Miracle-dz/UniFAR-FTUs huggingface dataset:
Heat transfer to a supercritical pressure fluid flowing in sub-bundle channels

Supercritical pressure water cooled reactor (SCWR) has been regarded as an innovative nuclear reactor. For the design and development of the SCWR, heat transfer performance under supercritical pressure is one of the most important indicators. In this paper, experimental data are presented on the heat transfer to a supercritical pressure fluid flowing vertically upward and downward in a small diameter heated tube and two sub-bundle channels with three heater rods and seven heater rods, using HCFC22 as the test fluid. Downstream of grid spacer for the sub-bundles, heat transfer enhancement was observed in the upward flow, but not in the downward flow. The enhancement was remarkable especially when the heat transfer deterioration occurs in the fully developed region unaffected by the spacer. The heat transfer correlation for the downstream region of the spacer was developed in the normal heat transfer of sub-bundles. In the fully developed region for the sub-bundle, occurrence of the heat transfer deterioration was suppressed or degree of the deterioration was moderated. At high mass velocity for downward flow in the seven rod sub-bundle, oscillation of heat transfer was observed in the region of the enthalpy over the pseudocritical point.
Formation and stability of multilayers of polyelectrolytes.

Sequential addition of anionic and cationic polyelectrolytes may lead to the formation of multilayers at a solid surface. The buildup of such multilayers is characterized by a stepwise increase of the adsorbed amount and layer thickness and by alternating highly positive and highly negative values for the ζ-potential. The prime variables which determine the stability of these structures are the polymer charge and the ionic strength. Very stable multilayers are formed when both polymers are highly charged and when the ionic strength is low. For weakly stable multilayers complexation at the surface may first occur, followed by desorption of the complexes. For strongly charged polyelectrolytes the charge stoichiometry, which is not always 1:1, seems to be unique for each pair of polyelectrolytes; no influence of the substrate, of the pH, or of the ionic strength could be observed.
Ion bombardment induced ripple topography on amorphous solids

Abstract Earlier studies of the ion bombardment induced ripple morphology on the surfaces of amorphous solids when compared with geomorphological effects are shown to possess many similar features. The present study, with 40 keV Ar+ ion bombarded Si suggests that analogies are incomplete, however, and that greater similarities with the process of macroscopic sandblasting (corrasion) exist. It is shown that the genesis of wave like structures on Si is from isolated features, which have the appearance of ripple trains, which are faceted. It is suggested that these features result from particle flux enhancement processes near surface dimples generated by stress induced surface lifting.
Combinatorial One‐Pot Synthesis of Poly‐N‐acetyllactosamine Oligosaccharides with Leloir‐Glycosyltransferases

Poly-N-acetyllactosamine (Poly-LacNAc, [3Galβ1,4GlcNAcβ1]n) glycans play an essential role in carbohydrate-protein interactions. The synthesis of poly-LacNAc, both chemical and enzymatic, is typically characterized by high losses of product during sequential synthesis, due to deprotection and/or purification steps. In this work we present a one-pot synthesis of poly-LacNAc oligosaccharides by combining recombinant glycosyltransferases. By fractionation of the poly-LacNAc glycan mixture we were able to isolate glycans with up to six N-acetyllactosamine (LacNAc) units. Activity measurements of the involved recombinant β1,4-galactosyltransferase-1 (β4GalT-1) and β1,3-N-acetylglucosaminyltransferase (β3GlcNAcT) with isolated glycan substrates of up to eight sugar units revealed a preference of β3GlcNAcT for the tetrasaccharide and no preference of β4GalT-1 for a specific glycan length. These findings led us to the optimization of combinatorial one-pot synthesis by variation of substrate and enzyme ratios, as well as starting the synthesis with various poly-LacNAc chain lengths. Consequently, we present here an optimized poly-LacNAc synthesis by the combination of two glycosyltransferases and a uridine-diphospho-glucose/N-acetylglucosamine 4′-epimerase as one-pot strategy resulting in long poly-LacNAc glycans with up to six LacNAc units in high yields while minimizing reaction time and product loss. The obtained products are important ligands for the biofunctionalization of biomaterial surfaces and the construction of an artificial extracellular matrix for tissue engineering.
Modeling free and supported metallic nanoclusters: structure and dynamics

