Blister-detection

A configuration frequently used in cyclic stress testing is the reduced area adhesive bond (RAAB) specimen. This is similar to the blister detection specimen, but is 1/2 inch wide and a 1/4-inch hole is drilled through the center of the overlap region this provides more environmental exposure of the bondline. Potter has reported using RAAB specimens to compare the durabilities of several modified epoxy adhesives.Specimens subjected to cyclic stressing failed in fewer hours than specimens held at a constant stress, even when cycled at a lower stress level. He also found that a slow cyclic rate was more damaging than a fast cyclic rate. 

Blister Detection Large area metal-to-metal bonding to ascertain adhesive flow characteristics during bonding. Conventional lap shear specimens are machined from the bonded sheet and are tested. The specimens are examined for evidence of air entrapment ( blistering ). 

Ultrasonic techniques. Wall thickness can be measured to monitor the progress of general corrosion, cracks can be detected and hydrogen blisters identified. Certain construction materials such as cast iron cannot be examined by ultrasound. Skilled operators and specialist equipment is required. Plant can be examined in situ except when it is above 80°C. 

B 977 525 354 2.44 14 Blistering was detected with ultrasonic examination in catalytic reformer piping. Metallography indicated surface decarburization and blistering at non-metallic inclusions, with intergranular cracks growing from the blisters. Cr content was 1.10 percent. 

Description Conventional wet fluorescent AC yoke magnetic particle inspection used for detection of cracks at a surface. Blending the welds and sanding smooth increases sensitivity. Polish and etch as in a creep evaluation looking for microscopic damage. Replicas can be taken for laboratory analysis. Conventional radiography used to inspect welds for cracks. Internal visual inspection of pressure vessels for surface blistering. Monitors the sound that cracks emit when they are stressed. 

Detection Capability Can detect HTHA only after cracks have formed. Cannot detect microscopic damage. Can detect and distinguish microfissuring and micro voids due to HTHA from other indications very reliably. Can detect HTHA only after macro size cracks have formed. Cannot detect microscopic damage. Blisters are readily apparent when present. However, HTHA may frequently occur without the formation of surface blisters. Reported to be capable of detecting cracks. Currently not known whether microscopic damage can be detected. 

Clear, colorless to yellowish, somewhat oily liquid that has a fruity but biting and irritating odor that is detectable at approximately 0.14 ppm. Vapor is irritating to both eyes and skin. Vapor concentrations that will produce blisters are hard to obtain in an open area. 

Clinical signs and symptoms from mustard (H/HD) are not apparent until hours later skin blisters might not appear for up to twenty-four hours, but tissue damage occurs within two minutes. If decontamination is not done within the first two minutes after exposure, nothing can be done to prevent a mustard injury. Since mustard (H/HD) can be detected by human beings by smell in concentrations of 0.6 to 1.0 mg/m3 as a garlic, horseradish, or mustard odor an alert person will most likely smell the mustard vapor before encountering the liquid. 

Improved (Chemical Agent) Point Detection System (IPDS) This detection system is a new shipboard point detector and alarm that replaces the chemical Agent Point Detection System. This system can detect nerve and blister agent vapors at low levels and automatically provides an alarm to the ship. 

Individual Chemical Agent Detector (ICAD) A miniature lightweight chemical agent detector that can be worn by an individual. It detects and alarms to nerve, blood, choking, and blister agents and is intended for a variety of applications. It may be used as a point detector. 

Joint Chemical Agent Detector (JCAD) This detector will employ surface acoustic wave technology to detect nerve and blister agents. It will also allow detection of new forms of nerve agents. 

M9 Chemical Detection Paper A self-adhesive paper that can be readily attached to the body or to vehicles, shelters, and other equipment. It cannot distinguish the identity of agents. The agent sensitive dye will turn red upon contact with liquid nerve agents (G and V) and blister agents (H and L). The paper produces colored spots when in contact with nerve and blister agents. 

M256-Series Chemical Agent Detector Kit A kit used by military personnel to detect and identify field concentrations of nerve, blister or blood agent vapors. The kit consists of twelve samplers/detectors and a packet of M8 detector paper. It is used at the squad, crew or section level to detect and identify field concentrations of nerve, blister or blood agents vapors. It is usually used to determine when it is safe to unmask, to locate and identify chemical hazards, and to monitor decontamination effectiveness. 

A wide variety of commercial equipment is available for detection of hazardous chemicals, including a number of chemical warfare agents. For example, ion mobility spectroscopy is used to detect nerve, blister, and blood agents. The Chemical Agent Monitor is a portable, hand-held point detection instrument that uses ion mobility spectrometry to monitor nerve or blister agent vapors. However, minimum detection limits are approximately 100 times the acceptable exposure limit for nerve agents, and approximately 50 times the acceptable exposure limit for blister agents. 

Acoustic wave sensors are also used to detect nerve and blister agents. The surface acoustic wave chemical agent detector (SAW Mini-CAD) is a commercially available, pocket-sized instrument that can monitor for trace levels of toxic vapors of sulfur-based mustard agents (e.g., distilled mustard) and G nerve agents (e.g., tabun, sarin, soman) with a high degree of specificity. Colorimetric tubes are the... 

Additional detectors currently available use other technologies such as electrochemical detectors for blister, nerve, blood, and choking agents, and infrared spectroscopy detectors or photo ionization detectors for the detection of blister and nerve... 

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