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Skrifvars, Mikael
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Publications (10 of 249) Show all publications
Kalantar Mehrjerdi, A., Skrifvars, M. & Åkesson, D. (2020). Influence of talc fillers on bimodal polyethylene composites for ground heat exchangers. Journal of applied polymer science
Open this publication in new window or tab >>Influence of talc fillers on bimodal polyethylene composites for ground heat exchangers
2020 (English)In: Journal of applied polymer scienceArticle in journal (Refereed) Published
National Category
Engineering and Technology
Identifiers
urn:nbn:se:hb:diva-23136 (URN)10.1002/app.49290 (DOI)
Available from: 2020-04-04 Created: 2020-04-04 Last updated: 2020-04-15Bibliographically approved
Kalantar Mehrjerdi, A., Bashir, T. & Skrifvars, M. (2020). Melt rheology and extrudate swell properties of talc filled polyethylene compounds. Heliyon
Open this publication in new window or tab >>Melt rheology and extrudate swell properties of talc filled polyethylene compounds
2020 (English)In: Heliyon, ISSN 2405-8440Article in journal (Refereed) Published
Abstract [en]

An experimental study of high-density polyethylene (HDPE) composites filled with talc (0–15 wt.%) was carried out to investigate the rheological properties. The apparent melt viscosity, melt density, and die-swell ratio (B) of the composites were measured at constant shear stress and constant shear rate by using a melt flow indexer and capillary rheometer. The experimental conditions were set to a temperature range from 190 to 220 C for both apparatuses whereas a load range from 5 to 12.16 kg was selected for melt flow indexer and shear rate range from 1 to 10000 s1 for capillary rheometer. The initial study showed that the talc particulates did not influence the melt viscosity compared with the neat HDPE but decreased the elasticity of the polymer system. The HDPE/talc systems obeyed power-law model in shear stress–shear rate variations and were shear thinning, meanwhile, the die-swell increased with an increased wall shear rate and shear stress. The melt density of the composites increased linearly with an increase of the filler weight fraction and decreased with the increase of the testing temperature. The talc-HDPE composites showed compressible in the molten state.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Materials science, High-density polyethylene, Talc Melt viscosity, Melt density, Die swell
National Category
Engineering and Technology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-23237 (URN)10.1016/j.heliyon.2020.e04060 (DOI)
Available from: 2020-05-27 Created: 2020-05-27 Last updated: 2020-06-01Bibliographically approved
Guo, L., Sandsjö, L., Ortiz-Catalan, M. & Skrifvars, M. (2020). Systematic review of textile-based electrodes for long-term and continuous surface electromyography recording. Textile research journal, 90(2), 227-244, Article ID 0040517519858768.
Open this publication in new window or tab >>Systematic review of textile-based electrodes for long-term and continuous surface electromyography recording
2020 (English)In: Textile research journal, ISSN 0040-5175, E-ISSN 1746-7748, Vol. 90, no 2, p. 227-244, article id 0040517519858768Article in journal (Refereed) Published
Abstract [en]

This systematic review concerns the use of smart textiles enabled applications based on myoelectric activity. Electromyography (EMG) is the technique for recording and evaluating electric signals related to muscle activity (myoelectric). EMG is a well-established technique that provides a wealth of information for clinical diagnosis, monitoring, and treatment. Introducing sensor systems that allow for ubiquitous monitoring of health conditions using textile integrated solutions not only opens possibilities for ambulatory, long-term, and continuous health monitoring outside the hospital, but also for autonomous self-administration. Textile-based electrodes have demonstrated potential as a fully operational alternative to ‘standard’ Ag/AgCl electrodes for recording surface electromyography (sEMG) signals. As a substitute for Ag/AgCl electrodes fastened to the skin by taping or pre-gluing adhesive, textile-based electrodes have the advantages of being soft, flexible, and air permeable; thus, they have advantages in medicine and health monitoring, especially when selfadministration, real-time, and long-term monitoring is required. Such advances have been achieved through various smart textile techniques; for instance, adding functions in textiles, including fibers, yarns, and fabrics, and various methods for incorporating functionality into textiles, such as knitting, weaving, embroidery, and coating. In this work, we reviewed articles from a textile perspective to provide an overview of sEMG applications enabled by smart textile strategies. The overview is based on a literature evaluation of 41 articles published in both peer-reviewed journals and conference proceedings focusing on electrode materials, fabrication methods, construction, and sEMG applications. We introduce four textile integration levels to further describe the various textile electrode sEMG applications reported in the reviewed literature. We conclude with suggestions for future work along with recommendations for the reporting of essential benchmarking information in current and future textile electrode applications.

