Reduction Behavior Research Articles

Collaborative pollution and carbon reduction behaviors of carbonated Pb-contaminated soil stabilized with a low-carbon binder derived from waste concrete

Due to the limited hydration capacity, solidification/stabilization (S/S) with waste concrete powder (WCP) has a low strength. Carbonation can reduce carbon dioxide (CO2) emissions and improve strength of lead-contaminated soil, but its mechanism and environmental behaviors are unclear. In light of this, a comprehensive study was conducted on the compressive strength, lead immobilization, conductivity characteristics, and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600 °C WCP. Results indicated that with carbonation, the compressive strength of the samples was significantly improved at the early stage (1 d), resulting in increased unconfined compressive strength (UCS) by 2.5-5.2 times due to the filling of pores by calcite. It negatively affected the lead immobilization capacity of highly doped (30%) samples, while this effect reversed after 3 d of carbonating due to the reduced alkaline environment. The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide ((PbCO3)2Pb(OH)2). The water evaporation (saturation <16.8%) led to dry shrinkage cracking and decreased UCS of the samples. Based on this finding, a conductivity model was developed for carbonated and cured samples, accurately predicting changes in saturation levels (R2 = 0.98). A relationship between conductivity and UCS or lead immobilization capacity was proposed. This research proposed an innovative method for the reduction of CO2 emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.

Analytical model for concrete crack width of steel lined reinforced concrete penstock

Cracking in steel lined reinforced concrete penstock (SLRCP) poses substantial challenges to both serviceability and safety, particularly when crack width exceeds specified limits. Despite its critical implications, accurately calculating crack width remains a persistent challenge. To address this issue, a multi-layer steel-concrete ring analytical model is derived through the concept of orthotropic and thick-walled cylinder theories. In this model, the cracked concrete is assumed to be an orthotropic material incorporating both elastic modulus reduction and tensile softening behavior based on its cracking characteristic of radial penetrating cracks uniformly distributed on the circumference. The steel liner and reinforcing steel bar are modeled as continuous steel rings using equivalent stress theory, while thick-walled cylinder theory is applied due to geometric features and bearing characteristics. Crack width is determined through equilibrium of force and compatibility of deformations at steel-concrete interfaces, utilizing these assumptions and the developed calculation model. To validate the proposed model, data from prototype observations and large-scale model tests of SLRCPs were systematically collected. The crack width results obtained from the proposed model exhibit strong agreement with the collected data, confirming its accuracy and reliability. In conclusion, the proposed analytical model provides an effective solution for calculating the crack width of SLRCP and offers valuable insights for durability evaluation.

Towards Integration of Ni-Slag Cleaning Process and Lithium-Ion Battery Recycling for an Efficient Recovery of Valuable Metals

Spent lithium-ion batteries (SBs) are important sources of valuable and critical raw materials. An integration of battery recycling with well-established primary processes for metals production has many advantages. In this work, the recycling of two battery scrap fractions obtained from mechanical pretreatment was integrated with a Ni-slag cleaning process at laboratory scale. Graphite from SBs acted as the main reductant, and the reduction behavior of major and trace elements was investigated as a function of time at 1350 °C. Major CO and CO2 concentrations, as well as minor amounts of SO2, NO2, CH4, and C2H4, were detected in the off-gas line. The evolution of gases took place within the first minutes of the experiments, which indicated that metal oxide reduction reactions as well as decomposition of the organic binders both happened very rapidly. This result is in line with the analytical results obtained for the slag phase, where the most significant metal oxide reduction was observed to take place within the first 5 to 10 minutes of the experiments. The distribution coefficient values for Co and Ni between metal alloy and slag as well as between matte and slag showed no significant differences when battery scrap fractions with different compositions were used. The addition of Ni-concentrate in the starting mixture resulted in increasing recoveries of Ni and Co, as well as improved settling of the matte phase.

