Polycarbonate Plates Research Articles

Effect of polycarbonate and agricultural film on production and biochemical compounds of tomato fruits

Tomato production has been enhanced significantly by management using intervention of temperature and radiation control in a protected environment. The use of plastic and/or polycarbonate covers changes the dynamics of production in tropical climate regions. The present study aimed to compare the following covered cultivation conditions: 1) polycarbonate plate (10 mm) box-shaped polycarbonate with a twin wall with anti UV-A and B (P), 2) agricultural film (AF) anti UV-A and UV-B, and 3) open field (OF) on the productivity and quality of Italian hybrid tomatoes. The study was carried out at Embrapa Agrossilvipastoril located in Sinop, Mato Grosso, Brazil. Four tomato hybrids and 03 distinct environments were used in a randomized block design in a subplot setup with five replications. The main factor was hybrid traits, and the subplots were environments with different covers. The highest productivity occurred in the P environment, with the hybrids Fascinio and Vedette with 66.64 and 55.84 t ha-1, respectively. The highest plant yield obtained was in the P environment, with an average of 3.15 kg per plant. Among the evaluated hybrids, the highest antioxidant potential was observed in Shanty, and for the content of carotenoids, lycopene, and vitamin C, no significant difference was observed between the evaluated hybrids. We can conclude that the use of polycarbonate plates box shaped with a twinwall or agricultural film in a protected tomato cultivation system under high temperature conditions increases the yield and qualitative potential of the Fascinio and Vedette hybrids.

Rupture Nucleation on a Periodically Heterogeneous Interface

AbstractIn this study we explore experimentally the effects of fault heterogeneity on the rupture nucleation. We conducted friction experiments between two polycarbonate plates, with a periodically heterogeneous friction interface. The rupture propagation is monitored with an ultra‐fast video camera by taking advantage of the photo‐elastic properties of the material used. We show that the nucleation process does not always consists of a monotonic growth of the rupture velocity. Instead, the rupture front advances with an alternation of slow and fast episodes that accelerates until it reaches a point at which fast propagation dominates. This complex nucleation process is compared to the results predicted by previous numerical studies on heterogeneous interfaces. Finally, we test whether it is possible to describe this complex nucleation process as a homogenized nucleation. We also point out a large variability in the rupture process due to the uncontrolled stress heterogeneity that occurs during the loading process.

Failure analysis on abnormal cracking of polycarbonate plates used in the gearbox oil level gauge for high-speed train

The gearbox of bogie is the core transmission component of the high-speed train. Once its parts have problems, this will cause hidden danger to the running of the train. Therefore, the safety of the gearbox parts must be paid special attention. The failed samples studied in this paper were the polycarbonate (PC) plates used in the gearbox oil level gauge and seven PC plates were found failure during routine maintenance for a certain type of high-speed train. Among them, five plates had cracks parallel to the oil level and close to the middle area, while other two plates had cracks near the circular arc area and lay at an angle of 45° with the level line. In order to find out the root cause of their failure, a variety of material analysis methods were used to examine the properties of the materials, and the fracture morphologies were studied in detail by means of macro and micro observations. The analysis results show that the causes of the failed PC plates could be divided into two types, one was caused by environmental stress cracking and thermal fatigue and the other was caused by forced installation when the length of the PC plate was a little larger. According to the correct determination of the failure causes, the pertinent countermeasures like length reduction of the PC plate and spraying special transparent coating on the PC plate have been put forward, which have been proven very effective after execution.

Fast UV-Curable Zwitter-Wettable Coatings with Reliable Antifogging/Frost-Resisting Performances.

