Top PDF The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of <i>β</i>-caryophyllene secondary organic aerosol

The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of <i>β</i>-caryophyllene secondary organic aerosol

The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of <i>β</i>-caryophyllene secondary organic aerosol

standard (BOC Special Gases, UK); (ii) analysis of gas standards generated from per- meation tubes (Eco-Scientific Ltd, UK and Vici Inc., US) using a commercial calibration and humidification unit (Kintec, model 491) and (iii) analysis of 10 l Teflon sample bags (SKC Inc. US) following liquid injection of the target VOC/OVOC into a nitrogen ma- trix. Mass spectrometric data was recorded by the CIR-TOF-MS over the range 0 and

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The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic  properties of β-caryophyllene secondary organic aerosol

The effect of photochemical ageing and initial precursor concentration on the composition and hygroscopic properties of β-caryophyllene secondary organic aerosol

The extracts obtained from the filters were directly injected into the ion trap mass spectrometer without separation using a syringe pump at 240 µlpm, to obtain a molar mass distribu- tion. This allows a quick visual comparison to be made be- tween SOA of different degrees of ageing. Figure 3 shows the negative ion m/z distribution of the lower and higher initial concentration samples at 2 h and 6 h. Prior to the ex- periments presented here, 2 α-pinene experiments were car- ried out under identical conditions (30 ppbV VOC) but on consecutive days to test variability. Filter samples were col- lected at the same point in each experiment and the sam- ples were analysed using LC-MS. Eight α-pinene SOA peaks were chosen (including cis-pinonic acid and 3-methyl-1,2,3- butanetricarboxylic acid – MBTCA) and the peak areas were determined. The ratio of peak areas between the two sam- ples was calculated and gave an average value of 1.17. This indicates that any variability seen in the mass spectra for the β-caryophyllene analysis is a result of aerosol ageing and not a product of experiments being conducted on different days. It is clear from Fig. 3 that photochemical ageing changes the SOA composition. After two hours of ageing the SOA composition is relatively simple and is dominated by peaks from m/z 230–340. As the photochemical ageing proceeds, the condensed phase mass spectra become increasingly com- plex. This can be seen over the range m/z 200–290, where rather than comprising single peaks 14–16 m/z apart, as was seen at t = 2 h, the mass spectra at t = 6 h starts to fill up at every odd mass. There is also a change in the molar mass distribution with time, with an increase in smaller molecules
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Formation and chemical aging of secondary organic aerosol during the β-caryophyllene oxidation

Formation and chemical aging of secondary organic aerosol during the β-caryophyllene oxidation

Alfarra, M. R., Hamilton, J. F., Wyche, K. P., Good, N., Ward, M. W., Carr, T., Barley, M. H., Monks, P. S., Jenkin, M. E., Lewis, A. C., and McFiggans, G. B.: The effect of photochem- ical ageing and initial precursor concentration on the composition and hygroscopic proper- ties of β-caryophyllene secondary organic aerosol, Atmos. Chem. Phys., 12, 6417–6436,

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In-cloud processes of methacrolein under simulated conditions – Part 3: Hygroscopic and volatility properties of the formed secondary organic aerosol

In-cloud processes of methacrolein under simulated conditions – Part 3: Hygroscopic and volatility properties of the formed secondary organic aerosol

