The Scintillation Camera
Michael Ljungberg in Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
The imaging couch is constructed from a material with low attenuating properties, such as carbon fibre, to ensure its presence does not adversely affect the scintigraphic image. The couch should be sufficiently strong to avoid sagging when fully extended. For hybrid systems containing both SPECT and CT imaging modalities, a sub-pallet is often required to ensure sufficient support is available to further extend the imaging couch beyond the gamma camera field of view and into the CT gantry. The sub-pallet does not have the same low-attenuation properties of the imaging couch, and care should be taken to ensure it is not present within the imaging field of view during an acquisition.
Other Preventive Methods
J G Webster in Prevention of Pressure Sores, 2019
Sutton et al used pads made of highly structured carbon fibers of about 9 μm in diameter. These were made by carbonizing polyacrylonitrile fibers. Preclinical animal experiments showed that the stress–strain behavior of the pads matched that of the skin within 8 weeks (figure 13.4). In addition, histological examination revealed healthy collagen fibers intertwined with carbon fibers within the implanted pad, and no carbon was found in the paraaortic or lymph nodes. Sutton et al reported the insertion of carbon pads in 23 patients. Figure 13.5 shows postoperative pressure recordings which confirm the effectiveness of such pads in distributing ischial pressures over a larger area.
Principles of foot and ankle orthoses
Maneesh Bhatia in Essentials of Foot and Ankle Surgery, 2021
AFOs are generally made from polypropylene due to their cost effectiveness and positive clinical outcomes. The thickness of the material is dictated by the size of the patient and the force being applied by the AFO, e.g., 4 mm polypropylene for a child or less active adult and 6 mm for an active adult. Disadvantages are that they can be bulky and difficultly to fit within footwear and, for this reason, the use of an AFO made from carbon fibre has become increasingly common practice. Carbon fibre can be expensive and generally there is little scope for adjustment of fit.
A power log-Dagum distribution: estimation and applications
Published in Journal of Applied Statistics, 2019
Hassan S. Bakouch, Muhammad Nauman Khan, Tassaddaq Hussain, Christophe Chesneau
The first data set represents the strength data originally reported in [3]. It represents the strength measured in GPa for single carbon fibers and impregnated 1000-carbon fiber tows. Carbon fiber tow is a bunch of carbon fibers, like a yarn, that are commonly woven into carbon fiber fabrics. Single fibers were tested under tension at a gauge length of 10 mm. Such data have been analyzed previously by Gupta and Kundu [11] and Asgharzadeh et al. [2]. The data are as follows: 1.901, 2.132, 2.203, 2.228, 2.257, 2.350, 2.361, 2.396, 2.397, 2.445, 2.454, 2.474, 2.518, 2.522, 2.525, 2.532, 2.575, 2.614, 2.616, 2.618, 2.624, 2.659, 2.675, 2.738, 2.740, 2.856, 2.917, 2.928, 2.937, 2.937, 2.977, 2.996, 3.030, 3.125, 3.139, 3.145, 3.220, 3.223, 3.235, 3.243, 3.264, 3.272, 3.294, 3.332, 3.346, 3.377, 3.408, 3.435, 3.493, 3.501, 3.537, 3.554, 3.562, 3.628, 3.852, 3.871, 3.886, 3.971, 4.024, 4.027, 4.225, 4.395, 5.020.
Generalized inverted Kumaraswamy generated family of distributions: theory and applications
Published in Journal of Applied Statistics, 2019
Farrukh Jamal, Muhammad Arslan Nasir, Gamze Ozel, M. Elgarhy, Naushad Mamode Khan
The data sets are obtained from Nichols and Padgett [23] and presented in Table 5. Suppose a process is producing carbon fibers to be used in constructing fibrous composite materials. Also, suppose it is desired that 99% of the fibers exceed a minimum tensile strength, i.e. the parameter of interest in this example is the first percentile of the tensile strength distribution. A decrease in the first percentile would indicate a decrease in tensile strength, and a control chart can be used to detect such changes. The Weibull distribution is a reasonable model for the tensile strength of such material. Carbon fibers of 50 mm in length were sampled from the process, tested, and their tensile strength observed. The upper control limit (UCL) and lower control limit (LCL) were computed from k subgroups of size n, assuming the process is stable. Data were simulated using a Weibull distribution with a shape parameter of 4.8 and a scale parameter of 3.2 (and thus, the first percentile 5 and 6.
Carcinogenic and health risk assessment of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene in the petrochemical industry using the US Environmental Protection Agency method
Published in International Journal of Occupational Safety and Ergonomics, 2022
Vahid Ahmadi-Moshiran, Ali Asghar Sajedian, Ahmad Soltanzadeh, Fatemeh Seifi, Rozhin Koobasi, Neda Nikbakht, Mohsen Sadeghi-Yarandi
Acrylonitrile is also one of the compounds used in the petrochemical industry. Acrylonitrile is a clear, colorless, highly flammable liquid with an unpleasant and irritating odor [4,21]. This material is used to produce carbon fibers based on poly-acrylonitrile for its widespread use in composite technology [22]. This compound is produced in the form of granules in the petrochemical industry. Acrylonitrile poisoning in humans causes eye and nose irritation, weakness, difficulty breathing, dizziness, impaired decision making, cyanosis, nausea and seizures. Acrylonitrile also causes severe skin burns. Chronic exposure to this compound has also been shown to damage normal liver and kidney function [23]. Preliminary epidemiological studies have shown a potential association between occupational exposure to acrylonitrile and respiratory cancer [24]. In 1999, the IARC reduced acrylonitrile carcinogenicity classification from potential human carcinogen (group 2A) to probable human carcinogen (group 2B) [25,26].
Related Knowledge Centers
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