Antifogging surfaces with unique properties to migrate severe fog formation have gained extensive interest, which is of particular interest for transparent substrates to obtain high visibility and transparency. To date, a large number of strategies including superhydrophilic or superhydrophobic surfaces and titanium dioxide (TiO2)-based composite coatings have been developed based on different mechanisms. Although these surfaces exhibit effective antifogging properties, the rigid nanostructures, cumbersome preparation, and the need for UV light excitation largely limit their widespread applications. Herein, we report a zwitter-wettable antifogging and frost-resisting coating through a fast UV-curable cross-linking of copolymer with benzophenone groups. A series of random copolymers consisting of hydrophilic hydroxyethyl methacrylate (HEA), hydrophobic methyl methacrylate (MMA), and benzophenone-based acrylate units are developed by thermally triggered free-radical polymerization. Upon UV light irradiation, a highly efficient antifogging/frost-resisting coating is covalently bonded on a polycarbonate plate surface, maintaining a light transmission higher than 85%, which was confirmed in both high and low temperature anti-fog tests. Moreover, the wetting behaviors reveal that the antifogging performance exhibited by the zwitter-wettable surface mainly relies on its surface water-adsorbing capability to imbibe condensed water vapor on the surface outmost layer. Notably, the antifogging/frost-resisting behaviors can be well regulated by adjusting the hydrophilic/hydrophobic units, due to the proper balance between the water-adsorption and coating stability. Owing to its simplicity, low-cost preparation and high efficiency, this UV-curable acrylate antifogging coating may find a wide range of applications in various display devices in analytical and detection instruments.

Analysis of Anisotropic Elastic Medium with Multiple Elliptical Holes Subjected to Uniform Load of in-Plane and Out-of-Plane Shear at Infinity

In this paper, a stress concentration around two holes of a 3D-printed material and stress intensity factors (SIFs) at straight crack tips of a rock are shown graphically as several practical calculation examples. The stress components and SIFs are calculated using the two-dimensional elastic theory. The elastic constitutive equation of materials has been used as isotropy or orthotropy in most previous analyses. Consequently, the mutual influence of the in-plane and out-of-plane shear problem has rarely been discussed. Therefore, at the first in this paper, the solutions that take into consideration the general constitutive equation with such mutual influence, are derived by the modified Lekhnitskii formulation. Next, numerical calculations for a 3D-printed polycarbonate plate subjected to uniform tension are performed in order to evaluate the mutual influence of anisotropy on the stress concentration for two circular holes. By changing the distance between the holes and angle formed by the stack and tensile directions, not only the effect of these parameters on the magnitude of out-of-plane shear stress but also the stress concentration factor for tension are clarified. Further, SIF for fracture mode I is calculated for a straight crack group in granite, and the mutual influence of SIF for fracture mode III is evaluated. As the results, it is found about SIF for fracture mode III that it becomes zero for enough crack spacing, whereas it is increasing continuously with increase of crack density.

Culture-Free Quantification of Bacteria Using Digital Fluorescence Imaging in a Tunable Magnetic Capturing Cartridge for Onsite Food Testing.

Accurate, onsite detection of pathogenic bacteria from food matrices is required to rapidly respond to pathogen outbreaks. However, accurately detecting whole-cell bacteria in large sample volumes without an enrichment step remains a challenge. Therefore, bacterial samples must be concentrated, identified, and quantified. We developed a tunable magnetic capturing cartridge (TMCC) and combined it with a portable digital fluorescence reader for quick, onsite, quantitative detection of Staphylococcus aureus. The TMCC platform integrates an absorption pad impregnated with water-soluble polyvinyl alcohol (PVA) with an injection-molded polycarbonate (PC) plate that has a hard magnet on its back and an acrylonitrile-butadiene-styrene case. An S. aureus-specific antibody conjugated with magnetic nanoparticles was used to concentrate bacteria from a large-volume sample and capture bacteria within the TMCC. The retention time for capturing bacteria on the TMCC was adjusted by controlling the concentration and volume of the PVA solution. Concentrated bacterial samples bound to target-specific aptamer probes conjugated with quantum dots were loaded into the TMCC for a controlled time, followed by attachment of the bacteria to the PC plate and removal of unbound aptamer probes with wash buffer. The captured bacteria were quantified using a digital fluorescence reader equipped with an embedded program that automatically counts fluorescently tagged bacteria. The bacterial count made using the TMCC was comparable to a standard plate count (R2 = 0.9898), with assay sensitivity and specificity of 94.3 and 100%, respectively.

