Artículos de revistas: "Polyurethane foam smart mattress"

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Jenkins, R. O., T.-A. Morris, P. J. Craig, W. Goessler, N. Ostah y K. M. Wills. "Evaluation of cot mattress inner foam as a potential site for microbial generation of toxic gases". Human & Experimental Toxicology 19, n.º 12 (diciembre de 2000): 693–702. http://dx.doi.org/10.1191/096032700670028460.

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Recent reports of biovolatilisation of phosphorus and antimony by anaerobic bacteria and of leaching of phosphorus and antimony fire-retardant additives from PVC cot mattress covers, indicate that the polyurethane inner-foam of cot mattresses could be a site for generation of toxic gases of group 15 elements. A toxic gas hypothesis for sudden infant death syndrome (SIDS) involving polyurethane foam of cot mattresses was proposed and tested experimentally. Levels of antimony, phosphorus, arsenic and bismuth were determined at four sites for 44 SIDS and 50 control (no death) cot mattress foams. There was no evidence to suggest that the levels of these elements in cot mattress foam have a causal relation to SIDS. Leaching of antimony trioxide from PVC mattress covers could account for detectable levels of this element in 52% of the cot mattress samples analysed. Volatile forms of antimony, phosphorus, arsenic and bismuth was not detected in the headspace of mixed or monoseptic cultures of anaerobic bacteria containing polyurethane foam. Past microbial activity had given rise to involatile methylated species of antimony in some of the cot mattress foams tested (61%, n = 24). Abiotic oxidation of biogenic trimethylatimony together with physical adsorption of methylantmony forms to the polyurethane foam matrix could account for the apparent absence of “escaped” volatile antimony species in culture headspaces of incubation vial. There was no evidence to suggest that levels of trimethylantimony or total methylantimony forms in cot mattress foams have a causal relation to SIDS.

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FUWA, YASUHIRO, WAN ZUHA WAN HASAN y HIROSHI YAMADA. "MEASUREMENT AND FINITE ELEMENT ANALYSIS OF THE LOAD-DEPENDENT PRESSURE REDISTRIBUTION BEHAVIOR OF VARIOUS TYPES OF MATTRESSES". Journal of Mechanics in Medicine and Biology 20, n.º 05 (junio de 2020): 2050031. http://dx.doi.org/10.1142/s0219519420500311.

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Load dependence must be kept in mind when evaluating mattress pressure redistribution, to prevent the development of pressure ulcers at bony prominences. However, there is no standardized method for analyzing load-dependent behavior after mattress pressure redistribution. In this study, a portable palmtop device with a simple load-sensing mechanism was developed for measuring the mean pressure exerted by a protruding shaft surrounded by a disc on low-resilience polyurethane (LRPu) foam, latex foam, coconut fiber and latex (CFL) mattresses, as well as polyurethane (Pu) foam bed and an LRPu foam mattress laid on a bed. Finite element (FE) analysis was used to analyze deformation and contact pressure in detail. The pressure redistribution was greatest for the LRPu foam mattress, and excessive compression was avoided by using an underlay made of stiff Pu foam. FE analysis revealed that the contact pressure increased significantly near the outer circumference of the protruding shaft and the surrounding disc. Significant nonuniformity in pressure was evident, according to the edge and bottom geometry of the device. The measurements and FE analysis revealed load-dependent pressure redistribution behavior, which should allow mattresses to be tailored on an individual basis.

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Vickery, Walker M., Juhi Singh, Jason D. Orlando, Ting-Chih Lin, Julia Wang y Stefanie A. Sydlik. "Polyurethane-grafted graphene oxide from repurposed foam mattress waste". RSC Advances 15, n.º 4 (2025): 2737–48. https://doi.org/10.1039/d4ra06691j.

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Vlaović, Zoran, Nino Klarić y Danijela Domljan. "Investigating the Impact of Long-Term Use on Mattress Firmness and Sleep Quality—Preliminary Results". Applied Sciences 14, n.º 21 (2 de noviembre de 2024): 10016. http://dx.doi.org/10.3390/app142110016.

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Mattress comfort, often associated with firmness, is a complex construct influenced by factors such as material composition, construction, and personal preference. In this short communication paper, we indirectly investigated the effects of long-term mattress use on its hardness and sleep quality by observing the changes in the mattress. A mechanical durability test was performed on two structurally different mattress samples (with polyurethane core and pocket spring core) using a modified method based on the EN 1957 standard, aiming to understand the long-term effects of mattress characteristics on sleep quality. Preliminary results confirm that the mattress samples can maintain firmness and support during long-term use. The polyurethane foam mattress experienced initial compression but quickly stabilized, while the pocket spring mattress showed slight softening, maintaining overall firmness. For the polyurethane mattress, after the initial drop, the hardness value stabilized, varying between 7.53 and 9.03 N/mm, and at the end of the test, it stopped at 8.60 N/mm. The firmness rating stabilized at 4.3, showing minimal fluctuation between 4.0 and 4.6 throughout the process, while the total height loss was 3.79 mm. The hardness value of pocket spring mattresses generally decreased with increasing test cycles (it started at 5.86 N/mm and ended at 5.21 N/mm). The firmness remained relatively stable, varying between 7.3 and 7.1, and the total height loss was only 2.86 mm. The findings suggest that the firmness of a mattress can be changed with its use, highlighting the need for further research on a larger number of samples in the direction of the long-term implications of these changes on sleep comfort.

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Liu, Qingqing, Yanting Gu, Wei Xu, Tao Lu, Wenjun Li y Haibin Fan. "Compressive Properties of Polyurethane Fiber Mattress Filling Material". Applied Sciences 12, n.º 12 (16 de junio de 2022): 6139. http://dx.doi.org/10.3390/app12126139.

