Clear Polyvinyl Chloride Research Articles

Development of multifunctional curcuminoid dye-based inks and applications

Curcuminoids are a group of naturally occurring polyphenolic compounds found in turmeric (Curcuma longa) that are widely employed as coloring agents in traditional medicine and the food industry. Moreover, they have been used as dyes in pH indicators, which are part of diagnostic intelligent packaging. Recently, there has seen a steady increase of the interest in the curcuminoids due to their fluorescent property. In this study, a curcuminoid dye (CurD) containing a total curcuminoid content of 38.34 ± 0.66 % w/w was prepared by using a microwave-assisted extraction, and was used as a multifunctional dye with different commercial screen binders, including solvent-based ink (Si) and water-based ink (Wi). A solution of CurD (0.1 % w/v) exhibited a maximum fluorescence wavelength of 526 nm. Based on the print-quality test using a screen printing on clear polyvinyl chloride and paper, the viscosity and drying time of CurD-Si and CurD-Wi inks were not significantly different. The printed-inks had a yellow color under illuminant D50 and D65, and exhibited remarkable green fluorescence under UVA (365 nm). The total color differences (∆Eab∗), which are not fluorescence intensities, of both inks were changed by increasing CurD concentrations. CurD-Wi containing 1 % w/w CurD could be printed as latent graphics on a paper label for use as an anti-counterfeiting application. In addition, it immediately responded to alkaline solution and vapor through color transition from yellow to orange-brown, with the maximum ∆Eab∗ values of 15.02 and 26.62, respectively. In contrast, all CurD-Si samples could fluoresce but did not respond to alkaline conditions.

Plastisisation of polyvinilchloride biofilms with palm oil oleine and methylmethacrylate as comonomer

Polyvinylchloride (PVC) is the second largest thermoplastics produced after polyethylene (PE), polypropylene (PP) and polystyrene (PS), especially for packaging, households, toys, and other commodity products. However when used for food packaging, PVC has to be plastisised using plastisisers (added upto 30%), which may not comply with safety requirements for food biofilms. Palm oil oleine (POO) is a nontoxic and edible triglyceride containing double bond and can be bounded onto PVC backbone in the presence of methylmethacrylate (MMA) as comonomer and benzylperoxide (BPO) as initiator. The PVC resin was dissolved in tetrahydrofurane (THF), added with POO, MMA and BPO, (in various compositions), under constant stirring in a reflux reactor. The reaction mixtures were then refluxed for 3 hours under nitrogen atmosphere at constant pressure 1 atm. Plastisised PVC films were obtained after casting the reaction mixtures on a glass plates, and dried under vacuum at constant temperature 40°C. Mechanical properties of the films were tested and their morphology were analysed under scanning electron microscope (SEM) and FTIR spectoscopy. Optimum clear and flexible PVC films was obtained when weight composition of the reaction mixture: PVC/MMA/POO/BPO: 2/0.5/0.5/0.35. Elongation at break of the optimum film was more than 95% higher, whereas the tensile strength was 60% lower when compare to those of pure casted PVC film. SEM analysis of the film surface also showed good homogenous morphology, whereas analysis of FTIR spectra of the films before and after exhausted washing in n-hexane, indicating 48.5% binding of MMA and POO in the PVC films.

Flow pattern and pressure drop for oil\u2013water flows in and around 180\xb0 bends

Pressure drop and flow pattern of oil–water flows were investigated in a 19-mm ID clear polyvinyl chloride pipe consisting of U-bend with radius of curvature of 100 mm. The range for oil and water superficial velocities tested was 0.04 le U_{{{text{so}}}} le 0.950 ;{text{m/s}} and 0.13 le U_{{{text{sw}}}} le 1.10 ;{text{m/s}}, respectively. Measurements were carried out under different flow conditions in a test section that consisted of four different parts: upstream of the bend, at the bend and at two redeveloping flow locations after the bend. The result indicated that the bend had limited influence on downstream flow patterns. However, the shear forces imposed by the bend caused some shift flow pattern transition and bubble characteristics in the redeveloping flow section after the bend relative to develop flow before the bend. Generally, pressure gradient at all the test sections increased with both oil fraction and water superficial velocity and there was a sharp change of pressure gradient profile during phase inversion. The transition point where phase inversion occurred was always within the range of 0.4 le U_{{{text{sw}}}} le 0.54 ;{text{m/s}}. Pressure losses differed at the various test sections, and the difference was strongly linked to the superficial velocity of the phases and the flow pattern. At high mixture velocity, pressure losses at the redeveloping section after the bend were higher than that at the bend and that for fully developed flows. At low mixture velocity, pressure losses at the bend are higher than in the straight sections. Pressure drop generally decreased with level of flow development downstream of the bend.