We compare atomic structure and dynamics of free and supported metallic clusters via molecular dynamics simulations using tight-binding semiempirical potentials for metal–metal interactions and a potential fitted to ab initio calculations for the metal-supported ones, the support being essentially the MgO(100) surface in the case of a nonreactive metal–oxide interface. The structural transition for free Ni, Pd, Pt, Cu, Ag, Au clusters with noncrystalline structures (mainly icosahedral and decahedral) at small sizes to FCC truncated octahedrons for larger sizes is reported as well as the variation of the critical size of transition from 3d to 5d metals. In the case of Pd clusters on the MgO(100) surface, we analyze the substrate-induced modifications in morphology and atomic structure and follow their evolution as a function of cluster size. The mechanism of strain release by misfit interfacial dislocations in 3D clusters is described at the atomic level. Dynamics of growth and melting of free silver clusters are discussed and some effects of the oxide substrate in melting transition are pointed out, notably the delay in melting induced by the epitaxial relation with the support.
Effect of pressure on bonding in black phosphorus

The bond lengths and bond angles of orthorhombic black phosphorus have been determined as a function of hydrostatic pressures to 26.6(5) kbar using time‐of‐flight neutron powder diffraction. We show that the markedly anisotropic compression reported previously results from a large pressure‐induced shortening of the van der Waals bonds separating layers of atoms combined with a shear motion within the layers. Covalently bonded chains of atoms along the a direction remain very rigid. The average effective linear compressibility for van der Waals bonds is 1.48(9) ×10−3 kbar−1 while the average effective linear compressibility for covalent bonds is an order of magnitude smaller, 2.6(8) ×10−4 kbar−1.
EFFECT OF VESICULAR‐ARBUSCULAR MYCORRHIZAL FUNGI ON THE RELATIONS OF PLANT GROWTH, INTERNAL PHOSPHORUS CONCENTRATION AND SOIL PHOSPHATE ANALYSES

Summary The effect of infection by vesicular-arbuscular mycorrhiza on the predictive value of soil analysis for available P was tested in a glasshouse experiment. Leeks (Allium porrum) were grown on ten Rothamsted soils with a wide range of initial NaHCO3-soluble P, each of which also received 5 levels of added P. Soils were partially sterilized with 1 Mrad of γ-radiation, or left untreated; plants on sterilized soil were infected with yellow-vacuolate endophyte (Glomus mosseae) or left non-mycorrhizal. The NaHCO3-soluble P in the soils was measured 5 days after phosphate addition. Yields from all P levels on all soils were plotted against soil NaHCO3-soluble P content and separate smooth response curves were obtained for non-infected and artificially-infected plants. Infection increased yield only on soils with less than 100 mg P kg−1. In contrast, naturally-infected plants gave no clearly defined response curve to P, and on three soils the yields were consistently low. These soils gave very low natural infections and had low spore densities probably due to the cropping history of the sites. Artificially-infected plants had much higher shoot P concentrations than did uninfected plants of similar dry weight, over a large range of soil phosphate levels; this effect was also noted with the endophyte G. fasciculatus. Naturally-infected plants showed a poor relationship between shoot P concentration and yield.
Natural convection heat transfer in thermally stratified liquid metal.

