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Artykuły w czasopismach na temat "Debris morphology"
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Jones, Joshua W., Eugene Chiang, Gaspard Duchêne, Paul Kalas i Thomas M. Esposito. "Giant Impacts and Debris Disk Morphology". Astrophysical Journal 948, nr 2 (1.05.2023): 102. http://dx.doi.org/10.3847/1538-4357/acc466.
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Abstract Certain debris disks have nonaxisymmetric shapes in scattered light which are unexplained. The appearance of a disk depends on how its constituent Keplerian ellipses are arranged. The more the ellipses align apsidally, the more nonaxisymmetric the disk. Apsidal alignment is automatic for fragments released from a catastrophic collision between solid bodies. We synthesize scattered light images, and thermal emission images, of such giant impact debris. Depending on the viewing geometry, and if and how the initial apsidal alignment is perturbed, the remains of a giant impact can appear in scattered light as a one-sided or two-sided “fork,” a lopsided “needle,” or a set of “double wings.” The last shape is difficult to reproduce in other scenarios involving gravitational forcing or gas drag, which do not align orbits as well. We compare our images with observations and offer a scorecard assessing whether the scattered light asymmetries in HD 15115, HD 32297, HD 61005, HD 111520, HD 106906, β Pic, and AU Mic are best explained by giant impacts, gravitational perturbations, or sculpting by the interstellar medium.
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Tsunetaka, Haruka, Norifumi Hotta, Yuichi Sakai i Thad Wasklewicz. "Effect of debris-flow sediment grain-size distribution on fan morphology". Earth Surface Dynamics 10, nr 4 (1.08.2022): 775–96. http://dx.doi.org/10.5194/esurf-10-775-2022.
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Abstract. Knowledge of how debris flows result in the fan-shaped morphology around a channel outlet is crucial for mitigation of debris-flow-related disasters and investigation of previous sediment transport from the upper channel. Therefore, using a flume connected to a deposition area (inundation plane), this study conducted fan-morphology experiments to assess the effects of differences in grain-size distribution within debris flows on changes in fan morphology. Two types of debris-flow material, i.e., monogranular particles comprising monodispersed sediment particles and multigranular particles comprising polydispersed sediment particles, were used to generate monogranular and multigranular experimental debris flows, respectively. By adjusting the average grain size coincident between the monogranular and multigranular flows, we generated two types of debris flow with similar debris mixture hydrographs but different grain-size distributions in the flume. Although the flow depths were mostly similar between the monogranular and multigranular flows before the start of the debris-flow runout at the deposition area, the runout distances of the front of the multigranular flows were shorter than those of the monogranular flows. The difference in runout distance was responsible for the variations in the extent to and location in which the debris flows changed their direction of descent, resulting in the different shapes and morphologies of the fans in response to grain-size distribution. Although the direction of descent of the flows changed repeatedly, the extent of morphological symmetry of the debris-flow fans increased at a similar time during fan formation irrespective of the grain-size distribution. In contrast to this similarity in the rate of change in fan symmetry, the shift of the multigranular flow directions eventually increased the extent of asymmetry in fan morphology and expanded the scale of deviations in fan morphology between experimental test runs. Therefore, wide-ranging grain-size distributions within debris flows likely result in complex fan morphology with a high degree of asymmetry.
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Pan, Hua Li, Jiang Cheng Huang, Li Qin Wei i Guo Qiang Ou. "A Study on Scouring Laws Downstream of Debris Flow Sabo Dams". Applied Mechanics and Materials 170-173 (maj 2012): 2071–76. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.2071.
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Debris flow sabo dam is one of the most widely used debris flow control engineering. Its stability and safety operation is a key to controlling the effect of hazard prevention and avoiding secondary hazard. Because of the particularity of debris flow, it’s very hard to observe the process and morphology directly by field investigation. Although the scouring depth calculation method in hydraulic engineering provide an idea for debris flow sabo dam, but it can’t be used directly for the calculation of scouring depth downstream of debris flow sabo dams and foundation designation of the control engineering. This paper analyzed the influence factors of scouring laws downstream of debris flow sabo dams and the research status home and abroad. It suggests studying the scouring process and laws downstream of debris flow sabo dams by theoretical analysis, mechanical analysis and energy method combined with simulation experiments, establishing quantitative relationship between the scouring laws, limited depth, morphology, sediment transportation characteristics and the feature parameters of debris flow.
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Li, Yining, i Peilin Zhang. "An online de-noising method for oil ultrasonic wear debris signal: fuzzy morphology component analysis". Industrial Lubrication and Tribology 70, nr 6 (13.08.2018): 1012–19. http://dx.doi.org/10.1108/ilt-12-2016-0302.
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Purpose In real working condition, signal is highly disturbed and even drowned by noise, which extremely interferes in detecting results. Therefore, this paper aims to provide an effective de-noising method for the debris particle in lubricant so that the ultrasonic technique can be applied to the online debris particle detection. Design/methodology/approach For completing the online ultrasonic monitoring of oil wear debris, the research is made on some selected wear debris signals. It applies morphology component analysis (MCA) theory to de-noise signals. To overcome the potential weakness of MCA threshold process, it proposes fuzzy morphology component analysis (FMCA) by fuzzy threshold function. Findings According to simulated and experimental results, it eliminates most of the wear debris signal noises by using FMCA through the signal comparison. According to the comparison of simulation evaluation index, it has highest signal noise ratio, smallest root mean square error and largest similarity factor. Research limitations/implications The rapid movement of the debris particles, as well as the lubricant temperature, may influence the measuring signals. Researchers are encouraged to solve these problems further. Practical implications This paper includes implications for the improvement in the online debris detection and the development of the ultrasonic technique applied in online debris detection. Originality value This paper provides a promising way of applying the MCA theory to de-noise signals. To avoid the potential weakness of the MCA threshold process, it proposes FMCA through fuzzy threshold function. The FMCA method has great obvious advantage in de-noising wear debris signals. It lays the foundation for online ultrasonic monitoring of lubrication wear debris.
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Jang, J. W., i I. Iwasaki. "Size and morphology of grinding media wear debris". Mining, Metallurgy & Exploration 9, nr 3 (sierpień 1992): 158–60. http://dx.doi.org/10.1007/bf03402989.
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Baker, David M. H., i Lynn M. Carter. "Probing supraglacial debris on Mars 2: Crater morphology". Icarus 319 (luty 2019): 264–80. http://dx.doi.org/10.1016/j.icarus.2018.09.009.
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Williams, Paul Allen, i Ian C. Clarke. "Ceramic Wear Debris in Total Joint Replacements: Review of Debris Morphology and Biological Response". Key Engineering Materials 218-220 (listopad 2001): 591–94. http://dx.doi.org/10.4028/www.scientific.net/kem.218-220.591.
