Miracle-dz/UniFAR-FTUs huggingface dataset:
Vegetation Effects on Soil Organic Carbon Quality in an Arid Hyperthermic Ecosystem

Abstract Arid lands occupy substantial global land area and thus may play an important role in the terrestrial carbon cycle. This study examined a facet of arid land carbon cycling by examining variation in plant and soil organic carbon quality and the physical partitioning of carbon into aggregate and mineral-associated fractions for soils dominated by Prosopis velutina (mesquite), Larrea tridentata (creosote), and a combination of Bouteloua barbata, Bouteloua aristidoides, Aristida adscensionis, and Cynodon dactylon (mixed grass) vegetation types in an arid hyperthermic ecosystem. We used a combination of density fractionation to quantify physical distribution of organic carbon, in addition to isotopic, thermal, and spectroscopic techniques to quantify carbon quality in each fraction. Data indicated that most of the soil carbon across all vegetation types was concentrated in free light fractions, with little role for aggregate occlusion or mineral adsorption. Differential thermal analysis and derivative thermogravimetry indicated that all vegetation types were dominated by thermally labile material (exothermic peak and mass loss at ∼350°C), with the greatest differences in carbon quality noted among the respective plant materials. Diffuse reflectance Fourier transform infrared spectroscopy also indicated that the most substantial variation in organic carbon chemical quality was among the various plant materials. In particular, the creosote plant material exhibited a distinct high-temperature exothermic peak near 515°C, the greatest specific enthalpy (20 kJ g−1 biomass), and a relatively greater proportion of aromatic components as determined by diffuse reflectance Fourier transform infrared spectroscopy. Furthermore, the data indicated substantial alteration of chemical and thermal properties as organic material progressed from plant material to the soil fractions with a convergence on organic material dominated by polysaccharides and substantial reduction in specific enthalpy in the soil fractions.
The Synergism Between Heat and Mass Transfer Additive and Advanced Surfaces in Aqueous LiBr Horizontal Tube Absorbers

Experiments were conducted in a laboratory to investigate the absorption of water vapor into a falling-film of aqueous lithium bromide (LiBr). A mini-absorber test stand was used to test smooth tubes and a variety of advanced tube surfaces placed horizontally in a single-row bundle. The bundle had six copper tubes; each tube had an outside diameter of 15.9-mm and a length of 0.32-m. A unique feature of the stand is its ability to operate continuously and support testing of LiBr brine at mass fractions {ge} 0.62. The test stand can also support testing to study the effect of the failing film mass flow rate, the coolant mass flow rate, the coolant temperature, the absorber pressure and the tube spacing. Manufacturers of absorption chillers add small quantities of a heat and mass transfer additive to improve the performance of the absorbers. The additive causes surface stirring which enhances the transport of absorbate into the bulk of the film. Absorption may also be enhanced with advanced tube surfaces that mechanically induce secondary flows in the falling film without increasing the thickness of the film. Several tube geometry's were identified and tested with the intent of mixing the film and renewing the interfacemore » with fresh solution from the tube wall. Testing was completed on a smooth tube and several different externally enhanced tube surfaces. Experiments were conducted over the operating conditions of 6.5 mm Hg absorber pressure, coolant temperatures ranging from 20 to 35 C and LiBr mass fractions ranging from 0.60 through 0.62. Initially the effect of tube spacing was investigated for the smooth tube surface, tested with no heat and mass transfer additive. Test results showed the absorber load and the mass absorbed increased as the tube spacing increased because of the improved wetting of the tube bundle. However, tube spacing was not a critical factor if heat and mass transfer additive was active in the mini-absorber. The additive dramatically affected the hydrodynamics of the falling film and a droplet flow regime was evident for testing at all tube spacings. The mechanical mixing of the advanced surfaces increased the mass transfer to about 75% of that observed on a smooth tube bundle, tested with heat and mass transfer additive. Testing with heat and mass transfer additive and advanced surfaces demonstrated a synergistic effect which doubled the mass absorbed from that observed with only the advanced surface. The overall film-side heat transfer coefficient for the advanced tube bundles doubled with the addition of 500-wppm of 2-ethyl-1- hexanol. « less
Leaf Diffusion Resistance Responses of Three Petunia Cultivars to Ozone and/or Sulfur Dioxide