Streamer Propagation along Profiled Insulator Surfaces under Positive Impulse Voltages

Controlling discharge growth on insulator surfaces is important in high voltage gaseous insulation systems. In this study, the effect of small-scale surface profiles on streamer discharge propagation is examined experimentally. The experimental test objects were 5x72x150 mm polycarbonate plates with and without machined surface profiles. One test object had a surface with 0.5 mm deep semi-circular corrugations, while the other profile had 0.5 mm deep rectangular corrugations. The semi-circular profile increased the surface area with 20 %, while the rectangular profile increased the area with 110 %. A plain surface was also examined as a reference. Positive impulse voltages were applied to a 1 mm thick disk electrode placed 2 mm above the insulator. The insulator was placed in a grounded aluminium casing. The streamer development was imaged with a light-sensitive high-speed camera. Surface charges left on the surface after the impulse were examined using an electrostatic probe and simulations of saturation charge. The rectangular surface profile reduced the streamer range significantly, which suggests an effect of added surface area. Imaging indicated that the wavelike surface streamers follow the profiles closely. Surface potential measurements showed a saddle-shaped distributions, with values in line with saturation charge computations.

Spatial profile of Al-ZnO thin film on polycarbonate deposited by ring-shaped magnetized rf plasma sputtering with two facing cylindrical Al2O3 – ZnO targets

Radial profiles of the ion saturation current are measured in a ring-shaped magnetized radio-frequency plasma sputtering process with two facing cylindrical ZnO targets including Al2O3 (2% wt.). The profile has a non-uniform shape with a peak whose position corresponds to the target near the electrode due to the effect of the magnetic field distribution. It becomes uniform at large distances between the substrate and a target (d st ≥ 50 mm). The radial profile of the resistivity of the Al-ZnO (AZO) films deposited on a polycarbonate plate at Ar gas pressure of 0.27 Pa is uniform at about 10−3 Ω · cm for d st ≥ 50 mm. The films deposited at various positions and room-substrate-temperature also show a good crystallinity based on an X-ray diffraction peak of about 33.95–34.44°. The grains exhibit a preferential orientation along the [002] axis with its size ranging from 18.15 to 28.17 nm. A higher transmittance of 95.6% in the visible region is also obtained.

A comparative analysis on friction stir welding of similar and dissimilar polymers: acrylonitrile butadiene styrene and polycarbonate plates

A comparative analysis on friction stir welding of similar and dissimilar polymers: acrylonitrile butadiene styrene and polycarbonate plates

Influence of Tool pin Profiles in Friction Stir Welding of Aluminum Alloy and Polycarbonate

In this study, the impact of tool pin profile on the dissimilar joining characteristics of aluminum alloy AA2017 and polycarbonate in friction stir welding (FSW) was examined. The tool pins made of SKD11 tool steel were used in the experiments of the FSW to join AA2017 and polycarbonate plates in a butt configuration at a tool rotation speed of 1320 and 1760 rpm and tool transverse speed of 60 mm/min. The tool shoulder diameter and tool pin height were set to 10 mm and 2 mm. The shapes of tool pin were cylindrical with and without groove, tapered cylindrical with and without groove, bobbin shaped with and without groove, square, triangular, pentagonal, hexagonal, oval, and ellipsoidal. The measurement of axial force was performed using a dynamometer. The changes in workpiece temperature at six locations during the process were measured using K-type thermocouples embedded in the plates. Microstructures of welded joints were examined by an optical microscope. Vickers Microhardness mapping was performed in and around the weld nugget zone, which is formed by the material flow between the two different base materials. From the result, the grooved tool pins generated less heat; while cylindrical, square, and oval type pins are also result in the superior properties of the welds during joining processes. Each tool pin had unique material flow behavior and weld formation, and the weld defects such as tunnel/voids occurred at the joint interface. The oval tool pin gives rise to the highest joint efficiency at a higher tool rotation speed, and the ellipsoidal tool pin generates the highest joint efficiency at a lower tool rotation speed was noticed.

