Structure Evolution and Electrical Properties of Y3+‐Doped Ba1−xCaxZr0.07Ti0.93O3 Ceramics

Lead free piezoelectric ceramics of Y³⁺‐doped Ba_1?xCa_xZr_0.07Ti_0.93O₃ with x = 0.05, 0.10, and 0.15 were prepared. Composition and temperature‐dependent structural phase evolution and electrical properties of as‐prepared ceramics were studied systematically by X‐ray diffraction, Raman spectroscopy, impedance analyzer, ferroelectric test system, and unipolar strain measurement. Composition with x = 0.10 performs a good piezoelectric constant d₃₃ of 363 pC/N, coercive field E_c of 257 V/mm, remanent polarization P_r of 14.5 μC/cm², and a Curie temperature T_m of 109°C. High‐resolution X‐ray diffraction was introduced to indicate presence of orthorhombic phase. Converse piezoelectric constant d₃₃* of x = 0.10 composition performed better temperature stability in the range from 50°C to 110°C. That means decreasing orthorhombic–tetragonal phase transition temperature could be an effective way to enlarge its operating temperature range.     

Plasma surface graft of acrylic acid onto a porous poly(vinylidene fluoride) membrane and its riboflavin permeation

Acrylic acid was grafted onto the surface of commercial poly(vinylidene fluoride) (PVDF) membrane using plasma polymerization techniques. Graft reaction was confirmed by X-ray photoelectron spectroscopy (XPS) spectra and attenuated total reflectance Fourier transform infrared spectra. Grafting rate was dependent on plasma exposure time. For argon plasma at 30 W, grafting rate decreased after maximum rate was observed at 30 s exposure. PVDF membrane with 30 s plasma exposure and subsequently grafted with acrylic acid (AA-3) showed the greatest O_1s/F_1s area ratio in XPS spectra. Thus its graft density and degree of polymerization were the largest among the graft membranes. Permeation of riboflavin through all poly(acrylic acid)-g-PVDF membranes showed a decrease in permeability of riboflavin in pH 4–5. © 1996 John Wiley & Sons, Inc.     

Friction and wear behavior of graphite fiber-reinforced composites

Friction and wear behavior of continuous graphite fiber composites was studied for different fiber orientations against the sliding direction. The effect of fiber orientation on friction and wear of the composite and on deformation of the counterface was investigated experimentally. A pin on disk type testing machine was built and employed to generate friction and wear data. A graphite fiber composite plate was produced by the bleeder ply molding in an autoclave and machined into rectangular pin specimens with specific fiber orientations, i.e., normal, transverse, and longitudinal directions. Three different wear conditions were employed for two different periods of time, 24 and 48 hours. The wear track of the worn specimens and the metal counterface was examined and a scanning electron microscope (SEM) to observe the damaged fibers on the sliding surface of the specimen and wear film generation on the counterface. A wear mechanism of the continuous graphite fiber composite during sliding wear is proposed based on the experimental results.     

Green Tea Formulations with Vitamin C and Xylitol on Enhanced Intestinal Transport of Green Tea Catechins

The effect of green tea formulated with vitamin C and xylitol on intestinal cell transport of gallated and nongallated catechin was studied. The transport of catechins from both apical to basolateral and basolateral to apical directions was measured. The effect of vitamin C (4, 10, 20 ppm), xylitol (11, 27.5, 55 ppm), and combinations of both on the intestinal transport rate of catechins was examined. The efflux value (Pb→a/Pa→b) of (–)‐epigallocatechin (EGC), (–)‐epigallocatechin gallate (EGCG), (–)‐epicatechin (EC), and (–)‐epicatechin gallate (ECG) was 0.26, 0.22, 1.22, and 0.17, respectively, indicating that EC appeared to be less absorbed compared with other catechins. The addition of xylitol (11, 27.5, 55 ppm) and vitamin C (4, 10, 20 ppm) and in combination enhanced transport rate of nongallated catechins such as EC and EGC. For EC, vitamin C was revealed to be the most effective on intestinal transport, implying the inhibition of the efflux transport mechanism of EC. Intestinal transport of gallated catechins significantly increased from catechins formulated with vitamin C and xylitol in a dose‐dependent manner compared to the catechin‐only formulation. Results provide a potential strategy to enhance the delivery and bioavailability of catechins in humans by modulating green tea formulation with vitamin C and xylitol.     

