Nondestructive Differentiation of Polyester Single White Fibers Using Synchrotron Radiation Microbeam X‐ray Fluorescence Spectrometry with Vertical Focusing

Design of a monocapillary with an inner Al2O3/HfO2 multilayer to obtain focused monochromatic hard X-rays

An X-ray monocapillary with an inner multilayer can be a promising optical device to obtain focused monochromatic X-rays. A focused beam is acquired via controlling the shape of the monocapillary meanwhile monochromatic X-rays are screened out by the inside multilayer. For hard X-rays such as C u-k α line 8.04 keV and M o-k α line 17.44 keV, A l 2 O 3/H f O 2 is an effective material pair for the X-ray multilayer that can reflect the X-rays at an acceptable efficiency. In this work, four tapered-monocapillaries with inner A l 2 O 3/H f O 2 multilayers are designed to focus and monochromatize X-rays (8.04 keV and17.44 keV, respectively) from the point source and collimated beam. The theoretical transmission performance, including the beam size, reflectivity, and monochromaticity of the device, is also calculated. The results show that the ideal optics can focus desired X-rays with efficiency of about 60%. It provides a reference for fabricating this optics in the future, especially via the atomic layer deposition (ALD) technique, which represents great potential to coat uniform film on a curved surface.

Non-destructive analysis of hollow-shaped single fibers using X-ray computed tomography

A commercial high-resolution X-ray computed tomography (CT) was utilized for non-destructive analysis of single fibers. The micro-CT apparatus was employed because it is applicable to both colored and colorless fibers. A sample preparation using adhesive sheets was demonstrated, and the method is similar to typical tape-lift sample collection method in crime cases. Different cross-sectional shapes of nylon and polyester single fibers were non-destructively distinguished, and the method is applicable to all types of fibers. Cross-sectional areas, aperture ratios, and volumes of individual fibers were directly and automatically measured using the open-source software. The observed parameters were within a coefficient of variation of 3%. In addition, a mass of a single fragment of a fiber can be estimated when the local density is given.

Analysis of Single Synthetic Fibers Using a Portable Total Reflection X-ray Fluorescence Spectrometer

In this study, single synthetic fibers obtained from several textile products were analyzed by a portable total reflection X-ray fluorescence spectrometer. Characteristic elements, which would originate from such materials as catalysts, delustering agents, and dyes used for manufacturing synthetic fibers, were detected from single synthetic fiber samples, and the difference in the types of characteristic elements among the single synthetic fiber samples was observed.

Feasibility Studies of X-Ray Computed Tomography for Forensic Examination of Single Fibers

Non-destructive observations of cross-sectional shapes of acrylic single fibers using X-ray computed tomography (CT) were performed. A commercial X-ray CT apparatus (Rigaku nano3DX) was employed because of its micrometer-scale spatial resolution and remarkable image contrast for soft matter. We assessed two types of sample support, a paraffin strip and a nylon string, for single fiber samples in terms of easy handling and sample recovery. Fixed individual single fibers were loaded into a narrow polyimide tube in both cases, and the tube ensured that the sample remained in the field of view during the CT measurements. In both cases, the cross-sectional shapes of individual single fibers could be distinguished, with a circular shape for one sample and a triangular shape for the other. However, the support using a nylon string was found to be more suitable for further analysis. The cross-sectional profile of the obtained tomographic image showed a clear difference between polyimide and nylon. The intensity ratio or the image contrast corresponded to that of the local densities. It was also found that the effect of the artifact appeared at around the boundaries of the objects, but the local density could still be utilized for examining individual single fibers.

Nondestructive Mineral Imaging of Chinese Chive Leaves Withered by Physiological Damage Using Microbeam Synchrotron Radiation X-Ray Fluorescence Analysis

A significant problem encountered in Chinese chives (Allium tuberosum) grown in greenhouses is the reduction in the yield and quality due to symptoms of withered leaf tips. Withered leaf tips of three Chinese chive cultivars were nondestructively analyzed by microbeam synchrotron radiation X-ray fluorescence (μ-SR-XRF) imaging. Dead, wilting, and healthy parts of the leaves exhibited significant variations in the mineral composition. The Ca/K X-ray intensity ratios were significantly increased with the degree of withering.

Nondestructive discrimination of red silk single fibers using total reflection X-ray fluorescence spectrometry and synchrotron radiation X-ray fluorescence spectrometry

In a strangulation case, when a necktie is used as a murder weapon, the dyed silk single fiber becomes an important evidence sample to solve the crime. Dyed silk single fibers contain elements, such as Cr and Co, which are obtained from dyeing using metal mordants. Currently, there are no nondestructive and sufficiently sensitive elementary analytical methods for the forensic analysis of single fibers. Therefore, in this study, eight commercially available red silk samples were collected and used for total reflection X-ray fluorescence (TXRF) and synchrotron radiation X-ray fluorescence (SR-XRF) spectrometry. Benchtop TXRF detected both S in the silk protein and Cl and Ca, which are elements absorbed from the environment by silkworms, but also Cr, which is a dyeing derivative for metal mordants. The presence of Cr and Zn, in addition to the Zn/Cr signal intensity ratios, was reported to be particularly useful identifiers. In SR-XRF, the presence of Cr, Co, Zn, and Br and the Zn/Cr signal intensity ratios were reported to be useful discriminating indicators. In this study, the nondestructive discrimination capabilities of TXRF and SR-XRF measurements for the samples were found to be 85.7% and 100%, respectively. Therefore, we propose a combination of TXRF and SR-XRF as a new nondestructive single fiber identification method for forensic science. Moreover, if partial destruction of a single fiber is allowed, the observation of the cross section and micro-Fourier-transform infrared spectroscopy measurements is useful for identifying red silk fibers.