Trace Additives Research Articles

Effect of anionic polyacrylamide amendment on the climatic durability of solidified waste rock fine

In order to improve the climatic durability of solidified waste rock fine (WRF), anionic polyacrylamide (APAM) was innovatively introduced to amend solidified WRF in this study. The effects of APAM content, freeze-thaw (F-T), and wet-dry (W-D) cycles on the mechanical behaviors of solidified WRF were explored. After that, zeta potential, fourier transform infrared (FTIR) spectroscopy, and scanning electron microscope (SEM) tests were initiated to understand the behavioral mechanisms of APAM. The results show that APAM can significantly improve the mechanical properties and durability of solidified WRF, and there exist a threshold content of APAM (0.3%~0.8% in this study), beyond which the strength will decrease. The microscopic test shows that the bridging effect and the filming effect induced by APAM are considered to be the two decisive factors affecting the mechanical behavior of S-WRF. On the one hand, the linear APAM long chain enables the cohesion between particles to be stronger through ion bridging, on the other hand, the long chains cross-link with each other to form a network interwoven inside the structure, thus playing a microfabric reinforcement role and enhancing the crack resistance of the solidified matrix. In addition, life cycle assessment (LCA) further confirmed the advantages of using industrial by-products combined with APAM to amend solidified-WRF. These results provide a theoretical basis for using APAM as trace additives to mitigate climatic durability-related issues.

Unveiling the Descriptor of Parasitic Reactions of Zinc Anode: A Comparative Study of Trace Pyridinesulfonic Acid‐Based Additives in Aqueous Electrolyte

AbstractUnderstanding and controlling parasitic reactions on the Zn metal anode (ZMA) surface is essential to enhance the energy capabilities of aqueous zinc‐ion batteries (ZIBs). However, the accurate regulation scheme is often obscured due to the lack of fundamental understanding concerning the ZMA/electrolyte interface. Herein, the descriptor of interfacial parasitic reactions is revealed through a systematic comparative study of three model trace adsorption‐type pyridinesulfonic acid‐based additives with structural variations. Using in situ spectroscopies coupled with density functional theory calculations, direct spectroscopic evidence of interfacial H2O evolution during Zn2+ deposition process is obtained. It is proposed that, beyond the traditional cognitions, the distance between solvated Zn(H2O)62+ and ZMA surface highly dictates the stability of ZMAs. Consequently, the trace 3‐Pyridinesulfonic acid with most effective capacity to drive solvated Zn(H2O)62+ away from the ZMA surface, enables a robust cycle life over 420 h for the Zn||Zn symmetric cell at 10 mA cm−2/10 mAh cm−2 (depth of discharge of 45%), a high Coulombic efficiency of 99.78% and an extended cycling life of 1500 cycles for the Zn//NH4V4O10 full battery. The work sheds light on the underlying mechanism of parasitic reactions on ZMA surface and provides fundamental insights into the design of trace additives for better ZIBs.

Direct Observation of Trace Elements in Barium Titanate of Multilayer Ceramic Capacitors Using Atom Probe Tomography.

Accurately controlling trace additives in dielectric barium titanate (BaTiO3) layers is important for optimizing the performance of multilayer ceramic capacitors (MLCCs). However, characterizing the spatial distribution and local concentration of the additives, which strongly influence the MLCC performance, poses a significant challenge. Atom probe tomography (APT) is an ideal technique for obtaining this information, but the extremely low electrical conductivity and piezoelectricity of BaTiO3 render its analysis with existing sample preparation approaches difficult. In this study, we developed a new APT sample preparation method involving W coating and heat treatment to investigate the trace additives in the BaTiO3 layer of MLCCs. This method enables determination of the local concentration and distribution of all trace elements in the BaTiO3 layer, including additives and undesired impurities. The developed method is expected to pave the way for the further optimization and advancement of MLCC technology.

