Acrylonitrile Butadiene Styrene Plastic Research Articles

Review and Assessment of Existing and Future Techniques for Traceability with Particular Focus on Applicability to ABS Plastics

It is generally recognized that the use of physical and digital information-based solutions for tracking plastic materials along a value chain can favour the transition to a circular economy and help to overcome obstacles. In the near future, traceability and information exchange between all actors in the value chain of the plastics industry will be crucial to establishing more effective recycling systems. Recycling plastics is a complex process that is particularly complicated in the case of acrylonitrile butadiene styrene (ABS) plastic because of its versatility and use in many applications. This literature study is part of a larger EU-funded project with the acronym ABSolEU (Paving the way for an ABS recycling revolution in the EU). One of its goals is to propose a suitable traceability system for ABS products through physical marking with a digital connection to a suitable data-management system to facilitate the circular use of ABS. The aim of this paper is therefore to review and assess the current and future techniques for traceability with a particular focus on their use for ABS plastics as a basis for this proposal. The scientific literature and initiatives are discussed within three technological areas, viz., labelling and traceability systems currently in use, digital data sharing systems and physical marking. The first section includes some examples of systems used commonly today. For data sharing, three digital technologies are discussed, viz., Digital Product Passports, blockchain solutions and certification systems, which identify a product through information that is attached to it and store, share and analyse data throughout the product’s life cycle. Finally, several different methods for physical marking are described and evaluated, including different labels on a product’s surface and the addition of a specific material to a polymer matrix that can be identified at any point in time with the use of a special light source or device. The conclusion from this study is that the most promising data management technology for the near future is blockchain technology, which could be shared by all ABS products. Regarding physical marking, producers must evaluate different options for individual products, using the most appropriate and economical technology for each specific product. It is also important to evaluate what information should be attached to a specific product to meet the needs of all actors in the value chain.

Sustainable strategies towards better utilization of synthetic polymers.

The abstract provides an overview of a study focused on analyzing diverse strategies to achieve sustainable utilization of synthetic polymers through effective waste management. The escalating global consumption of synthetic polymers has precipitated a concerning increase in plastic waste and environmental degradation. To address this challenge, novel materials with specified application goals, such as engineered plastic, have been developed and are intended for recycling and reuse. Despite the reuse and recycling, when plastic gets disposed into the environment, the degradation properties of plastics render a direct disposal hazard, posing a significant environmental threat. To mitigate these issues, the concept of replacing specific monomers of engineered synthetic plastics with bio-alternatives or blending them with other polymers to enhance sustainability and environmental compatibility has emerged. In this study, Acrylonitrile Butadiene Styrene (ABS) plastic is the focal material, and three distinct investigations were conducted. First, replacing ABS plastic's butadiene monomer with natural rubber was explored for its properties and environmental impact. Second, ABS plastic was blended with virgin, recycled, and bio-alternatives of PET (polyethylene terephthalate) and PVC (polyvinyl chloride) polymers. Lastly, recycled ABS blended with recycled PET and PVC was analyzed for mechanical properties. Comparative assessments of these blends were made based on mechanical properties, carbon emissions, and cost-effectiveness. The study determined that the r-ABS/r-PVC (recycled) blend exhibited the most favorable characteristics for practical application.

An Antimicrobial Copper-Plastic Composite Coating: Characterization and In Situ Study in a Hospital Environment.

A method has been proposed for creating an operationally durable copper coating with antimicrobial properties for the buttons of electrical switches based on the gas dynamic spray deposition of copper on acrylonitrile butadiene styrene (ABS) plastic. It is shown that during the coating process, a polymer film is formed on top of the copper layer. Comparative in situ studies of microbial contamination have shown that the copper-coated buttons have a significant antimicrobial effect compared to standard buttons. Analysis of swabs over a 22-week study in a hospital environment showed that the frequency of contamination for a copper-coated button with various microorganisms was 2.7 times lower than that of a control button. The presented results allow us to consider the developed copper coating for plastic switches an effective alternative method in the fight against healthcare-associated infections.

