Physicochemical Actions Research Articles

Synergistic effects of recycled demolition waste and GGBS-FA based geopolymers on the mechanical properties and stabilization mechanism of high plasticity clay

Recycled demolition waste (RDW) and ground granulated blast furnace slag-fly ash-based geopolymer (GFG) are promising materials for treating high-plasticity clay (CH) in highway subgrades. However, the underlying synergistic stabilization mechanisms remain unclear. To elucidate the fundamental mechanisms governing post-treatment soil stabilization, a multi-scale laboratory investigation was undertaken. This investigation encompassed the evaluation of mechanical properties (compaction, California bearing ratio (CBR), and unconfined compressive strength (UCS)) to quantify the enhanced performance of the treated soil. Additionally, microstructural and mineralogical characterization was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and atomic force microscopy (AFM) to elucidate the microscopic mechanisms responsible for this improvement. The results indicated that the addition of RDW led to a reduction in the optimum moisture content (OMC) while increasing the maximum dry density (MDD) of CH. Moreover, upon incorporating RDW-GFG, the mechanical properties of the cured soil exhibited significant improvement. Specifically, the addition of 25% RDW to CH resulted in a 184% increase in CBR and effective improvement in water stability (immersion swelling percentage is reduced). Furthermore, when 25% RDW and 15% GFG were added to CH, the UCS has increased significantly by 8 times. The addition of RDW effectively enhanced the particle size distribution, compacted the soil, thus increased the shear strength. The results from XRD and SEM analyses revealed that the inclusion of GFG could generate geopolymer cementitious bonding network in the soil matrix. These materials facilitated bonding between CH particles and RDW, filling the pores and densifying the overall structure, thus increasing its strength. The synergy of RDW-GFG substantially improved the highly plastic soil through physicochemical actions, markedly elevating both its strength and water stability. Consequently, the outcomes of this experimental study offer valuable insights for road engineering applications.

Adsorption of antibiotics on microplastics (MPs) in aqueous environments: The impacts of aging and biofilms

Microplastics (MPs) that accumulate in natural water bodies through various pathways inevitably undergo aging and biofilm attachment. These variations can alter the physicochemical properties of the MPs and thus affect their abilities to adsorb other pollutants. In this study, we chose virgin polyethylene (V-PE) as the experimental MP and generated aged, biofilm-developed and biofilm-developed with aged polyethylene (A-PE, B-PE and B-A-PE) via Fenton advanced oxidation and lake water incubation methods. Then, the adsorption of tetracycline hydrochloride (TC-HCl) and cefalexin (CFX) on V-PE, A-PE, B-PE and B-A-PE was investigated. The results showed that the capacities for adsorption of TC-HCl or CFX on the four polyethylene MPs (PEMPs) increased in the order V-PE < A-PE < B-PE < B-A-PE. The order was attributed to differences in the surface roughnesses, crystallinities, surface functional groups and biofilm biomass of the four PEMPs. Kinetic experiments and isotherms indicated that nonlinear multilayer adsorption occurred via physicochemical actions, such as diffusion, hydrophobic interactions, hydrogen bonding interactions, electrostatic interactions and biodegradation. Specifically, the adsorption of TC-HCl or CFX by V-PE and A-PE was predominantly controlled by diffusion, whereas B-PE and B-A-PE were chemically active. In addition, it is worth noting that biofilms may shield antibiotics from electrostatic interactions with the B-PE and B-A-PE surfaces, and an increase in ionic strength inhibited the adsorption of TC-HCl and CFX by the four PEMPs. Our study provides an important reference for determining the adsorption of antibiotics by MPs in natural waters.

