Miracle-dz/UniFAR-FTUs huggingface dataset:
Gas-to-solid condensation in a Mg–SiO–H2–O2 vapor: metastable eutectics in the MgO–SiO2 phase diagram

Kinetically controlled gas-to-solid condensation in Mg–SiO–H2–O2 vapors resulted in the formation of amorphous, chemically ordered, solid compositions at 26 ± 7, 46.5 ± 2 and 87 ± 3.5 wt. % MgO. The first two solid compositions match those of metastable eutectics in existing MgO–SiO2 phase diagrams. An explanation for the highest-MgO metastable solid compositions requires a revision of this phase diagram to include a eutectic at ∼95 wt. % MgO.
Metal supported carbon nanostructures for hydrogen storage

Carbon nanocones are the fifth equilibrium structure of carbon, first synthesized in 1997. They have been selected for investigating hydrogen storage capacity, because initial temperature programmed desorption experiments found a significant amount of hydrogen was evolved at ambient temperatures. The aim of this thesis was to study the effect of impregnation conditions on metal catalyst dispersion and to investigate whether the metal loaded cones had improved hydrogen storage characteristics. Pre-treatment of carbon nanocones with hydrogen peroxide was carried out, followed by metal decoration in aqueous solution by an incipient wetness technique. Two methods of reducing the metal catalyst have been applied: in hydrogen at room temperature (RT) and in an aqueous solution of NaBH4. X ray diffraction (XRD) technique confirmed the complete metal reduction and transmission electron microscope (TEM) analysis showed that the reduction technique affected the catalyst dispersion. Very fine dispersions of ca. 1 nm diameter metal clusters at catalyst loadings of 5 wt% were achieved and high dispersions were retained for loadings as high as 15 wt%. Hydrogen uptakes at RT were measured and an increase with metal loading was observed. In comparison the same route of pre-treatment and metal impregnation has been done over graphite nanofibres (GNF) and the hydrogen uptake showed an adsorption superior of the cumulative contribution of the substrate and metal catalyst attributing this to hydrogen spillover. The GNF have been impregnated also with another metal catalyst Ni showing as well the phenomenon of hydrogen spillover. The attempt to impregnate the carbon nanocones with a mixture of Pd-Ni, Pd-Cu and Pd-Ag resulted in an increase of hydrogen uptake for the first two but a decrease for the last of these. The carbon nanocones have been also impregnated with a Mg organometallic precursor dibutyl magnesium (DBM) and then decomposed without the use of hydrogen environment synthesizing successfully MgH2. The stoichiometry and the enthalpy of this decomposition have been studied. Furthermore, the DBM has been mixed with another hydride LiALH4 and the decomposition reaction of the complex hydride has been studied.
Compression Dewatering of Particulate Suspensions and Sludge: Effect of Shear

Experiments were carried out at the lab-scale to study the effect of a shearing action in a compression dewatering process. The impact of different process parameters, such as shear rate, filter-cake thickness, and pressure, on the final dry solid fraction was analyzed. Also, materials with different degrees of compressibility have been used. For slightly and moderately compressible materials (talc and kaolin, respectively), significantly higher final dry solid fractions (up to 0.79 wt/wt with talc and 0.75 wt/wt with kaolin) were obtained in the presence of a torsion shear. This behavior may mainly be explained by a rearrangement of the solid particles within the cake induced by the radial forces. A low shear rate (around 0.7 s−1) was generally sufficient to cause a quite significant increase in the cake dryness (a 12.8% increase was observed with 11-mm-thick talc cakes). A further increase in the shear did not lead to noticeable changes in the final dry solid fraction in the cakes. Otherwise, reducing the filter-cake thickness was beneficial for the dewatering. For talc cakes, the dry solid fraction was increased by 21% for a 3 mm thickness against 7% for a 25 mm thickness. With a highly compressible material, such as activated sludge, the filter-cake dryness did not change with the application of a shearing action. This behavior may be mainly attributed to the fact that biological sludge dewatering is markedly influenced by a low permeability skin at the cake/medium interface, which is very thin and not perturbed by shear forces, due to the cake thickness. The low rigidity of the solid matter in this particular case may also limit the reorientation of the particles.
Self-Diffusion of Supercooled Water to 238 K Using PGSE NMR Diffusion Measurements

