Amount Of Dilution Research Articles

Observation of a V-Shape Superconductivity Evolution on Tungsten-Intercalated 2H-Type Niobium Diselenide.

van der Waals-layered niobium diselenide (NbSe2) intercalated by d-electron transition metals is an ideal test bed for the exploration of their diversiform evolution of ground states. These intercalations are mostly viewed as ordered structures aligned with periodicities of their host materials that enable control of the electronic phases via gradually changing of intercalation ratios. Here, we present the structure and superconductivity in tungsten (W)-intercalated 2H-NbSe2 crystals, which reveals an order to disorder distribution of W atoms with increasing confined intercalating amounts, leading to an approximate V-shape suppression of superconductivity. Aided by density functional theory calculations, we demonstrate that the local magnetic moment around W intercalants induced by the charge redistribution gives rise to the quick superconductivity suppression in 2H-NbSe2 below a certain dilute amount (W% = 0.06). Simultaneously, W intercalants also induce structural aberration due to aggregation effects and inhibit the generation of an ordered structure in 2H-NbSe2, resulting in a recovery of its superconductivity. The alteration of structure and electronic phases in 2H-NbSe2 via intercalation of nonmagnetic transition metals in the van der Waals gap enables the exploration of combined magnetic quantum criticality, superconductivity, and other related electronic correlations.

Harnessing elastic instabilities for enhanced mixing and reaction kinetics in porous media

Turbulent flows have been used for millennia to mix solutes; a familiar example is stirring cream into coffee. However, many energy, environmental, and industrial processes rely on the mixing of solutes in porous media where confinement suppresses inertial turbulence. As a result, mixing is drastically hindered, requiring fluid to permeate long distances for appreciable mixing and introducing additional steps to drive mixing that can be expensive and environmentally harmful. Here, we demonstrate that this limitation can be overcome just by adding dilute amounts of flexible polymers to the fluid. Flow-driven stretching of the polymers generates an elastic instability, driving turbulent-like chaotic flow fluctuations, despite the pore-scale confinement that prohibits typical inertial turbulence. Using in situ imaging, we show that these fluctuations stretch and fold the fluid within the pores along thin layers ("lamellae") characterized by sharp solute concentration gradients, driving mixing by diffusion in the pores. This process results in a [Formula: see text] reduction in the required mixing length, a [Formula: see text] increase in solute transverse dispersivity, and can be harnessed to increase the rate at which chemical compounds react by [Formula: see text]-enhancements that we rationalize using turbulence-inspired modeling of the underlying transport processes. Our work thereby establishes a simple, robust, versatile, and predictive way to mix solutes in porous media, with potential applications ranging from large-scale chemical production to environmental remediation.

Surface-Functionalized Nano-Montmorillonite and Its Application as Crude Oil Flow Improver

In view of the problem of poor flowability in the production and transportation of high-wax crude oil and high-viscosity crude oil, crude oil flow improvers are commonly used to reduce their viscosity and pour point. Although polymer-based crude oil flow improvers are highly effective in improving crude oil flowability, there are still problems such as high cost and the need for a large amount of solvent dilution when used. In this work, highly dispersed organic modified nano-montmorillonite was prepared by using Na-based montmorillonite and quaternary ammonium salts, and the influencing factors on the viscosity of the crude oil were investigated. The most effective modified nano-montmorillonite (B@MMT) can reduce the viscosity by 96.7% (21 °C) and depress the pour point by 15 °C. Furthermore, it has shown a high improvement in flowability in the other four different sources of crude oil, with viscosity reduction rates of 52.2, 93.4, 79.1 and 67.4%, respectively. B@MMT was characterized by FTIR, SEM, zeta potential and contact angle. Based on DSC and wax crystal structure analysis, the mechanism of the influence of B@MMT on crude oil viscosity and pour point was explored. Finally, the cost of B@MMT was estimated, and the result shows that, compared with the crude oil flow improver in use, B@MMT has considerable commercial competitive advantages.