Laboratory Experiments on the Removal of Soil Plugs During Soil Piping and Internal Erosion

Abstract. Plugging of soil pipes can be detrimental to hillslope stability. A soil pipe commonly becomes plugged through internal erosion when the pipe wall collapses. When a pipe becomes plugged, a pressure buildup occurs upslope from the plug. This pressure may be enough to remove the plug, or the pressure may continue to build in the soil matrix, which may lead to hillslope failures. Based on field observations, it is known that both processes occur, but limited data exist to understand if and when plug removal or pressure buildup occurs or how to model these processes. This study involved well-controlled laboratory experiments to determine instantaneous pressure buildup behind soil plugs and conditions for which an idealized plug in a soil pipe will be removed. Laboratory experiments were conducted with a smooth or roughened 100 cm long clear polyvinyl chloride (PVC) pipe. A pipe plug (3 or 6 cm) was established 90 cm along the pipe length. Triplicate experiments were conducted with two pipe diameters, two soil types (sand and sandy loam), two plug lengths, three pipe roughness values, various packing densities, and with both dynamic and constant pressure heads. Digital pressure gauges were installed to monitor pressures in the pipe both before and after the plug. The upslope pressure and the length of time that the plug withstood the pressure before removal were recorded. Regardless of pressurized time, all plugs were initially mobilized as intact plugs and then in many cases quickly disaggregated. Some sandy loam plugs withstood pressures of 100 cm; more cohesive plugs could withstand much higher pressures. In addition, pressurized times exceeded 1000 s for some plug conditions even with short (3 to 6 cm) plugs. Therefore, hillslopes upslope of a plugged soil pipe may experience considerable pressure buildup for extended periods of time. Plug physical characteristics are important; for example, the plug’s bulk density had a positive exponential relationship with the pressurized time. Soil water dynamics inside the plug will need to be considered, as well as the hydraulic boundary providing inflow to the soil pipe. These experiments provided insight into the dynamics of plugged soil pipes with the eventual goal of assisting in being able to better predict internal erosion and hillslope failure. Future experiments are needed across a wider range of soil types. Keywords: Hillslope, Internal erosion, Macropore, Pipe clogging, Pipeflow, Pressure buildup, Sediment transport, Soil plug.

Nectar intake and foraging efficiency: the responses of sunbirds to flower morphology

Floral traits vary greatly between plant species, and determine which pollinators are physically capable of accessing floral rewards and carrying out effective pollination. Research on the responses of nectarivorous birds to different flower morphologies has been largely restricted to hummingbirds, while other flower specialists, the sunbirds and honeyeaters, remain relatively unstudied. We investigated how flower morphology influences the foraging behaviour of White-bellied Sunbirds, Cinnyris talatala. Using artificial flowers made of clear polyvinyl chloride tubing and filled with 20% w/w sucrose solution, we measured maximum extraction depths of sunbirds foraging at 3- and 5-mm-wide flowers at both upward and downward orientations. Flower width, but not orientation, strongly influenced maximum extraction depth, with the birds probing deeper at wider flowers. Foraging bout dynamics were tested at these two diameters and at two corolla lengths, 14 and 27 mm; birds fed faster at wider and at shorter flowers, when length and diameter were tested separately. In combination treatments, sunbirds fed fastest at the short and narrow flowers where the fixed volume of nectar was easier to reach. When given a choice between two floral lengths or two floral diameters, birds preferred short flowers, with diameter having no effect. Floral length appears to be more important than width in determining sunbird foraging behaviour, and White-bellied Sunbirds should be effective pollinators of short tubular flowers. The lack of effect of orientation is perhaps surprising when many sunbird-pollinated plants have downward-facing flowers.

