Description:

Non destructive testing NDT) are noninvasive techniques to determine the integrity of a material, component or structure or quantitatively measure some characteristic of an object. In contrast to destructive testing, NDT is an assessment without doing harm, stress or destroying the test object. The destruction of the test object usually makes destructive testing more costly and it is also inappropriate in many circumstances.

NDT plays a crucial role in ensuring cost effective operation, safety and reliability of plant, with resultant benefit to the community. NDT is used in a wide range of industrial areas and is used at almost any stage in the production or life cycle of many components. The mainstream applications are in aerospace, power generation, automotive, railway, petrochemical and pipeline markets. NDT of welds is one of the most used applications. It is very difficult to weld or mold a solid object that has no risk of breaking in service, so testing at manufacture and during use is often essential.

While originally NDT was applied only for safety reasons it is today widely accepted as cost saving technique in the quality assurance process. Unfortunately NDT is still not used in many areas where human life or ecology is in danger. Some may prefer to pay the lower costs of claims after an accident than applying of NDT. That is a form of unacceptable risk management. Disasters like the railway accident in Eschede Germany in 1998 is only one example, there are many others.

For implementation of NDT it is important to describe what shall be found and what to reject. A completely flawless production is almost never possible. For this reason testing specifications are indispensable. Nowadays there exists a great number of standards and acceptance regulations. They describe the limit between good and bad conditions, but also often which specific NDT method has to be used.

The reliability of an NDT Method is an essential issue. But a comparison of methods is only significant if it is referring to the same task. Each NDT method has its own set of advantages and disadvantages and, therefore, some are better suited than others for a particular application. By use of artificial flaws, the threshold of the sensitivity of a testing system has to be determined. If the the sensitivity is to low defective test objects are not always recognized. If the sensitivity is too high parts with smaller flaws are rejected which would have been of no consequence to the serviceability of the component. With statistical methods it is possible to look closer into the field of uncertainly. Methods such as Probability of Detection (POD) or the ROC-method "Relative Operating Characteristics" are examples of the statistical analysis methods. Also the aspect of human errors has to be taken into account when determining the overall reliability.

Personnel Qualification is an important aspect of non-destructive evaluation. NDT techniques rely heavily on human skill and knowledge for the correct assessment and interpretation of test results. Proper and adequate training and certification of NDT personnel is therefore a must to ensure that the capabilities of the techniques are fully exploited. There are a number of published international and regional standards covering the certification of competence of personnel. The EN 473 (Qualification and certification of NDT personnel - General Principles) was developed specifically for the European Union for which the SNT-TC-1A is the American equivalent.

The nine most common NDT Methods are shown in the main index of this encyclopedia. In order of most used, they are: Ultrasonic Testing (UT), Radiographic Testing (RT), Electromagnetic Testing (ET) in which Eddy Current Testing (ECT) is well know and Acoustic Emission (AE or AET). Besides the main NDT methods a lot of other NDT techniques are available, such as Shearography Holography, Microwave and many more and new methods are being constantly researched and developed.

NDT Applications and Limitations

NDT Method	Applications	Limitations
Liquid Penetrant	used on nonporous materials can be applied to welds, tubing, brazing, castings, billets, forgings, aluminium parts, turbine blades and disks, gears	need access to test surface defects must be surface breaking decontamination & precleaning of test surface may be needed vapour hazard very tight and shallow defects difficult to find depth of flaw not indicated
Magnetic Particle	ferromagnetic materials surface and slightly subsurface flaws can be detected can be applied to welds, tubing, bars, castings, billets, forgings, extrusions, engine components, shafts and gears	detection of flaws limited by field strength and direction needs clean and relatively smooth surface some holding fixtures required for some magnetizing techniques test piece may need demagnetization which can be difficult for some shapes and magetizations depth of flaw not indicated
Eddy Current	metals, alloys and electroconductors sorting materials surface and slightly subsurface flaws can be detected used on tubing, wire, bearings, rails, nonmetal coatings, aircraft components, turbine blades and disks, automotive transmission shafts	requires customized probe although non-contacting it requires close proximity of probe to part low penetration (typically 5mm) false indications due to uncontrolled parametric variables
Ultrasonics	metals, nonmetals and composites surface and slightly subsurface flaws can be detected can be applied to welds, tubing, joints, castings, billets, forgings, shafts, structural components, concrete, pressure vessels, aircraft and engine components used to determine thickness and mechanical properties monitoring service wear and deterioration	usually contacting, either direct or with intervening medium required (e.g. immersion testing) special probes are required for applications sensitivity limited by frequency used and some materials cause significant scattering scattering by test material structure can cause false indications not easily applied to very thin materials
Radiography Neutron	metals, nonmetals, composites and mixed materials used on pyrotechnics, resins, plastics, organic material, honeycomb structures, radioactive material, high density materials, and materials containing hydrogen	access for placing test piece between source and detectors size of neutron source housing is very large (reactors) for reasonable source strengths collimating, filtering or otherwise modifying beam is difficult radiation hazards cracks must be oriented parallel to beam for detection sensitivity decreases with increasing thickness
Radiography X-ray	metals, nonmetals, composites and mixed materials used on all shapes and forms; castings, welds, electronic assemblies, aerospace, marine and automotive components	access to both sides of test piece needed voltage, focal spot size and exposure time critical radiation hazards cracks must be oriented parallel to beam for detection sensitivity decreases with increasing thickness
Radiography Gamma	usually used on dense or thick material used on all shapes and forms; castings, welds, electronic assemblies, aerospace, marine and automotive components used where thickness or access limits X-ray generators	radiation hazards cracks must be oriented parallel to beam for detection sensitivity decreases with increasing thickness access to both sides of test piece needed not as sensitive as X-rays

