Miracle-dz/UniFAR-FTUs huggingface dataset:
The reversibility of the reaction CaCO3 ⇄ CaO+CO2

The reversibility of the reaction CaCO3 ⇌ CaO+CO2 has been examined through a large number of cycles (up to 40), mainly at 866 °C. The decomposition to the oxide is always 100% but the reactivity of the oxide so formed to carbon dioxide falls off markedly after a rapid initial reaction. There is a large increase in surface area on going from the non-porous calcium carbonate to the oxide and this is due to the formation of pores, mostly very small (< 4 nm). The fast component of the back reaction is a surface reaction and the subsequent slow reaction is controlled by the slow diffusion of carbon dioxide through the newly formed carbonate layer. The reversibility of the reaction decreases with the number of cycles, rapidly at first and then more slowly: the first effect is probably due to loss of pore volume in the oxide and the second to sintering of the carbonate.
Switchgrass Response to Harvest Frequency and Time and Rate of Applied Nitrogen

Abstract Switchgrass (Panicum virgatum L.) is currently being evaluated as a raw material for producing fuel, chemicals, and electricity. Switchgrass biomass is bound by the growing environment that includes fertility. More information is needed on sustainable switchgrass production as influenced by nitrogen fertility and harvest management. Field experiments were initiated at Chickasha and Perkins, OK in 1996 and 1998, respectively to evaluate switchgrass response to applied nitrogen (N) at rates of 0, 112, 224, 448, and 896 kg ha−1. In addition, harvest frequency and time of N application were evaluated. Yield maximums and the greatest N, potassium (K), phosphorus (P), and sulfur (S) uptake values were achieved with 448 kg N ha−1 applied all in April and harvested three times. In fact, harvest frequency was the most important factor affecting yields over the course of these studies with average dry matter yields of 16.3, 14.7, and 12.9 Mg ha−1 yr−1 for three, two, and one harvest yr−1, respectively. No significant change in soil organic carbon was detected over time. Although dry matter yields were found to decline with time, total N uptake did not. Forage N concentration was found to be greater in later years, thus increasing production costs. While yields were highest (18.0 Mg ha−1) with 448 kg N ha−1 applied all in April and three harvests, applying 0 N and harvesting three times produced almost as much total biomass (16.9 Mg ha−1). This limited response to N is possibly explained by the evolution of switchgrass under low N conditions. Increasing forage concentrations of K, magnesium (Mg), P, and S were noted with increasing yields, indicating a potential for response to these nutrients. #Contribution from the Oklahoma Agricultural Experiment Station.
Brain-scale emergence of slow-wave synchrony and highly responsive asynchronous states based on biologically realistic population models simulated in The Virtual Brain

Understanding the many facets of the organization of brain dynamics at large scales remains largely unexplored. Here, we construct a brain-wide model based on recent progress in biologically-realistic population models obtained using mean-field techniques. We use The Virtual Brain (TVB) as a simulation platform and incorporate mean-field models of networks of Adaptive Exponential (AdEx) integrate-and-fire neurons. Such models can capture the main intrinsic firing properties of central neurons, such as adaptation, and also include the typical kinetics of postsynaptic conductances. We hypothesize that such features are important to a biologically realistic simulation of brain dynamics. The resulting “TVB-AdEx” model is shown here to generate two fundamental dynamical states, asynchronous-irregular (AI) and Up-Down states, which correspond to the asynchronous and synchronized dynamics of wakefulness and slow-wave sleep, respectively. The synchrony of slow waves appear as an emergent property at large scales, and reproduce the very different patterns of functional connectivity found in slow-waves compared to asynchronous states. Next, we simulated experiments with transcranial magnetic stimulation (TMS) during asynchronous and slow-wave states, and show that, like in experimental data, the effect of the stimulation greatly depends on the activity state. During slow waves, the response is strong but remains local, in contrast with asynchronous states, where the response is weaker but propagates across brain areas. To compare more quantitatively with wake and slow-wave sleep states, we compute the perturbational complexity index and show that it matches the value estimated from TMS experiments. We conclude that the TVB-AdEx model replicates some of the properties of synchrony and responsiveness seen in the human brain, and is a promising tool to study spontaneous and evoked large-scale dynamics in the normal, anesthetized or pathological brain.
Makro- und Mikrosymptome des Zinkmangels bei höheren Pflanzen

