Plastic Sheet Research Articles

A virtual fields method for identifying anisotropic elastic constants of fiber reinforced composites using a single tension test: Theory and validation

A novel inverse identification method using only a single tensile specimen for obtaining four anisotropic elastic constants of fiber reinforced composites sheet is proposed in this study. The method is based on virtual fields method (VFM) for solving weak form equilibrium equation with an optimized tension-type non-standard specimen specially designed with an elliptic hole at the center of the specimen (though not limited to this special shape). Full-field strain measured by a digital image correlation (DIC) technique is applied as experimental strain fields which are used as inputs of the VFM. For optimizing the tension-type VFM specimen, finite element (FE) analysis is conducted as a virtual experiment to generate ideal strain fields. The determined tension-type VFM specimen has an elliptic hole with 45° inclined to the loading direction, which is optimized from the error analysis between the FE input and VFM calculated material constants. For the validation of the proposed approach, experiments are performed with unidirectional carbon fiber reinforced plastic (UD-CFRP) sheets. The comparison of VFM identified anisotropic constants to those determined from the standard tensile tests with three different orientated samples shows satisfactory accuracy ranging between −5.94 and 0.71%, errors which confirm the validity of the new inverse method for the characterization of anisotropic elasticity of composites sheets.

Wide-range spectral measurement of radiative properties of commercial greenhouse covering plastics and their impacts into the energy management in a greenhouse

Controlling a greenhouse microclimate requires energy consumption for heating and cooling the greenhouse inside air. The radiative heat transfer process inside a greenhouse depends on the spectral radiative properties of different components especially on the greenhouse covering material. There is a lack of information about the precise spectral radiative properties of the available commercial plastic sheets used as greenhouse covers. In this research, the spectral radiative properties of several commercial greenhouse covers are measured in a wide wavelength range from 0.2 to 28 μm. The measured properties are then used in a developed model to simulate the indoor climate of a greenhouse. In the developed model, the covering material is treated as a semi-transparent medium, the soil surface is considered as partially reflective surface, and the inside air is assumed as an absorbing-emitting medium. Finally, under a specific hourly climate conditions, the impacts of using different commercial covers on heating and cooling load demands are investigated. The measured total solar transmittance was 70.3–92.1% and the long wave transmittance was 18.1–61.8% for selected samples. The results indicated that using the appropriate covering plastic reduced the annual cooling load by 9.8% and heating load by 6.3%.

Experimental investigation of fire-exposed steel tubular stub columns wrapped with CFRP sheets

This paper investigates the effect of high temperature (600 °C, 800 °C, 1000 °C and 1100 °C) and the layers of carbon fibre reinforced plastics (CFRP) sheets (one, two, three, four) on the behaviour of fire-exposed steel tubular stub columns. Forty specimens were tested to investigate the failure modes, ultimate bearing capacity under axial compression, load-strain relationship, load-displacement relationship and initial stiffness of the specimens. Ultimate bearing capacity and initial stiffness decrease with the increase of temperature. The ultimate bearing capacity and ductility of fire-exposed specimens wrapped with CFRP sheets increase with the increase of CFRP sheets layers. After being strengthened by CFRP sheets with the same number of winding layers, circular steel tubular (CST) stub columns obtained a greater load-bearing capacity increase than square steel tubular (SST) stub columns. The largest enhancement of the ultimate bearing capacity of fire-exposed specimens is 59.47%. A recommended formula for the calculation of ultimate bearing capacity of fire-exposed specimens wrapped with CFRP sheets is proposed.

First Report of Botryosphaeria dothidea Causing Leaf Spot and Wilt on Celtis sinensis in China.

