Design and synthesis of foam glasses from recycled materials

Recycling has emerged as an environmental key point due to the diminishing of natural resources and the generation of ever-increasing amounts of industrial solid wastes. Glass wastes are among the materials that attract great interest in the recycling concept. This work presents the results of foams production from four series of compositions. The first series comprises powders of a sodium-calcium-silicate sheet glass cullet as the main component, an alkali-earth aluminosilicate glass as an additive, and a reagent grade silicon carbide (SiC) powder as gassing agent. In the second series, the glass cullet was used in combination with fly ashes (FLA) as main components, while SiC waste from abrasive paper served as foaming agent. In the third and fourth series, carbonates (calcite and dolomite) were used for foaming powder mixtures composed of sheet glass cullet and FLA, and powdered cathode ray tube panel glasses, respectively. All the processing parameters, including the main components, the nature and content of foaming agents are shown to play a crucial role on the foaming ability and final properties of the glass foams.     

Mass transfer and electrocrystallization analyses of nanocrystalline nickel production by pulse plating

A comparison between the experimental process parameters employed for the pulse plating of nanocrystalline nickel and the solution-side mass transfer and electrokinetic characteristics has been carried out. It was found that the experimental process parameters (on-time, off time and cathodic pulse current density) for cathodic rectangular pulses are consistent and within the physical constraints (limiting pulse current density, transition time, capacitance effects and integrity of the waveform) predicted from theory with the adopted postulates. This theoretical analysis also provides a means of predicting the behaviour of the process subject to a change in the system, kinetic and process parameters. The product constraints (current distribution, nucleation rate and grain size), defined as the experimental conditions under which nanocrystalline grains are produced, were inferred from electrocrystallization theory. High negative overpotential, high adion population and low adion surface mobility are prerequisites for massive nucleation rates and reduced grain growth; conditions ideal for nanograin production. Pulse plating can satisfy the former two requirements but published calculations show that surface mobility is not rate-limiting under high negative overpotentials for nickel. Inhibitors are required to reduce surface mobility and this is consistent with experimental findings. Sensitivity analysis on the conditions which reduce the total overpotential (thereby providing more energy for the formation of new nucleation sites) are also carried out. The following lists the effect on the overpotential in decreasing order: cathodic duty cycle, charge transfer coefficient, Nernst diffusion thickness, diffusion coefficient, kinetic parameter () and exchange current density.Nomenclature A constant employed in Fig. 8, (nFi₀)/(RT _e C _a)(s^–1) - B constant in Equation 38 (V²) - C cation concentration (molcm^–3) - C _a capacitance of double layer (µFcm^–2) - C _s cation surface concentration (molcm^–3) - C _s ^* dimensionless cation surface concentration, C _s/C (–) - C cation bulk concentration (molcm^–3) - D diffusion coefficient of cation (cm²s^–1) - E total applied potential (V) - E ⁰ standard cell potential (V) - F Faraday constant (Cmol^–1) - function defined in Appendix C(–) - Fr frequency of waveform (Hz) - f _i,p function defined in Appendix C for pth period (–) - f _i, function defined in Appendix C for p period (–) - G _j function defined in Appendix B (–) - gi function defined in Appendix B (–) - i current density (Acm^¨) - i _ac unsteady fluctuating a.c. current density (Acm^–2) - i _c capacitance current density (Acm^–2) - i _dc steady time-averaged d.c. current density (Acm^–2) - i _F Faradaic current density (Acm^–2) - i _lim limiting d.c. current density (Acm^–2) - i ₀ exchange current density (Acm^–2) - i _PL limiting pulse current density, i ₁{Cs = 0 at t = (p – 1) T + t ₁(Acm^–2) - i ₁ cathodic pulse current density (Acm^–2) - i ₂ relaxed or low current pulse current density (Acm^–2) - iin anodic pulse current density (Acm^–2) - i ^* dimensionless current density, i/|i _lim| (–) - i ₀ ^* dimensionless exchange current density, i _dc/|i _lim| (–) - i _dc ^* dimensionless steady time-averaged d.c. current density, i _dc/|i _lim| (–) - i _PL ^* dimensionless limiting cathodic pulse current density, i _PL/|i _lim| (–) - i _PL,p ^* dimensionless limiting pulse current density at pth period, i ₁(C _s = 0)/|i _lim| (–) - i _PL, ^* dimensionless limiting pulse current density for p , i ₁(C _s = 0)/|i _lim| (–) - i ₁ ^* dimensionless cathodic pulse current density, i ₁/|i _lim| (–)     

Hard x-ray transmission crystal spectrometer at the OMEGA-EP laser facility

The transmission crystal spectrometer (TCS) is approved for taking data at the OMEGA-EP laser facility since 2009 and will be available for the OMEGA target chamber in 2010. TCS utilizes a Cauchois type cylindrically bent transmission crystal geometry with a source to crystal distance of 600 mm. Spectral images are recorded by image plates in four positions, one IP on the Rowland circle and three others at 200, 400, and 600 mm beyond the Rowland circle. An earlier version of TCS was used at LULI on experiments that determined the x-ray source size from spectral line broadening on one IP positioned behind the Rowland circle. TCS has recorded numerous backlighter spectra at EP for point projection radiography and for source size measurements. Hard x-ray source size can be determined from the source broadening of both K shell emission lines and from K absorption edges in the bremsstrahlung continuum, the latter being a new way to measure the spatial extent of the hard x-ray bremsstrahlung continuum.     

