Rate Of Mass Increase Research Articles

From Halos to Galaxies. VII. The Connections between Stellar Mass Growth History, Quenching History, and Halo Assembly History for Central Galaxies

The assembly of galaxies over cosmic time is tightly connected to the assembly of their host dark matter halos. We investigate the stellar mass growth history and the chemical enrichment history of central galaxies in the Sloan Digital Sky Survey Mapping Nearby Galaxies at Apache Point Observatory. We find that the derived stellar metallicity of passive central galaxies is always higher than that of the star-forming ones. This stellar metallicity enhancement becomes progressively larger toward low-mass galaxies (at a given epoch) and earlier epochs (at a given stellar mass), which suggests strangulation as the primary mechanism for star formation quenching in central galaxies not only in the local Universe but also very likely at higher redshifts up to z ∼ 3. We show that at the same present-day stellar mass, passive central galaxies assembled half of their final stellar mass ∼2 Gyr earlier than star-forming central galaxies, which agrees well with the semi-analytic model. Exploring the semi-analytic model, we find that this is because passive central galaxies reside in, on average, more massive halos with a higher halo mass increase rate across cosmic time. As a consequence, passive central galaxies are assembled faster and also quenched earlier than their star-forming counterparts. While at the same present-day halo mass, different halo assembly history also produces a very different final stellar mass of the central galaxy within, and halos assembled earlier host more massive centrals with a higher quenched fraction, in particular around the “golden halo mass” at 1012 M ⊙. Our results call attention back to the dark matter halo as a key driver of galaxy evolution.

Mechanical and durability performance of polyvinyl alcohol fiber hybrid geopolymer-portland cement concrete under freeze–thaw cycles

Cold winter temperatures at high latitudes in coastal regions lead to prolonged exposure of offshore concrete structures to freeze–thaw (F–T) damage, which significantly reduces the mechanical and durability properties of concrete. To improve the durability of concrete under F–T damage, this study investigated the combined effects of fly ash (FA) and bentonite on the frost resistance of polyvinyl alcohol fiber reinforced geopolymer concrete (PFRGC). The study comprehensively analyzed the effect of fly ash and bentonite content on the rate of mass change and compressive strength under various F–T damage conditions. In addition, uniaxial compressive tests were carried out at different stages of F–T damage and the resulting stress–strain curves and compressive properties were analyzed. Correlations between peak stress, peak strain, modulus of elasticity and deterioration time of the concrete were developed. SEM microscopy tests were also used to investigate the evolution of the internal microstructure and the morphological characteristics of the erosion products under freeze–thaw conditions. The results indicated that the change in concrete mass with a growing number of F–T cycles can be divided into two periods: a gentle increase and a faster increase. A continuous increase in the rate of mass increase was observed for the specimens containing fly ash and bentonite, while the compressive strength of these specimens continued to decrease. During F–T damage, the maximum stress decreased slightly and the maximum strain increased gradually as the volume of bentonite and fly ash increased. This study provides a theoretical basis and technical basis for the development of fly ash and bentonite to improve the frost durability of offshore structures.

Evolution of Electrochemical Impedance Spectra Characteristics of Cementitious Materials after Capturing Carbon Dioxide

The electrochemical parameters of cement-based materials with different water–cement ratios in carbon curing and water curing were measured with electrochemical impedance spectroscopy (EIS). The optimized circuit model and corresponding electrical parameters were obtained to illustrate the variation of the microstructure of cementitious materials after carbon capturing. The results show that, to a large extent, the semicircle diameter in the high frequency area gradually increased along with carbon curing and water curing. However, carbon curing showed a difference that the semicircle diameter in the high frequency appeared at the minimal value at 3 days, which was higher than that at 1 day and 7 days. This should be the result of the joint influence of water content and porosity in the cement matrix. It was also found that the mass increase rates of carbonation with water–cement ratios of 0.4, 0.5, and 0.6 were basically stable at 3.4%, 5.0%, and 5.5%, respectively. The electrochemical parameters ρct2 of cement mortar corresponding to carbon curing were around three times that of water curing specimens, mainly due to the reduction of soluble materials and refinement of connecting pores in the microstructure of cementitious materials. A quadratic function correlation between the mass increase rate and ρct2 in the carbonation process of cement mortar was built, which proved that EIS analysis could be applied to monitor the carbon capturing of cement-based materials, either for newly mixed concrete or for recycled concrete aggregates.

