Reduction System Research Articles

5-Hydroxymethylfurfural and its Downstream Chemicals: A Review of Catalytic Routes.

Biomass assumes an increasingly vital role in the realm of renewable energy and sustainable development due to its abundant availability, renewability, and minimal environmental impact. Within this context, 5-hydroxymethylfurfural (HMF), derived from sugar dehydration, stands out as a critical bio-derived product. It serves as a pivotal multifunctional platform compound, integral in synthesizing various vital chemicals, including furan-based polymers, fine chemicals, and biofuels. The high reactivity of HMF, attributed to its highly active aldehyde, hydroxyl, and furan ring, underscores the challenge of selectively regulating its conversion to obtain the desired products. This review highlights the research progress on efficient catalytic systems for HMF synthesis, oxidation, reduction, and etherification. Additionally, it outlines the techno-economic analysis (TEA) and prospective research directions for the production of furan-based chemicals. Despite significant progress in catalysis research, and certain process routes demonstrating substantial economics, with key indicators surpassing petroleum-based products, a gap persists between fundamental research and large-scale industrialization. This is due to the lack of comprehensive engineering research on bio-based chemicals, making the commercialization process a distant goal. These findings provide valuable insights for further development of this field.

Photocatalytic Conversion of CO2 to Formate/CO by an (η6-para-Cymene)Ru(II) Half-Metallocene Catalyst: Influence of Additives and TiO2 Immobilization on the Catalytic Mechanism and Product Selectivity.

The catalytic efficacy of the monobipyridyl (η6-para-Cymene)Ru(II) half-metallocene, [(p-Cym)Ru(bpy)Cl]+ was evaluated in both mixed homogeneous (dye + catalyst) and heterogeneous hybrid systems (dye/TiO2/Catalyst) for photochemical CO2 reduction. A series of homogeneous photolysis experiments revealed that the (p-Cym)Ru(II) catalyst engages in two competitive routes for CO2 reduction (CO2 to formate conversion via RuII-hydride vs CO2 to CO conversion through a RuII-COOH intermediate). The conversion activity and product selectivity were notably impacted by the pKa value and the concentration of the proton source added. When a more acidic TEOA additive was introduced, the half-metallocene Ru(II) catalyst leaned toward producing formate through the RuII-H mechanism, with a formate selectivity of 86%. On the other hand, in homogeneous catalysis with TFE additive, the CO2-to-formate conversion through RuII-H was less effective, yielding a more efficient CO2-to-CO conversion with a selectivity of >80% (TONformate of 140 and TONCO of 626 over 48 h). The preference between the two pathways was elucidated through an electrochemical mechanistic study, monitoring the fate of the metal-hydride intermediate. Compared to the homogeneous system, the TiO2-heterogenized (p-Cym)Ru(II) catalyst demonstrated enhanced and enduring performance, attaining TONs of 1000 for CO2-to-CO and 665 for CO2-to-formate.

Efficacy of virtual surgical planning and a three-dimensional-printed, patient-specific reduction system to facilitate alignment of diaphyseal tibial fractures stabilized by minimally invasive plate osteosynthesis in dogs: A prospective clinical study.

To evaluate the efficacy of a three-dimensional (3D)-printed, patient-specific reduction system for aligning diaphyseal tibial fractures stabilized using minimally invasive plate osteosynthesis (MIPO). Prospective clinical trial. Fifteen client owned dogs. Virtual 3D models of both pelvic limbs were created. Pin guides were designed to conform to the proximal and distal tibia. A reduction bridge was designed to align the pin guides based on the guides' spatial location. Guides were 3D printed, sterilized, and applied, in conjunction with transient application of a circular fixator, to facilitate indirect fracture realignment before plate application. Alignment of the stabilized tibiae was assessed using postoperative computed tomography scans. Mean duration required for virtual planning was 2.5 h and a mean of 50.7 h elapsed between presentation and surgery. Guide placement was accurate with minor median discrepancies in translation and frontal, sagittal, and axial plane positioning of 2.9 mm, 3.6°, 2.7°, and 6.8°, respectively. Application of the reduction system restored mean tibial length and frontal, sagittal, and axial alignment within 1.7 mm, 1.9°, 1.7°, and 4.5°, respectively, of the contralateral tibia. Design and fabrication of a 3D-printed, patient-specific fracture reduction system is feasible in a relevant clinical timeline. Intraoperative pin-guide placement was reasonably accurate with minor discrepancies compared to the virtual plan. Custom 3D-printed reduction system application facilitated near-anatomic or acceptable fracture reduction in all dogs. Virtual planning and fabrication of a 3D-printing patient-specific fracture reduction system is practical and facilitated acceptable, if not near-anatomic, fracture alignment during MIPO.