In Vitro Comparison of Stone Fragmentation When Using Various Settings with Modern Variable Pulse Holmium Lasers.

There are limited data regarding optimal laser and energy settings during stone fragmentation. We assessed effects on fragmentation using a variety of energy and frequency settings with two laser systems. Artificial stones were created using BegoStone. A clear polyvinylchloride (PVC) tube with an inner diameter of 13 mm was closed at one end with a removable plug to create the in vitro ureteral and caliceal environments. The Lumenis Pulse 120H and the Cook Rhapsody H-30 holmium lasers were studied in the caliceal and ureteral models. A single urologist fragmented each stone to <2 mm. The caliceal studies assessed the time to fragmentation (n = 56). The ureteral studies measured the retropulsion distance of each stone phantom after 5 minutes of laser treatment time using different pulse width settings (n = 15). Complete treatment of the stone with the 120H required 10.9 minutes at ≥1 J vs 26.9 minutes at <1 J (p < 0.001). The H-30 showed similar results with treatment times of 11.2 minutes at ≥1 J vs 22.8 minutes at <1 J (p < 0.001). There was no significant difference in treatment time when comparing the two lasers using settings of 0.8 J × 8 Hz and 1.5 J × 10 Hz (25.5 minutes vs 24.8 minutes, p = 0.861; and 13.2 minutes vs 9.5 minutes, p = 0.061; respectively). Retropulsion distances using the 120H were 13.9 cm using long pulse, 25.2 cm using medium pulse, and 56.6 cm using short pulse. Retropulsion distances using the H-30 laser were 7 cm using long pulse and 14.5 cm using short pulse, which differed from the 120H (p < 0.001). Laser fragmentation was faster with both lasers when energy settings of ≥1 J were used. Treatment times using the 120H and the H-30 lasers were equivalent. Retropulsion distances were less with both lasers when longer pulse widths were used. The H-30 resulted in less stone retropulsion compared with the 120H.

In Vitro Comparison of Holmium Lasers: Evidence for Shorter Fragmentation Time and Decreased Retropulsion Using a Modern Variable-pulse Laser

To compare the performance of variable- and fixed-pulse lasers on stone phantoms in vitro. Seven-millimeter stone phantoms were made to simulate calcium oxalate monohydrate stones using BegoStone plus. The in vitro setting was created with a clear polyvinyl chloride tube. For each trial, a stone phantom was placed at the open end of the tubing. The Cook Rhapsody H-30 variable-pulse laser was tested on both long- and short-pulse settings and was compared to the Dornier H-20 fixed-pulse laser; 5 trials were conducted for each trial arm. Fragmentation was accomplished with the use of a flexible ureteroscope and a 273-micron holmium laser fiber using settings of 1 J × 12 Hz. The treatment time (in minute) for complete fragmentation was recorded as was the total retropulsion distance (in centimeter) during treatment. Laser fibers were standardized for all repetitions. The treatment time was significantly shorter with the H-30 vs the H-20 laser (14.3 ± 2.5 vs 33.1 ± 8.9 minutes, P = .008). There was no difference between the treatment times using the long vs short pulse widths of the H-30 laser (14.4 ± 3.4 vs 14.3 ± 1.7 minutes, P = .93). Retropulsion differed by laser type and pulse width, H-30 long pulse (15.8 ± 5.7 cm), H-30 short pulse (54.8 ± 7.1 cm), and H-20 (33.2 ± 12.5 cm) (P <.05). The H-30 laser fragmented stone phantoms in half the time of the H-20 laser regardless of the pulse width. Retropulsion effects differed between the lasers, with the H-30 causing the least retropulsion. Longer pulse widths result in less stone retropulsion.