同步辐射高分辨率衍射光束线的设计

介绍了第三代同步辐射高分辨率X射线衍射光束线的总体设计。给出了高分辨率衍射的基本原理并描述了获得确定光子能量的近平行高强度X射线光束线所必需的光学元件。特别是用X射线动力学理论,解释了双晶及四次反射晶体单色器。作为一个实例,介绍了将于2009年开始在德国汉堡运行的一个新的同步辐射源PETRAⅢ的高分辨率衍射(HighRes)光束线的设置情况。通过优化光学部件,对微米尺寸光束,q空间的分辨减小到Δq=10^-5 nm^-1,光通量大于10¹¹ cts/s。     

Efficiency of activated carbon to transform ozone into *OH radicals: influence of operational parameters

Based on previous findings (Jans, U., Hoigné, J., 1998. Ozone Sci. Eng. 20, 67-87), the activity of activated carbon for the transformation of ozone into *OH radicals including the influence of operational parameters (carbon dose, ozone dose, carbon-type and carbon treatment time) was quantified. The ozone decomposition constant (k(D)) was increased by the presence of activated carbon in the system and depending on the type of activated carbon added, the ratio of the concentrations of *OH radicals and ozone, the R(ct) value ([*OH]/[O3]), was increased by a factor 3-5. The results obtained show that the surface chemical and textural characteristics of the activated carbon determines its activity for the transformation of ozone into *OH radicals. The most efficient carbons in this process are those with high basicity and large surface area. The obtained results show that the interaction between ozone and pyrrol groups present on the surface of activated carbon increase the concentration of O2*- radicals in the system, enhancing ozone transformation into *OH radicals. The activity of activated carbon decreases for extended ozone exposures. This may indicate that activated carbon does not really act as a catalyst but rather as a conventional initiator or promoter for the ozone transformation into *OH radicals. Ozonation of Lake Zurich water ([O3] = 1 mg/L) in presence of activated carbon (0.5 g/L) lead to an increase in the k(D) and R(ct) value by a factor of 10 and 39, respectively, thereby favouring the removal of ozone-resistant contaminants. Moreover, the presence of activated carbon during ozonation of Lake Zurich water led to a 40% reduction in the content of dissolved organic carbon during the first 60 min of treatment. The adsorption of low concentrations of dissolved organic matter (DOM) on activated carbon surfaces did not modify its capacity to initiate/promote ozone transformation into *OH radicals.     

Long term effects of salt on activity, population structure and floc characteristics in enriched bacterial cultures of nitrifiers

The effect of salinity on the activity, the composition of nitrifiers and floc characteristics of nitrifying sludge was studied. Non-adapted and adapted (to 10 g NaCl-Cl⁻/L for one year) enriched cultures of nitrifiers were tested in three sequencing batch reactors. Salt was increased gradually with 5 up to 40 g Cl⁻/L.No difference in steady state activity was observed between the adapted and non-adapted sludge. The activities of ammonia and nitrite oxidizers dropped 36% and 11%, respectively, at salt concentrations of 10 g Cl⁻/L. At 40 g Cl⁻/L inhibition reached 95% of salt free activity for ammonia and nitrite oxidizers in both adapted and non-adapted reactors. Nitrosomonas europaea and Nitrobacter sp. (fluorescent in situ hybridization) were the only nitrifiers present at high salt levels. Increased salt concentrations resulted in better settling characteristics of the nitrifying sludge. After 118 days the sludge was brought back to the initial conditions (0 g Cl⁻/L for non-adapted and 10 g Cl⁻/L for adapted). Despite the change in population composition similar kinetics as before the salt stress were observed.     

Dietary CLA affects lipid metabolism in broiler chicks

A total of 120 three-wk-old broiler chicks were randomly assigned to three diets containing 0, 2, or 3% CLA and fed for 5 wk. Fat content and FA composition of liver, plasma, and feces were analyzed. Key enzymes involved in FA synthesis and catabolism in liver, TG, cholesterol, and FFA content of plasma were also determined. Dietary CLA increased TG, total cholesterol, and HDL cholesterol levels in plasma. The increased plasma TG level could be caused by increased FA synthesis in the liver after CLA feeding, because the activity of FA synthase in the liver increased after dietary CLA treatment. Dietary CLA changed the FA composition of feces but had no effect on fat content. Compared to the amounts of linoleic and linolenic acids present in the control diet, the amounts excreted into the feces of CLA-treated birds were significantly higher. Liver weights of broilers significantly increased after CLA feeding, but there was no difference in liver fat content among the different CLA treatments. CLA treatment did not influence total FFA content in plasma; however, there was a significant difference in the composition of FFA. Dietary CLA reduced the content of linoleic and arachidonic acids in both plasma and liver.     

An attempt to bridge the pressure and material gap with a disperse model catalyst for low-temperature alkane reforming

Pt black was exposed to n>-hexane/H₂ mixtures between 483 and 663 K followed by O₂ and H₂ treatments at 603 K. XP and UP spectra were measured without exposing the samples to air. 20–30% carbon accumulated after hydrocarbon exposures. O₂ removed most carbon. The surface C content increased after a subsequent contact with H₂, C 1s showing more atomic carbon as opposed to graphite after n-hexane exposure. Anisotropic recrystallization of Pt black favoring (220) and (311) lattice planes occurred under hydrogen-rich conditions. Both findings were attributed to a H₂-induced solid-state rearrangement; H atoms penetrating into the crystal lattice, force subsurface carbon and oxygen atoms to the surface and a concomitant restructuring would occur. Thus another hydrogen effect has been recognized, leading to structures favorable for skeletal reactions of alkanes.