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Tensile properties of novel carbon/glass hybrid thermoplastic composite rods

Kimiyoshi Naito, Hiroyuki Oguma
2017 Composite structures  
Novel carbon/glass hybrid thermoplastic composite rods consisting of unidirectional PAN-based carbon fiber (T700SC), braids of E-class glass fibers, and thermoplastic epoxy matrix have been developed. Three types of hybrid rods with differing carbon/glass ratios (24K1P, 24K2P, and 24K3P) were fabricated. The crosssectional morphologies of the hybrid rods were observed using a digital microscope. Volume fractions of carbon fiber, glass fiber, matrix, and void of the hybrid rods were estimated
more » ... ng a specific gravity measurement via ethanol immersion and a thermogravimetric analysis. The tensile properties and fracture behavior of the hybrid rods were investigated. For all hybrid rods, the stress applied to the specimen was nearly linearly proportional to the strain until failure, with a tensile modulus of 65 (24K1P), 87 (24K2P), and 91 GPa (24K3P) and tensile strengths of 1.42 (24K1P), 1.80 (24K2P), and 1.84 GPa (24K3P). The tensile modulus and strength increased with increasing carbon fiber volume fraction. The Weibull statistical distribution of tensile strength for the hybrid rods was examined. The Weibull modulus of the tensile strengths for the hybrid rods were 23.77 (24K1P), 27.29 (24K2P), and 32.50 (24K3P). The Weibull modulus increased with increasing tensile strength and decreasing void volume fraction of the hybrid rods.
doi:10.1016/j.compstruct.2016.11.042 fatcat:7q4xsqlarzf2zjb7uqylivwbna

The 30th Symposium on Fatigue

Hiroyuki OGUMA
2011 Journal of the Society of Materials Science Japan  
., Kita-ku, Sapporo, 060-8628 574, June 2011 22 10 28 30 30 2 1 1 48 8 4 7 4 6 5 4 4 5 12 7 1 5 30 The 30 th Symposium on Fatigue by Hiroyuki OGUMA 23 3 11 Received  ... 
doi:10.2472/jsms.60.574 fatcat:3f6kwb3o2fgg7b5nq3fxjk6m34

Efforts of Clinical Training Hospital
臨床研修病院の取り組み

Hiroyuki Funayama, Shin Oguma
2009 Nihon Naika Gakkai Zasshi  
doi:10.2169/naika.98.453 fatcat:73gacmllvnbnxeij7o4xaxfngm