Cation Chain Length of Nonhalogenated Ionic Liquids Matters in Enhancing SERS of Cytochrome c on Zr-Al-Co-O Nanotube Arrays.

Surface-enhanced Raman scattering (SERS) is a remarkably powerful analytical technique enabling trace-level detection of biological molecules. The interaction of a probe molecule with the SERS substrate shows important distinctions in the SERS spectra, providing inherent fingerprint information on the probe molecule. Herein, nonhalogenated phosphonium-based ionic liquids (ILs) containing cations with varying chain lengths were used as trace additives to amplify the interaction between the cytochrome c (Cyt c) and Zr-Al-Co-O (ZACO) nanotube arrays, strengthening the SERS signals. An increased enhancement factor (EF) by 2.5-41.2 times compared with the system without ILs was achieved. The improvement of the SERS sensitivity with the introduction of these ILs is strongly dependent on the cation chain length, in which the increasing magnitude of EF is more pronounced in the system with a longer alkyl chain length on the cation. Comparing the interaction forces measured by Cyt c-grafted atomic force microscopy (AFM) probes on ZACO substrates with those predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, the van der Waals forces became increasingly dominant as the chain length of the cations increased, associated with stronger Cyt c-ZACO XDLVO interaction forces. The major contributing component, van der Waals force, stems from the longer cation chains of the IL, which act as a bridge to connect Cyt c and the ZACO substrate, promoting the anchoring of the Cyt c molecules onto the substrate, thereby benefiting SERS enhancement.

Metasurface-based sensor with terahertz molecular fingerprint enhancement in trace additives identification

Terahertz (THz) wave has gained considerable interest in biosensing with its unique spectral fingerprint characteristics. However, limited sensitivity confines its applications in trace-amount identification. In this article, a magnetic dipole metamaterial for strengthening molecular fingerprint in virtue of angle-scanning strategy is proposed, which is carefully designed by elaborately arranging symmetric condition of the dipole structures. The physical mechanism is elucidated by the finite-difference time-domain method. In virtue of manipulating the incident angle, the signal of molecular fingerprint is outstandingly elevated. Consequently, three kinds of food additives including azodicarbonamide, sorbic acid and melamine can be simultaneously detected, and the corresponding identification limits are as low as 1.65 μgcm−2 , 1.20 μgcm−2 and 1.66 μgcm−2 , respectively. Our work offers a new train of thought in identifying trace-amount food additives and paves the way for more practical applications of THz wave in food industry.

Interfacial H2O Structure Matters: Realizing Stable Zinc Anodes with Trace Acesulfame‐K in Aqueous Electrolyte

AbstractThe stability of Zinc metal anodes (ZMAs) significantly limits the electrochemical performance and practical application of aqueous Zn‐ion batteries (ZIBs). An efficient and economical solution is the use of trace additives. However, efforts on trace additives are sparse, and essential uncertainties remain concerning their role in the stabilization of ZMAs. Herein, a low‐cost ZnSO4‐based aqueous electrolyte containing trace amounts of Acesulfame‐K (AK) (only 1.0 mg mL−1) is reported, which effectively suppresses the parasitic reactions occurring on the ZMA surface to realize a dendrite‐free Zn2+ deposition process, an ultra‐long cycle life over 1600 h and a high Coulombic efficiency of 99.86%. Accordingly, the practical Zn//NH4V4O10 full cell with AK also exhibits a high discharge capacity and capacity retention. In situ spectroscopies coupled with theoretical calculations reveal that the trace AK tends to accumulate at the ZMA/electrolyte interface to alleviate electrolyte corrosion. More importantly, the adsorbed AK can regulate the interfacial H2O structures (i.e., disrupting the interfacial H‐bonds to form more isolated H2O) to reduce the proton/hydroxides transport, thus suppressing the parasitic hydrogen evolution reaction and improving low‐temperature acclimation. This study provides design inspiration for trace additives expected to enable low‐cost and practical ZIBs with long lifespans.