Celtis sinensis Pers. (Chinese hackberry), belonging to the family Ulmaceae, is widely used as a street tree or landscape plant because of its longevity and aesthetic growth habit. Additionally, C. sinensis is of economic importance due to its medicinal properties. Roots and bark of the plant can be used in natural medicine for the treatment of lumbago, measles, tumor, etc (Zhang et al. 2016). In July 2019, symptoms of leaf spot were observed on C. sinensis in Yuanshan national forest park of Zibo, Shandong Province, China (36.48°N, 117.84°E). We surveyed more than 500 square meters of forest area, and more than 80% of the acreage was affected with the leafspot disease. Symptoms on infected leaves appeared as regular round or oval spots, colored in yellow with brown borders, which coalesced into larger spots as the disease progressed. To investigate the cause, 20 leaves of infected tissues were cut into ~2 mm pieces and surface disinfected with 75% ethanol for 30 s, rinsed three times with sterile deionized water. These were air dried and placed on potato dextrose agar (PDA) and incubated at 25℃ for 5 to 7 days. A minimum of 15 isolates were obtained and cultures were initially white, gradually becoming gray green to dark after 1 week, producing copious amounts of gray aerial mycelium. Three representative single isolates were used for molecular identification, which were verified based on the amplification of DNA sequences of internal transcribed spacer region, translation elongation factor 1 alpha and beta-tubulin genes, using the primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999), and BT-2a/BT-2b (Glass and Donaldson 1995), respectively. The sequenced genes (GenBank accession no. MT367874, MT385087, MT374083) exhibited 99.63% (Identity=545/547), 99.00% (Identity=297/300), and 100.00% (Identity=451/451) homology with the corresponding genes of type specimen of Botryosphaeria dothidea strain CBS110302 (GenBank accession no. AY259092, AY573218, EU673106), respectively. Morphological and molecular results showed that the isolates were B. dothidea (Slippers et al. 2014; Zhai et al. 2014). Pathogenicity was confirmed using five living, healthy C. sinensis plants with three leaves were wound inoculated with mycelial plugs (about 4 mm in diameter) of B. dothidea from a 7-day-old culture grown on PDA, while inoculated with sterile PDA plugs on the same leaves were served as negative controls. All the plants were covered by plastic sheeting and keep high relative humidity by adding water in time. Seven days later, all inoculated leaves appeared as round dark brown spots, which were larger than observed in the field. The pathogenicity test was repeated three times. No symptoms were observed on negative controls. Fungi re-isolated from inoculated leaves were confirmed as B. dothidea on the basis morphology and molecular characterization as described above. To our knowledge, this is the first report on the presence of B. dothidea affecting C. sinensis plants in China. This discovery is important to ensure the sustainable production of C. sinensis, an important landscaping and medicinal tree.

Fracture mechanism and strength evaluation of Al5052/CFRP joint produced by coaxial one-side resistance spot welding

Carbon fibre reinforced plastics (CFRP) and Al5052 sheets were joined by coaxial one-side resistance spot welding (COS-RSW). The cross-section features and mechanical behaviour of the joints in single lap shear (SLS) test were investigated. The underlying joining mechanism was found to be the NCO covalent bond between silane coupling agent and CFRP via the X-ray photoelectron spectroscopy (XPS) analysis. The joints of low welding current exhibited interfacial fracture with low strength and small displacement during the SLS test, while the joints of high welding current presented a staged failure process with tearing of the CFRP, which gave higher strength and larger displacement. The bonding zone was divided into three subzones, which showed specific surface morphologies and distinct contributions to the load-bearing capacity of the joint. The joining strength showed a positive correlation with welding current until the occurrence of decomposition in CFRP, which reduced the area of effective bonding zone and played a negative effect on strength.

Letter: Considerations for Performing Emergent Neurointerventional Procedures in a COVID-19 Environment.

Letter: Considerations for Performing Emergent Neurointerventional Procedures in a COVID-19 Environment.

Multilayer Graphene Battery Anodes on Plastic Sheets for Flexible Electronics

Anode structures on plastic sheets are essential for next-generation flexible rechargeable batteries. Graphite films, i.e., thick multilayer graphene (MLG), are promising anode materials; however, ...

