Types Of Erosion Research Articles

Urethral Stricture Outcomes After Artificial Urinary Sphincter Cuff Erosion: Results From a Multicenter Retrospective Analysis

To evaluate the influence of both repair type and degree of cuff erosion on postoperative urethral stricture rate. Sparse literature exists regarding patient outcomes after artificial urinary sphincter (AUS) cuff erosion. Surgeons from 6 high-volume male continence centers compiled a comprehensive database of post-erosion patients to examine outcomes. This retrospective multi-institution study included 80 patients treated for AUS cuff erosions. Seventy-eight patients had specific information regarding post-cuff erosion urethral strictures. Erosion patients were categorized into 1 of 3 repair types at the time of explant surgery: catheter only, single-layer capsule-to-capsule repair (urethrorrhaphy), and formal urethroplasty. Operative notes and available medical records were extensively reviewed to collect study data. Twenty-five of 78 patients manifested a urethral stricture after AUS cuff erosion (32%). More strictures occurred among patients who underwent urethrorrhaphy (40% vs 29% for catheter only and 14% for urethroplasty). Stricture rates did not vary significantly by repair type (P = .2). Strictures occurred significantly more frequently in patients with complete cuff erosions (58%) as compared to partial erosions (25%, P = .037). A trend was detected regarding increased percentage of erosion correlating with increased stricture rate, but this did not reach statistical significance (P = .057). Partially eroded patients were more likely to undergo urethrorrhaphy repair (60%, P = .002). Urethral stricture was more likely to occur after complete cuff erosion as opposed to partial erosion in this multicenter retrospective population. Repair type, whether catheter only, urethrorrhaphy, or formal urethroplasty, did not appear to influence postoperative stricture rate.

A micromechanical approach of suffusion based on a length scale analysis of the grain detachment and grain transport processes.

Suffusion is the selective erosion of the finest particles of a soil subjected to an internal flow. Among the four types of internal erosion and piping identified today, suffusion is the least understood. Indeed, there is a lack of micromechanical approaches for identifying the critical microstructural parameters responsible for this process. Based on a discrete element modeling of non cohesive granular assemblies, specific micromechanical tools are developed in a unified framework to account for the two first steps of suffusion, namely the grain detachment and the grain transport processes. Thanks to the use of an enhanced force chain definition and autocorrelation functions the typical lengths scales associated with grain detachment are characterized. From the definition of transport paths based on a graph description of the pore space the typical lengths scales associated with grain transport are recovered. For a uniform grain size distribution, a separation of scales between these two processes exists for the finest particles of a soil

Soil erosion studies should consider the effect of water erosion on tillage erosion

S oil erosion poses a serious threat to agricultural sustainability worldwide, especially when management practices do not consider all forms of erosion and their interactions. In recent years, water and tillage erosion have contributed to approximately 90% of the total erosion hazards in cultivated fields (Govers et al. 1999). These two types of erosion accelerate soil losses, leading to serious environmental consequences, such as water pollution, land degradation, and grain reduction (Rauws and Govers 1999). Previous studies on soil movement by tillage have concentrated on the magnitude of water erosion (Alliaume et al. 2014; Ehigiator et al. 2011; Laufer et al. 2016; Salem et al. 2014; Wang et al. 2016, 2017). However, soil loss by water erosion does not have a clear effect on tillage erosion, particularly in dry (uneven rainfall distribution) and cold (massive snowmelt) regions where tillage actions occur after water erosion, i.e., tillage in the summer fallow period is typically performed to remove weeds, prepare the seed bed, and minimize soil evaporation, as is common in the dryland agriculture of Zambia and Zimbabwe (Thierfelder and Wall 2009), western United States and Great Plains (Rauws and Govers 1999; Blanco and Lal 2008; Van Oost et al. 2005), and Loess…

Study of Erosion and Sediment in the Zarak Catchment Area at Yazd Province, Iran, Using Modified P.S.I.A.C, E.P.M and B.L.M Methods and Comparison of them