Investigating laser power in AM-LMD process on the Inconel 718 powder deposited profile microstructure, aiming to repair gas turbine blades

ABSTRACT The purpose of this study was to evaluate the feasibility of repairing defective turbine blades made of Inconel 738 using additive manufacturing called laser metal deposition with the use of Inconel 718 powder. The deposition process was conducted on substrates using varying laser power, 150, 250 and 350 (W). The experimental results indicate that as the laser power is raised, there is a corresponding increase in the average of substrate melting depth, 33.42–405.12 (µm), the average of interface thickness, 2.85–10.20 (µm) and the amount of dilution, 0.036–0.684 (%). The substrate's volume percentage and the average size of the γ’ phase exhibit larger values prior to the deposition procedure compared to the subsequent stages. The augmentation of laser power resulted in a proportional rise in both the volume percentage and average size of the γ’ phase within the substrates. At the location near the interface of the first layer, graining is preferentially in the direction of heat transfer and crystal growth. A narrow unmixed zone was formed along the melting line in the substrate and first layer’s interface, that whit increased laser power, area of this zone decreased, 7.27 to almost 0 (µm). As the layers approach the surface, the grains become unidirectional and coaxial growth. Increasing the laser power increased the average grain size of the layers.

Impact of Dilute Amounts of Fission Products on the Mechanical Behavior of Ni.

Fission products may interact with structural materials in various nuclear energy applications and cause their mechanical performance to deteriorate. Therefore, it is important to study the effects of different fission products on the mechanical properties of structural materials. In this work, nickel was chosen as a model structural material system and dilute amounts of uranium and fission product impurities X = (Tc, Te, Sb, Ce, Eu, and U) up to 4 at % were used. Density functional theory (DFT) calculations were utilized to assess the effects of these substitutional impurities on the elastic behavior of the metal. Additionally, DFT was used to investigate some aspects of plastic response by computing the generalized stacking fault energies on the {111} ⟨112⟩ slip system for all alloying elements and at varying distances away from the stacking fault plane. None of the dopants satisfied the Pugh or Pettifor criteria for embrittlement, and alloying with Tc led to a slight increase in the elasticity of nickel. The phenomenon of Suzuki segregation was observed for all alloying elements, and there was consequently a significant reduction in the intrinsic stacking fault energy. Finally, and based on the analysis of the stacking fault energies, dopants generally led to softening the nickel (except for Tc and Ce), and all of the dopants were correlated with a loss of ductility (except Eu). These findings may be useful to consider in the design of next-generation reactors and nuclear waste management systems.

Improvement of the methods for determining ore losses when designing cement raw material deposit mining by surface miner combines

Relevance. The need to optimize production of cement raw materials and reduce the cost of processing raw materials. A surface miner combine allow high selective mining of a deposit, which helps to reduce moisture content of cement raw materials and reduce energy costs in a cement plant. In open-cast mining of cement raw materials deposits with the use of the surface miner combines, the increase in economic efficiency of mining operations can be achieved by determining the rational values of ore losses and dilution. Aim. To determine rational level of cement raw material losses during field development by surface miners. Objects. Cement industry quarries excavated with of the surface miner combines. Methods. Technical and economic analysis of the cement plant Beočin (Serbia), summation and synthesis of materials, sources and data available in the public domain, as well as calculations to determine the amount of loss and dilution of mineral resources at ore–rock contact for mining conditions of the quarry for extracting cement raw materials. Results. The main problems that arise during mining quarries for extracting cement raw materials have been identified. It concerns the determination of the volume of losses and dilution of mineral resources at the ore–rock contact for mining conditions of the quarry for extraction of cement raw materials. The authors present and substantiate conclusions about further effective application of optimal mining technology, with the use of the surface miner combines, which allows reducing the cost of production of minerals and specific operating costs of transporting carbonate rocks compared to the traditional technology of mining works at 50–60%.

Facet-Defined Dilute Metal Alloy Nanorods for Efficient Electroreduction of CO2 to n-Propanol.

