Foam Sheets Research Articles

EXPERIMENTAL AND NUMERICAL INVESTIGATION OF A DOUBLE PASS SOLAR AIR HEATER PROVIDED WITH POROUS ABSORBER PLATE FOR DRYING APPLICATIONS

This investigation integrates experimental and numerical approaches to study a novel solar air heater aimed at achieving an efficient design for a solar collector suitable for drying applications under the meteorological conditions of Iraq. The importance of this investigation stems from the lack of optimal exploitation of solar energy reaching the solar collector, primarily attributable to elevated thermal losses despite numerous designs employed in such solar systems. Consequently, enhancing the thermal performance of solar collectors, particularly those employed in crop drying applications, stands as a crucial focal point for researchers within this domain. Two identical double-pass solar air heaters were designed and constructed for this research. Two types of copper foam sheets with different pore densities, specifically 10 PPI and 40 PPI, were used as absorber plates. The novel solar air heater was compared with a conventional solar air heater equipped with a flat absorber plate based on thermal performance. The effects of the mass flow rate, the air gap of the solar collector, and solar irradiation were examined on various parameters, including the outlet air temperature, solar collector efficiency, and pressure drop across the solar collectors. The results demonstrated that the double-pass solar air heater equipped with a 10 PPI porous absorber plate exhibited superior thermal performance compared to both the double-pass solar air heater with a 40 PPI absorber plate and the conventional absorber plates. Consequently, it can be considered suitable for drying applications. Furthermore, a comparison of the experimental findings with the results obtained from previous studies showed a good agreement.

Myosotis alpestris potential for extracting metal ions during wastewater pre-treatment at ore-mining facilities

Phytoremediation and phytoextraction are seen as promising technologies which facilitate the development research on obtaining transgenic plants capable of metals hyperaccumulation. The article is devoted to the assessment of the possibilities of using Alpine forget-me-not for industrial wastewater treatment.The experiment was conducted on the industrial site of the Kovdorski GOK (Kovdor Ore-Mining Integrated Works), owned by the EuroChem Group. In 2020-2021 we assessed the content of heavy metals in plants on phyto-rafts made in the form of rectangular sheets of polyethylene foam with slots for plants. The rafts were fixed in running water at the beginning of the outlet channel, through which wastewater is discharged after primary purification. The most intensive accumulation in the organs of Alpine forget-me-nots appeared to be for physiological or essential metals, which is explained by their physiological role and the presence of membrane mechanisms for their intensive absorption. In terms of hyperaccumulation criteria, we can refer it in relation to iron, magnesium and manganese, especially when calculated for dry mass.

Experimental and numerical studies on corrosion-resistant aluminium foam sandwich panel subject to low-velocity impact

Aluminium foam sandwich panels (AFSPs) have a high impact resistance and are suitable for a wide range of engineering applications. To improve corrosion resistance, this paper proposes an anti-corrosion sandwich panel with stainless steel as the upper sheet. Drop hammer impact tests were performed on a total of ten AFSPs to investigate their dynamic response and failure patterns. To assess the deformation performance of AFSPs, a laser displacement meter was used to obtain the bottom centre displacement. The effects of the impact energy and the thickness of each component of AFSPs on the peak impact force and deformation performance were studied. Test results showed that the thickness of each component had notable effects on the impactor and bottom displacements. In addition, the effect of the unit mass of the components in AFSPs on decreasing the bottom displacement was discussed. Compared to increasing the aluminium foam and lower sheet thicknesses, increasing the upper sheet thickness was more effective in decreasing the bottom displacement. A finite element model of AFSPs was developed to conduct parameter analysis, indicating that impactors with larger diameters resulted in higher peak forces and reduced deformation of AFSPs.

A Realistic Ingeniously Designed Cleft Palate Simulator for Training of Residents: Bridging the Gap Between Theory and Practice.

Cleft palate is a congenital deformity that presents significant challenges in surgical correction. Proper training with an educational model for can greatly enhance the learning curve and improve patient outcomes. This article discusses the development and evaluation of an economical cleft palate model designed to enhance surgical skills and confidence among residents. The model was constructed using dental casts, acrylic resin, foam sheets, double-sided adhesives, infant feeding tubes, and red dye. Tertiary care center. Surgical residents. The assembly time and material costs were recorded. To evaluate its effectiveness, participants' feedbacks were collected and analyzed. The cleft palate model was produced at a cost of 250 INR per unit, with assembly taking approximately 15 minutes. Overall, 32 residents completed the simulation exercise of cleft surgery on the model. Participants gave the model an average score of 4 (±0.60) for realistic anatomical appearance, 3.5 (±1.3) for replicating the tactile nature of human tissue. Anatomical accuracy and ability to manipulate tissue and perform suturing received a rating of 3.4 (±1.1) and 3.7 (±0.81), respectively. The model's value as a training tool scored 4.4 (±0.51), with an overall satisfaction rating of 4.6 (±0.22) among residents. Our cleft palate model offers an economical, practical, and accessible solution for surgical training. This model is a viable alternative to more complex and expensive training tools and potentially enhancing the training of healthcare professionals in cleft palate repair.