Research on the sulfate resistance of cement-based materials incorporating dolomite powder

The effects of dolomite powder on the sulfate resistance of cement-based materials with water-binder ratio (w/b) of 0.55 and 0.36 were investigated in this manuscript. Scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and pressure testing machine were used to determine the apparent morphology, micro-morphology, mass increase rate, flexural strength and compressive strength of cement-based materials containing dolomite powder. The sulfate resistance of mortars was improved with increasing dolomite powder dosage. Generally, the flexural strength and compressive strength of mortars in Na2SO4 solution were higher than those in water. Within 150 days of immersion, the corrosion resistance coefficient and compressive corrosion resistance coefficient of mortars increased with increasing dolomite powder dosage. The pore structure of cement-based materials became more compact with the addition of dolomite powder. Accordingly, the sulfate resistance was improved by controlling the dynamics stage due to the fact that the pore structure of cement-based materials was refined with the addition of dolomite powder. The 150-day compressive corrosion resistance coefficients of mortars with a w/b of 0.55 in the case of dolomite powder at 0 and 30 wt% replacement levels were less than 1, suggesting that long-term immersion in sulfate solution increased the deterioration rate of cement-based materials.

Reducing anionic surfactant adsorption using polyacrylate as sacrificial agent investigated by QCM-D

Surfactant losses by adsorption to rock surfaces make surfactant-based enhanced oil recovery economically less feasible. We investigated polyacrylate (PA) as a sacrificial agent in the reduction of anionic surfactant adsorption with focus on calcite surfaces by using quartz crystal microbalance with dissipation monitoring. It was found that the adsorption of the anionic surfactant alcohol alkoxy sulfate (AAS) followed a Langmuir adsorption isotherm, and the adsorbed amount reached saturation above its critical micellar concentration. Adsorption of PA was a much slower process compared to AAS adsorption. Increasing the calcium ion concentration also increased the amount of AAS adsorbed as well as the mass increase rate of PA adsorption. Experimental results combined with density functional theory calculations indicated that calcium cation bridging was important for anionic surfactant AAS and PA adsorption to calcite surfaces. To effectively reduce the amount of surfactant adsorption, it was needed to preflush with PA, rather than by a simultaneous injection. Preflushing with 30 ppm of PA gave a reduction of AAS adsorption of 30% under high salinity (HS, 31,800 ppm) conditions, compared to 8% reduction under low salinity (LS, 3180 ppm) conditions. In the absence of PA, the amount of adsorbed AAS was reduced by already 50% upon changing from HS to LS conditions. Lower calcium ion concentrations, as under LS conditions, contributed to this observation. On different mineral surfaces, PA reduced the AAS adsorption in the order of alumina > calcite > silica. These results offer important insights into mitigating surfactant adsorption using PA polyelectrolyte as sacrificial agent and contribute to improved flooding strategies with reduced surfactant loss.

Spectroscopy and Differential Emission Measure Diagnostics of a Coronal Dimming Associated with a Fast Halo CME