Pulsed THz imaging for thickness characterization of plastic sheets

The thickness of 2, 4, 6, 8, 10, and 12 mm thick polycarbonate (PC) and poly-methyl methacrylate (PMMA) sheets were characterized nondestructively by terahertz time-of-flight tomography in reflection. Due to terahertz attenuation and dispersion in the material, first characterized in transmission, features in the reflected signal associated with structure deep in the sample (i.e., the back interface) may be difficult to identify, and therefore signal processing is employed, namely frequency-wavelet domain deconvolution and a cross-correlation approach in which we account for dispersion. The refractive indices are found to be n(ν)=1.67−0.0096vfor PC and n(ν)=1.61−0.0085vfor PMMA, while the absorption coefficients, which follow the form of the universal dielectric response, are αν=0.564+9.075v1.669 for PC and αν=0.0406+13.66v1.776 for PMMA, where ν is measured in THz and the absorption coefficient is in units of cm−1. We show that straightforward analysis techniques that neglect dispersion are limited to measuring layer thicknesses in these materials of less than ~17 mm, while accounting for dispersion results in a factor-of-two improvement, allowing us to measure samples as thick as ~36 mm.

Techniques to verify the correct skin areas for biopsy, treatment, recurrence and in-vivo dosimetry using an A4 plastic sheet as template

Introduction Radiotherapy (RT) is a precise treatment usually given over multiple sessions with millimetre accuracy to the planned target. Patients undergoing RT require verification of the target area prior each treatment. Imaging with kilovoltage X-rays is usually used to verify the treatment volumes of solid internal tumours, but this process is unsuitable for skin cancers as it cannot visualise skin marks. When biopsying or treating skin cancers, there is a chance that other nearby benign skin structures can be confused with the lesion of concern. Templates using transparent sheets have been used to verify the treatment area. We present a series of cases to demonstrate our skin cancer verification technique using the humble A4 plastic sheet protector. Case series: Case 1 details the use of a plastic sheet template to correctly identify lesions that require biopsy. Cases 2 and 3 describe how templates are used for in-field verification prior to electron and superficial RT treatment, respectively. Case 4 shows how stored templates can be used to quantify recurrence. Conclusion: For skin cancer planning and verification, the A4 plastic sheet protector is easy to use, reproducible, economical and storable. It serves multiple purposes: to delineate areas of biopsy and treatment, to discover whether a recurrence is in-field or not, and to also verify where in vivo dosimetry should be measured.

Springback Behavior of Fiber Metal Laminates with Carbon Fiber-Reinforced Core in V-Bending Process

Fiber metal laminates (FMLs) are a kind of hybrid composite material that consist of metal sheets and fiber-reinforced composite layers. The use of FMLs has been particularly increasing in the production of aircraft bodies. However, the springback behavior that occurs during the formation of FML parts has a negative impact on the form of the final product. In the present study, FMLs were manufactured by combining aluminum 5754-H22 sheets and carbon fiber-reinforced plastic sheets by using adhesive. A set of experiments were performed to determine the effect of bending angle, face sheet thickness and core thickness on the springback behavior of FMLs. The results showed that the amount of springback in the FML specimen increased as the bending angle increased. It was found that when the thickness of the face sheet increased, the amount of springback in FML specimens was higher in all bending angles. In addition, the amount of springback in FML specimens decreased as core thickness increased.

Living with COVID-19 pandemic – Emerging challenges for ultrasound physicians and their suggested solution

