Dry Plate Research Articles

Dry deposition of metal elements on surrogate surfaces in the ambient air of central Taiwan

Different surrogate surface were used to measure the atmospheric dry deposition flux of total‐particle mass and metals. Three different surrogate surface (overhead projection, T60A20 and Teflon) and two absorbent grease (Apenzion L grease and silicone grease) were compared and investigated. The results of this study indicated that using the Teflon filter coated with the silicone grease yielded the minimum background interference and high reproducibility for metal dry deposition analysis. Dry deposition and particle concentration were sampled simultaneously among three sampling sites (THU, JES and SES) with several dry deposition plates and TSP (total suspended particle) samplers from October 1994 to December 1995 at the central Taiwan. Six individual metals (Ca, Fe, Zn, Pb, Cu and Cd) were analyzed primarily with an AA‐680/G flame atomic absorption spectrophotometer. The results showed that the highest dry deposition flux, concentration of total particle‐mass and metals occurred in the SES sampling site which had the highest mean wind speed. In general, the crustal metals (Fe, Ca) had higher dry deposition velocities, while the anthropogenic metals (Zn, Pb, Cu, Cd) had lower dry deposition velocities for all three sampling sites. The mean dry deposition velocities of total particle‐mass. Fe and Ca were 9.32, 1.93 and 1.67 cm/sec, respectively. The mean dry deposition velocities of Zn, Pb, Cu and Cd were 0.51, 0.32, 0.11 and 0.26 cm/sec, separately. The results also indicated that the deposition velocities were overestimated for mass, Fe and Ca during high wind speed for these three sampling sites compared to previous studies. A suitable sampling device to collect coarse particles is needed to verified this result. In addition, re‐suspension phenomena are significant for these three sampling sites.

Convection sous-vestimentaire. Analyse dimensionnelle et mesure des flux échangés

This article presents an experimental study that quantifies heat and mass transfers between the skin and a fabric layer. The experiment is carried out with a sponge plate heated to skin temperature, about 35°C, and saturated in moisture. Analysis by holographic interferometry provides the determination of the convective heat fluxes. Radiative flows are calculated by the radiosity method. We show the influence of the underclothing air layer, and that of the fabric using different textiles. The radiative properties also modify the underwear exchanges. The influence of mass transfer on convective phenomena was studied by comparison with a dry plate. The results that are obtained, under the form of heat fluxes, are analysed. They can be used to create a data base to check the validation of models treating heat exchanges between skin and clothes.

Role of water adsorption and salt content in atmospheric corrosion products of steel

The corrosion products formed as a new phase in a metal-atmosphere system influence atmospheric corrosion mechanisms, particularly over a long term. Water adsorption in corrosion products is very important, because it determines the time during which corrosion occurs at metal-corrosion products interface. Adsorption isotherms of the corrosion products formed on steel exposed in a coastal and a rural atmospheres were obtained. The chloride, sulfate and bicarbonate concentrations in these products were also determined. A polymolecular adsorption mechanism was determined for corrosion products formed in a coastal environment, while a monomolecular adsorption takes place in corrosion products formed in a rural one. A notable difference between chloride concentration in corrosion products and chloride deposition rate determined by the dry plate method was determined. This situation was not the same in the case of sulfate ions. It means that corrosion takes place under very variable concentrations of chloride ions and in the presence of less variable concentrations of sulfate ions.

An Improved Method for Steel-Facing Copper Etching Plates

The number of prints that can be made from acid or dry point etched copper plates can be substantially increased by electrodeposition of iron onto the surface of the plate. This process is traditionally, but incorrectly, known as steel facing. Using the Electroetch processor at 2 volts and with about 50 gm/l of aqueous sal ammoniac instead of at 6 volts with 225 gm/l gives excellent coating without the need for the operator having special skills.