Natural convection tests were conducted using Pb-Bi alloy, with the view to evaluating the effects brought by thermal stratification in liquid metal on the natural convection heat transfer along an immersed vertical metal surface. The vertical metal surface was represented by a stainless steel plate 300 mm high, placed in a cylindrical vessel 400 mm in diameter filled with molten Pb-Bi. The experiment was performed with the heat flux of the plate surface maintained constant and uniform. The temperature distribution through the liquid metal filling the vessel was controlled by regulating a flow of air blown onto the vessel surface; temperature measurements were made by means of a traversing thermocouple. For the case of unstratified bulk fluid, the values obtained for heat transfer rate agreed well with corresponding data given by Sheriff for Na. With increasing degree of stratification, the thickness of the boundary layer decreased in keeping. The resulting increase of heat transfer rate indicated a defin.
Viable and Rapid Determination of Organochlorine Pesticides in Water

Vortex-assisted liquid-liquid microextraction (VALLME) procedure was developed for the determination of different organochlorine pesticides (OCPs) in water samples by GC-MS. After the determination of the most suitable extraction solvent and rotational speed of the vortex, parameters such as vortex extraction time, solvent volume, ionic strength of the sample were optimized by using a 2 3 factorial experimental design. The optimized extraction conditions for 5 mL water sample were as follows: extraction solvent, bromoform; solvent volume, 50 μL; vortex extraction time, 2 min at 3000 rpm with no ionic strength adjustment, centrifugation 5 min at 4000 rpm. Limits of detection (LODs) and quantification (LOQs) were in the range of 0.011-0.052 and 0.037-0.173 μg/L, respectively. Mean recoveries of OCPs from fortified water samples are 96% for three different fortification levels between 0.1 and 5 μg/L and relative standard deviations of the recoveries are below 6%. The performance of the developed method was compared with traditional liquid-liquid extraction on real water samples including tap water, well water, surface (lake and stream) water, municipal wastewater, and treated municipal wastewater and comparable extraction efficiencies were obtained. The proposed VALLME procedure requires small volumes of solvent and water sample. It is viable, rapid, and easy to use for the determination of OCPs in water samples by using GC-MS.
Study on Unsteady Combustion Behaviors of AP/HTPB Base‐Bleed Propellants under Transient Depressurization Conditions

As the base-bleed projectile flies out of the muzzle, the environmental pressure in the base-bleed combustion chamber suddenly decreases and AP/HTPB base-bleed propellant suffers intense unsteady combustion. To further study the unsteady combustion characteristics of base-bleed propellants, a semi-closed bomb as was designed experimental device and transient depressurization conditions of the muzzle were simulated. Measurements of the transient combustion characteristics of the base-bleed propellant under high depressurization rate were carried out by using a high speed digital camera system. In the experiments, the combustion chamber pressure of the semi-closed bomb was controlled from 20 to 90 MPa and the depressurization rate was controlled from 400 to1.12×104 MPa s−1. The experimental results indicate that, the out-of-phase blowing effect is intense under rapid depressurization condition, leading to the reaction layer thickened. The thermal feedback to the solid surface decreases and thus the combustion reaction of gas phase is so difficult to maintain that it begins to extinguish. However, the thermal decomposition of the solid phase is still continuing and a yellow fog can be observed above the combustion chamber nozzle. Depending on the maximum pressure in the combustion chamber and depressurization rate, the transient combustion behavior of AP/HTPB base-bleed propellant displays three patterns, i.e., automatic reignition, oscillating combustion (a critical type) and permanent extinguishment. Three unsteady combustion behaviors are preliminarily analyzed based on the thermal feedback. If the initial pressure in the combustion chamber before depressurization is larger or the depressurization rate is smaller, the base-bleed propellant tends to automatically reignite earlier and the combustion process is more stable.
Synthesis and surface characteristics of silica– and alumina–carbon composite xerogels

Silica– and alumina–carbon composite xerogels were obtained by the sol–gel method and carbonization of the product obtained at 773 and 1173 K in inert atmosphere. Samples so obtained were characterized by CO2 adsorption at 273 K and by mercury porosimetry, X-ray diffraction and scanning electron microscopy. With these techniques the surface area and porosity of the samples were determined, as well as the nature of the inorganic component of the composite and the morphology of the surface. The acid–base surface characteristics of the samples were studied by the decomposition reaction of isopropanol. The Al2O3-containing samples had more developed meso- and macroporosity than the SiO2-containing ones. The surface areas obtained for the carbonized derivatives varied between 300 and 400 m2 g−1. Alumina–carbon composite xerogels were much more acidic than the silica–carbon composite xerogels. Due to this difference, the electronic interaction between the carbonaceous component, with basic character, and the alumina in the composite xerogels caused a decrease in the total surface acidity of the composite. This electronic interaction increased with the treatment temperature.
Iron sources in relation to leaf senescence in French bean (phaseolus vulgaris L.)