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Wang, Shi Bo, Shi Rong Ge, Hong Tao Liu i Xiao Long Huang. "Wear Behaviour and Wear Debris Characterization of UHMWPE on Alumina Ceramic, Stainless Steel, CoCrMo and Ti6Al4V Hip Prostheses in a Hip Joint Simulator". Journal of Biomimetics, Biomaterials and Tissue Engineering 7 (październik 2010): 7–25. http://dx.doi.org/10.4028/www.scientific.net/jbbte.7.7.
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Ultra-high molecular-weight polyethylene (UHMWPE) has been used in total hip replacement for the last three decades. Despite the advancements in prosthesis design, the wear of UHMWPE remains a serious clinical problem; the release of wear debris may induce osteolysis and implant loosening. Understanding of wear behavior and wear debris morphology of the polyethylene is essential to improve the reliability of hip joint implants. The investigation in this paper carried out wear simulation tests of UHMWPE on Al2O3, 316L stainless steel, CoCrMo alloy and Ti6Al4V alloy, respectively. The lubrication of plasma solution and bovine serum solution was presented in wear tests. The effect of motion and loading on the wear behavior and wear debris morphology, and the influence of femoral head material and assembly style were studied in order to obtain a better understanding of the morphology of ultra-high molecular weight polyethylene wear particles. It is shown that the wear of UHMWPE acetabular cups against metal femoral heads was significantly higher than that against ceramic heads. The presence of protein in lubricant increases the wear of UHMWPE acetabular cups on Al2O3 heads. The wear rates of UHMWPE in multi-directional motion are approximately 2.5 times of those in uni-directional motion. The size distribution range of the UHMWPE debris particles for all head materials varies from submicron particles up to several hundreds micron. The size distribution range of wear debris particles is not directly related to wear resistance of UHMWPE, but significantly influenced by wear mechanisms. The UHMWPE debris particles produced in hip wear simulation tests are classified as round debris, flake-like debris and stick debris, which are closely related to the primary mechanisms of abrasive wear, adhesive wear and fatigue wear.
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Nash, David B. "A general method for morphologic dating of hillslopes". Geology 33, nr 8 (1.08.2005): 693–95. http://dx.doi.org/10.1130/g21479ar.1.
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Abstract Morphologic dating of hillslopes is the determination of the age of a hillslope by its morphology. Current methods match the observed morphology with the morphology predicted by the diffusion-equation model for hillslope evolution. The morphologic dating method presented here requires no specific model for evolution, but is only applicable to transport-limited hillslopes on which the downslope debris flux is some scale- and time-independent function of slope angle. If these conditions are met, changes in morphology with scale (e.g., height) for a set of hillslopes of a fixed age are identical to changes in morphology with time for a hillslope of a fixed scale. This fact provides the basis for a simple, generally applicable method for morphologically dating such hillslopes with any initial morphology. This new dating method may be applied to a wide variety of vegetated hillslopes in temperate humid regions and is an improvement over previous morphologic dating methods that relied on the diffusion-equation model.
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He, Xiao Ying, Hong Kai Chen, Hong Mei Tang i Guang Ju Wen. "Formation Mechanism Study on Houchuangzi Slope Debris Flow". Advanced Materials Research 243-249 (maj 2011): 3082–86. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3082.
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Taken the Houchuangzi slope debris flow along Kunming- -Songming highway as instance, analyzed the mineral composition of provenance on the slope debris flow adopted the polycrystal X ray diffractometer, which was rich in hydrophilic clay mineralssuch as kaolinite and montmorillnite; analyzed the fornation mechanism of the HouChuangzi slope debris flow by the laboratory model test, compartmentalized the fornation process of the HouChuangzi slope debris flow in to five stages from the aspects of slope debris flow morphology and crack extension mechanism.The results provide certain reference value for further research of the formation mechanical mechanism.
Rozprawy doktorskie na temat "Debris morphology"
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Gardner, David John. "Hypervelocity impact morphology". Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294316.
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Wilson, Jessica. "The Efficacy and Design of Coastal Protection Using Large Woody Debris". Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41573.
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Those who frequent the coastline may be accustomed to seeing driftwood washed onshore, some of it having seemingly found a home there for many years, others having been freshly deposited during the last set of storms; However, if a passerby were to take a closer look at the driftwood on the coastline, they may notice that some of these logs – also known as Large Woody Debris (LWD) – are anchored in place, a practice which is generally used for the purpose of stabilizing the shoreline or reducing wave-induced flooding. Records of existing anchored LWD project sites date back to 1997 and anecdotal evidence suggests that the technique has been used since the mid-1900’s in coastal British Columbia (BC), Canada, and Washington State, USA. Now, with an increased demand for natural and nature-based solutions, the technique is again gaining popularity. Despite this, the design of anchored LWD has largely been based on anecdotal observations and experience, as well as a continuity of design practices from the river engineering field. To date, there is no known peer-reviewed literature on the design or efficacy of LWD protection systems in a coastal environment.
In 2019, the “Efficacy and Design of Coastal Protection using Large Woody Debris” research project was initiated to determine if LWD are effective at stabilizing the shoreline under wave action, if they are effective at reducing wave run-up, and if they are durable enough to meet engineering requirements for shore protection. In addition, the project aimed to determine the optimum configuration of LWD for design purposes. To meet these objectives, this study included the following work: (1) field studies of existing LWD installations, (2) experimental modeling of beach morphology with and without LWD structures, (3) experimental modeling of wave run-up with and without LWD structures, and (4) development of preliminary design guidance.
The first phase of the project included field investigations at 15 existing anchored LWD sites in coastal BC and Washington State. Site characteristics, design techniques, and durability indicators were examined and correlated to a new design life parameter: ‘Effective Life’. Six primary installation techniques were observed: Single, Multiple, Benched, Stacked, Matrix, and Groyne. Observed durability and/or performance issues included: missing LWD, erosion, arson, wood decay, and anchor corrosion/damage. The Effective Life of anchored LWD was found to be strongly correlated to the tidal range and the upper beach slope for all installation types, and the LWD placement elevation relative to the beach crest elevation for single, shore-parallel structures. The many noted durability issues and ineffectiveness as mitigating erosion indicates that existing design methods for anchored LWD have not generally been effective at providing coastal protection and meeting engineering design life requirements.
A comprehensive set of over 60 experimental tests were completed as part of the overall research program. Thirty-two (32) tests were analyzed as part of this study relating to the morphological response of a gravel beach with and without various LWD configurations. The tests were conducted within a wave flume at the National Research Council’s Ocean, Coastal and River Engineering Research Centre (NRC-OCRE), at a large scale (5:1) based on site characteristics and LWD design characteristics made during the previous field investigations. Tests were also conducted to assess experiment repeatability, sensitivity to test duration, sensitivity to wave height, wave period, and relative water level, influence of regular waves, and influence of log roughness. The position of the most seaward LWD (whether considering distance or elevation) was found to be strongly linked to morphological response. A theoretical relationship was developed between LWD elevation and sediment volume change. Configurations which included LWD placement below the still water level, such as the Benched configuration, were found to be most effective at stabilizing the beach profile.