Effect of porosity of aluminum foam on welding between aluminum foam and polycarbonate plate during friction welding

Effect of porosity of aluminum foam on welding between aluminum foam and polycarbonate plate during friction welding

Force and Torque Perspective and Their Effects on the Mechanical and Microstructural Characteristics of Dissimilar Friction Stir Welded Acrylonitrile Butadiene Styrene and Polycarbonate Plates

Force and Torque Perspective and Their Effects on the Mechanical and Microstructural Characteristics of Dissimilar Friction Stir Welded Acrylonitrile Butadiene Styrene and Polycarbonate Plates

Dynamic photoelastic experimental study on the influence of joint surface geometrical property on wave propagation and stress disturbance

Rock joints significantly affect the dynamic response of rock masses and the stability of underground structures . In this study, the dynamic photoelastic test was conducted to investigate the influence of joints on the stress field and wave propagation . The photoelastic equipment as well as the Split Hopkinson Pressure Bar (SHPB) were adopted for the test. The specimen sandwiched between the input and output bars was composed of two polycarbonate plates. One side of the plates was uneven with a few notches, while other sides were smooth and flat. The artificial joints were simulated by the contact of the uneven and flat sides of the two plates. The relation between the stress wave propagation and the stress field around the joint was studied when the joint has different contact area ratios, joint thicknesses, and joint surface distributions. The test results show that compared to the joint thickness, the joint contact area ratio and the joint surface distribution have a significant influence on the wave propagation and stress field near the joint. The transmitted wave is highly correlative with the stress field. This work provides a beneficial attempt to reveal the stress field disturbance and the effect of joint geometrical properties on wave propagation from the photoelastic test.

Transparent polycarbonate coated with CeO2 nanozymes repel Pseudomonas aeruginosa PA14 biofilms.

Highly transparent CeO2/polycarbonate surfaces were fabricated that prevent adhesion, proliferation, and the spread of bacteria. CeO2 nanoparticles with diameters of 10-15 nm and lengths of 100-200 nm for this application were prepared by oxidizing aqueous dispersions of Ce(OH)3 with H2O2 in the presence of nitrilotriacetic acid (NTA) as the capping agent. The surface-functionalized water-dispersible CeO2 nanorods showed high catalytic activity in the halogenation reactions, which makes them highly efficient functional mimics of haloperoxidases. These enzymes are used in nature to prevent the formation of biofilms through the halogenation of signaling compounds that interfere with bacterial cell-cell communication ("quorum sensing"). Bacteria-repellent CeO2/polycarbonate plates were prepared by dip-coating plasma-treated polycarbonate plates in aqueous CeO2 particle dispersions. The quasi-enzymatic activity of the CeO2 coating was demonstrated using phenol red enzyme assays. The monolayer coating of CeO2 nanorods (1.6 μg cm-2) and the bacteria repellent properties were demonstrated by atomic force microscopy, biofilm assays, and fluorescence measurements. The engineered polymer surfaces have the ability to repel biofilms as green antimicrobials on plastics, where H2O2 is present in humid environments such as automotive parts, greenhouses, or plastic containers for rainwater.