Numerical investigation of surface and volume thermal imaging of nickel-graphene foam sheets by finite element method

The detailed theoretical analysis of heat equations is applied to Nickel foam specimens with various pore-size coated graphene thin film of 200 nm thickness under laser excitation. 2D and 3D thermal numerical models were proposed by applying the finite element method. To explain the proposed numerical model, the influence of discretization parameters and the heat diffusion length were studied. The proposed model accurately predicts the thermal spreading in the specimens. The numerical model showed the sensitivity of the model for the structure variation to achieve an accurate thermal imaging when the used laser is of radius value is within of specimen pore size and modulated at low frequency.

Sustainable active packaging developed using starch-based foam incorporating 1-Methylcyclopropene@α-Cyclodextrin

The preservation of fruit freshness during long-distance transportation frequently faces significant challenges, especially a high risk of spoilage. 1-Methylcyclopropene (1-MCP), an effective ethylene inhibitor, is widely used to slow down fruit ripening and maintain freshness. However, achieving a controllable release of 1-MCP is challenging, and traditional carrier materials such as paper, chitosan films, and microcapsules have proven unsatisfactory. Here, we introduced an innovative sustainable packaging featuring a “sandwich” structure based on starch-based foam sheets. The hydrophilic properties and porous structure of the foam ensure the controllable and slow release of 1-MCP. Additionally, its mechanical durability provides a cushioning role to minimize physical damage to fruits during transport process. This method achieves a significant reduction in ethylene production and respiration rates by up to 60.49 % and 57.50 % respectively, leading to an extension of the shelf life of climacteric fruits by 5–10 days. The novel active packaging not only effectively prolongs the shelf life and improves the quality of fruit but is also economical and environmentally friendly due to its biodegradable starch-based composition.

The effects of ACR/MAH ionic cross-linking on the cell morphology, mechanical properties, and dimensional stability of PVC foams

This study details a novel approach to enhance the dimensional stability of foamed polyvinyl chloride (PVC) materials through the introduction of a reversible cross-linking network. This is achieved via the carboxylation of acrylate polymers (ACR) utilizing the hydrolysis reaction of maleic anhydride (MAH) during the extrusion of PVC foam sheets. Subsequently, an ionic cross-linking network is formed using calcium-zinc (Ca-Zn) stabilizers. This paper elucidates the process of cell formation and the mechanisms underpinning the ACR/MAH ion network formation. Cell morphology of the foamed PVC was characterized using SEM, and the effects of ionic cross-linking on the plasticizing time, dimensional stability, and mechanical properties were analyzed through cell diameter distribution measurements and rheometry. The longitudinal and transverse dimensional shrinkage of PVC-F/MAH1 was reduced by 28.0 % and 28.9 %, respectively. The construction of the ACR/MAH ion cross-linking network not only augments the mechanical properties but also substantially enhances the dimensional stability of the material. This approach underscores the viability of ion cross-linking networks in advancing the performance parameters of PVC foams, suggesting a promising avenue for future research and development in polymer processing technology, and potentially expanding their application spectrum.

Sound absorption and thermal insulation materials from waste palm oil for housing application: Green polyurethane/water hyacinth fiber sheet composite

This research presents an eco-friendly method for producing polyurethane foam (PUF) and water hyacinth fiber (WHF) sheets. The objectives were to engineer wall materials with sound-absorption and thermal insulation capabilities while also improving the mechanical properties of pure PUF. Waste palm oil (WPO) was successfully utilized as a polyol substrate, playing a substantially role in PUF generation, acting as a PU binder, and serving as a PU adhesive. The productions of PUF (NCO index of 100) combined with WHF sheets (WHF/PU binder ratio of 60/40) using four distinct fabrication methods (sheet-foam-sheet (SFS), foam-sheet-foam (FSF), foam-foam-foam (FFF), and sheet-sheet-sheet (SSS)) were investigated with a fabrication thickness of 150 mm. The findings indicate that the SFS configuration demonstrates remarkable sound absorption properties, with an average sound absorption (SAA) of 0.59, noise reduction coefficient (NRC) of 0.39, and the highest sound absorption coefficient (SAC) of 0.93 at 1900 Hz, alongside a thermal conductivity of 0.0301 W/mK. Importantly, all four methodologies produce SAC values greater than 0.4, outperforming commercial counterparts while demonstrating low thermal conductivity indicative of effective thermal insulation. The result noted that WHF sheet exhibited self-extinguishing properties, making them suitable for use in construction materials. As a result, SFS emerges as the best method for constructing superior sound absorption and thermal insulation materials. This study emphasizes the potential of waste derived WPO and WHF as advantageous eco-friendly substrates for industrial wall and housing materials.