As part of the experimental modeling program, 24 tests were also conducted for the purpose of estimating the effect of LWD design configuration on wave run-up. In total, six different beach and LWD configurations were tested under a base set of four regular wave conditions. The study findings indicated that anchored LWD may increase wave run-up relative to a gravel beach with no structures. In particular, configurations with more logs tended to result in higher wave run-up. However, additional research is needed on the effect of LWD on wave run-up to confirm and expand these findings.
There are a number of potential engineering, ecological, social, and economic benefits associated with anchored LWD installations if designed, installed, and monitored appropriately for the site conditions and user needs. To realize these potential benefits, significant additional research is needed on the topic. One of the most significant barriers to usage is a lack of information on how to effectively anchor LWD structures. However, this research project provides a baseline for future comprehensive studies on the effect and design of coastal protection using LWD. The project provides preliminary design considerations for the usage of LWD as coastal protection and contributes to the growing body of literature on nature-based solutions.
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Penserini, Brian. "Debris Flow Network Morphology and a New Erosion Rate Proxy for Steepland Basins with Application to the Oregon Coast Range and Cascadia Subduction Zone". Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/19276.
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Reaches dominated by debris flow scour and incision tend to greatly influence landscape form in steepland basins. Debris flow networks, despite their ubiquity, have not been exploited to develop erosion rate proxies. To bridge this gap, I applied a proposed empirical function that describes the variation of valley slope with drainage area in fluvial and debris flow reaches of steepland channel networks in the Oregon Coast Range. I calibrated a relationship between profile concavity and erosion rate to map spatial patterns of long-term uplift rates assuming steady state. I also estimated the magnitude and inland extent of coseismic subsidence in my study area. My estimates agree with field measurements in the same area along the Cascadia margin, indicating that debris flow valley profiles can be used to make interpretations from spatial patterns of rock uplift that may better constrain physical models of crustal deformation.
This thesis includes unpublished co-authored material.
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Illgner, Peter Mark. "The morphology and sedimentology of two unconsolidated quaternary debris slope deposits in the Alexandria district, Cape Province". Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1005519.
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Research on hillslope surface processes and hillslope stratigraphy has been neglected in southern Africa. The amount of published literature on hillslope stratigraphy in southern Africa is very limited. Hillslope sediments provide a record of past environmental conditions and may be especially useful in calculating the recurrence interval of extreme environmental conditions such as earthquakes and intense rainfall events. The characteristics of hillslope sediments provide information as to their origin, transport and mechanisms of deposition. No published work could be found that had been undertaken on hillslope surface processes or stratigraphy in the eastern Cape coastal region. This study attempted to fill this gap in the geomorphic literature for southern Africa. The surface processes acting on hillslopes at Burchleigh and Spring Grove in the Alexandria district of the eastern Cape were examined in terms of slope morphology, surface sediment characteristics and the internal geometry of the hillslope sedimentary deposits. The late Quaternary hillslope sedimentary deposits at the two study sites are composed of fine grained colluvial sediments intercalated with highly lenticular diamicts. The fine grained colluvial sediments were emplaced by overland flow processes while the diamicts were deposited by debris flows. The sedimentary sequences at both study sites have a basal conglomerate interpreted as a channel lag deposit. Most slope failures preceding debris flow events were probably triggered by intense or extended periods of rainfall associated with cold fronts or cut-of flows. Seismic events may also have triggered slope failure, with or without the hillslope sediments being saturated. The results of this study indicate that a continuum exists between the slopewash dominated processes of the presently summer rainfall regions of Natal to the present winter rainfall regions of the western Cape where mass movement processes are significant. Hillslope deposits, therefore, provide a record of environmental conditions which may greatly facilitate proper management of the landscape.
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Diefenderfer, Heida Lin. "Channel morphology and restoration of Sitka spruce (Picea stichensis) tidal forested wetlands, Columbia River, U.S.A. /". Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5565.
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Gartner, Joseph E. "Relations between wildfire related debris-flow volumes and basin morphology, burn severity, material properties and triggering storm rainfall". Diss., Connect to online resource, 2005. http://wwwlib.umi.com/cr/colorado/fullcit?p1430198.
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Clark, Chase. "THE IMPACTS OF LOGGING WITH CURRENT AND MODIFIED BEST MANAGEMENT PRACTICES ON WATERSHED CHARACTERISTICS IN EASTERN KENTUCKY". UKnowledge, 2015. http://uknowledge.uky.edu/forestry_etds/25.
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In Kentucky, Best Management Practices (BMPs) were developed to protect the integrity of water resources during and after silvicultural operations, but their effectiveness is largely unknown. The study objectives were to (1) quantify the extent to which current BMPs minimized logging-related changes in stream water quality, channel morphology, and the content of woody debris and (2) quantify the extent to which modified BMPs influenced these characteristics. Six watersheds in eastern Kentucky were commercially logged in 2008-2009. In each watershed, one of three treatments was implemented (each replicated once). Treatment 1 (BMP) was based on current Kentucky BMPs. In treatments 2 (BMP+) and 3 (BMP++), current BMPs were modified with additional protective measures. Before the harvest, sampling sites were established in each watershed. Channel morphology and woody debris data were collected at each site in 2006 and again 2014. Data for water chemistry were retrieved from ongoing sampling records. BMP watersheds were compared to one another and to unharvested control watersheds in each year independently. Data within each individual watershed were also compared across years. The results indicate that current BMPs were effective in minimizing changes in the watershed characteristics examined here, and the benefits of modified BMPs were highly variable.
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Pecorari, Eliana. "Il materiale legnoso in corsi d'acqua a canali intrecciati: volumi, mobilità , degradazione ed influenza morfologica". Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425189.
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Natural wood in rivers has received wider attention in the scientific community only over the past two decades from different perspectives (biological, geomorphological and engineering). Wood has been studied mostly in mountain basins whereas large rivers have been less investigated.
The present research deals with different aspects related to in-channel wood in gravel bed rivers, including physical wood characteristics, wood storage and transport, and link between wood abundance and river morphology.
The analysis of physical characteristics of wood was carried out in three rivers: the Piave River (Veneto, Italy), the Magra River (Toscana, Italy) and the Ain River (Rhône- Alpe, France). Different variables were compared for a specific species (Populus nigra). Mean wood density range from 0.25 to 0.35 g/cm3, with Ain’s values differing significantly from the other rivers. The age of sampled wood elements is similar in the Piave and in the Magra (16 and 17 yr, respectively), whereas Ain’s samples are much older (31 yr). The growth coefficient si instead similar for the three rivers, but resistance to penetration is significantly higher in the Piave and presents a positive correlation with sample’s age.