Electroreduction of CO2 into liquid fuels is a compelling strategy for storing intermittent renewable energy. Here, we introduce a family of facet-defined dilute copper alloy nanocrystals as catalysts to improve the electrosynthesis of n-propanol from CO2 and H2O. We show that substituting a dilute amount of weak-CO-binding metals into the Cu(100) surface improves CO2-to-n-propanol activity and selectivity by modifying the electronic structure of catalysts to facilitate C1-C2 coupling while preserving the (100)-like 4-fold Cu ensembles which favor C1-C1 coupling. With the Au0.02Cu0.98 champion catalyst, we achieve an n-propanol Faradaic efficiency of 18.2 ± 0.3% at a low potential of -0.41 V versus the reversible hydrogen electrode and a peak production rate of 16.6 mA·cm-2. This study demonstrates that shape-controlled dilute-metal-alloy nanocrystals represent a new frontier in electrocatalyst design, and precise control of the host and minority metal distributions is crucial for elucidating structure-composition-property relationships and attaining superior catalytic performance.

Temperature-dependent ultrafast hot carrier dynamics in the dilute bismide alloy GaSb1−xBix (x ≾ 0.4%)

We report temperature-dependent hot carrier dynamics in liquid-phase epitaxy-grown GaSb1−xBix epilayers with dilute amounts of Bi (x ≾ 0.4%). Degenerate pump–probe (λ = 800 nm) transient reflectivity (PPTR) was used to investigate the carrier dynamics in the epilayers. The PPTR signal consists of two transient processes (fast and slow) at all temperatures for all epilayers. The fast, hot carrier relaxation time, which is attributed to the combined effect of intervalley scattering and thermalization of carriers below cryogenic temperatures (<100 K), is observed to increase with an increase in temperature (≈0.8–2 ps at 6.6 K and ≈4–5 ps at 300 K). However, at higher temperatures (>100 K), the interband CHSH-Auger recombination process affects the band-to-band recombination, leading to an increase in the slower decay time. The findings offer crucial insights for optimizing GaSbBi for hot carrier solar cell applications.

Dynamics of mono-size aerosolized liquid fuel detonations

Detonation-based propulsion has been an area of interest in the scientific community in terms of detonative combustion providing higher efficiency. However, most detonation research has focused on gaseous products though liquid fuel propellants are of interest for propulsion applications due to their high energy density. This research explores the use of an aerosolized liquid fuel as the combustion reactant. Jet-A is aerosolized into 5 μm droplets to fill the experimental facility, which has been pre-filled with oxidizer, and ignited. The reaction travels through a series of perforated plates that induce turbulence into the flow, and the ensuing detonation is imaged through the test section windows. Evidence of the Jet-A detonation is captured though high-speed shadowgraph, CH* chemiluminescence, and Mie scattering. Pressure measurements were also taken along the test section. This paper explores the dynamics of an aerosolized Jet-A driven detonation and discusses the droplet burning behavior. Several varying amounts of nitrogen dilution and both a stoichiometric and rich equivalence ratio was tested at each dilution level, giving insights into how these affect the detonation characteristics.

Advanced atmospheric pressure CVD of a-Si:H using pure and cyclooctane-diluted trisilane as precursors

Exploring the effects of cyclooctane dilution, deposition temperature, process duration, and precursor amount on a-Si:H film properties deposited from liquid trisilane in an atmospheric pressure CVD system.

Quantification of extracrystalline acid sites in MFI zeolites after post-synthetic passivation treatments using mesitylene benzylation kinetics

Mesitylene benzylation kinetics enable quantification of dilute amounts of external H+ sites in surface passivated MFI zeolites that are not assessable by conventional spectroscopic or titrimetric techniques.

Influence of steam dilution on ignition delay time of dimethyl ether/air mixtures at high pressure measured behind reflected shock waves