The response of stomata to 03 and/or S02 in two humidity regimes was evaluated in terms of leaf diffusion resistance (LDR) of petunia (Petunia hybrida Vilm.) plants of three cultivars of differing 03 sensitivity. At about 50% relative humidity, exposure to 03 or 03 and S02 resulted in rapid increases in LDR with the fastest response in the mixture. There were only slight increases in LDR with 03 or 03 and S02 exposure at about 90% relative humidity and there were only slight effects of S02 alone on LDR at either 50% or 90% relative humidity. The LDR of the sensitive cultivar ’White Cascade’ increased most rapidly in 03 alone and the least sensitive ’Capri’ most rapidly in the 03 and S02 mixture but the maximum LDR reached with continued exposure was similar for all cultivars.
Experimental verification of a modified scaling group for spontaneous imbibition

Spontaneous imbibition is of critical importance to oil recovery from fractured reservoirs. A widely used approach to prediction of oil recovery involves scale-up of laboratory results to reservoir conditions. Scaling involves the effects of sample size, shape, boundary conditions, viscosity and viscosity ratios, interfacial tension, pore structure, wettability, capillary pressure and relative permeability. This work addresses the problem of scaling the combined effects of sample shape, boundary conditions, and viscosity ratios with only minor variations in other parameters. Imbibition measurements are presented for cylindrical Berea Sandstone cores of different lengths. For some experiments, core surfaces were partially sealed with epoxy to give different boundary conditions. Cores were initially saturated with refined mineral oils of different viscosities. A synthetic reservoir brine was used as the wetting phase. A characteristic length was defined as the square root of the ratio of volume to the summation of the ratios of area of core surface open to imbibition to the corresponding distance from the surface to the no-flow boundary. The characteristic length, in combination with a term that compensates for the effect of viscosity ratio, gave close correlation of all data.
Asphaltene Adsorption Onto Formation Rock: An Approach to Asphaltene Formation Damage Prevention

In this paper, through a comparative study on Static vs Dynamic adsorption of asphaltene onto formation rock, it is reported how, for the particular asphaltene/formation rock system here considered, the Dynamic asphaltene adsorption onto formation rock is a continuous phenomenon by which the quantity of adsorbed asphaltene increases continuously. In the authors` opinion this rather remarkable adsorption behavior may contribute to asphaltene formation damage. In the hypothesis that prevention may represent a more economical approach than removal, in this work is also reported a possible prevention approach based on formation rock treatment by means of specific chemicals more apt than asphaltenes to be adsorbed onto rock. As preliminary demonstration, with the aim at assessing qualitatively the potential of their approach, the authors have pre-treated the rock by means of commercially available asphaltene dispersant and flocculation inhibitors. Albeit the chosen additives are not commercialized on the base of their specific adsorption feature, a prevention effect has been effectively found. Experimental set ups and procedures used as a base for a test able to rank chemicals with respect to their asphaltene adsorption inhibitive effects are also reported.
Comparative Analysis of Nutritional and Anti Nutritional Contents of Some Varieties of Mango (Mangifera indica) in Kaduna Metropolis-Nigeria

Three varieties of mangoes (Mangifera indica) namely; Adansonia digitata (Durshea) big seed, Durio zubethinus murr (Peter) middle seeded, Foetide lour (Julie) collected within Kaduna metropolis were subjected to proximate analysis. Analysis of the nutritional and anti-nutritional contents of the three varieties of mangoes revealed that moisture content, crude protein, carbohydrate, crude fat, ash content and vitamin c were 79.17, 1.97, 7.16, 1.89, 9.81 and 34.12% respectively for Durshea variety. The findings revealed that Peter (Middle Seeded) mango proximate values for all the nutrients analyzed were not significantly (p>0.05) different from the values obtained from Durshea result. The Julie (Small Seeded) mango's moisture content (72.04%) and carbohydrate contents (16.59 mg/100 g) were significantly (p<0.05) different from Durshea and Peter varieties. The findings also revealed that calcium contents were 0.15, 0.10 and 0.13% for durshea, peter and Julie, respectively. Iron and magnesium contents were present in small amount for all the three variaties. The contents of cyanogenic glycosides (0.28 mg/100 g), oxalates (1.60 mg/100 g) and phytate (0.62 mg/100 g) for durshea were not significantly different from peter and jullie varieties of the mango. The findings revealed that the three varieties of mango contain appreciable amounts of nutrients that the body required for its normal metabolic functions . The anti nutrients contents is negligible. The Durshea variety is the most recommended for human consumption because of its high lipids and calcium contents.
HEAT AND MASS TRANSFER IN IMPINGEMENT DRYING