As to wood transport, 10 logs were tagged with metal tags and radiofrequency transmitters to monitor their mobility. Unfortunately, the 2005 fall season was very dry and no significant events occurred, also the 2006 spring snowmelt runoff did not reach a sufficient stage to mobilize the tagged logs. In September 2006, the largest event of the year (below bankfull stage) did not reach the logs, but the bar erosion taking place near one tagged log caused its recruitment into the flow and its transport downstream. Transport distance was about 4 km, i.e. about 18 times the mean channel width.
The wood storage survey has regarded a 30 km reach in the Piave river between Ponte nelle Alpi and Busche (Belluno). Here the rivers features braided and wandering morphologies. Two integrated methods were implemented: field measurements in selected plots and interpretation of high-resolution (10 cm pixel) aerial photos at the reach scale.. Errors associated to wood measurements by using aerial photographs were evaluated the field plots. Results are encouraging, showing a good potential and efficiency of such approach for rivers where a total field survey would be unfeasible (ED < 50% per D < 15 cm; 40 < ED < 50% per 15 cm < D < 20 cm; ED < 10% per D > 20 cm).
The analysis based on aerial photos led to estimate average wood load to be within the range 3.7 – 9.1 m3/ha, depending on how wood jam volume is computed. Single wood elements present a mean diameter of 28 cm and a mean length of 7.5 m. Tree species indicate most of the wood derives from the riparian corridor but other species are also present due to lateral erosion of recent low terraces.
The analysis of wood storage at different reaches showed that wood is more abundant in braided channel more than in wandering reaches. Wood is mostly located on bars (rather equally in high and low ones), but a considerable fraction of wood is associated to islands in the wider braided reaches. A strong negative correlation is present between single wood elements’ volume and relative area occupied by low flow channels, whereas wood jam volume is strongly correlated with the relative area of islands.
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Binda, Andrey Luis. "A influência de detritos lenhosos na morfologia e na sedimentologia de leito no rio Guabiroba, Guarapuava - Pr". Universidade Estadual do Oeste do Parana, 2009. http://tede.unioeste.br:8080/tede/handle/tede/86.
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Trees, twigs and leaves fallen inside of the channel, form a significant component of the fluvial environment and natural occurrence in fluvial systems that cut forested areas. All these vegetal materials that are found inside of the channel are called wood debris. The wood debris play a key function in the ecology and geomorphology of channels, being able to affect the processes of the channels in an ample reach: since the hydraulic roughness, retention and sized grain of bed sediments, until the creation of steps and pools, being able to the times to control the standard of the channel and distance and/variation of fluvial features that are basic for the formation of aquatic habitat. In this context, the present research had as objective, to verify the influence of accumulations of wood debris on the morphology and sedimentology of stream bed in the river Guabiroba, Guarapuava, Center-South of the Paraná. The used techniques had included: installation of permanent transversal profiles (to the upstream and downstream of the accumulations) and sections of batimetric measurement, survey of the longitudinal profile and grain sized characterization of bed sediments. The measurement was carried throughout 15 months (December of 2007 the March of 2009) in four sections located in the main course of the river. The rainfall during the measurement allowed to particularizing the occurrence of only one period with rains above average (3 - 4ª Campaign). The results indicate the occurrence of sedimentation in the second and fifth measurement and processes of erosion in the third and fourth measurement. These processes erosive-depositional can in part be attributed to the pluviometric regime, with the periods of high entailed concentration of rains to the erosion of the stream bed and periods of related scarce and not concentrated rains with the deposition of sediments. The analysis of the data allows to establish some consideration: 1) predominance of processes of erosion in the sections of batimetric measurement; 2) bigger rate deposition in downstream cross-sectional profiles of the accumulations; 3) predominance of coarser sediments (gravel medium - sand very coarse) to upstream and finer sediments (gravel fine - sand medium) to downstream; 4) bigger diversity of depths in the immediacy of the accumulations; 5) establishment of riffles by the forced deposition of sediments and pools for the scour of the stream bed.
Árvores, galhos e folhas caídos dentro do canal formam um significativo componente do ambiente fluvial e de ocorrência natural em sistemas fluviais que cortam áreas florestadas. Toda essa carga de material de origem vegetal que se encontra dentro do canal é chamada de detritos lenhosos. Os detritos lenhosos desempenham função chave na ecologia e geomorfologia de canais, podendo afetar os processos do canal em um amplo alcance: desde a rugosidade hidráulica, retenção e grânulometria dos sedimentos de leito, até a criação de degraus e depressões, podendo, às vezes, controlar o padrão do canal e a distância/variação de feições fluviais que são fundamentais para a formação de habitat aquáticos. Num contexto desses, a presente pesquisa teve como objetivo verificar a influência de acumulações de detritos lenhosos sobre a morfologia e a sedimentologia de leito no Rio Guabiroba, município de Guarapuava, mesorregião Centro-Sul do Paraná. As técnicas utilizadas incluíram: instalação de perfis transversais permanentes (a montante e a jusante das acumulações) e seções de monitoramento batimétrico, levantamento do perfil longitudinal e caracterização grânulométrica de sedimentos do fundo. O monitoramento foi realizado ao longo de 15 meses (dezembro de 2007 a março de 2009) em quatro pontos localizados em dois trechos no curso principal do rio. A pluviosidade durante o monitoramento permitiu individualizar a ocorrência de apenas um período com chuvas acima da média (3ª a 4ª campanha). Os resultados indicam a ocorrência de sedimentação na segunda e quinta campanhas e processos de erosão na terceira e quarta campanhas. Esses processos erosivo-deposicionais podem, em parte, ser atribuídos ao regime pluviométrico, com os períodos de alta concentração de chuvas vinculados à erosão do leito e períodos de chuvas escassas e não concentradas relacionados com a deposição de sedimentos. A análise dos dados permite estabelecer algumas considerações: 1) predominância de processos de erosão nas seções de monitoramento batimétrico (Blocos 3D); 2) maior taxa de deposição nos perfis transversais situados a jusante das acumulações; 3) predomínio de sedimentos mais grossos (seixo médio - areia muito grossa) a montante da acumulação do que a jusante (seixo fino - areia média); 4) maior diversidade de profundidades nas imediações das acumulações; 5) estabelecimento de soleiras pela deposição forçada de sedimentos e depressões pela escavação do leito.
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Koulinski, Vincent. "Etude de la formation d'un lit torrentiel par confrontation d'essais sur modèle réduit et d'observations de terrain". Grenoble 1, 1993. http://www.theses.fr/1993GRE10211.