This work provides the first experimental data on ignition delay times of steam-diluted dimethyl ether/air mixtures at high pressure obtained behind reflected shock waves. Mixtures are prepared with 20 and 40vol% steam dilution and at equivalence ratios of 0.5, 1.0 and 2.0. The measurements comprise temperatures between 731 and 1314K and are recorded at nominal pressures of 15 and 35bar. The obtained experimental data is used for comparison and evaluation of predictions of common chemical-kinetic models. The effect of dilution on ignition delay time is furthermore studied numerically utilizing zero-dimensional reactor simulations with the chemical-kinetic model AramcoMech 3.0. Thermal and chemical effects of steam-dilution are analyzed in comparison to CO2 and N2 dilution. Steam dilution features a smaller heat capacity than CO2 at the investigated temperatures, which leads to a lower thermal effect and therefore shorter ignition delay time. The chemical effect of steam decreases ignition delay time at intermediate and high temperatures below the ignition delay time of a mixture with the same amount of N2 dilution. The chemical effect is mainly due to the high collision efficiency of H2O in the third body reactions H2O2 + H2O ↔ 2OH + H2O, H + O2 + H2O ↔ HO2 + H2O and CH3OCH3 + H2O ↔ CH3 + CH3O + H2O. At high temperatures the direct participation of H2O in reactions and its chemical conversion additionally exerts a further decreasing effect on ignition delay time.

Investigating the thermal and chemical kinetic effects of the internal residual on the cyclic dynamics at the dilute limits of a spark-ignition engine

The cyclic variability in the misfire and partial burn regimes of a dilute spark-ignition engine are primarily due to the feed-forward mechanism present in the residual gases. This study experimentally investigates the influence of the specific heat capacity/thermal effect and chemical kinetic effect of the internal residual on the heat release dynamics in the misfire and partial burn regimes of a dilute spark-ignition engine. Each effect is investigated by displacing excess air with bottled N2 and CO. Both short-term and long-term heat release dynamics are analyzed using association rules. Results show both an increased amount of dilution and higher specific heat capacity can result in similar dynamics. It was also found the misfire regime appears to be more sensitive to the chemical kinetic effect than the partial burn regime. Comparison of spark-to-CA05 and spark-to-CA50 between dilution methods was also conducted, where it was found the chemical kinetic effect did tend to reduce both spark-to-CA05 and spark-to-CA50. Overall, results from this study suggest different control strategies may be necessary to effectively mitigate the combustion instabilities when operating in each regime.

Soft pinning: Experimental validation of static correlations in supercooled molecular glass-forming liquids.

Enormous enhancement in the viscosity of a liquid near its glass transition is a hallmark of glass transition. Within a class of theoretical frameworks, it is connected to growing many-body static correlations near the transition, often called "amorphous ordering." At the same time, some theories do not invoke the existence of such a static length scale in the problem. Thus, proving the existence and possible estimation of the static length scales of amorphous order in different glass-forming liquids is very important to validate or falsify the predictions of these theories and unravel the true physics of glass formation. Experiments on molecular glass-forming liquids become pivotal in this scenario as the viscosity grows several folds (), and simulations or colloidal glass experiments fail to access these required long-time scales. Here we design an experiment to extract the static length scales in molecular liquids using dilute amounts of another large molecule as a pinning site. Results from dielectric relaxation experiments on supercooled Glycerol with different pinning concentrations of Sorbitol and Glucose, as well as the simulations on a few model glass-forming liquids with pinning sites, indicate the versatility of the proposed method, opening possible new avenues to study the physics of glass transition in other molecular liquids.

Use of Photo isomers to enhance the removal of lignin from woody biomass hydrolysate: UV irradiated photo isomerization of 4,4-diethoxy-azobenzene enhances precipitation of organosolv lignin from extraction solvents

Conversion of lignocellulose to bioproducts and biofuels is often initiated with a hydrolytic pretreatment process that helps to depolymerize the native polymers in biomass and produce a cellulose rich pulp stream. Extracting dissolved components (lignin) from this hydrolysate is an important step to derive value from the biomass components other than cellulose. In this investigation we propose a novel method to enable precipitation of desired solutes using photo-isomers in the extraction solvent. This photo-switchable solvent enables dissolution or precipitation of desired components using alternating UV or visible light to modify the solubility of the compounds of interest. It was found that among different combinations of three solvents and three photo-isomers, the combination of acetone with 4,4′-diethoxy azobenzene solution was most efficient at precipitating dissolved Organosolv lignin in response to UV light exposure. To our knowledge this is the first demonstration of this approach to separating lignin from organic solvents. This method is significant because it minimizes the high energy demands of traditional lignin extraction methods that involve distillation or large amounts of dilution using antisolvents.