Evaluation of Bruising Susceptibility and Response of Pears under Impact Loading through Finite Element Analysis

Mechanical damage and bruising of fruit is a critical problem in the food industry. Minimizing brusing and damage can be achieved by designing energy-absorbing structures and packaging systems in order to ensure the long-term quality of fresh produce. The aim of this study is to investigate the response and bruise susceptibility of pears under impact loading conditions through finite element analysis (FEA) methods. In this paper, three impact heights (0.25 m, 0.5 m, and 1.0 m), four impact material surfaces (poplar wood, rubber, cardboard, and acrylonitrile butadiene styrene (ABS) plastic), two packaging sizes (standard 0.22″ and sandwich lattice 2.1″), and three impact design structures (rigid, corrugated, and honeycomb) are considered. Based on mesh sensitivity analysis, a mesh element of 1.5 mm was adopted for all simulations, assuring the accuracy of results and considering the trade-off between mesh size and computational time. The response surface analysis approach was utilized in order to develop predictive empirical models related to pear bruising. Results revealed that the rubber-based impact platform yielded minimal bruise susceptibility at all heights, while standard-sized corrugated cardboard performed best at a height of 0.25 m. Furthermore, single, double, and triple layers of packaging cardboard were tested. We observed that adding a second soft layer of corrugated cardboard reduced the stress on the pear by around 33%. However, adding a third layer only reduced stress by 5%. The 3D-printed honeycomb ABS has potential as protective packaging but would require further investigations and parameter optimization. Stacking multiple layers of cardboard on top of each other is a cost-effective solution that could improve damping and, therefore, ensure good quality and increase the shelf life of the fresh produce. This study will help decision-makers select the optimal energy-absorbing material for cushioning and packaging designs in order to improve the handling and post-harvesting logistics of fresh produce.

Mechanical and durability performance of concrete made using acrylonitrile butadiene styrene plastic from waste-EEE as a partial replacement of the coarse aggregate

This paper presents the findings of a study focused on assessing the mechanical strength, durability performance and microstructure of concrete produced using acrylonitrile butadiene styrene (ABS) plastic derived from waste electrical and electronic equipment as aggregate. Granulated waste ABS replaced the coarse natural aggregate by volume in proportions of 5%, 10%, 25%, 50%, 75% and 100%. All concrete mixes were cured by precarbonation followed by water curing to improve early-age concrete performance in addition to conventional water curing alone. Mechanical and durability indexing tests (oxygen permeability, water sorptivity and chloride conductivity) indicate reduced compressive strength and durability index with increased waste ABS aggregate replacements. Even so, mixes made using substitutions ≤ 75% waste ABS aggregate achieved the minimum compressive strength required for use in structural applications (fcu ≥ 25 MPa) and satisfactory durability performance at 28-days. Prediction models for reinforced concrete exposed to an inland environment suggest a cover depth of 60 mm and 30 mm for concrete made using 100% waste ABS subjected to water curing alone and precarbonation, respectively. In contrast, prediction models for mixes exposed to coastal regions require a cover depth of 80 mm when made using 25% waste ABS cured using water alone, while 100% waste ABS may be used when subjected to precarbonation curing. Statistical data indicate a strong correlation between the nature of the interfacial transition zone and the observed strength and durability performance.

An investigation on the influence of three-dimensional printing orientation on the tensile and flexural strength of polymer and plastic materials

In the present investigation, the influence of three-dimensional printing orientation (0 and 90 degrees) on the mechanical properties has been evaluated for acrylonitrile butadiene styrene plastic and polylactic acid polymer specimens. Further, results found the significant influence of printing orientation on tensile strength, yield strength, and flexural strength for acrylonitrile butadiene styrene and polylactic acid was between 17.80 (minimum) to 77.67% (maximum). The percentage difference between three-point bending finite element analysis and experimental results was 3.05% which exhibited the good prediction capability of the developed finite element analysis model.

Application of 3D printing technology for green synthesis of Fe2O3 using ABS/TPU/chlorella skeletons for methyl orange removal.

