The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by , , or and is measured in W·m−1·K−1.
The R-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat, in the context of construction. R-value is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions. The measure is therefore equally relevant for lowering energy bills for heating in the winter, for cooling in the summer, and for general comfort.
A heat sink is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with other high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light-emitting diodes (LEDs), where the heat dissipation ability of the component itself is insufficient to moderate its temperature.
A radiant barrier is a type of building material that reflects thermal radiation and reduces heat transfer. Because thermal energy is also transferred by conduction and convection, in addition to radiation, radiant barriers are often supplemented with thermal insulation that slows down heat transfer by conduction or convection.
A duvet, usually called a comforter or (down-filled) quilt in American English, and a doona in Australian English, is a type of bedding consisting of a soft flat bag filled with either down, feathers, wool, cotton, silk, or a synthetic alternative, and is typically protected with a removable cover, analogous to a pillow and pillow case. The term duvet is mainly British, especially in reference to the bedding; rarely used in US English, it often refers to the cover. Sleepers often use a duvet without a top bed sheet, as the duvet cover can readily be removed and laundered as often as the bottom sheet.
A heating element is a device used for conversion of electric energy into heat, consisting of a heating resistor and accessories. Heat is generated by the passage of electric current through a resistor through a process known as Joule heating. Heating elements are used in household appliances, industrial equipment, and scientific instruments enabling them to perform tasks such as cooking, warming, or maintaining specific temperatures higher than the ambient.
A label is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product, on which is written or printed information or symbols about the product or item. Information printed directly on a container or article can also be considered labelling.
Moisture vapor transmission rate (MVTR), also water vapor transmission rate (WVTR), is a measure of the passage of water vapor through a substance. It is a measure of the permeability for vapor barriers.
A heat flux sensor is a transducer that generates an electrical signal proportional to the total heat rate applied to the surface of the sensor. The measured heat rate is divided by the surface area of the sensor to determine the heat flux.
There are a number of possible ways to measure thermal conductivity, each of them suitable for a limited range of materials, depending on the thermal properties and the medium temperature. Three classes of methods exist to measure the thermal conductivity of a sample: steady-state, time-domain, and frequency-domain methods.
Abrasion is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Abrasion can be an undesirable effect of exposure to normal use or exposure to the elements.
In heat transfer, thermal engineering, and thermodynamics, thermal conductance and thermal resistance are fundamental concepts that describe the ability of materials or systems to conduct heat and the opposition they offer to the heat current. The ability to manipulate these properties allows engineers to control temperature gradient, prevent thermal shock, and maximize the efficiency of thermal systems. Furthermore, these principles find applications in a multitude of fields, including materials science, mechanical engineering, electronics, and energy management. Knowledge of these principles is crucial in various scientific, engineering, and everyday applications, from designing efficient temperature control, thermal insulation, and thermal management in industrial processes to optimizing the performance of electronic devices.
Dimensional stability pertains to a fabric's ability to maintain its initial size and shape even after undergoing wear and care, which is a desirable property. Textile manufacturing is based on the conversion of fiber into yarn, yarn into fabric, includes spinning, weaving, or knitting, etc. The fabric passes through many inevitable changes and mechanical forces during this journey. When the products are immersed in water, the water acts as a relaxing medium, and all stresses and strains are relaxed and the fabric tries to come back to its original state.
Comfort is a sense of physical or psychological ease, often characterised as a lack of hardship. Persons who are lacking in comfort are uncomfortable, or experiencing discomfort. A degree of psychological comfort can be achieved by recreating experiences that are associated with pleasant memories, such as engaging in familiar activities, maintaining the presence of familiar objects, and consumption of comfort foods. Comfort is a particular concern in health care, as providing comfort to the sick and injured is one goal of healthcare, and can facilitate recovery. Persons who are surrounded with things that provide psychological comfort may be described as being "in their comfort zone". Because of the personal nature of positive associations, psychological comfort is highly subjective.
Clothing insulation is the thermal insulation provided by clothing.
The thermal manikin is a human model designed for scientific testing of thermal environments without the risk or inaccuracies inherent in human subject testing. Thermal manikins are primarily used in automotive, indoor environment, outdoor environment, military and clothing research. The first thermal manikins in the 1940s were developed by the US Army and consisted of one whole-body sampling zone. Modern-day manikins can have over 30 individually controlled zones. Each zone contains a heating element and temperature sensors within the “skin” of the manikin. This allows the control software to heat the manikin to a normal human body temperature, while logging the amount of power necessary to do so in each zone and the temperature of that zone.
ANSI/ASHRAE Standard 55: Thermal Environmental Conditions for Human Occupancy is an American National Standard published by ASHRAE that establishes the ranges of indoor environmental conditions to achieve acceptable thermal comfort for occupants of buildings. It was first published in 1966, and since 2004 has been updated every three to six years. The most recent version of the standard was published in 2023.
Textile performance, also known as fitness for purpose, is a textile's capacity to withstand various conditions, environments, and hazards, qualifying it for particular uses. The performance of textile products influences their appearance, comfort, durability, and protection.
The different textile applications require a different set of performance parameters. As a result, the specifications determine the level of performance of a textile product. Textile testing certifies the product's conformity to buying specification. It also describes product manufactured for non-aesthetic purposes, where fitness for purpose is the primary criterion. Engineering of high-performance fabrics presents a unique set of challenges.
Textile testing is the process of measuring the properties and performance of textile materials—textile testing includes physical and chemical testing of raw materials to finished products.
Clothing physiology is a branch of science that studies the interaction between clothing and the human body, with a particular focus on how clothing affects the physiological and psychological responses of individuals to different environmental conditions. The goal of clothing physiology research is to develop a better understanding of how clothing can be designed to optimize comfort, performance, and protection for individuals in various settings, including outdoor recreation, occupational environments, and medical contexts.