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There is an inevitable trend toward exploring new, environmentally friendly fibers that can be used as raw material for mattresses with moderate hardness and air-permeable characteristics. Ethylene-propylene side by side (ES), high-shrinkage fibers, and thermoplastic polyester elastomer (TPEE) chips were introduced into polyethylene glycol terephthalate (PET)/polybutylene terephthalate (PBT) chip by melt blending to modify PET/PBT fiber. The modified PET/PBT (hereinafter referred to as PLON) is more suitable for mattress filling material than PET/PBT. To explore the compressive properties of PLON cushion made of PLON fiber and expand the scope of the PLON cushion’s application, a layered hardness test, hardness classification test and variance analysis were used to comprehensively evaluate the surface hardness, core hardness, bottom hardness and hardness classification of the mattress made of PLON cushion. The conclusions are: (1) The materials of the support layer have a significant effect on the hardness grade S. The hardness of the mattress with PLON as the support layer is between the spring and the coir; (2) when PLON is used as the material of the support layer, it possesses higher supporting force than coir and the characteristics of light weight and high resilience, which coir does not have; it is also softer than a spring mattress. As cushion material, it provides higher support for mattresses than foam. Practical applications, densities and structure were clarified through the above research, with implications for broader applications for PLON blocks in mattress products.

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Hillier, K., T. Schupp y I. Carney. "An Investigation into VOC Emissions from Polyurethane Flexible Foam Mattresses". Cellular Polymers 22, n.º 4 (julio de 2003): 237–59. http://dx.doi.org/10.1177/026248930302200402.

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Emissions of volatile species from flexible polyurethane foam mattresses were investigated by using large scale chamber tests designed to replicate the product use as mattress cores. Various trace impurities were identified and their concentrations were measured for input into a human health and toxicity risk assessment, which has concluded that none was injurious to health. The raw materials used to make the foam were analysed to identify the source of emanations and routes to their reduction or elimination. Several analytical artefacts were identified, and some recommendations made for their avoidance. Detailed product knowledge was essential to the reliable interpretation of analytical data. A quantitative risk assessment was carried out on each of the volatiles. No evidence of any human health risk was identified from the ‘worst-case’ exposure model employed

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Haigh, Robert. "A Review and Thermal Conductivity Experimental Program of Mattress Waste Material as Insulation in Building and Construction Systems". Construction Materials 4, n.º 2 (29 de abril de 2024): 401–24. http://dx.doi.org/10.3390/constrmater4020022.

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The building and construction industry consumes a significant amount of natural resources alongside contributing to the generation of waste materials. Addressing the dual challenge of waste management and recycling in this sector is imperative. This study begins with a bibliometric assessment to identify waste materials used as insulation in building and construction systems. The assessment of 2627 publications revealed mattress waste materials were seldom considered. The aim of this research focuses on exploring alternative methods for repurposing mattress materials in construction, aiming to mitigate waste generation. While various materials are being recycled for building applications, this research emphasises the potential of incorporating recycled polyurethane foam (PUF) from mattresses as insulation products. A transient plane source (TPS) was employed to determine the thermal conductivity of waste mattress PUF obtained from a recycling plant in Victoria, Australia. The results exhibited promising thermal resistance, with a mean value of 0.053 Wm/K. However, optimal thermal performance was observed with increased thickness, suggesting that a thickness of 215mm aligns with industry standards for building fabric systems. Further research is required to comprehensively analyse moisture resistance and fire retardation of waste mattress materials. This paper presents key findings of current trends, limitations, and future research directions to the use of waste mattress PUF as an insulation material.

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Jaiswal, Harshi, Mahesh N. Gopalasamudram y Jaya Maitra. "Improvisation in wicking property of flexible polyurethane foams by adding bamboo and gelatin fillers". Brazilian Journal of Development 10, n.º 1 (16 de enero de 2024): 1143–56. http://dx.doi.org/10.34117/bjdv10n1-075.

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PU foam is one of the softest, most easily accessible, and affordable mattress materials. In PU foam, wider pores and a more open-cell structure have both advantages and drawbacks. Despite having fewer cells PU foam does not control airflow very effectively and commonly faces criticism for causing body heat and for retaining moisture. A warm, humid climate because of stored body moisture and sweat functions as a haven for bacteria and germs and encourages the proliferation of dust mites contributing to excessive odour and allergic reactions. This study aims to investigate the impact of bamboo and gelatin filler dosage or loading on the wicking property of the foam by using a discontinuous foaming process. Foams with gelatin and bamboo fillers were prepared at 2, 4, and 8% by weight concentrations, respectively, along with a standard 32-density foam without filler. A comparative study was conducted on the effect of increasing filler content on the wicking and mechanical properties of the foam. The wicking and porosity levels of bamboo-filled foam were higher than standard foam and gelatin-loaded foam. With increasing concentrations of bamboo filler, a rapid increase in foam wicking by 7–10 mm was noted. However, an increase in gelatin filler concentration resulted in an increase in foam porosity and elongation with a slight improvement in wicking ability. Improvisation in the wicking property of the foam was observed with dosage increment of bamboo filler. According to this research findings, the bamboo powder can be utilized as a filler to enhance wicking properties in flexible polyurethane foam.

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Bai, Dorothy Li, Tsai-Wen Liu, Hsiu-Ling Chou y Yeh-Liang Hsu. "Relationship between a pressure redistributing foam mattress and pressure injuries: An observational prospective cohort study". PLOS ONE 15, n.º 11 (9 de noviembre de 2020): e0241276. http://dx.doi.org/10.1371/journal.pone.0241276.