Photocatalysis is widely acknowledged as an efficient and environmentally friendly method for treating dye-contaminated wastewater. However, the utilization of powdered photocatalysts presents significant challenges, including issues related to recyclability and the potential for secondary pollution. Herein, a novel technique based on 3D printing for the synthesizing of iron oxide (Fe2O3) involving chlorella was presented. Initially, chlorella powders were immobilized within acrylonitrile butadiene styrene (ABS) and thermoplastic polyurethane (TPU) substrate plastics using melt extrusion technology. Subsequently, these composite materials were transformed into ABS/TPU/chlorella skeletons (ATCh40), through fused deposition molding (FDM) technology. The integration of Fe2O3 onto the ATCh40 (ATCh40-Fe2O3) skeletons was accomplished by subjecting them to controlled heating in an oil bath. A comprehensive characterization of the synthesized materials confirms the successful growth of Fe2O3 on the surface of 3D skeletons. This strategy effectively addresses the immobilization challenges associated with powdered photocatalysts. In photocatalytic degradation experiments targeting methyl orange (MO), the ATCh40-Fe2O3 skeletons exhibited a remarkable MO removal rate of 91% within 240 min. Under conditions where the pH of MO solution was maintained at 3, and the ATCh40-Fe2O3 skeletons were subjected to a heat treatment in a 150 °C blast drying oven for 2 hours, the degradation rate of MO remained substantial, achieving 90% removal after 6 cycles. In contrast, when the same synthetic procedure was applied to ABS/TPU (AT) skeletons, the resulting product was identified as α-FeOOH. The MO removal rate by the AT-α-FeOOH skeletons was considerably lower, reaching only 49% after 240 min. This research provided a practical approach for the construction of photocatalytic devices through the use of 3D printing technology.

Life cycle assessment of recycling high impact polystyrene and acrylonitrile butadiene styrene plastic from waste refrigerators

Recycling waste refrigerator plastics can effectively reduce waste accumulation and carbon emissions. This study firstly applied the combination of electrostatic separation and magnetic separation in the waste refrigerators production line to recycle High-impact polystyrene (PS) and acrylonitrile butadiene styrene (ABS) plastics. A cradle-to-gate LCA study of recycling plastic from waste refrigerators was conducted. A carbon emission accounting system for the life cycle of waste plastic recycling was established, each emission unit was identified, the environment impact was analyzed. The results show that disposing waste polyurethane (PU) has the great impacts on eco-toxicity, and the use of high-power machines and Kraft paper packaging has great impacts on resources. The greenhouse gas emission generated during the life cycle is 8.53 kg·CO2eq/kWh. The greenhouse gas emission by recycling1kg ABS and HIPS was 2.59 kg·CO2eq/kWh and 1.84 kg·CO2eq/kWh, which is 84.35% and 61.61% less than producing virgin ABS and HIPS plastic from petrochemical industry. From 2016 to 2030, recycling waste refrigerators can reduce the total of 6452.06 kt waste plastics and greenhouse gas emissions by 370,350 tons. This study provides a scientific basis for exploring waste plastic recycling strategies and promoting green transition of the plastic industry.

Analysis of Drying Front Propagation and Coupled Heat and Mass Transfer During Evaporation From Additively Manufactured Porous Structures Under a Solar Flux.

Drying front propagation and coupled heat and mass transfer analysis from porous media is critical for soil-water dynamics, electronics cooling, and evaporative drying. In this study, de-ionized water was evaporated from three 3D printed porous structures (with 0.41 mm, 0.41 mm, and 0.16 mm effective radii, respectively) created out of acrylonitrile butadiene styrene (ABS) plastic using stereolithography technology. The structures were immersed in water until all the pores were invaded and then placed on the top of a sensitive scale to record evaporative mass loss. A 1000 W/m2 heat flux was applied with a solar simulator to the top of each structure to accelerate evaporation. The evaporative mass losses were recorded at 15 min time intervals and plotted against time to compare evaporation rates from the three structures. The evaporation phenomena were captured with a high-speed camera from the side of the structures to observe the drying front propagation during evaporation, and a high-resolution thermal camera was used to capture images to visualize the thermal gradients during evaporation. The 3D-structure with the smallest effective pore radius (i.e., 0.16 mm) experienced the sharpest decrease in the mass loss as the water evaporated from 0.8 g to 0.1 g within 180 min. The designed pore structures influenced hydraulic linkages, and therefore, evaporation processes. A coupled heat-and-mass-transfer model modeled constant rate evaporation, and the falling rate period was modeled through the normalized evaporation rate.