Yazd province is one of the arid provinces of Iran and such regions are expected to experience wind erosion. Unlike expectation, in the Zarak catchment area that is located at Yazd province, because of fixation of the soil surface, water erosion is more than wind erosion. On the other hand, due to daily temperature changes, geological formations split and then due to heavy showers, such split blocks provide ideal conditions for surface erosion. Of course, on slopes, rill erosion can be seen. Also in the waterways, when flow discharge increase, due to concentration of the kinetic energy of water in the bends of waterway, bank erosion is found. Given the importance of soil protection programs and determining the methods of management of erosion and sediment as well as the reduction of calculation and the detailed design of the dam size at the storage dams, it is necessary to estimate total size of annual erosion and sediment in a catchment area. The Zarak catchment area is no exception. On the other hand with respect to the existence of multiple methods to do this, using a method with more reasonable data and saving cost and time, in addition providing acceptable and realistic answer is needed. Of course many parameters are involved. According to these matters, in this study, to study erosion and sediment, quantitative methods of modified Pacific Southwest Inter-Agency Committee (P.S.I.A.C) and Erosion Potential Method (E.P.M), also qualitative Bureau of Land Management (B.L.M) method were used and in the end, the results were compared. With using topographic maps and aerial photos, the initial map of each type of erosion was prepared and then by combining them with data and maps of rocks sensitivity, erosion, geology, geomorphology, slopes, vegetation types and land capabilities, etc. a base map was prepared. After that, by conducting field inspection, base map’s information was controlled and status of various erosions, slope, vegetation, condition of the bed and banks of the waterways, width and depth and materials of the bed and waterways were determined. Also erosion forms classes and their ranges were identified and the most important factors involved in the intensification of erosion were identified with using modified P.S.I.A.C, E.P.M and B.L.M methods.In the end ,the results of the three methods were compared.

Effects of collapsing gully erosion on soil qualities of farm fields in the hilly granitic region of South China

Collapsing gully erosion is a specific form of soil erosion types in the hilly granitic region of tropical and subtropical South China, and can result in extremely rapid water and soil loss. Knowledge of the soil physical and chemical properties of farmland influenced by collapsing gully erosion is important in understanding the development of soil quality. This study was conducted at the Wuli Watershed of the Tongcheng County, south of Hubei Province, China. The aim is to investigate soil physical and chemical properties of three soil layers (0–20, 20–40 and 40–60 cm) for two farmland types (paddy field and upland field) in three regions influenced by collapsing gully erosion. The three regions are described as follows: strongly influenced region (SIR), weakly influenced region (WIR) and non-influenced region (NIR). The results show that collapsing gully erosion significantly increased the soil gravel and sand content in paddy and upland fields, especially the surface soil in the SIR and WIR. In the 0–20 cm layer of the paddy field, the highest gravel content (250.94 g kg−1) was in the SIR and the lowest (78.67 g kg−1) was in the NIR, but in the upland filed, the surface soil (0–20 cm) of the SIR and the 40–60 cm soil layer for the NIR had the highest (177.13 g kg−1) and the lowest (59.96 g kg−1) values of gravel content, respectively. The distribution of gravel and sand decreased with depth in the three influenced regions, but silt and clay showed the inverse change. In the paddy field, the average of sand content decreased from 58.6 (in the SIR) to 49.0% (in the NIR), but the silt content was in a reverse order, increasing from 27.9 to 36.9%, and the average of the clay content of three regions showed no significant variation (P<0.05). But in the upland filed, the sand, silt and clay fluctuated in the NIR and the WIR. Soils in the paddy and upland field were highly acidic (pH<5.2) in the SIR and WIR; moreover lower nutrient contents (soil organic matter (SOM), total N and available N, P, K) existed in the SIR. In the 0–20 cm soil layer of the paddy field, compared with the NIR and the WIR, collapsing gully erosion caused a very sharp decrease in the SOM and total N of the SIR (5.23 and 0.56 g kg−1, respectively). But in the surface soil (0–20 cm) of the upland field, the highest SOM, total N, available N, available P and available K occurred in the NIR, and the lowest ones were in the SIR. Compared with the NIR, the cation exchange capacity (CEC) in the SIR and WIR was found to be relatively lower. These results suggest that collapsing gully erosion seriously affect the soil physical and chemical properties of farmland, lead to coarse particles accumulation in the field and decrease pH and nutrient levels.