Particle-bound PAH content in ambient air

Ambient air samples from a traffic intersection, an urban site and a petrochemical-industrial site (PCI) were collected by using several dry deposition plates, two Microorifice uniform deposited impactors (MOUDIs), one Noll Rotary Impactor (NRI) and several PS-1 (General Metal Work) samplers from March 1994 to June 1995 in southern Taiwan, to characterize the atmospheric particle-bound PAH content of these three areas. Twenty-one individual polycyclic aromatic hydrocarbons (PAHs) were analyzed primarily by using a gas chromatograph/mass spectrometer (GC/MS). In general, the sub-micron particles have a higher PAH content. This is due to the fact that soot from combustion sources consists primarily of fine particles and has a high PAH content. In addition, a smaller particle has a higher specific surface area and therefore may contain more organic carbon, which allows for more PAH adsorption. For a particle size range between 0.31 and 3.2 μm, both Urban/Traffic and PCI/Traffic ratios of particle-bound total-PAH content have the lowest values, ranging from 0.25 to 0.28 (mean = 0.26) and from 0.07 to 0.13 (mean = 0.10), respectively. This indicates that, during the accumulation process, the PAH mass shifted from a particle phase to a gas phase, or the particles aggregated with lower PAH-content particles, resulting in a reduction in particle-bound PAH content. By using the particle size distribution data, the dry deposition model in this study can provide a good prediction for the PAH content of dry deposition materials. In general, lower molecular weight PAHs had a larger fraction of dry deposition flux contributed by the gas phase; for 2-ring PAH (50.4, 46.3 and 28.4%), 3-ring PAHs (15.2, 15.4 and 11.7%) and 4-ring PAHs (13.0, 3.60 and 5.01%) for the traffic intersection, urban and PCI sites, respectively. For higher molecular weight PAHs—5-ring, 6-ring and 7-ring PAHs—their cumulation fraction (F%) of dry deposition flux contributed by the gas phase was lower than 3.26%. At the traffic intersection, urban and PCI sites, the mass median diameter of dry deposition materials (MMD F) of individual PAHs was between 25.3 and 49.6 μm, between 27.6 and 43.9 μm, and between 19.1 and 41.9 μm, respectively. This is due to the fact that PAH dry-deposition primarily resulted from gravitational settling of the coarse particulates (> 10 μm).

Bulging Modes of Circular Bottom Plates in Rigid Cylindrical Containers Filled with a Liquid

In this article the free vibrations of the bottom plate of an otherwise rigid circular cylindrical tank filled with liquid are studied, considering only the bulging modes (when the amplitude of the plate displacement is predominant with respect to that of the free surface). The tank axis is vertical, thus the free liquid surface is orthogonal to the tank axis. The liquid is assumed to be inviscid, and the contribution of the free surface waves to the dynamic pressure on the free liquid surface is neglected. Wet and dry mode shapes of the plate are assumed to be the same, so that the natural frequencies are obtained by using the nondimensionalized added virtual mass incremental (NA VMI) factors and the modal properties of dry plates. This simplifies computations compared to other existing theoretical approaches. NAVMI factors express the nondimensionalized ratio between the reference kinetic energy of the liquid and that of the plate and have the advantage that, due to their nondimensional form, they can be computed once and for all. Numerical results for simply supported and clamped bottom plates, as well as for supported plates with an elastic moment edge constraint are given. For more accurate results, and to exceed the limits of the assumed modes approach, the Rayleigh-Ritz method is applied and results are compared to those obtained by using the NAVMI factors and other existing methods in the literature.

Bulging Modes of Circular Bottom Plates in Rigid Cylindrical Containers Filled with a Liquid

In this article the free vibrations of the bottom plate of an otherwise rigid circular cylindrical tank filled with liquid are studied, considering only the bulging modes (when the amplitude of the plate displacement is predominant with respect to that of the free surface). The tank axis is vertical, thus the free liquid surface is orthogonal to the tank axis. The liquid is assumed to be inviscid, and the contribution of the free surface waves to the dynamic pressure on the free liquid surface is neglected. Wet and dry mode shapes of the plate are assumed to be the same, so that the natural frequencies are obtained by using the nondimensionalized added virtual mass incremental (NA VMI) factors and the modal properties of dry plates. This simplifies computations compared to other existing theoretical approaches. NAVMI factors express the nondimensionalized ratio between the reference kinetic energy of the liquid and that of the plate and have the advantage that, due to their nondimensional form, they can be computed once and for all. Numerical results for simply supported and clamped bottom plates, as well as for supported plates with an elastic moment edge constraint are given. For more accurate results, and to exceed the limits of the assumed modes approach, the Rayleigh-Ritz method is applied and results are compared to those obtained by using the NAVMI factors and other existing methods in the literature.