Animal Detection Using Thermal Images and Its Required Observation Conditions

Yu Oishi, Hiroyuki Oguma, Ayako Tamura, Ryosuke Nakamura, Tsuneo Matsunaga
2018 Remote Sensing  
Information about changes in the population sizes of wild animals is extremely important for conservation and management. Wild animal populations have been estimated using statistical methods, but it is difficult to apply such methods to large areas. To address this problem, we have developed several support systems for the automated detection of wild animals in remote sensing images. In this study, we applied one of the developed algorithms, the computer-aided detection of moving wild animals
more » ... DWA) algorithm, to thermal remote sensing images. We also performed several analyses to confirm that the DWA algorithm is useful for thermal images and to clarify the optimal conditions for obtaining thermal images (during predawn hours and on overcast days). We developed a method based on the algorithm to extract moving wild animals from thermal remote sensing images. Then, accuracy was evaluated by applying the method to airborne thermal images in a wide area. We found that the producer's accuracy of the method was approximately 77.3% and the user's accuracy of the method was approximately 29.3%. This means that the proposed method can reduce the person-hours required to survey moving wild animals from large numbers of thermal remote sensing images. Furthermore, we confirmed the extracted sika deer candidates in a pair of images and found 24 moving objects that were not identified by visual inspection by an expert. Therefore, the proposed method can also reduce oversight when identifying moving wild animals. The detection accuracy is expected to increase by setting suitable observation conditions for surveying moving wild animals. Accordingly, we also discuss the required observation conditions. The discussions about the required observation conditions would be extremely useful for people monitoring animal population changes using thermal remote sensing images. species are threatened with extinction by hunting or human activities, such as land-use changes. Invasive alien species were introduced intentionally or unintentionally by humans from overseas or from other areas in the country. Overabundant species cause serious damage to agriculture and forestry and affect ecosystems by their considerable population increases and expanding distributions. These problems are not independent, but rather are connected [1]. In particular, conflict between wildlife and humans is a serious problem at the blurred boundary between species near urban areas in Japan. These imprecise boundaries are caused by abandoned farmlands and depopulation by hunters accompanying the rapidly decreasing and ageing rural population. 'Satoyama' is defined as a unique human-influenced natural environment that has been shaped and sustained over a long period by diverse human activity. Studies are needed to determine how to manage satoyama landscapes in such a way that the balance between the needs of humans and nature can be restored, particularly in regard to damage to forests and farmland caused by wild animals [2] . In particular, sika deer (Cervus nippon) have caused serious damage to the agricultural and forestry industries by tree bark-stripping and ecosystem changes. The amount of damage to agriculture by wild animals totaled about 166 million US dollars, and that by sika deer was about 57 million US dollars in 2014 (1 US dollar = 115 Japanese yen) [3] . To address these problems, the conservation and management of wild animals is necessary. The adaptive management of wild animals, a systematic approach for improving resource management by learning from management outcomes [4, 5], is essential. Adaptive management of wild animals consists of the prediction of increases and decreases, plans for hunting goals, abundance adjustment, and monitoring abundance using population indices to determine changes in the population size of wild animals. However, there is insufficient population information for sika deer, which are crepuscular animals with large habitat areas [6] . Although wild animal populations have been estimated using statistical methods, it is difficult to apply such methods to large areas because they require man power and are tremendously laborious. To resolve these issues, remote sensing is a promising method. However, even in open areas, it is difficult to identify animals in remote sensing images because the shapes of objects may differ markedly when viewed from above instead of from the side, as humans are accustomed to doing. Moreover, there is the potential for oversight because an enormous amount of data must be analyzed [7] . To address this issue, we have developed several support systems for the automated detection of wild animals in remote sensing images. These systems reduce the number of person-hours required to survey wild animals from large numbers of remote sensing images. One of these is the computer-aided detection of moving wild animals (DWA) algorithm [8] . The algorithm automatically extracts moving wild animals using the time difference between two overlapping visible images. The advantages of the algorithm are as follows. (i) Almost no detection errors occur, even in sparse forest areas: In forest areas, a tip of a tree appears in different positions when viewed from different points. Accordingly, simple differences between two images can cause detection errors. The DWA algorithm can be applied to sparse forests because relief displacement effects do not cause false detection; (ii) Applicable to large areas: The DWA algorithm does not require fixed cameras because it uses overlapping areas in photographs taken from a flying platform. Thus far, the use of the algorithm has been limited to the daytime because visible and near-infrared images have been used. However, many large mammals, such as sika deer, are crepuscular. For this reason, we used thermal images, in which animals can be identified in semi-dark conditions. Very few studies have used thermal remote sensing images to monitor wild animals [9] [10] [11] [12] . Furthermore, it is difficult to distinguish animals from trees in thermal images in some observation conditions [9, 10] because surface temperature contrast between detection targets and the background is essential to extract targets from thermal images. Therefore, existing studies of the application of thermal remote sensing images to monitor wild animals [11, 12] are limited to open, cool areas. Urban areas contain many hotspots, such as streetlights; thus, we attempted to use pairs of overlapping thermal images obtained at different times to automatically extract only moving animals.
doi:10.3390/rs10071050 fatcat:tgvht5wimbfzxofefnpigti3km

生態学者のための分光計測
Spectrometry for ecologists

Yutaka Okuzaki, Koji Mochida, Shin Nagai, Tatsuro Nakaji, Hiroyuki Oguma
2017 Nihon Seitai Gakkaishi  
Plos One, 9:e101497 Ide R, Oguma H (2010) Use of digital cameras for phenological observations.  ... 
doi:10.18960/seitai.67.1_41 fatcat:mhubh2ejozb4tcte4kj2ctp34a