Abstract We study the coronal dimming caused by the fast halo CME (deprojected speed v = 1250 km s−1) associated with the C3.7 two-ribbon flare on 2012 September 27, using Hinode/EIS spectroscopy and Solar Dynamics Observatory (SDO)/AIA Differential Emission Measure (DEM) analysis. The event reveals bipolar core dimmings encompassed by hook-shaped flare ribbons located at the ends of the flare-related polarity inversion line, and marking the footpoints of the erupting filament. In coronal emission lines of log T [K] = 5.8–6.3, distinct double-component spectra indicative of the superposition of a stationary and a fast upflowing plasma component with velocities up to 130 km s−1 are observed at these regions, which were mapped by the scanning EIS slit close in time to their impulsive dimming onset. The outflowing plasma component is found to be of the same order as and even dominant over the stationary one, with electron densities in the upflowing component of 2 × 109 cm−3 at log T [K] = 6.2. The density evolution in core-dimming regions derived from SDO/AIA DEM analysis reveals impulsive reductions by 40%–50% within ≲10 minutes and remains at these reduced levels for hours. The mass-loss rate derived from the EIS spectroscopy in the dimming regions is of the same order as the mass increase rate observed in the associated white-light CME (1 × 1012 g s−1), indicating that the CME mass increase in the coronagraphic field of view results from plasma flows from below and not from material piled up ahead of the outward-moving and expanding CME front.

Hubble Space Telescope Far-UV Spectroscopy of the Short Orbital Period Recurrent Nova CI Aql: Implications for White Dwarf Mass Evolution

Abstract An Hubble Space Telescope Cosmic Object Spectrograph Far UV spectrum (1170 Å to 1800 Å) was obtained for the short orbital period recurrent novae (T Pyxidis subclass), CI Aquilae. CI Aql is the only classical Cataclysmic variable (CV) known to have two eclipses of a sensible depth per orbit cycle and also to have pre- and post-outburst light curves that are steady enough to allow estimates of mass and orbital period changes. Our far-ultraviolet (FUV) spectral analysis with model accretion disks and non-LTE high-gravity photospheres, together with the Gaia parallax, reveal that CI Aql's FUV light is dominated by an optically thick accretion disk with an accretion rate of the order of 4 × 10−8 M ☉ yr−1. Its database of light curves, radial velocity curves, and eclipse timings is among the best for any CV. Its orbit period (P), dP/dt, and reference time are rederived via a simultaneous analysis of the three data types, giving a dimensionless post-outburst dP/dt of (−2.49 ± 0.95) × 10−10. The lack of information on the loss of orbital to rotational angular momentum leads to some uncertainty in the translation of dP/dt to the white dwarf (WD) mass change rate, dM1/dt, but within the modest range of to +7.8 × 10−8 . The estimated WD mass change through outburst for CI Aql, based on simple differencing of its pre- and post-outburst orbit period, is unchanged from the previously published . At the WD's estimated mass increase rate, it will terminate as a Type Ia supernova within 10 million years.

The impact of relative humidity on the size distribution and chemical processes of major water-soluble inorganic ions in the megacity of Chongqing, China

To investigate the impacts of relative humidity (RH) on the size distribution and evolution of water-soluble inorganic ions (WSIIs) in Chongqing, China, size-resolved aerosols were collected using nine-stage viable Andersen cascade impactors bi-weekly from June 2012 to May 2014. The WSIIs (SO42−, NO3−, NH4+, K+, Na+, Cl−, Ca2+, Mg2+ and F−) were analyzed. The SO42−, NO3− and NH4+ peaks shifted from 0.43–0.65μm particles at 40–60% RH to 0.65–1.1μm particles at 70–90% RH. For K+, Na+ and Cl−, the peak concentrations were in the size range of 0.65–2.1μm and increased as the RH increased from 40 to 90%. However, the Ca2+, Mg2+ and F− peaks at all RH levels were mainly concentrated in the coarse mode, and their concentrations did not increase as regularly as those of SO42−, NO3− and NH4+. All of the results suggest that RH was likely an important factor in determining the size distributions of the WSIIs. SO42−, NO3− and NH4+ increased linearly in all size ranges as a function of RH (40–90%). Additionally, SO42− presented the highest rate of mass increase at 1.8μg/m3/10% RH in 1.1<Dp≤2.1μm particles. For NO3−, the ratio of NO3− in the WSIIs in 1.1<Dp≤2.1μm particles increased more with increasing RH than that in the other size ranges. The NO3− in 0.43<Dp≤2.1μm particles increased by approximately 8% when the RH increased from 40–60% to 60–90%. The NH4+ in 1.1<Dp≤2.1μm particles increased at the highest rate with increasing RH, and the proportion of NH4+ in the WSIIs in 0.43<Dp≤1.1μm particles was higher than that in the other size ranges. Aerosol acidity in the fine-mode particles increased with increasing RH but decreased with the increase in particle size.