Abstract Pot and field experiment were conducted to study the effects of three iron sources, viz., Fe‐EDTA, Fe‐EDDHA and FeSO4 on the yield of french bean (Phaseolus vulgaris L.). The natural available iron in the soil was 2–4 ppm. All the iron sources in general, induced a significant increase in chlorophyll ‘a and b’, and indole‐3‐acetic acid components of french bean when used at a concentration of 5 to 10 mg kg‐1 soil. Remarkably, these favourable acquisitions were more prominent in the cases of Fe‐EDDHA (@ 5 mg kg‐1 soil) and Fe‐EDTA (@ 5 mg kg‐1 soil) treatments, while a double dose of FeSO4 (@ 10 mg kg‐1 soil) was required to induce a parallel change in the characteristics noted above. A critical individual assessment of the effects of the first two iron sources obviate the fact that Fe‐EDDHA is superior most in inducing a delayed senescence and the related characteristics of applied importance. These effects were significantly better over those induced by the corresponding concentrations of Fe‐EDT.
DNA molecular motors

Due to its simple and predictable molecular recognition chemistry, DNA is a versatile self-assembly molecule. Two strands of DNA most strongly bind together to form a double helix only when their base sequences are complementary. Here we show how this construction rule can be used to induce nanoscale motion. In particular, we have devised two DNA-based molecular motors powered by DNA. Both consist of two double-stranded arms held together at one end by a single-stranded flexible hinge. One motor, referred to as molecular tweezers, has two single-stranded extensions at the ends of the arms, which serve as handles used to pull the tweezers shut. The tweezers are closed when a particular piece of single-stranded DNA, called the fuel strand, hybridizes with the handles. In the other motor, referred to as an actuator, the single-stranded extensions are joined together so that the motor forms a loop-like structure. The fuel strand hybridizing with the actuator pushes the two arms apart. Both motors are returned to their original configuration by a removal strand which binds to a single-stranded overhang of the fuel strand and then removes the fuel strand from the motor strand by the process of branch migration.
Properties of Palm Oil-in-Water Emulsions Stabilized by Nonionic Emulsifiers

Palm oil-in-water emulsions prepared using various ethoxylated nonionic emulsifiers were studied with respect to the effect of concentration and type of the selected emulsifiers, and the emulsification process itself on the properties of the emulsions obtained. The stability of the emulsion during storage was monitored. The physical properties were characterized by particle size analysis, turbidity, interfacial tension, and electrophoretic mobility measurements. Results show that emulsion stability was strongly dependent upon the types of palm oil and emulsifier used and their concentrations. Stable emulsions with minimal creaming at room temperature for up to 6 months can be prepared with the right choice of emulsifier and under the correct conditions of emulsification. The influence of the interfacial layer of emulsifier on emulsion stability is discussed.
Hydrated lime reaction with hcl under simulated flue gas conditions

Hydrochloric acid (HCl) is a common acidic pollutant present in the flue gas of most municipal and hazardous waste incinerators. Hydrated lime [Ca(OH)2] is often used as a sorbent to remove HCl through the dry and semidry scrubbing process. However, this process provides a very short residence time for the lime and HCl to react, causing the lime conversion efficiency to be low and generating a large amount of fly ash. Following our previous studies on the kinetics of the HCl−lime reaction, the current paper is aimed at the investigation of the effects of other species present in the flue gas, namely, CO2, SO2, and moisture, on the HCl−lime reaction. The reaction was carried out in a thermogravimetric analyzer at a temperature of 200 °C under 9% of O2, and the products of the reaction were identified and quantified using X-ray diffraction. The sequential reactions of lime with CO2 (or SO2)−HCl−CO2 (or SO2) were also conducted to compare the different effects of these species on the formation of product lay.
Optical and Thermal Studies on Lyotropic Chromonic Liquid Crystals in Nematic and Biphasic Regions