Atomic Pinning of Trace Additives Induces Interfacial Solvation for Highly Reversible Zn Metal Anodes.

Aqueous Zn metal batteries are considered promising energy storage devices due to their high energy density and low cost. Unfortunately, such great potential is at present obscured by two clouds called dendrite growth and parasitic reactions. Herein, trace amounts of sodium cyclamate (CYC-Na) are introduced as an electrolyte additive, and accordingly, an atomic-pinning-induced interfacial solvation mechanism is proposed to summarize the effect of trace addition. Specifically, coadsorption of -NH- and -SO3 groups overcomes the ring-flipping effect and pins the CYC anion near the Zn anode surface in parallel, which significantly modifies the Zn2+ solvation sheath at the interface. This process homogenizes the surface Zn2+ flux and reduces the H2O and SO42- content on the surface, thus eliminating byproducts and leveling Zn deposition. Cells with trace CYC-Na cycle stably for 3650 h and still cycle for 330 h at high depths of discharge of 56.9%. This work dispels the clouds for efficient trace additives for AZMBs.

Isolating gasdynamic and chemical effects on the detonation cellular structure: A combined experimental and computational study

The dependence of detonation cell regularity on mixture gasdynamic and chemical kinetic properties are investigated through hydrogen-oxygen detonations with different diluent and ozone addition. A total of seven mixtures are specifically designed such that the post-shock specific heat ratio γVN, representing the gasdynamic effect, and the effective activation energy ϵi, representing the chemistry effect, can be varied independently among these mixtures. Both experiments and two-dimensional (2D) Navier-Stokes simulations are performed. For the ranges of γVN and ϵi considered, γVN is found to moderately affect cell regularity. For mixtures of relatively large γVN (≥1.3), detonation cells become slightly irregular with decreasing γVN. A clear increase in cell irregularity is found when γVN is small (<1.3). In contrast, the impact of ϵi on cell regularity is more notable: mixtures of large ϵi produce significantly more irregular cells, corresponding to frequent appearances of transverse detonation structures that dominate the global burning behavior. Finally, ozone is qualitatively and quantitatively shown to regulate the detonation structures in both simulations and experiments tested in this study, and results suggest that trace additives that alter the ϵi of a mixture can likely be used to tune the mixture for a desired regularity.

Trace additive enhances microwave dielectric performance significantly to facilitate 5G communications

AbstractThe ZnZrNb2O8 + x wt% LiF, MgF2, CuO (0.00 ≤ x ≤ 0.10), and Zn1−xCuxZrNb2O8 (0.000 ≤ x ≤ 0.050) ceramics were synthesized through solid‐state reaction. Compared with pure ZnZrNb2O8 ceramic, the quality factor and microstructure densification of the specimens with the addition of trace additives were significantly improved. When CuO was utilized as a sintering additive, is mostly impacted by relative density, whereas Q f value is primarily influenced by grain size. When CuO was employed as a dopant, is strongly connected to the dielectric polarizability and lattice vibration, Q f value is driven mostly by chemical bond covalency, and value is primarily dictated by variations in Nb–O bond energy and bond valence. Notably, the ceramics demonstrated excellent characteristics ( = 27.404, Q f = 74 213 GHz, = −52.779 ppm/°C, ZnZrNb2O8 + 0.06 wt% CuO; = 27.448, Q f = 72 520 GHz, = −53.143 ppm/°C,Zn0.997Cu0.003ZrNb2O8), and these make them promising for use in fifth generation communications.

