Product Yield Research Articles

Evaluating the sustainability of microwave pre-cured high-volume slag concrete: Mechanical properties, environmental impact and cost-benefit analysis

Microwave pre-curing, a novel method, offers numerous advantages including energy and time efficiency. The mechanical performance and durability of high-volume slag concrete (HVSC) subjected to microwave curing were experimentally investigated in this study. Additionally, the environmental impact and cost-effectiveness of microwave-cured HVSC were studied, and the ecological efficiency and cost efficiency were analyzed in conjunction with compressive strength and durability. Experimental results indicate that microwave curing significantly enhances the early-stage hydration reaction rate of concrete, increasing the yield of hydration products, especially AFm. Consequently, the early-stage porosity decreases, and the early compressive strength and electrical resistivity of the mortar increase significantly. Furthermore, microwave curing significantly improves the early-stage ecological efficiency and cost efficiency of HVSC. Although the ecological efficiency and cost efficiency of later-stage strength decrease slightly, the durability ecological efficiency and cost efficiency have increased by 12.41–24.6 % and 13.79–26.89 %, respectively, compared to the control group. Time-saving analysis indicates that microwave curing can significantly reduce the curing time for samples by quickly enhancing the early mechanical properties of the materials. Specifically, microwave curing can shorten the curing time by 2.09 days when the compressive strength requirement reaches 20 MPa, and by 2.62 days when the requirement is 30 MPa.

Calcium single atoms stabilized by nitrogen coordination in metal–organic frameworks as efficient solid base catalysts

Considerable attention has been paid to the preparation of single-atom solid base catalysts (SASBCs) owing to their high activity and maximized utilization of basic sites. At present, the reported fabrication methods of SASBCs, such as two-step reduction strategy and sublimation capture strategy, require high temperature. Such a high activation temperature is easy to cause the sublimation loss of alkali or alkaline earth metal atoms and destructive to the support structure. Herein, a new SASBC, Ca1/UiO-67-BPY, is fabricated, in which the alkaline earth metal Ca sites are immobilized onto N-rich metal–organic framework UiO-67-BPY at room temperature. The results show that the atomic configuration of Ca single atoms is coordinated by two N atoms in the framework. The obtained Ca SASBC possesses ordered structure and exhibits high product yield of 87.2% in the Knoevenagel reaction between benzaldehyde and malononitrile. Furthermore, thanks to the Ca single atoms sites anchored on UiO-67-BPY, the Ca1/UiO-67-BPY catalyst also shows good stability during cycles. This work might offer new insight in designing SASBCs for different base-catalyzed reactions.

Clostridium autoethanogenum alters cofactor synthesis, redox metabolism, and lysine-acetylation in response to elevated H2:CO feedstock ratios for enhancing carbon capture efficiency

BackgroundClostridium autoethanogenum is an acetogenic bacterium that autotrophically converts carbon monoxide (CO) and carbon dioxide (CO2) gases into bioproducts and fuels via the Wood–Ljungdahl pathway (WLP). To facilitate overall carbon capture efficiency, the reaction stoichiometry requires supplementation of hydrogen at an increased ratio of H2:CO to maximize CO2 utilization; however, the molecular details and thus the ability to understand the mechanism of this supplementation are largely unknown.ResultsIn order to elucidate the microbial physiology and fermentation where at least 75% of the carbon in ethanol comes from CO2, we established controlled chemostats that facilitated a novel and high (11:1) H2:CO uptake ratio. We compared and contrasted proteomic and metabolomics profiles to replicate continuous stirred tank reactors (CSTRs) at the same growth rate from a lower (5:1) H2:CO condition where ~ 50% of the carbon in ethanol is derived from CO2. Our hypothesis was that major changes would be observed in the hydrogenases and/or redox-related proteins and the WLP to compensate for the elevated hydrogen feed gas. Our analyses did reveal protein abundance differences between the two conditions largely related to reduction–oxidation (redox) pathways and cofactor biosynthesis, but the changes were more minor than we would have expected. While the Wood–Ljungdahl pathway proteins remained consistent across the conditions, other post-translational regulatory processes, such as lysine-acetylation, were observed and appeared to be more important for fine-tuning this carbon metabolism pathway. Metabolomic analyses showed that the increase in H2:CO ratio drives the organism to higher carbon dioxide utilization resulting in lower carbon storages and accumulated fatty acid metabolite levels.ConclusionsThis research delves into the intricate dynamics of carbon fixation in C. autoethanogenum, examining the influence of highly elevated H2:CO ratios on metabolic processes and product outcomes. The study underscores the significance of optimizing gas feed composition for enhanced industrial efficiency, shedding light on potential mechanisms, such as post-translational modifications (PTMs), to fine-tune enzymatic activities and improve desired product yields.