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Truck modification has been increasingly popular nowadays. Heavy modification is not limited on cars you see on the streets everyday; it is very much applicable to rigs as well. However, why do people modify their cars? It does not take a genius to find out why people put accessories or change the original look of their trucks. It is very clear that modifying trucks or SUVs mainly fall on two reasons: beautification and improvement of performance.

There are many ways to improve your automobiles. There are parts and accessories that can really help you increase the functionality of your vehicles. However, not everything may be available to the kind of vehicle that you have. There will always be an appropriate part or accessory for every kind of SUV. All of these items allow you to change the interiors to make it more comfortable while you are traveling. You can also add parts on the exterior to make your vehicle heavy duty. However, in changing the way your vehicle looks, you will still have to question whether if it is solely for looks, performance or both.

Some people really want to make their car to be loud that it can turn the heads of many people as it passes by through the streets. The loudness does not only come from the sound system that you have installed. Your SUVs can be a real head turner right from the colors of the paint you choose right down to the Tuff Country lift kits you have installed. Whatever you do with you them, just as long as you have monster trucks, it will really be attractive for many people. Therefore, most of the modifications for looks always end up making the truck look bigger than usual.

While others are concerned on how their trucks or SUVs can look like, some people are concerned with performance. It is undeniable that if you use your trucks or SUVs for work or traveling, you will definitely opt for accessories that will make them withstand the different factors that could affect the speed that they have. Modifications made on engines, break linings, tires and the chassis can be done to enhance the performance of the vehicle. Honestly speaking, this may be more expensive compared to adapting a change for the looks alone. However, if it is a necessity, it is worth the investment. You can do anything with it just to be more efficient and comfortable as you travel for work or pleasure. You know that your vehicles will stand tall no matter how uneven the surface of the road that you will be traveling.

Everyone can have their trucks or SUVs modified as early as the first time that they purchased it. You will have an option to change their color, make it more comfortable, or even make it bigger through installation of Tuff Country lift kits. To have the best modification for your vehicle, ask yourself, why you want that change. What you put in them can really improve the way it looks or improve their performance.

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Multi-chamber IV bag has two categories: fluid multi-chamber IV bag and fluid-powder multi-chamber IV bag. It’s defined as the separate storage of different medicine in different sub-chambers by weldingduring production, storage and transportation. In application, the separate sub-chambers are connected by external forces, and the contents are mixed. Multi-chamber IV bag is mainly used for the contents that are unstable after mixing, and can not guarantee long term storage. This article analyzes the testing of two key factors for multi-chamber IV bags: welding and barrier property.

1.The Analysis and Testing of Welding Strength

For the welding strength of multi-chamber IV bag, its convenience, safety and protection for isolated contents during storage and transportation must be maintained. Therefore, multi-chamber welding process control is the key procedure in the whole production. Welding is determined by three indexes: temperature, time and pressure. Multi-chamber IV bags, to achieve safe storage and transportation as well as easy clinical operation, can only maintain a mediate welding strength, which is also called heat seal strength. How to control this index successfully is a focus for multi-chamber IV bag manufacturers.

Labthink HST-H3 Heat Seal Tester and XLW (PC) Auto Tensile Tester are the professional testers for multi-chamber IV bag and its indexes. When testing the finished multi-chamber IV bags, a specimen of the welding place is prepared. This specimen can be automatically tested after clamping and pressing the ‘heat seal’ button on XLW (PC). Besides, for the proper welding strength, the manufacturer needs to make researches on temperature, time and pressure. HST-H3 Heat Seal Tester can be applied with the auto tensile tester for the best heat seal temperature, time and pressure indexes.

2.The Analysis and Testing of Barrier

Barrier property is the most important factor affecting the quality of fluid and fluid-powder multi-chamber IV bags. Owing to the low barrier property of the content contact package, a barrier package is needed for prevention of oxygen and moisture permeation. Besides, nitrogen is applied to take place of the air between the inner package and barrier package. Therefore, oxygen transmission as well as nitrogen and moisture transmission should be tested. Labthink VAC-V series of differential pressure gas permeation testers can accomplish relevant testing.

The application of multi-chamber IV bags is the great development of IV bags. As the most strictly required package for medicine, its tensile strength, elongation, heat seal strength, puncture performance of film and closure and seal property all need to be tested. Labthink, as the excellent provider of testing instruments and services, has been providing most excellent and thorough quality control solutions for the global medical industry. Labthink is willing to have more communication and cooperation will pharmaceutical companies and institutions

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