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Background and purpose Pressure injuries remain a significant health care issue in various settings. The purpose of this study was to examine the relationship between a pressure redistributing foam mattress (PRFM) and the development of pressure injuries. Methods This study employed an observational prospective cohort study design. We enrolled 254 participants from the intensive care unit who were at risk of developing pressure injuries. Participants were exposed to either a nonpressure redistributing foam mattress (NPRFM), which was the standard mattress used at the study site, or a PRFM made of viscoelastic, temperature-sensitive, polyurethane memory foam. The patients’ assignment to either a PRFM or NPRFM was performed upon their admission, before the study eligibility screening. The relationship between the PRFM and the development of pressure injuries was studied using a logistic regression model. Results The overall incidence of pressure injuries was 5.9% (15/254) in our study, with 1.6% (2/127) for participants who used a PRFM and 10.2% (13/127) for those using a NPRFM. After adjusting for potential confounding variables, use of a PRFM was associated with an 88% reduced risk of pressure injury development (OR = 0.12, 95% CI: 0.03, 0.56, P = 0.007). The use of a PRFM also contributed to a postponed occurrence of pressure injuries by 4.2 days on average in comparison with that of a NPRFM (P = 0.041). Conclusions A PRFM is associated with a significantly reduced incidence and postponed occurrence of pressure injuries. It is recommended to use a PRFM for patients at risk of developing pressure injuries.

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Brady, Sarah, Dermot Diamond y King-Tong Lau. "Inherently conducting polymer modified polyurethane smart foam for pressure sensing". Sensors and Actuators A: Physical 119, n.º 2 (abril de 2005): 398–404. http://dx.doi.org/10.1016/j.sna.2004.10.020.

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Gong, Qichun, Jinkui Wu, Xinglong Gong, Yanceng Fan y Hesheng Xia. "Smart polyurethane foam with magnetic field controlled modulus and anisotropic compression property". RSC Advances 3, n.º 10 (2013): 3241. http://dx.doi.org/10.1039/c2ra22824f.

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Cámara-Hinojosa, Alma, Darío Bueno-Baqués, Oliverio S. Rodríguez-Fernández y Ronald F. Ziolo. "Synthesis and Characterization of Magnetic Polyurethane Nanocomposite Foams". Materials Science Forum 644 (marzo de 2010): 29–32. http://dx.doi.org/10.4028/www.scientific.net/msf.644.29.

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New magnetic polyurethane nanocomposite foams have been synthesized by the one-shot method. The opened-cell soft foams contain a dispersion of uniformly sized nanocrystalline iron oxide prepared ex situ by the high temperature thermal decomposition of iron acetylacetonate in phenyl ether in the presence of oleic acid. The magnetic particles were dispersed in polyol by sonication prior to the reaction of the latter with isocyanate to produce the magnetic foams. A 7 wt% loading of iron oxide yielded a soft, flexible foam with a room temperature magnetization of 3.5 emu/g at one Tesla. Higher loadings of iron oxide are possible without destruction of the soft open-cell polyurethane structure. Physicochemical characterization of the foams will be presented along with magnetic and mechanical properties. Potential applications include smart materials such as magnetic shape memory foams, adhesive-free metal to foam seals, inductively coupled thermal foams and applications for conformable foams having a magnetic component such as healthcare products.

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Yang, Ping’an, Sha Xiang, Rui Li, Haibo Ruan, Dachao Chen, Zhihao Zhou, Xin Huang y Zhongbang Liu. "Highly Stretchable and Sensitive Flexible Strain Sensor Based on Fe NWs/Graphene/PEDOT:PSS with a Porous Structure". International Journal of Molecular Sciences 23, n.º 16 (10 de agosto de 2022): 8895. http://dx.doi.org/10.3390/ijms23168895.

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With the rapid development of wearable smart electronic products, high-performance wearable flexible strain sensors are urgently needed. In this paper, a flexible strain sensor device with Fe NWs/Graphene/PEDOT:PSS material added under a porous structure was designed and prepared. The effects of adding different sensing materials and a different number of dips with PEDOT:PSS on the device performance were investigated. The experiments show that the flexible strain sensor obtained by using Fe NWs, graphene, and PEDOT:PSS composite is dipped in polyurethane foam once and vacuum dried in turn with a local linearity of 98.8%, and the device was stable up to 3500 times at 80% strain. The high linearity and good stability are based on the three-dimensional network structure of polyurethane foam, combined with the excellent electrical conductivity of Fe NWs, the bridging and passivation effects of graphene, and the stabilization effect of PEDOT:PSS, which force the graphene-coated Fe NWs to adhere to the porous skeleton under the action of PEDOT:PSS to form a stable three-dimensional conductive network. Flexible strain sensor devices can be applied to smart robots and other fields and show broad application prospects in intelligent wearable devices.

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Zhong, Ding, Li, Shen, Yadav, Chen, Bao, Jiang y Wang. "Facile Fabrication of Conductive Graphene/Polyurethane Foam Composite and Its Application on Flexible Piezo-Resistive Sensors". Polymers 11, n.º 8 (1 de agosto de 2019): 1289. http://dx.doi.org/10.3390/polym11081289.