Effect of wall length on an interacting supersonic rectangular jet

PurposeThis study aims to study the interaction effects between a rectangular supersonic jet with a flat wall computationally using wall length as a parameter. The purpose of this study is to investigate the effect of change in wall length on supersonic core length (SCL) reduction, jet deflection and jet decay behavior.Design/methodology/approachThe design Mach number and aspect ratio at the rectangular exit were 1.8 and 2, respectively. To study the wall length effects on jet-wall interactions, wall length (Lw) was varied as 0.5Dh, 1Dh, 2Dh, 4Dh and 8Dh, where Dh was the hydraulic diameter of the nozzle exit. The flat wall with the matching width of the rectangular exit section of a supersonic nozzle was placed at the nozzle exit such that the supersonic jet grazed past the wall. The studies were carried out at over-expansion [nozzle pressure ratio (NPR) = 4], near optimum expansion (NPR = 6) and under-expansion (NPR = 8) levels.FindingsResults indicated that significant reduction in wall-bounded SCL was noticed in the range of 0.5Dh ≤ Lw ≤ 1Dh for both over-expansion and under-expansion conditions. At Lw ≥ 4Dh, SCL got enhanced at NPR = 4 and 6 but had a negligible effect at NPR = 8.Practical implicationsThrust vector control, noise reduction and easy take-off for high-speed aircraft.Originality/valueThe effect of change in flat wall length on interaction characteristics of a rectangular supersonic jet was not studied before in terms of SCL reduction and jet decay behavior.

The Reduction Reaction Behavior of Steelmaking Dusts with Lignin under Different Atmospheres.

This study investigated lignin as a reducing agent instead of fossil carbon for the reduction of zinc oxide and zinc ferrite contained in steelmaking dusts. Three types of dusts from different steelmaking processes were considered: ferrochrome converter (CRC), electric arc furnace stainless steel (EAFSS) and electric arc furnace carbon steel (EAFCS). Zinc is primarily found in zincite phases within CRC dust, while EAFSS and EAFCS dusts contain franklinite and zincite phases as Zn-bearing minerals. The proximate analysis of lignin showed that the fixed carbon content is 28.9%. Thermogravimetric (TG) analysis coupled with differential scanning calorimetry (DSC) and mass spectrometry (MS) was used to study the reduction behavior of different mixtures of lignin and steel dusts under inert and air atmospheres. Simultaneously, the minimum ratio of lignin out of three different proportions required to achieve a complete reduction of franklinite and zincite phases into metallic zinc was identified. The results indicated that a 1.1 stoichiometric amount of lignin is sufficient for the complete reduction of zinc-bearing minerals into metallic zinc. In conclusion, lignin can be used efficiently for processing steelmaking dusts.

Hydrogen Reduction Behavior and Microstructure Characteristics of WO3-NiO-CuO Powder Mixture

The characteristics and hydrogen reduction behavior of W-0.8 wt% Ni-0.4 wt% Cu powder synthesized from WO3-NiOCuO composite powder have been investigated. The metal oxide powder mixtures were prepared using a ball milling process. XRD analysis and HR-TEM revealed that the oxide powders are changed to W and CuNi alloy powders with an average particle size of about 100 nm by hydrogen reduction. To understand the reduction behavior of oxide powders, TG analysis was performed, and the reduction kinetics was evaluated by the amount of peak shift with heating rates. The activation energies for the reduction of WO3-NiO-CuO, estimated by the slope of the Kissinger plot, were measured as 60.6-114.4 kJ/mol depending on reduction steps.

Study on the Effect of Digital Technology Adoption and Farmers’ Cognition on Fertilizer Reduction and Efficiency Improvement Behavior

Based on the field survey data for 1216 apple growers in three provinces from China’s Loess Plateau Region, this paper adopted Multivariate Probit (MVP) model and intermediary effect model to analyze the influence mechanisms of digital technology adoption (DTA) on farmers’ choices of Fertilizer-reduction and Efficiency-improving Technologies (FETs) from the perspective of farmers’ cognition (FC). The correlation effects of three typical FETs of soil testing and formula fertilization, integrated water-fertilizer fertilization and slow/controlled release fertilizer, were tested empirically. The results showed that DTA could significantly affect the adoption of FETs by apple growers, and FC played a partial mediating role, and there were complementary effects among the three typical FETs. The results were further confirmed by the propensity score matching (PSM) robustness test and the instrumental variable (IV) endogeneity test conducted in the conditional mixed-process (CMP). The results of our heterogeneity analysis showed that the promotion effect of DTA on FETs in the group with junior high school education or below was more significant than that in the group with higher education, and the promotion effect was more significant in the group with large operation scale. Therefore, the improvement in Internet penetration should not be taken as the ultimate goal, but more attention should be paid to farmers’ mastery and effective use of DTA, promote the improvement in farmers’ cognitive level, and implement the “bundled” publicity and guidance strategy of FETs adoption, so as to help in the green transformation of agriculture.