Treatment of wastewater containing thallium(I) by long-term operated manganese sand filter: Synergistic action of MnOx and MnOM

The long-term and stable removal of thallium (Tl) from industrial wastewater generated by mining and smelting operations remains challenging. While sand filters are commonly applied for the simultaneous removal of Mn(II) and other heavy metals, they have limited efficacy in treating Tl-contaminated wastewater. To address this gap, we operated a lab-scale Mn sand filter (MF) without added microorganisms to investigate the efficiency and mechanisms of Mn(II) and Tl(I) removal. Trends in effluent Mn(II) and Tl(I) concentrations indicated three operational stages: start-up, developing and maturation. Over time, the removal efficiency of Tl(I) gradually improved, plateauing at approximately 80 % eventually. Throughout operation, Tl(I) was sequestrated via surface complexation and ion exchange. Besides, enrichment of Sphingobium and other typical manganese oxidizing microorganisms (MnOM) during operation facilitated Mn(II) and Tl(I) oxidation and sequestration by generating biogenic manganese oxides (BioMnOx). Additionally, the accurate control of water quality and operating conditions during operation could also enhance removal efficiency. In summary, physicochemical actions of Mn oxides and biochemical actions of microorganisms synergistically contributed to the sequestration of Mn(II) and Tl(I). These findings provided a novel and sustainable method for the long-term and stable treatment of industrial wastewater containing thallium.

Assessment of Various Iron Extraction Treatments on Waterlogged Archaeological Oak

Treatments of organic objects to extract ferrous compounds from waterlogged archaeological wood are well documented. For several years, numerous laboratories have been seeking to determine suitable conservation treatments for such organic objects. For chemical treatments, complexing agents such as EDTA and DTPA, along with acids such as citric and oxalic acids, were selected. In addition, oxidants and reducing agents were tested as pre-treatments to improve extraction rates. In fact, chemicals produce a selective reaction on ferrous compounds, which may improve or be inhibited by complexation or dissolution reactions. Their action depends on the type of compound to be extracted and those present inside the wood. The objective of this study was to make a comparative assessment of the various chemical conservation treatments identified and complement the evaluation of their extraction efficiency with a study of their impact on organic matter by adding criteria such as their visual aspect (using a spectrocolorimeter) and physicochemical actions by means of infrared spectroscopy and micromorphological observations. The effectiveness of EDTA was confirmed, as was that of citric acid, despite some questions arising concerning the presence of wood fibers in the treatment solution, even after rinsing. On the other hand, the extraction rate of oxalic acid, which has a very acidic pH, was unsurprisingly lower, but its visual and anatomical results raised the possibility of using it over a short period of time in view of the effectiveness observed on the wood surface. Pre-treatments improved extraction rates, except in the case of EDTA, which independently had a high extraction rate. It was observed that pre-treatments did not appear to cause any significant chemical degradation of the organic matter. This study provides a tool to assist conservators in selecting a chemical treatment that is in line with the state of decay of the wood, the characteristics of the ferrous compounds to be extracted, and the conservation objectives.

Bone matrix quality in paired iliac bone biopsies from postmenopausal women treated for 12months with strontium ranelate or alendronate.

Bone quality is altered mainly by osteoporosis, which is treated with modulators of bone quality. Knowledge of their mechanisms of action is crucial to understand their effects on bone quality. The goal of our study was to compare the action of alendronate (ALN) and strontium ranelate (SrRan) on the determinants of bone quality. The investigation was performed on over 60 paired human iliac biopsies. Paired samples correspond to biopsies obtained from the same patient, one before treatment (baseline) and one after 12months of treatment, in postmenopausal women with osteoporosis. Vibrational spectroscopy (Raman and FTIRM) and nanoindentation were used to evaluate the effect of both drugs on bone quality at the ultrastructural level. Outcomes measured by vibrational spectroscopy and nanoindentation are sensitive to bone age. New bone packets are distinguished from old bone packets. Thus, the effect of bone age is distinguished from the treatment effect. Both drugs modify the mineral and organic composition in new and old bone in different fashions after 12months of administration. The new bone formed during ALN administration is characterized by an increased mineral content, carbonation and apatite crystal size/perfection compared to baseline. Post-translational modifications of collagen are observed through an increase in the hydroxyproline/proline ratio in new bone. The proteoglycan content is also increased in new bone. SrRan directly modulates bone quality through its physicochemical actions, independent of an effect on bone remodeling. Strontium cations are captured by the hydrated layer of the mineral matrix. The mineral matrix formed during SrRan administration has a lower carbonate content and crystallinity after 12months than at baseline. Strontium might create bonds (crosslinks) with collagen and noncollagenous proteins in new and old bone. The nanomechanical properties of bone were not modified with either ALN or SrRan, probably due to the short duration of administration. Our results show that ALN and SrRan have differential effects on bone quality in relation to their mechanism of action.

