Comparison of length and dynamics of wood pieces in streams covered with coniferous and broadleaf forests mapped using orthophotos acquired by an unmanned aerial vehicle

As wood pieces supplied by landslides and debris flows are one of the main components of ecological and geomorphic systems, the importance of quantifying the dimensions of the wood pieces is evident. However, the low accessibility of disturbed channels after debris flows generally impedes accurate and quick wood-piece investigations. Thus, remote-sensing measurements for wood pieces are necessitated. Focusing on sub-watersheds in coniferous and broadleaf forests in Japan (the CF and BF sites, respectively), we measured the lengths of wood pieces supplied by landslides (> 0.2 m length and > 0.03 m diameter) from orthophotos acquired using a small unmanned aerial vehicle (UAV). The measurement accuracy was analyzed by comparing the lengths derived from the UAV method with direct measurements. The landslides at the CF and BF sites were triggered by extremely heavy rainfalls in 2017 and 2018, respectively. UAV flights were operated during February and September 2019 at the CF site and during November 2018 and December 2019 at the BF site. Direct measurements of wood pieces were carried out on the date of the respective second flight date in each site. When both ends of a wood piece are satisfactorily extracted from an orthophoto acquired by the UAV, the wood-piece lengths at the CF site can be measured with an accuracy of approximately ±0.5 m. At the BF site, most of the extracted lengths were shorter than the directly measured lengths, probably because the complex structures of the root wad and tree crown reduced the visibility. Most wood pieces were discharged from landslide scars at the BF site, but at the CF site, approximately 750 wood pieces remained in the landslide scars approximately 19 months after the landslide occurrence. The number of wood pieces in the landslide scars of the CF site increased with increasing landslide area, suggesting that some wood pieces can be left even if large landslides occur. The lengths and locations of the entrapped wood pieces at both sites were not significantly changed between the two UAV flight dates. However, during this period, the rainfall intensities around the CF site measured by the closest rain-gauge of the Japan Meteorological Agency reached their second highest values from 1976 to 2019, which exceeded the 30-year return period. This suggests that most of the entrapped wood pieces rarely migrated even under intense rainfall.

Comparison of length and dynamics of wood pieces in streams covered with coniferous and broadleaf forests mapped using orthophotos acquired by an unmanned aerial vehicle

As wood pieces supplied by landslides and debris flows are one of the main components of ecological and geomorphic systems, the importance of quantifying the dimensions of the wood pieces is evident. However, the low accessibility of disturbed channels after landslides and debris flows generally impedes accurate and quick wood-piece investigations. Recent advances in photogrammetry techniques may overcome such issues. In this study, we used orthophotos acquired using a small unmanned aerial vehicle (UAV) to measure the lengths of wood pieces (> 0.2-m long and > 0.03-m diameter) entrapped mainly by check-dams. We focused on channels that are located in coniferous and broadleaf forests and affected by two different landslide events. The measurement accuracy was analyzed by comparing the lengths derived from the UAV method with direct measurements. When the both ends of a wood piece are satisfactorily extracted from an orthophoto acquired via the UAV, the wood-piece lengths of coniferous trees can be measured with an accuracy of approximately ±0.5 m. For broadleaf trees, most of the extracted lengths were shorter than the directly measured lengths, probably due to the low visibility arising from the complex structures of the root wad and tree crown. Most wood pieces were discharged from landslide scars in the broadleaf forest, whereas approximately 750 wood pieces were left in the landslide scars of the coniferous forest. The number of wood pieces in the landslide scars increased with the increase in the landslide area, suggesting that some wood pieces can be left even if large landslides occur. There were no significant changes in the lengths or locations of the entrapped wood pieces, at either site seven months after the first UAV flight. In the coniferous forests, the rainfall that triggered landslides in 2017 exceeded the 100-year return level, which was an abnormally intense rainfall. Although the 2019 rainfall event that occurred between UAV flights did not provide enough rainfall to trigger landslides, rainfall intensities with different durations reached the second-highest value from 1976 to 2019, exceeding the 30-year return period. This suggests that most of the entrapped wood pieces rarely migrate even under extreme rainfall.