Scale-dependent effects of windthrow disturbance on forest arthropod communities

Toshihide Hirao, Masashi Murakami, Jiro Iwamoto, Hino Takafumi, Hiroyuki Oguma
2007 Ecological research  
The effect of disturbance on local communities may operate via a spatial landscape context. We examined the scale-dependent effects of windthrow disturbance caused by a large typhoon on three arthropod communities in a temperate forest of Japan. Canopy arthropods were collected by beating foliage, forest-floor arthropods were collected by sweeping the vegetation, and flying arthropods were collected in Malaise traps. To assess the "functional spatial scale" at which arthropods responded to
more » ... fall disturbance, the gap rate was quantified at different spatial scales by sequentially enlarging the radius of a circular landscape sector by 10 m from 10 to 500 m. We then analyzed the responses of order richness and abundance to the gap rate for each arthropod community. The spatial scale of the significant best-fitting model, which was selected from the models fitted to the gap rate at stepwise spatial scales, was regarded as the arthropod-specific functional spatial scale. Arthropod order richness was not dependent on the gap rate. In contrast, arthropod order abundance depended significantly on the gap rate in many orders, but varied in the response direction and functional spatial scale. These order-specific, scale-dependent responses to tree-fall gaps would complicate interactions among organisms, leading to complex community organization. An understanding of the spatial processes that link the use of space by organisms with the spatial scale at which ecological processes are experienced is required to elucidate the responses of populations, communities, and biotic interactions to disturbances in a spatial landscape context.
doi:10.1007/s11284-007-0370-3 fatcat:kaeldtccqvh65o7x4mogwtateq

Tensile properties of novel carbon/glass hybrid thermoplastic composite rods under static and fatigue loading

Kimiyoshi Naito, Hiroyuki Oguma
2017 Matéria  
Novel carbon/glass hybrid thermoplastic composite rods have been developed consisting of a PAN-based carbon fiber, an E-glass fiber, and a thermoplastic matrix. Three types of hybrid rods with different carbon/glass ratios were then fabricated. The surface and cross-sectional morphologies of the hybrid rods were observed using a digital microscope. Additionally, the volume fractions of carbon/glass fibers, matrix, and void were determined by specific gravity measurements and thermogravimetric
more » ... alyzes. The glass fibers in the hybrid rods display a braided structure of the 2/2 twill weave. The braid angle (defined as the orientation angle of the interlacing yarns with respect to the longitudinal axis of the rod) ranged from 22.3° to 35.2°. The various volume fractions were in the ranges of 24.6-46.2% for the carbon fiber, 23.2-39.8% for the glass fiber, 23.4-25.5% for the matrix, and 7.3-10.2% for the voids. The tensile properties and fracture behavior of the hybrid rods under static and fatigue loading were also investigated. For the static tests, the stress applied to the specimen was nearly linearly proportional to the strain until the failure of all-hybrid rods. The tensile modulus, strength, and failure strain of the hybrid rods were measured in the ranges of 65-91GPa, 1.42-1.84 GPa, and 2.1-2.2%, respectively. The tensile modulus and strength increased as the volume fraction of the carbon fiber increased. However, the failure strain decreased as the volume fraction of the carbon fiber increased. For fatigue tests, the maximum applied stress-number of cycles to failure (S-N) curves for all-hybrid rods were obtained from 0.1 of the stress ratio (minimum/maximum stress) and 10 Hz of the loading frequency. The fatigue strength at 10 7 cycles for all-hybrid rods was less than 30% of ultimate breaking stress. The fatigue performance of the hybrid rods was significantly lower than that of conventional carbon fiber reinforced polymer matrix composites and steel rods. The voids in the hybrid rods affected the fatigue tensile properties.
doi:10.1590/s1517-707620170002.0176 fatcat:uolhr7uae5dknctxtgy6nld2zq

Applicability of Green-Red Vegetation Index for Remote Sensing of Vegetation Phenology