Enriched Catalytic Activity of TiO2 Nanoparticles Supported by Activated Carbon for Noxious Pollutant Elimination.

Cleaning wastewater has become one of the most serious issues for a number of scientists and researchers in recent years, as water is the most basic need for the daily life of humans. There has been a focus on the removal of noxious pollutants from wastewater effluents by using nanocatalysts owing to their unique physicochemical actions and stability. Herein we manufactured TiO2 nanoparticles supported by activated carbon (AC-TiO2) using a cost-effective sonochemical method. The band structures of the AC-TiO2 and TiO2 were modified from 3.2 to 3.1 eV, thus increasing the catalytic activity. The structural, optical and anatase crystal phase properties, with morphological confirmation, were studied by applying UV-DRS, PL, FESEM, XRD, along with HRTEM, respectively. The specific surface area, calculated by BET analysis, was found to be ~241 m2/gm and ~46 m2/gm for AC-TiO2 and TiO2. The degradation efficiency of the as-prepared nanocatalysts against the very toxic but rarely studied organic textile dye pollutant RO 84 was investigated and 97% efficiency were found for the AC-TiO2 as compared to pure TiO2, which is a highly appreciated finding in the catalytic dye degradation application domain. Such surface-modified nanocatalysts could be further implemented for the treatment of wastewaters/waste effluents released from chemical industries, laboratories and other sources.

Study on the Performance of Primary Means of Measurement of the Hydrogen Concentration During Severe Accidents at NPP

This work is devoted to hydrogen safety security during severe accidents at NPP as well as the validation of equipment performance of passive safety systems under these conditions. The results of an experimental investigation of the performance of the primary means of measurement module of the hydrogen concentration control system under physicochemical actions on them due to the precipitation of insoluble aerosols, non-condensable gases, and oil vapor during severe accidents at NPP are presented. It is shown that the physicochemical actions do not significantly affect the performance of the primary means of measurement module of the hydrogen concentration control system.

Solvent-free ionic nanofluids based on graphene oxide-silica hybrid as high-performance lubricating additive

Solvent-free ionic nanofluids (NFs) of graphene oxide-silica hybrid nanocores (GO@SiO2) were synthesized for the first time via functionalizing in succession the nanocores with a covalently charged corona and an ionically tethered oligomeric canopy. Being intrinsically one-component materials, GO@SiO2 NFs display a liquid-like behavior in the absence of any solvent and show excellent dispersion stability in polyethylene glycol (PEG) base oil. Adding even small amount of GO@SiO2 NFs improved dramatically the lubrication performance of PEG base oil. It was revealed that GO@SiO2 NFs played an important role in physicochemical actions on the friction interface. This work provided direct evidence that a protective tribofilm grew on the sliding surfaces when molecular species of GO@SiO2 NFs were fed continuously onto the contact zone. In particular, graphitized GO and SiO2 nanoparticles digested in the tribofilm enhanced its lubricity and robustness. It is expected that solvent-free ionic GO@SiO2 NFs open up new opportunities for developing advanced lubricating nanomaterials.

Mechanical and physicochemical contribution in removal of different soil types on cotton fabric

The research was conducted to identify the optimal washing methods for three types of soils, in terms of washing efficiency and eco-efficiency. To this end, the mechanical action by the washer’s agitation and the physicochemical action by detergents were investigated for their respective contribution to the detergency of three kinds of artificial soils: oil, protein, and their mixture. In general, washing efficiency increased with the increased agitation speed and the amount of detergent use. Most of the washing conditions presented a positive synergistic effect when both the mechanical and physicochemical actions were applied simultaneously. The contributing ratio of the physicochemical action was greater for oily soil than for other soil types, due to the effective rolling-up by the detergent for the oily soil. The contributing ratio attributable to the mechanical action was higher when the protein was present in the soil composition, and the mechanical contribution was compromised as detergent usage was increased. The washing condition with the largest synergy did not always correspond with the condition of the highest washing efficiency. Energy Efficiency for Detergency was increased in all soil types as the agitation speed increased. It is suggested that the washing method be determined considering (1) the level of soiling and the acceptable washing performance, (2) the synergistic effect of mechanical and physicochemical actions, and (3) the eco-efficiency of washing methods.

