Slope Degree Research Articles

Particle Swarm Optimization Algorithm in Numerical Simulation of Saturated Rock Slope Slip

With the continuous popularization and development of highway traffic in mountainous areas, the number of rock slopes is also increasing. In order to improve the stability of rock slope and reduce the harm caused by slope slip, this paper carries out numerical simulation of rock slope sliding based on particle swarm optimization algorithm. Firstly, this paper combines the differential evolution algorithm and simplex method to improve the global and local search ability of particle swarm optimization (PSO) algorithm and analyzes the performance of the algorithm. ABAQUS software is used to simulate rock slope sliding, the finite element method is used to analyze the stability of rock slope, and LS-DYNA program is used to simulate rockfall impact rock slope. During the numerical simulation, the improved algorithm is used to analyze all the data. Experimental data show that the improved PSO algorithm converges after nearly 100 iterations and the convergence speed and optimization accuracy are high. In the numerical simulation, the average failure probability of the left and right sides of the main section at the top, middle, and foot of the slope is 0.0820 and 0.0723, 0.0772 and 0.0492, and 0.0837 and 0.0677, respectively, indicating that the overall instability probability of the left side of the rock slope is higher than that of the right side. The rock slope with the same direction through joint is mainly affected by the joint at the toe of the slope, the rock slope with reverse through joint is mainly affected by the joint in the slope, and the sliding occurs from the middle to both ends. In addition, with the increase of the size and height of rockfall, the total energy of rock slope is also increasing, and the possibility and degree of rock slope sliding are higher. This shows that the improved particle swarm optimization algorithm can effectively analyze some factors affecting slope slip in numerical simulation of saturated rock slope slip.

Prioritization of water erosion–prone sub-watersheds using three ensemble methods in Qareaghaj catchment, southern Iran

Water-induced erosion poses severe harm to the sustainable development of land and water resources that is essential for attaining agricultural sustainability in Qareaghaj catchment of Fars Province, Iran. This study evaluates the topo-hydrological, morphometric, climatic, and environmental characteristics of Qareaghaj catchment for prioritizing the sub-watersheds that are susceptible to erosion caused by water. We tested and compared a novel ensemble multi-criteria decision-making (MCDM) model, namely the weighted aggregated sum product assessment-analytical hierarchy process (WASPAS-AHP) with prevailing benchmark ensemble MCDM models including VlseKriterijumska optimizacija I Kompromisno Resenje (VIKOR)-AHP and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)-AHP for ranking sub-watersheds and determining the most significant parameter that influences water erosion (WE) in Qareaghaj catchment. The outcome of weights using pairwise comparison matrix (PCM) of AHP reveals that normalized difference vegetation index (NDVI), mean annual rainfall (MAR), slope degree (SD), and slope length and steepness factor (LS) governs the WE in Qareaghaj catchment. The prioritization rankings of sub-watersheds obtained using the VIKOR-AHP, TOPSIS-AHP, and WASPAS-AHP models demonstrate that SW31, SW63, and SW94 had the highest priority rank with a score of 0.047, 0.69, and 0.477, respectively. The comparison of rankings from the models using Spearman's correlation coefficient tests (SCCT) and Kendall's tau correlation coefficient tests (KTCCT) revealed that WASPAS-AHP had a higher correlation with TOPSIS-AHP and VIKOR-AHP ensemble models. The outcome of MCDM models was validated based on the erosion potential method (EPM), which displayed that the VIKOR-AHP model was better for mapping the erosion susceptibility than TOPSIS-AHP and WASPAS-AHP models. Thus, the erosion susceptibility mapping based on the VIKOR-AHP ensemble model can be considered for developing new strategies and land use policies in order to control WE in Qareaghaj catchment.

GIS-based ensemble modelling of fuzzy system and bivariate statistics as a tool to improve the accuracy of landslide susceptibility mapping