Late Fall Nitrogen Application and Turf Cover for Zoysiagrass (Zoysia japonica) Spring Green-up

The use of zoysiagrass (Zoysia japonica Steud.) in the transition zone is limited because of a lack of cold hardiness although zoysiagrass has many advantages compared to other warm-season and cool-season grasses. Late-fall N fertilization is often applied for darker green color of turfgrass in early spring and more extensive root growth without rapid top growth. The objective of the study was to evaluate the effects of late fall N application and turf cover for zoysiagrass spring green-up. Clear polyvinyl chloride (PVC) film was used for turf cover. The amount of N applied were 5 and 10 g N m −2 for the low and high N rate treatments, respectively. Covered zoysiagrass had greater turfgrass color and quality in early spring than non-covered zoysiagrass. The high N rate had 0.6 to 2.3 greater turfgrass quality than the low N rate on 7 of 9 rating dates. Slow-release N as late fall fertilization is more effective for turfgrass color and quality than fast-release N in spring. Turf cover could reduce the period of yellow zoysiagrass, and the earlier time of spring green-up could be advanced by increasing turfgrass quality and growth of zoysiagrass.

Drought Resistance Strategies of Seashore Paspalum Cultivars at Different Mowing Heights

Understanding how mowing height and soil moisture influence drought resistance mechanisms may lead to better management of seashore paspalum. This research was conducted to evaluate the effect of mowing height and soil moisture replacement on drought tolerance strategies in three seashore paspalum cultivars. In a greenhouse, clear polyvinyl chloride (PVC) root tubes were placed in a black PVC sleeve with a bottom cap drilled with holes for drainage. Sod pieces (10 cm in diameter) of seashore paspalum (Paspalum vaginatum Swartz) cultivars Salam, Excalibur, and Adalayd were planted into these tubes after roots were trimmed. In a split-split experimental design, water regimes applied included control [100% of the total evapotranspiration (ET)] as well as 75%, 50%, and 25% of the total ET. Mowing heights were 45.0, 35, and 25 mm. Visual turf quality, maximum root extension (MRE), root length densities (RLD), total nonstructural carbohydrate content (TNC), shoot reducing sugar content (RSC), and proline content were determined. Turf quality decreased linearly with the decrease in irrigation water applied under the three mowing heights with higher slope at 25.0 mm than at either 35.0 or 45.0 mm. ‘Salam’ turf quality declined only to the unacceptable rating of 5.5 and 4.5 when mowed to 35 and 25 mm, respectively, whereas quality was 6.5 at the mowing height of 45 mm under the water regime of 25% of total ET. ‘Excalibur’ did not show acceptable turf quality at the 25% treatment, whereas ‘Adalayd’ did not show such quality at both 50% and 25% water regimes under all mowing heights. Regression analysis indicated a significant negative association between RLD and drought levels at all mowing heights and soil depths. In ‘Salam’, as drought levels increased from control to 25%, average RLD decreased by 76%, 75%, and 76% at 25-, 35-, and 45-mm mowing heights, respectively, at the top 30 cm of soil in the column. The change was 93%, 85%, and 83% at 25-, 35-, and 45-mm mowing heights, respectively, at the deeper soil (90 to 120 cm). In ‘Salam’, on average overall water regimes, MRE at 45 mm was ≈10% to 17% greater than that of 35-mm mowing height and 28% to 36% greater than that of 25-mm mowing height. The highest root mass (810 mg) was obtained when ‘Salam’ was mowed to 45 mm and subjected to the drought level of 50% of the total ET. The lowest root mass (320 mg) was obtained when ‘Salam’ was mowed to 25 mm and the water regime was not limiting. In ‘Salam’, as drought increased from control to 25% of the total ET, average TNC decreased by 43.5%, 26.0%, and 29.0% and the average TNC decrease in ‘Excalibur’ shoots was 48.0%, 30.0%, and 32.0%, whereas the decrease in ‘Adalayd’ was 51.3%, 42.3%, and 35.4% at 25-, 35-, and 45-mm mowing heights, respectively. As drought levels increased from control to 25% of the total ET, average RSC increased by 57.3%, 57.1%, and 53.0% in ‘Salam’ and by 59.4%, 57.0%, and 51.5% in ‘Excalibur’ and 61.2%, 58.1%, and 61.0% in ‘Adalayd’ at 25-, 35-, and 45-mm mowing height, respectively. When drought increased to 25%, average proline content in shoots increased by 435%, 432%, and 431% in ‘Salam’; 404%, 376%, and 324% in ‘Excalibur’; and 257%, 278%, and 302% in ‘Adalayd’, at 25-, 35-, and 45-mm mowing heights. The resistance of paspalum cultivars to moderate to high drought stress can be enhanced by increasing the mowing height that may be related to increased carbon fixation, which favors increased root production. Proline accumulation could add to the drought tolerance through osmoregulation or by acting as a carbon and nitrogen sink for stress recovery.