ABSTRACT In industrial drying applications, efficient transfer of heat and mass between a drying medium and the material being dried is very critical for the overall economics of the operation. Impinging jets are therefore widely used for their enhanced tmnsport characteristics, especially for drying of continuous sheets of materials such as paper and textiles. In such applications, a thin sheet of material, as wide as 6m in cross machine direction, speeds at velocities as high as 90 km/hr under high velocity jets emerging from a confining surface parallel to the material surface. Many variables and effects need to k considered for proper design of such impinging jet systems: nozzle geometry and size, nozzle configuration, location of exhaust pons, nozzle-to-surface separation, jet-to-jet separation, cross flow, jet exit velocity and surface motion. For permeable materials, additional enhancement of heat and mass transfer that occur when some of the impinging gas is removed through the material makes this.
Thermodynamic Prediction of Paraffin Wax Precipitation in Crude Oil Pipelines

Abstract Crude oils are generally very complex chemical systems consisting predominantly of hundreds to thousands of hydrocarbon compounds from simple low-molecular-weight paraffins to high-molecular-weight waxes. At low temperatures these paraffins precipitate as a wax phase, which may cause the plugging of pipes and many other problems. In this study the cloud point and the amount of the precipitated wax at different temperatures were determined using a modified multi-solid wax model at stock tank conditions and at high pressure for three live crudes and synthetic oil. The model is based on the description of the nonideality of the phases in equilibrium using the Peng-Robinson cubic equation of state for the liquid phase with a modified a-function and the universal quasi chemical (UNIQUAC) equation for the solid phase, which takes into account the effects of temperature, pressure, and composition on the wax precipitation. The model assumes the crystalline nature of wax formed. The experimental data and model predictions reveal that the cloud point decreases with increased pressure and increases when the crude oil is mixed with more light hydrocarbons. The values predicted by the new model show very little deviation from experimental data.
The crystal structures of low chalcocite and djurleite

Low chalcocite is monoclinic, space group P2Ifc, with a unit cell having a = 15.246(4)A, b = 11.884(2)A, c = 13.494(3) A, P = 116.35(1t, and containing 48 Cu2S. Its structure was solved by the symbolic addition method, using 5155 independent intensity data measured with MoKcx radiation on an automatic diffractometer. Refinement in anisotropic mode led to R = 0.086. The structure is based on hexagonal-close-packed frame- work of sulfur atoms, with copper atoms occupying mainly triangular interstices. Of the 24 different copper atoms, 21 form triangular CUS3groups, and one is in a distorted CUS4tetrahedron. Djurleite is monoclinic, space group P2Ifn, with a unit cell having a = 26.897(6) A, b = 15.745(3)A, c = 13.565(3) A, P = 90.13(3t, and con- taining 8 CU31S16' The structure was solved by extending the known substructure phases by the symbolic addition procedure, using 5686 inde- pendent intensity data measured with MoKcx radiation. Refinement con- verged at R = 0.116. The structure is similar in general to the low chalcocite structure, but of the 62 different copper atoms, 52 form triangular groups, 9 form distorted tetrahedral groups, and one is in unique linear twofold coordination. Both structures are derived from the high chalcocite structure (P 63/mmc, a = 3.96 A, c = 6.72 A, cell content = 2 Cu2S) which forms a substructure corresponding to the hexagonal-close-packed sulfur framework, but the details of the copper arrangement are entirely different in the two phases. The average Cu - S bond length in the CUS3triangles is 2.32 A in low chalcocite and 2.29 Ain djurleite. The overall average Cu - S distance in the tetrahedra is 2.48 A, but varies from 2.22 to 2.91 A. Each copper atom has from 2 to 8 other copper atom neighbors less than 3.0 A distant, varying up from 2.45 A through a maximum clustering at about 2.78 A. CU- Cu bonding interaction is probably significant but is not clearly understood. * Dedicated to Prof. W. Nowacki on occasion of his 70th birthday
Composição química da chuva e aporte atmosférico na Ilha Grande, RJ