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L'etude locale du charriage torrentiel sur modele reduit de tres faible taille a montre que deux phenomenes nettement distincts cohabitent. D'une part, le charriage hyperconcentre correspond a un controle du transport solide et du lit par les conditions hydrauliques, le debit solide est tres importants et les grains sont d'autant plus facilement transportes qu'ils ont gros. D'autre part, lors du charriage ordinaire, la fourniture de materiaux par le lit est preponderante, les elements fins sont les plus mobiles et le debit solide varie dans des proportions importantes pour des conditions hydrauliques identiques. Il y a basculement irreversible d'un phenomene a l'autre. L'utilisation d'un modele de grande taille a montre que cette dualite se traduit par une heterogeneite spatiale des phenomenes, le tri granulometrique favorisant le deplacement des elements de taille moyenne. La confrontation de ces resultats a des observations de terrain a degage des regles de fonctionnement des torrents reels et a permis d'affiner la lecture morphologique et les mesures granulometriques du lit, facilitant alors considerablement l'approche des phenomenes torrentiels dans le cadre des etudes de cas
Książki na temat "Debris morphology"
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Hogan, Daniel Lewis. Channel morphology of unlogged, logged, and debris torrented streams in the Queen Charlotte Islands. Victoria, B.C: Ministry of Forests and Lands, 1987.
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Robison, E. George. Large woody debris and channel morphology of undisturbed streams in southeast Alaska. 1987.
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Cordova, Jerry J. Streamside forests, channel constraint, large woody debris characteristics, and pool morphology in low order streams, Blue Mountains, Oregon. 1995.
Znajdź pełny tekst źródłaCzęści książek na temat "Debris morphology"
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Nygård, A., H. P. Sejrup i H. Haflidason. "Morphology of Glacigenic Debris Flows on the Upper North Sea Fan". W European Margin Sediment Dynamics, 87–91. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55846-7_13.
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Hale, Robert C., Meredith E. Seeley, Ashley E. King i Lehuan H. Yu. "Analytical Chemistry of Plastic Debris: Sampling, Methods, and Instrumentation". W Microplastic in the Environment: Pattern and Process, 17–67. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-78627-4_2.
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AbstractApproaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include tire wear, paint chips, semisynthetics (e.g., rayon), and bioplastics. Plastics commonly contain chemical additives and fillers, which may alter their toxicological potency, behavior (e.g., buoyancy), or detector response (e.g., yield fluorescence) during analysis. Field sampling methods often focus on >20 μm and even >300 μm sized particles and will thus not capture smaller microplastics (which may be most abundant and bioavailable). Analysis of a limited subgroup (selected polymer types, particle sizes, or shapes) of microplastics, while often operationally necessary, can result in an underestimation of actual sample content. These shortcomings complicate calls for toxicological studies of microplastics to be based on “environmentally relevant concentrations.” Sample matrices of interest include water (including wastewater, ice, snow), sediment (soil, dust, wastewater sludge), air, and biota. Properties of the environment, and of the particles themselves, may concentrate plastic debris in select zones (e.g., gyres, shorelines, polar ice, wastewater sludge). Sampling designs should consider such patchy distributions. Episodic releases due to weather and anthropogenic discharges should also be considered. While water grab samples and sieving are commonplace, novel techniques for microplastic isolation, such as continuous flow centrifugation, show promise. The abundance of nonplastic particulates (e.g., clay, detritus, biological material) in samples interferes with microplastic detection and characterization. Their removal is typically accomplished using a combination of gravity separation and oxidative digestion (including strong bases, peroxide, enzymes); unfortunately, aggressive treatments may damage more labile plastics. Microscope-based infrared or Raman detection is often applied to provide polymer chemistry and morphological data for individual microplastic particles. However, the sheer number of particles in many samples presents logistical hurdles. In response, instruments have been developed that employ detector arrays and rapid scanning lasers. The addition of dyes to stain particulates may facilitate spectroscopic detection of some polymer types. Most researchers provide microplastic data in the form of the abundances of polymer types within particle size, polymer, and morphology classes. Polymer mass data in samples remain rare but are essential to elucidating fate. Rather than characterizing individual particles in samples, solvent extraction (following initial sample prep, such as sediment size class sorting), combined with techniques such as thermoanalysis (e.g., pyrolysis), has been used to generate microplastic mass data. However, this may obviate the acquisition of individual particle morphology and compositional information. Alternatively, some techniques (e.g., electron and atomic force microscopy and matrix-assisted laser desorption mass spectrometry) are adept at providing highly detailed data on the size, morphology, composition, and surface chemistry of select particles. Ultimately, the analyst must select the approach best suited for their study goals. Robust quality control elements are also critical to evaluate the accuracy and precision of the sampling and analysis techniques. Further, improved efforts are required to assess and control possible sample contamination due to the ubiquitous distribution of microplastics, especially in indoor environments where samples are processed.
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Li, Shuai, Xiaoqing Chen, Gongdan Zhou, Dongri Song i Jiangang Chen. "Influence of Bulk Density and Slope on Debris Flows Deposit Morphology: Physical Modelling". W Springer Series in Geomechanics and Geoengineering, 1495–99. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-97115-5_131.
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Fichera, Antonio, Laura Maria Stancanelli, Stefano Lanzoni i Enrico Foti. "Stony Debris Flow Debouching in a River Reach: Energy Dissipative Mechanisms and Deposit Morphology". W Advancing Culture of Living with Landslides, 377–83. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-53485-5_44.
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Samyn, Pieter, Alessandro Ledda, Jan Quintelier, Isabel Van Driessche, Gustaaf Schoukens, Patrick De Baets i Wim De Waele. "A Combination of Mathematical Morphology and Thermal Analysis of Wear Debris Explaining Polymer Sliding Mechanisms". W Materials Science Forum, 2237–40. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-462-6.2237.
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Nygård, A., H. Haflidason i H. P. Sejrup. "Morphology of a Non-glacigenic Debris Flow Lobe in the Helland Hansen Area Investigated with 3D Seismic Data". W European Margin Sediment Dynamics, 63–65. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55846-7_8.
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"Optimization Design of Process Parameters for Different Workpiece Materials in NMQL Grinding With Different Vegetable Oils". W Enhanced Heat Transfer Mechanism of Nanofluid MQL Cooling Grinding, 337–57. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1546-4.ch015.
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This research shows with superior lubricating, heat-conducting properties, and proper market price, Al2O3 and MoS2 nanoparticles have broad application prospects as lubricant additives. This work has been researched, and most researches are restricted to using one kind of lubricants to machine specific workpiece or multiple workpieces. There has been no systematic and detailed analysis of grinding performances from cutting mechanisms and debris formation mechanisms of different workpieces. Therefore, analysis of signal to noise ratio(S/N), variance, microstructure, and morphology analysis were used to study the influence of different typical nanofluid lubricants on the grinding performance of different materials in this chapter. Results showed that the optimal grinding parameters are using nodular cast iron and MoS2 nanofluid. Compared with other lubricants, MoS2 nanofluid can exert a significant effect on reducing wear of grinding wheel. In order to reduce surface roughness, MQL lubricating oils of the following sequence can be used: Al2O3 nanofluid, MoS2 nanofluid, and pure palm oil.