Background: The recent coronavirus disease (COVID-19) pandemic is a serious health concern with far-reaching implications in every facet of human life. New challenges have emerged for ultrasound physicians engaged in diagnostic ultrasound examinations.
 Methods: Based on a comprehensive literature review the author has suggested a few precautionary measures that should be incorporated by the ultrasound physicians in their practice against the spread of coronavirus disease.
 Suggestions: Multi-level safeguard checks before, during, and after the ultrasound examination are suggested to protect ultrasound physicians, staff, and patients from COVID-19. The importance of triage for patient screening is stressed. Also, limiting patients by deferring non-urgent cases and cancelling aerosol-generating procedures is recommended. The need of counselling of patients and staff is stressed regarding the importance of facemasks, hand hygiene, and safe distancing. Incorporating different types of barriers against the virus such as facemasks, face-shields, personnel protective suits for ultrasound physicians and staff, and shielding the equipment and transducer with disposable or wipeable plastic sheets is suggested. Besides, the significance of cleaning and disinfection of the examination room and equipment by suitable disinfectants after each patient and at the end of the day is highlighted. 
 Conclusion: Learning to live with the COVID-19 pandemic is the need of the day both for the general public and medical community. Being members of the medical community ultrasound physicians should gear up to the emerging challenges of COVID-19 to protect themselves, their patients, and allied healthcare staff from coronavirus infection.

Mini thermoforming semi-auto machine for teaching and learning

Mini Thermoforming Semi-Auto Machine is a product-making machine from heated plastic sheets. This machine uses a vacuum suction method to form a product that you want to produce. This machine is designed to help and facilitate learning and teaching matters in higher education institutions where the use of this machine can reduce costs especially maintenance costs if damaged. The size of the machine is 600 mm x 500 mm which is one per fourth of the actual size in the plastic manufacturing factories. Some testing of machines and products is done. Among them is the test of lifting frame which shows the time taken for the upward movement is 4 seconds and 3.5 seconds to decrease. In addition, stress tests are also performed where the product can be perfectly formed when inhaled by vacuum. In terms of temperature the test is done by heating on the sheet or plastic sheets. The last test was made on the product, where the product was produced perfectly within 3 minutes and the temperature was 240° C. With the creation of this Mini Thermoforming Semi-Auto Machine, it is hoped that the learning and teaching process in institutions of higher learning will work better as this machine provides comfort in terms of size and prioritizes the safety of lecturers and students and is able to produce products in a short time.

Evaluation of Noise Absorption Capacity of Various Materials

Noise absorption and transmission property of materials is of great importance in order to determine the amount of noise transmitted from source to receiver. Unwanted noise can cause various biological and psychological effects to humans and other organisms in nature. This paper deals with the experimental study on noise absorbing and deflecting ability of various available materials. These materials could be utilized in industrial complexes and building construction applications for noise level reduction purposes. The materials such as glass, plywood, thermocol (scientifically known as polystyrene), fiber plastic sheet and coconut fiber sheet have been used in the experiment as a noise barrier. Through experimental analysis, the reduction noise level was obtained in terms of decibel (dB), sound power level and loss of sound energy using hand held noise analyzer. The finding suggests that thermocol has the best sound absorbing capacity at medium to low sound pressure levels, whereas glass has the best sound absorbing capacity at high sound pressure levels.

Non-similar solution of Sisko nanofluid flow with variable thermal conductivity: a finite difference approach

PurposeThe main purpose of this study is to present a non-similar analysis of two-dimensional boundary layer flow of non-Newtonian nanofluid over a vertical stretching sheet with variable thermal conductivity. The Sisko fluid model is used for non-Newtonian fluid with an exponent (n* > 1), that is, shear thickening fluid. Buongiorno model for nanofluid accounting Brownian diffusion and thermophoresis effects is used to model the governing differential equations.Design/methodology/approachThe governing boundary layer equations are converted into nondimensional coupled nonlinear partial differential equations using appropriate transformations. The resultant differential equations are solved numerically using implicit finite difference scheme in association with the quasilinearization technique.FindingsThis analysis shows that the temperature raises for thermal conductivity parameter and velocity ratio parameter while decreases for the thermal buoyancy parameter. The thermophoresis and Brownian diffusion parameter that characterizes the nanofluid flow enhances the temperature and reduces the heat transfer rate. Skin friction drag can be effectively reduced by proper control of the values of thermal buoyancy and velocity ratio parameter.Practical implicationsThe wall heating and cooling investigation result in the analysis of the control parameters that are related to the designing and manufacturing of thermal systems for cooling applications and energy harvesting. These control parameters have practical significance in the designing of heat exchangers and solar thermal collectors, in glass and polymer industries, in the extrusion of plastic sheets, the process of cooling of the metallic plate, etc.Originality/valueTo the best of authors’ knowledge, it is found from the literature survey that no similar work has been published which investigates the non-similar solution of Sisko nanofluid with variable thermal conductivity using finite difference method and quasilinearization technique.