lization of solutions after aqueous-phase photooxidation of methacrolein is, hence, more volatile than the ones formed through gas-phase photooxidation of terpenes after a few hours of reactions. This difference can be explained by i) the difference of the chemical structure of the precursor VOC and ii) the different formation pathways of the SOA. Age- ing has a significant effect on the volatilization properties, in agreement with ageing of some gas-phase terpene pho- tooxidation products (Kalberer et al., 2004). Oligomeres have been observed to be formed during aqueous-phase gly- coaldehyde oxidation (Perri et al., 2009). Oligomerization is suspected to form 100 ◦ C-refractory compounds which can explain our results. We observed that the oligomerization process is in competition with the formation of other non- oligomerizing compounds, detected as unidentified higher molecular weight multifunctional products by El Haddad et al. (2009). The same volatility properties characterize the SOA formed from the nebulization of the same solutions where NaCl was added, indicating a good reproducibility of our results. The HGF of the SOA produced from the nebulization of solutions after liquid-phase photooxidation of methacrolein is 1.34–1.43, which is slightly higher than the HGF of SOA formed from the gas-phase photooxida- tion of terpenes. This result can be due to the presence of hygroscopic products such as oxalic acid or dihydrox- ymethacrylic acid (El Haddad et al., 2009), and it confirms the volatility results. Before Oligomerization took place (at t=5 h), we observed that the hygroscopicity of the 250 ◦ C- refractory fraction was higher than the hygroscocpicity of the volatile fraction (1.52 vs. 1.41, respectively). Meyer et
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The Existence Of Leading Islands Securing And The Border Areas Unitary State Of Indonesia An Analysis In Law Perspective

The Existence Of Leading Islands Securing And The Border Areas Unitary State Of Indonesia An Analysis In Law Perspective

Based on the objectives to be achieved and problems that have been formulated, the method used is juridical- sociological. The juridical approach is intended to explore and study the legislation as a basis for a research, while the sociological approach is intended to explore the factors and impacts incurred from the occurrence of border-area dispute and solution by the government. The specifications of this research are normative law called also as doctrinal research. A site was chosen by researcher to conduct a research is a government agency that includes the Navy (Department of Hydro-Oceanographic) related to the sea boundaries of the Republic of Indonesia and neighboring countries, local governments, especially in the leading islands border to the Republic of Indonesia related to culture, security, politics and thinking about the area/island they occupy, as a part of the Unitary of the Republic of Indonesia. The population is all research objects to be researched. In this research, the population is Navy and the relevant agencies involved in the security of sea area. The samples were chosen to be a material of research is the bearer of the security function in marine areas through the random system and interviews with relevant parties, such as Bakorkamla and community.
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White and gray solidification of the Fe-C eutectic

White and gray solidification of the Fe-C eutectic

The research indicated that total number of nucleation was given by N A ( T ) n where T is the undercooling with respect to the equilibrium temperature of the phase transformation, A and n are constants reflecting the inoculation treatment. The nucleation rate is expressed as eq. (6), and the number of nuclei appearing in liquid from calculation time t to t+dt can be calculated by considering the available liquid volume of nucleation with eq. (7):
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Evaluating the influence of selected parameters on sensitivity of a numerical model of solidification

Evaluating the influence of selected parameters on sensitivity of a numerical model of solidification

Sensitivity analysis was conducted each time for the model described in Section 3, for which it was assumed that the parameters vary in ranges given in Table 1. Table 2 lists parameters influence of which was not taken into consideration in sensitivity analysis. According to the fact that these parameters are connected with the phase change diagram, they cannot be changed freely and independently from one another. Additionally, in Table 2 physical parameters of the mould are included. Table 2.

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The Effects of Gender Segregation at the Occupation, Industry, Establishment, and Job-Cell Levels on the Male-Female Wage Gap

The Effects of Gender Segregation at the Occupation, Industry, Establishment, and Job-Cell Levels on the Male-Female Wage Gap

in four dimensions: occupation, industry, firm, and job cell. One of the contributions of this paper is the estimation of these effects including fixed effects to control for unobserved, time-invariant characteristics of workers, firms, and worker-firm matches. The workers’ fixed effects capture unobserved heterogeneity in their abilities/skills, motivation, preferences, and personality traits, all of which affect wages and can be correlated with the allocation of workers across the four dimensions of interest. If females’ tastes are such that they are prepared to trade more easily the pecuniary for non-pecuniary aspects of the jobs, one should expect to observe a higher concentration of women in occupations, industries, establishment, and job cells that pay lower wages. It could also be that less productively able men and women sort (or are sorted) into predominantly female jobs that command lower wages. In both cases, the estimates of the effects of female segregation on wages will be misleading if worker-specific fixed effects are not part of the model.
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The application of optical measurements for the determination of accuracy of gear wheels casts manufactured in the RT/RP process