Charge Transport Approaches in Photocatalytic Supramolecular Systems Composing of Semiconductor and Molecular Metal Complex for CO2 Reduction.

The design of photocatalytic supramolecular systems composing of semiconductors and molecular metal complexes for CO2 reduction has attracted increasing attention. The supramolecular system combines the structural merits of semiconductors and metal complexes, where the semiconductor harvests light and undertakes the oxidative site, while the metal complex provides activity for CO2 reduction. The intermolecular charge transfer plays crucial role in ensuring photocatalytic performance. Here, we review the progress of photocatalytic supramolecular systems in reduction of CO2 and highlight the interfacial charge transfer pathways, as well as their state-of-the-art characterization methods. The remaining challenges and prospects for further design of supramolecular photocatalysts are also presented.

Design and Implementation of English to Yorùbá Verb Phrase Machine Translation System

The Yorùbá ethnic group has diverse language speakers across the world, and translating the language to other widely spoken languages must be emphasized. This study aims to develop an English to Yorùbá machine translation system which can translate the English verb phrase text to its Yorùbá equivalent. Words from both languages (Source Language and Target Language) were collected for the verb phrase group in the home domain. Lexical translation was done by assigning values of the matching word in the dictionary. The syntax of the two languages was realized using Context Free Grammar, the rewrite rules were validated with finite state automata. Human evaluation method was used and expert opinion scored. The evaluation shows the system performed better than that of sampled Google translation with over 70% of the responses matching that of the system’s output.

Long-term stress characteristics of a box culvert with a load reduction system using geogrids and EPS under high fill

Laying geogrids and compressible materials, such as expandable polystyrene (EPS), on the tops of culverts under high fill can improve the stability of the fill and reduce the earth pressure on the tops of culverts. The creep of geogrids and compressible materials under high fill affects the stress state of culvert–soil systems. However, the long-term behaviour of culverts with geogrids and EPS is not clear. This paper investigates the long-term behaviour of culvert–soil interactions under high fill, specifically focusing on the creep effects of geogrids and EPS boards. A novel mechanical model for determining the long-term stress characteristics of culverts is proposed based on limit equilibrium theory. A comparison with finite difference simulation results was conducted to validate the proposed model. The findings reveal that the vertical earth pressure on the culvert top gradually transfers to the culvert side, exhibiting a nonlinear decrease over time. Moreover, the horizontal earth pressure on the culvert sidewall exhibits nonlinear growth with time, decreasing incrementally with depth. The maximum horizontal earth pressure on the culvert sidewall increases by 12.5% postconstruction, emphasizing the importance of accounting for the creep effects of geogrids and EPS boards in engineering design to prevent structural issues.

Economic and carbon emission analysis of two typical denitrification systems for sintering process in the iron and steel industry

The transition of the Chinese iron and steel industry to ultralow emissions has accelerated the development of denitrification technologies. Considering the existing dual carbon targets, carbon emissions must be considered as a critical indicator when comparing denitrification systems. Consequently, this study provided a comprehensive cost-benefit model for denitrification in the steel industry, encompassing additional carbon emissions resulting from the implementation of denitrification systems. Activated-carbon adsorption and selective catalytic reduction (SCR) systems are two efficient techniques for controlling NOx emissions during sintering. Based on this model, a cost-benefit analysis of these two typical systems was conducted, and the results indicated that the unit flue-gas abatement costs of SCR and activated-carbon adsorption systems were 0.00275 and 0.0126 CNY/m3, and the unit flue-gas abatement benefits were 0.0072 and 0.0179 CNY/m3, respectively. Additionally, the effect of operational characteristics on operating costs, including duration and material prices, was analyzed. When treating the flue gas, the two systems released 0.0020 and 0.0060 kg/m3 of carbon dioxide, respectively. The primary sources of carbon emissions from the SCR and activated-carbon adsorption systems are the production of reducing agents and system operations, respectively. Furthermore, considering the features of the activated carbon adsorption system for simultaneous desulfurization, a SCR- wet flue gas desulfurization (WFGD) technology route was developed for comparison with the activated carbon adsorption system.