Contributing ratio of the mechanical and the physicochemical actions to washing efficiency of mineral oil and protein soils

It was attempted to separate the detergency contributions from the mechanical actions and the physicochemical actions for two different types of soils. The mechanical washing efficiency was evaluated through the washing performed under the mechanical agitation, in the absence of detergent. The physicochemical washing efficiency was examined in the washing bath with detergent in the absence of mechanical agitation. Among the washing parameters, extended washing time and higher washing temperature were effective improving the mechanical and physicochemical washing efficiencies for mineral oil and carbon black. For blood soil, lower washing temperature and extended washing time enhanced the mechanical and physicochemical washing efficiencies. For the mineral oil, the presence of both mechanical and physicochemical actions led to the effective washing performance with synergistic effect. For the blood soil, mechanical actions were observed as more contributing than the physicochemical actions. The optimized washing program could be recommended as per the contributing ratios for the specific soil types, minimizing the energy consumption and detergent usage while achieving the washing performance.

Non-selective distribution of isomeric cholesterol hydroperoxides to microdomains in cell membranes and activation of matrix metalloproteinase activity in a model of dermal cells

Cholesterol hydroperoxides (ChOOHs) are included as lipid peroxidation products in the skin exposed to ultraviolet (UV) light irradiation. They may exert physicochemical actions affecting biomembrane rigidity because cholesterol is one of the major components of cell membranes. We investigated the distribution of isomeric ChOOHs in heterogeneous cell membranes with different lipid profiles using mouse fibroblast NIH-3T3 cells as a model of the dermis. Before and after UVA irradiation in the presence of hematoporphyrin, cell membranes were partitioned to microdomains (lipid rafts and caveolae) containing a higher amount of cholesterol and non-microdomains (containing a lower amount of cholesterol) by ultracentrifugation. By a combination of diphenylpyrenylphosphine-thin-layer chromatography blotting analyses and gas chromatography–electron ionization-mass spectrometry/selected ion monitoring analyses, ChOOH isomers were determined as their trimethylsilyloxyl derivatives. Cholesterol 5α-, 7α- and 7β-hydroperoxide were found as isomeric ChOOHs before irradiation. The amounts of the three ChOOH isomers increased significantly after photoirradiation for 2h. No difference was observed between microdomains and non-microdomains with regard to the ratio of the amounts of isomeric ChOOHs to that of cholesterol, suggesting that these ChOOH isomers were distributed equally in both parts depending on cholesterol content. When cells were treated with a purified mixture of ChOOH isomers, cell membranes incorporated ChOOHs into microdomains as well as non-microdomains evenly. Cellular matrix metalloproteinase-9 (MMP-9) activity was elevated by treatment with the purified mixture of ChOOH isomers. These results strongly suggest that ChOOHs accumulate in cell membranes irrespective of the heterogeneous microstructure and promote MMP activity if dermal cells are exposed to photodynamic actions.

Dynamics of rearrangement of a solid under physicochemical actions

In this study, the interrelation of the phasestruc� tural variations, heat and mass transfer, and ther� moelasticity is taken into account. The equations are derived here from the general laws of mechanics. The solutions allowed studying the processes from impu� rity entry to possible degradation of the elastic proper� ties of a material. The conditions are analyzed under which impurity accumulation causes a folded local σ- e diagram. It is shown, however, that such a shape of the σ-e diagrams does not always imply a phase tran� sition. We will consider an elastic skeleton, for example, a lattice of a metal, and an impurity penetrating from the outside. During diffusion, a part of the impurity is bonded by the skeleton. Since the laws of motion of the bonded impurity and the skeleton coincide, we consider them a unit component 1. Name a moving part of the impurity component 2. We will describe it within the model of an ideal liquid. Both components can be in any vicinity of a point of the solid. Between the neighboring points of different components, the exchange can occur, i.e., embedding in the bond, binding by the skeleton, or release. Coordinates of such points in the continual writing coincide. The equations of motion, mass balance between the components, and thermal conductivity in the component 1 are

