Miracle-dz/UniFAR-FTUs huggingface dataset:
Carrier distributions in long wavelength quantum dot laser diodes

In this thesis I have produced results to show how carriers populate electronic states of InAs quantum dot (QD) laser diodes which operate near 1.3um, especially those which incorporate tunnel injection. I used the segmented contact method to produce modal absorption, modal gain, spontaneous emission and population inversion spectra as a function of photon energy. The spontaneous emission spectra for a high performance QD structure showed an increased population of the higher energy QD states than the tunnel injection structure. Analysis of the carrier distribution within the high performance QD structure revealed that the population of the QD states can be described by Fermi- Dirac statistics (thermally distributed) at 300K. As the temperature is lowered the electron distribution becomes clearly non-thermal, with clear regions of high inversion seen in the lower energy QD states. The higher inversion can be attributed to a reduced population of wetting layer states and as the temperature is lowered it becomes less likely for carriers to excite out of the dot states and thermally redistribute throughout the ensemble. The tunnelling injection structure was shown to exhibit unique features in its carrier distribution as compared to the high performance structure. At 300K the carrier distribution function is populated to thermal levels over energy ranges corresponding to a subset of the QD ground and first excited states. Between these energy ranges there is a region of under populated states shown by a region of low inversion. This suggests dots of a particular size within the ensemble are preferentially populated by the resonant tunnelling process. This results in a reduced spectral broadening of the emission from the QD ensemble. At higher temperature the selective population can still be observed, however it is less pronounced, presumably due to more efficient thermal distribution of electrons at higher temperature
Business performance of start-Ups in agriculture - A case study

The present study analysed the business performance of Green Grow Nutrients Pvt. Ltd., an agriculture start-up company based in Bengaluru city. The business performance and growth rates were analysed by using financial ratios and compound annual growth rate. The marketing strategies was also analysed by using percentage analysis and Garrett’s ranking technique. The study revealed that all the liquidity ratios except quick ratio were the highest for the year 2017-18 which indicates that the company can meet its current debt obligations. The study also reveals that the company registered an impressive performance with respect to procurement and sales. (CAGR of 17 and 16 percent respectively).
Aqueous Methane in Slit-Shaped Silica Nanopores: High Solubility and Traces of Hydrates

Equilibrium molecular dynamic simulations were employed to investigate the methane solubility in water confined between two parallel silica surfaces. The solid substrate was obtained from β-cristobalite; all nonbridging oxygen atoms were protonated. The resultant surface density of OH groups was ∼4.54 sites per nm2. The simulations were conducted at constant temperature, 300 K, and at increasing bulk methane pressure for pores of width 1.0 nm. For bulk systems, these thermodynamic conditions are outside the window of methane hydrates stability. Methane solubility in confined water was found to far exceed that in bulk systems. The increase in tangential pressure, observed under confinement, cannot solely explain the marked increase in solubility predicted by our simulations. Most likely, the structure of confined water favors the sequestration of methane. The excess chemical potential for methane was found to significantly decrease within the confined water compared with that in the bulk phase. On the basi.
A comparative pressure tuning hole burning study of protoporphyrin IX in myoglobin and in a glassy host

We measured the behavior of spectral holes under isotropic pressure changes as a function of burn frequency. We compared a protein sample, namely protoporphyrin IX substituted myoglobin in a glycerol/water glass with a sample where the protoporphyrin IX was directly dissolved in a host glass. The differences are remarkable—holes in the pure glass behave as expected for a homogeneous isotropic material. It is the nonlinear frequency dependence of the pressure shift where the deviation of the protein sample is most obvious. These observations signal a correlation between the structures of the dye probe and the structures of the apoprotein. They further show that global parameters of the apoprotein, such as the isothermal compressibility, depend strongly on the associated conformational substates and are subject to unexpected large variations.
The influence of visual environment and sympatry on plumage coloration in New World warblers