In-situ construction of N-doped Zn0.6Cd0.4S/oxygen vacancy-rich WO3 Z-scheme heterojunction compound for boosting photocatalytic hydrogen production

Photocatalytic water splitting technology for H2 production represents a promising and sustainable approach to clean energy generation. In this study, a high concentration of oxygen vacancies was introduced into tungsten trioxide (WO3) to create a vacancy-rich layer. This modified WO3 (WO3-x) was then combined with N-doped Zn0.6Cd0.4S through a hydrothermal synthesis, resulting in the formation of a Z-scheme heterojunction composite aimed at enhancing photocatalytic performance. Under visible light, the H2 production activity of the composite reached an impressive 8.52 mmol·g−1 without adding co-catalyst Pt. This corresponds to enhancements of 7.82 and 4.39 times the production yield of pure ZCS and ZCSN, respectively. However, the hydrogen production increased to 21.98 mmol·g−1 when Pt was added as a co-catalyst. Furthermore, an array of characterizations were employed to elucidate the presence of oxygen vacancies and the establishment of the Z-scheme heterojunction. This structural enhancement significantly facilitates the utilization of photo-generated electrons while effectively preventing photo-corrosion of ZCSN, thus improving material stability. Our study provides a new scheme for the incorporation of oxygen-rich vacancy and the construction of Z-scheme heterojunction, demonstrating a synergistic effect that greatly advances photocatalytic performance.

SO2 removal performance and breakthrough prediction of activated carbon-based chemical filters for electronics cleanroom air purification

Electronic cleanrooms have strict control requirements for SO2 concentration due its significant influence on product yield, and application of chemical filters is the main measure of SO2 control. In this study, 8 activated carbon (AC)-based chemical filters were collected and tested for their SO2 purification performance and resistance. These filters had very similar initial efficiencies (all >95 %) but large differences in 20 % breakthrough adsorption capacity (49–294 g at 9 ppm and 0.35 m/s). The adsorption capacity is found to be positively correlated with pleat density, which is a main structural parameter of pleated chemical filter. Meanwhile, the filter resistance (9.3–34 Pa at 0.35 m/s) demonstrates a decreasing and then increasing trend with increasing pleat density. This indicated the existence of an optimal range of pleat numbers that can be used to achieve a balance between resistance and adsorption capacity. A comprehensive performance evaluation index (Z′-index) is proposed for assessing the integrated resistant and adsorption capacity performance of chemical filters (19–210 g/W for 8 samples). A lumped parameter model was proposed for predicting the breakthrough curves at low concentration based on the traditional semi-empirical breakthrough models. The prediction deviation of the breakthrough curve at real cleanroom scenario (2 ppb) is less than 15 %. In addition, a rapid filter life prediction method based on filter design parameters is developed from the lumped parameter model. This work helps the understanding of the impact of filter structure parameters on performance and facilitate the development of high-performance chemical filters for SO2 contaminant control in electronic cleanrooms.

Manipulating Photoconduction in Supramolecular Networks for Solar-Driven Nitrate Conversion to Ammonia and Oxygen.

For photoelectrodes to be used in practical catalytic applications, challenges exist in achieving the efficient production and transport of photogenerated charge-separated states. Analogous concepts in traditional inorganic photoelectrodes can be applied to their organic-polymer counterparts with improved charge-separation efficiencies. In this work, we develop photoconductive organic networks to form a high-performance photoelectrode for NO3- reduction to NH3. In the integrated network, interfaces between the organic electron-donating photoconductor and electron-accepting catalyst can generate charge carriers efficiently upon illumination, leading to enhanced charge separation for photoelectrocatalysis. The photoelectrode network is capable of converting NO3- to NH3 at an external quantum efficiency of 13%. By coupling with a BiVO4 photoanode in tandem, the system reduces NO3- to NH3 and oxidizes H2O to O2 simultaneously at Faradaic efficiencies of 95-98% with sustained photocurrents and production yields. Investigation of the photoconductive network by steady-state/time-resolved spectroscopies reveals the efficient generation and transport of free charge carriers in the photoelectrode, providing a basis for high photoelectrocatalytic performances.