The translational self-diffusion coefficients of supercooled water at atmospheric pressure were examined using pulsed-gradient spin−echo NMR diffusion measurements down to 238 K. As the temperature decreased, the diffusion behavior became distinctly non-Arrhenius. It was found that the diffusion behavior when plotted in an Arrhenius form was well-described by a Vogel−Tamman−Fulcher-type relationship in the temperature range from 298 to about 242 K. However, a fractional power-law-type equation was found to provide a better fit that extended over the entire measured temperature range. Below this temperature range, the diffusion coefficient decreased rather steeply, and at 238 K, the diffusion coefficient was 1.58 × 10-10 m2 s-1, the lowest value of the water diffusion coefficient so far determined. At this temperature the activation energy for the diffusion was found to be of the order of 44.4 kJ mol-1. The data presented here should allow theoretical models of water to be more stringently tested.
Pengaruh Takaran Pupuk Nitrogen dan Silika terhadap Pertumbuhan Awal (Saccharum officinarum L.) pada Inceptisol

INTISARI Percobaan ini dilaksanakan pada bulan April sampai Agustus 2013 pada inceptisol di Kebun Percobaan Tridarma, Fakultas Pertanian, Universitas Gadjah Mada, Yogyakarta. Tujuan penelitian adalah untuk mengetahui pengaruh takaran pupuk silika dan takaran pupuk nitrogen terhadap pertumbuhan tebu. Rancangan percobaan yang digunakan dalam penelitian ini adalah Rancangan Acak Lengkap dengan 3 ulangan. Faktor pertama adalah takaran urea yaitu sebagai sumber unsur nitrogen terdiri dari 0 kg/ha, 150 kg/ha, 300 kg/ha, dan 450 kg/ha. Faktor kedua adalah takaran Si-PlusHS sebagai sumber unsur silika terdiri dari 0 kg/ha, 250 kg/ha, dan 500 kg/ha. Varietas yang digunakan dalam percobaan ini adalah Bululawang yang ditanam pada media inceptisol menggunakan polibag. Variabel yang diamati dalam penelitian ini adalah tinggi tanaman, jumlah daun, luas daun, kehijauan daun, diameter batang, jumlah ruas, jumlah anakan, volume akar, panjang akar, berat segar tajuk, berat segar akar, berat segar total, berat kering tajuk, berat kering akar, berat kering total. Hasil penelitian menunjukkan terdapat interaksi antara nitrogen dengan silika yang diaplikasikan dan pada takaran 150 kg/ha urea dengan 250 kg/ha Si-PlusHS menunjukkan hasil yang baik pada variabel pertumbuhan tanaman yaitu tinggi tanaman, jumlah daun, luas daun, diameter batang, jumlah ruas, panjang akar, volume akar, berat segar tajuk, berat segar akar, berat segar total, berat kering tajuk, berat kering akar, berat kering total. Kata kunci : silika, tebu, urea
Investigation of transient phenomena of proton exchange membrane fuel cells

The research presented in this thesis is a contribution to the modeling and understanding of the dynamic behavior of proton exchange membrane fuel cells (PEMFCs). A time-dependent, two-phase non-isothermal model of the membrane electrode assembly was developed and implemented using the finite element method. In addition to solving a phenomenological transport equation for water in the membrane, the model takes into consideration the non-equilibrium water sorption to better capture some of the dynamic characteristics of water transport in the MEA. Mass transfer using Fickian diffusion is implemented in the model. Two different models describing the electrochemical reactions in the catalyst layer including a macro-homogeneous model and an agglomerate model, are also implemented. Conservation of energy is included in the solution procedure in order to assess the impact of thermal effects on the
Impact of cathode evaporation on a free-burning arc

