White Polyvinyl Chloride Research Articles

Degree of Wettability and Aging of PVC and PET Polymers Treated by Plasma Immersion or Deposition

The wettability, aging characteristics, and optical transmittance in the visible region following Plasma Immersion (PI) or Plasma Immersion Ion Implantation (PIII) treatment of polymers were studied. In addition, structural and chemical modifications of the polymers were examined. The polymers investigated were white Polyvinyl chloride (PVC) and Polyethylene terephthalate (PET). Initially, plasmas of nitrogen (N2) were employed, aiming to produce hydrophilic surfaces. In contrast, sulfur hexafluoride (SF6) plasma treatments produce high surface fluorination, which tends to increase hydrophobicity. Isopropyl alcohol (IPA) was mixed with SF6 or N2 to deposit a series of organic films. Aging effects over 30 days on the contact angle, q, were measured for the polymer surfaces. Conventional plasma immersion (PI) tended to decrease of θ for N2 plasma treatments, with or without IPA, and to increase θ values ​​for samples immersed in IPA/SF6 plasma. The highest value of θ was 140º for IPA/SF6 plasma treatments, while the smallest θ was 20º for N2 or IPA/N2 treatments. There was an ideal condition under which θ was stable upon aging. The results obtained suggest the developed treatment enables the preparation of polymers with distinct wettability properties depending of the nature of the plasma with overall reasonable aging stability. Moreover, the opaque character of these materials makes them interesting for the production of bags, boxes, bottles, food packaging, among others.

In‐field evaporative protection for dryland wheat and lentil crops using polymers

AbstractIn semi‐arid cropping regions where rainfall is variable, stored soil water is important for reducing the impacts of dry periods; however, in‐season evaporation limits yield potential. We tested the productivity benefits of protecting wheat and lentil crops from evaporation using inter‐row polymer cover, when grown in southern Australia. For wheat, white polyvinyl chloride (PVCw) increased yield by 50% (561 kg/ha) and 11% (408 kg/ha) for decile 2 (2018) and 3 (2019) seasonal rainfall respectively; and for lentil, yield increases were 20% (443 kg/ha) in 2019. A sprayable alginate polymer increased wheat yield by 8% (310 kg/ha). Total water use for wheat in 2018 was reduced (17 mm) for PVCw and water use efficiency (WUE) significantly increased from 7 to 11 kg/ha/mm, whereas in 2019, WU was greater (47 mm) for PVCw, but WUE was equivalent to the control (~15 kg/ha/mm). Colour of the PVC modified the light available to the crop and canopy temperature, where a highly reflective inter‐row cover (albedo 0.44) increased wheat yield (~487 kg/ha). For the future, formulations of highly reflective polymers applied in‐season within dryland cropping enterprises are likely to provide production advantages, although logistical viability of application and potential environmental implications may define impediments to adoption.

Application of CEEMDAN combined wavelet threshold denoising algorithm to suppressing scattering cluster in underwater lidar

<sec>The echo of underwater lidar often contains a significant quantity of scattering clutters. In order to effectively suppress this scattering clutter and improve the ranging accuracy of underwater lidar, a novel denoising method based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and wavelet threshold denoising is proposed.</sec><sec>The CEEMDAN-wavelet threshold denoising algorithm uses the correlation coefficient to select intrinsic mode function (IMF) components obtained from the CEEMDAN decomposition. The IMFs, which are more closely related to the original signal, are selected. Then, the wavelet thresholding denoising algorithm is applied to each of the selected IMFs to perform additional denoising. For each IMF component, specific threshold values are calculated based on their frequency and amplitude characteristics. Subsequently, the wavelet coefficients of the IMF components are processed by using these threshold values. Finally, the denoised IMF components are combined and reconstructed to obtain the final denoised signal. Applying the wavelet threshold denoising algorithm to IMF components can effectively remove noise components that cannot be removed by traditional CEEMDAN partial reconstruction methods. By using the threshold value calculated based on the characteristics of each IMF component, the wavelet thresholding denoising process is improved in comparison with directly using a single threshold value. This approach enhances the algorithm’s adaptability and enables more effective removal of noise from the signal.</sec><sec>We apply the proposed method to underwater ranging experiments. A 532 nm intensity-modulated continuous wave laser is used as a light source. Ranging is performed for a target in water with varying attenuation coefficients. A white polyvinyl chloride (PVC) reflector is used as a target. When the correlation extreme value is directly used to determine the delay at a distance of 3.75 attenuation length, it results in a ranging error of 19.2 cm. However, after applying the proposed method, the ranging error is reduced to 6.2 cm, thus effectively improving the ranging accuracy. These results demonstrate that the method has a significant denoising effect in underwater lidar system.</sec>

Backward scattering suppression in an underwater LiDAR signal processing based on CEEMDAN-fast ICA algorithm.

