Cosmogenic nuclides (10Be and 26Al) erosion rate constraints in the Badain Jaran Desert, northwest China: implications for surface erosion mechanisms and landform evolution

2018 ◽  
Vol 23 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Tong Zhao ◽  
Wenjing Liu ◽  
Zhifang Xu ◽  
Taoze Liu ◽  
Sheng Xu ◽  
...  
Keyword(s):  
Erosion Rate ◽  
Northwest China ◽  
Cosmogenic Nuclides ◽  
Surface Erosion ◽  
Badain Jaran Desert ◽  
Landform Evolution ◽  
Erosion Mechanisms ◽  
Rate Constraints

scholarly journals Combined linear regression and Monte Carlo approach to modelling exposure age depth profiles

2021 ◽  
Author(s):  
Yiran Wang ◽  
Michael E. Oskin
Keyword(s):  
Monte Carlo ◽  
Erosion Rate ◽  
Profile Analysis ◽  
Radioactive Decay ◽  
Northwest China ◽  
External Information ◽  
Surface Erosion ◽  
Linear Inversion ◽  
Practical Applications ◽  
Depth Profiles

Abstract. We introduce a set of methods for analyzing cosmogenic-nuclide depth profiles that formally integrates surface erosion and muogenic production, while retaining the advantages of the linear inversion. For surfaces with erosion, we present solutions for both erosion rate and total eroded thickness, each with their own advantages. For practical applications, erosion must be constrained from external information, such as soil-profile analysis. By combining linear inversion with Monte Carlo simulation of error propagation, our method jointly assesses uncertainty arising from measurement error and erosion constraints. Using example depth profile data sets from the Beida River, northwest China and Lees Ferry, Arizona, we show that our methods robustly produce comparable ages for surfaces with different erosion rates and inheritance. Through hypothetical examples, we further show that both the erosion rate and eroded-thickness approaches produce reasonable age estimates so long as the total erosion less than twice the nucleon attenuation length. Overall, lack of precise constraints for erosion rate tends to be the largest contributor of age uncertainty, compared to the error from omitting muogenic production or radioactive decay.

Machining performance evaluation under recently developed sustainable HAJM process of zirconia ceramic using hot SiC abrasives: An experimental and simulation approach

2021 ◽  
pp. 095440622110101
Author(s):  
Subhadip Pradhan ◽  
Sudhansu Ranjan Das ◽  
Pankaj Charan Jena ◽  
Debabrata Dhupal
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Erosion Rate ◽  
Research Work ◽  
Abrasive Particle ◽  
Target Surface ◽  
Zirconia Ceramic ◽  
Surface Erosion ◽  
Vast Number ◽  
Micro Channels

The proposed research work accomplishes the experimental study and computational fluid dynamics (CFD) technique for erosive footprint prediction extent in hot abrasive jet machining (HAJMing) constraints on target surface erosion rate, surface roughness of intricately shaped tapered holes generation. The CFD-obtained footprints were in superior agreement with experimentally measured data. HAJMing process uses a relatively high speed air-hot abrasive stream to produce both high accuracy micro-channels and tapered holes. HAJM also defines itself phenomenal competence over all advanced manufacturing techniques due to its growing demands for better surface reliability with defects (mostly stress, heat) free surfaces. Zirconia is widely accepted and associated in the non-conventional machining processes and industries with the years of track on record of proven performance in a vast number of brittle materials. Most perceptible act in this research is the selection of abrasive particle to achieve the appropriate intricate shaped holes on zirconia ceramic with hot silicon carbide (SiC) abrasives. Machining of these features are done with varying the abrasive temperature. Optical microscopic view was considered for the generation of machined holes during HAJMing. All the experimental data were presented to study the effect of machining constraints on target surface erosion rate and surface roughness using HAJMing. Single impact experiments were executed to measure the target surface erosion due to impact of individual hot silicon carbide abrasive particles. An experimental setup has been designed to conduct the machining trials using Box-Behnken design of experiments. It is also shown that the generated workpiece surface contour and erosion rate are the function of machining constraints which have a negligible influence on air-abrasive flow characteristics. This research work also deals with the sustainability assessment under environmental-friendly hot abrasive-assisted machining conditions.

scholarly journals Aeolian particle transport inferred using a ~150-year sediment record from Sayram Lake, arid northwest China

2015 ◽  
Author(s):  
Long Ma ◽  
Jinglu Wu ◽  
Jilili Abuduwaili ◽  
Wen Liu
Keyword(s):  
Sediment Cores ◽  
Northwest China ◽  
Tianshan Mountains ◽  
Transport Processes ◽  
Dust Storms ◽  
Surface Erosion ◽  
Sediment Record ◽  
Aeolian Transport ◽  
End Members ◽  
The Impact

<p>We studied sediment cores from Sayram Lake in the Tianshan Mountains of northwest China to evaluate variations in aeolian transport processes over the past ~150 years. Using an end-member modeling algorithm of particle size data, we interpreted end members with a strong bimodal distribution as having been transported by aeolian processes, whereas other end members were interpreted to have been transported by fluvial processes. The aeolian fraction accounted for an average of 27% of the terrigenous components in the core. We used the ratio of aeolian to fluvial content in the Sayram Lake sediments as an index of past intensity of aeolian transport in the Tianshan Mountains. During the interval 1910-1930, the index was high, reflecting the fact that dry climate provided optimal conditions for aeolian dust transport. From 1930-1980, the intensity of aeolian transport was weak. From the 1980s to the 2000s, aeolian transport to Sayram Lake increased. Although climate in northwest China became more humid in the mid-1980s, human activity had by that time altered the impact of climate on the landscape, leading to enhanced surface erosion, which provided more transportable material for dust storms. Comparison of the Lake Sayram sediment record with sediment records from other lakes in the region indicates synchronous intervals of enhanced aeolian transport from 1910 to 1930 and 1980 to 2000.</p>

Prediction of Erosion of Polyetherimide and Its Composites Using Response Surface Methodology

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Avinash A. Thakre
Keyword(s):  
Response Surface Methodology ◽  
Steady State ◽  
Glass Fiber ◽  
Response Surface ◽  
Impact Velocity ◽  
Erosion Rate ◽  
Quadratic Model ◽  
Impingement Angle ◽  
Glass Fiber Composites ◽  
Erosion Mechanisms

This paper presents an approach to establish the model for predicting the steady-state erosion rate of polyetherimide and its glass fiber composites. Three-factor and two-level, face-centered composite design is used for experimentation. The parameters which affect the erosion rate are selected as glass fiber percentage (0–40%), impingement angle (30 deg–90 deg), and impact velocity (30–90 m/s). Response surface methodology is used to derive second-order quadratic model with interactions. Investigation showed all the parameters have significant effect on controlling steady-state erosion rate of these composites. The interactions of impact velocity-fiber percentage and impact velocity-impingement angle are significant. The increase in erosion rate with the increase in impact velocity is found to be satisfying a power law. Maximum erosion rate for these composites found at around 45 deg–60 deg impingement angle indicates their semiductile erosion behavior. Scanning electron microscopy photographs indicate ploughing, microcutting, development of cracks, and exposure of fibers as the dominating erosion mechanisms for these composites.

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