Prospects for crowdsourced information on the geomorphic ‘engineering’ by the invasive Coypu (Myocastor coypus)

AbstractAmong the most invasive species, the Coypu (Myocastor coypus) best exemplifies the widespread effect of alien species on ecosystems. Among the impacts, the induced erosion in riverbanks has an increasing economic and social importance. Despite its significance, this type of erosion is rarely quantified, and the available information is limited to local knowledge, grey literature, and maintenance reports. This research shows the potential of freely and instantly available Structure‐from‐Motion (SfM) photogrammetry to obtain crowdsourced information based on smartphone images. The results highlight how it is possible to provide a rough estimate of the damages with relatively low or null cost of application, and limited expert knowledge and expenditure of time, depending on the scale of analysis. The proposed technique provides a fresh approach to a known long‐standing issue, offering a new source of information for farmers, researchers, wildlife managers, as well as for land managers and planners. The potential applications of such a technique and its unprecedented ease of use and very low cost offer effective tools for management plans and scientific research, providing a basis to relate eroded volumes to the functioning of the drainage system and the connected agroecosystem. The method would also enable the opportunity of participatory and opportunistic crowdsourced sensing. Further scientific research on the crowd‐based data on erosion should encourage standardisation of data gathering and accessibility, together with a public involvement in information exchange, to generate a better understanding and awareness of erosion problems also for other fields of research. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Physical behaviour of Cretaceous calcareous nannofossil ooze: Insight from flume studies of disaggregated chalk

AbstractGeomorphic features such as drifts, sediment waves and channels have been documented in the Upper Cretaceous of north‐west Europe. These features are interpreted to result from bottom currents and have been used to refine chalk depositional models and quantify palaeocirculation patterns. Chalk was first deposited as calcareous nannofossil ooze and geomorphic features are the result of sediment reworking after deposition. There is limited knowledge on the processes that govern nannofossil ooze mobility, thus forcing uncertainty onto numerical models based on sedimentological observations. This article provides an extensive view of the erosional and depositional behaviour of calcareous nannofossil ooze based on experimental work using annular flumes. A fundamental observation of this study is the significant decrease of nannofossil ooze mobility with decreasing bed porosity. Erosion characteristics, labelled as erosion types, vary with total bed porosity (φ) and applied shear stress (τ0). High‐porosity ooze (φ &gt;80%) is characterized by constant erosion rates (Em). At φ &lt;77%, however, erosion characteristics showed greater variance. Surface erosion was typically followed by transitional erosion (with asymptotically decreasing Em), and stages of erosion with constant, and exponential erosion rates. The estimated erosion thresholds (τc) vary from ca 0·05 to 0·08 Pa for the onset of surface erosion and up to ca 0·19 Pa for the onset of constant erosion (φ of 60 to 85%). Variability of deposition thresholds (τcd) from ca 0·04 to 0·13 Pa reflects the influence of variable suspended sediment concentration and τ0 on settling particle size due to the identified potential for chalk ooze aggregation and flocculation. Additionally, deposition thresholds seem to be affected by the size of eroded aggregates whose size correlates with bed porosity. Lastly, slow sediment transport without resuspension occurred in high‐porosity ooze as surface creep, forming low‐relief sedimentary features resembling ripples. This process represents a previously undescribed mode of fine‐grained nannofossil ooze transport.

Response of soil organic carbon and nitrogen stocks to soil erosion and land use types in the Loess hilly–gully region of China

Erosion influences the vertical and horizontal distribution patterns of soil and soil organic carbon (SOC) at a landscape scale. To further understand the effect of erosion on SOC and total soil nitrogen (TSN) stocks in relation to land use types after the implementation of the “Grain for Green” program in the Loess hill-gully region, the SOC, TSN, and Caesium-137 (137Cs) contents were analyzed at three selected landscape positions under three land-use types: artificial grassland (AGL), native grassland (NGL) and artificial plantation of Robinia pseudoacacia (AFL). The results showed that all land uses experienced considerable net erosion since the mid-1950s, with an average total loss depth of 2.05cm for AFL, 1.49cm for AGL, and 0.54cm for NGL. The SOC stocks in AFL and NGL were 72.3% and 26.2% lower, respectively, than that in AGL in the 0–100cm soil layer, and significant positive correlation between SOC and TSN stocks on each layer in the soil profile was observed (R2>0.90). The result showed that compared with other land-use types, AGL had a greater SOC and TSN sequestration capacity. The contents of SOC and TSN were positively correlated with the amount of 137Cs in AFL and NGL (R2=0.97, 0.97 for AFL, respectively, and R2=0.90, 0.90 for NGL, respectively; n=3), whereas no significant correlation was found in AGL (R2=0.41, 0.01, respectively; n=3). The results indicated that AGL was an optimal choice to mitigate soil carbon and nitrogen loss and to increase C and N sequestration in the Loess hilly–gully region. A complex process should be considered for the distribution patterns of SOC and TSN after afforestation since 1999.