Galata Chemicals extends Drapex Alpha family of bio-based plasticizers for PVC

Polymer additives specialist Galata Chemicals has introduced Drapex® Alpha 200C as the latest addition to its recently introduced [ADPO, June 2012] Alpha series of natural oil-based primary plasticizers. The new bio-based offering has been designed for use in white and clear polyvinyl chloride compounds as well as speciality applications with demanding performance requirements, the company says.

Vibration Analysis of Blocked Circular Pipe Flow

Pipes are found in almost all buildings and constructions where they are used to convey fluid to a desired location. Liquid containing foreign objects and impurities will sometimes creates unintentional built up or clog obstruction along the interior surface of the pipeline. This phenomenon may affect the fluid flow within the pipe. This work analyzed the impact of different blockage sizes inside a clear Polyvinyl Chloride (PVC) circular pipe using vibration measurement. Observations were made on the fluid flow patterns during the flow. This work encompasses the correlation between blockage thickness inside a circular pipe and vibration parameters.

Coating the inner surfaces of pipes with high-viscosity epoxy in annular flow

Applying a thin, protective coating of a nontoxic, chemically resistant epoxy to the interior of existing pipes is an alternative method to pipe replacement. In order to find the controlling parameters in this method, in this study, viscous epoxy was propelled by compressed air through clear polyvinyl chloride (PVC) pipes. Epoxy flow was annular, and it hardened to form a thin, uniform coating on the inner pipe surface. A video camera was employed to record fluid motion, and the thickness of the coating was measured using an image analysis program named ImagJ. Tests were done with varying air temperature, airflow rate, piping configuration, and epoxy temperature. A one-dimensional numerical algorithm was developed to model fluid flow, heat transfer, and epoxy curing. Heating the epoxy makes it move faster because liquid viscosity decreases with increasing temperature. The coating was significantly thicker at the bottom of a horizontal pipe than at the top due to sagging of the epoxy coating after it had been applied, resulting in flow from the top to the bottom of the pipe. Sagging could be reduced by maintaining airflow until curing was almost complete and the epoxy had hardened enough to prevent it from moving easily. The combination of the experimental results and numerical modeling showed that the most important parameters controlling the speed of the epoxy and coating thickness were the air flow rate and temperature, since they determine the shear forces on the epoxy layer and the rate at which the epoxy cures. Raising air temperature increases the reaction rate and therefore decreases the time required for the epoxy to cure inside the pipe. The results of the simulation showed a very good agreement with the experimental results in pipes with 1-in diameter or less.

Beneficial effects of oxygen addition and hybrid poplar phytoremediation of petroleum-contaminated soils

Laboratory scale experiments were conducted to investigate the effect of a phytoremediation system using poplar trees on the smear zone-soil gases for petroleum hydrocarbons contaminated soil. Eight clear polyvinyl chloride (PVC) columns (1.5 m × 0.1 m) were packed with the contaminated soil covered with clean top soil. Five ports were installed on the front side of each column for soil gas sampling. Hybrid poplar trees (Populus deltoides X nigra DN34) were grown in 4 columns. The remaining four columns were used as controls (no trees). Three of the tree columns and 3 of the controls had induced air flow. An experimental apparatus was established to allow for the induced air to flow through the air flow columns. Average air flow rates of 0.43 L/d, 0.71 L/d and 1.50 L/d were tested. The columns were operated for 78 days. During the experiments, the effect of oxygen addition, through the induced air, on the development of poplar roots in the hydrocarbons contaminated soil was investigated. In addition, the compositions and concentrations of the soil gases at different soil depths were evaluated during the course of the experiments.

