Elena Codău - Academia.edu (original) (raw)

Papers by Elena Codău

Journal of The Textile Institute, Jan 17, 2022

Journal of The Textile Institute, Apr 14, 2023

Over the last decade, modeling of heat and mass transfer through textile materials has become a c... more Over the last decade, modeling of heat and mass transfer through textile materials has become a constant concern of researchers and has been directly influenced by the development of computing systems. The importance of heat and moisture transfer properties of clothing is in particular crucial in high-risk professions like firefighting or sportswear. While some analytical and numerical models have been developed about these materials, the most approaches are at the macroscopic level, where microscopic details are filtered out to reduce numerical and physical complexity. When unsteady transfer occurs the results can have significant errors. On the other hand, the simulation is a cheaper method to obtain the static or dynamic characteristics of porous materials. The goal of this paper is to model a simple textile structure and to perform a water vapour diffusion simulation using the Comsol Multiphysics(R). Comsol(R) is a software environment that allows the simulation of physical phenomena using the geometric models. The appropriate module for water vapour transfer is the Transport of Diluted Species. By applying the standard boundary conditions a comparison between the simulated and experimental value can be made. In order to have a significant results for entire system the dimension of sample was chosen so that it becomes a Representative Elementary Volume. Starting from the properties of the yarns and a geometric model of the textile structure, by simulation were acquired the global characteristics of the material such as: evaporation resistance, porosity, diffusion coefficient, diffusion flux, tortuosity and relative times for which the transfer becomes stationary. Global values were obtained by volumetric average methode, using predefined functions in Comsol(R).

Journal of The Textile Institute, Jan 2, 2015

ABSTRACT Thermal comfort ofﬁreﬁghters is strongly dependent on moisture management of clothing la... more ABSTRACT Thermal comfort ofﬁreﬁghters is strongly dependent on moisture management of clothing layers closest to the skin. This study centers on liquid moisture and moisture vapor transfer across various types of underwear fabrics and innermost layers of theﬁreﬁghter intervention jacket (linings). Importance of the underwear neighboring layer in liquid moisture and moisture vapor transfer and hence, in thermal comfort of aﬁreﬁghter is underlined and discussed. Moisture management tester is employed as an efﬁcient tool in evaluating a transfer of liquid moisture not only through individual underwear fabric but also through bi-layers underwear lining. Moisture vapor transfer properties of mono- and bi-layer fabrics were investigated by evaporative dish method. The results show that moisture management performances of tested mono- and bi-layer fabrics are related to their composition and the general physical properties. Composition of both underwear and lining has a crucial impact on liquid moisture transfer through bi-layers. Transfer of moisture vapor is mainly governed by fabric physical properties. Combination of natural and syntheticﬁbers results in best performing fabrics with regard to the moisture management.

In the last years an increasing improvement in qualitative standards of human lifestyles determin... more In the last years an increasing improvement in qualitative standards of human lifestyles determined a greater sense of comfort for the textiles used in indoor and outdoor activities. These textiles must fulfill the consumer requirements of comfort, fit and easy of movement. New fibres have been produced and many studies are carrying on for fabric structure optimization in order to obtain functional products. This paper presents a study made with the purpose of understanding the effect of stitch length and structure on the dimensional, thermal, air and water vapour permeability properties of knitted fabrics made of Seacell® and elastane yarns, for active sportswear applications. The results demonstrate that the thermo-physiological comfort properties such as air permeability and thermal properties can be changed by fabric construction. The loop length significantly influences these properties of the fabrics, especially air permeability and thermal conductivity. Single jersey structure is the preferred candidate for the development of the active sportswear envisaged due to better performance, particularly in terms of water vapor and air permeability.Fundação para a Ciência e a Tecnologia (FCT) - Ciência 2008 Progra

Autex Research Journal, Mar 1, 2015

Journal of Industrial Textiles, Apr 7, 2014

The goal of this research is to develop a mathematical model of heat transfer in protective garme... more The goal of this research is to develop a mathematical model of heat transfer in protective garments exposed to routine fire environment (low level of radiant heat flux) in order to establish systematic basis for engineering materials and garments for optimum thermal protective performance and comfort. In the first stage, this paper focuses on the formulation of heat transfer model suitable for predicting temperature and heat flux in firefighter protective clothing, using COMSOL Multiphysics® package based on the finite element method. Computational results show the time variation of the temperature at the inner face of the protective clothing system during the exposure to a low-radiant heat flux as well as during the cooling-down period. Model predictions of the temperature agreed very well with the experimental temperature. In the second stage of this study, in order to predict the first and second-degree burns, the model of heat transfer through multilayer protective system was coupled with the heat transfer model in the skin. The Pennes model was used to model heat transfer in the living tissue. The duration of exposure during which the garment protects the firefighter from getting first and second-degree burns is numerically predicted using Henriques equation. The results demonstrated that even for a low-level thermal radiant heat flux, a typical three-layer thermal protective clothing system is required to protect the wearer from skin burn injury.