The nasal tent: an adjuvant for performing endoscopic endonasal surgery in the Covid era and beyond.

PurposeTo propose a cost-effective reproducible barrier method to safely perform endoscopic endonasal surgery during the Covid-19 pandemic.MethodsThis manuscript highlights the use of a clear, cost-effective disposable plastic sheet that is draped as a tent over the operating area to contain aerolization of particles. This is then connected to a suction to remove airborne particles and thus reduce transmission of the virus.ConclusionThe use of a nasal tent is a simple and affordable method to limit particle spread during high-risk aerolisation procedures during the Covid era and beyond.

The application of evidence-based bundle approach to reduce surgical site infection in geriatric hip fracture patients: A single centre experience

Introduction: Surgical site infection (SSI) is associated with increased morbidity and mortality, prolongation on length of hospital stay and cost of community healthcare. In 2010 and 2012, our centre experienced an unexpectedly high rate of SSI in geriatric hip fracture patients with hemiarthroplasty done. A multifaceted intervention programme – ‘bundle approach’ – consisting of preoperative microbiological screening, perioperative measures and postoperative wound care was implemented. Method: Preoperative methicillin-resistant Staphylococcus aureus (MRSA) screening was implemented. Intravenous vancomycin was given as prophylactic antibiotic of choice in those patients with positive MRSA screening. All patients will be bathed with chlorhexidine lotion 1 day before operation or on the day of operation. Standardized protocol of surgical site disinfection was implemented: a stringent first stage povidone-iodine disinfection, second stage waterproof extremity draping and sterile plastic sheet wrapping of non-surgical region and third stage ChloraPrep, followed by circumferential iodophor-impregnated plastic adhesive drape (‘Ioban’) covering the hip and thigh region. The surgical wound was dressed with Aquacel adhesive tape after wound closure. Results: The total numbers of infected cases were 17 from 2008 to 2012 and 9 from 2013 to 2018 (first quarter). The rates of infection were 7.02% from 2008 to 2012 and 3.16% from 2013 to 2018 (first quarter). There was a statistically significant reduction in the number of infected cases of hemiarthroplasty after the implementation of bundle approach ( p = 0.0411). Discussion: The bundle approach showed to achieve an effective and sustained decrease in SSI for the geriatric hip fracture patients.

Easy and Accessible Protection against Aerosol Contagion during Airway Management.