Tailoring Electrolyte Dehydrogenation with Trace Additives: Stabilizing the LiCoO2 Cathode beyond 4.6 V

Extending the charge cutoff voltage of cathode (e.g., LiCoO2) is a promising way to increase the energy density of Li-ion batteries, but critical challenges lie in the threats triggered by structural distortion and an unstable electrode/electrolyte interface. The general approach to enhance the stability of the cathode/electrolyte interface (CEI) consists of replacing the decomposition or sacrificing sources of carbonate solvents (e.g., EC) with concentrated or fluorinated electrolyte strategies. Herein, without following typical replacement strategies, we introduce a trace electrolyte additive and refine the dehydrogenation process of the original carbonate solvents, resulting in an enhanced CEI and long-term cycling stability of LiCoO2 up to 4.65 V. We demonstrate that cathode structure distortion, LiPF6 hydrolysis, and Co dissolution and shuttling have been simultaneously restrained. With the achievement of a long-life 250 and 270 Wh/kg pouch cells (assembled with a commercial graphite and SiO anodes), the refinement of the “old-school” electrolyte additive strategy opens up avenues toward the design of practical high-voltage full-cell systems.

Visualizing Solution Structure at Solid-Liquid Interfaces using Three-Dimensional Fast Force Mapping

Amongst the challenges for a variety of research fields are the visualization of solid-liquid interfaces and understanding how they are affected by the solution conditions such as ion concentrations, pH, ligands, and trace additives, as well as the underlying crystallography and chemistry. In this context, three-dimensional fast force mapping (3D FFM) has emerged as a promising tool for investigating solution structure at interfaces. This capability is based on atomic force microscopy (AFM) and allows the direct visualization of interfacial regions in three spatial dimensions with sub-nanometer resolution. Here we provide a detailed description of the experimental protocol for acquiring 3D FFM data. The main considerations for optimizing the operating parameters depending on the sample and application are discussed. Moreover, the basic methods for data processing and analysis are discussed, including the transformation of the measured instrument observables into tip-sample force maps that can be linked to the local solution structure. Finally, we shed light on some of the outstanding questions related to 3D FFM data interpretation and how this technique can become a central tool in the repertoire of surface science.

Research on Enhanced Detection of Benzoic Acid Additives in Liquid Food Based on Terahertz Metamaterial Devices.

It is very important for human health to supervise the use of food additives, because excessive use of food additives will cause harm to the human body, especially lead to organ failures and even cancers. Therefore, it is important to realize high-sensibility detection of benzoic acid, a widely used food additive. Based on the theory of electromagnetism, this research attempts to design a terahertz-enhanced metamaterial resonator, using a metamaterial resonator to achieve enhanced detection of benzoic acid additives by using terahertz technology. The absorption peak of the metamaterial resonator is designed to be 1.95 THz, and the effectiveness of the metamaterial resonator is verified. Firstly, the original THz spectra of benzoic acid aqueous solution samples based on metamaterial are collected. Secondly, smoothing, multivariate scattering correction (MSC), and smoothing combined with first derivative (SG + 1 D) methods are used to preprocess the spectra to study the better spectral pretreatment methods. Then, Uninformative Variable Elimination (UVE) and Competitive Adaptive Reweighted Sampling (CARS) are used to explore the optimal terahertz band selection method. Finally, Partial Least Squares (PLS) and Least square support vector machine (LS-SVM) models are established, respectively, to realize the enhanced detection of benzoic acid additives. The LS-SVM model combined with CARS has the best effect, with the correlation coefficient of prediction set (Rp) is 0.9953, the root mean square error of prediction set (RMSEP) is 7.3 × 10−6, and the limit of detection (LOD) is 2.3610 × 10−5 g/mL. The research results lay a foundation for THz spectral analysis of benzoic acid additives, so that THz technology-based detection of benzoic acid additives in food can reach requirements stipulated in the national standard. This research is of great significance for promoting the detection and analysis of trace additives in food, whose results can also serve as a reference to the detection of antibiotic residues, banned additives, and other trace substances.

Hydrated Ionic Liquids Boost the Trace Detection Capacity of Proteins on TiO2 Support.