Influence of Hydrogen Adsorption on Electrodeposition of Platinum from Chloro Complex Solution

Platinum (Pt) is widely used as insoluble and catalytic electrodes for electrolysis, automotive catalytic converters, and fuel cells. We have been investigating hydrogen incorporation in electrodeposited metal films and its influence on crystal structure of metals (1-3). It was reported that large amount of hydrogen (content in atomic ratio: x = H/Pt = 0.1) is incorporated in the Pt films electrodeposited from a solution including dinitrosulfatoplatinate(II) (H2Pt(NO2)2SO4, DNS) as a metal source. In this study, an electrochemical quartz crystal microbalance (EQCM) method (4) is used to examine influence of hydrogen adsorption on the electrodeposition and hydrogen incorporation into deposited films of Pt from a chloro complex solution. The current-potential and mass increase (Pt deposition rate)-potential curves in 0.024 mol dm-3 K2PtCl4solution adjusted at pH of 0.8 with HCl were measured using an EQCM system (Hokuto Denko, HQ-101D and HZ-5000). A quartz electrode coated with Au, an Ag/AgCl electrode, and a Pt wire were used as the working, reference, and counter electrodes, respectively. The hydrogen content of samples was measured by thermal desorption spectroscopy (TDS). Figure 1 shows the current density and mass increase rate versus electrode potential curves for the chloro complex solution. In the first forward potential sweep toward negative potentials of Fig. 1(a), the cathode current and deposition rate of Pt started increasing at +0.3 V vs. Ag/AgCl. Peaks for cathode current and deposition rate appeared at -0.19 V. The current efficiency was 74% at this peak. Then, as the potential was swept to lower potentials, the deposition rate and current efficiency decreased. This decrease in the current efficiency of Pt deposition is caused by hydrogen adsorption. In the return potential sweep (Fig.1 (b)), the cathode current and Pt deposition steeply increased by hydrogen desorption from the Pt surface, and the current efficiency was 113% at the potential of -0.25 V. The hydrogen content of Pt-electrodeposited Au foil (Pt: 1 μm and Au: 20 μm in thickness) increased as the deposition potential of Pt decreased from 0 to -0.3 V, and was much lower than that deposited from the DNS solution. Acknowledgements The present work was partly supported by JSPS KAKENHI (26289276). References N. Fukumuro, M. Yokota, S. Yae, H. Matsuda, Y. Fukai, J. Alloys Compd., 580, S55 (2013). N. Fukumuro, S. Kojima, M. Fujino, Y. Mizuta, T. Maruo, S. Yae, Y. Fukai, J. Alloys Compd., 645, S404 (2015). N. Hisanaga, N. Fukumuro, S. Yae, H. Matsuda, ECS Trans., 50, 77 (2013). T. Hagihara, K. Yaori, K. Iwakura, N, Fukumuro, S. Yae, Electrochim. Acta, 176, 65 (2015). Figure 1

Evaluation of the susceptibility of coal to spontaneous combustion by a TG profile subtraction method