The Interaction of Light and Gravity on the Transmission of Echinostoma caproni (Digenea: Echinostomatidae) Cercariae to the Second Intermediate Host, Biomphalaria glabrata (Gastropoda: Pulmonata)

The current experiments were designed to assess the interaction of light and gravity on the transmission of Echinostoma caproni cercariae to the second intermediate host, Biomphalaria glabrata. Transmission chambers were constructed of clear polyvinyl chloride pipe covered with a black sleeve to exclude light. Snails were constrained within the chamber to prevent movement, while permitting the cercariae to swim freely. A trial consisted of 2 infected B. glabrata shedding E. caproni cercariae placed at the center of the chamber with 5 uninfected B. glabrata placed 10 cm above and below the shedding snails as sentinels. Three experiments, consisting of 12 trials each, were conducted under the following lighting conditions, i.e., above and below the transmission chamber, and in complete darkness. In all 3 experiments, the proportion of metacercariae was significantly higher in snails at the top of the chamber. The results suggest that a negative geotaxis is the primary factor in the initial dispersal of E. caproni cercariae. Coupling negative geotaxis and positive phototaxis (light from above) resulted in a significantly higher proportion of metacercariae in sentinel snails at the top of the transmission chamber when corrected for cercarial density. There was no significant difference in the proportion of metacercariae in snails at the top or bottom of the transmission chamber with light at the bottom of the chamber or in complete darkness. Cercariae of E. caproni only respond to light in context, i.e., from above, and ignore the light stimulus when it comes from an unexpected location (bottom of the water column). Significantly greater numbers of cercariae were released from shedding snails when light was present, suggesting that emergence of cercariae from B. glabrata is dependent on light regardless of the position of the light source.

The Role of Light and Gravity in the Experimental Transmission of Echinostoma caproni (Digenea: Echinostomatidae) Cercariae to the Second Intermediate Host, Biomphalaria glabrata (Gastropoda: Pulmonata)

Trematode cercariae inhabit predictable environments and respond to trigger cues with genetically fixed releaser responses when foraging for the upstream host. The effect of light and gravity on the transmission of Echinostoma caproni cercariae to Biomphalaria glabrata was investigated experimentally. Transmission chambers were constructed of clear polyvinyl chloride pipe. Snails were constrained within the chamber to prevent movement, while permitting the cercariae to swim freely. A trial consisted of 2 infected B. glabrata shedding E. caproni cercariae placed at the center of the chamber, with 5 uninfected B. glabrata placed 10 cm on either side (or above and below) of the shedding snails as sentinels. There was no significant difference in the prevalence of infection sentinel snails in either experiment (light vs. dark or top vs. bottom); however, mean intensity was significantly higher in sentinel snails in the dark portion of the chamber (42.5 vs. 10.4; P = 0.001) and the top of the transmission chamber (66.1 vs. 38.0; P = 0.0003). There was a high correlation between the number of metacercariae collected from sentinel snails and the total number of infective units (metacercariae + unsuccessful cercariae): r = 0.992 (light vs. dark) and r = 0.957 (top vs. bottom), respectively, at cercariae densities estimated from 22 to 3,304/L. The results suggest that cercariae of E. caproni exhibit negative photo- and geotaxis in searching for a second intermediate host. Stereotypical releaser responses to environmental trigger cues (light and gravity) allow E. caproni cercariae to exploit flexible strategies for completing the life cycle consistent with the broad range second intermediate and definitive hosts used by E. caproni cercariae and adults, respectively.