Trace detection based on surface-enhanced Raman scattering (SERS) has attracted considerable attention, and exploiting efficient strategies to stretch the limit of detection and understanding the mechanisms on molecular level are of utmost importance. In this work, we use ionic liquids (ILs) as trace additives in a protein-TiO2 system, allowing us to obtain an exceptionally low limit of detection down to 10–9 M. The enhancement factors (EFs) were determined to 2.30 × 104, 6.17 × 104, and 1.19 × 105, for the three systems: one without ILs, one with ILs in solutions, and one with ILs immobilized on the TiO2 substrate, respectively, corresponding to the molecular forces of 1.65, 1.32, and 1.16 nN quantified by the atomic force microscopy. The dissociation and following hydration of ILs, occurring in the SERS system, weakened the molecular forces but instead improved the electron transfer ability of ILs, which is the major contribution for the observed excellent detection. The weaker diffusion of the hydrated IL ions immobilized on the TiO2 substrate did provide a considerably greater EF value, compared to the ILs in the solution. This work clearly demonstrates the importance of the hydration of ions, causing an improved electron transfer ability of ILs and leading to an exceptional SERS performance in the field of trace detection. Our results should stimulate further development to use ILs in SERS and related applications in bioanalysis, medical diagnosis, and environmental science.

Capillary Zone Electrophoresis Determination of Five Trace Food Additives in Beverage Samples Using Counterflow Transient Isotachophoresis

Transient isotachophoresis (tITP) is a universal online sample preconcentration technology. It uses ITP to focus electrically charged analytes during the initial stage of capillary electrophoresis (CE) analysis, which can effectively improve the sensitivity of CE. In this work, an approach of tITP under counter-electroosmotic flow was developed for capillary zone electrophoresis (CZE) determination of five trace food additives which include benzoic acid, sorbic acid, sunset yellow, allura red, and amaranth in beverage samples. The parameters that affect the preconcentration effect of the system, such as the type of terminating electrolyte and its injection time, the preconcentration time of ITP, and the sample injection time, have been investigated in detail. The mechanism of counterflow-tITP was explored preliminarily. Under optimal conditions, the sensitivity of five food additives was improved 11.9, 11.5, 13.04, 10.05, and 15.3 times. Their limits of detection (LODs, S/N = 3) reached 0.15, 0.10, 0.38, 0.33, and 0.11 μg/ml, with good repeatability (peak area RSDs ≤ 6.9%) and calibration graph linearity (r ≥ 0.9992). Recoveries of five food additives in spiked beverage samples ranged from 92.0 to 100.8% with RSDs between 1.38 and 2.95%. This method is simple, rapid, and sensitive. It has been successfully applied to the separation and detection of trace food additives in cocktails, orange juice, and carbonated beverages. The feasibility of determination of trace additives in beverages by tITP-CZE under the condition of counterflow has been confirmed.

Light-Induced EPR Study of the Effect of Coumarin Trace Additives on Spin Dynamics in the P3DDT/PC61BM Polymer Composite

The paper presents the results of an EPR study of the magnetic, relaxation, and dynamic parameters of spin charge carriers photogenerated by light in photovoltaic polymer composites, based on poly(3-dodecylthiophene) (P3DDT) and 6,6-phenyl-C61-butyric acid methyl ester (PCBM), in the presence of coumarin admixed to the system. It has been shown that the concentration of polarons and fullerene radical anions is characterized by a nonmonotonic dependence on the energy of incident photons with extrema at 1.9 and 2.7 eV. The largest increase in the concentration of mobile charge carriers was observed in composites with a coumarin content of 3 or 6 wt %. A significant slowdown of the carrier recombination process in the composites containing 3–6 wt % coumarin was observed after switching off the light. The temperature dependences of the concentrations of mobile and localized charge carriers for P3DDT/PCBM samples with a coumarin content of 3 wt % showed enhancement of the exchange interaction between charge carriers. The data obtained lead to the conclusion that coumarin affects spin interactions in the polymer composite.