It is imperative to have an in-depth understanding of the intrinsic reaction between coal and oxygen during low-temperature oxidation, as the reaction is the main source responsible for the self-heating and spontaneous combustion of coal. As low-temperature oxidation of coal involves a series of physical and chemical process and many parallel reactions, it is difficult to directly investigate the intrinsic reaction between coal and oxygen by conventional analytical method. Thermogravimetric analysis (TGA) was used to investigate the intrinsic reaction between coal and oxygen based on the mass change. By means of the subtraction analysis method of TGA, the TG-subtraction curves were obtained by subtracting the TG-N2 curves from the TG-air curves. The results indicate that a TG-subtraction curve can better reflect the intrinsic reaction of coal oxidation than a TG-air curve by eliminating the influence of evaporation of water and thermal decomposition of inherent oxygen-containing groups. In terms of the rate of mass increase, the intrinsic reactions can be divided into three stages: slow oxidation stage, advanced oxidation stage and rapid oxidation stage. The activation energy at each of the stages, obtained by Coats and Redfern’s model, can be used to as a technical parameter to evaluate the proneness of coal spontaneous combustion. The optimum experiment conditions were also developed to study low-temperature coal oxidation with the subtraction method of TGA.

Modeling frazil ice growth in the St. Lawrence River

The paper presents a complete energy balance model of suspended frazil ice formation in the tidal water column of the St. Lawrence River. The model estimates of suspended frazil ice concentration are compared to in situ observations of an analogue of suspended frazil ice crystals, with good results. A time series of observed acoustic backscattering from suspended frazil serves as the analogue of the suspended frazil concentration. The model of frazil ice growth is used to estimate the rate of increase in mass of the suspended frazil ice by balancing the net rate of energy exchange with the atmosphere with the observed changes in water temperature and in anchor ice thickness. The positive results are achieved despite a number of difficulties with analysis. These difficulties include the bias resulting from the inability of the sonar to detect across the complete size range of suspended ice, the unknown impacts of advection, the unknown impact of anchor ice build-up on temperature and sonar readings, and the lack of knowledge regarding the accuracy of sonar estimation of anchor ice thickness. These results highlight the promise of models, suitably applied, and sonar to quantitatively estimate suspended frazil ice concentration.

Tracking post-hibernation behavior and early migration does not reveal the expected sex-differences in a "female-migrating" bat.

Long-distance migration is a rare phenomenon in European bats. Genetic analyses and banding studies show that females can cover distances of up to 1,600 km, whereas males are sedentary or migrate only short distances. The onset of this sex-biased migration is supposed to occur shortly after rousing from hibernation and when the females are already pregnant. We therefore predicted that the sexes are exposed to different energetic pressures in early spring, and this should be reflected in their behavior and physiology. We investigated this in one of the three Central European long-distance migrants, the common noctule (Nyctalus noctula) in Southern Germany recording the first individual partial migration tracks of this species. In contrast to our predictions, we found no difference between male and female home range size, activity, habitat use or diet. Males and females emerged from hibernation in similar body condition and mass increase rate was the same in males and females. We followed the first migration steps, up to 475 km, of radio-tagged individuals from an airplane. All females, as well as some of the males, migrated away from the wintering area in the same northeasterly direction. Sex differences in long-distance migratory behavior were confirmed through stable isotope analysis of hair, which showed greater variation in females than in males. We hypothesize that both sexes faced similarly good conditions after hibernation and fattened at maximum rates, thus showing no differences in their local behavior. Interesting results that warrant further investigation are the better initial condition of the females and the highly consistent direction of the first migratory step in this population as summering habitats of the common noctule occur at a broad range in Northern Europe. Only research focused on individual strategies will allow us to fully understand the migratory behavior of European bats.

From haloes to Galaxies – I. The dynamics of the gas regulator model and the implied cosmic sSFR history

