\text{110}\text{nm}$ corresponding to its predicted binding energy of $\text{11.2}\text{eV}$.     

Hydrogen absorption and desorption kinetics of Ag–Mg–Ni alloys

The hydrogen absorption/desorption (A/D) kinetics of hydrogen storage alloys Mg_2−xAg_xNi (x=0.05, 0.1) prepared by hydriding combustion synthesis in two-phase (α–β) region in the temperature range of 523–$\text{573}\text{K}$ have been investigated. The hydriding/dehydriding (H/D) reaction rate constants were extracted from the time-dependent A/D curves. The obtained hydrogen A/D kinetic curves were fitted using various rate equations to reveal the mechanism of the H/D processes. The relationships of rate constant with temperature were established. It was found that the three-dimensional diffusion process dominates the hydrogen A/D. The apparent activation energies of 63±5 and $\text{61±7}\text{kJ/mol}\text{H}{}_2$ in Mg_1.95Ag_0.05Ni alloy and $\text{52±2}\text{kJ/mol}\text{H}{}_2$ and of $\text{50±2}\text{kJ/mol}\text{H}{}_2$ in Mg_1.9Ag_0.1Ni alloy were found for the H/D processes in two-phase (α–β) coexistence region from 523 to $\text{573}\text{K}$, respectively. With the increasing content of Ag in Ag–Mg–Ni alloys, the apparent energy was decreased and the reaction rate was faster. It is reasonable to explain that the hydriding kinetics of Mg₂Ni was improved by adding Ag.     

Growing stock-based forest biomass estimate for India

The total standing biomass (including above ground and below ground) in Indian forests for the year 1992–93 was estimated using information on state and union-territory field inventory based growing stock volume and the corresponding area under three different crown density classes (very dense forests with crown cover 70 percent and above, dense forest with crown cover 40 percent but <70 percent and open forests with crown cover between 10 and 40 percent) grouped under four major forest categories (hardwood, spruce-fir, pine and bamboo) by Forest Survey of India. The growing stock volume was converted to total biomass using biomass expansion factors as function of growing stock volume density. The average growing stock volume density in Indian forests for the study year 1992–93 was $\text{74.42}\text{m}{}^3\text{ha}{}^{\mathrm{-1}}$ but it varied amongst states, with a range of $\text{7.1}\text{m}{}^3\text{ha}{}^{\mathrm{-1}}$ in Punjab to $\text{224.5}\text{m}{}^3\text{ha}{}^{\mathrm{-1}}$ in Jammu and Kashmir. The total standing biomass (above ground and below ground) was estimated as $\text{8683.7}\text{Mt}\text{(}\text{Mt}\text{=10}{}^{12}\text{g}\text{)}$. The aboveground and belowground biomass was estimated as 6865.1 and $\text{1818.7}\text{Mt}$, contributing 79 and 21 percent to the total biomass, respectively. The mean biomass density in Indian forests was estimated as $\text{135.6}\text{t}\text{ha}{}^{\mathrm{-1}}$ and amongst the states it varied from $\text{27.4}\text{t}\text{ha}{}^{\mathrm{-1}}$ in Punjab to $\text{251.8}\text{t}\text{ha}{}^{\mathrm{-1}}$ in Jammu and Kashmir, respectively. The estimates have been compared with previous studies, which had estimated biomass in the range of 4400–$\text{8700}\text{Mt}$ for the corresponding period. Our results are an improvement over previous estimates as these incorporate biomass expansion factors which relate wood volume to biomass as a function of growing stock volume density, four forest types and three crown density classes of Indian forests. These improved biomass estimates are crucial to assess the total C pool of forests and further for use as inputs to models to estimate net C flux to atmosphere from Indian forests due to deforestation and landuse changes.     

Yield improvements through modification of planting density and harvest frequency in short rotation coppice Salix spp.—1. Yield response in two morphologically diverse varieties

An experiment comparing the dry matter yield of intensively managed short rotation coppice (SRC) under factorial combinations of two plant varieties (S. viminalis cv. Jorunn and S. x dasyclados), five planting densities (10,000–$\text{111,000}\text{plants}\text{ha}{}^{\mathrm{-1}}$) and two harvesting frequencies is reported. Data are presented from the first biennial and triennial harvest cycles at two sites (East Anglia and Warwickshire, UK) planted in spring 1996 and flailed in autumn 1996.Higher annual yields were attainable by more intensive packing of plants combined with more frequent harvesting. With S. viminalis cv. Jorunn, yield increased by 34% between the lowest and highest planting densities. Biennial harvesting increased yield compared with triennial harvests. S. viminalis, on average, yielded $\text{2.7}\text{t}\text{ha}{}^{\mathrm{-1}}\text{yr}{}^{\mathrm{-1}}$ more than S. x dasyclados, with peak yields of $\text{11.4}\text{t}\text{ha}{}^{\mathrm{-1}}\text{yr}{}^{\mathrm{-1}}$. Significant differences in yield between sites were noted, with an average of $\text{1}\text{t}\text{ha}{}^{\mathrm{-1}}\text{yr}{}^{\mathrm{-1}}$ benefit on a mineral soil compared with a peaty loam. There were no statistically significant interactions in the data.Biennial plots reached peak heights of 254–$\text{297}\text{cm}$ (S. viminalis) and 239–$\text{273}\text{cm}$ (S. x dasyclados) in 1998. Peak heights of triennial plots (achieved in 1999) were 401–$\text{515}\text{cm}$ (S. viminalis) and 316–$\text{420}\text{cm}$ (S. x dasyclados). There was a gradual increase in height through the three years and a non-significant trend towards decreased height with increasing planting density at the ends of the growing seasons. Both varieties demonstrated phenotypic plasticity, with individual plant weight and stem number decreasing as a function of increasing density.A range of parameters including stem width reduction, stem mortality and plant mortality were seen to vary. The population of primary stems was found to increase up to the time of canopy closure, on a per plant basis and per unit ground area basis. After this time, competition for light resulted in self-thinning of stems through until final harvest for S. dasyclados but not S. viminalis. Stem numbers per plant, recorded after leaf fall, showed different responses between both harvesting frequency and variety. With S. viminalis, stem numbers remained constant after cut back for up to $\text{2}\text{yr}$, but increased rapidly as a result of a harvest after $\text{2}\text{yr}$. With S. x dasyclados, a similar regrowth of stems was observed after a 2-yr harvest. Prior to the harvest, stem numbers per plant decreased steadily for 2 of the $\text{3}\text{yr}$ depending on harvest cycle. After $\text{3}\text{yr}$ stem populations with S. x dasyclados were also decreasing.The degree to which non-destructive measurements could be used to (a) determine annual increment and (b) be used to predict eventual yield was examined. Cylindrical volume was the only growth measurement that enabled a reasonable fit between crop morphology and final yield to be made. The relationship was found to be a good fit and the fit improved with a longer harvest interval. Regression equations were not significantly different between sample sites but were significantly different between both variety (P<0.001) and harvest interval (P<0.05).In summary, we deduce that modern varieties of S. viminalis such as Jorunn, are more suited to higher planting density and intensive harvesting, due to more erect growth reducing intra-specific competition at high planting densities.     