Characterization of a Commercial Bioluminescence Tomography System for Pre-Clinical Radiation Research

<h3>Purpose/Objective(s)</h3> To advance image-guided irradiation for soft tissue targeting and treatment assessment, we collaborated with our industrial partner and developed a bioluminescence tomography system (BLT, MuriGlo) for pre-clinical radiation research. We characterize the system performance and demonstrate its capability in target localization for radiation guidance. <h3>Materials/Methods</h3> MuriGlo consists of four-mirror system, filters, lens and CCD camera, enabling a compact imaging platform and multi-projection and multi-spectral BLT. The imaging mouse bed includes a base, and a detachable and transportable bed, allowing animal imaged in MuriGlo and transferred to small animal radiation research platform (SARRP) for CBCT imaging and BLT-guided irradiation. A transparent polycarbonate plate covering the middle of the mouse bed is used to support and image animal at 180⁰ projection under the bed. We investigated its effects on optical signal acquisition, 3D BLT reconstruction accuracy and dosimetric impact. Imaging phantoms are designed to evaluate 2D imaging resolution, focal plane, depth of field, signal acquisition linearity, imaging uniformity and distortion. An optimization routine with pinhole camera model was developed to map 2D bioluminescence images (BLIs) to the surface of the numerical mesh of imaged object generated from the CBCT image. The mapped BLIs are used as input data for BLT reconstruction. Spectral derivative method with compressed sensing conjugate gradient algorithm was implemented for BLT volumetric reconstruction. To minimize the ambient temperature in affecting in vivo bioluminescence signal intensity and spectrum, a temperature control module was also developed to maintain consistent temperature in the MuriGlo imaging chamber. Phantom and glioblastoma (GBM) mouse model will be used to validate the localization accuracy of the BLT system for guidance. <h3>Results</h3> The depth of field of MuriGlo was measured at 24mm, and the focal plane is set at 16mm above the mouse bed to have clear surface BLIs of mouse at all projections. The linearity between signal and exposure time from 0.1 to 180s is within 0.6% deviation. Our initial test shows within a given region of interest, the image uniformity is within 5% variation and image shift due to distortion is within 0.25mm. The data mapping from the 2D BLIs to 3D CBCT image is within 0.6mm. With temperature control turned on, the imaging chamber could be warmed up to 37°C from room temperature in 13 mins. Our phantom test shows MuriGlo can localize 3D bioluminescent target at 1mm accuracy and only 0.2mm deviation was observed for the case with and without transparent plate. <h3>Conclusion</h3> This work is the first systematic study in characterizing the commercial BLT-guided system for pre-clinical radiation research. We expect the information and methods developed in this study will support MuriGlo users, cross different institutes, in performing accurate image-guided radiation research and facilitating study reproducibility.

Endothelial Injury in Diving: Atomic Force-, Electronic-, and Light-Microscopy Study of the Ovine Decompressed Blood Vessels.

We suggested that the nanobubbles, which appear at the active hydrophobic spots (AHSs) at the luminal aspect of the blood vessels, are the gas micronuclei from which the decompression bubbles evolve and the endothelial injury during the decompression is due to the tearing off the cell membranes with the detaching bubbles. Ovine blood vessels were stretched over the polycarbonate plates or glass microscopic slides and were exposed under saline to the hyperbaric pressure (1,013 kPa, 19 h). Following decompression, the blood vessels were photographed for the identification (by bubble formation) of the AHS. Nanobubbles could not be demonstrated at the AHS by using the atomic force microscopy (AFM) because of the roughness of the surface, which disabled the close contact of the probe. In the electron microscopy, no endothelial cells were observed in the samples from the area near to the AHS, but the underlying elastin layer of the intima was observed adjacent to the media. Some intact endothelial cells were observed only in the locations far from an AHS. In the optical microscopy, no endothelial cells were observed in the blood vessels in close proximity to the AHS and in some sections, debris or a detached cluster of the endothelial cells were observed. Intact endothelial cells could be found at the sites distant from an AHS. This study supports the assumption, where the detached bubbles tear off the endothelial cells and cause the initial endothelial injury following the decompression.