Wet (n = 21) and dry (n = 23) deposition samples were collected from March to September 2002 at the southern coast of Ilha Grande. Rainwater pH varied from 4.3 to 6.3 and ionic concentrations (in µmol L-1) decreased in the order Cl- > Na+ > Mg2+ > SO42- > NO3- ~ NH4+ > K+ ~ H+ > Ca2+. Scavenging of sea-salt aerosols was the major source of Cl-, Na+, Mg2+, and Ca2+. Half of total SO42- was non-sea-salt SO42-. Total deposition fluxes of NH4+, NO3-, and non-sea-salt SO42- were respectively 9.3, 17.8, and 16.0 mol ha-1 month-1.
Thermal conductivity of wool and wool–hemp insulation

Measurements have been obtained for the thermal resistance of sheep‐wool insulation and wool–hemp mixtures, both in the form of bonded insulation batts, using a calibrated guarded hot‐box. The density was 9.6–25.9 kg m−3 for the wool and 9.9–18.1 kg m−3 for the wool–hemp mixtures. The measurements were made at a mean sample temperature of 13.3°C using a calibrated guarded hot‐box. The estimated uncertainly in the resistance measurements was of the order of ±7%. The thermal conductivity of the samples, derived from the thermal resistance measurements on the basis of the measured thickness, was well correlated with the density, although the variation with density was larger than that obtained in previous studies. The conductivity of the wool–hemp samples was not significantly different from that of the wool samples at the same density. Moisture uptake produced an increase of less than 5% in the conductivity of the bonded wool insulation for an increase in absorbed moisture content of 20%. The thermal resistance was 1.6% lower on average for samples oriented in the horizontal plane rather than the vertical plane, but this difference is not significant. Copyright © 2005 John Wiley & Sons, Ltd.
Climate dependence of the CO2 fertilization effect on terrestrial net primary production

The quantitative formulation of the fertilization effect of CO2 enrichment on net primary production (NPP) introduced by Keeling and Bacastow in 1970s (known as Keeling’s formula) has been recognized as a summary of experimental data and has been used in various assessments of the industrial impact on atmospheric chemistry. Nevertheless, the magnitude of the formula’s key coefficient, the so-called growth factor, has remained open to question. Some of the global carbon cycle modelers avoid this question by tuning growth factor and choosing the value that fits the observed course of atmospheric CO2 changes. However, for mapping terrestrial sinks induced by the CO2 fertilization effect one needs a geographical pattern of the growth factor rather than its globally averaged value. The earlier approach to this problem involved formulating the climate dependence of the growth factor and the derivation of its global pattern from climatic variables (whose geographical distribution is known). We use a process-based model (TsuBiMo) for this purpose and derive the values of growth factor for major biomes for comparison our approach with the earlier studies. Contrary to the earlier prevailing opinion, TsuBiMo predicts that these values decrease with mean annual temperature (excluding biomes of limited water supply). We attribute this result to the effect of light limitation caused by mutual shading inside a canopy, which was considered earlier as unimportant, and conclude that current hypotheses about CO2 fertilization effect (and thus projections of the related carbon sink) are very sensitive to the choice of driving forces taken into account.
Accumulation of heavy metals in soil and paddy crop (Oryza sativa), irrigated with water of Ramgarh Lake, Gorakhpur, UP, India