Structured query language query join optimization by using rademacher averages and mapreduce algorithms

Query optimization involves identifying and implementing the most effective and efficient methods and strategies to enhance the performance of queries. This is achieved by intelligently utilizing system resources and considering various performance metrics. Table joining optimization involves optimizing the process of combining two or more tables within a database. Structured query language (SQL) optimization is the progress of utilizing SQL queries in the possible way to achieve fast and accurate database results. SQL optimization is critical to decreasing the no of queries in research description framework (RDF) and the time for processing a huge number of relatable data. In this paper, four new algorithms are proposed such as hash-join, sort-merge, rademacher averages and mapreduce for the progress of SQL query join optimization. The proposed model is evaluated and tested using waterloo sparql diversity test suite (WatDiv) and lehigh university benchmark (LUBM) benchmark datasets in terms of time execution. The results represented that the proposed method achieved an enhanced performance of less execution time for various queries such as Q3 of 5362, Q8 of 5921, Q9 of 5854 and Q10 of 5691 milliseconds. The proposed gives better performance than other existing methods like hybrid database-map reduction system (AQUA+) and join query processing (JQPro).

Optimizing term rewriting with creeper trace transducers

In the context of functional programming/term normalization algorithms we discuss the optimization problem of constructing the result of a sequence of rewrite steps, without computing all the intermediate terms. From a rewrite system we construct a creeper trace transducer, which reads a sequence of backwards overlapping rewrite steps while producing the desired answer. The transducer writes each symbol of the output only once, skipping overlap between each pair of subsequent rules. In some cases a part of the trace can be disregarded altogether.

Sustainable strategies for recovering metallic copper from waste printed circuit boards: Clean leaching and micro-nano copper powder preparation

Recovery and utilization of valuable metals from waste printed circuit boards (WPCBs) have the dual significance of alleviating resource shortages and protecting the ecological environment. This study focuses on the feasibility analysis of copper in WPCBs for preparing micro-nano copper powders by clean leaching and chemical reduction processes. Firstly, the effect of temperature and other parameters on copper leaching rate in glycine-hydrogen peroxide (Gly-H2O2), ammonia-ammonium chloride (NH3·H2O-NH4Cl) leaching systems with sulfuric acid-hydrogen peroxide (H2SO4-H2O2) system as control group were emphasized. Subsequently, the leaching characteristics of copper concentrate particles were analyzed by leaching kinetics to elucidate the leaching mechanism and apparent activation energy of copper. Finally, the micro-nano copper powders were prepared using ascorbic acid and sodium borohydride reduction system with different copper leach solutions as precursors. The micro-nano copper morphology and phase compositions were analyzed by SEM and XRD. The results show that both the Gly-H2O2 and NH3·H2O-NH4Cl system can replace the H2SO4-H2O2 system to achieve efficient leaching of copper. Increasing temperature can significantly enhance the copper leaching rate. When the temperature was increased from 15 °C to 45 °C, the maximum copper leaching rate in the three systems increased from 58.13 %,71.26 %,78.26 % to 90.36 %,91.21 %,92.87 %, at − 0.074 mm for 40 min. The Avrami model accurately describes the leaching behavior of copper concentrate particles, and the copper leaching process is dominated by chemical reaction control. SEM and XRD results show that micro-nano copper particles of hundreds of nanometers are successfully prepared by both reduction systems.

Optimization of the Combined Ventilation System for Dust Reduction in Blind Headings of Potash Mines

Optimization of the Combined Ventilation System for Dust Reduction in Blind Headings of Potash Mines

Analysis of the use of logistics-telematics systems for cost reduction in a transport company

Purpose: The main purpose of this paper is to investigate the extent to which real-time monitoring of vehicles and the collection of operational data about them through telematic systems can contribute to the reduction of operating costs in a transport company. The study focuses on specific factors such as the driver's actions, which can affect the vehicle's technical condition and diesel consumption levels. Methodology: The research is based on an analysis of operational data obtained from the vehicles of a transport company engaged in international freight transportation. The data were primarily analyzed for an indicator related to total fuel (diesel) consumption while driving. Linear models were created using the least squares method, and the best-fitting models were selected to draw conclusions about the impact of telematic systems on the company's costs. Results: The study found that the introduction of a telematic system can have a positive impact on a transport company's operations and help reduce costs associated with the execution of transport orders. The analysis of the data showed that individual factors, such as driving time, average axle load, and average travel speed, can affect the total driving fuel consumption of all vehicles and contribute to the overall cost reduction. Theoretical contribution: This paper contributes to the understanding of the role of telematic systems in the optimization of fleet planning and management, which is a crucial aspect of the logistics of transporting goods. The research provides insights into the potential of real-time monitoring and data collection for improving the efficiency and cost-effectiveness of transport companies. Practical implications: The findings of this study can be useful for transport companies looking to improve their operations and reduce costs. The research highlights the importance of using telematic systems in the right way to carry out the transportation of goods and suggests that real-time monitoring and data analysis can be key to minimizing costs and maximizing profits.