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Flexible pressure sensors have attracted tremendous research interests due to their wide applications in wearable electronics and smart robots. The easy-to-obtain fabrication and stable signal output are meaningful for the practical application of flexible pressure sensors. The graphene/polyurethane foam composites are prepared to develop a convenient method for piezo-resistive devices with simple structure and outstanding sensing performance. Graphene oxide was prepared through the modified Hummers method. Polyurethane foam was kept to soak in the obtained graphene oxide aqueous solution and then dried. After that, reduced graphene oxide/polyurethane composite foam has been fabricated under air phase reduction by hydrazine hydrate vapor. The chemical components and micro morphologies of the prepared samples have been observed by using FT-IR and scanning electron microscopy (SEM). The results predicted that the graphene is tightly adhered to the bare surface of the pores. The pressure sensing performance has been also evaluated by measuring the sensitivity, durability, and response time. The results indicate that the value of sensitivity under the range of 0–6 kPa and 6–25 kPa are 0.17 kPa−1 and 0.005 kPa−1, respectively. Cycling stability test has been performed 30 times under three varying pressures. The signal output just exhibits slight fluctuations, which represents the good cycling stability of the pressure sensor. At the same stage, the response time of loading and unloading of 20 g weight turned out to be about 300 ms. These consequences showed the superiority of graphene/polyurethane composite foam while applied in piezo-resistive devices including wide sensitive pressure range, high sensitivity, outstanding durability, and fast response.

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Poirot, Antoine, Nacera Bedrici, Jean-Christophe Walrick y Michel Arrigoni. "Piezoresistive Behavior of a Conductive Polyurethane Based-Foam for Real-Time Structural Monitoring". Sensors 23, n.º 11 (29 de mayo de 2023): 5161. http://dx.doi.org/10.3390/s23115161.

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Smart flexible materials with piezoresistive property are increasingly used in the field of sensors. When embedded in structures, they would allow for in situ structural health monitoring and damage assessment of impact loading, such as crash, bird strikes and ballistic impacts; however, this could not be achieved without a deep characterization of the relation between piezoresistivity and mechanical behavior. The aim of this paper is to study the potential use of the piezoresistivity effect of a conductive foam made of a flexible polyurethane matrix filled with activated carbon for integrated structural health monitoring (SHM) and low-energy impact detection. To do so, polyurethane foam filled with activated carbon, namely PUF-AC, is tested under quasi-static compressions and under a dynamic mechanical analyzer (DMA) with in situ measurements of its electrical resistance. A new relation is proposed for describing the evolution of the resistivity versus strain rate showing that a link exists between electrical sensitivity and viscoelasticity. In addition, a first demonstrative experiment of feasibility of an SHM application using piezoresistive foam embedded in a composite sandwich structure is realized by a low-energy impact (2 J) test.

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Park, Yu-Jin, Ji-Young Yoon, Byung-Hyuk Kang, Gi-Woo Kim y Seung-Bok Choi. "A Tactile Device Generating Repulsive Forces of Various Human Tissues Fabricated from Magnetic-Responsive Fluid in Porous Polyurethane". Materials 13, n.º 5 (27 de febrero de 2020): 1062. http://dx.doi.org/10.3390/ma13051062.

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In this study, a controllable tactile device capable of realizing repulsive forces from soft human tissues was proposed, and its effectiveness was verified through experimental tests. The device was fabricated using both porous polyurethane foam (PPF) and smart magnetorheological fluid (MRF). As a first step, the microstructural behavior of MRF particle chains that depended on the magnetic field was examined via scanning electron microscopy (SEM). The test samples were then fabricated after analyzing the magnetic field distribution, which was crucial for the formation of the particle chains under the squeeze mode operation. In the fabrication of the samples, MRF was immersed into the porous polyurethane foam and encapsulated by adhesive tape to avoid leakage. To verify the effectiveness of the proposed tactile device for appropriate stiffness of soft human tissues such as liver, the repulsive force and relaxation stress were measured and discussed as a function of the magnetic field intensity. In addition, the effectiveness and practical applicability of the proposed tactile device have been validated through the psychophysical test.

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YAMADA, Hiroshi y Yasuhiro FUWA. "Effect of the geometry of the device with a cylindrical protrusion on the measurement of pressure redistribution of polyurethane foam mattress". Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2018.30 (2018): 2D19. http://dx.doi.org/10.1299/jsmebio.2018.30.2d19.

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de Boer, R. "Effect of heat treatments on the house-dust mitesDermatophagoides pteronyssinus andD. farinae (Acari: Pyroglyphidae) in a mattress-like polyurethane foam block". Experimental & Applied Acarology 9, n.º 1-2 (agosto de 1990): 131–36. http://dx.doi.org/10.1007/bf01198991.

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Rodrigues da Silva, Manoel, João Antonio Pessoa da Silva, Cesar Liberato Petzhold, Nilo Sérgio Medeiros Cardozo y Mariliz Gutterres. "Preparation of Polyols and Polyurethane Foams from Olein By-Product of Tanning Industry". Journal of the American Leather Chemists Association 117, n.º 11 (1 de noviembre de 2022): 489–97. http://dx.doi.org/10.34314/jalca.v117i11.6295.

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Olein produced from the solid residues of the tanning industry is already employed as raw material to obtain greasing oil for leather. However, new applications for this product may be advantageous regarding environmental impact and sustainability of this industry. In this work, flexible polyurethane foams (FPUFs) were prepared from polyols obtained from olein. A polyol from olein was prepared through alkaline glycerolysis. The glycerolysis conditions of temperature, glycerol/olein molar ratio, amount of catalyst and reaction time were optimized using a 24 factorial design, resulting in an olein polyol containing around 75% of monoacylglycerols, hydroxyl value (388.68±0.40 mg KOH.g-1), and hydroxyl functionality of 2.89. FPUFs were prepared at NCO/OH ratios of 1.2:1 and 1.3:1, using an aliphatic hexamethylene diisocyanate trimer and water as foaming agent. The foams were characterized through FTIR, thermogravimetry, morphology, extractable materials, and mechanical properties. Characteristics urethane/urea groups formation were verified by FTIR as well as typical mass loss steps in the thermal decomposition curves. The foams morphology showed a structure composed mainly for polygon-type closed-cells. The obtained FPUFs presented a content of extractable materials lower than 3%. The mechanical properties of the foams were dependent on the NCO/OH ratio, and the foam prepared at the ratio of 1.2:1 stood out as a potential material to be used in the production of mattresses. This study demonstrated the feasibility of transforming olein, a solid residue of the tanning industry, as a precursor to prepare PU foams, which may be a promising material for mattress applications, considering the observed features.