Effects of dietary essential oil supplementation on growth performance, carcass yield, meat quality, and intestinal tight junctions of broilers with or without Eimeria challenge

The effects of dietary supplementation of essential oil on growth performance, carcass yield, meat quality, serum antioxidant capacity, and intestinal tight junctions of broilers with or without Eimeria challenge were investigated. A total of 576 one-day-old male broilers were randomly separated into 8 treatments (6 replication floor-pens per treatment, 12 broilers per pen) in a 4×2 factorial design. The 4 diets consisted of 1) a corn and soybean meal basal diet, 2) an anticoccidial diet (60 g nicarbazin and 60 g narasin per ton of feed), 3) an oregano oil diet (500 ppm oregano oil), and 4) a clove oil diet (500 ppm clove oil). On d 10, half chicks were challenged with 1×104 sporulated oocysts of E. tenella, E. acervulina, and E. maxima per chick, whereas the others were inoculated with an equal amount of dilution (0.5 mL). The Eimeria challenge induced a higher fecal oocyst output on d 18, a lower duodenum Occludin expression level on d 28, a lower serum catalase level, and a higher cook loss and protein loss in thigh muscle on d 42. The anticoccidial diet lowered fecal Eimeria output and increased d 1 to 42 BW gain as compared to the control diet. The clove oil treatment enhanced duodenum ZO-1 expression level in nonchallenged birds, increased BW gain from d 1 to 14 and breast yield on d 42. The oregano oil treatment enhanced ZO-1 expression of challenged birds, reduced feed intake from 15 to 28 d, and helped broilers gain more tender meat. For those Eimeria-challenged broilers, both clove and oregano oil treatments recovered drip loss in breast muscle. Our results suggested that Eimeria challenge in broiler early age could interrupt later serum antioxidant capacity and damage meat quality. The dietary supplementation of clove or oregano essential oils could improve broiler growth performance and partially relieve the coccidial damage in gut integrity and meat quality.

Intriguing physicochemical properties and impact of co-dopants on N-doped graphene oxide based ZnS nanowires for photocatalytic application

Superparamagnetic N-doped graphene oxide (GO)- with ZnS nanowires was synthesized by a one-step hydrothermal method by doping dilute amounts of Ga, Cr, In, and Al ions for water treatment and biomedical applications. In these experiments, to enhance their properties, 2% of Ga3+, In3+, and or Al3+ were codoped along with 2% Cr ions in these ZnS nanowires. The nanocomposite with the composition, In0.02Cr0.02Zn0.96S, has better photocatalytic efficiency than other co-doped nanocomposites. The In (metalloids) and Cr (transition metal ion) are the best combinations to increase the magnetic properties which are beneficial for photocatalytic activity. Synthesized nanocomposite materials were characterized by several techniques such as X-ray diffraction, Field emission-scanning electron microscope (FESEM) with EDAX, vibrating sample magnetometer (VSM), UV–Vis, X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy. The correlation of intriguing magnetic properties with their photocatalytic properties is also discussed. XPS was employed for the detection of surface defects, phase transformation, and the nature of chemical components present in the nanocomposites. The Frankel and substitutional defects have a direct impact on photocatalytic activity that was determined from the fluorescence (FL) spectroscopy. FL and XPS reveal that the Cr and In codoped composite has a higher percentage of defects hence its photocatalytic efficiency reaches 94.21%.

International Collaborative Cluster-Based Carbon Sequestration Plan

The status quo climate change forecast was analyzed using the ENROADS software and indicates that the net GHG emissions could reach about 90 gigatons of CO2 equivalent by 2100, and global temperatures could rise by 3.6°C. This projection will likely be worse even with moderate estimates. The factors used in the reported status quo forecasts are optimistic. From energy mix to population growth and the assumption that gas use could increase while oil declines, this scenario is limited by available gas reservoirs. There needs to be a more aggressive application of CCS to reach Net-Zero by 2050. Carbon Capture and Storage (CCS) has been identified as the leading technology that could help reduce the amount of CO2 emitted into the atmosphere. At the same time, the search for non-fossil fuel energy sources continues. The amount of CO2 dilution in the air stream complicates the economics of direct air capture. This research proposes two international collaborative clusters for India. Due to India's growth and use of fossil energy sources, this is necessary to manage CO2 emissions from coal-fired plants. The results show that cluster-based CCS facilities possess great potential for the world to develop faster carbon capture and sequestration technology and deploy it faster. These cluster CCS systems will create economies of scale and integration necessary to make the CCS technology succeed to help reduce India's and global CO2 emissions from fossil-fuel-powered electricity generation. If CCS is deployed at the proposed scale, it will reduce atmospheric CO2 significantly, which would capture more than 250 times more than today's effort.