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Ruiz-Andrés, M., A. Conde, J. de Damborenea i I. García. "Wear Behavior of Aluminum Alloys at Slow Sliding Speeds". W Encyclopedia of Aluminum and Its Alloys. Boca Raton: CRC Press, 2019. http://dx.doi.org/10.1201/9781351045636-140000449.
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The investigated slow sliding speeds presented in this work enable the understanding of the wear behavior on aluminum alloys and could possibly facilitate the completion of the previously proposed wear mechanism map for aluminum at this slow sliding speed range. Dry sliding block-on-ring wear tests were carried out on aluminum alloys, AA5754 (Al-Mg), AA6082 (Al-Mg-Si), and AA7075 (Al-Zn-Cu), at a very slow sliding speed range (<0.01 m/s). A bearing steel ring of AISI 52100 was used as the counterbody. Tests were performed at varying contact pressures, 20, 100, and 140 MPa, and sliding speeds ranging from 0.001 to 1.5 m/s. The wear tracks and debris collected were examined by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD), with the aim of analyzing their morphology and composition. At relatively slow sliding speeds (>0.01 m/s), the specimens exhibited a wear process placed at the mild wear regime, characterized by oxidation and delamination mechanisms of both the aluminum specimen and the steel ring. However, at very slow speed range (<0.01 m/s), an increase in the wear rate and the friction coefficient is observed for all of the aluminum alloys, thus suggesting that an alternative wear mechanism could be taking place.
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Zhang, Xuecai, Na Li i Tao Chen. "Study on Petroleum Reservoirs Controlled by Sedimentary Facies in Chepaizi Area". W Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220382.
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The purpose of this paper is to clarify the paleocurrent direction and sedimentary characteristics of Cretaceous Qingshuihe formation (K1q) in Chepaizi area. Based on the analysis results of structural maturity and compositional maturity, this paper makes a more detailed exploration on the sedimentary environment and the source of clastic materials in the sedimentary period of K1q. Based on the seismic and drilling data, the paleocurrent direction is analyzed by using paleogeo-morphology and seismic reflection structure. The analysis of rock slices of core samples shows that the content of rock debris and feldspar in sandstone reservoir in the study area is high, the content of quartz is low, the weathering degree of samples is deep, the particle sorting is medium to good, the roundness is subround to subangular, the cementation type is pore cementation, and the structural maturity of sandstone is medium to low. The results of particle size analysis demonstrate that the suspension transportation of fine particles is the main transportation mode in the study area, and the rolling transportation is less. The paleogeomorphology shows that the terrain of the study area is high in the north and low in the south. The seismic profile indicates that low angle imbricate progradation reflection is developed in the northwest and northeast. On the basis of results, the following conclusions are obtained: the paleocurrent of K1q in Chepaizi area carried the northwest provenance into the northeast and south, experienced medium and long-distance transportation.
Streszczenia konferencji na temat "Debris morphology"
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Li, Kezhao, Qin Zhang, Zengzhang Guo, Jiangping Yuan, Chaoying Zhao i Keke Xu. "Space Debris Detection Algorithm Based on Mathematical Morphology". W 2009 International Conference on Artificial Intelligence and Computational Intelligence. IEEE, 2009. http://dx.doi.org/10.1109/aici.2009.350.
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Zhang Jian-rong, Yan-ying Guo i Guo-qing Yang. "Airport runway debris detection based on weighted fuzzy morphology algorithm". W 2010 International Conference on Computer Application and System Modeling (ICCASM 2010). IEEE, 2010. http://dx.doi.org/10.1109/iccasm.2010.5619089.
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Pagliara, Simone, i Michele Palermo. "Effects of Bridge Pier Location and Debris Accumulation on Equilibrium Morphology". W World Environmental and Water Resources Congress 2020. Reston, VA: American Society of Civil Engineers, 2020. http://dx.doi.org/10.1061/9780784482971.008.
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Leung, Vivian, i David R. Montgomery. "THE EFFECTS OF WOOD DEBRIS ON STREAMBED MORPHOLOGY: SPATIAL PATTERNS OF FLUID FLOW AND SEDIMENT TRANSPORT AROUND INDIVIDUAL PIECES OF WOOD DEBRIS". W GSA Connects 2022 meeting in Denver, Colorado. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022am-383919.
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Fitriadin, Ahmad Azmi, Jaza’ul Ikhsan i Puji Harsanto. "Morphology analysis in middle-downstream area of Progo River due to the debris flow". W GREEN PROCESS, MATERIAL, AND ENERGY: A SUSTAINABLE SOLUTION FOR CLIMATE CHANGE: Proceedings of the 3rd International Conference on Engineering, Technology, and Industrial Application (ICETIA 2016). Author(s), 2017. http://dx.doi.org/10.1063/1.4985512.
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Hempel, Laura A., Gordon Grant i Sarah L. Lewis. "CHANNEL MORPHOLOGY AND WOODY DEBRIS ARCHITECTURE IN MOUNTAIN STREAMS REFLECT DIFFERENCES IN HYDROLOGIC REGIME". W GSA Annual Meeting in Seattle, Washington, USA - 2017. Geological Society of America, 2017. http://dx.doi.org/10.1130/abs/2017am-305881.
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Singleton, Donald L., George Paraskevopoulos, Robert S. Irwin, Roderick S. Taylor i Kurt E. Leopold. "XeCl Laser Ablation Of Organic Polymers: Characterization Of Debris And Its Effect On Surface Morphology". W O-E/Fiber LASE '88, redaktorzy Anthony N. Pirri i Bernhard P. Piwczyk. SPIE, 1988. http://dx.doi.org/10.1117/12.960210.
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Demos, Stavros G., Raluca A. Negres, Rajesh N. Raman, Michael D. Feit, Kenneth R. Manes i Alexander M. Rubenchik. "Morphology of ejected debris from laser super-heated fused silica following exit surface laser-induced damage". W SPIE Laser Damage, redaktorzy Gregory J. Exarhos, Vitaly E. Gruzdev, Joseph A. Menapace, Detlev Ristau i MJ Soileau. SPIE, 2015. http://dx.doi.org/10.1117/12.2195501.
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Wang, Yachao, Jing Shi i Xinnan Wang. "Influences of Silicon Crystal Anisotropy in Nano-Machining Processes Using AFM". W ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65674.
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Atomic force microscope (AFM) machining has the potential to become an essential technology for manufacturing micro/nano-scale devices. In literature, this technique has been successfully employed to machine various types of materials, including semiconductor materials and metals. However, the effect of material anisotropy in terms of crystal direction is rarely considered in the existing studies. In this paper, we conduct nano-scratching experiments on the (1 0 0) plane of single crystal silicon surface with a diamond tip in an AFM machine. Three levels of crystal direction of nano-scratching are considered. Four levels of normal loading are applied. Machining performances are mainly evaluated by the groove morphology. Also, the wear coefficients and scratch ratio are calculated to the anti-wear performance. Based on the pile up volume and cutting volume respectively, the presence of the ploughing and cutting mechanisms is determined. The experiment results indicate that the applied normal load significantly affect the groove depth and debris morphology. The scratching direction has a pronounced effect on the friction coefficient and the calculated scratching hardness. By observing the debris morphology and cracks formation, the dependence of ductile to brittle transformation mechanism of silicon machining on the crystal direction is also discussed.