Constructing Ni-Pt Bimetallic Catalysts for Catalytic Hydrogenation and Rearrangement of Furfural into Cyclopentanone with Insight in H/D Exchange by D2O Labeling.

Developing a metallic catalyst for converting furfural (FAL) to highly valuable products such as cyclopentanone (CPO) is important for fine chemical synthesis by the efficient utilization of biomass resources. The presence of diverse unsaturated carbon atoms in FAL and the rearrangement of oxygen atoms hinder the production of CPO. We developed an optimal nickel (Ni)-to-platinum (Pt) molar ratio (1:0.007) for a bimetallic Ni-Pt/alumina (Al2O3) catalyst with a low Pt loading via an impregnation method to efficiently catalyze the selective hydrogenation of FAL in an aqueous solution to form CPO. The comprehensive characterizations by X-ray diffraction and X-ray absorption near edge structure analyses elucidated the formation of Ni0/Pt0 and Ni2+/Pt4+ after reduction by H2. The addition of a low amount of the Pt-Ni/Al2O3 catalyst resulted in an alleviation of H2 reduction behavior detected by hydrogen temperature-programmed reduction, accompanied by low H2 desorption ability observed by hydrogen temperature-programmed desorption. The catalytic activity of Ni-Pt/Al2O3 was higher than those of Ni/Al2O3 and Pt/Al2O3 catalysts. The maximum CPO yield was 66% with 93% FAL conversion under the optimized conditions (160 °C, 20 bar of H2 pressure, and 2 h). Isotopic deuterium oxide (D2O) labeling revealed the transfer of deuterium (D) atoms from D2O to the intermediates and products during hydrogenation and rearrangement, which confirmed that water was a medium for rearrangement and the source of hydrogen for the reaction. This study developed an efficient catalyst for the catalytic hydrogenation and ring rearrangement of FAL into CPO.

The Effect of Composition and Temperature on the Hydrogen Reduction Behavior of Sintered Pellets of Bauxite Residue-Lime Mixtures

This study explores the isothermal hydrogen reduction of sintered pellets made of a mixture of bauxite residue and calcite with varying compositions at different reduction temperatures. Sintered pellets with varying compositions show three primary iron-containing oxide phases including brownmillerite, srebrodolskite, and fayalite; however, brownmillerite is the major phase in all the sintered pellets. The sintered pellets were reduced in a thermogravimetry furnace to establish instantaneous weight reduction with respect to time. Phases and microstructural analysis were carried out using X-ray diffraction and scanning electron microscopy, respectively. Mercury intrusion porosimeter and pycnometer were utilized to assess the porosity and density of the reduced pellets. Thermochemistry calculations were performed using the thermodynamics software FactSage 8.2. The reduction rate is most pronounced at a temperature of 1000 °C for all pellet compositions. It is intriguing to note that the rate of reduction shows minimal variance across pellets with different compositions; however, the higher calcite pellets exhibit a higher initial rate of reduction. Various kinetic models were examined to determine the activation energies for three different composition pellets, and the three-dimensional diffusion model has been well suited for this process. Close activation energies in the range of 84.6 to 94.8 kJ were obtained. A slightly higher activation energy was obtained for lower CaCO3 added pellets, and it was attributed to their reduced porosity and increased sintering, impeding the reaction kinetics. There were no significant differences in the formation of mayenite with varying the calcite amount; however, higher calcite pellets indicated more mayenite formation.Graphical

Methane–Hydrogen-Based Pre-reduction Chromite: Reduction Behavior and Pellet Compressive Strength