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Brusamarello, Beatriz, Uilian José Dreyer, Gilson Antonio Brunetto, Luis Fernando Pedrozo Melegari, Cicero Martelli y Jean Carlos Cardozo da Silva. "Multilayer Structure Damage Detection Using Optical Fiber Acoustic Sensing and Machine Learning". Sensors 24, n.º 17 (5 de septiembre de 2024): 5777. http://dx.doi.org/10.3390/s24175777.

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Over the past decade, distributed acoustic sensing has been utilized for structural health monitoring in various applications, owing to its continuous measurement capability in both time and space and its ability to deliver extensive data on the conditions of large structures using just a single optical cable. This work aims to evaluate the performance of distributed acoustic sensing for monitoring a multilayer structure on a laboratory scale. The proposed structure comprises four layers: a medium-density fiberboard and three rigid polyurethane foam slabs. Three different damages were emulated in the structure: two in the first layer of rigid polyurethane foam and another in the medium-density fiberboard layer. The results include the detection of the mechanical wave, comparing the response with point sensors used for reference, and evaluating how the measured signal behaves in time and frequency in the face of different damages in the multilayer structure. The tests demonstrate that evaluating signals in both time and frequency domains presents different characteristics for each condition analyzed. The supervised support vector machine classifier was used to automate the classification of these damages, achieving an accuracy of 93%. The combination of distributed acoustic sensing with this learning algorithm creates the condition for developing a smart tool for monitoring multilayer structures.

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Park, Yu-Jin, Ji-Young Yoon, Ye-Ho Lee y Seung-Bok Choi. "The Repulsive Force Spectrum of Magnetorheological Fluids Based Tactile Devices Applicable to Robot Surgery". Current Smart Materials 4, n.º 1 (2 de julio de 2019): 75–82. http://dx.doi.org/10.2174/2405465804666190408153521.

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Objective: This paper presents controllable force ranges of tactile devices made of smart Magnetorheological Fluids (MRF) and porous sponges (MR sponges in short). Methods: In order to identify the wide controllable range of the field-dependent repulsive force, three MR sponge samples with three different MR fluids are fabricated using polyurethane foam and cling film. Then, the repulsive forces of the samples are measured using the motor-driven experimental apparatus and the results are presented with minimum and maximum values of the repulsive forces. On the other hand, in order to investigate the feasibility of the proposed tactile device for application to Robot-assisted Minimally Invasive Surgery (RMIS), pig’s organs such as liver, lung and heart, whose viscoelastic properties are very similar to those of human tissues, are tested under same conditions. Results: It is shown that the range of the repulsive spectrum of the pig’s organs can be achieved using the proposed samples by controlling the magnetic field intensity to be applied to MRF domain.

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Bhullar, Sukhwinder K. "Three decades of auxetic polymers: a review". e-Polymers 15, n.º 4 (1 de julio de 2015): 205–15. http://dx.doi.org/10.1515/epoly-2014-0193.

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AbstractDevelopments in design and technology in the engineering and medical fields necessitate the use of smart and high-performance materials to meet higher engineering specifications. The general requirements of such materials include a combination of high stiffness and strength with significant weight savings, resistance to corrosion, chemical resistance, low maintenance, and reduced costs. Over the last three decades, it has been demonstrated that auxetic materials offer a huge potential for the fields of engineering, natural sciences, and biomedical engineering, and for many other industries, including the aerospace and defense industries, through their unique deformation mechanism and measured enhancements in mechanical properties. To meet future engineering challenges, auxetic materials are increasingly being recognized as integral components of smart and advanced materials. Although materials with a negative Poisson’s ratio have been known since the early 1900s, they did not capture researchers’ attention until the late 1980s. Since 1991, these materials have been known as auxetic materials. Since then, their benefits and applications have been expanded to all major classes of materials such as metals, ceramics, polymers, and composites, and they are also now being used in engineering applications. The goal of this review was to present the development of auxetic polymers, which were first fabricated in the form of polyurethane foam approximately three decades ago and are now used in the fabrication of non-woven nano/micropolymeric structures. This review could provide useful information for the future development of auxetic polymers.

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"Development of shoe insert for Diabetic Foot Ulcer Patients in case of Ethiopia". Stem Cell Research International 4, n.º 2 (24 de diciembre de 2021). http://dx.doi.org/10.33140/scri.04.02.05.

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Foot ulcer is mainly developing due to diabetic disease. It is an open sore on the foot. The aim of this research is to develop polyurethane memory foam in sock/shoe insert in Ethiopia by replacing costly material silicon surfactant by locally available and affordable input materials castor oil as surfactant and tap water instead of distilled water for the diabetic foot ulcer patients. Under this research, it was able to prove the severity of foot ulcer in Ethiopia and enhance the high demand of orthotic appliance. Three memory foams in sock with different surfactant ratios were manufacture at AMAGA P.L.C foam factory, Bahir Dar Ethiopia using standard Polyols and diisocynates. The shoe insert /in sock was prepared by using materials used in the factory to prepare polyurethane (PU) memory foam mattress with 5g, 9.5 g and 10.36g of castor oil surfactant amount as a new replaced material instead of costly silicon surfactant from the three the first (castor oil 5g is not form a foam and hence no further investigation is conducted on it). Physical properties such as thickness, density, hardness, compression set, water absorption and abrasion resistance of developed in sock were tested. Further the new developed in sock was compared with that of existed commercial polyurethane in sock and the SATRA standards. The new developed in sock has showed an equivalent mechanical property with the standard.

