Effect of Temperature on Calcium Carbonate Deposition in Situ on Bamboo Fiber and Polymer Interfaces

The objective of this work was to investigate the effect of different reaction temperatures on the mechanical and surface (interface) properties of calcium-carbonate (CaCO3)-filled bamboo fibers and polypropylene (PP) composites. With an ionic reaction of sodium carbonate and calcium chloride aqueous solution at various bath temperatures, CaCO3 particles were successfully deposited in situ on bamboo fibers. Polymer composites were fabricated using treated bamboo fibers as the reinforcement and PP as the matrix. Tensile tests of single fibers and PP composites were performed to determine the mechanical properties at different conditions. Results showed that the treatments improved compatibility between bamboo fibers and PP matrix, and the crystallinity of inorganic materials was affected by the treatment temperature. Compared with the composites reinforced with untreated bamboo fibers, the tensile strength and modulus of composites reinforced with treated fibers increased by 14.58 and 19.66%, respectively

Arsenic, Fluoride and Iodine in Groundwater of China

Arsenicosis and fluorosis, two endemic diseases known to result from exposure to their elevated concentrations in groundwater of north China used by many rural households for drinking, have been major public health concerns for several decades. Over the last decade, a large number of investigations have been carried out to delineate the spatial distribution and to characterize the chemical compositions of high As and F groundwaters with a focus on several inland basins in north China. Findings from these studies, including improved understanding of the hydrogeological and geochemical factors resulting in their enrichments, have been applied to guide development of clean and safe groundwater in these endemic disease areas. Survey efforts have led to the recognition of iodine in groundwater as an emerging public health concern. This paper reviews the new understandings gained through these studies, including those published in this special issue, and points out the direction for future research that will shed light on safe guarding a long-term supply of low As and F groundwater in these water scarce semi-arid and arid inland basins of north China

Mechanical and Rheological Properties of Bamboo Pulp Fiber Reinforced High Density Polyethylene Composites: Influence of Nano CaCO3 Treatment and Manufacturing Process with Different Pressure Ratings

Article investigating the effect of the relative motion of nano CaCO3 reinforced bamboo pulp fiber (BPF)/HDPE composite components on the mechanical performance

Electroplating lithium transition metal oxides.

Materials synthesis often provides opportunities for innovation. We demonstrate a general low-temperature (260°C) molten salt electrodeposition approach to directly electroplate the important lithium-ion (Li-ion) battery cathode materials LiCoO2, LiMn2O4, and Al-doped LiCoO2. The crystallinities and electrochemical capacities of the electroplated oxides are comparable to those of the powders synthesized at much higher temperatures (700° to 1000°C). This new growth method significantly broadens the scope of battery form factors and functionalities, enabling a variety of highly desirable battery properties, including high energy, high power, and unprecedented electrode flexibility

Polarization rotation enhanced upon optical tunneling through photonic crystals filled with Bi:YIG\SiO

Two-dimensional photonic crystals (PCs) have a good modulation effect on the in-plane propagating light field, which enhance the Faraday rotation of MO material. However, for the axially propagating light field, the effect of PCs is limited. To overcome this, we present a method that is based on optical tunneling, and a large Faraday rotation and small ellipticity can be achieved through a Bi:YIG nanoparticle that is coated with a low-index SiO2 material. This model is composed of a Glass matrix of two-dimensional PCs filled with a Bi:YIG\ SiO2 nanoparticle at the point defect, which is compatible with traditional processes. The conversion of linear polarized light propagating axially was simulated by the finite difference time domain algorithm with MATLAB. The suggested model has Faraday rotation and an ellipticity of θF = 24.06° and εF = 0.012 for the wavelength λ = 975 nm

Preparation and Characterization of Hydroxyapatite-Poly(Vinyl Alcohol) Composites Reinforced with Cellulose Nanocrystals

Hydroxyapatite/poly(vinyl alcohol) (Hap/PVA) composites have been proposed as a promising biomaterial for use in articular cartilage repair. In this study, HAp/PVA composite gels reinforced with cellulose nanocrystals (CNC) were prepared using the freeze/thaw method. The influence of CNC as a reinforcement on the structure of composite gels was investigated via Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The mechanical properties and thermal stability of the composite gels were also studied. The FT-IR and XRD results indicated that the HAp/PVA/CNC composite gels were formed by hydrogen bonding. SEM morphology showed that the CNC served as an enhancement phase that interpenetrated the network of the HAp/PVA composite gels. The tensile strength and tensile modulus of the composites improved with increasing dosage of CNC. The thermal stability measurements indicated that the thermal stability of the HAp/PVA composites was slightly improved with the addition of the CNC