Several factors may drive interspecific divergence, and investigating possible mechanisms from multiple angles may be most efficient for understanding the evolutionary history of diverse groups. The main objective of my thesis was to examine mechanisms that may promote plumage divergence in Parulidae warblers. In my first study, I investigated the signalling environments of 17 sympatric species of warblers to test predictions of sensory drive. I determined sexual selection has likely influenced plumage evolution in warblers, plumage and visual environment coloration were correlated, and warblers were not most conspicuous in chosen display environments. In my second study, I tested the relationship between sympatry and plumage divergence across 77 species and found an increase in sympatry is correlated with greater plumage divergence, and that closely related species tended to be highly sympatric. My thesis demonstrates multiple selective pressures have likely shaped the evolution of plumage coloration in this diverse group of birds.
Computational Analysis of an Instantaneous Chemical Reaction in a T-Microreactor

We extend and apply a method for the numerical computation of convective and diffusive mixing in liquid systems with very fast irreversible chemical reaction to the case of unequal diffusivities. This approach circumvents the solution of stiff differential equations and, hence, facilitates the direct numerical simulation of reactive flows with quasi-instantaneous reactions. The method is validated by means of a neutralization reaction which is studied in a T-shaped micromixer and compared with existing experimental LIF-data. Because of their large are-to-volume ratio, microreactors are well suited for fast chemical reactions which are seriously affected by the slow diffusive transport in aqueous media. Numerical computations for different reactor dimensions reveal the fact that, in a dimensionless setting, the obtained conversion is independent of the reactor size, if the flow conditions are the same. This corresponds to an increase of space-time-yield proportional to the square of the inverse scale factor.
Compositions of the Volatiles of Peel Oil and Juice from Citrus Unshiu

Volatile components of peel oil and juice from Citrus unshiu were studied. The peel oil and aroma concentrate from the juice were separated into hydrocarbons and oxygenated compounds by column chromatography. These fractions were analyzed by gas chromatography and combined gas chromatography and mass spectrometry.Ninety-eight percent of the peel oil consisted of hydrocarbons such as d-limonene, γ-terpinene, myrcene and α-pinene. The aroma concentrate from the juice was composed of the same hydrocarbons (60%) and oxygenated compounds (40%) such as 3-methylbutanol, cis-3-hexenol, trans-2-hexanal and n-hexanal. Ninety percent of the oxygenated compounds was alcohols and aldehydes.
Compressibility to 7 GPa at 298 K of the protonated octahedral framework mineral burtite, CaSn(OH)6

Abstract The equation of state of synthetic deuterated burtite, CaSn(OD)6, has been determined to 7.25 GPa at 298 K by synchrotron X-ray powder diffraction. Fitting to a third-order Birch-Murnaghan equation of state gives K0 = 44.7(9) GPa and K0ʹ = 5.3(4). A second-order fit gives K0 = 47.4(4) GPa. Within experimental error the two fits are indistinguishable over the pressure range studied. The decrease in the a parameter with pressure is smooth and no phase transitions were observed. Burtite is much more compressible (by a factor of three or four) than CaSnO3 and CdSnO3 perovskites, indicating that the absence of a cavity cation has a major effect upon the compressibility of the octahedral framework. Burtite is also markedly more compressible than the closely-related mineral stottite FeGe(OH)6 (K0 = 78 GPa). Their different compressibilities correlate with the relative compressibilities of stannate and germanate perovskites. Although different octahedral compressions are likely to be the primary reason for the different compressibilities of burtite and stottite, we also consider the possible secondary role of hydrogen-bonding topology in affecting the compressibilities of protonated octahedral frameworks. Burtite and stottite have different hydrogen-bonding topologies due to their different octahedral-tilt system. Burtite, space group Pn3̅ and tilt system a+a+a+, has a hydrogen-bonded network of linked four-membered rings of O-H.O linkages, whereas stottite, space group P42/n and tilt system a+a+c-, has <100> O-H.O crankshafts and isolated four-membered rings. These different hydrogen-bonded configurations lead to different bracing of the empty cavity sites by the O-H.O linkages and very different hydrogen-bonding connectivities in these two minerals that may also enhance the difference between their compressibilities.
N.M.R. studies of water proton relaxation in Sephadex bead suspensions