137Cs tracing dynamics of soil erosion, organic carbon, and total nitrogen in terraced fields and forestland in the Middle Mountains of Nepal

The Middle Mountains is one of the regions of Nepal most vulnerable to water erosion, where fragile geology, steep topography, anomalous climatic conditions, and intensive human activity have resulted in serious soil erosion and enhanced land degradation. Based on the Cs-137 tracing method, spatial variations in soil erosion, organic carbon, and total nitrogen (TN) in terraced fields lacking field banks and forestland were determined. Soil samples were collected at approximately 5 m and 20 m intervals along terraced field series and forestland transects respectively. Mean 137Cs inventories of the four soil cores from the reference site was estimated at 574.33 +/- 126.22 Bq m(-2) (1 Bq (i.e., one Becquerel) is equal to 1 disintegration per second (1 dps)). For each terrace, the Cs-137 inventory generally increased from upper to lower slope positions, accompanied by a decrease in the soil erosion rate. Along the entire terraced toposequence, Cs-137 data showed that abrupt changes in soil erosion rates could occur between the lower part of the upper terrace and the upper part of the immediate terrace within a small distance. This result indicated that tillage erosion is also a dominant erosion type in the sloping farmland of this area. At the same time, we observed a fluctuant decrease in soil erosion rates for the whole terraced toposequence as well as a net deposition at the toe terrace. Although steep terraces (lacking banks and hedgerows) to some extent could act to limit soil sediment accumulation in catchments, soil erosion in the terraced field was determined to be serious. For forestland, with the exception of serious soil erosion that had taken place at the top of slopes due to concentrated flows from a country road situated above the forestland site, spatial variation in soil erosion was similar to the "standard" water erosion model. Soil organic carbon (SOC) and TN inventories showed similar spatial patterns to the Cs-137 inventory for both toposequences investigated. However, due to the different dominant erosion processes between the two, we found similar patterns between the < 0.002 mm soil particle size fraction (clay sized) and Cs-137 inventories in terraced fields, while different patterns could be found between Cs-137 inventories and the < 0.002 mm soil particle size fraction in the forestland site. Such results confirm that Cs-137 can successfully trace soil erosion, SOC and soil nitrogen dynamics in steep terraced fields and forestland in the Middle Mountains of Nepal.

Une interposition prothétique synthétique inter-vésico-vaginale implantée par voie vaginale diminue-t-elle le risque de récidive de cystocèle ? Recommandations pour la pratique clinique

The use of prosthetic surgery by vaginal route has been widely used to try to reduce the risk of prolapse recurrence in the surgical treatment of vaginal cystoceles. Specific complications including type of erosion have led to randomized studies comparing surgery by vaginal route with and without use of Mesh. This work is based on a systematic review of the literature (PubMed, Medline, Cochrane Library, Cochrane database of systemactic reviews, EMBASE) for meta-analyzes, randomized trials, registries, literature reviews, controlled studies and major not controlled studies, published on the subject. Its implementation has followed the methodology of the HAS on the recommendations for clinical practice, with a scientific argument (with the level of evidence, NP) and a recommendation grade (A, B, C, and professional agreement (AP)). The use of inter-vesicovaginal synthetic mesh improves the anatomical result compared to the autologous surgery for the treatment of cystocele (NP1). However, there is no difference in the functional outcome and there is an increase in the number of reoperations related to specific complications, including vaginal erosions. If the use of inter-vesicovaginal synthetic mesh improves the anatomical result compared to the autologous surgery for the treatment of cystocele (NP1), no difference in functional outcome and the increased number of related reoperations specific complications including vaginal erosions, do not argue for the systematic use of mesh in the treatment of primary cystocele. It must be discussed case by case basis taking into account a risk-benefit uncertain at long-term (grade B). Its use should be supported by additional studies focused on specific populations at risk of recurrence. © 2016 Published by Elsevier Masson SAS.