A new signal-processing method to realize blind source separation (BSS) in an underwater lidar-radar system based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and independent component analysis (ICA) is presented in this paper. The new statistical signal processing approach can recover weak target reflections from strong backward scattering clutters in turbid water, thus greatly improve the ranging accuracy. The proposed method can overcome the common problem of ICA, i.e. the number of observations must be equal to or larger than the number of sources to be separated, therefore multiple independent observations are required, which normally is realized by repeating the measurements in identical circumstances. In the new approach, the observation matrix for ICA is constructed by CEEMDAN from a single measurement. BSS can be performed on a single measurement of the mixed source signals. The CEEMDAN-ICA method avoid the uncertainty induced by the change of measurement circumstances and reduce the errors in ICA algorithm. In addition, the new approach can also improve the detection efficiency because the number of measurement is reduced. The new approach was tested in an underwater lidar-radar system. A mirror and a white Polyvinyl chloride (PVC) plate were used as target, respectively. Without using the CEEMDAN- Fast ICA, the ranging error with the mirror was 12.5 cm at 2 m distance when the attenuation coefficient of the water was 7.1 m-1. After applying the algorithm, under the same experimental conditions, the ranging accuracy was improved to 4.33 cm. For the PVC plate, the ranging errors were 5.01 cm and 21.54 cm at 3.75 attenuation length with and without the algorithm respectively. In both cases, applying this algorithm can significantly improve the ranging accuracy.

Evaluating Responses by Sympatric Ungulates to Fence Modifications Across the Northern Great Plains

ABSTRACTAcross North America, incentive programs have assisted landholders with the construction of fences, often considered “wildlife friendly,” to assist in grazing management, which has resulted in a proliferation of fencing on the landscape. Many suggested “wildlife‐friendly” fence modifications have not been evaluated for their effectiveness on the targeted species or evaluated to assess consequences for nontarget species. We evaluated the effects of 2 modifications aimed to increase fence visibility (sage‐grouse [SAGR] reflectors and white polyvinyl chloride [PVC]) on the fence‐crossing behavior of 3 sympatric ungulates in the Northern Great Plains. We used trail cameras from 2016 to 2018 to capture images of pronghorn (Antilocapra americana), mule deer (Odocoileus hemionus), and white‐tailed deer (O. virginianus) at sites before and after fence sections were modified and compared crossing success by the 3 ungulates with that achieved at unchanged control sites. We used generalized linear modeling and a time‐to‐event approach to test the effect of fence modifications on ungulate crossing behavior. Our results showed that both SAGR reflectors and white PVC pipe did not impede fence‐crossing behaviors for either pronghorn or deer, nor was there a time lag in use of sites observed after modifications were deployed. Though we did not alter the height of the bottom wire, there was enough variability in bottom wire height between sites that our results indicate a greater probability of successful crossing by all 3 ungulates as bottom wire height increased. We recommend implementation of both SAGR reflectors and white PVC pipe because our results demonstrate no substantial unintended consequences on the crossing behavior of pronghorn and deer. © 2020 The Authors.Wildlife Society Bulletinpublished by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Development of dry-origin latent footwear impression on non-porous and semi-porous surfaces using a 5-methylthioninhydrin and L-alanine complex

5-methylthioninhydrin (5-MTN) is an amino acid sensitive reagent used for the development of latent fingermarks deposited on porous surfaces such as paper and wood. The present study demonstrates that the 5-MTN can be used as a latent footwear impression enhancement reagent, by reacting with trace multivalent metal ions, which are the main components of the latent footwear impression. 5-MTN and L-alanine complex (MTN-ALA) used for the latent footwear impression development was prepared, by mixing 4.5×10 −3 M 5-MTN (in methanol) and 4.5×10 −3 M L-alanine (in methanol) in 1:1 ratio, and keeping undisturbed at room temperature for 24 h. The latent footwear impressions were deposited on white and black non-porous surfaces (glass plate, polyethylene panel, polypropylene panel, acryl panel, polyvinyl chloride (PVC) panel, poly(methyl methacrylate) (PMMA) panel, acrylonitrile-butadiene-styrene (ABS) panel, tile), and a semi-porous surfaces (painted wood). The latent footwear impressions on these surfaces were treated with MTN-ALA complex by spraying. The fluorescence of footwear impressions (occurred due to the reaction between MTN-ALA and metal complexes) was observed under a 505 nm forensic light source and an orange barrier filter. The enhancement of latent footwear impression was achieved from black surfaces without any blurring. However, the fluorescence (enhancement) of footwear impression was not observed on the white PVC, PMMA, and ABS surfaces, because the incident light interfered and reflected on the surface. The sensitivity of MTN-ALA was superior to 2,2’-dipyridil, which is a representative non-fluorescing footwear impression enhancement reagent, and similar to 8-hydroxyquinoline, which is a representative fluorescing footwear impression enhancement reagent.