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Akchurin, Aydar, Songbo Xu, X. W. Tangpong, Tian Liu, Weston Wood i Wei-Hong Zhong. "Nanoscale Characterization of Wear Particles Produced From CNF-Reinforced HDPE Composites". W ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86149.
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Wear debris of materials used nowadays in orthopedic replacements is known to be the major cause of failures in a long-term period. Recent studies showed that the autoimmune reaction to the foreign body is not only the consequence of the material itself, but also depends on the size and shape of the wear particles. In this paper, carbon nanofiber (CNF) reinforced high density polyethylene (HDPE) debris particles were characterized both quantitatively and morphologically. Various weight concentrations (0.5 wt.%, 1 wt.% and 3 wt.%) and silane coating thicknesses (2.8 nm and 46nm) of CNFs in the nanocomposites were investigated. Wear tests were provided by a pin-on-disk tribometer with phosphate buffered saline as the lubricant. The wear debris was collected, isolated and characterized by scanning electron microscopy (SEM) at high magnifications and also by dynamic light scattering (DLS) particle sizing. The DLS measurements were in general consistent with the SEM observations. Small sphere-shaped wear particles of various diameters (predominantly less than 100 nm) were observed on the SEM images for all materials. The particles’ diameter distributions obtained by the DLS technique also showed that the mean diameters of the majority of the particles were mostly less than 100 nm. No correlation was found between the morphology, as well as the size distributions, of the debris particles and CNF concentrations or silane coating thickness in these experiments.
Raporty organizacyjne na temat "Debris morphology"
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Wallerstein, N., i C. R. Thorne. Impacts of Woody Debris on Fluvial Processes and Channel Morphology in Stable and Unstable Streams. Fort Belvoir, VA: Defense Technical Information Center, czerwiec 1995. http://dx.doi.org/10.21236/ada286853.
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Wallerstein, N., i C. R. Thorne. Impacts of Woody Debris on Fluvial Processes and Channel Morphology in Stable and Unstable Streams. Fort Belvoir, VA: Defense Technical Information Center, czerwiec 1997. http://dx.doi.org/10.21236/ada286930.
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Wallerstein, N., i C. R. Thorne. Impacts of Woody Debris on Fluvial Processes and Channel Morphology in Stable and Unstable Streams. Fort Belvoir, VA: Defense Technical Information Center, maj 1996. http://dx.doi.org/10.21236/ada286933.
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Huntley, D., D. Rotheram-Clarke, R. Cocking, J. Joseph i P. Bobrowsky. Current research on slow-moving landslides in the Thompson River valley, British Columbia (IMOU 5170 annual report). Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331175.
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Interdepartmental Memorandum of Understanding (IMOU) 5170 between Natural Resources Canada (NRCAN), the Geological Survey of Canada (GSC) and Transport Canada Innovation Centre (TC-IC) aims to gain new insight into slow-moving landslides, and the influence of climate change, through testing conventional and emerging monitoring technologies. IMOU 5107 focuses on strategically important sections of the national railway network in the Thompson River valley, British Columbia (BC), and the Assiniboine River valley along the borders of Manitoba (MN) and Saskatchewan (SK). Results of this research are applicable elsewhere in Canada (e.g., the urban-rural-industrial landscapes of the Okanagan Valley, BC), and around the world where slow-moving landslides and climate change are adversely affecting critical socio-economic infrastructure. Open File 8931 outlines landslide mapping and changedetection monitoring protocols based on the successes of IMOU 5170 and ICL-IPL Project 202 in BC. In this region, ice sheets, glaciers, permafrost, rivers and oceans, high relief, and biogeoclimatic characteristics contribute to produce distinctive rapid and slow-moving landslide assemblages that have the potential to impact railway infrastructure and operations. Bedrock and drift-covered slopes along the transportation corridors are prone to mass wasting when favourable conditions exist. In high-relief mountainous areas, rapidly moving landslides include rock and debris avalanches, rock and debris falls, debris flows and torrents, and lahars. In areas with moderate to low relief, rapid to slow mass movements include rockslides and slumps, debris or earth slides and slumps, and earth flows. Slow-moving landslides include rock glaciers, rock and soil creep, solifluction, and lateral spreads in bedrock and surficial deposits. Research efforts lead to a better understanding of how geological conditions, extreme weather events and climate change influence landslide activity along the national railway corridor. Combining field-based landslide investigation with multi-year geospatial and in-situ time-series monitoring leads to a more resilient railway national transportation network able to meet Canada's future socioeconomic needs, while ensuring protection of the environment and resource-based communities from landslides related to extreme weather events and climate change. InSAR only measures displacement in the east-west orientation, whereas UAV and RTK-GNSS change-detection surveys capture full displacement vectors. RTK-GNSS do not provide spatial coverage, whereas InSAR and UAV surveys do. In addition, InSAR and UAV photogrammetry cannot map underwater, whereas boat-mounted bathymetric surveys reveal information on channel morphology and riverbed composition. Remote sensing datasets, consolidated in a geographic information system, capture the spatial relationships between landslide distribution and specific terrain features, at-risk infrastructure, and the environmental conditions expected to correlate with landslide incidence and magnitude. Reliable real-time monitoring solutions for critical railway infrastructure (e.g., ballast, tracks, retaining walls, tunnels, and bridges) able to withstand the harsh environmental conditions of Canada are highlighted. The provision of fundamental geoscience and baseline geospatial monitoring allows stakeholders to develop robust risk tolerance, remediation, and mitigation strategies to maintain the resilience and accessibility of critical transportation infrastructure, while also protecting the natural environment, community stakeholders, and Canadian economy. We propose a best-practice solution involving three levels of investigation to describe the form and function of the wide range of rapid and slow-moving landslides occurring across Canada that is also applicable elsewhere. Research activities for 2022 to 2025 are presented by way of conclusion.
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Cooper, Christopher, Jacob McDonald i Eric Starkey. Wadeable stream habitat monitoring at Congaree National Park: 2018 baseline report. National Park Service, czerwiec 2021. http://dx.doi.org/10.36967/nrr-2286621.