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Jaiswal, Harshi, Mahesh Narayanangopalasamudram y Jaya Maitra. "Impact of filler and gelling catalyst/agent on properties of flexible polyurethane foam". Polymer Engineering & Science, 14 de febrero de 2024. http://dx.doi.org/10.1002/pen.26646.

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AbstractIn this study, the physiomechanical properties of carboxymethylcellulose sodium salt (Na‐CMC salt) filler‐loaded foam and its impact on the wicking capacity of the foam were investigated in juxtaposition with the increasing tin concentration. According to the study's findings, standard unfilled foam demonstrated no wicking at all, while flexible PU foam filled with Na‐CMC salt, even with low porosity and subpar mechanical traits, displayed wicking heights of 4 mm, 3.4 mm, and 2.8 mm in test specimens of thicknesses of 6 mm, 8 mm, and 10 mm. Moreover, filled foam with a higher porosity level exhibited significantly better wicking heights of 11.4 mm, 10.8 mm, and 8.2 mm. The inclusion of CMC filler in the PU foam matrix is the reason for enhanced wicking property in foam. The sample thickness and wicking height trends are consistent among all foams; as foam sample thickness increases, wicking height progressively falls. The correlation between the foam's porosity value and the number of closed cell windows is confirmed by stereomicroscopy and the porosity values. According to this study, the infused filler's characteristics have a greater influence on the foam's wicking capacity than the foam's porosity. This study contributes significant insights into ongoing initiatives to enhance user experience, well‐being, and hygiene through innovative and meticulously designed new developed mattress foam using Na‐CMC as a filler.Highlights Co‐relation between concentration of tin and infused filler on wicking property. Standard unfilled foam demonstrated no wicking at all. Na‐CMC salt filled foam displayed wicking heights. After 15% increase in tin level, mechanical properties of foam degrade. Wicking depends on nature of infused filler and the foam's porosity.

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Yao, Yongtao, Yuncheng Xu, Hao Chen, Yuying Kang, Yanju Liu y Jinsong Leng. "Fabrication and characterization of shape memory auxetic metamaterial". Journal of Intelligent Material Systems and Structures, 23 de mayo de 2022, 1045389X2210994. http://dx.doi.org/10.1177/1045389x221099452.

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The process of repeating shape memory cycle of the shape memory foam whose initial structure is nonauxetic is more complex. In this cases, only one-shot deformation, which will greatly limit the application of this smart metamaterial. Thus, in this study, we report a feasible approach of fabricating the original structure of shape memory foams with auxetic property based on second curing method. The commercial soft polyurethane foam material and shape memory epoxy resin was used in fabricating the shape memory auxetic foam. Polyurethane component plays role in the similar function of “auxetic mold,” while shape memory polymer act as fixing auxetic structure of foam. The negative Poisson’s ratio was achieved around −0.22. Tunable foam mechanical property was demonstrated by structural control according to its shape memory property. The functional filler was employed to realize the wireless actuation of auxetic foam. The excellent shape memory properties have been achieved as well. The combination of smart materials and metamaterial structure makes it have excellent structural mechanical properties and intelligent properties of materials, which greatly expands their potential application prospects.

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26

de Kort, Patrick, Elke Jensen, Mark W. Spence y Patrick M. Plehiers. "Risk assessment—based verification of the CertiPUR^TM limit values for toluene diamine and methylene dianiline in flexible polyurethane foam". Toxicology and Industrial Health, 2 de enero de 2024. http://dx.doi.org/10.1177/07482337231224514.

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Flexible polyurethane foams (PUF) are used in many consumer products. PUF may contain trace levels of aromatic diamine impurities that could represent a potential health risk. The risk associated with sleeping on a PUF mattress was evaluated. Toxicity benchmarks for sensitization and non-cancer endpoints were derived from the respective points-of-departure using standard assessment factors. For the cancer endpoints, toxicity benchmarks were derived from the 25th-percentile values of animal studies. Recently published emission and migration data allowed to link exposure with the CertiPURTM voluntary quality limits of ≤5 mg.kg−1 for 2,4-toluene diamine and 4,4’-methylene dianiline in PUF. Using conservative exposure scenarios, lifetime-average daily internal doses from the combined inhalation and dermal exposures were calculated. Margins of safety for non-cancer and sensitization endpoints were >104. The theoretical excess cancer risk was ≤1.5 × 10−7. It is concluded that sleeping on a mattress that satisfies the CertiPUR limit value does not pose undue risk to consumers.

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27

Yu, Mi, Kyung Hee Park, Jiseon Shin y Ji Hyun Lee. "Predicting the cut‐off point for interface pressure in pressure injury according to the standard hospital mattress and polyurethane foam mattress as support surfaces". International Wound Journal, 2 de febrero de 2022. http://dx.doi.org/10.1111/iwj.13750.

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28

Rizzi, Francesco, Salvatore Puce, Francesco La Malfa, Massimo Totaro, Massimo De Vittorio y Lucia Beccai. "MODELING AND DEVELOPMENT OF AN AUXETIC FOAM-BASED MULTIMODAL CAPACITIVE STRAIN GAUGE". Smart Materials and Structures, 3 de enero de 2023. http://dx.doi.org/10.1088/1361-665x/acafb7.