Rational cross‐sections, bounded generation, and orders on groups

AbstractWe provide new examples of groups without rational cross‐sections (also called regular normal forms), using connections with bounded generation and rational orders on groups. Our examples contain a finitely presented HNN‐extension of the first Grigorchuk group. This last group is the first example of finitely presented group with solvable word problem and without rational cross‐sections. It is also not autostackable, and has no left‐regular complete rewriting system.

Optimization of superstructure network in the CCS/CCSU system for CO2 reduction from exhaust gas industry and gas field in Indonesia as archipelago state

Industrial exhaust gases and gas fields are two significant sources of carbon dioxide (CO2) emissions that contribute to the rising levels of CO2 in the atmosphere. Among the various emission reduction systems, the CCSU (Carbon Capture, Storage, and Utilization) system has garnered extensive attention and research. This research aims to obtain the superstructure network sequentially in the CCSU system using GAMS (General Algebraic Modeling System). A mathematical approach was developed to optimize the amount of CO2 stored and utilized by varying the time difference (dt) between the source and sink from 0 to 10 years. After calculating the economic potential (EP), it was found that the Carbon Capture and Storage (CCS) system for both sources has a negative impact. In contrast, the CCSU system enhances the economic potential (EP) by generating a positive value. This is possible as the captured CO2 can be sold to the utilization sink, thereby creating a revenue stream. The EP for CO2 reduction from gas fields is greater than that from the industry, 21.68 × 106 USD compared to 12.50 × 106 USD at dt min10 years. The CCSU system, when utilizing CO2 sources from gas fields, is more profitable compared to using industrial emissions.

An unmanned rice seeder with WiFi based mobile-control system for drudgery reduction

An unmanned rice seeder (URS) with WiFi based wireless communication system was developed to reduce surface seed dispersion, drudgery, human involvement, Occupational health hazards and environmental pollution. An android mobile phone with WIFI connectivity acts as wireless communication system to control the developed URS with operating range of 144.6 m which was surplus for small farms in hilly terrains of Sikkim. The factors of URS are found to be forward speed (Fs) and hopper fill level (HL) w.r.t responses of co-efficient of variation of number of seeds per hill (Cv), Seed rate (Sr), hill spacing uniformity (Us,), missing hill index (MI) and mean hill span (Hs). The optimum results of soil bin study are of Fs and HL of 2.4 km.h−1 and 75% w.r.t responses of Cv, Sr, MI, Us, Hs are 0.28, 18.5 kg. ha−1, 7.3%, 91.7%, and 6.4 cm. Test results showed that the seeding performance of developed seeder was similar to manual drum seeder. But, due to higher speed of operation in developed seeder showed better results in field operation. The results from the field evaluation revealed that URS has increase in field capacity of 41%, reduces labor requirement of 50% than manual rice seeder. In economic evaluation URS has reduced cost of operation (₹ ha−1) of 90% and increase net benefit (₹ year−1), Payback period of 61% and 91% over manual rice seeder (MRS). The operator's workload was decreased by up to 95% due to the machine's mobile operation as compared to the manual operation.

Construction of Bi2WO6/g-C3N4/Cu foam as 3D Z-scheme photocatalyst for photocatalytic CO2 reduction

Photocatalytic CO2 reduction to hydrocarbon fuels represents a promising solution to CO2 emission challenges. However, photocatalytic CO2 reduction systems face hurdles in practical utilization for the low efficiency of photocatalysts and challenge in catalyst immobilization. Therefore, a novel monolithic three-dimensional Z-scheme photocatalyst was synthesized by fabricating Bi2WO6/g-C3N4 heterojunction on Cu foam substrate (Bi2WO6/g-C3N4/Cu foam) via thermal polymerization and electrophoresis deposition. A series of characterization results, including X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and N2 adsorption–desorption, illustrate the crystalline properties, pore structure, and morphology of the composite photocatalyst. Consequently, Bi2WO6/g-C3N4/Cu foam achieved CO production yield of 33.84 μmol/g cat under visible light illumination for 6 h and retained 96.2 % of initial photocatalytic activity after 30 h of reaction. UV–Vis diffuse reflection spectra, photoluminescence spectra and photoelectrochemical analysis was involved to reveal the mechanism of the photocatalytic activity of composite photocatalyst.The synergistic effect of the Z-scheme mechanism and the hierarchical macroporous structure improves the light absorption, light-induced electron-hole pair separation, and charge transmission. This catalyst construction strategy provides a viable approach for facilitating practical photocatalytic CO2 reduction.