Macro- and Microsymptoms of Zinc Deficiency in Higher Plants The development of zinc deficiency symptoms was studied in eight different plant species grown under controlled experimental conditions in soilless sulture. The following results were obtained. One symptom of zinc deficiency was found to be the development of a violet to red colouring matter which first appeared in the form of small dots or as spots of discolouration which later covered the entire leaf. This discolouration was found primarily in young but already completely developed leaves. Here, the symptoms started to devlop in single cells. Further symptoms of zinc deficiency were observed to be a retarded growth, short internodes, small leaves and a very poor formation of roots.
Phase Behavior of Some Nonionics: Interfacial Tension and HLB at Optimum Conditions

Abstract At optimum phase behavior, the hydrophile-lipophile balance (HLBOPB) values were determined for different nonionics and nonionic binary mixtures. The molar concentration of surfactant, in all the investigated systems, was kept constant at 0.04 M/L aqueous phase in presence of 0.5 wt% tetraethylene glycol as co-surfactant and 1.0 wt% NaCl. n-Alkanes, from hexane to hexadecane, were used as oil phases. All experiments were carried out at 25°C using water oil ratio, 4:1. The study reveals that the IFTOPB is in inverse proportion to HLBOPB, the lower the IFTOPB, the higher the HLBOPB values for each set of the investigated nonionics. When IFTOPB was plotted against the molecular weight of the investigated nonionic mixtures at a different oil phase alkane carbon number, two linear relations had been developed: the first for the monoalkylated and the second for the dialkylated phenol ethoxylate binary mixtures.
Effect of Peer Collaboration Learning Strategy on Students’ Achievement in Basic Science in Makurdi Local Government of Benue State

This study examined the effects of peer collaboration instructional strategy on students’ achievement in basic science among Upper Basic 2 in Makurdi Local Government Area of Benue State. The study employed non-equivalent group pre-test-post-test quasi experimental design. The population of the study was 638 upper basic school levels. The sample for this study was 128 students from six co-educational schools within Makurdi Local Government Area of Benue State. Two research questions and two hypotheses guided the study. The instrument used for data collection was Basic Science Achievement Test (BSAT), and was trial tested using Kuder-Richardson (K-R, 20) formula to determine the reliability coefficient of BSAT which was found to be 0.99. Descriptive statistics of means and standard deviation were used to answer all the research questions and inferential statistics of Analysis of Covariance (ANCOVA) was used to test all the hypotheses at 0.05 significant level. The results of the study showed that, Peer Collaboration Learning Strategy enhanced students’ achievement in Basic Science better than Demonstration method. There is a significant difference between the mean achievement scores of students taught basic science using peer collaborative learning strategy and those taught using demonstration method. There was no significant difference between the mean achievement scores of male and female students taught basic science using peer-collaborative learning strategy. Basic science teachers should not only use peer collaborative strategy to teach the students the subject matter but should also allow them to interact with one another, so that they (students) can take charge of how they can learn. This can foster confidence in the students and enhance their achievement in basic science.
IR‐spectroscopic study of isotope effects on the NH/ND‐stretching bands of meso‐tetraphenylporphine and vibrational hydrogen tunneling

The IR spectra of meso‐tetraphenylporphine (TPP) dissolved in CCl4 have been measured in the NH and ND stretching band region as a function of isotopic substitution using a newly constructed vacuum IR cell. Thus, it was possible for the first time to localize the NH and ND stretching bands of TPP–HD, which are characterized by the wave numbers 3335 and 2493 cm−1. TPP–H2 and TPP–D2 were found to absorb at lower frequencies, namely 3318 and 2482 cm−1. The observation of this band shift allows one to identify the observed NH and ND stretching bands in TPP–H2 and TPP–D2. They arise from antisymmetric stretching vibrations, the symmetric bands being forbidden in the IR spectra. NH/ND stretching bandwidths of the order of 20 cm−1 were observed, which is unusually small for proton transfer systems. This observation further confirms our previous conclusions from the primary HH/HD/DD kinetic isotope effects on the tautomerism in this molecule, namely that the motion of the hydrogen atoms takes place in a coupled m.
CALCIUM: ALUMINIUM EXCHANGE EQUILIBRIA IN CLAY MINERALS AND ACID SOILS1