Summary form only given, as follows. In the center of a free-burning, high-intensity argon arc at atmospheric pressure, a highly ionized vapor beam of copper has been generated by a continuous feeding of a thin (0.5- and 1-mm-diameter) copper wire to the hot surface region of the cathode in the vicinity of the plasma attachment. The copper vapor is carried into the plasma column between the electrodes by the self-magnetic field induced plasma flow caused by the conical shape of the cathode. In order to study the vapor beam, the arc was modeled at atmospheric pressure, with a current of 150 A, a gap spacing of 1 cm, a cathode tip of 60°, and a copper vapor flow of 1 mg/s. The temperature, mass flow, current flow, and Cu concentration were calculated for the entire plasma region. The intensity. distribution of the CuI spectral line at 5218.2 Å was also recorded by emission spectroscopy and compared with the calculated values. The copper vapor in the cathode region has velocities of 210 m/s with a mass concentration of above 90% within 0.5 mm from the arc axis. The vapor passes from the cathode toward the anode with a slight diffusion in the argon plasma. Higher temperatures and current densities in the core of the arc, caused by the cathode evaporation, were found
Computational studies of cation and anion ordering in cubic yttria stabilized zirconia

The investigation of ordering and phase stability in the ZrO2-Y2O3 system involves two sets of calculations. The first set of calculations uses the cluster expansion method. A guide to the practical implementation of the cluster expansion outlines methods for defining a goal and choosing structures and clusters that best model the system of interest. The cluster expansion of the yttria stabilized zirconia system considers 447 configurations across the ZrO2-Y2O3 composition range. The effective cluster interaction for pair clusters show electrostatic repulsion between anions and little interaction between cations. Triplet anion terms largely modify the energy contributions of the pair terms. Separate cluster expansions using structures at single compositions show that cation clusters become more important at high yttria composition. The cluster expansion led to the discovery of three previously unidentified ordered ground state structures at 25, 29, and 33 % Y on the cubic fluorite lattice. The ground state with 33 % Y is stable with respect to the calculated energies of monoclinic ZrO2 and the Y4Zr3O12 ground state. The ground states have the common ordering feature of yttrium and vacancies in [1 1 2] chains, and Monte Carlo simulations show that vacancy ordering upon cooling is contingent on cation ordering. The second set of calculations consider three driving forces for order: ionic relaxation, vacancy arrangements, and differences in Zr and cation dopant radii. Bond valence sums of fully relaxed and anion relaxed structures are nearly equal at all compositions. In supercells of ZrO2, the vacancy arrangement of the ground state with 25 % Y is more stable than arrangements maximizing the distance between vacancies or aligning vacancies in [1 1 1]. Comparing the YSZ ground state with structures of the same configuration with scandium replacing yttrium shows different stable phases on the convex hull between cubic ZrO2 and the dopant M2O3 phase. The change in the stability of the configurations may be a result of cation radius sizes. The factors suggest that the driving forces of phase stability depend on composition. 3 Thesis Supervisor: Gerbrand Ceder Title: R.P. Simmons Professor of Materials Science and Engineering
InAs/AlSb heterostructure field-effect transistors using a Si-doped InAs/AlSb short-period superlattice modulation doping barrier

Modulation doping of InAs/AlSb quantum wells generally requires the use of chalcogenide donor impurities because silicon, the usual donor of choice in molecular beam epitaxy, displays an amphoteric behavior in antimonide compounds. In the present article, we demonstrate the use of a Si-doped InAs/AlSb short-period superlattice (with Si co-deposited with the InAs) to modulation dope the current-carrying InAs channel of an InAs/AlSb heterostructure field-effect transistor (HFET). Using this new approach, we have fabricated 1.5 μm gate InAs/AlSb HFETs with a measured extrinsic transconductance of 550 mS/mm at 300 K. The present band gap engineering approach eliminates the requirement for captive chalcogenide donor sources to modulation dope InAs/AlSb quantum wells. Design alternatives to the use of the short-period superlattice are also considered and demonstrated.
Synthesis and Characterisation of Hydrated Calcium Pyrophosphate Phases of Biological Interest