Correlation between perennial grass productivity and landscape and climatic conditions

The yield monitoring (1998–2023) of cloverothymothy grass stands of 1 year of use within the moraine hill was carried out in order to find patterns in the influence of weather conditions on it. The grass stands were operated in the conditions of the Tver region without fertilizers in a single-cut mode on a field divided into 120 plots. Using regression analysis, we determined the influence of temporal variability of average monthly values: average daily temperatures, their amplitude, amount of precipitation and hydrothermal coefficient on the hay yield of perennial grasses. It was revealed that in total these parameters determine about 43% of the variability in grass productivity, but fluctuations in temperature amplitudes are responsible for 32% of the temporal variability of the yield. The yield of herbs is affected by the variability of growing conditions not only in time, but also in space. The negative impact on the yield of air temperature changes is observed in all parts of the landscape, except for the flat top, where productivity responds positively to the growth of the hydrothermal coefficient and negatively to the increase in air temperatures in the pre-harvest period. The following have a negative impact on product yield: temperature changes in late summer and early autumn, especially on southern slopes, which can make it difficult for plants to overwinter; thaws in March, causing the formation of an ice crust on the soil surface and damaging the tillering nodes of plants; hot days in the pre-harvest period, accelerating the ripening of grasses and reducing the intensity of biomass accumulation. February thaws, promoting the accumulation of moisture in the soil, lead to an increase in grass yield. Measures that reduce the negative impact of temperature changes on the grass harvest include: autumn mowing of young grass, snow retention in meadows, and sprinkling of grass on the hottest days of the pre-harvest period.

Microprocessor Control of the Electric Drive of Variable Radiation Installation and Ensuring of Operation Reliability

Introduction. The introduction of energy-saving technologies has become particularly relevant in recent years, when energy prices have been constantly increasing. This is particularly important for greenhouse farms, where the main condition for growing plants indoors is the creation of artificial climatic conditions: temperature, humidity, and lighting.Problem Statement. Given the light and the dark stages of photosynthesis, it becomes possible to use a variable light field in the plant-growing photoculture, which is created by light installations with variable radiation. The development of an energy-saving electric drive and automated control systems for the parameters of artificial climatic conditions when growing plants indoors results in reducing energy consumption and increasing the reliability of the technological process in greenhouses of agro-industrial complex.Purpose. Implementation of energy-saving variable illumination irradiating systems with an automated control system for greenhouse farms.Materials and Methods. A lighting installation with rotation of the irradiator in the vertical and horizontal planes with a discrete electric drive and microprocessor control has been used.Results. The current state of variable irradiating systems with energy-saving radiation sources has been analyzed. The use of a discrete electric drive with an automated control system has been proposed. The installation with a DNAT-400 radiation source and a ZHO-01 reflector enables irradiating an area of up to 100 m2. The maximum exposure to photosynthetically active radiation is 30 W/m2, and the irradiation irregularity does not exceed 20%. At the same time, electricity savings reach about 10 thousand kWh per season. The yield and quality of products remain unchanged.Conclusions. The results of the research have confirmed the feasibility of practical implementation of variable irradiation system for energy efficiency of greenhouse operations.

The influence of soybean rhizobia on the agricultural seeds sowing qualities

To grow high and stable yields with good product quality, it is very important to receive timely, full-fledged and friendly shoots of optimal density. Therefore, the problem of stimulating, or inhibiting, seed germination and the processes occurring in them occupies an important place in modern crop production. The method of pre-sowing seed treatment with rhizobia is one of the promising technological measures that ensure an increase in yield and quality of crop production. The staff of the Laboratory of Biological Research of the Federal State Budgetary Budgetary Institution of the Federal Research Institute of Soy conducted a study of the possibility of stimulating germination and disinfection of soybean seeds, lupin, vigna, wheat, barley using pure Sinorhizobium fredii crops. The work used collectible strains of rhizobia, which showed an abundant growth of bacterial mass on the nutrient medium of the MRC. The standard strain was S. fredii 5851 from the collection of microorganisms and cell cultures of the Leibniz Institute (DSMZ), Germany. In variants with strains, stable stimulating and healing effects were observed. As a result of a scientific experiment, it was found that, on average, in variants with S. fredii strains, germination increased by 37%, the length of seedlings – by 224%, the raw weight of seedlings – by 23% compared with the control (without treatment with strains). S. fredii strains BB-49, SB-39, SB-43, TB-422, TB-488, TB-490, TB-496, 062 maximally stimulated the process of germination of agricultural seeds.

