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排序方式: 共有930条查询结果,搜索用时 15 毫秒
811.
Fazlhan Ylmaz
mer Aydnlolu Hüseyin Benli Gamze Kahraman Muhammed brahim Bahtiyari 《Coloration Technology》2020,136(2):147-152
In this study, the objective was to ensure anti‐bacterial properties for originally coloured wools with naturally sourced garlic stem extracts. In addition, zinc chloride‐based treatment was also carried out. The aim was to retain the original colours of the wool fibres during these treatments. The effects of both treatments were evaluated in terms of colour changes in the wool fibres. It was found that the colour changes caused by the treatments were high in white/ecru fibres but more limited in black fibres. The colour differences between the treated and untreated black fibres were near 1; they were also quite high in white/ecru fibres. The anti‐bacterial properties of the treated wool fibres against two bacteria species, one gram‐negative and one gram‐positive, were also investigated. It was observed that zinc chloride‐based treatment ensured significant anti‐bacterial efficiencies against the bacteria tested and 99.9% bacterial reduction in all cases. However, the anti‐bacterial effects of garlic stem extract‐based treated wool fibres were limited. It was observed that treatment of wool fibres with garlic stem extracts resulted in no anti‐bacterial efficiency against Escherichia coli but did provide some anti‐bacterial capability against Staphylococcus aureus. The highest bacterial reduction of S. aureus was 80.7% in originally brown‐coloured wool fibre. 相似文献
812.
Total oxidation of methane over doped nanophase cerium oxides 总被引:7,自引:0,他引:7
The formation of solid solutions of cerium oxide with the oxides of calcium, manganese, or neodymium enhances the catalytic
activity of cerium oxide for the total oxidation of methane, whereas solid solutions with lead oxide showed an opposite effect.
Reasons for this are discussed in terms of oxygen vacancy concentrations and mobilities, local structure configurations, number
of oxidation states of dopant, and electron transfer properties. The effects of increased oxygen ion mobility and a more beneficial
local structure support the increased catalytic activity for the calcium- and neodymium-doped cerium oxide samples. In addition,
a reduced energy for charge transfer from oxygen to cerium supports a higher activity for the calcium-doped sample. The activity
data were fitted to an Arrhenius equation, and the apparent activation energies were found to be between 110 and 130 kJ/mol.
The particle sizes and the BET areas of the samples were only little affected by the reactor runs, and none of the samples
were subjected to phase changes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
813.
814.
The effects of xylenes/ethanol solvent mixtures on lanthanum-modified lead zirconate titanate (PLZT) nonaqueous suspensions were investigated by measuring sediment height, viscosity, and adsorption of dispersant. Well-dispersed colloidal suspensions were obtained in xylene-rich solvents with a minimum amount of menhaden fish oil as a dispersant. It was also shown that adsorption of dispersant on particle surfaces strongly depends on selection of solvent(s). The ratio of solvent mixture affects PLZT solids content of unfired tapes, in which using insufficient as well as excess dispersant could decrease the packing density of particles. Solubility of other organic additives, such as binder, was also considered when selecting a xylene/ethanol ratio. 相似文献
815.
The storage of thermal energy in the form of sensible and latent heat has become an important aspect of energy management with the emphasis on efficient use and conservation of the waste heat and solar energy in industry and buildings. Latent heat storage is one of the most efficient ways of storing thermal energy. Solar energy is a renewable energy source that can generate electricity, provide hot water, heat and cool a house, and provide lighting for buildings. Paraffin waxes are cheap and have moderate thermal energy storage density but low thermal conductivity and, hence, require a large surface area. Hydrated salts have a larger energy storage density and a higher thermal conductivity. In response to increasing electrical energy costs and the desire for better lad management, thermal storage technology has recently been developed. The storage of thermal energy in the form of sensible and latent heat has become an important aspect of energy management with the emphasis on the efficient use and conservation of the waste heat and solar energy in the industry and buildings. Thermal storage has been characterized as a kind of thermal battery. 相似文献
816.
Alan B. Ilicic Mohammad S. Dara David P. Wilkinson Khalid Fatih 《Journal of Applied Electrochemistry》2010,40(12):2125-2133
Advancements in the performance of the direct methanol redox fuel cell (DMRFC) were made through anolyte/catholyte composition
and cell temperature studies. Catholytes prepared with different iron salts were considered for use in the DMRFC in order
to improve the catholyte charge density (i.e., iron salt solubility) and fuel cell performance. Following an initial screening
of different iron salts, catholytes prepared with FeNH4(SO4)2, Fe(ClO4)3 or Fe(NO3)3 were selected and evaluated using electrolyte conductivity measurements, cyclic voltammetry and fuel cell testing. Solubility
limits at 25 °C were observed to be much higher for the Fe(ClO4)3 (>2.5 M) and Fe(NO3)3 (>3 M) salts than FeNH4(SO4)2 (~1 M). The Fe(ClO4)3 catholyte was identified as a suitable candidate due to its high electrochemical activity, electrochemical reversibility,
observed half-cell potential (0.83 V vs. SHE at 90 °C) and solubility. DMRFC testing at 90 °C demonstrated a substantial improvement
in the non-optimized power density for the perchlorate system (79 mW cm−2) relative to that obtained for the sulfate system (25 mW cm−2). Separate fuel cell tests showed that increasing the cell temperature to 90 °C and increasing the methanol concentration
in the anolyte to 16.7 M (i.e., equimolar H2O/CH3OH) yield significant DMRFC performance improvements. Stable DMRFC performance was demonstrated in short-term durability tests. 相似文献
817.