Journal of Engineered Fibers and Fabrics, Dec 1, 2011

This paper studies the influence of fabric's structure on the thermal and moisture management pro... more This paper studies the influence of fabric's structure on the thermal and moisture management properties of knitted fabrics made of two types of yarns with thermo-regulating effect: Coolmax ® and Outlast ®. The main purpose of this study was the selection of the most adequate fabric, to be used in summer and winter sportswear. The results demonstrated that some properties, such as, thermal properties, diffusion ability, air and water vapor permeability are influenced by both raw material type and knitted structure parameters. Wicking ability is influenced to a greater extent by the knitted structure, while the drying ability is primarily determined by raw material and to a lesser extent by the knitted structure parameters. Outlast ® fabrics are preferred candidates for warmer climate sportswear, particularly due to their lower thermal resistance, higher thermal conductivity and absorptivity, air and water vapor permeability. When considering sportswear for colder weather, Coolmax ® based structures seem to be the best choice. These findings are an important tool in the design of a sportswear product tailored to the different body areas thermal and moisture management requirements.

Energies

The need for reducing fossil fuel consumption and greenhouse gas (GHG) emissions in internal comb... more The need for reducing fossil fuel consumption and greenhouse gas (GHG) emissions in internal combustion engines has raised the opportunity for the use of renewable energy sources. For the progressive replacement of fossil fuels like diesel, those derived from the sustainable management of forest resources may be a good option. In Portugal, pine trees (pinus pinaster) are among the most widely cultivated tree species. Turpentine can be extracted from their sap without harming the tree. Turpentine is known to be a good fuel with a lower viscosity than regular diesel but with a comparable caloric value, boiling point and ignition characteristics, although it is not widely used as a compression ignition fuel. Moreover, recent research has highlighted the possibility of substantially increasing the turpentine yield through biotechnology, bringing it closer to economic viability. The present study investigates the performance, pollutant emissions and fuel consumption of a 1.6 L four-cylin...

Sciendo eBooks, Feb 8, 2023

Bio-active" textiles belong to the so-called "Functional" textiles that in addition to their basi... more Bio-active" textiles belong to the so-called "Functional" textiles that in addition to their basic functions claim to take care of the health and hygiene of the consumer contributing to his well-being. Fabric characteristics are usually dictated by a specified end-use. Understanding the relationship between the fabric end-use and fabric properties becomes fundamental for classification, selection, and proper utilization of apparel fabrics. This study focused on the effect of knitted structures on SeaCell active/Lycra yarn knitted fabric properties. In this work, we have used three structures: single jersey, single piqué and double piqué, for production of the knitted fabrics.

Textile Research Journal, Jul 22, 2016

This paper describes the concept of creating and testing of a textile heat flow sensor in order t... more This paper describes the concept of creating and testing of a textile heat flow sensor in order to determine the amount of heat exchanged between the human body and its environment. The main advantage of this sensor is the permeability to moisture, which allows taking into account the evaporation phenomenon, contrary to the traditional heat flow sensors. Another property related to this new sensor is its flexibility conferred by the textile substrate, which allows it to be applied on deformable surfaces.

Textile Research Journal, 2016

Journal of Engineered Fibers and Fabrics

Research Journal of Textile and Apparel, 2004

ABSTRACT Weaving process efficiency is determined by factors that take into account the technical... more ABSTRACT Weaving process efficiency is determined by factors that take into account the technical condition of the weaving machine, the quality of the used yarns, the workers’ qualification and the climatic conditions. The breakage number of warp and weft yarns for every one meter of woven fabric or during unit time exerts a significant influence on a weaving machine’s efficiency. Forecasting breakage number can be determined using different methods. Some of these methods are applied after assembling the article on the weaving machine, while others are applied before that stage. The forecast of yarn behaviour on the weaving process can be expressed using calculated indexes considering specific elements of yarn stress distribution and breaking strength. The values of these indexes allow one to forecast warp and weft weaving processability and make better decisions in refusing yarns that cannot guaranty suitable efficiency.

ABSTRACT The goal of this research is to develop a numerical model of heat transfer in protective... more ABSTRACT The goal of this research is to develop a numerical model of heat transfer in protective garments exposed to low levels of radiant heat flux. Comsol Multiphysics® engineering simulation software was used as a tool for modeling of heat transfer through the given multilayer textile structure. Validation of the heat transfer model was done by comparison with the experimental data. The first results are quite in good agreement with the corresponding experimental measurements. This study is the first in a series of studies on optimizing the performance of firefighter clothing, in respect of thermal comfort and skin protection from thermal injury that results from exposure to low-intensity thermal radiation.

Sensors and Actuators A: Physical, 2015