Methane–Hydrogen-Based Pre-reduction Chromite: Reduction Behavior and Pellet Compressive Strength

Enhancing effect of Mn2+ substitution in CuAl2O4 spinel for methanol steam reforming in a microreactor

Hydrogen generation via methanol steam reforming is a promising method for producing renewable energy. In this work, a series of Mn2+-substituted CuAl2O4 spinels were prepared by solution combustion method, and the crystal structure, micromorphology, chemical constitution, reduction behavior, acidity, specific surface area and surface chemical state of the spinels were comprehensively characterized by various equipments. The obtained spinels were washcoated on Cu foams to prepare monolithic catalysts, and the catalytic performance of the catalysts was evaluated in a methanol steam reforming microreactor. Compared with the binary Cu–Al spinel, the Mn2+ substitution led to a decrease in the particle size, a change in the chemical composition and reduction behavior, a decline in the acidity, an increase in the specific surface area, and an improvement in the surface chemical state. As a result, the release rate of active Cu from the Mn-containing CuAl2O4 spinel was significantly slowed down and the formed nanoparticles were fine, which was believed to be in favor of maintaining a stable catalytic performance longer. Among the prepared catalysts, the monolithic catalyst loaded with Cu0.4Mn0.6Al2O4 exhibited the highest activity and stability. The findings of this work suggested that introducing Mn2+ might be a promising way to regulate the Cu releasing property for obtaining a better sustained release catalyst system.

Reduction behaviour of electric arc furnace dust (EAFD)-bituminous coal composite pellet in tube furnace

Reduction behaviour of electric arc furnace dust (EAFD)-bituminous coal composite pellet in tube furnace

Effects of B-site Co3+ doping on physicochemical characteristics and hydrogen production performance of novel LaCuxCo1-xO3 perovskite coated on monolithic catalyst in methanol steam reforming

A series of B-site Co3+-doped LaCuxCo1-xO3 (x = 1, 0.8, 0.6, 0.4, 0.2) perovskites were synthesized by solution combustion method and their physicochemical properties were comprehensively characterized. The perovskite-coated Cu foams were applied as monolithic catalysts for methanol steam reforming to produce H2. Results showed that an appropriate amount of Co3+ doping led to the stabilization of crystal structure, the reduction of particle size, the improvement of chemical constitution, the enhancement of reduction behavior, the decrease of acidity, the increase of specific surface area, and the optimization of surface chemical state. The monolithic catalyst loaded with LaCu0.4Co0.6O3 showed the highest methanol conversion rate and H2 production rate, the lowest CO selectivity, the best stability and the lowest carbon deposition. However, excess Co3+ resulted in a degradation of the catalytic performance. The findings of this work suggested that introducing Co3+ might be a promising way to enhance the activity of Cu species for obtaining a better Cu-containing perovskite-based monolithic catalyst.

Multidomain Dementia Risk Reduction in Primary Care is Feasible: A Proof-of-concept study.

Dementia risk reduction is a public health priority, but interventions that can be easily implemented in routine care are scarce. To evaluate the feasibility of integrating dementia risk reduction in regular consultations in primary care and the added value of a dedicated smartphone app ('MyBraincoach'). 188 participants (40-60 years), with modifiable dementia risk factors were included from ten Dutch general practices in a cluster-randomized trial (NL9773, 06/10/2021). Practices were randomly allocated (1 : 1) to provide a risk-reduction consultation only or to additionally provide the app. During the consultation, participants learned about dementia risk reduction and how to improve their risk profile. The app group received daily microteaching-notifications about their personally relevant risk factors. Feasibility was evaluated after 3 months using questionnaires assessing knowledge on dementia risk reduction and health behavior change. The primary outcome was change in the validated "LIfestyle for BRAin health" (LIBRA) score. In-depth interviews were conducted with participants and primary care providers (PCPs). The interventions were positively perceived, with 72.0% finding the consultation informative and 69.2% considering the app useful. Drop-out was low (6.9%). LIBRA improved similarly in both groups, as did Mediterranean diet adherence and body mass index. Knowledge of dementia risk reduction increased, but more in the app group. Interviews provided insight in participants' and PCPs' needs and wishes. Integrating dementia risk reduction in primary care, supported by a smartphone app, is a viable approach towards dementia risk reduction. Larger trials are needed to establish (cost-)effectiveness.