The application of optical measurements for the determination of accuracy of gear wheels casts manufactured in the RT/RP process

The article discusses the possibilities of using optical measurements for defining the geometric accuracy of gear wheels casts manufactured in the rapid prototyping process. The tested gear wheel prototype was cast using an aluminum alloy. The casting mould was made by means of the three-dimensional print method (3DP) with the use of a Z510 Spectrum device. The aim of the tests was to determine the geometric accuracy of the cast made by the ZCast technology in the rapid prototyping process. The tests were conducted with the use of the coordinate optical measuring method and a GOM measuring device. The prototype measurements were made in the scanning mode. The results of the measurements, saved in the STL format with the use of the scanning device software, were compared with the gear wheel 3D-CAD nominal model. The measurements enabled the determination of the real accuracy of prototypes manufactured in casting moulds by means of the ZCast technology. The selection of the measuring method was also analyzed in terms of measurement accuracy and the RP technology precision.
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Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Operating characteristics of turbine mixers based on the analysis of power demand of the mixer’s drive

Power demand of a mixing system in a roller mixer is shown in Fig 1. During the mixing cycle the power demand increases with an increase in the surface area of grains covered with clay-water slurry, accompanied by an increase in the sand mix resistance. The mixing cycle involves: I- idle run, II- charging of mix components; III- homogenisation; IV- water dosing; V- mixing of wet mix, VI- emptying the mixer.

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Influence of vibrations during crystallization on mechanical properties and porosity of AlSi13Cu2 alloy

Influence of vibrations during crystallization on mechanical properties and porosity of AlSi13Cu2 alloy

Today’s industry aims at such situation, where number of defective products, so called defects shall approach to zero. Therefore, one introduces a various changes in technology of production, introduces improvements which would help in accomplishment of this objective. Another important factor is introduction of different type of testing, which shall help in assessment which factor has significant effect on quantity of rejects, and which one could be neglected. Existence of casting rejects is unavoidable; therefore a new ideas, technologies and innovations are necessary in the entire widely understood foundry branch, in order to minimize such adverse effect. Performance of tests aimed at unequivocal determination of an effect of vibrations during crystallization on mechanical properties and porosity of the AlSi13Cu2 alloy was the objective of the present work. To do this, there were produced 36 castings from AlSi13Cu2 alloy. All the castings underwent machining operations. Half of the casting was destined to strength tests, the other half served to determination of an effect of vibrations on porosity of the alloy. The specimens were divided into 12 groups, depending on amplitude of vibrations and tilt angle of metal mould during pouring operation.
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Determinants and Consequences of   the Website Perceived Value

Determinants and Consequences of the Website Perceived Value

To the commercial website, telepresence is the equivalent of general and internal variables. According to Sheridan (1992), Steuer (1995), Biocca (1997), Lombard and Ditton (1997) and Shith (1998), the telepresence concept is used to describe the gratifying sense to be present in a mediated environment which appears as it naturally was. Hoffman and Novak (1996), Novak, Hoffman and Yung (1999) assert that telepresence is the perception that the virtual environment, with which the user is in interaction, is more real and dominant than the physical environment. Volle (2000), as for him, highlights that the principle challenges landed by the virtual atmosphere consist to maintain a high attention and a fluidity sensation that captures the visitor. Thus, a site with captivating content is the one that allows visitors to live a telepresence experience. During this research, we consider the steuer (1992)’s conceptualization of telepresence envisioning this later as “The extent to which one feels present in the mediated environment rather than in the immediate physical environment”. In other words, telepresence refers to the mediated perception of an environment that can be a spatially distant, real environment, or a virtual world.
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The Influence of Small Amounts of Aluminium on the Spheroidization of Cast Iron with Cerium Mischmetal

The Influence of Small Amounts of Aluminium on the Spheroidization of Cast Iron with Cerium Mischmetal