Dry Deposition of Polycyclic Aromatic Hydrocarbons in Ambient Air

Dry deposition and air sampling were undertaken, simultaneously, in the ambient air of an urban site and a petrochemical-industry (PCI) plant by using several dry deposition plates and PS-1 samplers from January to May 1994 in southern Taiwan. The dry deposition plate with a smooth surface was always pointed into the wind. Twenty-one polycyclic aromatic hydrocarbons (PAHs) were analyzed by a gas chromatography/mass spectrometer (GC/MSD). The dry deposition flux of total-PAHs in urban and PCI sites averaged 166 and 211 μg/m 2s˙d, respectively. In general, the PAH dry deposition flux increased with increases in the PAH concentration in the ambient air. The PAH pattern of dry deposition flux in both urban and PCI sites were similar to the pattern measured by the filter of the PS-1 sampler and completely different from the PAH pattern in the gas phase. The higher molecular weight PAHs have higher dry deposition velocities. This is due to the fact that higher molecular weight PAHs primarily associated with the particle phase are deposited mostly by gravitational settling, while the gas phase PAHs are deposited mainly by diffusion. The dry deposition velocities due to gravitational settling are much higher than those due to diffusion. When the dry-deposition-velocity ranges of gas phase PAHs were between 0.001 and 0.010 cm/s, only the lower molecular-weight PAHs—Nap and AcPy—had a significant fraction of dry deposition flux contributed by the gas phase. All the remaining higher molecular-weight PAHs had more than 94.5% of their dry deposition flux resulting from the particle phase. This is due to the fact that higher molecular weight PAHs have a greater fraction in the particle phase and the dry deposition velocities of particulates are much higher than those of the gas phase.

Dry deposition velocities of polycyclic aromatic hydrocarbons in the ambient air of traffic intersections

Abstract Dry deposition and air sampling were undertaken simultaneously at two traffic intersections (TA and TB sites) with several dry deposition plates and PS‐1 samplers from August to December 1995 in southern Taiwan. In addition, samples in a lane (L) and a residence (R) sites were also determined and compared. Twenty‐one individual polycyclic aromatic hydrocarbons (PAHs) were analyzed primarily with a gas chromatographyVmass spectrometer (GC/MS). At the traffic intersections, the dry deposition velocities of total‐PAHs averaged 0.38 and 0.23 cm sec‐1 in the day‐time and at night‐time, respectively. This result shows that, in the ambient of traffic intersections, significant fraction of PAH dry deposition are contributed by the road dust resuspension caused by traveling vehicles. In general, the lower molecular weight (LMW) PAHs, being primarily in the gas phase, have lower dry deposition velocities; while the higher molecular weight (HMW) PAHs, which are mainly associated with particulates, have higher dry deposition velocities. The mean dry deposition velocities for LMW PAHs ‐ Nap, AcPy and Acp ‐ are 0.011, 0.034 and 0.043 cm sec‐1, respectively. However, the dry deposition velocities of10 HMW PAHs, including BbF, BkF, BeP, BaP, PER, IND, DBA, BbC, BghiP and COR, are all at the same level but up to 2 orders of magnitude higher than those of LMW PAHs. Because of the “synergism”; of higher fraction in particle‐phase and higher deposition velocity, more than 94% of the HMW PAH mass in the dry deposition flux is contributed by the particle phase.

