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The purpose of this research is to investigate speech sound disorders in Urdu-English bilingual children, with a focus on the generalization of phonological knowledge across languages during treatment. Carlos D. Nye's (2019) study on young non-native bilinguals found that there was concurrent growth across phonological systems while treatment was administered in the native language (Spanish) of the bilinguals. This study aims to answer the question of whether it is possible to facilitate cross-linguistic generalization for "targets with shared phonetic features" in young Urdu-English bilinguals who are struggling with speech sound disorders. It is expected that shared phonetic features in Urdu (L1) would generalize into English (L2), despite differences in shared and unshared sounds between these languages and others in which the researcher is fluent as a native speaker. The findings of this study can be used to inform clinical procedures and approaches for bilingual clinicians and speech-language pathologists and support the interdependent structure of the phonological organization in young bilinguals. It is worth noting that there is a shortage of bilingual clinicians and SLPs, with only around 8% of current SLPs speaking more than one language and an increasing number of bilinguals suffering from communication disorders. The results of this study have the potential to provide much-needed assistance to bilinguals who have been struggling with these issues.

The concern to reduce global carbon emissions has significantly improved the development of efficient solid sorbents such as activated carbon (AC). In this study, AC is developed from date stones which is one of the abundantly found agricultural waste material in gulf region. The AC was completely characterized in terms of pore volume, surface area, stability test, volatile carbon and fixed carbon contents. Impregnation of AC was performed by three different alkanolamines, namely Diethylene triamine (DETA), Pentaethylene hexamine (PEHA) and Di-ethanol amine (DEA). The alkanolamine impregnated sorbents were utilized for CO2adsorption at temperatures of 25, 30, 40, 50, 60, 70 and 100 °C and carbon dioxide (CO2) concentrations of 10, 30, 50, 70 and 92% in helium. The adsorption phenomenon was evaluated by Langmuir isotherms for all the studied adsorbents. The AC developed from date stones provided high adsorption loading capacity of CO2 i.e., 89.79 mg/g of AC at 25 °C. Thermodynamic parameters showed that the adsorption was endothermic and spontaneous in nature. Moreover, desorption profiles reveal that DETA-AC samples provided most favorable characteristics with respect to the value of desorption constant.

In this study, the densification of three agriculture waste biomasses (corn cobs, cotton stalks, and sunflower) is investigated using the torrefaction technique. The samples were pyrolyzed under mild temperature conditions (200–320 °C) and at different residence times (10 min–60 min). The thermal properties of the obtained bio-char samples were analyzed via thermo-gravimetric analysis (TGA). Compositional analysis of the torrefied samples was also carried out to determine the presence of hemicellulose, cellulose, and lignin contents. According to the results of this study, optimum temperature conditions were found to be 260 °C–300 °C along with a residence time of 20 min–30 min. Based on the composition analysis, it was found that biochar contains more lignin and celluloses and lower hemicellulose contents than do the original samples. The removal of volatile hemicelluloses broke the interlocking of biomass building blocks, rendering biochar brittle, grindable, and less reactive. The results of this study would be helpful in bettering our understanding of the conversion of agricultural waste residues into valuable, solid biofuels for use in energy recovery schemes. The optimum temperature condition, residence time, and GCV for torrefied corn cobs were found to be 290 °C, 20 min, and 5444 kcal/kg, respectively. The optimum temperature condition, residence time, and GCV for torrefied cotton balls were found to be 270 °C, 30 min, and 4481 Kcal/kg, respectively. In the case of sunflower samples, the mass yield of the torrefied sample decreased from 85% to 71% by increasing the residence time from 10 min to 60 min, respectively.

Well-designed 1D/2D composite, consisting of carbon nanotubes modified protonated carbon nitrides (CNTs/pCN) embedded with Cu-NPs were synthesized by a facile sonicated assisted chemical method. The performance of catalysts towards dynamic CO2 reduction to selective fuels was conducted under UV/visible light irradiations in a continuous flow photoreactor. Photo-activity of g-C3N4 for CO production was increased by 2.38 folds after surface charge modification due to faster charge carrier separation. Loading 3 wt% Cu and 0.5 wt% CNTs into pCN gave highest activity for the production of CO, CH4 and CH3OH under visible light. The highest CO yield as the main product over Cu-CNTs/pCN composite was 560 μmole g-cat−1 h−1, a 1.21, 1.36, 3.78 and 9.03 folds higher than using Cu/pCN, CNTs/pCN, pCN and g-C3N4 samples, respectively. This significantly enhanced photo-activity can be attributed to visible light absorption and multi-stage charges separation in the presence of Cu/CNTs. More interestingly, CO obtained under visible light was 4 times higher than using UV-light, while performance for CH4 production was 14 folds higher with visible light than using UV-light under the same operating conditions. Among the different catalyst loadings, 150 mg gave highest productivity, evidently due to limitations in exposed catalyst active surface area. Additionally, Cu-CNTs/pCN photocatalyst prevailed excellent stability in cyclic runs for continuous CO2 reduction. The findings of this work would be attractive for the development of CO2 conversion systems with renewable fuels production under solar energy.