Place, publisher, year, edition, pages
London: , 2020
Keywords
smart textiles, textile electrodes, surface electromyography, long-term recording, self-administered
National Category
Medical Materials
Research subject
Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-23066 (URN)10.1177/0040517519858768 (DOI)
Projects
Scan-to-knit - A platform for smart textiles research
Funder
Knowledge Foundation, 20160030
Available from: 2020-03-20 Created: 2020-03-20 Last updated: 2020-04-15Bibliographically approved
Kadi, N., Baghaei, B. & Skrifvars, M. (2019). Effect of Textile structure in the process parameters of thermoplastic bio-composite. Paper presented at 5ième Congrès International Francophone de Mécanique Avancée (CIFMA 2018), Beirut, 31 October - 2 November 2018.. MATEC Web of Conferences, 261(01005), 1-3
Open this publication in new window or tab >>Effect of Textile structure in the process parameters of thermoplastic bio-composite
2019 (English)In: MATEC Web of Conferences, E-ISSN 2261-236X, Vol. 261, no 01005, p. 1-3Article in journal, Editorial material (Other academic) Published
Abstract [en]

Thermoplastic bio-composite have a higher potential of use based on the sustainability benefits. Natural fibres today are a popular choice for applications in biocomposite manufacturing. Hybrid yarns are a satisfactory solution to improve the fabrication of composites containing a thermoplastic matrix and plant-based fibres. Nevertheless, it is still difficult to produce bio-composites with superior mechanical properties, due to problematic impregnation and consolidation results during the production process. This paper investigates the processing parameters for the compression moulding of two different hemp/PLA textiles structure bio-composites (warp knitting and weaving structure). Finite element simulations are used to optimise the processing parameters (pressure, temperature, and time). The results demonstrated that the textile structure has a small effect on the time of production. Main while the pressure and temperature of processing parameters depend only on the type of matrix and the thickness of biocomposite has a big impact on the time of production.

National Category
Engineering and Technology
Research subject
Textiles and Fashion (General); Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-15721 (URN)10.1051/matecconf/201926101005 (DOI)
Conference
5ième Congrès International Francophone de Mécanique Avancée (CIFMA 2018), Beirut, 31 October - 2 November 2018.
Available from: 2019-01-29 Created: 2019-01-29 Last updated: 2019-01-30Bibliographically approved
Jabbari, M., Lundin, M., Bahadorikhalili, S., Skrifvars, M. & Taherzadeh, M. J. (2019). Finding solvent for polyamide 11 using a computer software. Zeitschrift für Physikalische Chemie
Open this publication in new window or tab >>Finding solvent for polyamide 11 using a computer software
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2019 (English)In: Zeitschrift für Physikalische Chemie, ISSN 0942-9352Article in journal (Refereed) Epub ahead of print
Abstract [en]

The solvent finding step has always been a time-consuming job in chemical-involved processes. The source of difficulty mainly comes from the trial-and-errors, as a repetitive process of chosing solvents and mixing them in different proportions. Computers are good at doing repetitive processes; however, they can only deal with numerical values, rather than qulitative scales. Numerification of qualitative parameters (like solubility) has already been introduced. The most recent one is the Hansen solubility parameters (HSPs). Using the HSPs could provide a solvent or solvent-mixture. In our previous study, we introduced a computer-aided model and a software to find a solvent mixture. In this study, we have used the computer-aided solvent selection model to find some solvent mixtures for polyamide 11, a biobased polymer which has attracted enormous attention recently. Using this numerical model significantly diminished the time of solvent development experimentation by decreasing the possible/necessary trials.

Keywords
Hansen solubility parameters, polyamide 11, nylon, solvent mixture, solvent screening, solvent substitution, the Simplex method
National Category
Industrial Biotechnology
Research subject
Resource Recovery; Resource Recovery; Resource Recovery
Identifiers
urn:nbn:se:hb:diva-22385 (URN)10.1515/zpch-2018-1299 (DOI)
Available from: 2020-01-08 Created: 2020-01-08 Last updated: 2020-01-14Bibliographically approved
Kumar Ramamoorthy, S., Åkesson, D., Skrifvars, M., Rajan, R. & Periyasamy, A. P. (2019). Mechanical performance of biofibers and their corresponding composites. In: Mohammad Jawaid, Mohamed Thariq, Naheed Saba (Ed.), Mechanical and Physical Testing of Biocomposites, Fibre-Reinforced Composites and Hybrid Composites: . Woodhead Publishing Limited
Open this publication in new window or tab >>Mechanical performance of biofibers and their corresponding composites
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2019 (English)In: Mechanical and Physical Testing of Biocomposites, Fibre-Reinforced Composites and Hybrid Composites / [ed] Mohammad Jawaid, Mohamed Thariq, Naheed Saba, Woodhead Publishing Limited, 2019Chapter in book (Refereed)
Abstract [en]