Assessing the impact of anti-microbial showerheads on the prevalence and abundance of opportunistic pathogens in shower water and shower water-associated aerosols

Respiratory infections from drinking water-associated pathogens that can cause infections in the immunocompromised (DWPIs) are increasing, yet knowledge of DWPI aerosolization and if dynamics are DWPI-specific is lacking. Although there are several DWPI mitigation strategies, the use of antimicrobial showerheads is one of the easiest and most economical. There are many manufacturers and designs of antimicrobial showerheads that claim to remove microorganisms from shower water, yet all fail to assess efficacy in realistic conditions. In this study, a custom-built shower laboratory housing triplicates of three different showerheads (antimicrobial filter-based, antimicrobial silver-embedded and conventional acrylonitrile butadiene styrene plastic) were used to assess the physiochemical and microbial dynamics in shower water and respirable shower water-associated aerosols (1µm – 5 µm) over the course of 84 days. Collectively, findings from the study suggest that showerheads marketed as antimicrobial produce similar chemical and DWPI water quality to non-antimicrobial showerheads (p= >0.05) when operated under real-world conditions, however marked differences in the rare microbial community were present. In addition, although there were no differences in absolute DWPI abundance between showerhead type, each DWPI peaked in concentration at a different biofilm ages, suggesting that potential DWPI inhalation risk is DWPI- specific and influenced by the number of days of operation of the showerhead.

Parametric study on producing Fused Deposition Modelling filament made of recovered carbon black reinforced Acrylonitrile Butadiene Styrene plastics

Additive manufacturing is a process that makes three-dimensional object layer by layer. There are many different types of 3D printer and the most commonly used is Fused Deposition Modeling (FDM). There is a need for a new material for Acrylonitrile Butadiene Styrene (ABS) FDM filament to improve filament strength and reduce the usage of plastics. From literature, there are limited studies available on making 3D printer filament reinforced by recycled carbon black. The limitation hinders the potential of using this material in new applications. In this study, recycled carbon black powder (rCB) was added as a filler reinforcement to enhance the properties of ABS. Parameters considered in this study were percentage of filler weight loading and filler size. Tests and characterisation used in this study were tensile test, thickness test, surface roughness test, scanning electron microscopy, density test and water absorption test. There were improvements in mechanical properties such as tensile test and elasticity of the filament compared to the pure ABS plastic. The higher filler percentage can improve the elasticity of filament and lower filler percentage can improve the strength of the filament. The findings could help in improving marketability status and commercialisation potential of rCB reinforced ABS filament for FDM applications.

Optimisation of process parameters for dimensional stability in FDM

The fused deposition modelling (FDM) technique has been adopted in the present work to fabricate Acrylonitrile Butadiene Styrene (ABS) plastic components using input variables like layer thickness, orientation, infill rate and the number of shells. The dimensional geometrical changes of FDM printed built parts, that is, length, width and thickness variation, are optimised individually. Still, a confounding effect is found in the optimisation of individual responses. To overcome this issue, this study uses a fuzzy inference system as an artificially intelligent system. A fuzzy inference system transformed all the responses into one response, known as a multi-response performance index (MPI), and optimised the MPI coupled with Taguchi philosophy. The optimal parameter combination of FDM-printed ABS components for the slightest variation in length, width, and thickness was found to be layer thickness: 200 µm, orientation: 0°, infill rate: 20%,and the number of shells: 3. The significant parametric effect on the responses of FDM components was studied using analysis of variance, and the results reveal that orientation is the most influential parameter trailed by infill rate and the number of shells.

Mechanical response of asphalt steel plastic pavement structure based on finite element simulation and scale load test

To promote sustainable road engineering, the focus is on identifying low-carbon, eco-friendly, and durable materials and structures, as conventional options face performance limitations. Hence, within this paper, we introduce a novel pavement structure, referred to as ASP, which comprises an SMA-13 asphalt mixture, a Q345D steel plate, and acrylonitrile butadiene styrene (ABS) plastic. Initially, we performed a uniaxial compression test to analyze the dynamic mechanical properties and modulus parameters of both the SMA-13 asphalt mixture and ABS plastic. To further investigate the mechanical response of the ASP pavement structure under actual traffic load conditions, we constructed a 1/3-scale model and subjected it to MMLS3 accelerated loading tests to confirm the validity of the established finite element model and verify the performance of the structure. Finally, we developed a full-scale finite element simulation model of the ASP pavement structure and analyzed its mechanical response under loading. The results were then compared to those obtained from typical pavement structures. The results from the MMLS3 accelerated loading test show that both the asphalt and steel plate layers in the ASP pavement structure exhibit similar strain behavior, with consistent peak strains. The strain generated by the underlying structural layer dissipates more quickly in the transverse position, while the steel plate layer and underlying structural layer mainly support the strain generated by the asphalt surface layer. Results from the full-scale finite element simulations indicate that the strain and stress generated between the ASP pavement structure and typical pavement structures are similar. However, the bottom of the steel plate layer in the ASP pavement structure experiences significant three-dimensional and vertical shear stress. In addition, the allowable material value of the bearing layer in the ASP pavement structure, which consists of Q345D steel plate and ABS plastic, is less than 1% compared to the typical pavement structure. This characteristic enables effective transfer and support of the moving vehicle load, highlighting the significant advantages of using steel plate and plastic as pavement materials. To conclude, the ASP pavement's internal structure aligns effectively with real-world conditions, as demonstrated by its load-bearing layer's performance under vehicular loads. This innovative design significantly improves road durability and sustainability, positioning it as a choice for future road construction. These findings provide valuable insights for researching the mechanical response patterns within the ASP pavement's internal structure.