Conversion of carbon dioxide (CO2) and methane (CH4) to fuels using photo-technology is a cleaner pathway compared to thermal reforming, since its uses only light irradiations, while producing valuable chemicals. In this study, structured nickel (Ni) and montmorillonite (MMT) supported TiO2 composite, synthesized by a sol-gel method, was tested for photocatalytic reduction of CO2 using fixed-bed and monolith photoreactors. The performance of structured nanocatalyst was evaluated using CO2-H2 system via photocatalytic reverse water gas shift (RWGS) reaction and CO2-CH4 system via photocatalytic dry reforming of methane (DRM). Using photocatalytic RWGS, CO was detected as the main products, while the performance of Ni-MMT/TiO2 composite was expressively higher than using MMT/TiO2 and TiO2 catalysts. This was obviously due to larger surface area by MMT dispersion and hindered charges recombination rate by Ni. Similarly, using DRM, H2 and CO were the main products, while their selectivity was greatly dependent on the initial CH4/CO2 molar feed ratios. At a lower CH4/CO2 ratio, more CO was produced, while a higher feed ratio promoted H2 production. This shows, composite catalyst was more favorable for CO2 adsorption, while CH4 was competitively adsorbed during photo-catalysis process. Comparatively, Ni-MMT/TiO2 catalyst reveals higher photo-activity and selectivity in a monolith photoreactor than using fixed-bed reactor under the same operating conditions. This enhanced photoactivity was due to higher photonic flux with enlarged active surface area due to monolithic support and efficient sorption process. The stability of Ni/TiO2 dispersed MMT for CO and H2 production via DRM process sustained in cyclic runs using monolithic support. Hence, using Ni/MMT modified TiO2 catalyst in a monolith photoreactor, CO2 and CH4 can efficiently be converted to renewable fuels under light irradiations and would be a great benefit to the environment.

Chromium(III)-based metal-organic framework was prepared by using a tritopic bridging 1,3,5-Tris(4-carboxyphenyl) benzene ligand as a linker and chromium as metal that forms a secondary building unit, by solvothermal method. Continuous weight loss of Cr-MOF sample in the entire temperature range was related to loss of desorption of adsorbed gases from pores and cavities, removal of guest molecules such as N,N-dimethyl formamide, and framework disintegration. Specific surface area was found to be 420 m2/g and significant steep raise in the isotherm at partial pressure >0.2 indicates microporous character of the sample. The CO2 adsorption capacity of Cr-MOF sample measured at 298 K and partial pressure of 0.9 atm was found to be 3.5 wt.%. Temperature elevation from 298 to 343 K decreases adsorption capacity according to the Le-Chatelier's Principle. The CO2 adsorption increases linearly as the pressure increases from 0 to 0.9 atm is due to relatively weak adsorption sites and homogeneity.

Photocatalytic CO2 methanation using H2O vapors and/or H2 reductants over nickel (Ni) and indium (In) promoted TiO2 nanocatalysts has been investigated. The physical–chemical characteristics of the catalysts, prepared through a sol–gel method with different Ni and In doping levels, were characterized by XRD, FESEM, TEM, FTIR, XPS, N2 adsorption–desorption, UV–vis diffuse reflectance, Raman and photoluminescence spectroscopy. The controlled crystallites growth with increased specific surface area and reduced pore diameter were observed by NiO and In2O3 loading into TiO2. In and Ni metals present in TiO2, oxidized as In2O3 and NiO, promoted efficient separation of photo-generated charges (e−/h+). Using H2O as a reductant, CO2 was efficiently converted to CH4 over co-loaded TiO2 catalysts and the optimal loading amount was determined to be 1 wt.% NiO and 3 wt.% In2O3, giving a CH4 production rate of 240 μmole g−1 h−1 at selectivity 80%. This photoactivity of NiO and In2O3 loaded TiO2 catalyst for CO2 methanation was 2 fold more than the yield rate over In2O3/TiO2 and 6.5 times more the amount produced over the pure TiO2. The enhancement was attributed to charge transfer property and efficient suppressed recombination rate by Ni and In metals. In the presence of H2 reductant, both CO and CH4 were produced in significant amount and the maximum yield rates detected were 243 and 208 μmole g−1 h−1, respectively. Therefore, H2O reductant found to be more efficient for CH4 production, yet the CO2 reduction process was more favorable with H2, where the total amounts of products were considerably enhanced. In addition, a photocatalytic reaction mechanism is proposed to understand experimental results over the NiO and In2O3 loaded TiO2 catalysts.