Structural Characterization and Electrochemical Studies of Selected Alkaloid N-Oxides.

In this work, we synthesized and confirmed the structure of several alkaloid N-oxides using mass spectrometry and Fourier-transform infrared spectroscopy. We also investigated their reduction mechanisms using voltammetry. For the first time, we obtained alkaloid N-oxides using an oxidation reaction with potassium peroxymonosulfate as an oxidant. The structure was established based on the obtained fragmentation mass spectra recorded by LC-Q-ToF-MS. In the FT-IR spectra of the alkaloid N-oxides, characteristic signals of N-O group vibrations were recorded (bands in the range of 928 cm⁻1 to 971 cm⁻1), confirming the presence of this functional group. Electrochemical reduction studies demonstrated the reduction of alkaloid N-oxides at mercury-based electrodes back to the original form of the alkaloid. For the first time, the products of the electrochemical reduction of alkaloid N-oxides were detected by mass spectrometry. The findings provide insights into the structural characteristics and reduction behaviors of alkaloid N-oxides, offering implications for pharmacological and biochemical applications. This research contributes to a better understanding of alkaloid metabolism and degradation processes, with potential implications for drug development and environmental science.

Citizens’ pro-environmental behaviors for waste reduction using an extended theory of planned behavior in Guayas province

This study looks at pro-environmental behaviors (PEBs) for waste reduction in Ecuador's heavily populated Guayas area. The research, which focuses on green consumer, recycler, and waste-preventer behaviors, applying an Extended Theory of Planned Behavior (TPB) to investigate the influence of attitudes, subjective norms, and perceived behavioral control on people's intentions to behave environmentally and uses external influences as moderating role variable. This research intends to contribute to targeted treatments and strategies promoting sustainable behaviors and environmental consciousness by better understanding the factors that drive waste reduction PEBs. A total of 3805 people were polled, and confirmatory analysis and structural equation modeling was utilized to review the data. The study finds that attitudes, perceived behavioral control, and subjective norms significantly influence citizens' intentions to engage in green consumer and waste-preventer behaviors. However, the intention to behave ecologically does not significantly affect recycler behavior. External influences also moderate the relationship between intentions and all three-waste reduction pro-environmental behaviors. This investigation illuminates the psychological dimensions underlying the observed variability in pro-environmental waste reduction behaviors among residents in a metropolitan area situated in South America, specifically within a developing world context. Finally, the study emphasizes the importance of addressing citizens' attitudes and norms to promote green consumerism, waste prevention, and recycling. Limitations include self-report bias and demographic bias. Future research should expand to include other regions and countries.

Bioinspired Zwitterionic Nanowires with Simultaneous Biofouling Reduction and Release.

Marine biofouling is a complex and dynamic process that significantly increases the carbon emissions from the maritime industry by increasing drag losses. However, there are no existing non-toxic marine paints that can achieve both effective fouling reduction and efficient fouling release. Inspired by antifouling strategies in nature, herein, a superoleophobic zwitterionic nanowire coating with a nanostructured hydration layer is introduced, which exhibits simultaneous fouling reduction and release performance. The zwitterionic nanowires demonstrate >25% improvement in fouling reduction compared to state-of-the-art antifouling nanostructures, and four times higher fouling-release compared to conventional zwitterionic coatings. Fouling release is successfully achieved under a wall shear force that is four orders of magnitude lower than regular water jet cleaning. The mechanism of this simultaneous fouling reduction and release behavior is explored, and it is found that a combination of 1) a mechanical biocidal effect from the nanowire geometry, and 2) low interfacial adhesion resulting from the nanostructured hydration layer, are the major contributing factors. These findings provide insights into the design of nanostructured coatings with simultaneous fouling reduction and release. The newly established synthesis procedure for the zwitterionic nanowires opens new pathways for implementation as antifouling coatings in the maritime industry and biomedical devices.