The work was aimed to determine the influence of aluminium in the amount from about 0.6% to about 2.8% on the structure of cast iron treated with cerium mischmetal and subjected to graphitizing modification with 75% ferrosilicon. Four experimental melts were held during the investigation. The charge was composed of the specially prepared grey iron, containing the basic elements within the presumed limits. While determining the desirable quantity of carbon in the charge cast iron, two contradicting conditions were taken into account, i.e. that the purpose is to achieve the nodular cast iron (which means that the relatively large carbon amount would be demanded) and that introducing aluminium to the melt results in the decreased solubility of carbon in cast steel. Taking this into account, it was stated that the quantity of carbon in the charge cast iron should be maintained within the range of 3.2÷3.4%. It has been assumed that the silicon content in the charge material should fall within 0.7÷1.0%, as it was during the former investigations. Manganese content was restricted to 0.1% maximally in order to achieve the desired structure with ferrite fraction as high as possible. It has been also assumed that the content of both sulphur and phosphor should be at the possible lowest level.
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Selection of the temperature of casting the bronzes to plaster moulds

Selection of the temperature of casting the bronzes to plaster moulds

dependence from the temperature of casting the bronze to the mould on Figure 6. From the introduced cross - section of casts from the probe TDAg, it results that it together with considerably grows up the depth of the contraction cavity with the growth of the temperature of casting, and what joins with this executed along its axis the volumetric contraction grows up, especially bronze B555 (Fig. 5a and 6). The bronze B10 is characterizes considerably smaller volumetric contraction (Fig. 5b and 6), however overheated 1180 °C above and cast to the hot plaster mould, in the conditions of the atmospheric pressure, it undergoes strong gassing with what considerable decrease of the depth of the contraction cavity joins (Fig. 5b 1200 ° C and Fig . 6). Zinc as high active metal in the relation of oxygen influences the lower- ing of the content of gases dissolved in the bronze B555. Consid- erably larger content Zn in the chemical composition of the bronze B555 (approx. 5%), in the comparison with the bronze B10 (to 0.5 %), it favours creation on the surface of the solidifica- tion bronze of the layer of oxides Zn and Cu, in the composition natural slags about the smaller mass density from the liquid bronze, making difficult chemical adsorption and dissolving the hydrogen and oxygen in the liquid bronze. Bronze B10 including first of all the admixture approx. 10% Sn, element of little active in the relation to oxygen, it absorbs from surroundings highly both the hydrogen as and the oxygen, what it brings in the conse- quence, together with the growth of the temperature of casting, to gassing the bronze.
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Modelling the formation and composition of secondary organic aerosol from α- and β-pinene ozonolysis using MCM v3

Modelling the formation and composition of secondary organic aerosol from α- and β-pinene ozonolysis using MCM v3

Abstract. The formation and detailed composition of sec- ondary organic aerosol (SOA) from the gas phase ozonoly- sis of α- and β-pinene has been simulated using the Mas- ter Chemical Mechanism version 3 (MCM v3), coupled with a representation of gas-to-aerosol transfer of semivolatile and involatile oxygenated products. A kinetics represen- tation, based on equilibrium absorptive partitioning of ca. 200 semivolatile products, was found to provide an accept- able description of the final mass concentrations observed in a number of reported laboratory and chamber experiments, provided partitioning coefficients were increased by about two orders of magnitude over those defined on the basis of estimated vapour pressures. This adjustment is believed to be due, at least partially, to the effect of condensed phase as- sociation reactions of the partitioning products. Even with this adjustment, the simulated initial formation of SOA was delayed relative to that observed, implying the requirement for the formation of species of much lower volatility to ini- tiate SOA formation. The inclusion of a simplified repre- sentation of the formation and gas-to-aerosol transfer of in- volatile dimers of 22 bi- and multifunctional carboxylic acids (in addition to the absorptive partitioning mechanism) al- lowed a much improved description of SOA formation for a wide range of conditions. The simulated SOA composi- tion recreates certain features of the product distributions ob- served in a number of experimental studies, but implies an important role for multifunctional products containing hy- droperoxy groups (i.e. hydroperoxides). This is particularly the case for experiments in which 2-butanol is used to scav- enge OH radicals, because [HO 2 ]/[RO 2 ] ratios are elevated
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Observation of viscosity transition in <i>α</i>-pinene secondary organic aerosol