Comparison of circulatory disorders in the lungs revealed by X-ray and single-photon emission computed tomography with articular changes in magnetic resonance imaging in patients with rheumatoid arthritis

Introduction. Rheumatoid arthritis (RA) affects not only the joints but also other organs. Lung disease is one of the leading manifestations of RA, and detection of these changes remains a diagnostic challenge. Delayed diagnosis of pulmonary involvement in the pathogenesis of RA often leads to development of severe forms which aggravate prognosis and decrease of the quality of life. Identify the characteristics and prognostic significance of CT and SPECT symptoms involving respiratory system in patients with RA depending on the stage of the disease and the destruction of hand joints as detected by MRI. Methods. To evaluate favorable and unfavorable predictors of RA clinical course and detect changes in the lung using modern methods of imaging: magnetic resonance, computed tomography and single-photon emission computed tomography. Results. A set of signs identified by CT and SPECT was analyzed corresponding to the presence of different types of erosions detected by MRI. Pleural adhesions, symptoms of bronchial obstruction (uneven ventilation, «air trap»), and signs of vasculitis were observed in all stages of the disease. With the progression of the disease, bullous emphysema-type deforming bronchitis symptoms and associated comorbid processes in the lung tissue were observed. Conclusions. For all types of active RA in patients with a high frequency revealed signs of bronchial obstruction and concomitant manifestations of vasculitis. These results require the inclusion of X-ray and single photon emission computed tomography of the chest in the algorithm of diagnostic evaluation of the patients with RA to identify and assess changes related primarily to the blood circulation, have prognostic significance and impact on treatment regimen.

Prediction of pathological fracture of the femoral shaft with an osteolytic lesion using a computed tomography-based nonlinear three-dimensional finite element method.

Physicians radiologically estimate the reduction in bone strength based on the size or location of bone tumors. The goal of this study was to clarify the relationship between the size or location of a bony defect and its mechanical strength using a computed tomography-based three-dimensional finite element method. Computed tomography data of the right femur from two volunteers (one healthy male and one female patient with primary osteoporosis) were used for the present study. A spherical defect of various sizes and locations at the level of the isthmus of the femoral shaft was created on the three-dimensional finite element models to simulate the osteolytic bone tumor. We classified these defects into three types: inner erosion, cortical disruption, and outer erosion. Two types of mechanical testing were performed: axial compression and torsion. In the axial compression testing of the healthy male subject, the correlation coefficients between the defect rate and the failure load in the cortical disruption type, inner erosion type, and outer erosion type were-0.916,-0.358, and-0.106, respectively. In the torsion testing, they were-0.8744,-0.9001, and-0.8907, respectively. In the axial compression testing of the osteoporotic female subject, the correlation coefficients in the cortical disruption type, inner erosion type, and outer erosion type were-0.754,-0.621, and-0.158, respectively. In the torsion testing, they were-0.9199,-0.5098, and-0.8363, respectively. In both tests, the defect rate of the cortex increased and the bone strength decreased, especially in the cortical disruption type. The results of the present study demonstrate that osteolytic bone tumors can weaken the bone strength, particularly when perforation of the cortex occurs via tumor invasion. These results may be useful for risk assessment of pathological fractures due to primary and metastatic osteolytic bone tumors in clinical practice.

Landslide characteristics in the area of Xiaolin Village during Morakot typhoon

Xiaolin, a small village in southern Taiwan, was completely buried by a deep-seated landslide during the extreme rainfall of Typhoon Morakot in 2009, and 500 people were killed. This disaster caused great public concern. This study examines the rainfall-induced landslide characteristics in the area and their correlations with various susceptibility factors. We emphasize the importance of producing an accurate landslide inventory using visual interpretation and propose a new systematized set of subcategories of susceptibility factors, especially stream factors. We used satellite images, digital elevation models, and landslide inventories from before and after the disaster to perform spatial analysis using geographic information system (GIS) tools. Of the topographical factors considered, only slope aspect was important, and the landslides bore little relation to tectonic lines. The stream factors had the strongest influence on these landslides. Almost 100 % of the landslide area was related to various types of erosion caused by the stream network. Most of the large-scale landslides were induced by headward erosion, and all occurred on dip or oblique slopes. Thus, a combination of dip or oblique slope types and stream factors resulted in more landslides, which suggests that landslides are often induced by a combination of multiple factors.