The coronavirus disease 2019 (COVID-19) outbreak began in northern Italy in early February and quickly spread to the rest of the peninsula. It has been a major public health issue highlighting the challenges for the health system to quickly ramp up capacity in the face of a pandemic and in particular in accident and emergency departments, intensive care, and insufficient supply of critical equipment such as ventilators but also personal protective equipment. The shortage of personal protective equipment not only puts medical professionals’ lives at risk (at the time of writing more than 60 Italian doctors have died as a result of COVID-19) but also increases the risk of contagion within the hospital. Although elective surgery has been reduced, emergency surgery has continued and thus so has general anesthesia, without availability of the necessary protection. The inability to know which patients have COVID-19 in an emergency setting where tests kits are scarce, response times to test are slow, and with shortages or rationing of personal protective equipment requires the medical team to act as though the patient is positive unless proven otherwise, even though asymptomatic. In this scenario our team has trialed an easy and accessible technique to protect the operator/anesthetist from predictable aerosol during oxygen mask ventilation, intubation, and extubation. Our patients arrived in the operating room wearing a surgical mask. The primary anesthetist has always strictly followed the correct doffing and donning procedures before and after intubation with surgical mask, goggle/visor, double gloves, and gown, not the appropriate personal protective equipment because of the shortage we faced at the beginning. After anesthesia induction, 3 min breathing 100% oxygen, propofol 2 mg/kg was given to put the patients asleep to avoid the sensation of being smothered. Once the patient was asleep we positioned the transparent plastic sheet over the chest and head fixed with a tape to the abdomen (fig. 1). Fentanyl 2 mcg/kg and rocuronium 0.6 mg/kg were given. Patients were ventilated in oxygen mask under the transparent plastic sheet while the anesthetist was above, away and protected from any aerosol coming from the patient. Only the operator hands with double disposable gloves were under the transparent sheet. The intubation was performed with a video laryngoscope (King Vision, Ambu, Denmark) under the transparent plastic sheet stuck to the king vision screen with the operator moving his hands under the plastic cover. Once the intubation was assessed, the plastic sheet was removed by rolling it inward from the head to the abdomen, keeping the contaminated part inside, and then disposed in an appropriate biohazard container. A meticulous disinfection of the contaminated body parts (head, neck, and torso) was performed after intubation, and the drape underneath the head was replaced with a clean one.1 During the extubation a new transparent plastic sheet was positioned again as per the intubation phase, and endotracheal aspiration was performed without difficulty followed by extubation. Oxygen mask spontaneous ventilation was then delivered under the plastic cover until the coughing risk had passed and full posteanesthesia recovery and oxygenation was assessed. To date we have used this technique in eight cases without difficulty and no doctor contagion. In one of these cases the patient was diagnosed as COVID-19–positive three days after surgery despite the fact that two previous nasopharyngeal swabs were negative. When the result of the third swab came back positive, the anesthetist and the entire surgical and nursing team underwent nasopharyngeal swabs which were negative to the COVID-19, even though they were not wearing the appropriate personal protective equipment had the patient been positive before entering surgery. Despite further investigations needed to understand and assess the benefits of this simple, easy, accessible, and cost-effective technique to prevent any kind of aerosol risk during mask ventilation, intubation, and extubation maneuvers, we suggest it to prevent contagion during airway management in all patients throughout the COVID-19 outbreak if personal protective equipment are not available.Support was provided solely from institutional and/or departmental sources.The authors declare no competing interests.

What Are the Challenges and Complications of Sterilizing Autografts with Liquid Nitrogen for Malignant Bone Tumors? A Preliminary Report.

What Are the Challenges and Complications of Sterilizing Autografts with Liquid Nitrogen for Malignant Bone Tumors? A Preliminary Report.

Endotracheal intubation with barrier protection

Given the high risk of healthcare worker (HCW) infection with COVID-19 during aerosol-generating medical procedures, the use of a box barrier during intubation for protection of HCWs has been examined....

The growth performance and survival rate of catfish (Clarias sp.) that given probiotic controlling nitrogen

The water quality can be improved by using probiotics as bioremediation. The probiotics are a consortium of nitrification and denitrification bacteria (Pseudomonas aeruginosa and Achromobacter insuavis), which both of the indigenous bacteria are the products of the Research Institute for Freshwater Aquaculture and Fisheries Extension (RIFA). The objective study is to determine the adding frequency of RIFA probiotic into the water fish pond of catfish culture concerning growth performance and survival. The catfish fingerling with a size of 7-8 cm long and weighing 16.45 ± 0.3 g was used. The stocking density was 750 fish/pond. Nine plastic sheet ponds with a water volume of 1.6 m3 and completed with aeration were used. A dose of probiotics was 10 mL/m3. The difference in adding the frequency of probiotic as a treatment was as followed: A) every 5 days; B) every 10 days, and C) without probiotics. The parameters measured survival rate (SR), absolute weight growth, specific growth rate (SGR), feed conversion ratio (FCR), water quality. One way ANOVA with three treatments and three replications were performed. The results showed that the use of probiotics could control nitrogen compounds in catfish cultivation, where the frequency of administration every 5 days gives the best results.