Related Research Articles
A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. Desiccants for specialized purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules. They are commonly encountered in foods to retain crispness. Industrially, desiccants are widely used to control the level of water in gas streams.
Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. In other words, it might refer to whether a commodity should no longer be on a pantry shelf, or no longer on a supermarket shelf. It applies to cosmetics, foods and beverages, medical devices, medicines, explosives, pharmaceutical drugs, chemicals, tyres, batteries, and many other perishable items. In some regions, an advisory best before, mandatory use by or freshness date is required on packaged perishable foods. The concept of expiration date is related but legally distinct in some jurisdictions.
Waterproofing is the process of making an object, person or structure waterproof or water-resistant so that it remains relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or underwater to specified depths.
Waterproof fabrics are fabrics that are, inherently, or have been treated to become, resistant to penetration by water and wetting. The term "waterproof" refers to conformance to a governing specification and specific conditions of a laboratory test method. They are usually natural or synthetic fabrics that are laminated or coated with a waterproofing material such as wax, rubber, polyvinyl chloride (PVC), polyurethane (PU), silicone elastomer, or fluoropolymers. Treatment could be either of the fabric during manufacture or of completed products after manufacture, for instance by a waterproofing spray. Examples include the rubberized fabric used in Mackintosh jackets, sauna suits, and inflatable boats.
A vapor barrier is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through the wall, floor, ceiling, or roof assemblies of buildings and of packaging to prevent interstitial condensation. Technically, many of these materials are only vapor retarders as they have varying degrees of permeability.
A blister pack is any of several types of pre-formed plastic packaging used for small consumer goods, foods, and for pharmaceuticals.
Oxygen transmission rate (OTR) is the measurement of the amount of oxygen gas that passes through a substance over a given period. It is mostly carried out on non-porous materials, where the mode of transport is diffusion, but there are a growing number of applications where the transmission rate also depends on flow through apertures of some description.
Carbon dioxide transmission rate (COTR) is the measurement of the amount of carbon dioxide gas that passes through a substance over a given period. It is mostly carried out on non-porous materials, where the mode of transport is diffusion, but there are a growing number of applications where the transmission rate also depends on flow through apertures of some description.
In physics and engineering, permeation is the penetration of a permeate through a solid. It is directly related to the concentration gradient of the permeate, a material's intrinsic permeability, and the materials' mass diffusivity. Permeation is modeled by equations such as Fick's laws of diffusion, and can be measured using tools such as a minipermeameter.
The relationship between water content and equilibrium relative humidity of a material can be displayed graphically by a curve, the so-called moisture sorption isotherm. For each humidity value, a sorption isotherm indicates the corresponding water content value at a given temperature. If the composition or quality of the material changes, then its sorption behaviour also changes. Because of the complexity of sorption process the isotherms cannot be determined explicitly by calculation, but must be recorded experimentally for each product.
Damp proofing in construction is a type of moisture control applied to building walls and floors to prevent moisture from passing into the interior spaces. Dampness problems are among the most frequent problems encountered in residences.
Moisture analysis covers a variety of methods for measuring the moisture content in solids, liquids, or gases. For example, moisture is a common specification in commercial food production. There are many applications where trace moisture measurements are necessary for manufacturing and process quality assurance. Trace moisture in solids must be known in processes involving plastics, pharmaceuticals and heat treatment. Fields that require moisture measurement in gasses or liquids include hydrocarbon processing, pure semiconductor gases, bulk pure or mixed gases, dielectric gases such as those in transformers and power plants, and natural gas pipeline transport. Moisture content measurements can be reported in multiple units, such as: parts per million, pounds of water per million standard cubic feet of gas, mass of water vapor per unit volume or mass of water vapor per unit mass of dry gas.
Food packaging is a packaging system specifically designed for food and represents one of the most important aspects among the processes involved in the food industry, as it provides protection from chemical, biological and physical alterations. The main goal of food packaging is to provide a practical means of protecting and delivering food goods at a reasonable cost while meeting the needs and expectations of both consumers and industries. Additionally, current trends like sustainability, environmental impact reduction, and shelf-life extension have gradually become among the most important aspects in designing a packaging system.
Air barriers control air leakage into and out of the building envelope. Air barrier products may take several forms:
Breathability is the ability of a fabric to allow moisture vapor to be transmitted through the material.
A gas pycnometer is a laboratory device used for measuring the density—or, more accurately, the volume—of solids, be they regularly shaped, porous or non-porous, monolithic, powdered, granular or in some way comminuted, employing some method of gas displacement and the volume:pressure relationship known as Boyle's law. A gas pycnometer is also sometimes referred to as a helium pycnometer.
Dynamic vapor sorption (DVS) is a gravimetric technique that measures how quickly and how much of a solvent is absorbed by a sample such as a dry powder absorbing water. It does this by varying the vapor concentration surrounding the sample and measuring the change in mass which this produces. The technique is mostly used for water vapor, but is suitable for a wide range of organic solvents. Daryl Williams, founder of Surface Measurement Systems Ltd, developed Dynamic Vapor Sorption in 1991; the first instrument was delivered to Pfizer UK in 1992. DVS was originally developed to replace the time and labor-intensive desiccators and saturated salt solutions used to measure water vapor sorption isotherms.
Package testing or packaging testing involves the measurement of a characteristic or property involved with packaging. This includes packaging materials, packaging components, primary packages, shipping containers, and unit loads, as well as the associated processes.
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.
References
- ↑ Stevens, Michelle; Tuomela, Stephen; Mayer, Dan. "Water Vapor Permeation Testing of Ultra-Barriers: Limitations of Current Methods and Advancements Resulting in Increased Sensitivity" (PDF). Archived from the original (PDF) on 2014-04-13. Retrieved 2014-04-10.
- ↑ "Singapore research produces world's best protection from moisture and oxygen" (PDF). Institute of Materials Research and Engineering (Press release). 29 April 2008.
- ↑ "Water Vapour Transmission Rate Measurements". npl.co.uk. 1 June 2011. Archived from the original on 13 April 2014.
- ↑ Nisato, G. (September 2002). "Permeation Methods, Deliverable D5b FLEXled-phr-0209-009/Public Report" (PDF).[ dead link ]
- ↑ "Electrical Calcium Test for Measuring Barrier Permeability". National Renewable Energy Laboratory. Archived from the original on 2014-04-13.
- ↑ "ASTM D7709 - 12(2017) Standard Test Methods for Measuring Water Vapor Transmission Rate (WVTR) of Pharmaceutical Bottles and Blisters".