This chapter focuses on mechanical performance of biofibers such as flax, hemp, and sisal and their effect on mechanical performance when they are reinforced in thermoset and thermoplastic polymers. The aim of this chapter is to present an overview of the mechanical characterization of the biofibers and their corresponding composites. The mechanical characterization includes tensile, flexural, impact, compressive, shear, toughness, hardness, brittleness, ductility, creep, fatigue, and dynamic mechanical analyses. Detailed studies of each test have been widely reported and an overview is important to relate the studies. Studies pertaining to the topics are cited. The most common materials used in biocomposites are biofibers (also called natural fibers) and petroleum-based polymers such polypropylene. The use of renewable materials in biocomposites has increased in the past couple of decades owing to extensive research on cellulosic fibers and biopolymers based on starch or vegetable oil. Today, research is focused on reinforcing natural fibers in petroleum-based polymers. However, the emphasis is shifting toward the amount of renewable materials in biocomposites, which has led to the use of biopolymers instead of petroleum-based polymers in composites. The mechanical properties of some renewable resource-based composites are comparable to commercially available nonrenewable composites.

Several plant biofibers have been reinforced in thermoplastics or thermosets to manufacture biocomposites because of their specific properties. The Young's modulus of commonly used biofibers such as hemp and flax could be over 50 GPa and therefore they could be good alternatives to glass fibers in several applications. The good mechanical properties of these biofibers influence the composites' mechanical performance when reinforced in polymers. It is important to understand the mechanical performance of these biofibers and biocomposites in a working environment. A detailed discussion about the mechanical performance of commonly used biofibers and composites is provided in this chapter.

Place, publisher, year, edition, pages
Woodhead Publishing Limited, 2019
Keywords
Biocomposite, Biofiber, Mechanical properties, Natural fiber, Renewable materials
National Category
Polymer Technologies Textile, Rubber and Polymeric Materials Other Mechanical Engineering
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-15228 (URN)10.1016/B978-0-08-102292-4.00014-X (DOI)
Available from: 2018-10-22 Created: 2018-10-22 Last updated: 2018-11-16Bibliographically approved
Soroudi, A., Skrifvars, M. & Nierstrasz, V. (2019). Novel Skin-Electrode Conductive Adhesives to Improve the Quality of Recorded Body Signals in Smart Medical Garments. MDPI Proceedings, 32
Open this publication in new window or tab >>Novel Skin-Electrode Conductive Adhesives to Improve the Quality of Recorded Body Signals in Smart Medical Garments
2019 (English)In: MDPI Proceedings, ISSN 2504-3900, Vol. 32Article in journal (Refereed) Published
Abstract [en]

A main barrier to widespread use of electrocardiography garments for long term heart monitoring of elderly and patients is a poor skin-electrode signal transfer because of a high contact impedance and sensitivity to movement. This leads to unwanted disturbances and errors in recorded signals when the patient moves or even breathe, affecting the reliability and quality of the signals especially for patients with dry/old skin. In two different projects at the University of Borås, we have developed two novel products to solve the above problem; (1) an ongoing project that has fabricated a reusable and sustainable electro-conductive adhesive applicable between the skin and high-porous textile electrodes, and (2) a patent-pending skin-electrode glue (BioEl Glue®) which is a biocompatible electro-conductive water-soluble glue used between skin and low-porous textile electrodes.

Keywords
contact impedance, skin electrode interface, textile electrodes, ECG garments, medical garments, electrocardiography garments, smart textile, wearable electronics, wearable ECG
National Category
Polymer Technologies
Research subject
Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-22341 (URN)10.3390/proceedings2019032009 (DOI)
Available from: 2019-12-29 Created: 2019-12-29 Last updated: 2020-06-01Bibliographically approved
Seoane, F., Soroudi, A., Lu, K., Nilsson, D., Nilsson, M., Abtahi, F. & Skrifvars, M. (2019). Textile-Friendly Interconnection between Wearable Measurement Instrumentation and Sensorized Garments—Initial Performance Evaluation for Electrocardiogram Recordings. Sensors, 19(29), 4426
Open this publication in new window or tab >>Textile-Friendly Interconnection between Wearable Measurement Instrumentation and Sensorized Garments—Initial Performance Evaluation for Electrocardiogram Recordings
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2019 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 29, p. 4426-Article in journal (Refereed) Published
Abstract [en]

The interconnection between hard electronics and soft textiles remains a noteworthy challenge in regard to the mass production of textile–electronic integrated products such as sensorized garments. The current solutions for this challenge usually have problems with size, flexibility, cost, or complexity of assembly. In this paper, we present a solution with a stretchable and conductive carbon nanotube (CNT)-based paste for screen printing on a textile substrate to produce interconnectors between electronic instrumentation and a sensorized garment. The prototype connectors were evaluated via electrocardiogram (ECG) recordings using a sensorized textile with integrated textile electrodes. The ECG recordings obtained using the connectors were evaluated for signal quality and heart rate detection performance in comparison to ECG recordings obtained with standard pre-gelled Ag/AgCl electrodes and direct cable connection to the ECG amplifier. The results suggest that the ECG recordings obtained with the CNT paste connector are of equivalent quality to those recorded using a silver paste connector or a direct cable and are suitable for the purpose of heart rate detection.