Dwindling fossil fuel reserves require the efficient usage until sustainable alternatives fully replace them. Overall efficiency and output is used to rank the stationary combined cycle gas turbines. Efficient gas turbines require high combustion chamber temperature resulting in NO x generation. Furthermore, low-quality fuel increases the fraction of acidic gases in the exhaust. In this work a novel modification in combined cycle gas turbine cycle is presented, increasing the overall efficiency and decreasing acidic gases production along their capture, before rejection to stack. The modification is implemented on simulated General Electric 9HA.02 turbine using ASPEN HYSYS ® v8.6. Applying efficiency and exhaust temperature limit (constraints), bounds the discrepancies in simulated and real gas turbine parameters. A rise of 0.77% in efficiency and a considerable decrease in acidic gases (exhaust) is observed. Different gas turbine operational features pertinent to overall efficiency have been studied. An unprecedented control technique is presented as an addition to the proposed modification to achieve higher efficiencies under part load conditions.

Magnesium hydride (MgH 2 )–carbon nanotubes (CNT) composite has been prepared by high-energy ball milling method and their experimental and kinetic hydrogen adsorption studies was assessed. Hydrogen adsorption studies were performed by Sievert’s volumetric apparatus and kinetic evaluation was conducted by surface chemistry and Langmuir–Hinshelwood–Hougen–Watson (LHHW) type mode. Powder X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were performed. Hydrogen adsorption capacity of commercial MgH 2 , milled MgH 2 , and MgH 2 /CNT composite are found to be 0.04, 0.057, and 0.059 g (H 2 )/g (MgH 2 ) at 673 K and hydrogen pressure of 4.6 MPa. Addition of 5 wt% of CNTs to MgH 2 proved to be very critical to enhance hydrogen adsorption as well as to improve its kinetics. It was observed that hydrogen adsorption is not in quasi-state equilibrium and is modeled using kinetic rate laws.

The impurities CO2 and H2S in natural gas (NG) are recognized as major contaminants that exacerbate economic, operational, and environmental losses. Generally, these undesirable impurities are removed using well-established amine-based absorption methods. However, typical methods in this category are cost-intensive, primarily due to their high operating and maintenance costs. The ionic liquids (ILs) are emerging as alternative solvents owing to their lower regeneration costs and non-flammable nature. However, ILs could not attain a significant attention from practitioners due to the lack of effective communication between industry and academia. In this context, a comprehensive review and analysis of specific ILs that can simultaneously remove H2S and CO2 is proposed. This article highlights the major challenges and issues associated with various acid gases removal approaches, particularly IL-based absorption techniques. Recent developments toward solving the major issues associated with absorption using ILs are assessed to highlight areas for further improvement. The acid gas solubility data for ILs are analyzed to evaluate the feasibility and associated major constraints for large-scale process designs using commercial process simulators. Furthermore, the fundamentals for the process systems engineering-based investigations using ILs are also highlighted and evaluated. This study concludes that ILs have the potential to completely replace conventional solvents, have synergistic effects in terms of energy savings, and provide feasible solutions to maintenance-related issues.

Template-free fabrication of graphitic carbon nitride nanotubes modified with lanthanum (La/g-CNT) for dynamic photo-catalytic CO2 reduction with CH4 has been investigated. Successful fabrication of g-C3N4 nanosheets and nanotubes were obtained with enhanced photo-activity under visible-light. Using 5 wt% La/g-CNT, CO yield of 491 µmole g-cat−1 h−1 was obtained which is 3.6 and 5.9 folds higher than g-CNS and g-CN samples. Similarly, production of H2 was highest over La/g-CNT which was 2.95 folds more than g-CNT and 5.1 times higher than using g-CN. Although, pristine g-CN has more basic sites and larger BET surface area but enhanced photo-activity over La/g-CNT can be attributed to efficient transfer of electrons over 1D structure and separation of charge carriers by La. More interestingly, effect of CH4/CO2 feed ratios was obvious, whereas, highest CO was produced at CH4/CO2 ratio of 1.0 but H2 was maximum with ratio of 2.0. Among the different reaction systems, highest CO was obtained using DRM, while CO2 reduction by H2/H2O promoted both CO and CH4 production. This was obviously due to basic characteristics, sorption competition over the catalyst surface and favorable reverse water gas shift (RWSG) reaction. The stability test further confirmed the suitability of this material which prevailed until three cycles without obvious deactivation. This work will open new opportunities to develop structured nanocalaysts for solar energy based reutilization of CO2 and CH4 for the production of renewable fuels.