Performance Optimization Control of ECH using Fuzzy Inference Application

Electro-chemical honing (ECH) is a hybrid electrolytic precision micro-finishing technology that, by combining physico-chemical actions of electro-chemical machining and conventional honing processes, provides the controlled functional surfaces-generation and fast material removal capabilities in a single operation. Process multi-performance optimization has become vital for utilizing full potential of manufacturing processes to meet the challenging requirements being placed on the surface quality, size, tolerances and production rate of engineering components in this globally competitive scenario. This paper presents an strategy that integrates the Taguchi matrix experimental design, analysis of variances and fuzzy inference system (FIS) to formulate a robust practical multi-performance optimization methodology for complex manufacturing processes like ECH, which involve several control variables. Two methodologies one using a genetic algorithm tuning of FIS (GA-tuned FIS) and another using an adaptive network based fuzzy inference system (ANFIS) have been evaluated for a multi-performance optimization case study of ECH. The actual experimental results confirm their potential for a wide range of machining conditions employed in ECH.

Multi-performance modeling and optimization control strategies for electro-chemical honing: a critical evaluation

Electro-chemical honing (ECH) is a hybrid electrolytic precision micro-finishing technology that integrates physicochemical actions of the electro-chemical machining and conventional honing processes to provide controlled functional surface-generation and fast material removal capabilities in a single operation. Three different strategies, namely the utility-based Taguchi approach, Taguchi–RBFNN–DF–GA strategy and GA-tuned fuzzy Taguchi inference application, have been recently reported by the author for multi-performance modeling and optimization control ECH process. In this work a critical evaluation of their prospective features, strengths and weaknesses has been done for benefit of the user and research fraternity. The methodologies have been demonstrated using a case study of multi-performance modeling and optimization control ECH, involving three performance criteria. Results indicate that all three techniques are well suited to the complex manufacturing processes that involve several correlated variables with vaguely defined parametric relationships like in ECH. It was also found that the predicted optimal results are sensitive to the way the factorial interactions are treated. The actual experimental results at the optimal parametric conditions predicted using the three approaches are quite close.

Chemical and hormonal determinants of vascular calcification in vitro

Vascular calcification is a complex process that is dependent not only on the physicochemical effects of Ca, PO(4), and pH, but also on smooth muscle factors that may be regulated by these ions as well as by 1,25-dihydroxyvitamin D(3) (calcitriol) and parathyroid hormone (PTH). These minerals and hormones were tested in a model of medial calcification in rat aorta maintained in culture for 9 days. Calcification was quantitated as incorporation of (45)Ca, alkaline phosphatase activity was measured in aortic homogenates, and osteopontin production was measured from immunoblots of culture medium. At 1.8 mM Ca (1.46 mM free), calcification occurred at or above 2.8 mM PO(4). At 3.8 mM PO(4), calcification occurred at or above 1.10 mM free [Ca]. At a constant [Ca] x [PO(4)], calcification varied directly with [Ca] and inversely with [PO(4)]. Calcification was directly related to pH between 7.19 and 7.50 but not altered by PTH or calcitriol. Alkaline phosphatase activity and osteopontin production were increased by Ca, PO(4), calcitriol, and PTH. We conclude that calcification of rat aorta in vitro requires elevation of both [Ca] and [PO(4)], and that [Ca] rather than [PO(4)] or the product of the two is the dominant determinant. The induction of alkaline phosphatase and osteopontin indicates that Ca and PO(4) have effects in addition to simple physicochemical actions. Although PTH and calcitriol did not increase calcification in vivo, they have effects on smooth muscle that could influence calcification in vivo. Calcification is enhanced by alkalinity within the range produced during hemodialysis.

The Type I Membrane Protein EFF-1 Is Essential for Developmental Cell Fusion

Multinucleate cells are widespread in nature, yet the mechanism by which cells fuse their plasma membranes is poorly understood. To identify animal fusogens, we performed new screens for mutations that abolish cell fusion within tissues of C. elegans throughout development. We identified the gene eff-1, which is expressed as cells acquire fusion competence and encodes a novel integral membrane protein. EFF-1 sequence motifs suggest physicochemical actions that could cause adjacent bilayers to fuse. Mutations in the extracellular domain of EFF-1 completely block epithelial cell membrane fusion without affecting other prefusion events such as cell generation, patterning, differentiation, and adhesion. Thus, EFF-1 is a key component in the mechanism of cell fusion, a process essential to normal animal development.