Takeshi Motohka, Kenlo Nishida Nasahara, Hiroyuki Oguma, Satoshi Tsuchida
2010 Remote Sensing  
Acknowledgements We thank Shin Nagai (Japan Agency for Marine-Earth Science and Technology); Hiroyuki Muraoka (Gifu University, Japan); Nobuko Saigusa and Reiko Ide (National Institute for Environmental  ... 
doi:10.3390/rs2102369 fatcat:mk2p2ne7jvc2hixt4pj5bs4s2a

The development of an optical scanner method for observation of plant root dynamics

Masako Dannoura, Yuji Kominami, Hiroyuki Oguma, Yoichi Kanazawa
2008 Plant Root  
Hiroyuki Oguma is a senior researcher in Center for Global Environmental Research, NIES with a interest in vegetation mapping by SAR data.  ... 
doi:10.3117/plantroot.2.14 fatcat:s52qhas2z5fnxi22aixbeksahi

A New Method of Acidity Measurement of the Acid Paper

Nobutaka YOSHIKUNI, Tetsuya ENDO, Hiroyuki MORITA, Koichi OGUMA, Shizuo FUJIWARA
1994 Joho Chishiki Gakkaishi  
doi:10.2964/jsik_kj00003381835 fatcat:hhoua6hiizcudbpuunpavv4jdm

Decline in the alpine landscape aesthetic value in a national park under climate change

Kota Mameno, Takahiro Kubo, Hiroyuki Oguma, Yukihiro Amagai, Yasushi Shoji
2022 Climatic Change  
AbstractAlpine landscapes are projected to be degraded under climate change, which would threaten their benefits to society. Previous studies, however, have been limited to aesthetic change, and it remains unclear how much the aesthetic change would affect human welfare. To address this issue and gain insights into climate change adaptation policies, we conducted a choice experiment survey using digitally manipulated images based on climate change scenarios and natural scientific knowledge in a
more » ... mountainous national park in Japan. We uncovered that park visitors appreciate the alpine landscapes that include snow patches on mountains and some types of alpine flowers by analyzing the data from 445 respondents. Conversely, both the invasion of alpine vegetation by dwarf bamboo and the disappearance of snow patches due to climate change substantially deteriorated the perceived aesthetic benefits from alpine landscapes. The economic loss caused by climate-induced landscape degradation was estimated at more than 100 USD per visitor, at maximum; the disappearance of snow patches and invasion by dwarf bamboo reduced the benefits by approximately 13 USD and 101 USD, respectively. Our findings suggest that sustaining the aesthetic value of alpine landscapes in national parks via climate change adaptation has potentially significant economic benefits. By supposing that the mountain national park attracts 70,000 visitors in summer, climate change would cause as a minimum of eight million USD economic loss at the park without appropriate measures annually. Our findings highlight the importance of climate change measures by considering climate change impacts on social benefits associated with alpine landscapes.
doi:10.1007/s10584-022-03322-1 fatcat:xxfwle56nzewfklstm6pwt7ape

SecSel, a new software tool for conservation prioritization that is applicable to ordinal-scale data for multiple biodiversity features [article]

Takenaka Akio, Oguma Hiroyuki, Amagai Yukihiro, Ishihama Fumiko
2021 bioRxiv   pre-print
AbstractSecSel, a protected-area prioritization tool, has been developed to help design areas that efficiently protect multiple features, including conservation of biodiversity and use of ecosystem services. The prioritization by SecSel is based on evaluation of the local units of each feature. The evaluation metrics should be quantitative but need not be ratio scale. The minimum requirement of the input data is that they are ordinal. The conservation target is the number of local units with
more » ... h values of each feature to be protected in the area. SecSel can handle conflicts among features, including conflicts between conservation and utilization of land or specific ecosystem functions. Before the selection procedure, one of a conflicting pair of features in a site is discarded. That decision is based on the dispensability of the local unit to fulfilling the conservation target of each feature. SecSel also considers the cost of including each site in the protected area and the compactness of the area in terms of total boundary length or the distance to the nearest site. To demonstrate the functionality of Secsel, we used it to design land use in an alpine region of northern Japan where conservation of alpine vegetation and its recreational use are important considerations.
doi:10.1101/2021.02.15.431247 fatcat:dw6dqed6qbcfdplhzqdyiupw7a

