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Noting that the conventional collision-dominated electron transport perspective is only relevant when the length scale over which the transit occurs is greater than the electron's mean free path, one can conceptually partition the electron transport "space" into collision-dominated and ballistic electron transport regimes. As the boundaries between these regimes are quite porous, in this analysis, we devise a means of quantitatively examining the transition between electron transport regimes as the length scale is reduced on a continuum basis. Our approach introduces a collision-dominated fractional scattering parameter, this parameter quantifying the fraction of the total scattering rate that arises purely from bulk scattering processes, contact scattering also contributing to the total scattering rate. We pursue this analysis for two conventional semiconductors of interest, silicon and gallium arsenide. A determination of the dependence of the results on both the length scale and the crystal temperature is pursued. Finally, for the specific case of room temperature, a comparison with the results of experiment is performed. [ABSTRACT FROM AUTHOR]

Within the framework of an electron transport regime classification scheme, we aim to explore the boundaries that occur between the ballistic, collision-dominated, space-charge injection, and non-space-charge injection electron transport regimes that are experienced by an electron within a semiconducting device, mapping out where these different electron transport regimes are. We do this by determining the electron's mean free path and the relevant screening length. In order to make this analysis concrete, we perform this analysis for four representative semiconductor material systems, including silicon, gallium arsenide, the 4H-phase of silicon carbide, and the wurtzite phase of gallium nitride. The entire analysis is performed using a two-dimensional approach, this being representative of the electron transport that is experienced by an electron in the vicinity of a two-dimensional electron gas. Finally, following an evaluation of the dependence of the ballistic mobility on the device length scale for all four materials, an evaluation of the effective mobility as a function of the channel-length scale is pursued, a Matthiessen-rule based approach being employed for the purposes of this analysis. [ABSTRACT FROM AUTHOR]

This research marks an advancement in the field of environmental remediation by introducing a novel sorbent material tailored for the efficient removal of crude oil from industrial wastewater. By focusing on the modification of cotton fibers with charcoal and bentonite, the study addresses the pressing need for sustainable solutions to oil contamination in aquatic environments. Through a comprehensive array of characterization techniques including FT‐IR, TGA, XRD, SEM, EDS, and BET analysis, the structural and surface properties of the modified materials were thoroughly examined, providing insights into their suitability for practical applications. Sorption studies conducted to determine sorption capacity, optimize sorbent amount, and evaluate the effect of contact time on removal efficiency yielded favorable results, highlighting the potential of the developed sorbents to effectively treat crude oil in aqueous solutions. Additionally, the investigation of sorption kinetics using pseudo‐first‐order, pseudo‐second‐order, and intra‐particle diffusion models elucidated the underlying adsorption mechanisms governing the interaction between the sorbent and crude oil molecules. These findings not only contribute to the scientific understanding of sorption processes but also offer practical guidance for the development of optimized sorbent materials and remediation strategies. Overall, this study represents a significant step toward the development of cost‐effective and environmentally friendly methods for oil spill cleanup and industrial wastewater treatment, with implications for sustainable water management practices worldwide. Continued research efforts in this direction hold promise for further advancements in the field, potentially leading to more efficient and scalable solutions for addressing the global challenge of oil contamination in water environments. [ABSTRACT FROM AUTHOR]

Emerging consequences due to the expansion of urbanization, unfair distribution of wealth, facilities and services on the one hand, and the poor state of the economy, unemployment and the consequent reduction in government revenues, which leads to a reduction in the support of organizations for vulnerable people, on the other hand, have affected the social hope of citizens.using sociological theories, we tried to find the factors affecting social hope among Tehrani citizens, and five variables were obtained from theories to explain the causes of social hope, including life satisfaction, social security, feeling of powerlessness, social trust, and social inequality. The research method is a quantitative-survey type and the sample showed that all five independent variables had an effect on the social hope of Tehrani citizens, which according to the correlation coefficient, With the increase of social trust, social security and life satisfaction, the level of social hope also increases, but on the other hand, with the increase of the feeling of powerlessness and social inequality, the level of social hope will decrease. In addition, the results of direct, indirect and total standard coefficients in structural equations showed that the variables of life satisfaction and social inequality, in addition to the direct and significant effect on the variable of social hope, have an indirect and significant effect through the mediation of the three variables of social trust, social security And they also feel powerless. [ABSTRACT FROM AUTHOR]

Because of their strong chemical stability and composition adjustability, lanthanide perovskite oxides have attracted much attention. La2CoMnO6 double perovskite oxide catalysts and derived materials La2-xCoMnO6 with x = 0.02, 0.05, 0.10, and 0.15 have been synthesized using the facile sol-gel method, and their catalytic deep oxidation performance was probed in the propane combustion reaction. Compared with stoichiometric double perovskite, nonstoichiometric samples exhibited different activity and stability. Among the investigated samples, the La2-0.05CoMnO6‌ catalyst exhibited the best performance for propane catalytic combustion. Propane could reach 90% conversion at 423 °C on the best catalyst. Besides, the stability of this catalyst was better than the stoichiometric double perovskite. The elaborated samples were characterized by a variety of techniques, such as XPS, XRD, ICP, H2-TPR, O2-TPD, and FTIR. Better reducibility and boosted oxygen vacancy content were responsible for improving propane degradation on the catalyst, which was correlated with the induction of lanthanum ion deficiency in La2CoMnO6 samples. Highlights: Certain amount of La-deficiency is conducive to the best performance of La2CoMnO6 catalysts. Nonstoichiometry in double perovskite oxides led to augmented durability in deep propane oxidation. Proper tuning of oxygen species and the reducibility of double perovskite led to boosted combustion activity. [ABSTRACT FROM AUTHOR]