Effect of oil concentration, viscosity, and surface tension on tube temperature and heat transfer coefficients of R1234ze(E)/oil spray evaporation on an enhanced tube bundle

Shell-and-tube evaporators are widely used in desalination, refrigeration, and petrochemical industries. The heat transfer process in spray-type evaporators combines the droplets impingement at the top rows of the bundles and falling film evaporation for the bottom rows, with a transitional region in the center of the bundle. Spray evaporators are a promising alternative to flooded-type shell and tube heat exchangers because they run with significantly lower refrigerant charge amounts.This study presents new data for the spray evaporation of low-GWP refrigerant/oil mixtures on an enhanced tube bundle. The experiments involved R134a (HFC) and R1234ze(E) (HFO) paired with synthetic Polyolester (POE68 and POE220) lubricants. The tests utilized a boiling enhanced tube (re-entrant cavity tube) and were conducted at saturation temperatures of −6.7 °C, 2.2 °C and 10 °C (20°F, 36°F and 50°F), with heat flux varying from 3 to 35 kW/m2 and oil circulation ratio (OCR) ranging from 0.4 % to 2 %. With the addition of oil, the bundle heat transfer coefficient (HTC) of refrigerant/oil mixtures decreased by 20–50 % at an OCR of 1.2 % and a heat flux of 13.5 kW/m2, across the tested saturation temperatures. The average wall superheat across the bundle exhibited at least a 48 % increase for all the refrigerant/oil mixtures tested at an OCR of 1.2 %. The viscosity of the refrigerant/oil mixture showed a limited influence on heat transfer compared to surface tension, mainly because the oil concentrations were quite small. Oil promoted a partial dry-out of the tubes, especially at the bottom of the bundle. Foaming was observed and increased with heat flux and oil concentration. Foam sheets on the tube bundle created an additional barrier for the liquid refrigerant to reach the tube heat transfer surfaces and thus decreased the overall bundle heat transfer coefficient.

Revolutionizing Foam Cutting Efficiency in Indonesia with AutoCAD

Foam set machines are essential for cutting foam sheets in various industries, including furniture, textiles, and foam manufacturing. PT. Amangriya, using a custom foam set machine for two years, identified the need for efficiency improvements. This research aimed to enhance the foam set machine's design using AutoCAD software. Key improvements included an automatic top clamp, a flexible side clamp, and reduced machine dimensions. These modifications resulted in a more efficient and compact machine, facilitating easier manufacturing and assembly processes. The study highlights the potential for significant efficiency gains in the foam manufacturing industry through design enhancements. Highlight: Enhanced machine design with AutoCAD software improves efficiency and functionality. Key modifications include automatic top clamp and flexible side clamp. Reduced machine dimensions facilitate easier manufacturing and assembly. Keywoard: Foam set machine, design enhancement, efficiency, AutoCAD, manufacturing

Design and application of a testing device for solar reflective materials

Using white polyvinyl chloride pipes, gray polyvinyl chloride pipes, natural rubber foam sheets, and nylon 6 as experimental materials, this article designed a sandwich structure solar reflective material testing device. By testing the thermal conductivity of various materials and the thermal conductivity of the composite materials in the device and conducting thermal insulation verification experiments on the solar reflective material testing device, it was found that the overall thermal conductivity of the device was small and the internal temperature of the device was less affected by the external environmental temperature. The results indicated that the solar reflective material testing device has good insulation performance.