A binary mixture of abietic acid and orthophosphoric acid (H3PO4) exhibits coexistence of biphasic region of Nematic + Isotropic (N + I), lyotropic Nematic (ND), and Smectic-G (SmG) phases. The mixture exhibits N + I, N and SmG phases at different concentrations and at different temperatures. Mixtures with all concentrations of abietic acid exhibit I→N + I→N→SmG phases sequentially when the specimen is cooled from its isotropic melt. These phases have been characterized by using differential scanning calorimetric, X-ray diffraction, and optical texture studies.
Optimization of Fenton oxidation process for treatment of hexogeon industrial wastewater using response surface methodology

AbstractFenton oxidation technology was applied to treat hexogeon industrial wastewater and response surface methodology was used to optimize the effects of the FeSO4 concentration, H2O2 concentration, pH value, and temperature. A quadratic model was obtained as the result of this design. In the optimization, the coefficient of variation is only 3.17%, indicating a good precision and reliability of the experimental. The coefficient of association (R2) and adj-R2 for quadratic model were evaluated quite satisfactorily as 0.98 and 0.96, respectively. The predicted optimum conditions were determined as 763 mg L−1 of FeSO4 concentration, 107 mg L−1 of H2O2 concentration, 2.64 of pH, and 19°C with 83.5% of chemical oxygen demand removal. The experimental result was 82.92% under optimizing reaction factors.
Modeling Dry Deposition of Aerosol Particles onto Rough Surfaces

Dry deposition is a primary mechanism by which suspended particles are transported from gas onto surfaces. Prediction of this transport rate is needed in a vast range of applications, including environmental, industrial, and engineering, and in studying the impacts of aerosols. Besides air flow characteristics and properties of aerosol particles, the dry deposition velocity depends greatly on surface properties. However, existing models describe rough surfaces with only one parameter, the surface roughness height, and are therefore of limited accuracy. Here, we introduce a new, and yet simple, physical approach to account for the influence of surface roughness on the dry deposition velocity. The approach relies on a hybrid parameter that combines the surface roughness height and the peak-to-peak distance between roughness elements. Our new approach is able to predict the deposition velocity accurately, being superior to many of the earlier models, which overpredict deposition velocities by a factor as high as 25. In addition, our approach is more general and covers a wide size range of aerosol particle diameter (0.001–100 μm). Copyright 2012 American Association for Aerosol Research
A Novel Alternative Method for Modeling the Effects of Air Temperature and Slice Thickness on Quality and Drying Kinetics of Tomato Slices: Superposition Technique

The effect of air temperature (AT) and slice thickness (ST) on the quality and drying kinetics of tomato slices were studied. The drying period of tomato slices to reach the moisture content of 15% (wb) ranged from 2.6 to 18.7 h. The water diffusivity, activation energy, and resistance to diffusion ranged from 1.4 × 10−10 to 2.8 × 10−9 m2/s, 21.25 to 23.4 kJ/mol, and from 939 to 4590 m2 s/kg, respectively. Drying had a significant effect on ascorbic acid, soluble solid, acidity, and pH (P = 0.01). The ascorbic acid degradation was greatly influenced by ST. The results show that time-temperature superposition technique (TTST) was very efficient in the modeling of the drying process. The proposed TTST provides a novel alternative in curve-fitting exercise of drying data. Neural networks also showed favorable performance in estimating the drying functions.
The Importance of Asphaltene Content in Petroleum II—Multi-peak Viscosity Correlations

Abstract It is common knowledge in petroleum science and technology that viscosities of dead crude oil are monotonic functions of oil's asphaltene content. However, analysis of crude oil databases reveals multiple peaking of oil viscosity (up to two orders of magnitude) at specific asphaltene contents, close to structural phase boundaries observed in asphaltene and oil solutions. Due to strong viscosity-density correlation, maxima of viscosity practically coincide with earlier reported maxima of specific gravity in dead crude oils.