Defect Reconfiguration in Hole-Doped PbSe via Minute Te Doping for Significantly Enhanced Thermoelectric Performance

Rich defects near the percolation threshold of dilute solid solutions are of fundamental interest to thermoelectric research. Sn-substituted Pb0.98Na0.02Se (1 mol %) is a typical example that demonstrates how various defects induce intriguing transport phenomena. Unfortunately, the presence of Pb vacancies severely degrades the carrier mobility of samples, and the thermoelectric figure of merit ZT is only marginally improved. In this study, we show that Pb vacancies are effectively inhibited by a facile defect reconfiguration strategy. This is achieved by doping a dilute amount of Te at Se sites of Pb0.97Sn0.01Na0.02Se, where the interstitial Sn ions are pulled back to Pb sites as revealed by the X-ray photoelectron spectroscopy analysis and the positron annihilation test. Consequently, Pb vacancies get occupied, and the room temperature carrier mobility is remarkably recovered from 2.8 to 70 cm2 V–1 s–1 upon 3 mol % Te doping. Moreover, Te doping reinforces phonon scattering by strain and mass field fluctuations. The lattice thermal conductivity at 300 K goes down to ∼1.7 W m–1 K–1 for Pb0.97Sn0.01Na0.02Se0.94Te0.06, which is ∼32% lower than that of the Pb0.97Sn0.01Na0.02Se control sample. Altogether, the average ZT value of Pb0.97Sn0.01Na0.02Se between 300 and 773 K is doubled upon 6 mol % Te doping.

Application of Environmental Isotopes and Hydrochemistry to Identify the Groundwater Recharge in Wadi Qanunah Basin, Saudi Arabia

The current study focuses on the Wadi Qanunah basin, which is considered one of Makkah Al-Mukarramah’s most important watersheds. It is located in the southwestern part of the Al Qunfudhah governorate. The identification and characterization of the recharging sources for the quaternary aquifer is one of the most important goals of this study. In this context, different methods will be applied for the identification of the different factors impacting groundwater. Such methods will be based on the integration of geographic information system (GIS) and modern hydrochemical methods ranging from graphical plots, bivariate and multivariate analysis to geochemical modeling. The salinity of the groundwater studied varied from fresh to brackish, according to the seasonal influx of dilute runoff and the dissolution of the weathered rocks, as well as the cementing materials within the aquifers’ matrix. Ionic ratios indicated that ion exchange, silicate weathering and evaporation played a significant role in the enrichment of the groundwater with major constituents including calcium, sodium, magnesium, sulphate and chloride. Furthermore, four factors accounted for 73.92% of the total variance, calculated using SPSS’s statistical program. These factors accounted for leaching and dissolution, silicate and carbonate weathering, anthropogenic effects and evaporation. The δ18O vs. δD, TDS vs. δ18O and δ18O vs. d-excess relationships revealed that local rainfall is the main recharging source for groundwater; some samples were affected by evaporated rainfall, while others with lower salinity (<1000 mg/L) were diluted through seepage from the underlying fractured basement aquifer. Netpath geochemical modeling was applied to calculate the amount of evaporation or dilution which had affected an initial body of water as it moves from the upstream to downstream. The output of this program is consistent with what has been proved by stable isotopes, where the groundwater extracted from the final water is a mixture of an enriched recent precipitation with depleted older water. This study is an attempt to shed light on the assessment of groundwater and the extent at which it is affected by various factors in order to benefit from it in a way that ensures its sustainability.