We have developed a device that can easily measure the temporal imaging characteristics of CMOS/CCD cameras, such as the elapsed time of inter-frames, exposure time, and scanning speed of the rolling shutter. This device consists of two large 7-segment LEDs, 240 common LEDs, a one-chip PIC microcontroller, and other logic ICs. Three types of specialized printed circuit boards were also designed to facilitate device fabrication and improve the operational stability of the circuit. This paper provides a detailed technical explanation, including the circuit configuration and operating principles. Next, we conducted tests to confirm the specifications of the device through 8 hours of signal measurements using an oscilloscope, high-speed video camera recording, and shooting experiments with a global shutter camera and a rolling shutter camera. As a result, it was confirmed that this device operates according to our design specifications and that it is possible to measure the scanning speed of the rolling shutter, etc. Moreover, the effectiveness of this device was demonstrated by showing the results of measurement using various cameras.

　An electrostatic detection device (EDD) is a device that uses electrostatic charge to detect invisible indented writing impressions left on a paper surface. In this study, the following four types of experiments for the phenomena of the EDD detection and the possible applications other than detecting the indented writing impressions were conducted and discussed. First, the EDD detections were examined with various color materials on a paper: marker ink, whiteboard marker ink, vermillion inkpad ink, and inkjet printer ink. Second, visualization of the characters without indentations was attempted by EDD. Third, the EDD detections were examined with sweat, oils and fats. Fourth, visualization of obliterated and tampered characters or patterns of documents was attempted by EDD.

　The results showed that the adhesion of toner onto the Mylar film differed depending on the color material component: toner occasionally adhered tracing only the outline as well as the whole face of characters. This suggested that the chemical properties of the color material components affected the detection results. In addition, characters without indentations were visualized from the table top of EDD, which indicated the EDD can detect color materials and triboelectric charge caused by writing. This finding suggested that the phenomenon that the EDD detects fingerprint is due to its detection of sebum transferred to the paper. Furthermore, the EDD succeeded in visualizing obliterated and tampered characters or patterns on samples that could not be visualized by infrared inspection. Consequently, the EDD is considered to be applicable to other methods of detecting the indented writing impressions as a method for analyzing chemical property of color material components, fingerprint detection, visualization of static electricity traces without indentations and obliterated characters or patterns.

 Identification of ignitable liquid is essential in the investigation and trial of arson involving flammable liquids such as gasoline. If proper evidence collection is not accomplished, the results of subsequent fire debris analysis will be adversely affected. Although fire engineering knowledge of effective evidence collection points exists, chemical knowledge is rather lacking. Therefore, to pursue an efficient field detection method, this study examined (1) the increase in gas-phase inhalation when using detector tubes, (2) the sealing of samples, and (3) the validity of flooring materials as evidence collection points. As a result, we found that increasing the gas-phase inhalation of detector tubes is not recommended because it excessively increases false positives, that sealing samples in sampling bag is also effective for field detection, and that flooring materials can retain more ignitable liquid residues than surface fire debris. The flooring material retained the ignitable liquid with relatively little weathering, which, based on previous studies, would suggest that it could be retained for a long period of time. Furthermore, the locations where ignitable liquids were sprayed and detected showed considerable agreement, suggesting that flooring materials are suitable for a place to collect evidence.

　The stability of Δ⁹-tetrahydrocannabinol acetate (Δ⁹-THC-OAc) in the presence of diluents or during vaping was investigated. Laboratory-made pure Δ⁹-THC-OAc and glycerol, propylene glycol (PG), or polyethylene glycol 400 (PEG400) were dissolved in ethanol and subjected to the quantification method for Δ⁹-tetrahydrocannabinol (Δ⁹-THC) recommended by UNODC. The pure Δ⁹-THC-OAc diluted by glycerol, PG, or PEG400 was stored at 40°C for 27 days. A retail liquid product of Δ⁹-THC-OAc containing Δ⁹-THC as an impurity was stored at 80°C for 28 days in the presence of glycerol, PG, or PEG400. A cartridge containing the Δ⁹-THC-OAc liquid was installed in an e-cigarette device, which was heated and vaporized using a syringe connected to the cartridge through a silicone tube. The Δ⁹-THC-OAc liquid was put into a test tube and heated at 200 or 400°C for 5 min. The relative concentrations of cannabinoids in the test solution before and after each operation were measured by liquid chromatography with photodiode array detection or by gas chromatography with flame ionization detection. Δ⁹-THC was not detected in any cases of pure Δ⁹-THC-OAc, and it decreased or disappeared in all cases of Δ⁹-THC-OAc liquid. The present result showed that Δ⁹-THC-OAc does not decompose into Δ⁹-THC during each process.