乾式化学的微粒子化促進法による粘土鉱物セリサイトの微粒子化 硝酸塩類の粉砕性に及ぼす影響

Chemically assisted comminution, in which chemical and/or physicochemical actions are introduced into powders to be ground, was conducted under dry conditions. The comminution method is called “chemically assisted dry comminution” (CADC). In the CADC sericite powder, a kind of mica, was first mixed with a nitrate, and the mixed powder was comminuted under a dry condition, followed by obtaining finely ground sericite after removing the nitrate by water cleaning. Lithium, sodium, potassium and rubdium nitrate were used as the nitrates.The sericite powder obtained by every CADC had a much larger specific surface area and a smaller amount of impurity than that obtained by an ordinary dry comminution. On the other hand, the median diameters of sericite by CADC were slightly smaller than those by an ordinary dry comminution.Potassium ions in sericite decreased only in the case of the CADC, which suggested that potassium ions were exchanged with alkali ions in the nitrate during the CADC. There was a correlation between the amount of exchanged potassium ions and the specific surface area of the sericite by the CADC. Stabilisation of the nascent surface and the prevention of agglomeration of the sericite by nitrate during comminution was considered to be another reason for the enhanced grindability by CADC.

Mitigation of problem clouds

Abstract This paper describes the use of fluid curtains for the mitigation of problem clouds. Mechanical and physico-chemical actions of spray barriers are examined. Practical engineering codes are developed with the support of experimental findings gathered on dedicated facilities. It is shown that forced dispersion is more appropriate for the dilution of flammable gases, while the efficient dispersion of a toxic dense pollutant requires the use of inhibiting liquid curtains. The design rules of these two types of spray curtains exhibit important differences. Mechanical curtains require coarse upward sprays in combination with a small upstream fence. Physico-chemical absorbing barriers rely on fine sprays; therefore, additional studies of wind effect are needed. The concept of the dual diluting/inhibiting curtain is suggested for future investigation.

Effect of Meal on the Physiological and Physicochemical Actions of Potassium Citrate

The effect of meals on the physiological and physicochemical actions of potassium citrate was examined in 8 patients with nephrolithiasis maintained on a constant metabolic dietary regimen. Potassium citrate (20mEq. 3 times per day), whether given with food or on an empty stomach, significantly increased urinary pH, citrate and potassium, and decreased urinary calcium and ammonium. Moreover, potassium citrate decreased urinary saturation of calcium oxalate and uric acid, although it slightly increased that of brushite. However, there was no significant difference in these measures when the drug was given with meals from the time when it was given on an empty stomach. Thus, the effect of potassium citrate on urinary risk factors is unaffected by food.

Occurrence and determination of a herbicide benthiocarb in rivers and agricultural drainages

The occurrence and determination of a herbicide, benthiocarb, 4-chlorobenzyl N, N-diethylthiolcarbamate (Saturn ®) in rivers and agricultural drainages was investigated. Benthiocarb residues were detected in water samples when it has been applied to rice paddies, after rice seedling transplantation, in concentrations of between 10.00 and 0.11 μg/l. These residues entered into rivers and agricultural drainages as a result of overflows from rice paddies. However, benthiocarb residues could not be found in water samples after the termination of its application to rice paddies, suggesting that the applied benthiocarb might be degraded by microbial and physico-chemical actions such as photochemical reactions occurring on the soil surface. Benthiocarb residue levels were higher in longer rivers than in agricultural drainage. The contribution of rainfall to the benthiocarb concentrations was shown. Benthiocarb in water was extracted with n-hexane and identified by a gas chromatography using a flame photometric detector (sulphur filter 394 nm) and a combined gas chromatography-mass spectrometry-computer system. The minimum detectable amount of benthiocarb in water sample by gas chromatography was 0.56 ng and about 100 ng of benthiocarb could be identified by a gas chromatography-mass spectrometry-computer system.