ESTIMATING FINE_ROOT LONGEVITY OF FRAXINUS MANDSHURICAAND LARIX GMELINII USING MINI-RHIZOTRONS

Aims Fine-roots (≤2 mm diameter) are important in controlling energy and matter exchange between tree and soil. Fine-root longevity is a critical determinant of fine-root turnover and therefore carbon allocation and nutrients returned to the soil. However, little is known about variation in fine-root longevity in relation to spatial and temporal heterogeneity in availability of soil resources (such as temperature, moisture and nitrogen). How does availability of soil resources affect fine root longevity? Do different tree species, soil depths and root cohorts have different fine-root longevity in the same forest site? To answer these questions it is important to understand the fate of fine roots in soil with heterogeneous resource availability. The objectives of this study were to: 1) compare fine-root longevity between ash (Fraxinus mandshurica) and larch (Larix gmelinii) in the same site, 2) define patterns of fine-root longevity in different soil depths and elucidate the effect of availability of soil resources on fine-root longevity and 3) analyze seasonal changes of fine-root longevity for both species. Methods Mini-rhizotrons (root observation tubes) were used to estimate fine-root longevity. We established three 20 m×30 m plots in an ash and larch plantation, and installed six clear PVC (polyvinyl chloride) mini-rhizotron tubes (90 cm long × 5.5 cm inside diameter) in each plot in October 2003. From 16 April to 30 October in 2004, video images were collected from the mini-rhizotron tubes at approximately two-week intervals and analyzed with an image analysis system (RooTracker software). We compared differences in longevity between tree species, soil depths and seasonal root cohorts using cumulative survival rate and median root longevity (MRL) of fine roots by Kaplan-Meier methods in survival analysis. Important findings Cumulative survival rate of fine roots decreased gradually with time. Survivorship curves showed that cumulative survival rate of fine roots in ash was significantly higher than that in larch (p 0.001 ); MRL was 111±7 d in ash and 77±4 d in larch. Higher fine root mortality was found in 0-20 cm soil, as MRL was 62±11 d for larch and 111±6 d for ash, contrasting with 95±11 d for larch and 124±20 d for ash in deep soil. This study also indicated longer lifespans of fine roots produced in summer (82±6 d for larch) than spring (47±13 d). Similar seasonal pattern was found for ash. Fine-root longevity was different between tree species due to different root genetics, physiology and architecture. High soil temperature and high N content can decrease fine root longevity. In summer, photosynthates are allocated to roots and fine roots grow rapidly and have increased longevity. Our results suggested that fine-root longevity is correlated with genetics of the species, physiological status and soil resource availability.

超音波顕微鏡観察による防食塗膜の劣化挙動の評価 ２ 各種塗膜系の比較

The deterioration behavior of pigmented epoxy (EP-P), clear epoxy (EP-C) and clear polyvinyl chloride (PVC-C) coated steel in an aqueous 3% NaCl solution was investigated by scanning acoustic microscope (SAM). Results of experiments showed that SAM can be used to identify and determine the extent of disbonding due to blisters on any kind of coatings applied on steel. For clear coating film, the characteristics and the nature of blisters on the coating film were substantially observed by the SAM than by visual inspection. As for the analysis of SAM imaging, the disbonded area increased linearly with increasing immersion time in an aqueous 3% NaCl solution. The percentage of disbonded area was found higher on pigmented coating films than on clear coating films. The linear relationship between the percentage of disbonded area by the SAM and the coating film resistance (Rf) by electrochemical impedance spectroscopy (EIS) might or might not be unequivocally shown. The relation was due to a mode of deterioration of coating film, a mode of under-corrosion of coating film, etc.

Odor and PVC: Identification and quantification of volatiles in clear polyvinyl chloride processing

AbstractTrapping experiments will be described in which standard workplace monitoring devices were used to collect samples over the dynamic mill, Brabender, and single screw laboratory extruder. Additionally, the results of static (unsheared) heating on clear PVC compound and finished goods with collection of emitted organic vapors are compared to the dynamic case. Identification and quantification of the possible contributors to process odor will be discussed.

Design and Performance of a Large, Field Exposure Chamber to Measure Effects of Air Quality on Plants