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The Southeast Coast Network (SECN) Wadeable Stream Habitat Monitoring Protocol collects data to give park resource managers insight into the status of and trends in stream and near-channel habitat conditions (McDonald et al. 2018a). Wadeable stream monitoring is currently implemented at the five SECN inland parks with wadeable streams. These parks include Horseshoe Bend National Military Park (HOBE), Kennesaw Mountain National Battlefield Park (KEMO), Ocmulgee Mounds National Historical Park (OCMU), Chattahoochee River National Recreation Area (CHAT), and Congaree National Park (CONG). Streams at Congaree National Park chosen for monitoring were specifically targeted for management interest (e.g., upstream development and land use change, visitor use of streams as canoe trails, and potential social walking trail erosion) or to provide a context for similar-sized stream(s) within the park or network (McDonald and Starkey 2018a). The objectives of the SECN wadeable stream habitat monitoring protocol are to: Determine status of upstream watershed characteristics (basin morphology) and trends in land cover that may affect stream habitat, Determine the status of and trends in benthic and near-channel habitat in selected wadeable stream reaches (e.g., bed sediment, geomorphic channel units, and large woody debris), Determine the status of and trends in cross-sectional morphology, longitudinal gradient, and sinuosity of selected wadeable stream reaches. Between June 11 and 14, 2018, data were collected at Congaree National Park to characterize the in-stream and near-channel habitat within stream reaches on Cedar Creek (CONG001, CONG002, and CONG003) and McKenzie Creek (CONG004). These data, along with the analysis of remotely sensed geographic information system (GIS) data, are presented in this report to describe and compare the watershed-, reach-, and transect-scale characteristics of these four stream reaches to each other and to selected similar-sized stream reaches at Ocmulgee Mounds National Historical Park, Kennesaw Mountain National Battlefield Park, and Chattahoochee National Recreation Area. Surveyed stream reaches at Congaree NP were compared to those previously surveyed in other parks in order to provide regional context and aid in interpretation of results. edar Creek’s watershed (CONG001, CONG002, and CONG003) drains nearly 200 square kilometers (77.22 square miles [mi2]) of the Congaree River Valley Terrace complex and upper Coastal Plain to the north of the park (Shelley 2007a, 2007b). Cedar Creek’s watershed has low slope and is covered mainly by forests and grasslands. Cedar Creek is designated an “Outstanding Resource Water” by the state of South Carolina (S.C. Code Regs. 61–68 [2014] and S.C. Code Regs. 61–69 [2012]) from the boundary of the park downstream to Wise Lake. Cedar Creek ‘upstream’ (CONG001) is located just downstream (south) of the park’s Bannister Bridge canoe landing, which is located off Old Bluff Road and south of the confluence with Meyers Creek. Cedar Creek ‘middle’ and Cedar Creek ‘downstream’ (CONG002 and CONG003, respectively) are located downstream of Cedar Creek ‘upstream’ where Cedar Creek flows into the relatively flat backswamp of the Congaree River flood plain. Based on the geomorphic and land cover characteristics of the watershed, monitored reaches on Cedar Creek are likely to flood often and drain slowly. Flooding is more likely at Cedar Creek ‘middle’ and Cedar Creek ‘downstream’ than at Cedar Creek ‘upstream.’ This is due to the higher (relative to CONG001) connectivity between the channels of the lower reaches and their out-of-channel areas. Based on bed sediment characteristics, the heterogeneity of geomorphic channel units (GCUs) within each reach, and the abundance of large woody debris (LWD), in-stream habitat within each of the surveyed reaches on Cedar Creek (CONG001–003) was classified as ‘fair to good.’ Although, there is extensive evidence of animal activity...
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Rine, Kristin, Roger Christopherson i Jason Ransom. Harlequin duck (Histrionicus histrionicus) occurrence and habitat selection in North Cascades National Park Service Complex, Washington. National Park Service, kwiecień 2022. http://dx.doi.org/10.36967/nrr-2293127.
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Harlequin ducks (Histrionicus histrionicus) are sea ducks that migrate inland each spring to nest along fast-flowing mountain streams. They are considered one of the most imperiled duck species in North America and occur in two distinct populations on the Atlantic and Pacific coasts. The Pacific coast population includes Washington State, where harlequin ducks breed in the Olympic, Cascade, and Selkirk Mountains. This species is designated as a Management Priority Species by the National Park Service within North Cascades National Park Service Complex (NOCA). This report summarizes harlequin duck surveys conducted during 15 years across a 27-year period (1990 and 2017) on major streams within NOCA, and incidental observations collected from 1968–2021. The primary objectives of these surveys were to 1) document the distribution and abundance of harlequin duck observations within NOCA boundaries, 2) describe productivity (number of broods and brood size), 3) describe breeding chronology of harlequin ducks, and 4) describe habitat characteristics of breeding streams. Sixty-eight stream surveys over 15 years resulted in observations of 623 individual harlequin ducks comprising various demographics, including single adults, pairs, and broods. In addition, we collected 184 incidental observations of harlequin ducks from visitors and staff between 1968–2021. Harlequin ducks were observed on 22 separate second- to sixth-order streams throughout NOCA across the entire 53-year span of data, both incidentally and during harlequin duck surveys by Park staff. Harlequin ducks were detected on 8 of the 13 streams that were actively surveyed. Excluding recounts, 88.7% (n = 330) of individual harlequin duck observations during surveys occurred in the Stehekin River drainage. Between all surveys and incidental observations, 135 unpaired females without broods were sighted across all NOCA waterways. Thirty-nine broods were recorded between NOCA surveys and incidental observations, with a mean brood size of 3.61 (± 1.44 SD; range = 2–10). Breeding pairs were recorded as early as April 5 and were seen on streams until June 15, a period of less than seven weeks (median: May 2), but most pairs were observed within a 3-week span, between April 26 and May 17. Single females (unpaired with a male, with (an)other female(s), or with a brood) were observed on streams between April 26 and August 25 (median: July 3), though most observations were made within a 5-week period between June 12 and July 19. Habitat data collected at adult harlequin duck observation sites indicate that the birds often used stream reaches with features that are characteristic of high-energy running water. While adults occupied all instream habitat types identified, non-braided rapids and riffles were used most frequently, followed by pools and backwaters. Larger instream substrate sizes (cobbles and boulders) were present at most observation sites. Adult harlequin ducks were more often found at locations that lacked visible drifting or lodged woody debris, but drift debris was a slightly more abundant debris type. The presence of gravel bars and at least one loafing site was common. Adult harlequin ducks were more often observed in association with vegetation that offered some cover over the channel, but not where banks were undercut. The average channel width at adult observation sites was 34.0 m (range: 6-80 m; n = 114) and 27.6 m (± 15.7 m; range: 10-60 m; n = 12) at brood observation sites. Compared to adult harlequin duck sites, broods were observed more frequently in low velocity habitat (pools, backwaters), but rarely in rapids. Cobble and boulder substrates were still the most dominant substrate type. Contrary to adult ducks, broods were observed most often observed in meandering stream channels, a morphology indicative of low gradient, low velocity stream reaches. Most broods were observed in stream reaches with gravel bars, loafing sites, and...