Summary Exchange reactions between 0.0in AlCl3 solutions of different pH and Ca-saturated montmorillonite, vermiculite, illite, and soils from the Park Grass Experiment at Rothamsted and the Deerpark Experiment, Wexford, Ireland, showed that Al3+ and Al(OH)2+ were adsorbed from solutions of pH > 4.0 and Al3+ and H+ from solutions of pH < 3.0. When Al was adsorbed, the cation exchange capacity of Ca-saturated soils and clays increased. Conventional Ca: Al exchange isotherms showed that Al3+ was strongly preferred to Ca2+ on all soils and clays. The equilibrium constant for Ca: Al exchange, K, was identical for soils before and after oxidizing their organic matter and did not vary, for any exchanger, with Al-saturation or the initial pH of the AlCl3 solution. This proved the validity of the procedure used for calculating exchangeable Al3+. K values for Ca:Al exchange favoured Al3+ in the order: vermiculite > Park Grass soil > Deerpark soil > illite > montmorillonite. The influence of surface-charge densities of the clay minerals on this order is discussed and a method proposed and tested for calculating the K value of a soil from its mineralogical composition.
The lattice expansion of iron

The lattice spacings of high-purity iron have been measured accurately between 20 and 1502°C. The results, together with previous low-temperature data, give data between the absolute zero and the melting-point (1534°C). The thermal expansion of the lattice and of bulk metal are in good agreement over the temperature range for which the latter has been studied accurately. At the A2 point, there is no discontinuity in the lattice spacing. In contrast to the work of some previous investigators, we have found no observable difference between the coefficients of expansion of the lattice immediately above and below the A2 point, and the results suggest that the forces responsible for ferromagnetism do not affect the interatomic distances by more than 1 part in 10000. At the A3 point, the α→γ transformation is accompanied by an increase in the interatomic distance which, when expressed as a percentage change, is slightly less than the decrease in interatomic distance during the γ→δ change at the A4 point. The change in bond length calculated by the Pauling equation for the change (f. c. c.⇌b. c. c.) lies between the observed values for the A3 and A 4 points, and the accuracy of the equation is confirmed.
Theory of transport in liquid metals. I. Calculation of self‐diffusion coefficients

An approach is presented for the theoretical calculation of self‐diffusion coefficients of liquid metals. The basic assumption is that the self‐diffusion coefficient of a liquid metal is equal to that of an appropriate hard sphere fluid. The hard sphere diameter is dependent upon temperature, and a method is developed for estimating this temperature dependence by exploring the relationship between the diameter and the interatomic potential energy function of the liquid metal. The theory gives accurate results for the magnitude and temperature dependence of the self‐diffusion coefficient for many liquid metals. In addition, the physical basis for the theory is consistent with what has been learned about the liquid state from molecular dynamics calculations.
On the interaction between the 5s-p and 4d-p channels in Sr I

A two-channel quantum defect model is applied to analyse the strongly perturbed principal absorption series of Sr near threshold. Experimental data in the discrete and in the autoionization region are expressed in terms of five parameters: two eigenquantum defects μα, one transformation angle θ, and two dipole matrix elements Dα. Values of the parameters, obtained by fitting the experimental data, provide information on the mixing coefficients of the levels and oscillator strength as well as on photoabsorption cross sections in the autoionization region. The two-channel model is sufficient to describe the discrete spectrum. Discrepancies show up between theory and experiment in the autoionization region because of opening up of additional channels above the first ionization threshold.
Sake and Beer Spoilage Lactic Acid Bacteria — A Review