Photopinking of white PVC products: A kind of magic

Short‐term photoeffects like photograying, photobluing, and photopinking are well‐known in the polyvinyl chloride (PVC) industry. While photobluing and photograying are well understood regarding their mechanisms of occurrences there are still some missing facts. Furthermore, there are three different types of pinking effects with three different mechanisms and consequently three different ways to avoid this discoloration of mainly white PVC products. The recent paper is focusing on one hand of the photopinking of PVC products, which are stabilized with nitrogen‐containing, organic stabilizer whose mechanism was not explained until today. In the past there was neither a method to analyze nor to simulate this type of photopinking. However, the discovery of a charge transfer complex between the nitrogen‐containing substance and nitric acid gave the basic idea to investigate this phenomenon by photo‐electromotive force investigations of titanium dioxide and the nitrogen‐containing substance and by cyclo voltammetry. On the other hand, the authors are attempting to supplement the findings regarding the mechanism of the photopinking of white window profiles which are lead stabilized and which were installed north‐facing in cooler areas with high humidity. Again, a simulation and the analysis of the color‐giving substance of the north‐faced photopinking were impossible in the past. The authors assumed that antioxidants might play an important rule for this type of discoloration. They supported their hypothesis by synthesis of quinoid structures based on antioxidants, spectroscopic investigations, artificial weathering, and electrochemical calculations. J. VINYL ADDIT. TECHNOL., 24:195–207, 2018. © 2016 Society of Plastics Engineers

The effect of white or grey PVC pipe and its joint solvents (primer and cement) on odour problems in drinking water distribution systems

A study of the production of odour-causing compounds was conducted from the leaching of polyvinylchloride (PVC) pipe and its joints, primer and cement, into drinking water distribution systems. Flavour Profile Analysis (FPA), closed-loop stripping analysis--gas chromatography/mass spectrometry (CLSA-GC/MS) and sensory-GC analysis of white or grey PVC alone found no odour-causing compounds produced during the leaching experiments. FPA analysis of the PVC's primer and cement leached alone and/or when applied to grey or white PVC pipes produced a glue/varnish odour. A sweet/phenolic odour replaced the glue/varnish odour after the leached media were diluted with Milli-Q water to threshold odour intensity. Three compounds were responsible for the sweet/phenolic odour and were observed by sensoryGC analysis. The leaching study of the PVC pipe with its joint solvents (primer and cement) concluded that the original solvent compounds, and their reaction products that formed during the bonding process on the PVC pipe, were a primary source of the glue/varnish odour. The original compounds of the PVC primer and cement were not detected by CLSA-GC/MS, due to their high volatility during the CLSA extraction method and/or these compounds appeared in a solvent peak of the GC/MS analysis. However, the original primer and cement chemicals (acetone, tetrahydrofuran, methyl ethyl ketone, and cyclohexanone) had a glue/varnish odour. A total of nine odorous GC peaks were produced as reaction products from leaching of primer in water and white or grey PVC pipe with primer and cement, and white or grey PVC with primer only. None of these compounds were among the chemical ingredients in the original primer or cement. Four GC peaks with a sweet/phenolic odour were present due to the reaction products of the cement leached with white or grey PVC. None of these compounds were positively identified.

Use of PVC Pipe Refugia as a Sampling Technique for Hylid Treefrogs

We used retreats made from white polyvinyl chloride (PVC) pipes to capture hylids and determined how pipe design and placement influenced the frequency with which hylids used pipes as retreats. Pipes were hung vertically in trees on three sites in north-central Florida. Pipes were checked twice weekly for 10 mo during which 788 individuals of four species (Hyla squirella, H. cinerea, H. femoralis and H. gratiosa) were captured, with 2658 recaptures. Retreats on hardwoods were used significantly more than retreats on pines, and retreats hung at 2 m and 4 m aboveground were used significantly more than retreats at 0 m. Long and T shaped retreats (both 60 cm long) were used significantly more than short (30 cm) retreats. Retreats capped on the bottom with water inside and 3.81 cm in diameter were used more frequently than retreats of the same diameter that were either capped on the top or not capped and retreats 1.75 cm in diameter with no cap.