The details of a synthesis method for biologically relevant hydrated calcium pyrophosphates (CPPs, Ca2P2O7·nH2O) has been elucidated. Control of the pH (from 3.6 to 5.8) and the temperature (from 25 to 90 °C) during the synthesis enabled the preparation of four pure CPP phases within one hour without intermediates: monoclinic and triclinic calcium pyrophosphate dihydrate (CPPD, Ca2P2O7·2H2O), which are the two CPP phases detected in vivo in joints of arthritic patients, monoclinic tetrahydrate β (CPPT, Ca2P2O7·4H2O) and an amorphous phase (a-CPP, Ca2P2O7·nH2O). Four domains corresponding to the four different phases of hydrated calcium pyrophosphate were identified; a-CPP was synthesised over a very wide pH and temperature range (up to 90 °C) within the domain of synthesis conditions explored, including physiological conditions (pH 7.4 and 37 °C). The as-synthesised hydrated CPP phases were characterised by complementary techniques (powder X-ray diffraction, FTIR and Raman spectroscopy, scanning electron microscopy and thermogravimetry) and chemical analyses. Rietveld refinement analyses of the as-synthesised crystalline phases were performed, andthere were significant differences between the m-CPPD Xray diffraction pattern observed and previously published cell parameters. Vibrational spectroscopy allowed the crystalline and amorphous phases synthesised to be clearly distinguished and identified owing to the high flexibility of the pyrophosphate anion. Chemical analyses showed that the synthesis conditions used in this study did not allow significant hydrolysis of the pyrophosphate ions into phosphate ions, and the number of water molecules associated with each synthesised CPP phase was determined by thermogravimetric analysis. Different mechanisms of dehydration were also identified. The study of the formation of synthetic and well-characterised hydrated calcium pyrophosphate phases and their availability in large amounts in vitro could allow progress to be made on the biological role of these phases and their possible transformations. This could also aid their detection in patients suffering from disease caused by calcium salt crystals and could clarify the mechanism by which CPP crystals form and evolve in vivo.
Diffusion of Sorbing Organic Chemicals in the Liquid and Gaseous Phases of Repacked Soil

Transport models for sorbing organic chemicals in soil require accurate predictions of the diffusion and sorption processes in both the liquid and gaseous phases. In this study, the ability of recently-presented diffusivity models in combination with equilibrium sorption models to predict the effective (i.e., including sorption effects) diffusion coefficient, D eff , as a function of soil-water content, θ, is tested for different sorbing organic chemicals in different soils. The water-induced linear reduction (WLR) gas diffusivity model, combined with a two-component (hydrophobic and vapor) equilibrium sorption model, well described short-term ( 700 h. Consequently, an increasing K D value with time was required in the DATES model to obtain successful D eff (θ) predictions. Since chemical-soil contact time and adsorption-desorption history typically vary in each compartment of a soil profile, transport models, including sorption kinetics, will become very complex and DATES with a time-dependent K D relation may represent a useful model alternative.
Integrated Management of Tomato Sclerotinia Rot Disease by using the Combined Treatments between Compost , Bioagents and some Commercial Biocides

Efficacy of compost, bioagents and some commercial biocides individually or in combination for controlling tomato sclerotinia rot caused by Sclerotinia sclerotiorum (Lib.) de Bary under greenhouse and field conditions were studied. Results indicated that Trichoderma album and Bacillus subtilis were the most effective bioagents in inhibiting mycelial growth of S. sclerotiorum in vitro. All treatments significantly reduced disease incidence and severity of tomato white rot disease compared with untreated control. However, T. album and Pseudomonas fluorescens combined with compost reduced the disease incidence and disease severity from 100 and 77.40 in control to 11.1 & 1.5% and 11.1 & 2.5%, respectively, under greenhouse conditions. The integrated T. album, P. fluorescens and Bio-Zeid with compost recorded the highest increase of fresh weight and dry weight of shoots and roots compared with individual treatments and control. Under field conditions, adding compost to the soil pre-transplanting decreased the percentage of infection and increased yield of tomato plants compared with other treatments with compost. In this respect, the integration between T. album + B. subtilis + Ps. fluorescens and compost was the most effective treatment for reduced the disease incidence and disease severity. As well as, this treatment increased the fruit weight per plant. On the side, all treatments increased the phenols and flavonoids content in tomato plants. The highest increase in the total phenols and flavonoids contents were recorded with T. album, P. fluorescens and Bio-Zeid combined with compost. Also, all treatments increased peroxidase (PO), polyphenoloxidase (PPO), chitinase and β-1, 3glucanase activities in treated tomato plants. It could be concluded, the combination between compost, bioagents and some commercial biocides might be useful as an useful tool for controlling tomato sclerotinia disease under greenhouses and field conditions.
Low and high NOx tropospheric photochemistry