Experimental study on piping in sandy gravel foundations considering effect of overlying clay

The influence of the overlying clay on the progression of piping in the sandy gravel foundation of water-retaining structures is often neglected. In order to study this influence, an experimental investigation was conducted on a laboratory-scale model. It was discovered that the critical hydraulic gradient and the area of the piping tunnel increase when the overlying clay thickens. With a thicker clay layer, erosion of the sandy gravel below the clay layer occurs later, but, once the erosion starts, the erosion rate is very high and the average velocity of water seeping through the cross-section of the sandy gravel increases rapidly due to the low deformability of the thick clay layer. Furthermore, it was found that the progression of piping is a complicated and iterative process involving erosion of fine particles, clogging of pores, and flushing of the clogged pores. Two types of erosion have been identified in the progression of piping: one causes the tunnel to advance upstream, and the other increases the depth of the tunnel. The results show that the overlying clay is an important factor when evaluating piping in sandy gravel foundations of water-retaining structures.

Erosion processes in karst landscapes of the Russian plain northern taiga, based on digital elevation modeling

This paper considers the problems of the potential development of erosion processes in the natural landscapes of northern taiga in the Russian plain. It is considered that in forest ecosystems, erosion processes are slow and are weakly reflected in the terrain. However, the situation changes radically if the vegetation cover integrity is violated, which is inevitable with the modern methods of developing northern territories. Furthermore, global changes in average annual temperatures and the occurrence of karst processes may be the reason behind the development of erosion processes. The authors suggest a method for determining territories with a varying occurrence probability of erosional processes, based on digital elevation modelling. The territory of the Pinezhsky Nature Reserve (Arkhangelsk region) was chosen as the test plot. Direct field studies were previously used to detect exogenous geological processes in this territory. The authors were the first to suggest digital elevation modelling as a method that allows determining the potential danger of erosion in karst landscapes of the northern taiga. The geomorphometric studies resulted in the determination of areas with the greatest and lowest occurrence probability of erosion processes in the Pinezhsky Nature Reserve. It was established that the most significant erosion type was linear erosion, represented by incised river valleys and karst ravines. Sheet erosion is less significant and occurs as sinkholes, local declines, and chasms over the valleys of subterranean rivers.

Integrated Use of GCM, RS, and GIS for the Assessment of Hillslope and Gully Erosion in the Mushi River Sub-Catchment, Northeast China

The black soil region of Northeast China has suffered from severe soil erosion by water. Hillslope and gully erosion are the main erosion types. The objective of this research was to integrate the assessment of hillslope and gully erosion and explore spatial coupling relations between them in the Mushi River sub-catchment using geographical conditions monitoring (GCM) including remote sensing (RS) and geographic information system (GIS) techniques. The revised universal soil loss equation (RUSLE) model and visual satellite image interpretation were used to evaluate hillslope and gully erosion, respectively. The results showed that (1) the study area as a whole had slight erosion due to rill and sheet erosion, but suffered more serious gully erosion, which mainly occurs in cultivated land; (2) GCM contributed to the overall improvement of soil erosion assessment, but the RUSLE model likely overestimates the erosion rate in dry land; (3) the hillslope and gully erosion were stronger on sunny slopes than on shady slopes, and mainly occurred at middle elevations. When the slope was greater than 15 degrees, the slope was not the main factor restricting the erosion, while at steeper slopes, the dominant forest land significantly reduced the soil loss; (4) trends of gully erosion intensity and density were not consistent with the change in soil erosion intensity. To our knowledge, this study was one of the first that attempted to integrate gully erosion and hillslope erosion on a watershed scale. The findings of this study promote a better understanding of the spatial coupling relationships between hillslope and gully erosion and similarly indicate that GCM, RS, and GIS can be used efficiently in the hilly black soil region of Northeast China to assess hillslope and gully erosion.

