Many building fires due to ignition of electrical wiring instruments have been reported. The ignition would be caused by electrical breakdown in insulation materials. The most common case of electrical breakdown is exothermic reaction. 150°C is caused due to the overload current and/or inferior electrical wire connection.
  The Polyvinyl Chloride (PVC) is widely used as an insulating material in various electric products. The exothermic phenomenon may cause deterioration of insulating properties in PVC due to the chemical decomposition. Many researches reported about the relationship between the fire hazard due to the degradation of insulating properties, for example, tracking index and insulation resistance value. However, the research in viewpoint of volume resistivity in high temperature region up to 200°C has not been reported, because PVC melts and/or deforms when the temperature rises.
  In this paper, conduction current has been measured while measuring thickness in the range from room temperature to 200°C under DC electric field in a heat-treated PVC sheet by using a developed high temperature space charge measurement system. It has been observed that the breakdown strength of the sheet strongly deteriorates in the range from room temperature to 90°C with 150°C-100 h (hour) heat-treated PVC, which is different from the results obtained with non-heat treated PVC and 100°C-300 h heat-treated PVC. The increase of conduction current is observed in the low temperature range before breakdown with 150°C-100 h heat-treated PVC. It shows that the heat treatment over 150°C deteriorates the breakdown properties in the range from room temperature to 90°C due to thermal decomposition and dehydrochlorination in PVC.

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  Although a number of methods based on spectrophotometry, gas chromatography (GC) and ion chromatography (IC) have been used for the analysis of inorganic toxic anions, gas chromatography/mass spectrometry (GC/MS) after derivatization is considered to be most reliable to determine such anions in biological samples due to its high selectivity.
  We here review the analytical methods to prove inorganic toxic anion poisoning using GC/MS. The causative substances of poisoning include hydrogen sulfide, polysulfides, cyanide, azide, nitrogen oxide, formalin, methanol, ethanol, methyl bromide and hydrofluoric acid.
  The key points for efficient derivatization of each anion and possibility of establishing simultaneous screening method for these anionic compounds are also discussed.

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  A criminal investigation laboratory is sometimes asked to identify chlorine bleach on damaged clothes of pedestrians in a criminal case. However, it is difficult to prove the detection of sodium hypochlorite, the main component of chlorine bleach, because it decomposes in a short time. In this study, decomposition of sodium hypochlorite was investigated to decide whether the ratio of chloride and chlorate ions produced through the decomposition of hypochlorite ion could be an effective indicator for the use of chlorine bleach. A sample was prepared by making a piece of filter paper or fabric absorbed with 25 µL of sodium hypochlorite solution or chlorine bleach and by drying it from one minute to 25 days. Chloride and chlorate ions in the sample were extracted into 100 mL of H₂O and determined by using ion chromatography. These two ions are stable and no significant change was observed in the ratio of them after the solution was dried. Therefore decomposed products can be detected from fabrics which had dried over a period of time and it is possible to show that chlorine bleach was used. The ratio of these ions exhibited separated ranges among bleach products by different manufacturers. In addition, the ratio of these ions was affected not only by the time after the bottle of bleach was opened but also the types of fabric material, even if bleach of same manufacturer was used. Comparing the ratio of two ions allows the discrimination of bleach products on the clothes, if two fabrics are made from the same material.

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  The scanned digital image was converted to three histograms of 256-bit depth for each color (red, green, blue) based on RGB color model, using image-processing software. Summation of three histograms at every depth was calculated. An inherent spectrum for each tape was featured. Thirty-one similar colored adhesive cloth tapes from 10 different manufacturers were examined. Cluster analysis was performed using 310 spectra obtained from 31 samples. Cluster analysis indicated that 31 samples were divided into 5 groups. Multiple correlation coefficient (R) was used to discriminate the adhesive cloth tapes. R was examined whether it would be possible to be considered a criterion of judgment of the difference discernment between samples to be shown as a numerical value. As a result, in order to judge it as the same adhesive cloth tape, it became clear that R was 0.994 or more.

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  The Concealed Information Test (CIT) assesses whether an examinee knows a crime-related item on the basis of response differences between crime-relevant and crime-irrelevant items. One of the effective measures in the CIT is respiratory speed. The respiratory speed has been defined as an average of moving distances of respiration curve in a specified time interval after the item onset. This moving distance differs between parts of a respiratory cycle. Therefore, the calculated respiratory speed is disproportionately affected by how the parts of the respiratory cycles are included in the time interval. To resolve this problem, Matsuda and Ogawa (2011) proposed a weighted average method. This method calculates the respiratory speed per cycle and weighs it with the proportion that the cycle occupies in the time interval. In the present study, we applied the weighted average method to the calculation of the inspiratory and expiratory speed. Using the weighted average method, the discrimination performance of the inspiratory/expiratory speed descriptively increased as compared with using the original method. However, as for the expiratory speed, statistical tests did not find significant differences between the original and weighted average method. These results raise the next issue: The detection method of respiratory cycles should be more sophisticated.

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  The current study compared two types of transducers of respiratory movements used for psychophysiological recordings, evaluating their performance in capturing and reproducing variations in underlying respiratory movements. We examined a newly developed air-filled bellows-type transducer and compared its performance against the carbon-film transducer, which is currently used in polygraph examinations for criminal investigations in Japan. An experiment using a calibrator to control underlying movements revealed that the performance of the air-filled bellows-type transducer was superior to that of the carbon film-type transducer in capturing the morphology of respiratory waveforms as well as variations in their amplitude. A polygraph experiment (n=19) demonstrated that the air-filled bellows-type transducer produced differences with larger effect sizes between critical and non-critical items in respiratory measures compared with the carbon-film type transducer. These results indicated that the air-filled type transducer exhibited superior performance for the recording of respiratory movements.

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[in Japanese]

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