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Abstract Auxetics are mechanical metamaterials with the unique properties of expanding their transversal section upon longitudinal positive strain, decoupling the deformations in normal and transversal directions. Such property can be exploited to develop soft sensors that can provide feedback to different mechanical stimuli, e.g. pressure and shear force. In this work, we propose for the first time a mathematical model to analytically simulate and design the auxetic behavior in a capacitive strain gauge, and show that, for a Polyurethane (PU) auxetic foam, Poisson Ratio’s values can satisfy the negative gauge factor condition. We develop an innovative thermo-compressive process to obtain anisotropic auxetic polyurethane sponges both in normal and normal/radial directions, and their mechanical properties are in agreement with the theoretical calculations validating our model. Then, we develop a capacitive strain gauge by integrating a normal auxetic PU foam with PDMS/CNTs electrodes. Results show that the capacitive change caused by an external force, is proportional to the induced deformation, but importantly it is also dependent on the direction of the applied force. A negative gauge factor of GF = -2.8 is obtained for a longitudinal strain range up to 10%. This auxetic foam structure guarantees flexibility and paves the way for an improved design freedom for multimodal mechanical soft sensors providing new opportunities towards smart wearables and perceptive soft robots.

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29

Cetin, Oyku, Melih Ogeday Cicek, Murathan Cugunlular, Tufan Bolukbasi, Yaqoob Khan y Husnu Emrah Unalan. "MXene‐Deposited Melamine Foam‐Based Iontronic Pressure Sensors for Wearable Electronics and Smart Numpads". Small, 29 de julio de 2024. http://dx.doi.org/10.1002/smll.202403202.

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AbstractIontronic pressure sensors hold significant potential to emerge as vital components in the field of flexible and wearable electronics, addressing a variety of applications spanning wearable technology, health monitoring systems, and human‐machine interactions. This study introduces a novel iontronic pressure sensor structure based on a seamlessly deposited Ti3C2Tx MXene layer onto highly porous melamine foam as parallel plate electrodes and an ionically conductive electrolyte of 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide/thermoplastic polyurethane coupled with carbon cloth as current collecting layers for improved sensitivity and high mechanical stability of more than 7000 cycles. MXene‐deposited melamine foam‐based iontronic pressure sensors (MIPS) showed a high sensitivity of 5.067 kPa−1 in the range of 45–60 kPa and a fast response/recovery time of 28/18 ms, respectively. The high sensitivity, high mechanical stability, and fast response/recovery time of the designed sensor make them highly promising candidates for real‐time body motion monitoring. Moreover, sensors are employed as a smart numpad for integration into advanced ATM security systems utilizing machine learning algorithms. This research marks a significant advance in iontronic pressure sensor technology, offering promising avenues for application in wearable electronics and security systems.

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30

Huang, An, Shengguo Gu, Zhenyu Yang, Xin Chen, Minghui He y Xiangfang Peng. "Flexible, Lightweight, and Hydrophobic TPU/CNT Nanocomposite Foam With Different Surface Microstructures for High‐Performance Wearable Piezoresistive Sensors". Journal of Polymer Science, 2 de diciembre de 2024. https://doi.org/10.1002/pol.20240704.

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ABSTRACTFlexible piezoresistive pressure sensors, due to their lightweight, bendable, and highly sensitive characteristics, have been widely used in fields such as wearable devices, electronic skin, and intelligent robotics. Besides the development of various high‐performance materials, the performance of these sensors is closely related to the design of their surface microstructures. Different surface microstructures can significantly enhance the sensitivity, stability, and durability of piezoresistive sensors. In this paper, three types of flexible thermoplastic polyurethane (TPU)/carbon nanotube (CNT) nanocomposite foam piezoresistive sensors with different surface microstructures and internal porous structures were prepared using supercritical carbon dioxide (sc‐CO₂) foaming process. The effects of the three surface microstructures on the piezoresistive sensing performance of TPU/CNT nanocomposite foams were studied in detail. The results show that the foam sensor with a double‐ridge surface microstructure exhibits significantly enhanced sensing performance, including high sensitivity (0.309 kPa−1), fast response time (~40 ms), wide working range (0–80 kPa), and stability over more than 600 cycles. Additionally, the prepared flexible piezoresistive sensors can be integrated into smartwatches, fitness bands, and smart clothing, enabling real‐time monitoring of heart rate, blood pressure, respiratory rate, and physical activity. This provides precise data support, demonstrating the promising application prospects of these flexible surface microstructure foam piezoresistive sensors in the future.

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31

Xing, Yanghui, Linhui Qiu, Danqing Liu, Sihan Dai y Chia-Lin Sheu. "The role of smart polymeric biomaterials in bone regeneration: a review". Frontiers in Bioengineering and Biotechnology 11 (17 de agosto de 2023). http://dx.doi.org/10.3389/fbioe.2023.1240861.

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Addressing critical bone defects necessitates innovative solutions beyond traditional methods, which are constrained by issues such as immune rejection and donor scarcity. Smart polymeric biomaterials that respond to external stimuli have emerged as a promising alternative, fostering endogenous bone regeneration. Light-responsive polymers, employed in 3D-printed scaffolds and photothermal therapies, enhance antibacterial efficiency and bone repair. Thermo-responsive biomaterials show promise in controlled bioactive agent release, stimulating osteocyte differentiation and bone regeneration. Further, the integration of conductive elements into polymers improves electrical signal transmission, influencing cellular behavior positively. Innovations include advanced 3D-printed poly (l-lactic acid) scaffolds, polyurethane foam scaffolds promoting cell differentiation, and responsive polymeric biomaterials for osteogenic and antibacterial drug delivery. Other developments focus on enzyme-responsive and redox-responsive polymers, which offer potential for bone regeneration and combat infection. Biomaterials responsive to mechanical, magnetic, and acoustic stimuli also show potential in bone regeneration, including mechanically-responsive polymers, magnetic-responsive biomaterials with superparamagnetic iron oxide nanoparticles, and acoustic-responsive biomaterials. In conclusion, smart biopolymers are reshaping scaffold design and bone regeneration strategies. However, understanding their advantages and limitations is vital, indicating the need for continued exploratory research.