The Effect of Packaging Types on Fresh Peaches in the Direct‐To‐Consumer Environment: Distribution Testing, Life Cycle Assessment and Economic Impact

ABSTRACTThe direct‐to‐consumer (D2C) shipping mode presents new opportunity for fresh peach sales in North America where demand over the past four decades has steadily declined. The hazards in this distribution mode are severe, and fresh peaches are fragile emphasizing the need for proper protection. A full analysis that not only encompasses the effects of the D2C distribution environment but also incorporates analyses of the environmental and economic impact of the packages utilized for transit of peaches is necessary. In this study, we use the metrics of peach grade, firmness, soluble solids concentration and percent softness before and after the distribution simulation to compare the protective performance of six DTC packaging systems. All six packages consist of a single layer corrugated box with varying primary packaging. A life cycle analysis of each package system is performed as well as an economic analysis on the packaged materials and cost to ship. We conclude that peach damage in shock testing is related to the freedom of movement that peaches have within each package type and varies by package system. All the package types evaluated amplify input vibration in the frequency range commonly associated with the input from the tires of truck‐trailer systems. There are no statistical differences between package systems in the distribution simulation of the six package types except in peach softness and grade of melting flesh peaches. Finally, we found that a reduction in material use and change in format, that is, foam sheets to foam netting, provides for sufficient peach protection while reducing environmental and economic impact.

Thermal insulation box design for maintaining cool temperature and the postharvest quality of okra

Postharvest loss of okra is caused by its high respiration rate and temperature fluctuations in the supply chain. To address this, five thermal insulation boxes were designed, combining different materials, and evaluated for okra quality during simulated transportation and storage. The treatments included the standard foam box, metalized foam sheet (two layers consisting of aluminum foil and expanded polyethylene), prototype-A (three layers consisting of dual layer of aluminum foil and expanded polyethylene), prototype-B (four layers consisting of aluminum foil, nonwoven, expanded polyethylene, and aluminum foil), and standard regular slotted container. Material tests revealed that aluminum foil and expanded polyethylene had the lowest thermal heat energy. The composite sandwich box design, prototype-A, demonstrated the highest maximum insulation time of 28 h and thermal resistance of 0.332 m2°C/W. Prototype-A and prototype-B effectively maintained low temperature fluctuation, minimized air and okra temperature changes, and maintained 6.19 to 8.25 % CO2, which was within an acceptable range of 4–10 % for okra. Both prototypes exhibited reduced percentage mass loss in okra below 5 %. Importantly, both prototypes demonstrated the lowest incidence of okra pod surface browning and maintained the quality for 6 d, surpassing metalized foam sheet and standard regular slotted container. These findings offer sandwich design with 3 or 4 layers as promising alternatives for thermal insulation boxes in cold chain management, enhancing the transport packaging of okra under ambient environments compared to the standard foam box.

Recyclable Cu-based monolith catalysts for peroxymonosulfate-activated degradation of organic dyes

The development of monolith catalysts with high reusability for the advanced oxidation processes targeting water-pollution remains a big challenge. In this work, we prepared a series of Cu-based monolith catalysts by simply calcining metallic Cu foam or Cu sheet under different temperatures. Performance of the monolith catalysts was evaluated in degradation of Methylene Blue or Orange II with peroxymonosulfate as oxidant. The monolith catalyst is more efficient at higher pH of the reaction medium, and can be used at least 20 cycles without loss of the degradation activity. Based on the characterizations of XRD, XPS and EPR, the active composition of the catalysts for the degradation is ascribed to CuO, and the active radicals generated during the degradation process are speculated to be O2•–, ·OH, SO4•– and 1O2.

Modulating ultrasound field phase and amplitude using foam gratings as an alternative to acoustic lenses

There is an increasing number of applications for therapeutic ultrasound, including high intensity focused ultrasound surgery, neuromodulation and drug delivery. For many of these applications, accurate focusing of the ultrasound field at tissue depths of several cm is essential and thus patient-specific acoustic lenses have been widely investigated as an economical alternative to phased array transducers. Lenses can be cast or 3D printed from a range of polymers offering good acoustic impedance matching to human tissue. Disadvantages of polymer lenses, however, include their relatively large size and the difficulties involved in eliminating gas bubbles during production. In this study an alternative approach is investigated using a “grating” comprising a sheet of polymer foam, perforated with a series of pores that act as wave guides. The grating is placed in front of a transducer with the pores arranged to modulate the phase and amplitude of the sound field as required. The gratings can be cheaply and rapidly fabricated, are < 5 mm thick and can achieve phase changes of more than 180° were successfully achieved while maintaining a transmission amplitude of more than 50%.