Safety of Concentrated Bioshell Calcium Oxide Water Application for Surface and Skin Disinfections against Pathogenic Microbes

Immediately post-production, commercially available bioshell calcium oxide (BiSCaO) water is colorless, transparent, and strongly alkaline (pH 12.8), and is known to possess deodorizing properties and broad microbicidal activity. However, BiSCaO Water may represent a serious safety risk to the living body, given the strong alkalinity. This study aimed to investigate the safety of BiSCaO Water for use as an antiseptic/disinfectant despite concerns regarding its high alkalinity. The change over time in pH of BiSCaO Water was measured during air contact (stirring BiSCaO Water in ambient air). When sprayed on metal, plastic, wood piece, paper, and skin surfaces, the pH of BiSCaO Water decreased rapidly, providing a white powder coating upon drying. Scanning electron microscopy images, energy dispersive X-ray elemental mapping, and X-ray diffractograms showed that the dried powder residues of BiSCaO Water were composed primarily of calcium carbonate. These results suggested that BiSCaO Water is a potent reagent that may overcome the obstacles of being strongly alkaline, making this material appropriate for use in disinfection against pathogenic microbes.

Variability in Radiocarbon Dates in Middle Pleniglacial Wood from Kurtak (Central Siberia)

The chronology of long Upper Pleistocene loess sequences in Eurasia is based on combined pedostratigraphy and radiocarbon dating of high-quality charcoal. The accuracy of such a chronology depends on the reproducibility and precision of the 14C dates. However, certain dates may show discrepancies with regard to their chronostratigraphic context based on series of coherent dates. In order to evaluate the consistency and variation in the 14C dates obtained from small charcoal pieces, this question was tested on a set of spruce wood remains with well-preserved tree rings found in the Middle Pleniglacial loess-loam sequence of Kurtak (central Siberia). Tree-ring analysis of five fairly large wood pieces from three successive layers, dated to about 30.0, 30.8, and 32.2–32.5 ka BP previously, was done by continuous sampling of 90–150 rings on each wood piece. This enabled direct comparison of the succession of tree rings with the 14C dates. A total of 133 dates was obtained for the five wood pieces. The results show fluctuations in the 14C dates within a time range between 1000 and 2000 yr. Four possible causes for such variation will be discussed herein: (1) internal variability of the AMS dating method; (2) outliers; (3) variations in the 14C background; and (4) external factors such as past atmospheric 14C variations.

Determination of the diffusion of monovalent cations into wood under isothermal conditions based on LiCl impregnation of Norway spruce

The impregnation of wood pieces in the course of pulping can be divided into primary (advective mass transport) and secondary (diffusive mass transport) penetration. Little is known about the latter partly because of the difficulties in the determination of the relevant diffusivities for this system. In the present article, a precise experimental methodology has been developed to measure the concentration profiles of cations as a function of wood piece dimensions, impregnation time, temperature, and wood structure. The cation concentration can be measured at any position in the impregnated wood piece. The impregnation of Norway spruce wood samples with LiCl was investigated. The impregnated wood pieces were cut mechanically into cubes, which were cut in slices by means of a microtome, and the eluate of the 0.4-mm-thick slices in HNO3 was analyzed by flame atomic emission spectroscopy. The method gave reasonable results, and defects in the wood piece (microcracks) were detectable. The preliminary results presented here have to be verified with more replicates due to the heterogeneity of wood.

Endoscopic Removal of an Unusual Foreign Body in the Nasopharynx in a 3-Year-Old Child

ABSTRACT Objective Reporting a rare case of impacted foreign body (wood piece) in the nasopharynx in a 3-year-old female child of 6 cm size and its endoscopic removal. Case report A 3-year-old female child was brought by her parents with history of purulent right nasal discharge, nasal obstruction and fever for the past 3 months. Anterior rhinoscopic examination shows purulent right nasal discharge. Diagnostic endoscopy showed a foreign body in the nasopharynx. Under GA using nasal endoscope a foreign body was found to be wooden piece and the same was removed. The removed foreign bo dy was measu red and fou nd to be of 6 c m in size. Postoperative period was uneventful. Conclusion Foreign body of 6 cm size in the nasopharynx in a 3-year-old child has not been reported in ‘world medical literature’. This case has been reported due to its rarity, difficulty in diagnosis and removal. How to cite this article Krishnappa BD. Endoscopic Removal of an Unusual Foreign Body in the Nasopharynx in a 3-Year-Old Child. Int J Head Neck Surg 2013;4(3):140-141.

An Investigation of the Crack Tendency on Wood Surfaces After Different Machining Operations

Summary A hypothesis describing tip-crack generation during different machining operations on sapwood of pine surfaces and the differences between the pith side and bark side were investigated. The goal was to determine whether initial tip-cracks are generated already during the machining operation, before weathering. The evaluation of the results showed that about 10 % of the annual rings on the pith side and about 1% of the annual rings on the bark side have cracks after the machining operation. A theoretical analysis of an idealised model using the finite element method (FEM) has also been carried out to investigate the tendency for growth of short initial tip-cracks during a simulation of the compression of a wood piece in a conventional planing operation. The analysis seems to confirm that there is a greater risk for cracks on the pith side than on the bark side.