Autonomous Electrolyte Discovery for Batteries with Experimentally Informed Bayesian Optimization

An autonomous battery electrolyte experimental platform capable of mixing multi-component electrolyte systems and characterizing the transport and electrochemical properties in a high-throughput manner is disclosed. A Bayesian optimization software package found novel electrolyte compositions through optimization of the high-dimensional electrolyte design space over key design objectives like electrochemical stability and conductivity.Electrolyte optimization is difficult because 1) electrolyte evaluation is expensive and takes time, and 2) the space of possible electrolytes is expansive, formed by many possible choices for solvents (often in ternary blends), salts (often in binary mixtures), and trace additives. Bayesian optimization methods are well suited for the optimization of high-dimensional functions with costly evaluations, often producing an efficient design-of-experiments to converge on multi-objective optimal formulations in few experiments. To expedite the optimization over the expansive design space, theoretical predictions of electrolyte properties via the Advanced Electrolyte Model were utilized as “priors” in the statistical model.Implementation of the novel experimental platform was carried out by two novel test stands developed to automate the mixing and characterization of electrolytes: Otto (for aqueous systems) and Clio (for aprotic/organic systems). The test stands characterized the ionic conductivity and electrochemical stability of electrolyte systems, featuring a four-electrode conductivity probe, pH meter, and a flow-through three-electrode cell and potentiostat. Clio also integrated electrochemically active electrodes for optimization of electrolyte/electrode systems. The active electrode systems used were common functional ceramic metal oxides.A software orchestration and data layer linked the test-stands to human experimenters and machine-learning packages through a web-services architecture; all experiment data and meta-data is saved in a database. Additional out-of-the-loop characterization was conducted on cathodic systems to validate composition, structure, and oxidation state.The aqueous design space consisted of aqueous blends of lithium and sodium salts, including nitrates, sulfates, and other commonly-used battery salts. High-concentration aqueous electrolyte candidates were discovered by optimizing of electrochemical voltage stability and conductivity, including low-cost, high-performing alternatives to known but costly aqueous electrolytes (e.g. LiTFSI). Clio’s design space includes blends of both aprotic organic solvents and solutes in additional to various compositions of electrochemically active electrodes. The test-stands are demonstrated to be significantly faster than common human experimentation techniques, converging on novel, optimized electrolyte mixtures in mere hours or days of experimentation.

Organic-Inorganic Nanohybrid Electrochemical Sensors from Multi-Walled Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles and In-Situ Wrapped with Poly(2-methacryloyloxyethyl ferrocenecarboxylate) for Detection of the Content of Food Additives.

An electrochemical sensor for detection of the content of aspartame was developed by modifying a glassy carbon electrode (GCE) with multi-walled carbon nanotubes decorated with zinc oxide nanoparticles and in-situ wrapped with poly(2-methacryloyloxyethyl ferrocenecarboxylate) (MWCNTs@ZnO/PMAEFc). MWCNTs@ZnO/PMAEFc nanohybrids were prepared through reaction of zinc acetate dihydrate with LiOH·H2O, followed by reversible addition-fragmentation chain transfer polymerization of 2-methacryloyloxyethyl ferrocenecarboxylate, and were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), scanning electron microscope (SEM), and transmission electron microscope (TEM) techniques. The electrochemical properties of the prepared nanohybrids with various composition ratios were examined by cyclic voltammetry (CV), and the trace additives in food and/or beverage was detected by using differential pulse voltammetry (DPV). The experimental results indicated that the prepared nanohybrids for fabrication of electrochemical modified electrodes possess active electroresponse, marked redox current, and good electrochemical reversibility, which could be mediated by changing the system formulations. The nanohybrid modified electrode sensors had a good peak current linear dependence on the analyte concentration with a wide detection range and a limit of detection as low as about 1.35 × 10−9 mol L−1, and the amount of aspartame was measured to be 35.36 and 40.20 µM in Coke zero, and Sprite zero, respectively. Therefore, the developed nanohybrids can potentially be used to fabricate novel electrochemical sensors for applications in the detection of beverage and food safety.