Effect of temperature on post-yield behavior of PVC foams

Experiments were conducted on Divinycell HCP30 foam to develop equations predicting its elastic and post-yield behavior from − 40 to + 60 °C. In these experiments, the foam was subjected to post-yield cyclic tension, compression and shear and monotonic biaxial tension and compression loading in the environmental chamber of an MTS servo-hydraulic machine. Elastic modulus and yield strength of the foam were found to decrease linearly with increasing temperature and could be expressed by a single equation in terms of room temperature properties. Post-yield behavior involved plasticity, viscoelasticity, and damage. An elastic–plastic viscoelastic damage model was used to predict post-yield behavior of the foam at different temperatures. Temperature dependent plastic hardening and viscoelastic damage functions were extracted from the experimental results and used to simulate elastic and post-yield stress–strain behavior in ABAQUS Explicit using a user-defined material subroutine. The ABAQUS user-defined material was validated with experiments on Divinycell HCP30 foam sheets at various temperatures. Good comparisons were found between ABAQUS and experimental results.

Novel Ag-Cu foam sheet with multi-layer composite structure for high performance joining of SiC power chips

Novel Ag-Cu foam sheet with multi-layer composite structure for high performance joining of SiC power chips

A novel semi-continuous preparation mode of ultra-low density thermoplastic polyurethane foam

The production of elastomer foam commonly faces challenges like low production efficiency, limited controllability, uneven foaming, and inherent shrinkage characteristics, especially in manufacturing thick foam sheets. Addressing these, this study introduces innovative “semi-continuous foaming with ultra-low-pressure” (SFU) strategy that integrates low-temperature gas-locking, conduction-microwave heating, and N2-assisted gas-exchange, aimed at optimizing the entire process of TPU foam production, from manufacturing and storage to post-processing. The low-temperature gas-locking scheme realizes semi-continuous preparation of elastomer foam; the conduction-microwave heating scheme significantly improves the heating speed and uniformity; and the N2-assisted gas exchange scheme prevents elastomer foam shrinkage, facilitating the creation of high expansion ratio foam. This process offers the flexibility to adjust initial cell sizes (5–30 μm after shrinkage) and expansion ratios (1–24 times) by manipulating parameters such as microwave radiation time, power, and saturation time. Furthermore, the foam was prepared under ultra-low pressure (<7 MPa), resulting in a final expansion exceeding 14.2 times TPU thick sheet (5 mm thickness before foaming) foam with excellent resilience (energy loss coefficient ∼ 10 % and ball resilience ∼ 68.8 %). This study explores the mechanism by which TPU can self-absorb during microwave heating and extends this process to TPU materials with varying thicknesses (16.5 mm thickness before foaming) and chain compositions, as well as different types of elastomeric materials or materials with elastomer-like properties (e.g., PBAT, etc.). The SFU strategy not only significantly reduces energy and gas consumption but also steers the technological advancement of foam production towards a greener and more sustainable future.

An easy-to-use platform for colorimetric determination of dextran: A potential application for the sugar industry

A user-friendly platform based on foam sheets and silica solid support was developed for colorimetric sensing of dextran via phenol–sulfuric acid assay. The chemical reagents, sulfuric acid and phenol were separately preserved by silica gel. The brown color product of the phenol–sulfuric acid reaction occurred on the silica solid support when sample solutions were added. The color intensity of brown products was easily obtained by a smartphone and color processing software. Subsequently, a broad concentration range of dextran could be determined up to 10,000 mg/L dextran, with a detection limit of 360 mg/L. Furthermore, a precision study, including inter-day and intra-day studies, presented a satisfactory performance for dextran detection. The developed platform was successfully applied for the sugar industry's dextran determination of syrup samples.

The survival of murine hepatitis virus (a surrogate of SARS-CoV-2) on conventional packaging materials under cold chain conditions.

The cold chain conditions have been suggested to facilitate long-distance transmission of SARS-CoV-2, but it is unclear how viable the virus is on cold chain packaging materials. This study used the MHV-JHM strain of murine hepatitis virus as a model organism to investigate the viability of SARS-CoV-2 on foam, plastic, cardboard, and wood sheets at different temperatures (-40°C, -20°C, and 4°C). In addition, the ability of peracetic acid and sodium hypochlorite to eliminate the MHV-JHM on plastic and cardboard sheets were also evaluated. The results indicate that MHV-JHM can survive on foam, plastic, or cardboard sheets for up to 28 days at -40°C and -20°C, and up to 14 days on foam and plastic surfaces at 4°C. Although viral nucleic acids were still detectable after storing at 4°C for 28 days, the corresponding virus titer was below the limit of quantification (LOQ). The study highlights that a positive nucleic acid test result may not indicate that the virus is still viable, and confirms that peracetic acid and sodium hypochlorite can effectively eliminate MHV-JHM on packaging materials under cold chain conditions.