: Japanese rice wine, sake, is a traditional alcoholic beverage in Japan. Similar to the case with beer, sake is known to be microbiologically stable and most microorganisms fail to grow in sake. This is principally due to its high ethanol concentration that reaches approximately 20% (v/v) in undiluted sake products and 15% (v/v) in finished products. Despite the high level of ethanol content, spoilage incidents occasionally occur in sake, due to the presence of highly ethanol-tolerant lactobacilli, known as hiochi-bacteria. Hiochi-bacteria are generally composed of two groups of lactobacilli, hiochi-lactobacilli and true hiochi-bacilli. The former group of lactobacilli is less ethanol-and heat-tolerant, and therefore rarely poses a problem to sake products. In contrast, the true hiochi-bacilli exhibit extraordinarily high ethanol tolerance and cause spoilage incidents in sake, conferring acidity and off-flavors, such as diacetyl, in spoiled products. From a taxonomic standpoint, the true hiochi-bacilli mainly consist of two Lactobacillus species, L. fructivorans and L. homohiochi. The strains of true hiochi-bacilli prefer sake-like environments, and the presence of ethanol and mevalonic acid, in combination with low pH milieu, is essential or stimulatory for the growth of these bacteria. Interestingly, the type strain of L. fructivorans does not show such characteristics, suggesting the true hiochi-bacilli are profoundly adapted to sake environments. Although beer spoilage lactic acid bacteria do not have close taxonomic relationships with true hiochi-bacilli, there are striking similarities between these two groups of spoilage lactic acid bacteria. In this review, unique features of sake and beer spoilage lactic acid bacteria are discussed in comparative terms.
Observation of the transition of operating regions in a low-pressure inductively coupled oxygen plasma by Langmuir probe measurement and optical emission spectroscopy

In inductively coupled low-pressure oxygen plasmas, planar Langmuir probes were used to determine the variation of the plasma parameters (positive and negative ion densities, electron density, electron temperature) with applied pressure (1-40 mTorr) and power (1-800 W). Simultaneous optical emission spectra were obtained. The relative abundance of the species was estimated from the intensities of the two spectral lines from excited oxygen atoms and molecular oxygen ions. In conjunction with the Langmuir probe data, the scaling behaviours of the charged and neutral species were investigated. A change of scaling behaviour in charged and neutral species densities which was due to the transition from the ion-flux-loss-dominated region to the recombination-loss-dominated region was observed by Langmuir probe measurement and optical emission spectroscopy.
Strong H2 Binding and Selective Gas Adsorption within the Microporous Coordination Solid Mg3(O2C-C10H6-CO2)3

The synthesis of Mg3(NDC)3(DEF)4 (NDC = 2,6-naphthalenedicarboxylate, DEF = N,N-diethylformamide, 1), the first porous metal−organic framework solid incorporating Mg2+ ions, is reported. Its structure consists of linear Mg3 units linked via NDC bridges to form a three-dimensional framework, featuring one-dimensional channels filled with DEF molecules. Significantly, its framework is fully analogous to that observed within Zn3(NDC)3(CH3OH)2·2DMF·H2O (2), demonstrating that Mg2+ ions can directly substitute for the heavier Zn2+ ions. Compound 1 is readily desolvated by heating at 190 °C to give the microporous solid Mg3(NDC)3, exhibiting a BET surface area of 190 m2/g. Adsorption isotherms measured at 77 and 87 K indicate high H2 adsorption enthalpies in the range 7.0−9.5 kJ/mol, depending on the degree of loading. In addition, the material displays selective adsorption of H2 or O2 over N2 or CO, suggesting possible applications in gas separation technologies.
Adsorptive Separation and Recovery of Organic Compounds from Purified Terephthalic Acid Plant Effluent