The primary objective is to propose and verify an ensemble approach based on fuzzy system and bivariate statistics for landslide susceptibility assessment (LSA) at Azarshahr Chay Basin (Iran). In this regard, various integrations of fuzzy membership value (FMV), frequency ratio (FR), and information value (IV) with index of entropy (IOE) were investigated. Aerial photograph interpretations and substantial field checking were used to identify the landslide locations. Out of 75 identified landslides, 52 (≈70%) locations were utilized for the training of the models, whereas the remaining 23 (≈30%) cases were employed for the validation of the models. Fourteen landslide conditioning factors including altitude, slope aspect, slope degree, lithology, distance to fault, curvature, land use, distance to river, topographic position index (TPI), topographic wetness index (TWI), stream power index (SPI), normalized difference vegetation index (NDVI), distance to road, and rainfall were prepared and utilized during the analysis. The $$\mathrm{FMV}\_\mathrm{IOE}$$ , $$\mathrm{FR}\_\mathrm{IOE}$$ , and $$\mathrm{IV}\_\mathrm{IOE}$$ models were designed utilizing the dataset for training. Finally, to validate as well as to compare the model’s predictive abilities, the statistical measures of receiver operating characteristic (ROC), including sensitivity, accuracy, and specificity, were employed. The accuracy of 92.7, 92.5, and 91.8% of the models such as $$\mathrm{FMV}\_\mathrm{IOE}$$ , $$\mathrm{FR}\_\mathrm{IOE}$$ , and $$\mathrm{IV}\_\mathrm{IOE}$$ ensembles, respectively, was by the area under the receiver operating characteristic (AUROC) values developed from the ROC curve. For the validation dataset, the $$\mathrm{FMV}\_\mathrm{IOE}$$ model had the maximum sensitivity, accuracy, and specificity values of 95.7, 91.3, and 87.0%, respectively. Thus, the ensemble of FMV_IOE was introduced as a promising and premier approach that could be used for LSA in the study area. Also, IOE results indicated that altitude, lithology, and slope degree were main drivers of landslide occurrence. The results of the present research can be employed as a platform for appropriate basined management practices in order to plan the highly susceptible zones to landslide and hence minimize the expected losses.

DInSAR and statistical modeling to assess landslides: The case study of Sierras Chicas (central Argentina)

The main goal of this investigation was to assess landslides in the steep West-facing slope of the Sierras Chicas mountains in central Argentina using two complementary approaches: Differential SAR interferometry (DinSAR) and statistical modeling. The combination of the geological characteristics of the area, wildfires, intense rainfall events and human disturbances have made the area highly susceptible to landslides. This condition has been recently aggravated with the construction of a roadway. In this work, we applied DInSAR methods to explore the suitability of COSMO-SkyMed (CSK) acquisitions to measure displacements and we used Sentinel-1 C-band images for accuracy comparison. In addition, Generalized Linear Models were fitted to identify landslide-conditioning factors. Based on the results obtained, Sentinel-1 proved to be the most adequate source of images to perform interferometry, in contrast to Cosmo Skymed imagery that showed very poor coherence in the study area. The statistical modeling identified slope degree, distance to roads and fire frequency as the main variables explaining landslide occurrence on the west escarpment of the Sierras Chicas. Results will hopefully contribute to improving future applications of SAR interferometry both in the study area and others with similar characteristics, as well as the tools and knowledge for decision making in engineering and urban development projects in order to minimize risk.

GIS-based multi-criteria decision making and entropy approaches for groundwater potential zones delineation

In arid and semi-arid, due to the lack of surface water, groundwater plays key role in people survival. Therefore, assessing groundwater potential zones is vital to conserve and manage this resource properly. The main object of this study was to compare two methods of AHP and entropy for delineating groundwater potential zone in arid region of Iran. For this regard, withdraw in groundwater level in 16 piezometer wells along with eight GWP conditioning factors of slope degree, stream power index (SPI), landuse, geology; rainfall volume, elevation, soil and lineament density have been considered in the training process while the discharge in the other 16 wells was involved in verifying process of the two models. GWP maps were provided by overlaying all the thematic maps in terms of the obtained weights from AHP and entropy methods. Finally, the models performance was compared through statistical measures of Sensivity, Specificity and True Skill Statistics (TSS). The results show that IOE model (TSS = 0.16) have higher prediction performance than AHP approach (TSS = 0). Therefore, IOE was more promising tools for GWP modeling.

Geospatial Modeling of Landslide Vulnerability and Simulating Spatial Correlation with Associated Factors in Bandarban District

The present study aims at identifying and predicting landslide vulnerable areas in Bandarban District of Chittagong Hill Tracts (CHT) using weighted overlaying of the multiple geospatial layers to determine landslide hazard areas. The historical landslide inventory map was prepared using Google Earth image and through PRA technique. Then ten landslide triggering factors including landuse, rainfall, slope, elevation, cut-fill, soil types, geology, distance to rivers, roads and stream orders, population density, income, education of the inhabitants were chosen as effective factors on a landslide in the study area. Subsequently, the landslide vulnerability map was constructed using the weighted overlay model in Geographic Information System (GIS). Bandarban District has 348 landslides vulnerable locations. Among them, 6 are extremely vulnerable and 342 are highly vulnerable to landslides. Model results show that the Upazila Ruma and Thanchi are extremely vulnerable to landslides. About 91 percent of the landslides will occur within 10 degrees of slope, about 65 percent will occur within 50 meters elevation. The model shows that there is a strong relationship between landslides and physical, economic and social variables.
 The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(2), 2019, P 51-56

Use of Simple Geometry to Predict Changes in Coronal and Sagittal Alignments Using an Extramedullary Tibial Cutting Guide During Total Knee Arthroplasty.