Simulation Study on Performance Optimization of Magnetic Nanoparticles DC Thermometry Model

Magnetic nanoparticles (MNPs) can work as temperature sensors to realize temperature measurement due to the excellent temperature sensitivity of their magnetization. This paper mainly reports on a performance optimization method of MNPs DC thermometry model. Firstly, by exploring the influencing factors of MNPs magnetization temperature sensitivity, it is found that the optimal excitation of the magnetic field to make the temperature sensitivity of MNPs reach their optimal value is, approximately, inversely proportional to the particle size of MNPs. Then, the temperature sensitivity of MNP magnetization is modulated by adding appropriate DC bias magnetic field in the original triangular wave excitation field, to optimize the original DC thermometry model based on MNP magnetization. The simulation results show that the temperature measurement performance of small-size MNPs can be significantly improved. In short, this paper optimizes the temperature measurement performance of the original DC thermometry model based on MNP magnetization and provides a new application idea for temperature measurement of small-size MNPs

Developing and Evaluating Composites Based on Plantation Eucalyptus Rotary-cut Veneer and High-density Polyethylene Film as Novel Building Materials

To achieve value-added utilizations of plantation timbers, eucalyptus veneer/high-density polyethylene film composites were prepared, with process-factors (PF) (hot-pressing temperature, HT; hot-pressing duration, HD; hot-pressing pressure, HP; HDPE-film content, HC) and composite-properties (CP) (water-resistant bonding-strength, BS; modulus of rupture, MOR; modulus of elasticity, MOE) investigated. According to thermal analyses, 140 to 180 °C was appropriate for HT. Based on statistical analyses, HD was easier to affect CP, while MOE was easier to be affected by PF. Quantitative relationships between PF and CP were determined by the neural-network (ANN) modeling. In ANN simulation surveys, CP displayed Gaussian distributions (R2 > 0.9) when PF changed in current ranges, with positive correlations between BS and MOR (R2 ≈ 0.5). Combining ANN and the genetic-algorithm, optimal processes (HT, 160 °C; HD, 50 s/mm; HP, 1.3 MPa; HC, 6 layers) were found, and optimal results (BS, 1.30 MPa; MOR, 86.94 MPa; MOE, 8.33 GPa) were comparable to various reported poplar-plywoods. Microscopic images demonstrated that composite interfaces were formed by the mechanical interlocking. The optimal BS attained Chinese standards for water-resistant plywoods, so proposed composites can serve as water-resistant and formaldehyde-free building materials for furniture and interior design

Utilization of Polypropylene Film as an Adhesive to Prepare Formaldehyde-free, Weather-resistant Plywood-like Composites: Process Optimization, Performance Evaluation, and Interface Modification

To develop formaldehyde-free wood-based composites, plywood-like composites (WV/PPF) were prepared using wood veneer (WV) with polypropylene film (PPF) as a novel formaldehyde-free, water-resistant adhesive. To prepare WV/PPF, the effects of hot-pressing conditions (temperature, 165 to 195 °C; pressure, 0.9 to 1.3 MPa; duration, 40 to 70 s/mm; and adhesive dosage between adjacent WVs, 100 to 200 g/m2) were investigated. Results showed that conditions at 180 °C, 0.9 MPa, 70 s/mm, and 150 g/m2 gave WV/PPF desirable physical-mechanical properties. Then, WV/PPF was compared with plywood-like composites using, respectively, polyethylene film (PEF), urea-formaldehyde resin (UFR), and phenol-formaldehyde resin (PFR) as adhesives. Results showed that the physical-mechanical properties of WV/PPF were favored over WV/PEF and WV/UFR, and were comparable to those of WV/PFR. Maleic anhydride grafted polypropylene (MAPP) or γ-aminopropyltriethoxysilane (APTES) surface modification of WV was performed to enhance the interface compatibility of WV/PPF. Results showed that the physical-mechanical properties of modified WV/PPF were favored over those of WV/PFR; MAPP modification was better for shear properties, while APTES modification was better for dimensional stability and flexural properties. Overall, the environmental and technological benefits demonstrated the potential of WV/PPF as a novel construction and building material