Observation of viscosity transition in <i>α</i>-pinene secondary organic aerosol

very low depolarization ratios. SIMONE-Junior is based on the design of the first SIMONE instrument (Schnaiter et al., 2012), which is installed at the cloud chamber facil- ity Aerosol Interactions and Dynamics in the Atmosphere (AIDA) of the Karlsruhe Institute of Technology, with few improvements that have been implemented to attain the sen- sitivity and stability requirements that were identified in the simulations. SIMONE-Junior uses a continuous wave (cw) laser (Coherent 552 nm OBIS laser, 20 mW) to create a po- larized and collimated light beam that is directed horizon- tally across the chamber (Fig. 3). The incident linear polar- ization state of the laser beam can be aligned either parallel or perpendicular to the scattering plane by a liquid crystal polarization rotator. Moreover, in contrast to the AIDA SI- MONE, a liquid crystal variable retarder, able to be operated as a quarter-wave plate, was introduced to the system to allow generation of circularly polarized light. The orientation of the circular depolarization can be changed from right handed to left handed, although in this study we used only right-handed circular incident polarization.
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Distributions of grain parameters on the surface of aircraft engine turbine blades

Distributions of grain parameters on the surface of aircraft engine turbine blades

In the quality assurance system for components cast using the lost wax method, the object of evaluation is the grain size on the surface of the casting. This paper describes a new method for evaluating the primary grain parameters on the surface of aircraft engine turbine blades. Effectiveness of the method has been tested on two macrostructures distinguished by a high degree of diversity in the grain size. The grounds for evaluating the grain parameters consist of geometric measurement of the turbine blade using a laser profilometer and of approximation of the measurement results using a polynomial of a proper degree. The so obtained analytical non-planar surface serves as a reference point for an assessment of the parameters of grains observed on the real blade surface of a variable curvature. The aspects subjected to evaluation included: the grain areas, shape and elongation coefficients of grains on a non-planar surface of the blade airfoil, using measurements taken on a perpendicular projection by means of a stereoscopic microscope and image analysis methods, and by making calculations using the Mathematica ® package.
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Particle mass yield from <i>&beta;</i>-caryophyllene ozonolysis

Particle mass yield from <i>&beta;</i>-caryophyllene ozonolysis

The good agreement between the SMPS and AMS distributions suggests that, within detection limits, ρ eff does not vary with diameter. The integrated area under the distri- butions represents the total particle mass concentration. Figure S2 shows the scatter plot of the total mass concentrations obtained from the AMS measurements against the SMPS-derived concentrations. The slope of 0.99 ± 0.02 indicates that an AMS col-

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Criterion for selection the optimal physical and chemical properties of cobalt aluminate powder used in investment casting process

Criterion for selection the optimal physical and chemical properties of cobalt aluminate powder used in investment casting process

important factor, which influences the grain size and the quality of the casting is the amount of modifier introduced into the mould. The amount of cobalt aluminate in the primary slurry is highly variable, (ranging from 1 to 10% or higher) and depends on the specification requirements, the alloy being casted, the section thickness, and other factors [9-11]. On the grounds of the obtained results it was found that the optimal concentration of cobalt aluminate powder in ceramic mould to produce casting elements made from Inconel 713C superalloy is about 5-6%mass, however in case of S6K - 2%mass. The higher concentration of modifier does not change the grain size significantly and does not improve mechanical properties of castings. So the next step in the study is to define what chemical and physical properties should cobalt aluminate characterize in order to archive the best nucleating effect.
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A Method To Find The Area Of Sector Without The Usage Of Angle Made By The Chord

A Method To Find The Area Of Sector Without The Usage Of Angle Made By The Chord

As we know that to find the area of sector the angle made by the chord (that is chord which divides the circle) is required. But in the below method we find the ratio of the segments of the circle. Thus by relating the area of segment to the area of sector the area of sector could be found. The ratio of area of segments is related to tangents that are drawn through diameter on either side.

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