The effects of morphology and diffusive exchange on N.M. R. water proton transverse relaxation times in a model heterogeneous system consisting of packed Sephadex beads are interpreted within a unified theoretical framework based on the Bloch-Torrey equations. The relaxation depends on the radii of the Sephadex beads, the cross-linking density of the dextran and varies with the C.P.M.G. interpulse spacing. The larger beads show multiexponential relaxation with up to three components. Without recourse to concepts such as ‘bound-water’ or ‘multiple site occupancy’ we show how the data can be simply understood as arising from diffusive exchange between regions having different relaxation times and resonance frequencies.
Voltage against current curves of cation exchange membranes

The voltage against current curves of cation exchange membranes have been studied. They have a characteristic shape with a region of slow current variation (the plateau) followed by a region of accelerated current growth as the voltage is increased (the inflexion). For currents much greater than the “limiting” one determined by the value at the “plateau” of the (V, C) curve, the current is transferred across the membrane mainly by the cations of the salt; the contribution of “water splitting” is minor.Experiments on suppressing convection near the membrane with the aid of microporous filters have shown that such convection cannot be responsible for the inflexion of the voltage against current curves, and for the passage through the membrane of current much greater than the “limiting” value.It was shown on the basis of a simple theoretical model that formation near the membrane of a region of the volume charge, reflected in replacing the electroneutrality condition by the full Poisson equation, may lead to passage through the membrane of currents greater than the “limiting” one; the voltage against current curves of the general form described above with an inflexion, were then obtained using computation. The asymptotic behaviour of these voltage against current curves at large voltages was studied.
The feasibility of adopting zeolite in phosphorus removal from aqueous solutions

AbstractExcess phosphorus in waterways can cause serious eutrophication, a phenomenon which could eventually result in water quality crisis. Thus, there is a need to seek appropriate ways to remove phosphorus from wastewater. This investigation evaluates the potential of two types of sorbents, granular zeolite (A) and globular zeolite (B), for phosphorus removal. The comparative adsorption of phosphorus from aqueous solutions by A and B is tested using batch experiments. For A and B, the assessed optimum pH is 1.8 and 2.0, sorbent dosage 2.5 and 30 g (per 100 ml aqueous solution, and the contact time intervals 20 and 40 min, respectively. The initial phosphorus concentration for both sorbents was 20 mg/L. The analysis of the results demonstrates that sorbent A has better adsorption characteristics than B. To describe the equilibrium adsorption isotherms, Langmuir and Freundlich models are applied to the data. The Langmuir isotherm adequately describes adsorption for both of these sorbents, with an R2 good.
Structure of the T6 Human Nickel Insulin Derivative at 1.35 A Resolution.

Abstract. This paper presents results of the structural investigation on the human insulin hexamer deri-vative stabilised by nickel coordination. Single crystals of the Ni-insulin derivative were prepared by the hanging drop vapour diffusion crystallisation method using metal-free insulin and nickel(II) acetate tetra-hydrate. The low-temperature crystal structure was determined by the single crystal X-ray crystallographic method with data extending to 1.35 A spacing. The investigated insulin derivative exhibits the T 6 form of insulin and crystallizes in the trigonal system in space group R 3, with the unit cell parameters a = b = 81.41 A and c = 33.75 A. There are two nickel atoms per insulin hexamer and both are octahedrally coor-dinated by three N e2 atoms of three symmetry-related HisB10/HisD10 and three oxygen atoms of three symmetry-related water molecules. Keywords: insulin derivative, nickel, X-ray structure INTRODUCTION Insulin is a hormone synthesized in humans and other mammals within the β-cells of the islets of Langerhans in the pancreas. It regulates carbohydrate metabolism and is also involved in the metabolism of fat and pro-teins. Insulin is used to control the level of blood sugar in patients with Type 1 diabetes mellitus and occasion-ally in some patients with Type 2 diabetes mellitus. The molecule is structured of two polypeptide chains, chain A consisting of 21 and chain B of 30 amino acids. Chain A and chain B are linked by two disulphide bridges, while the third disulphide bridge links residues A6 and A11 by an intra-molecular bond. In the presence of zinc ions and some other divalent cations, insulin forms hexamers. Although insulin is accumulated in the pancreas as a Zn
Evaluation of a Line Heat Dissipation Sensor for Measuring Soil Matric Potential