Monitoring and modeling of PCB dry deposition in urban area

Dry deposition and air sampling were undertaken simultaneously in the ambient air of an urban site by using several dry deposition plates, two MOUDIs (micro-orifice uniform deposited impactors), one NRI (Noll rotary impactor) and several PS-1 (General Metal Work, PS-1) samplers from January to May 1994 in Tainan City, Taiwan. The dry deposition plate, which had a smooth surface, was always pointed into the wind. The PCB (polychlorinated biphenyl) congeners were analyzed primarily by using a gas chromatograph with a 63Ni electron capture detector (ECD). The measured dry deposition flux of total PCBs varied between 3.48 and 6.79 μg m −2 per day and averaged ≈ 4.73 μg m −2 per day. This was up to three orders of magnitude higher than the fluxes measured at the Great Lake and remote areas and close to those measured at urban areas by previous studies. The particle-bound PCB homologue composition collected by the dry deposition plate varied between 0.76 μg g −1 (di-CBs) and 11.5 μg g −1 (hexa-CBs). This profile of PCB homologues is similar to the pattern of Aroclor 1260 which is dominant in hexa-CBs and hepta-CBs. Because of their higher vapor pressure, in general, the less-chlorinated PCB homologues have a greater PCB mass fraction in the gas phase. The mean dry deposition velocities of PCB homologues ranged between 0.09 and 0.58 cm s −1. In general, the more highly chlorinated PCB homologues have a higher dry deposition velocity. Particle size distributions ( dC d(log D p ) vs. D p) of total PCBs were found to be bimodal. The highest peak was localized in the particle size range between 5.6 and 10.0 μm and the second peak was localized in the particle size range between 0.31 and 0.52 μm. The particle MMD 0 of total PCBs was 1.68 μm and more than 85% of the PCB mass was found in the particles smaller than 10 μm. By using the particle size distribution data, the dry deposition model used in this study can provide a good prediction for the dry deposition flux of total particle mass, total PCBs and PCB homologues. For both total particle mass and total PCBs, more than 87.5% of the dry deposition flux is contributed by particles of size > 10 μm. This is because particles larger than 10 μm have a higher dry deposition velocity (> 2.60 cm s −1) and, therefore, control the majority of the dry deposition flux.

LINE ADMITTANCE AT THE JUNCTION OF TWO PLATES WITH AND WITHOUT FLUID LOADING

A time harmonic line force or moment is applied at the junction of two plates in welded contact, with or without unilateral fluid loading. The objective is the 2 x 2 matrix of admittances relating the applied force and moment to the deflection and rotation at the load. The structural asymmetry leads to coupling between force and rotation, and between moment and deflection, even in the absence of fluid loading. The impedance matrix is derived for sources with linear phase variation of the form e ik, y for real k y . The dry plate problem is addressed first, and displays the possibility of a resonance when the drive is in phase with a flexural Stoneley wave, which is defined here. The fluid-loaded problem is attacked by expressing the vibration of either plate and the acoustic response in the fluid as transforms, the integrands of which are derived using the Wiener-Hopf technique. It is found that the wet response shows the same general behaviour as for the dry plates, but without possibility of a structural resonance. Numerical examples are presented showing the frequency dependence of the admittance matrix for joined steel plates in water. The general theory for distinct plates under fluid loading also provides a new formula for the line admittance of a uniform plate in a fluid.

特集 省エネ・省資源と表面処理 乾式めっきにおける省エネ・省資源

特集 省エネ・省資源と表面処理 乾式めっきにおける省エネ・省資源

The use of Petrifilm™ for the enumeration of lactococci

Abstract Petrifilm™ aerobic plate counts were compared to Elliker and M17 agar counts for the enumeration of Lactococcus strains. There were no significant differences between counts obtained with the three methods, which suggests that Petrifilm™ plates can be used as a time-saving method for the determination of lactococci starter populations. The standard method of using Petrifilm™, in which 1 ml of sample is analysed, can be modified to have multiple inoculations on the same dry medium culture plates, such that four aliquots of 0·1 ml are added to a single Petrifilm™ plate. Counts obtained with the multiple inoculation method did not differ significantly from the standard single inoculation method recommended by the Petrifilm™ manufacturer.

無常を説くマニ教ソグド語文書

In this article one Manichaean Sogdian fragment is edited. Two old dry plates of the fragment, which was further broken into two pieces, are preserved at the Department of Oriental History, Kyoto University. Although the present whereabouts of the original is not known, circumstances suggest that it once existed in Japan, and that the photographs were made for the late Professor Toru Haneda of Kyoto University, who had a reputation of being a good decipherer of old manuscripts unearthed from Central Asia.From its contents and handwriting it can be proved that the fragment immediately precedes the so-called “Job Story” published by W. B. Henning (BSOAS 11, 1945, 485-87). The combined text spends all 50 lines (11. 28-50 being a ‘Job Story’) expounding vanity and impermanence of earthly life and bears strong similarity to the “lament for impermanence” found in the Chinese Manichaean hyannscroll 11. 83-119. One excerpt will illustrate this. Compare the following Sogdian passage with line 102 of the hyninscroll.(26) … rty cnn ZKw pryw ZY cnn syrxwz-'k ZY ZK (27) xwtm wxsty c'nkw ZY ZK r'δch ZY ZKw (xw'kkr'k?) ky ZY kβnh (28) (')z-mnw ''wx'n'yt 'skw'nt ZY ZKw 'nw'stk rty pts'r yxw'y'nt (29) (x)w 'yw cnn δβtyk w'nkw 'PZY xwy'r ZK 'yw δn δβtyk L' wyn'nt “He will be separated from his loved ones, friends and relatives like travellers and merchants who stay together for a little while under the same roof, but later separate from each other so that they do not meet each other easily.”_??__??__??__??__??__??__??_/_??__??__??__??__??__??__??_/_??__??__??__??__??__??__??_/_??__??__??__??__??__??__??_“The temporal relations of a family, which are mundane truth, How far do they differ from that of staying at a traveller's inn? Masses of persons stop and rest together for a night; In the morning, they separate and return to their own lands”, cf. Tsui Chi, BSOAS 11, 1943, 185.Such hapax legomena and rare words as δxst'k “ripe”, prkwxs “swaying”, and 'pw ptspnyh “vanity?” found in the text make the fragment intriguing also from the philological point of view.