Study of parametric interaction during fused filament fabrication (FFF) using interpretive structural modelling (ISM) followed by experimental analysis

PurposeFused filament fabrication (FFF) is a type of additive manufacturing (AM) based on materials extrusion. It is the most widely practiced AM route, especially used for polymer-based rapid prototyping and customized product fabrication in relation to aerospace, automotive, architecture, consumer goods and medical applications. During FFF, part quality (surface finish, dimensional accuracy and static mechanical strength) is greatly influenced by several process parameters. The paper aims to study FFF parametric influence on aforesaid part quality aspects. In addition, dynamic analysis of the FFF part is carried out.Design/methodology/approachInterpretive structural modelling is attempted to articulate interrelationships that exist amongst FFF parameters. Next, a few specimens are fabricated using acrylonitrile butadiene styrene plastic at varied build orientation and build style. Effects of build orientation and build style on part’s ultimate tensile strength, flexure strength along with width build time are studied. Prototype beams (of different thickness) are fabricated by varying build style. Instrumental impact hammer Modal analysis is performed on the cantilever beams (cantilever support) to obtain the natural frequencies (first mode). Parametric influence on natural frequencies is also studied.FindingsStatic mechanical properties (tensile and flexure strength) are greatly influenced by build style and build orientation. Natural frequency (NF) of prototype beams is highly influenced by the build style and beam thickness.Originality/valueFFF built parts when subjected to application, may have to face a variety of external dynamic loads. If frequency of induced vibration (due to external force) matches with NF of the component part, resonance is incurred. To avoid occurrence of resonance, operational frequency (frequency of externally applied forces) must be lower/ higher than the NF. Because NF depends on mass and stiffness, and boundary conditions, FFF parts produced through varying build style may definitely correspond to varied NF. This aspect is explained in this work.

Investigation of mechanical properties of rattan and bamboo fiber reinforced vinyl ester composite material for automotive application

In scope of this research, manufacturing and mechanical characterization of rattan and bamboo fiber reinforced vinyl ester composite material were carried out. Bamboo and rattan fiber was extracted by using retting process followed by chemical treatment to enhance mechanical properties. The composite was manufactured using bidirectional fiber mat in vacuum bag molding and hand layup process. The weight fraction between reinforcement and matrix was 24% and 76% respectively. Three types of composites were manufactured; Bamboo Fiber Composite (BFC), Rattan Fiber Composite (RFC), and Rattan (12%) and Bamboo (12%) Fiber Composite (RBFC). Different mechanical behavior of the composite was investigated, such as tensile strength, flexural strength, hardness, and impact strength. The maximum flexural and impact strength was found for RBFC with 57.66 MPa and 44.49 kJ/m2, respectively. It was found that about 29% and 17% of flexural strength and 29% and 78% of impact strength was improved for RBFC than BFC and RFC respectively. Finally, fabricated composites mechanical characteristics were compared to the Acrylonitrile Butadiene Styrene or ABS plastic materials mechanical characteristics.