The accuracy and operational limits of a new heat dissipation sensor for measuring soil matric potential are evaluated. The measurement is based on the rate of temperature rise from a line heat source embedded in a cylindrical porous ceramic that is in equilibrium with soil water. Different heating currents or times can be accounted for by basing calibration on sensor thermal conductivity rather than temperature rise. Six sensors were calibrated against pressure plate and psychrometer measurements of matric potential. Inverse of sensor thermal conductivity was linearly related to the logarithm of matric potential between - 10 and - 1200 J kg -1 . This range of measurable matric potentials is much larger than previous heat dissipation sensor designs. The heat dissipation sensor was accurate to within 20% of the independently measured matric potential. Normalizing sensor readings by sensor thermal conductivity after oven drying results in a calibration that accounts for between-sensor variability. In a growth chamber experiment with fluctuating soil temperatures, heat dissipation sensor estimates of soil matric potential compared favorably with tensiometer and psychrometer measurements. Heat dissipation sensors based on this design appear useful when a wide range of matric potentials needs to be studied.
Review of Catalytic Hydrogen Generation in the Defense Waste Processing Facility (DWPF) Chemical Processing Cell

This report was prepared to fulfill the Phase I deliverable for HLW/DWPF/TTR-98-0018, Rev. 2, ''Hydrogen Generation in the DWPF Chemical Processing Cell'', 6/4/2001. The primary objective for the preliminary phase of the hydrogen generation study was to complete a review of past data on hydrogen generation and to prepare a summary of the findings. The understanding was that the focus should be on catalytic hydrogen generation, not on hydrogen generation by radiolysis. The secondary objective was to develop scope for follow-up experimental and analytical work. The majority of this report provides a summary of past hydrogen generation work with radioactive and simulated Savannah River Site (SRS) waste sludges. The report also includes some work done with Hanford waste sludges and simulants. The review extends to idealized systems containing no sludge, such as solutions of sodium formate and formic acid doped with a noble metal catalyst. This includes general information from the literature, as well as the focused study done by the University of Georgia for the SRS. The various studies had a number of points of universal agreement. For example, noble metals, such as Pd, Rh, and Ru, catalyze hydrogen generation from formic acid and formate ions, and more acid leads to more hydrogen generation. There were also some points of disagreement between different sources on a few topics such as the impact of mercury on the noble metal catalysts and the identity of the most active catalyst species. Finally, there were some issues of potential interest to SRS that apparently have not been systematically studied, e.g. the role of nitrite ion in catalyst activation and reactivity. The review includes studies covering the period from about 1924-2002, or from before the discovery of hydrogen generation during simulant sludge processing in 1988 through the Shielded Cells qualification testing for Sludge Batch 2. The review of prior studies is followed by a discussion of proposed experimental work, additional data analysis, and future modeling programs. These proposals have led to recent investigations into the mercury issue and the effect of co-precipitating noble metals which will be documented in two separate reports. SRS hydrogen generation work since 2002 will also be collected and summarized in a future report on the effect of noble metal-sludge matrix interactions on hydrogen generation. Other potential factors for experimental investigation include sludge composition variations related to both the washing process and to the insoluble species with particular attention given to the role of silver and to improving the understanding of the interaction of nitrite ion with the noble metals.
Wound Effects in the Xylem of Acer and Betula Species

