نتایج جستجو برای: دستگاه lwd
تعداد نتایج: 31267 فیلتر نتایج به سال:
با توجه به این که در روش طراحی مکانیستیک تجربی مدول برجهندگی به عنوان یکی از پارامتر های اصلی طراحی می-باشد و آزمایش مدول برجهندگی وقت گیر و پرهزینه است و نیاز به تخصص دارد، لذا توسعه روابط بین این پارامتر و پارامتر های دیگری مثل cbr که بیان کننده رفتار خاک می باشد کاملا ضروری است. در این مقاله آزمایش های میدانی و آزمایشگاهی به منظور ارزیابی پتانسیل استفاده از دستگاه lwd برای اندازه گیری درجای ...
مدول برجهندگی خاک بستر یکی از پارامترهای مهم در طراحی روسازی است که با انجام آزمایش سه محوری سیکلی روی نمونه های استوانه ای به دست می آید . با توجه به پیچیدگی و مشکلات این آزمایش، انجام آزمایش های میدانی به شرط وجود همبستگی مناسب بسیار مفید خواهد بود . امروزه کاربرد آزمایش های غیرمخرب روسازی در جهان رو به گسترش است . سرعت بالای انجام آزمایش، دقت زیاد تجهیزات اندازه گیری، غیرمخرب ...
Large woody debris (LWD: > 10 cm diameter and > 1 m in length) in stream channels of forested regions in North America is an essential ecosystem component. This article summarizes information from the literature on the spatial and temporal variability of LWD abundance, distribution and age; the processes of LWD delivery and elimination; and the influence of LWD on material retention, habitat fo...
Riparian large woody debris (LWD) recruitment simulations have traditionally applied a random angle of tree fall from two well-forested stream banks. We used a riparian LWD recruitment model (CWD, version 1.4) to test the validity these assumptions. Both the number of contributing forest banks and predominant tree fal l d irect ion s igni f icant ly inf luenced s imulated r iparian LWD del iver...
Wine-Spring Creek basin, in the mountains of North Carolina’s Nantahala National Forest, is an ecosystem management demonstration site, iu which ecological concepts for management and restoration are tested. Large woody debris (LWD) is an important link between streams and the adjacent riparian forest, but evidence for the connection between LWD and trout in southern Appalachian streams is limi...
This study used 20-year records of stream channel change and wood to test hypotheses about the long-term influence of large woody debris (LWD) on channel morphology, channel stability, and sediment dynamics in a steep, boulder-rich mountain stream. We compared two nearly adjacent reaches of third-order Mack Creek over the period 1978–1997 after virtually all wood was removed from the channel of...
BACKGROUND Knowledge on microclimate conditions under artificial shades in a ginseng field would facilitate climate-aware management of ginseng production. METHODS Weather data were measured under the shade and outside the shade at two fields located in Gochang-gun and Jeongeup-si, Korea, in 2011 and 2012 seasons to assess temperature and humidity conditions under the shade. An empirical appr...
An LWD acoustic wave can move the excess charge in the electric double layer along the borehole wall to generate a streaming electric field. This thesis is an experimental and theoretical investigation of the electric field induced by the multipole LWD acoustic wave. The main goal of this thesis is to understand the mechanism in the seismoelectric conversion under the LWD geometry and prove the...
Absrract.-Log length exerted a critical influence in stabilizing large woody debris (LWD) pieces added as an experimental stream restoration technique. Logs longer than the average bank-full channel width (5.5 m) were significantly less likely to be displaced than logs shorter than this width. The longest log in stable log groups was significantly longer than the longest log in unstable groups....
Large woody debris (LWD) plays a critical structural role in riparian ecosystems, but it can be difficult and time-consuming to quantify and survey in the field. We demonstrate an automated method for quantifying LWD using aerial LiDAR and object-based image analysis techniques, as well as a manual method for quantifying LWD using image interpretation derived from LiDAR rasters and aerial four-...
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