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32

Selvaraj, Vinoth Kumar y Jeyanthi Subramanian. "A comparative study of smart polyurethane foam using RSM and COMSOL multiphysics for acoustical applications: from materials to component". Journal of Porous Materials, 12 de octubre de 2022. http://dx.doi.org/10.1007/s10934-022-01362-7.

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33

Güçlü, Harun, Serhat Osmanoğlu, Aslıhan Hayırkuş, Oğuzhan Taş y Murat Yazıcı. "An easy-to-implement self-healing smart design for increasing impact strength and crashworthiness resistance of honeycomb sandwich structures". Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 13 de septiembre de 2022, 146442072211254. http://dx.doi.org/10.1177/14644207221125414.

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In this paper, the dynamic compression impact response of an aluminum honeycomb core filled with open-cell foams impregnated with self-healing liquid agents was investigated experimentally. Samples were subjected to a variety of impacts in order to determine healing time and self-healing performance. Three different sandwich specimens were developed to evaluate the effectiveness of self-healing. The sandwich specimens are designated as B (empty honeycomb core cells), S (only open-cell soft polyurethane foam-filled honeycomb core cells), and self-healing agent (SHA) (open-cell soft polyurethane foams impregnated with liquid self-healing agents). The test results were presented by considering the crashworthiness and healing efficiency criteria, and the impact characteristics of the samples were compared related to these criteria. After testing, the results demonstrated that the self-healing agent specimens had much fewer buckling deformation and displacement than their counterparts. Significant improvements were achieved in healing efficiencies and crashworthiness evaluation criteria. The peak load and the energy needed to attain peak load are considered healing efficiency criteria. Self-healing agent specimens reached 29.7% and 12.9% more peak loads, and in the energy absorbed up to peak loads 140% and 34.9% higher values than the B and S sandwiches. In the same samples, crushing strain features were acquired as 50% versus 66%, indicating less displacement in self-healing agent specimens than counterparts. The results indicated that an aluminum honeycomb sandwich structure that can heal itself after damage and recover impact characteristics remarkably could be produced practically.

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34

Mahajan, U. R., I. Emmanuel, A. Sreenivasarao y S. T. Mhaske. "Development of smart polyurethane foam with combined capabilities of thermal insulation and thermal energy storage by integrating microencapsulated phase change material". Polymer Bulletin, 27 de enero de 2023. http://dx.doi.org/10.1007/s00289-023-04695-8.

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35

"Envelop Insulation for Energy Efficient Smart Buildings in India". International Journal of Innovative Technology and Exploring Engineering 8, n.º 11S (11 de octubre de 2019): 429–34. http://dx.doi.org/10.35940/ijitee.k1074.09811s19.

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The building sector is amongst the largest energy consuming sector across the world. Within the building sector, about 75 percent of the total energy is consumed by the residential buildings. The energy sector is directly and indirectly associated with greenhouse gas emissions, since majority of energy sector is dependent on fossil fuels, which are primary source of emanation. Building energy requirements are comprised of need for lighting, air conditioning and other home appliances operations. Air conditioning requirement is derived from the climatic condition in which a building exists. The building components such as walls, roof and windows are exposed to solar radiation and outside air temperature. Heat is conducted from exterior environment into the interior of the building envelop through these channels, wherein majority (approx. 60%) is conducted by walls and roof. Envelop insulation is considered as an efficient retrofitting measure to reduce heat gain from walls and roof, thereby need of air conditioning to remove that heat. In this work, envelop insulation has been designed for the Indian residential buildings existing in the three climate zones of India, i.e. warm-humid, hot-dry and composite climate zones. Electricity saving potential in an insulated envelop and associated life cycle cost saving analysis is carried out considering the application of four commercial insulation materials namely, expanded polystyrene, fiberglass, polyurethane foam and extruded polystyrene. It was concluded that at the design temperature 25˚C, annual electricity saving potential in retrofitted wall per unit area varies from 9 kWh to 16 kWh, whereas in case of roof it varies from 18 kWh to 28 kWh per unit area per year. Fiberglass is observed as the most cost effective insulation material, considering life cycle performance of the insulation material for all the climate zones.

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36

N, Rudresha, Vijay Kumar M y Mahantesh M. Math. "A parametric study and performance investigation of thermoelectric refrigeration system using computational fluid dynamics". International Journal of Air-Conditioning and Refrigeration 31, n.º 1 (31 de mayo de 2023). http://dx.doi.org/10.1007/s44189-023-00031-x.

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AbstractGlobal commercial market forecasted around 45 billion US dollars for refrigeration equipment in 2021. Currently used refrigerants have high global warming potential (GWP); hence, environment-friendly refrigeration system using the Peltier effect is being considered for this research. The thermodynamic refrigeration system has a low coefficient of performance (COP), when compared to chlorofluorocarbon (CFC) and hydrofluorocarbon (HCFC) refrigeration systems. The design of various models of the thermoelectric refrigerator (TER) is created using ANSYS workbench. Each new design is analysed with computational fluid dynamics (CFD) analysis tool by altering insulating materials such as nickel with aluminium foil and polyurethane foam in airflow streamline of thermoelectric refrigeration. Temperature differences obtained between 7.5 and 9.4 °C are tabulated after each run using the finite volume method. Optimization of inner design and insulation material is done by using computational fluid dynamics analysis in the ANSYS FLUENT software. The results of sharp edge design have proved better when compared to partially round edge design and fillet design, 7.85 °C for the cold region and 54.85 °C for the hot region. Further research is expected using the multistage Peltier module and smart temperature control unit to improve the COP of the TER system.

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