Compact and modular autonomous surface vehicle for water research: The Naval Operating Research Drone Assessing Climate Change (NORDACC)

Research, monitoring, and management of marine and aquatic ecosystems often require surface water samples to measure biogeochemical and optical parameters. Traditional sampling with a boat and several personnel onboard can be labor-intensive and safety requirements limit sampling activities in high-risk environments. This paper describes the Naval Operating Research Drone Assessing Climate Change (NORDACC). NORDACC is an open source, light-weight, and portable autonomous surface vehicle that can acquire surface water samples while also measuring sea surface temperature and salinity for the duration of its deployment. NORDACC is ideal for operations in remote areas where resources and personnel are limited. Two sample bottles, each one liter in volume, can be filled, either at pre-programmed sampling stations or manually, using the remote control. A trimaran design provides buoyancy and stability, with hulls constructed of vacuum-formed acrylonitrile butadiene styrene (ABS) plastic. NORDACC can navigate autonomously between waypoints and features first person view capabilities for enhanced situational awareness. NORDACC’s performance was validated in Aarhus Bay, Denmark, collecting multiple surface water samples in winds in excess of 8 ms−1 and steep, choppy waves.

Variability in Donor Lung Culture and Relative Humidity Impact the Stability of 2009 Pandemic H1N1 Influenza Virus on Nonporous Surfaces.

Respiratory viruses can be transmitted by multiple modes, including contaminated surfaces, commonly referred to as fomites. Efficient fomite transmission requires that a virus remain infectious on a given surface material over a wide range of environmental conditions, including different relative humidities. Prior work examining the stability of influenza viruses on surfaces has relied upon virus grown in media or eggs, which does not mimic the composition of virus-containing droplets expelled from the human respiratory tract. In this study, we examined the stability of the 2009 pandemic H1N1 (H1N1pdm09) virus on a variety of nonporous surface materials at four different humidities. Importantly, we used virus grown in primary human bronchial epithelial cell (HBE) cultures from different donors to recapitulate the physiological microenvironment of expelled viruses. We observed rapid inactivation of H1N1pdm09 on copper under all experimental conditions. In contrast to copper, viruses were stable on polystyrene plastic, stainless steel, aluminum, and glass, at multiple relative humidities, but greater decay on acrylonitrile butadiene styrene (ABS) plastic was observed at short time points. However, the half-lives of viruses at 23% relative humidity were similar among noncopper surfaces and ranged from 4.5 to 5.9 h. Assessment of H1N1pdm09 longevity on nonporous surfaces revealed that virus persistence was governed more by differences among HBE culture donors than by surface material. Our findings highlight the potential role of an individual's respiratory fluid on viral persistence and could help explain heterogeneity in transmission dynamics. IMPORTANCE Seasonal epidemics and sporadic pandemics of influenza cause a large public health burden. Although influenza viruses disseminate through the environment in respiratory secretions expelled from infected individuals, they can also be transmitted by contaminated surfaces where virus-laden expulsions can be deposited. Understanding virus stability on surfaces within the indoor environment is critical to assessing influenza transmission risk. We found that influenza virus stability is affected by the host respiratory secretion in which the virus is expelled, the surface material on which the droplet lands, and the ambient relative humidity of the environment. Influenza viruses can remain infectious on many common surfaces for prolonged periods, with half-lives of 4.5 to 5.9 h. These data imply that influenza viruses are persistent in indoor environments in biologically relevant matrices. Decontamination and engineering controls should be used to mitigate influenza virus transmission.

PCM-based ceiling panels for passive cooling in buildings: A CFD modelling

To relieve the upsurge of the energy demand associated to building indoor cooling, passive cooling employing phase change materials (PCMs) has been proposed as a promising technique to stabilise indoor air temperature fluctuation and reduce building energy demand. PCMs can exchange a large amount of latent heat during the melting and solidification processes, which can be utilised in line with the discharging and charging processes of a cooling system. The use of encapsulated PCM ceiling panels in buildings has immense application potential for passive cooling, which has attracted investigations in recent years. The geometry selection of the PCM ceiling panel is vital as it determines the exposed surface area to the surrounding air and the natural convection, and therefore the heat transfer rate to/from the PCM, which generally suffers from low thermal conductivity. This paper builds on the geometric optimisation of enclosed PCM capsules driven by natural convection, aiming to investigate the phase change behaviour and thermal performance of encapsulated PCM ceiling panels of different geometries. Here, the presented study focuses on the conjugate heat transfer phenomena through the surrounding air, panel shell, and PCM. A mixture of lauric, capric, and oleic acids was selected as PCM encapsulated in a thin-shell enclosure made of acrylonitrile butadiene styrene plastic, which forms the aesthetic panels attached to the ceiling. A computational fluid dynamics model was validated using full-scale experimental data and further employed to analyse the discharging process and design considerations of the PCM ceiling panels. The effects of various influencing factors were explored, such as panel volume, the initial temperature difference between PCMs and surrounding air, shell thickness, and geometrical features. The results indicate that the panel comprised of a pyramid array is more advantageous than the tetrahedral-based panel in terms of thermal performance, where the average melting rate is 20.8 % higher when the panel volume is 250 mL. In addition, tweaking the geometric features of the panel will largely impact its thermal performance as the effective heat transfer area and natural convection conditions are varied. Finally, it was found that hanging the panel to the ceiling will effectively enhance the heat transfer compared to directly attaching it to the ceiling. The results complement the knowledge body of macro-encapsulated PCM ceiling panels in terms of thermal performance and geometric optimisation. The effects of geometric features on the thermal performance of the PCM ceiling panels are studied in a more holistic manner.