Chemical Composition and Toxicity of Particles Emitted from a Consumer-Level 3D Printer Using Various Materials.

Consumer-level 3D printers emit ultrafine and fine particles, though little is known about their chemical composition or potential toxicity. We report chemical characteristics of the particles in comparison to raw filaments and assessments of particle toxicity. Particles emitted from polylactic acid (PLA) appeared to be largely composed of the bulk filament material with mass spectra similar to the PLA monomer spectra. Acrylonitrile butadiene styrene (ABS), extruded at a higher temperature than PLA, emitted vastly more particles and their composition differed from that of the bulk filament, suggesting that trace additives may control particle formation. In vitro cellular assays and in vivo mice exposure all showed toxic responses when exposed to PLA and ABS-emitted particles, where PLA-emitted particles elicited higher response levels than ABS-emitted particles at comparable mass doses. A chemical assay widely used in ambient air-quality studies showed that particles from various filament materials had comparable particle oxidative potentials, slightly lower than those of ambient particulate matter (PM2.5). However, particle emissions from ABS filaments are likely more detrimental when considering overall exposure due to much higher emissions. Our results suggest that 3D printer particle emissions are not benign and exposures should be minimized.

Rapid determination of trace nitrofurantoin in cosmetics by surface enhanced Raman spectroscopy using nanoarrayed hydroxyl polystyrene‐based substrate

AbstractThe safety of cosmetics attributing to the illegal addition of antibiotics for quick effect is a big concern nowadays. Nitrofurans, one of commonly added illegal antibiotics, are strictly banned in cosmetics in China. It is still a great challenge for the rapid and precise analysis of trace nitrofurans when facing various cosmetics with complicated matrices. Surface‐enhanced Raman spectroscopy (SERS) is emerging as a novel rapid on‐site analytical technique. In this work, an accurate SERS method was developed for the rapid analysis of trace nitrofurantoin in various cosmetics by use of nanoarrayed hydroxyl polystyrene (PS‐OH)‐based substrate. A series of characterizations indicated the successful synthesis of Au@PS‐OH substrate and the uniform distribution of gold nanoparticles on the substrate surface. The SERS substrate revealed good selectivity and reproducibility with an enhancement factor of 2.6×104. Finally, an analytical method for the determination of nitrofurantoin in cosmetics was established by SERS using Au@PS‐OH substrate coupling with efficient sample preparation process. It was satisfied that trace nitrofurantoin could be actually detected and quantified to be 1.77 and 7.74 mg/L in a mouthwash and rose‐mist sample, respectively, with good recoveries of 86.8‐106% and relative standard deviations of 0.9‐2.9%. The comparable analytical results for real samples were achieved by the traditional high‐performance liquid chromatography (HPLC) method, which validated the reliability of the proposed method. It is expected that this SERS method has great potential for the rapid and on‐site analysis of trace additives in cosmetics.

Experimental Study for Effects of Hydrate Products on Shrinkage Behaviour in Low Volume Blast Furnace Slag Cement Concrete

Blast furnace slag (BFS) cement concrete is reported to be prone to shrinkage cracking at high temperature in tropical climate. To solve this problem is important to extend BFS cement concrete which is known as a key to reduce carbon footprint in concrete production. This study focuses shrinkage reducing effects to increase gypsum and calcium carbonate in low volume BSF cement concrete as trace additives. Free shrinkage experiment and hydration analysis experiment are conducted to clarify the focused issues. These two experiments clarified that: i) increasing gypsum amount up to 4.5% of binder mass effectively reduced free shrinkage strain subjected to 30 degree of ambient temperature, ii) this free shrinkage reduction is considered due to restraining transformation of Ettringite to Monosulfate, which is known to lead serious volume reduction in hydrate products, iii) increased gypsum amount up to 4.5% appeared not a source of Delayed Ettringite Formation.