Emission inputs to the troposphere are processed in two fundamentally different ways, leading to two atmospheric states with greatly different properties. We define these states in terms of rates of NOx emissions and radical production. In the low NOx state, trace gas inputs to the atmosphere are removed primarily by oxidation reactions. In the high NOx state the oxidative potential of the atmosphere is greatly diminished and primary pollutants build up, as alternate removal processes are slow. We show here that this dual behavior is due to a titrationlike reaction between NOx and free radicals in which either reactant can be in excess.
Cu2S-incorporated ZnS nanocomposites for photocatalytic hydrogen evolution

Sodium Lauryl Sulphate (SLS) surfactant and propylene diamine (PD), assisted wet chemical synthesis was used to make ZnS–Cu2S nanoflakes wherein the added copper(II) transforms into copper(I) sulphide and is found to be deposited on the surface of ZnS. With a variation of copper concentration from 0 to 5% there is a morphological transformation from ZnS nanorods eventually to ZnS–Cu2S nanoflakes through a transition morphology of nanocactus leaves. During the addition of copper there is an incorporation of Cu2S into the ZnS phase (100) as is clearly evidenced by various characterization methods. Visible light photocatalytic hydrogen production activities using these nanoflakes of ZnS–Cu2S are reported with good results. The influence of Cu2S shifts the band gap of ZnS from the UV to the visible region, reducing the need for an expensive co-catalyst like platinum for photolysis of water. Though hydrogen production is not as high as that depicted by other earlier works the material that we have created is a relatively cheap, simple two component heterostructure with no expensive third component. It is also free from toxic materials such as CdS. However, our results are better than for most other copper loaded ZnS systems in the literature. Furthermore, the morphological evolution to nanoflakes from nanorods, the concentration and dispersion of Cu2S over ZnS and the interface between Cu2S and ZnS semiconductors play a vital role in hydrogen production. 5% Cu2S on ZnS seems to be the optimum concentration for maximum evolution of hydrogen.
Synthesis of alumina supported Pd–Cu alloy nanoparticles for CO oxidation via a fast and facile method

Supported Pd–Cu alloy nanoparticles have been successfully synthesized via a fast, facile and environmentally friendly method by simultaneous reduction of Pd(NO3)2 and Cu(NO3)2. The catalyst contains Pd–Cu nanoparticles with higher alloying degree, smaller particle size, higher ratio of Pd0, Cu+, and chemisorbed oxygen species, and therefore exhibits enhanced CO oxidation activity.
CFD Simulation of Particle Distribution in Stirred Vessels

In this work the particle concentration distribution in two-phase stirred tanks is simulated on the basis of information on the three-dimensional flow field, as obtained by numerical solution of the flow equations (CFD) using the well known k –ɛ « turbulence model. Two modelling approaches are attempted. In the simpler method the flow field is first simulated neglecting the influence of the solid phase; on the basis of the resulting flow field a very simple sedimentation model is employed for solving the solids mass balance equations in order to compute the particle concentration field. In this case no inertial effects on the solid particles are considered, so that the convective and diffusional exchanges for the solid phase are assumed to coincide with those for the liquid phase. In the more advanced approach the momentum balance equations for both the solid and liquid phases are simultaneously solved. Experimental data on the axial profiles of particle concentration have been obtained in a laboratory scale agitated tank. The experimental technique utilized is non intrusive being based on light attenuation measurements and is also able to provide information at high particle concentrations. The comparison of experimental data with simulation results is satisfactory with both simulation approaches. Differences between the two approaches concerning their accuracy and computational effort are discussed. The need to make a suitable estimate of the particle drag coefficients in turbulent fluid media is emphasized.