Semiautomated intraoperative measurement of Cobb angle and coronal C7 plumb line using deep learning and computer vision for scoliosis correction: a feasibility study.

Scoliosis is a degenerative disease with a 3D deformity in the alignment of the spinal column. Surgical spinal correction outcomes are heavily dependent on the surgeon's expertise and use of visual cues because of time requirements, lack of automation, and radiation exposure associated with current intraoperative measurement techniques. In this study, the authors sought to validate a novel, nonradiographic, and semiautomated device that measures spinal alignment intraoperatively using deep learning and computer vision. To obtain spinal alignment metrics intraoperatively, the surgeon placed 3D-printed markers made of acrylonitrile butadiene styrene (ABS) plastic at designated locations in the surgical field. With the high-definition camera of the device, the surgeon can take an image of the markers in the surgical field. Images are processed through a computer vision model that detects the location of the markers and calculates the Cobb angle and coronal plumb line. The marker detection model was trained on 100 images and tested on 130 images of the ABS markers in various conditions. To verify the Cobb angle calculation, 50 models of angle templates from 0° to 180° in 3.6735° increments were created for testing. To verify the plumb line calculation, 21 models of plumb line measurements from -10 to +10 cm in increments of 1 cm were created for testing. A validation study was performed on a scoliotic cadaver model, and the radiographic calculations for Cobb angle and plumb line were compared with the device's calculations. The area under the curve for the marker detection model was 0.979 for Cobb angle white, 0.791 for Cobb angle black, and 1 for the plumb line model. The average absolute difference between expected and measured Cobb angles on the verification models was 1.726° ± 1.259°, within the clinical acceptable error of 5°. The average absolute difference between the expected and measured plumb lines on the verification models was 0.415 ± 0.255 cm. For the cadaver validation study, the differences between the radiographic and device calculations for the Cobb angle and plumb line were 2.78° and 0.29 cm, respectively. The authors developed and validated a nonradiographic, semiautomated device that utilizes deep learning and computer vision to measure spinal metrics intraoperatively.

Crashworthiness design of graded cellular materials: Experimental verification of the backward design strategy

Graded cellular materials with a suitable design may improve the crashworthiness of protective structures. A backward design strategy considering the loading-rate sensitivity of cellular material has been proposed in the companion paper to guide the crashworthiness design of graded cellular material for protecting a moving object. Detailed experimental results are presented in this study to verify the feasibility and estimate the accuracy of this design strategy. A rate-dependent, rigid–plastic hardening (D-R–PH) idealization was employed to model cellular materials. A two-specimen test method was developed to determine the dynamic material parameters and their relationship with the relative density for the crashworthiness design. A power-law relationship between the dynamic material parameters and the relative density for the closed-cell foam with acrylonitrile butadiene styrene (ABS) plastic as the matrix material was obtained and employed in the crashworthiness design. Additive manufacturing was employed to fabricate the designed graded cellular specimens with ABS plastic, and the Taylor–Hopkinson pressure bar experimental technique together with high-speed photography was applied to perform impact tests. Graded ABS closed-cell foam specimens for different design conditions, e.g., the initial impact velocity, impact mass, and design target of impact force, were designed by the D-R–PH backward design strategy and prepared, and the corresponding impact tests were conducted. The impact force applied on the mass remains relatively stable and meets the crashworthiness requirement in all test cases. Therefore, the feasibility and reliability of the crashworthiness backward design strategy are verified, and this design strategy can be used to guide the crashworthiness design in engineering practice.