Heavy metals, a highly polluting group of constituents known to exert adverse effects, tend to accumulate in living organisms. The objective of this study was to determine the accumulation and translocation of heavy metals in soil and in paddy crop irrigated with lake water compared to soil and paddy crop irrigated with bore-well water. The quantities of heavy metals (Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg) were determined in different parts of rice plants (Oryza sativa). Results revealed that the mean levels of soil Cd, Cr, Pb, Zn, As, Mn, and Hg in experimental soil and in different parts of rice plant (root, straw, and grain) were higher than the control except for Cu. The content of eight toxic metals was significantly higher in root than in aerial parts of the rice (straw and grains). Rice roots were enriched in Cd, As, Hg, and Pb from the soil, while Cr, Cu, Zn, and Mn were hardly taken by the roots. Bioaccumulation factor for Hg was significantly higher than other heavy metals. Metal transfer factors from soil to rice plants were significant for Cd, Cr, Cu, Pb, Zn, As, Mn, and Hg. The concentrations of metals in lake water were found to be within the permissible limit of Indian standard prescribed by Central Pollution Control Board (2000), except for Hg and As, which were higher than the limit of Indian standard. However, the concentrations of heavy metals in soil and rice grains were still below the maximal levels, as stipulated by Indian Prevention of Food Adulteration Act (PFA, 1954) and World Health Organization (WHO, 1993) guidelines.
ON BOUNDARY LAYER STAGNATION POINT FLOW OF A NANOFLUID OVER A PERMEABLE FLAT SURFACE WITH NEWTONIAN HEATING

This study investigates the boundary layer stagnation point flow of a nanofluid past a permeable flat surface with Newtonian heating. The model used for the nanofluid is the one that incorporates the combined effects of Brownian motion and thermophoresis. Using a local similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically by applying the shooting iteration technique together with a fourth-order Runge-Kutta integration scheme. Graphical results for the dimensionless velocity, temperature, and nanoparticle concentration distributions are shown for various values of the six thermophysical parameters controlling the flow regime: Prandtl number Pr, Lewis number Le, convection Biot number Bi, the Brownian motion parameter Nb, the thermophoresis parameter Nt, and the suction/injection parameter β. The expressions for the local skin friction, reduced Nusselt number, and reduced Sherwood number were obtained numerically and are discussed quantitatively.
Exploring new methods and materials for enantioselective separations and catalysis

In this article, we will review and highlight some recent computational work on enantioselective adsorption and catalysis in zeolites and metal–organic frameworks. The design, development and understanding of chiral structures will help expand the utility of nanoporous materials into chiral technology. The highlighted works are examples of how molecular simulations can provide a fundamental understanding of chirality in nanoporous materials. This understanding is essential to help in the design and development of next-generation enantioselective separation devices and catalysts.
Interfaces between lanthanum hexaaluminate and sapphire studied by high-resolution electron microscopy

Abstract Thin films of lanthanum hexaaluminate were produced on the basal plane of sapphire by chemical solution deposition and thermal treatment. The close-packed oxygen sublattices of the lanthanum hexaaluminate films with the magnetoplumbite structure and the sapphire are in exact topotactic alignment. The structure of the interfaces were investigated by high-resolution electron microscopy, and the images of focus series were used to invert the imaging process and finally to reconstruct the complex electron exit wave at the object plane. Simulated electron waves based on different interface models were compared with the reconstructed waves, and very good matches of the phase images were obtained. Two different types of interface were observed and were characterized in detail along [1100]HA-[21 10]s (where the subscript HA indicates the lanthanum hexaaluminate and the subscript S sapphire). Using criteria of structural chemistry, possible stacking sequences of the oxygen sublattices across the boundary were determined and two models of unrelaxed interfaces were derived. The type I interface is located at a common oxygen plane of sapphire and a mixed layer of tetrahedral and octahedral cation sites of the spinel block of hexaaluminate. The type II interface is positioned at a partially occupied aluminium layer between the mirror plane of the hexaaluminate and an oxygen plane of the sapphire. It was found that the structural elements at the two interfaces agree with the structural features of known aluminium oxides, which is realized by an appropriate stacking seauence of the oxygen sublattices at the interface and the non-occupation of unfavoured sites.