Rapid and Sensitive Immunochromatographic Strip for On‐site Detection of Sulfamethazine in Meats and Eggs

A rapid immunochromatographic (ICG) strip based on a conjugate of colloidal gold and monoclonal antibody (mAb) was developed for the rapid, sensitive, and on‐site detection of sulfamethazine in meat and egg samples. The detection limit of the ICG strip is 2 ng/mL, and the assay can be completed in 10 min. A cross‐reactivity test indicated that the ICG strip was highly specific to sulfamethazine with no cross‐reaction with sulfonamide compounds and other antibiotics. The results of the recovery test from meat and egg samples spiked with sulfamethazine were in good agreement with those obtained by the indirect competitive enzyme‐linked immunosorbent assay. These results demonstrated that the ICG strip can be used as a rapid and qualitative tool for on‐site screening of sulfamethazine in meat and egg samples.     

Effect of the concentration of diphenyloctyl phosphate as a flame-retarding additive on the electrochemical performance of lithium-ion batteries

We selected diphenyloctyl phosphate (DPOF) as a flame-retardant and plasticizer, and studied the influence of different amounts of the DPOF additive on the electrochemical performance of lithium-ion batteries. The electrochemical cell performances of the additive-containing electrolytes in combination with a cell comprising an LiCoO₂ cathode and mesocarbon microbeads (MCMB) anode were tested in coin cells. The cyclic voltammetry (CV) results showed that the oxidation potential of the electrolyte containing DPOF in the concentration range from 10 to 30 wt.% is about 4.75-5.5 V versus Li/Li⁺. In the present work, a DPOF content of 10 wt.% in the 1.15 M LiPF₆/EC:EMC (4:6 by vol.%) electrolyte turned out to be the optimum condition for the improvement of the electrochemical cell performance, due to the decrease of the irreversible capacity during the first cycle and decrease of the charge-transfer resistance after 40 cycles.     

Mercury and Fatty Acids in Canned Tuna, Salmon, and Mackerel

ABSTRACT: Canned tuna ( n = 240), salmon ( n = 16), and mackerel ( n = 16) were analyzed for mercury and fatty acids. Average mercury levels were 188, 45, and 55 ppb, respectively, and below the FDA Action Level of 1000 ppb. "Light tuna in water" contained lower mercury (x = 54 ppb) compared with "white/albacore tuna in water," which contained higher eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) x= 711 mg/100 g wet tissue). Mercury residues in salmon (x = 45 ppb) and mackerel (x = 55 ppb) were lower than in tuna products, but the EPA/DHA levels were higher (salmon, ×= 1623 mg/100 g wet tissue; mackerel, ×= 851 mg/100 g wet tissue). Information from this study will help women of childbearing age to limit their intake of mercury while obtaining healthy fats from fish.     

First dicadmium(II) complex of tripodal amide ligand with one edge-sharing monocapped octahedral geometry

A new dicadmium(II) complex [Cd₂(L)₂(H₂O)₂](NO₃)₄ · 8H₂O (1) with the tripodal amide ligand L (tris[3-aza-2-oxo-4-(2-pyridyl)butyl]amine) was synthesized and structurally characterized. Complex 1 is revealed as a dinuclear 2:2 (Cd:L) complex, in which each cadmium(II) ion is hepta-coordinated with the coordination surrounding of distorted monocapped octahedral geometry. Two cadmium(II) ions are dibridged by two carbonyl μ-O atoms forming a Cd₂(μ-O)₂ parallelogram-type moiety. Interestingly, the dinuclear coordination sphere can be seen as resulting from the fusion of two distorted monocapped octahedral [Cd(L)(H₂O)]²⁺ units through sharing one edge originated from the two carbonyl μ-O atoms as a first example. Comparative NMR, IR and FAB-mass data of 1 are also discussed.     

Coherence technique for noise reduction in rotary compressor

The noise and vibration of a rotary compressor, a type of multi-input, single output system, are generally studied through frequency analysis. Although this method is effective in analyzing frequency components, using this method to identify the specific source of the noise (4 kHz to 6 kHz) is difficult. Hence, noise source should be studied systematically. In this study, a coherence analysis method based on systems analysis is used to identify the compressor noise source. Compressor noise source is identified through the coherence between the vibration signals on the shell of the compressor and the noise signal at one point near the compressor (1 m away from the compressor). A one-third octave band is employed for frequency analysis. The design of experiment is conducted to identify possible noise factors, such as volume, size, and neck area of the resonator in the compressor cylinder. Analysis showed that noise was generated from the cavity of the cylinder and the muffler inside the rotary compressor. A new type of muffler was applied to the rotary compressor to verify this finding. Noise was dramatically reduced.