Chiral Binaphthol-Catalyzed Enantioselective Conjugate Addition of Alkenyl and Arylboronic Acids to α,β-Unsaturated Cyclic N-Sulfonyl Ketimines.

The chiral binaphthol-catalyzed enantioselective conjugate addition of alkenylboronic acids and heteroarylboronic acids to cyclic N-sulfonyl ketimines is reported, providing the 1,4-addition products in high yields and moderate to excellent enantioselectivities (up to >99% ee). This mild, scalable catalytic system exhibits high efficiency and broad substrate scopes. Additionally, arylboronic acids were viable nucleophiles under more forcing conditions.

Ru(II)‐Catalyzed Weak Chelation‐Assisted Regioselective C4−H Aminomethyl Alkenylation of Indole

A Ruthenium catalyzed C4‐ aminomethyl alkenylation of indoles using substituted propargylamine as an alkenylating agent and pivaloyl as a weak chelating group has been demonstrated. A variety of substituted indoles and propargylamines furnished the desired product in good yields. Control experiments indicate that the C−H cleavage step is reversible and suggest the possibility of a base‐assisted internal electrophilic substitution (BIES) pathway.

Interaction Effects of Water and Nitrogen Practices on Wheat Yield, Water and Nitrogen Productivity under Drip Fertigation in Northern China

Water resource shortage and unreasonable application of nitrogen (N) fertilizer have been problems in wheat production of northern China. However, the interaction effects of water regimes and N practices on wheat root growth, grain yield, soil water, and inorganic N changes as well as water-N use efficiency are still unclear under drip irrigation. A field experiment was conducted during the 2020–2021 and 2021–2022 winter wheat (Triticum aestivum) growing seasons. In this study, three irrigation schedules (i.e., irrigation was applied up to 80% [D1], 75% [D2], and 70% [D3] as soon as the soil water content decreased to 65%, 60% or 55% of field capacity) and two N practices (i.e., N applied at the base, jointing, booting stages were 90, 72, 48 kg ha−1 [N1], and the base, jointing, booting, filling stages were 90, 40, 40, 40 kg ha−1 [N2], respectively) were considered. The decease in irrigation water amount was offset by the increase in soil water consumption. In addition, N practices significantly interacted with irrigation on soil NO3−–N accumulation (2021–2022), NH4+–N accumulation, SPAD value (2020–2021), N content in stems and grains at maturity, and average root length and weight density at the flowering stage. Irrigation, rather than N practices, significantly affected grain yield, total N uptake, crop N transformations (NT), the contribution of NT to grain (NTPC), water and N productivity, in which, for the value of these two seasons, D2 increased total N uptake by 18.1% (p < 0.05), and NT by 39.4% (p < 0.05) under N1 as compared to D3. Additionally, the highest WUE and ANUE were found in D2 during 2021–2022. Heavy irrigation water amount caused high a LAI; further analysis proved that the LAI was the key factor affecting grain yield, and positively and significantly correlated to yield. However, no significant difference in the LAI between D1 and D2 was found. N1 was beneficial to prevent N leaching and increase water and N use efficiency, biomass, and N transformation amount. This study recommends that D2 + N1 might be a promising system for manipulating irrigation and fertilization practices under sub-surface drip irrigation systems to improve water and N use efficiency and grain yields in semi-arid regions.