AbstractA 4.66‐m diam., 3.6 m tall, cylindrical open‐top field chamber was designed, constructed, and tested as a tool to measure the effects of air quality on plant function and yield. It is a larger version of the 3‐m diam. chamber that has been used to measure the effects of gaseous pollutants on crop plants. The new chamber has an aluminum‐channel frame covered with clear polyvinyl chloride plastic film. It is equipped with a frustum (truncated cone) that decreases ambient air ingress and can be fitted with a device to exclude rain (rain cap) for studies with simulated rain pH. During the daylight hours, the mean air temperature within the chamber was 0.6 °C greater than ambient on cloudy, cold days, 2.2 °C greater than ambient on partly cloudy, cool days, and 2.8 °C greater than ambient on sunny, warm days. The mean dew point temperature for a wide range of conditions was 0.7 ° greater inside than outside. Mean solar radiation in the chamber, with new plastic panels, was 15% less than ambient with a rain cap and 12% less with no rain cap. Charcoal filtration removed 78% of the O3 in ambient air; long‐term measurements during charcoal filtration showed that the mean O3 concentration in the chamber (all positions and heights) was 77% less than ambient suggesting little or no long‐term ingress through the top. Short‐term gradients in O3 concentrations existed (mostly near the top of the chamber) during infrequent periods of strong winds. During addition of approximately 0.09 µL L−1 of O3 to nonfiltered air, the mean (14‐d) O3 concentrations across all positions and heights varied by less than 0.005 µL L−1 of the overall mean.

Con: Proper Positioning of a Double-Lumen Endobronchial Tube Can Only Be Accomplished With the Use of Endoscopy

T HE GREAT advantage of double-lumen tubes (DLTs) in thoracic surgery is that either or both lungs can be ventilated independently while isolating each lung. Unfortunately, because of problems with their accurate placement, many anesthesiologists do not use these tubes as often as they should. Since a misplaced DLT can result in hypoxemia, airway trauma, and unsuitable surgical conditions, many experts recommend that endoscopy always be performed to ensure their proper positioning. In my opinion, if you choose the appropriate DLT and understand the information easily obtained by carefully listening to breath sounds during their placement, fiberoptic bronchoscopy is seldom, if ever, needed. The three most common positioning complications associated with DLTs are not passing the tube sufficiently far down into the bronchus, intubation of the wrong bronchus, and passing the tube too deep into the correct bronchus resulting in upper lobe obstruction. All these problems can be easily recognized without bronchoscopy by using the following simple technique for DLT placement.’ Following induction of anesthesia, the tip of the DLT is advanced just past the vocal cords, the stylet in the endobronchial lumen is removed, and the tube is rotated 90” in the direction of the bronchus to be intubated. Since most anesthesiologists prefer a left-sided DLT for either right or left thoracotomy, the steps for left endobronchial intubation will be described. The tube should be advanced until moderate resistance to further passage is encountered. Both the tracheal and endobronchial cuffs are then inflated with air. It is essential that a large DLT be used. Men should be intubated with a 41F and most women with a 39F polyvinylchloride (PVC) DLT. Only 1 to 2 mL of air should be needed for the bronchial cuff. If more than 3 mL of air is required to seal the bronchus, the bronchial cuff is either herniating above the carina or may be completely in the trachea. A bronchoscope is not needed to recognize a tube that is not deep enough. The patient should be ventilated with both cuffs still inflated. With a clear PVC DLT, moisture should appear in both lumens. The chest wall is observed for equal movement and is auscultated with special attention for any differences in breath sounds over the left upper and lower lung fields. Next, the tracheal lumen should be occluded with a surgical clamp. Breath sounds should now be heard only over the intubated left lung. If breath sounds are present bilaterally, the tube is far too high in the trachea. If breath sounds are heard only over the right lung while ventilating through the endobronchial lumen, the tube is down the wrong side. This problem is easily remedied by deflating both cuffs, pulling the tube back until its tip is above the carina, and rotating it to the left while again advancing it until resistance is encountered. The left endobronchial lumen should then be clamped and the patient ventilated. Breath sounds should be heard only over the right lung. If there is now difficulty ventilating through the tracheal lumen with a marked resistance to air flow with both cuffs inflated, the tube is either too far into the left bronchus or still not deep enough. At this point, the tube’s position can be determined, without bronchoscopy, by deflating only the endobronchial cuff while continuing to ventilate only through the tracheal lumen with the left (endobronchial) lumen occluded. If the tube is too deep into the left bronchus, breath sounds will now be heard only on the left (Fig 1). If the tube is not deep enough into the bronchus, breath sounds will now be heard bilaterally (Fig 2). Both cuffs should be deflated and the DLT advanced or withdrawn depending on the results of the previous maneuver. Once this sequence of steps is understood, a DLT can be quickly, safely, and accurately positioned in less than a minute. It is important that