Several organic impurities formed in the p-xylene oxidation process for manufacture of terephthalic acid are carried into the aqueous effluent from the crystallization section of PTA plant of crystallizers for purified terephthalic acid (PTA). These compounds impose a burden on the effluent treatment plant. Due to the presence of these impurities the recycle of aqueous effluent from crystallization section of PTA plant to the PTA crystallizer is not possible. The aim of this study is to check the feasibility of removal of these organic impurities from the aqueous effluent from crystallization section of PTA plant by adsorption on polymeric resins so that the aqueous effluent from crystallization section of PTA plant can be recycled resulting in significant saving of process water. Aqueous effluent from crystallization section of PTA plant was characterized and single solute and multisolute adsorption equilibria of the compounds present were determined for a variety of polymeric adsorbents. Column breakthrough study has shown that the components can be removed and recovered from the aqueous effluent from the crystallization section of PTA plant by adsorption.
Spray pyrolysis deposition of thin films

Ternary compound thin films have been prepared on Pyrex glass substrates by the spray pyrolysis process using tin chloride and n, n-dimethylthiourea as starting materials. The depositions were carried out at a substrate temperature of . The identification of the phase was achieved by means of x-ray diffraction measurements. The optical reflectance and transmittance of the prepared films were used to obtain the variation of the refractive index and the extinction coefficient as a function of the wavelength. These calculated values were used to find the absorption coefficient and the optical bandgap and gave . From measurements of the conductance as a function of , a dark activation energy was determined with a value of 1.02 eV.
Factors Controlling the Geochemical Partitioning of Trace Metals in Estuarine Sediments

The geochemical partitioning of trace metals in sediments is of great importance in risk assessment and remedial investigation. Selected factors that may control the partitioning behavior of Cu, Pb and Zn in non-sulfidic, estuarine sediments were examined with the use of combined sorption curve—sequential extraction analysis. This approach, which has not been previously used to examine estuarine sediments, allowed determination of sorption parameters for Cu, Pb and Zn partitioning to individual geochemical fractions. Partitioning behavior in sulfidic sediments was also determined by sequentially extracting Cu, Pb, and Zn from synthetic sulfide minerals and from natural sediment and pure quartz sand after spiking with acid-volatile sulfide (AVS). Trace metal sorption to the “carbonate” fraction (pH 5, NaOAc extraction) increased with metal loading due to saturation of sorption sites associated with the “Fe-oxide” (NH2OH·HCl extraction) and “organic” (H2O2 extraction) fractions in non-sulfidic sediments. Freundlich parameters describing sorption to the “Fe-oxide” and “organic” fractions were controlled by the sediment Fe-oxide and organic carbon content, respectively. Sequential extraction of Cu from pure CuS, AVS-spiked sediment and AVS-spiked quartz sand showed that AVS-bound Cu was quantitatively recovered in association with the “organic” fraction. However, some AVS-bound Pb and Zn were recovered by the NH2OH·HCl step (which has been previously interpreted as “Fe-oxide” bound metals) in the sequential extraction procedure used in this study. This indicates that the sequential extraction of Pb and Zn in sulfidic sediments may lead to AVS-bound metals being mistaken as Fe-oxide bound species. Caution should therefore be exercised when interpreting sequential extraction results for Pb and Zn in anoxic sediments.
Muscle Architecture and its Relationship to Muscle Circulation

Muscle contraction mechanically changes vessel geometry and consequently muscle circulation. Lengthening of muscle fiber straightens capillary tortuosity and further increase in muscle fiber length reduces blood flow by extending the capillary while reducing its diameter. The direction of capillary to the fiber long axis will modify the extent of capillary lumen diameter change due to lengthening muscle fiber. During passive stretching in human subjects, the relationship between changes in blood volume (determined by near-infrared spectroscopy: NIRS) and fascicle length differed among the three heads of triceps surae muscles with different fascicle length and pennation angle. Muscle thickness, muscle curvature, and muscle fascicle angle are potential determinants of intramuscular pressure during muscle contraction. Muscle circulation is impeded more in short bulging muscles with great curvature of fibers than in long slender muscles with less curvature. The different response of circulatory parameters across the synergist muscles in the calf and heterogeneity of muscle circulation in the same muscle were observed, partly due to the difference in the pennation angle of the muscle fascicle. The muscle architecture will influence venous outflow by changing the muscle pumping action. This is possibly an indirect way of modifying vasodilation due to difference in muscle architecture.