The comparative techno-economic and life cycle assessment for multi-product biorefinery based on microwave and conventional hydrothermal biomass pretreatment

Microwave as an efficient and clean energy, is easy integrated with DES pretreatment and biorefinery process to achieve process intensification for cleaner production and sustainable development. However, there are worries about its economic and environmental feasibility for application in biorefinery plant. This work conducted the techno-economic (TEA) and life cycle assessment (LCA) of the entire biorefinery process based on DES pretreatment by microwave heating (MH) for producing glucose, furfural and lignin from lignocellulose, of which the results were compared with conventional heating (CH). For pretreating equivalent biomass, the total yield of products obtained from MH-assisted process was 8.53% higher than that of CH-assisted process due to microwave intensification effect. From the perspective of cradle-to-gate LCA, the MH-assisted process saved energy demand of 5.82%, reducing the environmental impacts global warming (GW) and fossil resource scarcity (FRS) by 4.85% and 5.69%, respectively, relative to CH-assisted process. The main environmental hotspots of both two processes concentrated on the raw material extraction (RME), followed by product separation and solvent recovery (PSSR) stages. Based on economic evaluation, the specific values of TAC regarding one-ton product for MH- and CH-assisted processes were 3194.35 and 3400.37 $/(y⋅t), respectively. Therefore, the MH-assisted pretreatment possessed certain environmental and economic advantages due to product increasement, energy consumption reduction in the DES pretreatment, and burden reduction for subsequent enzyme hydrolysis. Compared to the single-product biorefinery, the multi-product biorefinery strategy was more sustainable and could maximize the advantages of microwave intensification. However, some issues about the design of microwave reactors and temperature monitoring must be considered to pursue scale-up biorefinery plant.

A novel turn-off green carbon dot-based fluorescent probe for selective determination of nitrazepam in its pharmaceutical dosage form and milk samples.

In this study, a new, rapid, simple, and cost-effective fluorescent probe based on carbon dots (CDs) has been developed for the selective determination of nitrazepam (NZP). The CDs were synthesized with high production yield (71.43%) through one step carbonization of dried banana peels. The fluorescence intensity of the CDs is quenched by increasing the NZP concentration as a result of the inner-filter effect and dynamic quenching mechanism. This fluorescent sensor effectively quantified NZP in the linear range of 0.30-26 μg mL-1, with a limit of detection of 0.10 μg mL-1. The performance of the sensor was validated according to ICH guidelines and exhibited high precision and accuracy. The proposed method was also successfully extended for determining NZP in tablet dosage form and milk samples.

13C-labelled Glucose Reveals Shifts In Fermentation Pathway During Cathodic Electro-Fermentation With Mixed Microbial Culture.

Cathodic Electro Fermentation (CEF) is an innovative approach to manage the spectrum of products deriving from anaerobic fermentation. Herein, mixed microbial culture fermentation using a ternary mixture containing labelled 13C glucose and non-labelled acetate and ethanol was studied to identify the role of polarization on the metabolic pathways of glucose fermentation. CEF at an applied potential of -700 mV (vs. SHE, Standard Hydrogen Electrode) enhanced the production yield of acetate, propionate, and butyrate (0.90 ± 0.10, 0.22 ± 0.03, and 0.34 ± 0.05 mol/mol; respectively) compared to control tests performed at open circuit potential (OCP) (0.54 ± 0.09, 0.15 ± 0.04 and, 0.21 ± 0.001 mol/mol, respectively). Results indicate that CEF affected the 13C labelled fermented product levels and their fractional 13C enrichments, allowing to establish metabolic pathway models. This work demonstrates that, under cathodic polarization, the abundance of both fully 13C labelled propionate and butyrate isotopomers increased compared to control tests. The effect of CEF is mainly due to intermediates initially produced from the glucose metabolic transformation in the presence of non-labelled acetate and ethanol as external substrates. These findings represent a significant advancement in current knowledge of CEF, which offers a promising tool to control mixed cultures bioprocesses.

Propose and implement a Rule-Based System to Predict Crop Yield Production

Accurate meteorological forecasting plays a pivotal role in agricultural decision-making, particularly in determining crop yield potential and optimizing agricultural practices. This study investigates the application of data mining techniques in meteorological forecasting to enhance crop yield prediction accuracy Preliminary findings suggest that data mining techniques, including machine learning algorithms, neural networks, and ensemble methods, offer significant potential for improving the accuracy and reliability of meteorological forecasts for crop yield prediction. In conclusion, this study underscores the potential of data mining techniques in improving meteorological forecasting for crop yield potential assessment.