We explore the basic parameters that drive the evolution of the fundamental properties of star forming galaxies within the gas regulator model, or bathtub-model. We derive the general analytic form of the evolution of the key galaxy properties, i.e. gas mass, star formation rate (SFR), stellar mass, specific SFR, gas fraction, gas phase metallicity and stellar metallicity, without assuming that galaxies live in the equilibrium state. We find that the timescale required to reach equilibrium, tau_eq, which is determined by the product of star-formation efficiency and mass-loading factor, is the central parameter that is essentially in control of the evolution of all key galaxy properties. The scatters in most of the key scaling relations, such as the mass-SFR relation and mass-metallicity relation, are primarily governed by tau_eq. Most strikingly, the predicted sSFR evolution is controlled solely by tau_eq (apart from the cosmic time). Although the precise evolution of the sSFR depends on tau_eq, the sSFR history is largely insensitive to different values of tau_eq. The difference between the minimum and maximum sSFR at any epoch is less than a factor of four. The shape of the predicted sSFR history simply mimics that of the specific mass increase rate of the dark matter halos (sMIR_DM) with the typical value of the sSFR around 2*sMIR_DM, in good agreement with the predictions from typical Semi-Analytic Models (SAMs), but both are fundamentally different from the observed sSFR history. This clearly implies that some key process is missing in both typical SAMs and gas regulator model, and we hint at some possible culprit. We emphasize the critical role of tau_eq in controlling the evolution of the galaxy population, especially for gas rich low mass galaxies that are very unlikely to live around the equilibrium state at any epoch and this has been largely ignored in many similar studies.

Wetting of Carbonaceous Fuel Particles by Molten Alkali Metal Hydroxide and Carbonate Electrolytes

The method of capillary rise in a random bed of particles, as measured by the rate of mass increase of packed beds of sample particles, was applied to measurements of the relative wetting characteristics of selected particulate carbonaceous fuels by different molten electrolytes of general interest in electrochemical energy applications. In particular, a series of activated chars as well as Pittsburgh (#8) and Beulah-Zap lignite coal samples (both as-received and pyrolyzed) were investigated. It was found that the wetting coefficient (k = cos θ) of the molten electrolytes (NaOH, KOH, a binary NaOH/KOH eutectic mixture, and a ternary alkali metal carbonate eutectic) on an activated char all increased with the temperature in an approximately linear fashion over the limited temperature ranges investigated. It was also found that the wetting coefficient increased with decreasing particle size. This was observed for both the activated chars and the coal samples. In addition, it was found that pyrolysis significantly improved the wetting of both coals investigated. In the current work, this was attributed to increasing the concentration of mineral matter in the resultant pyrolyzed samples at the liquid−solid interface.

Study on Chemical Plating and Shielding Effectiveness for Electromagnetic Shielding Fabric

For the purpose of investigating the influence of different process condition on alkali reduce rate and mass increase rate, the techniques of polyester fiber pretreatment, electroless copper plating, and electroless silver plating were carefully analyzed and compared. It was found that the best coursing condition was: 5.5 mol/L concentration, 65°C temperature, 30 minutes reaction time, 1:200 bath ratio. Under these conditions, the alkali reduction rate was 11.38%. As for copper plating liquid concentration of 0.08 mol/L, pH value 9.5, 80°C temperature, liquid silver plated concentration 0.02 mol/L, the coating weight gain rate was 52.1%. Microcosmic morphology on coating surface and surface resistance test show that the fabric was evenly coated with Cu, Ag, metal ions, which resulting in excellent electric conductivity and good electromagnetic shielding performance.

The impact of relative humidity on aerosol composition and evolution processes during wintertime in Beijing, China

Non-refractory submicron aerosol (NR-PM1) species measured by an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) along with collocated gaseous species are used to investigate the impacts of relative humidity (RH) on aerosol composition and evolution processes during wintertime in Beijing, China. Aerosol species exhibit strong, yet different RH dependence between low and high RH levels. At low RH levels (<50%), all aerosol species increase linearly as a function of RH, among which organics present the largest mass increase rate at 11.4 μg m−3/10% RH. Because the particle liquid water predicted by E-AIM model is very low and the temperature is relatively constant, the enhancement of aerosol species is primarily due to the decrease of wind speed. While the rates of increase for most aerosol species are reduced at high RH levels (>50%), sulfate presents an even faster increasing rate, indicating the significant impact of liquid water on sulfate production. The RH dependence of organic aerosol (OA) components is also quite different. Among OA components, coal combustion OA (CCOA) presents the largest enhancement in both mass concentration and contribution as a function of RH. Our results elucidate the important roles of liquid water in aerosol processing at elevated RH levels, in particular affecting sulfate and CCOA via aqueous-phase reaction and gas-particle partitioning associated with water uptake, respectively. It is estimated that aqueous-phase processing can contribute more than 50% of secondary inorganic species production along with an increase of aerosol particle acidity during the fog periods. However, it appears not to significantly enhance secondary organic aerosol (SOA) formation and the oxidation degree of OA.