Vegetation Changes during the Last Decade at Mt. Komagatake

Ayako SHIMONO, Junko MAKINO, Akira MUROMURA, Hanako NAKAMURA, Natsuo SOBAZHIMA, Hiroyuki OGUMA
2019 Journal of Geography (Chigaku Zasshi)  
Oguma, H., Ide, R., Amagai, Y. and Hamada, T. (2019) : Using a time-lapse camera network to monitor alpine vegetation phenology and snowmelt times.  ... 
doi:10.5026/jgeography.128.105 fatcat:3d6t7cidmvctfloxtqgrkvo76e

Estimation of vegetation height in the Watarase wetland from digital aerial photographs

Tomomi TAKEDA, Hiroyuki OGUMA, Fumiko ISHIHAMA, Akio TAKENAKA
2010 Journal of Agricultural Meteorology  
Information on the ground surface can now be acquired easily and highly accurately using digital aerial photographs. A digital canopy model (DCM), which is calculated by subtracting a digital terrain model (DTM) from a digital surface model (DSM) of the vegetation, provides useful information for studies of wild animal habitats and plant species distributions. However, DCMs have been used mainly for forests, and their validity for herbaceous plants requires further verification. In this study,
more » ... e used the ADS40 airborne digital sensor to clarify the relationship between a DCM and the height of herbaceous species. Our study area was the Watarase wetland in the northern Kanto Plain, central Japan. Suitable habitats for the many rare plants found in this wetland are maintained by controlled burning in early spring. We acquired three DSMs: just after the controlled burn in April 2006; in August 2006, when the vegetation height peaked; and in April 2007, also just after the controlled burn. We calculated the DCM based on the difference between the August DSM and a DTM developed by using the minimum height values from the two April DSMs. We also performed a field survey during the August DSM acquisition, during which we measured the height of the uppermost leaves with a measuring pole at 16 measurement points and estimated the vegetation structure from photosynthetic photon flux density (PPFD) profiles measured with quantum sensors at each point. The calculated DCM height correlated very well to the height of the uppermost leaves (r 2 0.96), although it was about 100 cm lower. In contrast, the DCM and the height of maximum intercepted PPFD were highly correlated (r 2 0.97) and showed a 1 1 relationship.
doi:10.2480/agrmet.66.4.2 fatcat:qw72ld3qgzfyhkctku3u6zehg4

Comparison between Chlorination and UV Disinfection of Untreated Wastewater after Disasters

Kumiko OGUMA, Jatuwat SANGSANONT, Hiroyuki KATAYAMA
2014 Journal of Water and Environment Technology  
Chlorination and UV disinfection of untreated wastewater were compared, assuming that the activated sludge process is not functioning after disasters. Untreated wastewater samples were collected from a wastewater treatment plant that was severely damaged by the Great East Japan Earthquake in 2011, and the samples were subjected to chlorination or UV disinfection with or without preceding coagulation. Disinfection efficiency was evaluated based on the inactivation profiles of indigenous
more » ... nisms: total coliforms, Escherichia coli, and somatic phages. Chlorination without coagulation was not effective for either microorganism regardless of the chlorine injection rate (5 mg/L or 10 mg/L) and contact time (up to 30 min), but the inactivation efficiency was improved when coagulation preceded chlorination. Meanwhile, UV disinfection was effective even without coagulation, and the UV inactivation rate constant was not significantly different between samples with and without coagulation for either microorganism (ANOVA, p > 0.10) under the experimental conditions adopted in this study. In conclusion, the direct chlorination of untreated wastewater, as conducted after the Great East Japan Earthquake, is not very effective and we recommend coagulation before chlorination if secondary wastewater treatment is unavailable after a disaster. Alternatively, UV irradiation would be an option for disinfecting untreated wastewater after disasters.
doi:10.2965/jwet.2014.321 fatcat:yx3v6wzj2ffojps7o2p2mph3ea
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