Dry instant blood typing plate for bedside use

A monoclonal antibody-derived, dry blood grouping plate, based upon the simple disaccharide, trehalose, is described that is indefinitely stable at room temperature and was found to have a 99·8% accuracy when tested against a standard semiautomated assay. This plate can be used by personnel with no specific training to check the recorded A,B,O, and Rhesus blood type of potential transfusion recipients in the field and at the bedside. Trehalose-based reagents may be important for bedside testing and in developing countries where refrigeration is unreliable.

Bloodtyping at the bedside by a trehalose-treated dry plate

Bloodtyping at the bedside by a trehalose-treated dry plate

Prediction of the shelf‐life of pasteurized milk using dry medium culture plates (3M Petrifilm, Hygicult and Millipore Sampler)

Petrifilm SM Plate. Hygicult and Millipore Total Count Sampler were compared with normal plate count procedures for the enumeration of bacteria after preincubation of pasteurized milk. There were good correlations between results obtained using normal plate counts and those obtained with each of the other methods. Coupling these counting methods with preincubation procedures of 21°C for 25 hours in the presence of crystal violet‐penicillin‐nisin allowed prediction of the pass rate of the recently introduced 6°C/5 day storage test for pasteurized milk. The predictive accuracy was slightly improved by the use of preincubation conditions of 15°C for 25 hours. The availability of these devices enables quality control procedures to be set up on even the smallest processing site.

Features of exclusion thin-layer chromatography of polymers

Features of exclusion thin-layer chromatography of polymers have been investigated on dry plates. It was found that an increase in the amount of polymer p being applied leads to elongation and then to partial destruction of chromatographic zones advancing with the eluent front. For polymers with a distribution coefficient k d >0 the length of the zone depends not only on p and on the intrinsic viscosity [η], but also on the chromatographic (zone) spreading. An increase in the size of sorbent grains d s leads to the appearance of artificial zones: “tails”, and spots at the start. The completeness of polymer elution from the starting zone depends on the size of the macromolecules in relation to that of the sorbent grains, and on the rate of elution, as well as on the conditions of sample preparation in the case where k d = 0 (with or without drying at the starting zone). Elution of the plates with a polymer solution results in an increase in the concentration of macromolecules for which k d <1 at the eluent front.

Termal behavior of main spindle driving system with electromagnetic disk clutch of dry single plate type in machine tool.

Regarding the thermal behavior of the main spindle driving system with the electromagnetic disk clutch, experimental investigations have been carried out in both the rotational and nonrotational conditions, in which the visualization of the temperature distribution has also been employed. This paper presents some interesting observations obtained from such experiments, and gives very useful guidelines to reduce the thermal behavior in designing such a driving system. For instance, the results show that the frictional heat of the clutch bearing strongly affects the thermal behavior of the friction disk, driven shaft, magnetic body and that the slip characteristic of the clutch has considerable effects on the thermal behavior of the system. In addition, this paper suggests that the self-ventilation using the rotational friction disk is the most effective in reducing the thermal influence on the system.

Convective Heat Transfer Distributions on a Plate Cooled by Planar Water Jets

Convective heat transfer distributions have been measured for planar water jets impinging on a plate. The cooling effectiveness of two nozzles, each with a different discharge width, is compared for a range of impingement velocities. Measurements were made under transient conditions, and results are presented both during and after the period for boundary layer growth on an initially dry plate. Heat transfer correlations and discussions of pertinent parametric effects are provided.