One of the main problems during oil well completion and cementing operation is fluid migration through cement bulk or behind the cemented casing. Slurry composition and characteristic have been focused and improved in last decades to mitigate gas migration and, recently, aspects such as using nanotechnology have been investigated to amend the conditions. In this research, two moderate base slurries with 95 and 120 Pound per Cubic Feet (PCF) densities containing different percentages of nanosilica have been examined using a perfect test package. The results of Fluid Migration Analyzer (FMA) demonstrated that using correct percentage of nanosilica particles modified rheological behavior of the slurries and decreased fluid migration volume. Moreover, adding nanoparticles did not have any negative effects on any conventional parameters. However, static gel strength analyzer showed significant transient time reduction which is an important key in cement setting profile. Triaxial test results together with Mohr circles analyzing presented considerable progress in cement stability and compressive strength.

Absorption of carbon dioxide (CO2) from flue gases is very important to various industries and chemical absorption by diethanolamine (DEA) can be used for this purpose. This work dealt with the effect of operating parameters on the CO2 output concentration and the absorption rate of CO2 in aqueous DEA solution. CO2 was absorbed in a falling film reactor at standard pressure and temperature. The reactor length and diameter were 1m and 0.0254m, respectively. The values of the CO2 output concentration vary between 23 to 7393 ppm and the absorption rate of CO2 in aqueous DEA varies between 2.68E-08 to 2.40E-07 kg/s. The results showed that the absorption rate of CO2 in the aqueous DEA solution increased with an increase in gas flowrate, the CO2 concentration in gaseous mixture and DEA percent. In addition, the results were statistically examined by Design-Expert software, using response surface experiment design and a historical method. Two mathematical relations were proposed to estimate the output concentration of CO2 and the absorption rate of CO2 in the aqueous DEA solution with good accuracy for falling film reactor (ReG ∈ [1; 6] and ReL ∈ [4; 40] at 298 K). [ABSTRACT FROM AUTHOR]

Pressure gradient of a two phase mixture in a horizontal pipe were experimentally investigated for water/super viscose oil mixtures. The mixture contained oil having a viscosity of 67 cp and density of 0.872 g/cm3, and pure water, flowing through an acrylic pipe having a length and diameter of 6 m and 20 mm, respectively. A high speed digital camera has been used to record visual information. Superficial velocities of water and oil were in the range between 0.18-1.2 m/s and 0.18-0.95 m/s, respectively. The experimental pressure gradient has been compared to the Al-Wahaibi correlation and two-fluid model. The absolute average error for the "two-fluid model" and Al-Wahaibi correlation have been calculated for 30% and 12%, respectively. In this investigation, a new modified correlation is developed on the basis of the Al-Wahaibi correlation, that predicts the values of pressure gradient with an absolute average error of about 9%. The pressure gradient correlation was validated extensively against 11 independent data sources. To our knowledge, this is the best pressure gradient furmola that is published for oil--water flow which includes wide range of operational conditions including fluid properties, pipe diameters and pipe materials. One of the advantages of the new proposed formula is that it also performs well for super viscosity oils. [ABSTRACT FROM AUTHOR]

Water can contain microorganisms and cause deposition and corrosion in cooling tower systems. Therefore, the water treatment of cooling towers is essential. Various biocides are used to remove bacteria and disinfect the water of cooling towers, and the most commonly used are sodium hypochlorite and chlorine compounds. This work examined two chlorinated water, namely hypochlorous acid and sodium hypochlorite, in two pilot and industrial cooling towers. The results of the experiments on the pilot tower showed that the performance of hypochlorous acid in the disinfection and removal of bacteria and microorganisms was excellent. The total bacterial count decreased from 10000 to less than 800 (cfu/mL) compared to sodium hypochlorite. The experiments were performed on the industrial cooling tower of an acetic acid unit for six months, in which pH, free chlorine, total bacterial count (TBC), and sulfate-reducing bacteria (SRB) were measured. The very high disinfection power of hypochlorous acid compared to sodium hypochlorite and its relatively lower pH level led to a significant reduction in the use of chemicals in the cooling tower. The experiments and TBC and SRB tests showed outstanding performance in using hypochlorous acid. [ABSTRACT FROM AUTHOR]

Hydrostatic pressure less than pore pressure and the existence of a path to gas migration are two major factors that must be stopped simultaneously to prevent migration. Understanding the mechanisms of cement hydration in early times is necessary to investigate these factors. Cement hydration can lead to swelling and shrinkage at the same time. At the beginning of cementation chemical shrinkage occurs, followed by swelling and autogenously shrinkage, and the degree of hydration, the water-cement ratio and the fineness of cement. The most important factors that make the annulus pressure less than the pore pressure are: cement placement, Cement hydration in liquid state, and Cement hydration in solid-liquid state. [ABSTRACT FROM AUTHOR]