Keywords
conductive polymers, wearable technology, smart textiles, textile–electronic integration
National Category
Engineering and Technology
Identifiers
urn:nbn:se:hb:diva-23229 (URN)10.3390/s19204426 (DOI)
Available from: 2020-05-25 Created: 2020-05-25 Last updated: 2020-05-28Bibliographically approved
Jabbari, M., Lundin, M., Hatamvand, M., Skrifvars, M. & Taherzadeh, M. J. (2018). Computer-aided theoretical solvent selection using the simplex method based on Hansen solubility parameters. Journal of Information Technology & Software Engineering, 8(4), Article ID 1000242.
Open this publication in new window or tab >>Computer-aided theoretical solvent selection using the simplex method based on Hansen solubility parameters
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2018 (English)In: Journal of Information Technology & Software Engineering, Vol. 8, no 4, article id 1000242Article in journal (Refereed) Published
Abstract [en]

Solvent selection is a crucial step in all solvent-involved processes. Using the Hansen solubility parameters (HSPs)could provide a solvent/solvent-mixture, but there are two main challenges: 1) What solvents should be selected? 2)From each solvent, how much should be added to the mixture? There is no straightforward way to answer the twochallenging questions. This contribution proposes a computer-aided method for selecting solvents (answer to thequestion 1) and finding the adequate amount of each solvent (answer to the question 2) to form a mixture of 2, 3 or4 solvents to dissolve a solute with known HSPs or to replace a solvent. To achieve this, a sophisticated computersoftware package was developed to find the optimized mixture using the mathematical Simplex algorithm based onHSPs values from a database of 234 solvents. To get a list of solvent-mixtures, polyamide66 was tested using itsHSPs. This technique reduces the laboratory effort required in selecting and screening solvent blends while allowinga large number of candidate solvents to be considered for inclusion in a blend. The outcome of this paper significantlydiminished the time of solvent development experimentation by decreasing the possible/necessary trials. Thus, themost suitable solvent/solvent-substitution can be found by the least possible effort; hence, it will save time and costof all solvent-involved processes in the fields of chemistry, polymer and coating industries, chemical engineering, etc.

Keywords
Hansen solubility parameters; Solvent mixture; Solvent substitution; Simplex method, Linear programming, Quadratic minimization, Solvent screening
National Category
Industrial Biotechnology
Research subject
Resource Recovery; Resource Recovery
Identifiers
urn:nbn:se:hb:diva-22384 (URN)10.4172/2165-7866.1000242 (DOI)
Available from: 2020-01-08 Created: 2020-01-08 Last updated: 2020-01-08
Vogt, S., Baghaei, B., Kadi, N. & Skrifvars, M. (2018). Determination of Processing Parameters for Thermoplastic Biocomposites Based on Hybrid Yarns Using Finite Elements Simulation. Journal of Composites Science, 2(1)
Open this publication in new window or tab >>Determination of Processing Parameters for Thermoplastic Biocomposites Based on Hybrid Yarns Using Finite Elements Simulation
2018 (English)In: Journal of Composites Science, ISSN 2504-477X, Vol. 2, no 1Article in journal (Refereed) Published
Abstract [en]

This paper investigates the processing parameters for the compression molding of hemp/PLA hybrid yarn biocomposites and their effect on the final mechanical properties. Finite element simulations are used to develop and assess the processing parameters, pressure, temperature, and time. These parameters are then evaluated experimentally by producing the composites by two different methods, to compare the results of experimentally determined processing conditions to parameters determined by the simulation analysis. The assessment of mechanical properties is done with several experimental tests, showing small improvements for the composites produced with the simulation method. The application of the simulation analysis results in considerably reduced processing times, from the initial 10 min to only three minutes, thereby vastly improving the processing method. While the employed methods are not yet able to produce composites with greatly improved mechanical properties, this study can be seen as a constructive approach, which has the ability to lead to further improvements.

Keywords
fabrics/textiles, mechanical properties, porosity/voids, finite element analysis (FEA)
National Category
Engineering and Technology
Research subject
Textiles and Fashion (General)
Identifiers
urn:nbn:se:hb:diva-13783 (URN)10.3390/jcs2010011 (DOI)
Available from: 2018-03-05 Created: 2018-03-05 Last updated: 2018-03-12Bibliographically approved
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