Development and validation of a scale to measure hypertensive Chinese individual’s behavior toward salt reduction consumption

ObjectiveThis study aimed to develop and validate the Salt Reduction Behavior Scale (SRBS) to measure the behavior of hypertensive Chinese individuals in adhering to salt reduction practices.MethodsThe SRBS was constructed based on the Health Belief Model, consisting of five constructs: knowledge, perceived severity, perceived benefits, perceived barriers, and cues to action. Data were collected from 2,082 hypertensive patients in Beijing, China, who completed a questionnaire administered through an online platform. Kaiser-Meyer-Olkin (KMO) test was used to assess the adequacy of the sample and the Bartlett’s test of sphericity to examine the factorability of the dataset. Confirmatory Factor Analysis (CFA) was used to assess the structural validity and reliability of the SRBS.ResultsThe KMO analysis yielded a notably elevated value of 0.95, indicating that the data was highly suitable for Exploratory Factor Analysis (EFA). Bartlett’s test of sphericity yielded a statistically significant test statistic (P < 0.001). The 32-item SRB questionnaire demonstrated strong internal consistency with a Cronbach’s alpha coefficient of 0.923. A second-order Confirmatory Factor Analysis (CFA) revealed that, after removing the unrelated construct of barriers, SRB could be represented by four sub-constructs: knowledge, severity, benefits, and action. The final version of the SRBS consists of 21 items. These items displayed high factor loadings, indicating a strong relationship between the items and their respective sub-constructs. The discriminant validity analysis revealed that the SRBS sub-constructs were distinct from each other. The SRBS scores were positively correlated with self-reported salt reduction practices. This demonstrates that individuals with higher SRBS scores were more likely to engage in actual salt reduction behaviors, indicating concurrent validity.ConclusionThe results illustrate that the Salt Reduction Behavior Scale is a robust and comprehensive instrument for assessing salt reduction behavior among hypertensive Chinese individuals. The scale’s specific sub-constructs provide a detailed understanding of their knowledge, attitudes, and practices related to salt consumption. Healthcare professionals and policymakers can utilize this tool to tailor interventions and educational programs to encourage healthier dietary habits, thereby reducing the risk of cardiovascular diseases in China.

Perceived risk and risk reduction behaviors in fish and seafood consumption

This study aimed to explore what risk factors consumers perceive when consuming fish and seafood at a time when treated wastewater was being discharged. Moreover, this study attempted to examine what risk reduction behaviors consumers take to minimize these risk factors. The data was collected online for one week in September 2023 and 334 responses from Korean consumers were used for the analysis. Five risk dimensions were identified: biochemical risk, hygiene risk, environmental risk, value risk, and socio-phycological risk were identified. Higher levels of perceived risks were identified in female respondents and four dimensions of risk (except hygiene risk) showed a significant relationship with risk reduction behavior. Such risk reduction behavior significantly influenced the intention to consume seafood. Practical and theoretical implications were also suggested from the findings of this study.

Does having a family member with dementia affect health beliefs about changing lifestyle and health behaviour for dementia risk reduction?

Dementia is a worldwide public health concern. Implementing lifestyle changes that target modifiable risk factors is crucial for reducing the risk of dementia. The aim of this study was to investigate the effect of having family members with dementia on individuals' health beliefs and tendencies towards adopting healthier lifestyles and behaviours. A cross-sectional, comparative study was conducted with 338 people aged 40 years and older, of whom 168 have the experience of having family members with dementia, and 170 have no such experience. Data were collected using a characteristics form, the Motivation to Change Lifestyle and Health Behaviours for Dementia Risk Reduction scale, and the modified Charlson comorbidity index. Descriptive statistics, Pearson's chi-square and independent t-tests, were used. Those with family members with dementia were more likely to have greater motivation to modify their lifestyle (perceived susceptibility, severity, benefits, and cues to action) to reduce their risk of developing dementia. Additionally, they had greater perceived barriers to gain by adopting a healthy lifestyle, in contrast to those without such family members. The presence of family members with dementia could be an important factor to consider when designing initiatives targeting health beliefs related to dementia prevention behaviours and lifestyle changes.