Modification and Screening of Antibiotic-producing Strains

Antibiotics play an important role in the field of medicine and healthcare, and with increasing usage, there is an urgent need to improve the quality and yield of antibiotic products to achieve cost reduction and efficiency. This has forced scientists to modify and screen antibiotic-producing strains to improve the yield and quality of antibiotic products. This paper briefly describes the strain modification methods as well as strain screening methods, discusses the limitations of each method, and looks forward to the development trend of strain modification and screening.

Synthesis of 5-substituted-1H-tetrazoles by lemon juice as a homogeneous and natural catalyst under green reaction conditions

Tetrazole, as a heterocyclic compound, exhibits a wide spectrum of applications in various industries. This research focuses on utilizing a natural catalyst in the synthesis of tetrazole derivatives. Leveraging the acidic nature of lemon juice (LJ), we employed it as a potential catalyst in the synthesis of 5-substituted-1H-tetrazole. LJ would act as the reaction medium as well. This synthesis involves the cycloaddition reaction (3+2) of sodium azide to benzonitrile under solvent-free conditions. Optimization of the reaction conditions including temperature, reaction time, and solvent type was tuned towards the highest yield considering the mild reaction time. The best product yield (97%) was obtained at 90°C, 40 min, in the absence of additional solvent. Various benzonitrile derivatives were examined at the optimized reaction condition.

Tailoring the properties of carbon molecular sieves membranes for the separation of propionic acid from aqueous solutions

In the fermentative production of propionic acid (PA), the major problem with batch fermentation systems is the strong inhibitory effect of PA on the production yield; one way to increase the yield is the in-situ removal of PA by using pervaporation. Acetic acid (AA) is the most important by-product in the fermentation; therefore, the membrane should be able to remove selectively PA from an aqueous solution containing AA. Considering that PA is more hydrophobic than AA and their kinetic diameter are 0.480 and 0.436 nm respectively, hydrophobic membranes with main pores in the range of around 0.5–0.6 nm with high permeation are required.Supported thin Carbon Molecular Sieve Membranes (CMSM) were prepared by the dip coating a porous alumina support into a solution containing resorcinol phenolic resin as carbon source. The hydrophobicity was obtained by carbonizing the polymer at temperatures higher than 750 °C and adding polyvinyl butyral (PVB) as pore forming agent and carbon contributor. PA with 88 % of purity was obtained by pervaporation of an aqueous solution containing 5 % of PA and 5 % of AA using a CMSM carbonized at 850 °C containing 1 % of PVB in the dipping solution.

Data-driven modeling of bio-oil yield in agricultural biomass pyrolysis with machine learning

Abundant amounts of solid waste are produced due to the processing of various agricultural goods, such as garbage incineration. This agricultural waste management strategy causes a significant increase in air pollution and environmental deterioration. Several methods are widely applied to treat agricultural waste; the pyrolysis process, which includes burning biomass feedstocks without oxygen, is one of the most recommended. Pyrolysis of agricultural waste can produce biochar, bio-oil, and syngas. Pyrolysis is a complicated procedure that depends on feedstock characteristics such as feed composition (i.e., carbon, hydrogen, and oxygen elemental composition), fixed carbon, and volatile matter. Investigation of the individual property of the feedstock on the overall product yield by experimental or computational study is laborious and time-consuming. Therefore, the machine learning technique is applied in this paper to develop a robust and accurate model to predict the agricultural waste bio-oil yield. A total of 387 data points are gathered from various literature sources. This paper utilizes the proximate analysis, ultimat analysis of the agricultural feedstock, and pyrolysis reaction conditions as input features. Eight different machine-learning algorithms, i.e. adaptive boosting, artificial neural network, categorical boosting, decision tree with bagging, k nearest neighbor, light gradient boosting, random forest, and extreme gradient boosting are deployed for this objective. In addition, a SHAP analysis with a bar plot and a beeswarm plot is built to identify the input variables that had the greatest impact on bio-oil production. The categorical boost model gave the lowest root mean squared error of 2.65 out of all the models and had the greatest R2 value of 93.2% on the testing dataset. The SHAP analysis of the developed model for identifying the feature importance and the beeswarm plot is also performed, which shows that for the pyrolysis of agricultural waste, the hydrogen content is one of the most crucial parameters for the maximization of bio-oil yield.