The influence of natural zeolite on biogenic amines (BAs) and ammonia (AMN) production by eight common gram negative and positive foodborne pathogens (FBP) were investigated in histidine decarboxylase broth (HDB). Presence of 1% zeolite in the HDB resulted in significantly higher AMN production. Histamine (HIS) production by gram positive bacteria was as low as 0.5 mg/L, whereas Escherichia coli produced 18.96 mg/L of HIS. The use of zeolite also significantly suppressed HIS accumulation by E. coli, Pseudomonas aeruginosa, S. paratyphi A (P < 0.05), although zeolite addition stimulated HIS production by K. pneumonia and Aeromonas hydrophila. The range of tyramine (TYR) production by gram positive bacteria was 1.19 and 4.06 mg/L for Enteroccus faecalis and Listeria monocytogenes respectively. The results of study showed that the effect of zeolite on BAs and AMN production was dependent on bacterial strains, as well as zeolite concentrations used. Practical Application: Natural zeolites are the main absorptive, low-cost material used in agriculture and industry. Although the effect of zeolite on ammonia formation in some industrial systems is well known, there is limited information regarding the impact of zeolite on biogenic amine (BA) production by foodborne pathogens. The data presented in this article will help us to understand the impact of natural zeolite on BA and ammonia production by eight common foodborne pathogens. 相似文献
818.
Arda Aytimur İbrahim Uslu Emre Çınar Serhat Koçyiğit Fatih Özcan Ahmet Akdemir 《Ceramics International》2013,39(2):911-916
In this study, boron doped calcium stabilized bismuth cobalt oxide nanocrystalline ceramic powders were successfully prepared from aqueous boric acid containing calcium–bismuth–cobalt acetate/poly(vinyl alcohol) hybrid precursor polymer solutions. Then, obtained ceramic powders were characterized via FT-IR, XRD, and SEM techniques. According to X-ray results, fcc and bcc phases coexist in the samples of the nanocrystalline ceramic powders. fcc peaks became sharper and bcc peak decreased with increasing boron content. Structural parameters for face centered cubic structure were calculated using the Scherrer equation. Moreover, dislocation densities and microstrain values were calculated for the nanocrystalline powder samples. 相似文献
819.
Two dithienylpyrroles based on azo dyes, namely 2,5′-dimethyl-[4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-phenyl]azobenzene (SNS-AB2) and 2,5′-dimethyloxy-[4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-phenyl]azobenzene (SNS-AB3), were synthesized and their corresponding polymers (PSNS-AB2 and PSNS-AB3) were successfully obtained via electropolymerization. The monomers have lower oxidation potentials (0.75 V and 0.80 V vs. Ag/AgCl for SNS-AB2 and SNS-AB3, respectively) when compared to their analogous. Both monomers exhibited photoisomerism properties under irradiation at 360 nm. During the irradiation process, for example, the color of SNS-AB3 changes from yellow to greenish yellow. The electroactive polymer films have well defined and reversible redox couples with a good cycle stability in both aqueous and organic solutions. The polymer films also exhibited electrochromic behaviors; color changes from yellowish green to dark green for the PSNS-AB2 (λmax = 435 nm and Eg = 2.31 eV) and from mustard color to green for PSNS-AB3 (λmax = 430 nm and Eg = 2.34 eV). Furthermore, the soluble polymers demonstrated different hues of yellow and green colors. 相似文献
820.
Onur Gezgin Fatih Tulumbacı Hazal Özer Yagmur Sener 《Journal of Adhesion Science and Technology》2018,32(15):1724-1731
Objectives: The aim of the present study is to evaluate the released residual monomers from composite resins that contain different proportions of bioactive glass (BAG). Methods: Experimental resin composites were prepared by a resin matrix (50% BisGMA and 50% TEGDMA) and inorganic filler with BAG (5, 10 and 30%). Each resin composite was placed in the tooth cavity (n = 5). After polymerisation, samples were immediately immersed in 75% ethanol and 25% deionised water (6 ml) at 37 °C. Residual monomers (Bis-GMA, TEGDMA, HEMA and UDMA) that were eluted from the composites for 10 m, 1 h, 1 d, 7 d and 30 d were analysed by high-performance liquid chromatography (HPLC). The data were analysed with one-way ANOVA and Tukey HSD at a p < 0.05 significance level. Results: Among the time periods, the fastest released residual monomer was observed in the 10 m elution. The highest amount of released residual monomer from all groups (except the control group) was TEGDMA, whereas this was HEMA for the control group. The amounts of residual monomers eluted from BAG30 were significantly higher than other groups (p < 0.05). Conclusions: The release of the monomer increases in accordance with the increased BAG addition to the composite resins. 相似文献