Increased mass over the Tibetan Plateau: From lakes or glaciers?

AbstractThe mass balance in the Inner Tibet Plateau (ITP) derived from the Gravity Recovery and Climate Experiment (GRACE) showed a positive rate that was attributed to the glacier mass gain, whereas glaciers in the region, from other field‐based studies, showed an overall mass loss. In this study, we examine lake's water level and mass changes in the Tibetan Plateau (TP) and suggest that the increased mass measured by GRACE was predominately due to the increased water mass in lakes. For the 200 lakes in the TP with 4 to 7 years of ICESat data available, the mean lake level and total mass change rates were +0.14 m/yr and +4.95 Gt/yr, respectively. Compared those in the TP, 118 lakes in the ITP showed higher change rates (+0.20 m/yr and +4.28 Gt/yr), accounting for 59% area and 86% mass increase of the 200 lakes. The lake's mass increase rate in the ITP explains the 61% increased mass (~7 Gt/yr) derived from GRACE [Jacob et al., 2012], while it only accounts for 53% of the total lake area in the ITP.

Extinction of Wood Fire - The mass increase rate and the extinction time -

Extinction of Wood Fire - The mass increase rate and the extinction time -

Thermal and spectral behavior of (Y,Eu)VO4 powder

Thermal analysis of YxEu1−xVO4 powder (used as “phosphor” coating for a high pressure mercury lamp) was done under a non-isothermal linear regime, both in a dynamic air regime and in a nitrogen atmosphere. The heating in air atmosphere gave on TG curve small rate of mass increase due to oxygenation and two endothermic effects are observed on DTA and DSC curves. By contrary, in nitrogen atmosphere a continuous stepped mass loss of powder (around 0.65 %), is recorded in the range of temperatures from room temperatures to 1,200 °C, and only one endothermic effect, to eliminate the gases accumulated on the crystallite surface. The powder was heated for 3 h in a Nabertherm furnace at 350, 800, and 1,100 °C using quite similar rate for heating program followed by a furnace cooling to room temperature. XRD and FTIR analyses showed the sample purification by thermal treatment and a very small increase of nanocrystallite sizes. The time evolution of the optical emission spectra in the range from 186.2 to 877.47 nm were recorded for different lamp powers in two different situations: with the outer bulb coated with YxEu1−xVO4 type “phosphor”, and without it. We observed that UV-Hg lines are absorbed by YxEu1−xVO4 type “phosphor” with different percents (100 % for 253.73 nm, 95 % for 312.65 nm, and 33 % for 365.12 nm) but the heating of the powder do not influence the UV-absorption properties of the powder.

The uptake by Escherichia coli and growth inhibitory properties of benzyl alcohol and phenethyl alcohol.

Abstract The effects of benzyl alcohol (0–4 mg/ml) and phenethyl alcohol (0–2.5 mg/ml) on the rate of mass increase in cultures of E. coli were studied by absorbance measurements. Growth rate constants in the partially inhibited cultures were calculated. With both agents the growth rate was reduced on increasing the alcohol concentration, the extent of this reduction becoming progressively larger for equal increments in concentration. The inhibition of growth was shown to be reversible and to result from a uniform inhibition of the individual cells. The overall cellular uptake of benzyl alcohol was approximately the same as that of phenethyl alcohol. With both agents the uptake was proportional to the concentration of alcohol remaining in the medium and was independent of contact time within the range of 10–90 min. Phenethyl alcohol is, however, more effective than benzyl alcohol in inhibiting growth. This is attributed to a greater uptake of the former by the cellular membrane.