Measurements of S0 mode Lamb waves using a high-speed polarization camera to detect damage in transparent materials during non-contact excitation based on a laser-induced plasma shock wave

The demand for transparent materials has been expanding due to their ubiquity in products such as solar panels, tablet terminals, and smartphones. To mass produce high-quality products, quickly detecting damage on the µm scale and evaluating the quality are critical. Herein an Nd:YAG pulsed laser with a nanosecond order is used to generate a shock wave by laser induced plasma, which is subsequently used as a non-contact, non-destructive excitation force for transparent materials. Then, a high-speed polarization camera measures the generated Lamb wave. In this experiment, an impulse input is generated via a laser-induced plasma shock wave and the phase velocity of the generated Lamb wave in the polycarbonate plate is measured by a high-speed polarization camera. We found that this Lamb wave was in the S0 mode. Observing its propagation can detect scratches on the order of several hundred µm on the surface of a transparent plate in a non-contact, non-destructive manner.

Evaluating the Design and Repeatability of a Novel Device to Measure Friction of Mechanical Surrogate Skins in Contact with Cotton Textiles

The ability to measure the level of friction between the human skin and a given textile is critical across fashion and textiles sectors, not least for the development of sporting and protective clothing. A portable custom-made device capable of measuring friction during the skin-textile interaction across often difficult or impossible to investigate body regions with objective repeatability has been established. The friction between a pre-shrunk 100% cotton textile and a quantity of four control surfaces (transparent and patterned polycarbonate plastic, and silicon and lorica surrogate skin) was measured three times per day across five consecutive days. The results clearly demonstrated that the novel friction test device had an excellent repeatability of 0.94 and 0.93 intraclass corelation coefficient for static and dynamic friction coefficient measurement, respectively. The silicon surrogate skin control surface produced the highest friction coefficient, while the pattered polycarbonate plate demonstrated the lowest friction coefficient, suggesting that the physical features of the control surface material influenced the recorded coefficient of friction. It was also revealed that the relationship between the static and dynamic friction coefficient is dependent on the surface material.

Friction welding of porous aluminum and polycarbonate plate

Composite materials consisting of porous aluminum and resin are expected to meet the current demand for the weight reduction of parts. The objective of this study is to introduce friction welding for joining porous aluminum and a polycarbonate plate. The advantages of friction welding are that it is a simple process and the joining surface is locally and directly heated by the friction heat generated between the porous aluminum and the polycarbonate plate. We showed that joining of porous aluminum and a polycarbonate plate can be achieved by friction welding via the anchor effect without the collapse of pores. The observed joining strength was similar to the strength of the porous aluminum itself.

Numerical modelling study of a modified sandbag system for ballistic protection

Modern field fortification systems are very large and cause a logistical burden during setup, thus setting the requirement for their modification. A simulation study was conducted to study the correlation between the compaction of sand and the energy absorbed by it when impacted by a solid steel projectile at 850 m/s. Furthermore, the sandbag was modified by the addition of plates in the system to observe the change in projectile penetration and the energy absorption behaviour of the sand. The factors considered for this study were the plate thickness (15 mm, 25 mm), plate material (aluminium, concrete, plexiglass, polycarbonate, steel) and plate location (226 mm, 236 mm, 256 mm from the point of impact). It was observed that a layer of compressed sand is formed around the projectile, aiding the energy absorption and dissipation process during impact. Upon addition of the plate, it was observed that the modified system (plate and sand) absorbed maximum energy when the plate is placed closest to the point of maximum penetration without the plate. It was also noted that the addition of the plate enhanced energy absorption characteristics of the system compared to conventional sandbags because of increased compaction of sand. From the study, it was observed that the plexiglass and polycarbonate plates had the maximum energy absorption and maximum deformation. The steel plate had the least energy absorption and minimal deformation. Concrete and Aluminium had comparable areal density, energy absorption and lowest deformation, making them the preferred choice of plate material for a modified sandbag. The numerical studies were verified using a gas gun and a modified sandbag with Aluminium plates to show that the addition of a plate improves compaction behaviour of sand.