Hydrogen production by Clostridium thermolacticum during continuous fermentation of lactose

In the production of acetate by Clostridium thermolacticum growing on lactose, considerable amounts of hydrogen were generated. Lactose available in large amounts from milk permeate, a wastestream of the dairy industry, appears to be a valuable substrate for cheap production of biohydrogen.In this study, continuous cultivation of C. thermolacticum was carried out in a bioreactor, under anaerobic thermophilic conditions, on minimal medium containing $\text{10}\text{g}\text{l}{}^{\mathrm{-1}}$ lactose. Different dilution rates and pH were tested.C. thermolacticum growing on lactose produced acetate, ethanol and lactate in the liquid phase. For all conditions tested, hydrogen was the main product in the gas phase. Hydrogen specific production higher than $\text{5}\text{mmol}$ H₂ ($\text{g}\text{cell}\text{)}{}^{\mathrm{-1}}\text{h}{}^{\mathrm{-1}}$ was obtained. By operating this fermentation at high-dilution rate and alkaline pH, the hydrogen content in the gas phase was maximized.     

The effect of Mn substitution for Ni on the structural and electrochemical properties of La0.7Mg0.3Ni2.55−xCo0.45Mnx hydrogen storage electrode alloys

The structures, hydrogen storage property and electrochemical properties of the $\text{La}{}_{0.7}\text{Mg}{}_{0.3}\text{Ni}{}_{\mathrm{2.55-x}}\text{Co}{}_{0.45}\text{Mn}{}_{\mathrm{x}}\text{(x=0.0,0.1,0.2,0.3,0.4,0.5)}$ electrode alloys has been studied systematically. It can be found that, by X-ray powder diffraction, the alloys are all consisted of the (La,Mg)Ni₃ phase and the LaNi₅ phase, and the lattice parameters and cell volumes of both the (La,Mg)Ni₃ phase and the LaNi₅ phase increase with increasing Mn content in alloys. The P–C isotherms curves indicate that the hydrogen storage capacity first increases and then decreases with increasing x, and the equilibrium pressure decreases. The electrochemical measurements show that the maximum discharge capacity increases from $\text{342.6}\text{(x=0.0)}$ to $\text{368.9}\text{mA}\text{h}\text{/}\text{g}\text{(x=0.3)}$ and then decreases to $\text{333.5}\text{mA}\text{h}\text{/}\text{g}\text{(x=0.5)}$. For the discharge current density of $\text{1000}\text{mA}\text{/}\text{g}$, the high rate dischargeability (HRD) of the alloy electrodes increases from 55.8% (x=0.0) to 72.3% (x=0.4) and then decreases to 70.0% (x=0.5). Moreover, according to the electrochemical impedance spectroscopy, linear polarization and anodic polarization measurements, the exchange current density I₀ and the limiting current density I_L of the alloy electrodes also all increase first and then decrease with increasing Mn content in alloys.     

Temperature-dependent state of hydrogen molecules within the nanopore of multi-walled carbon nanotubes

In observation of the state of hydrogen molecules within the carbon nanopore, the excess adsorption amounts of hydrogen on the multi-walled carbon nanotubes (MWCNTs) were measured at equilibrium pressure–temperatures from 0.1 to $\text{12.3}\text{MPa}$ and 123 to $\text{310}\text{K}$. The principles of thermodynamic equilibrium and a higher order Virial adsorption coefficient were applied to determining the maximum surface coverage of hydrogen molecules on the adsorbent surface. The thermodynamic equilibrium-based adsorption model was linearized to estimate the interaction energy among the adsorbed hydrogen molecules at each adsorption equilibrium state. The results demonstrate that the interaction energies among adsorbed hydrogen molecules are positive in the lower temperature region $\text{(<200}\text{K}\text{)}$ and reach the maximum value around a temperature from 160 to $\text{180}\text{K}$. However, it will gradually be negative when the temperature is approaching $\text{230}\text{K}$. In other words, the confined hydrogen molecules repulse each other in the low-temperature environment while they attract each other at the ambient temperature. It implies that the dissociativeness of hydrogen occurred in the experimental pressure–temperature range, and it is also suggested that the temperature between 160 and $\text{180}\text{K}$ could be a preferable condition to make full use of physical and chemical adsorption of hydrogen molecules on the adsorbent.