Combined Computational and Experimental Study Reveals Complex Mechanistic Landscape of Brønsted Acid-Catalyzed Silane-Dependent P═O Reduction.

The reaction mechanism of Brønsted acid-catalyzed silane-dependent P═O reduction has been elucidated through combined computational and experimental methods. Due to its remarkable chemo- and stereoselective nature, the Brønsted acid/silane reduction system has been widely employed in organophosphine-catalyzed transformations involving P(V)/P(III) redox cycle. However, the full mechanistic profile of this type of P═O reduction has yet to be clearly established to date. Supported by both DFT and experimental studies, our research reveals that the reaction likely proceeds through mechanisms other than the widely accepted "dual activation mode by silyl ester" or "acid-mediated direct P═O activation" mechanism. We propose that although the reduction mechanisms may vary with the substitution patterns of silane species, Brønsted acid generally activates the silane rather than the P═O group in transition structures. The proposed activation mode differs significantly from that associated with traditional Brønsted acid-catalyzed C═O reduction. The uniqueness of P═O reduction originates from the dominant Si/O═P orbital interactions in transition structures rather than the P/H-Si interactions. The comprehensive mechanistic landscape provided by us will serve as a guidance for the rational design and development of more efficient P═O reduction systems as well as novel organophosphine-catalyzed reactions involving P(V)/P(III) redox cycle.

Single-atom catalysis for advanced oxidation and reduction systems in water decontamination

Single-atom catalysis for advanced oxidation and reduction systems in water decontamination

Photocatalytic CO2 reduction of CuO-Zn1-xCuxO (ZCO)/Ti3C2Tx MXene heterojunctions with enhanced interfacial charge transfer

Photocatalytic CO2 reduction reaction (CO2RR) synthesis of recycled fuel is a promising pathway to assist the mitigating fossil fuel depletion. Finding efficient and inexpensive high performance CO2RR semiconductor photocatalysts is a giant challenge in the field of photocatalytic reduction. This work constructs the novel-designed interfacial Schottky junction of CuO-Zn1-xCuxO (ZCO)/Ti3C2Tx via electrostatic spinning and electrostatic self-assembly techniques. The catalysts exhibit tight contact heterogeneous interface companies with enhanced CO2 chemisorption capability and proved by various characterizations for efficient carrier separation and migration capacity. The optimized ZCO/Ti3C2Tx nanosheet composites significantly improved their photocatalytic performance. The best samples yielded 5.855 and 2.518 μmol g−1 h−1 of CO and CH4, which are 6 and 1.73 times higher than the conversion of ZCO, respectively, and maintain stability after four cycles without the use of sacrificial agents. In addition, the mechanism and reaction pathways of the photocatalytic process are proposed through In-situ diffuse reflectance Infrared Fourier Transform Spectroscopy (In-situ DRIFTS) and X-ray absorption near edge structure (XANES) analysis. This work provides a new semiconductor/co-catalyst system for the photocatalytic reduction of CO2 and demonstrates that Ti3C2Tx MXene is a hopeful and inexpensive co-catalyst.

Synthesis of core–shell silicon–carbon nanocomposites via in-situ molten salt-based reduction of rice husks: A promising approach for the manufacture of lithium-ion battery anodes

Silicon (Si) has gained substantial interest as a potential component of lithium-ion battery (LIB) anodes due to its high theoretical specific capacity. However, conventional methods for producing Si for anodes involve expensive metal reductants and stringent reducing environments. This paper describes the development of a calcium hydride (CaH2)–aluminum chloride (AlCl3) reduction system that was used for the in-situ low-temperature synthesis of a core–shell structured silicon–carbon (Si–C) material from rice husks (RHs), and the material was denoted RHs-Si@C. Moreover, as an LIB anode, RHs-Si@C exhibited exceptional cycling performance, exemplified by 90.63 % capacity retention at 5 A g−1 over 2000 cycles. Furthermore, the CaH2–AlCl3 reduction system was employed to produce Si nanoparticles (Si NPs) from RHs (R-SiO2, where SiO2 is silica) and from commercial silica (C-SiO2). The R-SiO2-derived Si NPs exhibited a higher residual silicon oxides (SiOx) content than the C-SiO2-derived Si NPs. This was advantageous, as there was sufficient SiOx in the R-SiO2-derived Si NPs to mitigate the volumetric expansion typically associated with Si NPs, resulting in enhanced cycling performance. Impressively, Si NPs were fabricated on a kilogram scale from C-SiO2 in a yield of 82 %, underscoring the scalability of the low-temperature reduction technique.