Development of Wall-Thinning Evaluation Procedure for Nuclear Power Plant Piping—Part 1: Quantification of Thickness Measurement Deviation

Pipe wall thinning by flow-accelerated corrosion and various types of erosion is a significant and costly damage phenomenon in secondary piping systems of nuclear power plants (NPPs). Most NPPs have management programs to ensure pipe integrity due to wall thinning that includes periodic measurements for pipe wall thicknesses using nondestructive evaluation techniques. Numerous measurements using ultrasonic tests (UTs; one of the nondestructive evaluation technologies) have been performed during scheduled outages in NPPs. Using the thickness measurement data, wall thinning rates of each component are determined conservatively according to several evaluation methods developed by the United States Electric Power Research Institute. However, little is known about the conservativeness or reliability of the evaluation methods because of a lack of understanding of the measurement error. In this study, quantitative models for UT thickness measurement deviations of nuclear pipes and fittings were developed as the first step for establishing an optimized thinning evaluation procedure considering measurement error. In order to understand the characteristics of UT thickness measurement errors of nuclear pipes and fittings, round robin test results, which were obtained by previous researchers under laboratory conditions, were analyzed. Then, based on a large dataset of actual plant data from four NPPs, a quantitative model for UT thickness measurement deviation is proposed for plant conditions.

Socioeconomic Impact Assessment of Highway Drainage Outlet Erosion, Case Study of Mekelle to Adigrat Highway, Tigray, Ethiopia

Roads are backbones for one’s country economy and play great role in public’s mobility. To make these well function proper drainage systems must have; and these drainages are major causes for land degradation and gully formation. This assessment was conducted in selected road drainage (bridges, culverts and side channels) of Mekelle to Adigrat 113 Km road. The study focuses types, causes, impact of road drainage erosion, and government attentions to protect erosions and possible remedial measures by selecting 60 farmers which are 26.67% of the total population in the study area (225) randomly downstream of the road; 17 DAs selected based on their profession of 4 Woreda experts. Major findings from the socioeconomic assessment using interviewing and field survey are 1) There are three types of erosions (splash and sheet, rill, and gully) but most common is gullying in 87 culverts (44.39%) 2) Major causes of gully from interview of experts are: 38.81% lack of conservation works upstream and downstream of the structure, 14.93% design problem and lack of appropriate energy dissipaters, 20.90% improper land use practices.

Оценка состояния водно-земельных ресурсов Азербайджана

In the article the problems of assessment of water are concidered according to land resources of Azerbaijan. The authors note that currently in the country out of the total turnover of the land displays a wide area unsuitable for agricultural production due to the construction of individual buildings and structures, elevation of groundwater level, the development of various types of erosion and for other reasons. So, one person in 1959 had 0.36 ha of arable land, 1970 – 0.23 ha in 1979 – 0.21 hectares, in 2006 dropped to 0.155 hectares currently, more than 42.8% of the whole territory of the Republic (70...85 % in some regions) is exposed to various erosive processes. A critical question is the availability suitable for agriculture water resources. By estimations of authors of the water resources of the country amount to 32.5 billion m3, and in dry years this figure is reduced to of 23.16 billion m3. The results of the study revealed that up to 96 % of irrigated land is watered mainly traditional irrigation methods (furrow and overlap, superficial way), and in other ways with the use of low-intensity progressive water saving technologies of irrigation systems with up to 5 % of the total irrigated land. According to the researches, in 2020 the total annual value of water resources per capita in Azerbaijan will be 2 times less than in Armenia, and 7 times less than in Georgia. It is proposed to increase the efficiency of agricultural production in the production unit of crop production from use of water resources by the year 2025 at the level of 1 kg/m3 and 1.5 kg/m3 by 2050.

Incorporating Uncertainty into Backward Erosion Piping Risk Assessments

Backward erosion piping (BEP) is a type of internal erosion that typically involves the erosion of foundation materials beneath an embankment. BEP has been shown, historically, to be the cause of approximately one third of all internal erosion related failures. As such, the probability of BEP is commonly evaluated as part of routine risk assessments for dams and levees in the United States. Currently, average gradient methods are predominantly used to perform these assessments, supported by mean trends of critical gradient observed in laboratory flume tests. Significant uncertainty exists surrounding the mean trends of critical gradient used in practice. To quantify this uncertainty, over 100 laboratory-piping tests were compiled and analysed to assess the variability of laboratory measurements of horizontal critical gradient. Results of these analyses indicate a large amount of uncertainty surrounding critical gradient measurements for all soils, with increasing uncertainty as soils become less uniform.