The tissues present at wounding and those that developed after wounding in Acer rubrum L. and Betula papyrifera Marsh, were examined anatomically and histochemically, and with permeability studies. 1. The changes in the xylem formed by the cambium after wounding were similar in pattern for Acer and Betula. The amount of parenchyma increased. Vessels decreased in amount and diameter. They formed more connecting vessels. The amount of fibers remained about constant. In Betula there was a reduction in fiber length and thickness of the walls. The barrier zone in Acer had a higher amount of rays and was obviously more effective. 2. The greater longitudinal extent of discoloration in Betula over Acer in the tissues present at wounding was because of accessory compounds that developed in the Strand and ray parenchyma of Acer species and diffused afterwards through large pits into the lumen of the vessels, thus plugging them. The vessels of Betula with small pits remained empty. Only the scalariform plates showed a thin layer of encrustations. Gasses and microorganisms could penetrate longitudinally more easily. 3. The Variation in the longitudinal extent of discoloration between individual trees of Acer rubrum appeared to be correlated with the different amount of vessel plugs and not with vessel size. But, in Betula papyrifera^ where almost no encrustations developed in the lumen of the vessels, the average size of the individual vessel may explain to a great extent, the within species variations.
Germicidal Properties of Ozonated Sunflower Oil

The aim of this work was to establish the minimal inhibition concentration (MIC) of ozonated sunflower oil for various microorganisms. To determine the influence of the ozonated medium on the growth of bacteria Bacillus subtilis, Escherichia coli and yeast Candida albicans the Petri dish method was used. Chemical and physical properties of ozonated sunflower oil were additionally studied. Microbiological studies proved that these microbes have various sensibility against ozonated oil. The most resistant are gram-negative bacteria E. coli and the yeast C. albicans. Gram-positive bacteria, B. subtilis turned out to be less resistant, because no growth was observed for preparation with an ozone dose of 200 mgO3/g oil.
The metamictization of zircon: Radiation dose-dependent structural characteristics

A suite of gem zircon samples from Sri Lanka has been studied using infrared (IR) spectroscopy, X-ray diffraction, and chemical analysis. The degree of metamictization of the zircon, as indicated by unit-cell parameters, increases systematically with U-Th content up to the point of total metamictization. The appearance of IR spectra also varies as a function of metamictization; band widths increase and intensities decrease with increasing U-Th contents. Persistence of bands related to Si-O bonds and disappearance of bands related to Zr-O bonds indicates that the structure of metamict zircon consists of distorted and disoriented isolated silica tetrahedra with few if any undisplaced Zr cations. All spectroscopic indicators of crystalline order show that total metamictization is reached at an accumulated radiation dosage of ~4.5 x 10^(15) alpha decay events per mg. Hydrous components enter the structure only after total metamictization, but the amounts are not correlated with U-Th content. In all cases OH was the only hydrous species detected.
Dissolution of precious metals in supercritical carbon dioxide

Precious metals including copper, gold, and palladium can be dissolved in supercritical CO2 by oxidation with HNO3 and subsequent chelation with hexafluoroacetylacetone to form CO2-soluble metal β-diketonate complexes. The oxidizing agent HNO3 is carried into the supercritical fluid phase by the CO2-soluble Lewis base tri-n-butyl phosphate (TBP) as a complex of the general form TBP(HNO3)x(H2O)y. For the dissolution of Pd metal, a Lewis acid−base complex of the form TBP(HNO3)1.0(H2O)0.4 is required. Au and Cu can be oxidized with a lesser amount of HNO3 in the complex. This supercritical fluid dissolution technique provides a “dry” method for recovering precious metals from abandoned electronics and spent catalysts with minimum waste generation.