During total knee arthroplasty, balancing is necessary for long-term stability and longevity of implants as improper balancing leads to abnormal surface strain. A routine practice among surgeons is to add more posterior slope to the proximal tibia to provide an increase in the flexion gap to balance the knee throughout the entire range of motion, particularly when doing cruciate-retaining knees. The aim of this technique guide is to provide a simple estimate of the posterior slope added or subtracted when cutting the proximal tibia using a standard extramedullary guide. It can also be applied to predict the amount of coronal change instituted using a standard extramedullary drop guide. Using a few basic calculations with a sine equation, a surgeon can accurately predict the amount of change in the slope applied when cutting the proximal tibia. This can be done to control the degree of slope added to the anterior-posterior direction and can be used to predict coronal alignment changes as well. This technique can be applied to any length extramedullary guide and applied across all companies to provide surgeons with an exact degree change in the tibial slope and coronal alignment with simple calculations.

Impacts of soil conservation measures on runoff and soil loss in a hilly region, Northern China

Impacts of soil conservation measures on runoff and soil loss have not been fully considered in the regions where soil erosion control and water resource are both important. In the present study, six years (2014–2019) of runoff and soil loss data from 19 runoff plots in the upstream catchment of the Miyun Reservoir in Beijing, the capital of China were employed to do this work. Results indicated that runoff and soil loss from the plots differed greatly, depending on land use, soil conservation measure and slope degree. Bare and cultivated plots without any soil conservation measures suffered the highest soil loss rate of over 3000 t km−2 yr−1 with higher runoff depth, followed by grass plots (1274.1 t km−2 yr−1), orchard plots (127.2 t km−2 yr−1), and shrub plots (65.3 t km−2 yr−1). H and SLR approached zero on the forest plots. Over 80% of the sediment and runoff were intercepted by shrub, grass, and terraced plots, with SLRs much less than the soil tolerance value (i.e., 200 t km−2 yr−1) in the study region. Contour tillage plots on gentle slope can also intercept over 90% sediment, while allowing most of the generated runoff to run downslope. Implementation of soil conservation measures must be cautious in the study area. Water-saving soil conservation measures should be given priority to in the study region. Contour tillage should be promoted on gentle slopes, and terrace size should be considered on different slopes when it is implemented. The vegetation coverage such as forest, shrub, and grass should be lesser to release more runoff downslope. Soil conservation measures are still required on bare and cultivated slopes. This study can help to implement reasonable soil conservation measures in this and similar regions in the world.

喀斯特山顶区域濒危裸子植物群落特征及其地形关联

PDF HTML阅读 XML下载 导出引用 引用提醒 喀斯特山顶区域濒危裸子植物群落特征及其地形关联 DOI: 10.5846/stxb201904020635 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（41661012）；全国中药资源普查项目（2018-43）；广西重点实验室建设项目（19-185-7） Community characteristics of endangered Gymnosperms and their topographic relationships in a karst mountaintop region Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:喀斯特濒危裸子植物往往局限分布于生境恶劣的山顶区域，受保护的急迫性和必要性较强，但目前针对该区植物群落的研究较少，保护技术措施缺乏理论支持。对木论喀斯特山顶区域典型的濒危裸子植物群落进行了调查，分析了该群落特征的空间变异及其地形关联。结果表明：该群落共有植物73种，隶属于39科58属；裸子植物、双子叶植物、单子叶植物分别有3、67、3种；壳斗科、蔷薇科和樟科物种相对较多；64.1%的科和81.0%的属只含有1个物种。双子叶植物净关系指数（NRI）和最近关系指数（NTI）表现出随机格局。个体数、总基面积、NTI分别在5.66、4.75、6.51 m尺度内具有强烈的空间相关性，空间连续性相对较差；Shannon多样性指数、Simpson多样性指数、Pielou均匀度指数分别在71.01、71.01、42.44 m尺度内具有强烈的空间相关性，空间连续性相对较好。总基面积与凹凸度呈显著正相关关系；濒危裸子植物相对基面积与坡度呈显著正相关关系；NTI与相对海拔呈极显著正相关关系，与坡度和坡向均呈显著负相关关系。上述结果对于喀斯特濒危裸子植物的保护和恢复工作具有一定的指导意义。 Abstract:Most rare and endangered Gymnosperms in karst regions are restricted to mountaintop habitats with inferior conditions and require urgent protection. However, in the literature there is a lack of information about the plant community structure of biotic communities in these ecosystems, which could be used to inform conservation efforts. Here a plant community typical of endangered Gymnosperms in the Mulun karst forest was selected for investigating plant community structure and microtopography. Spatial variability of plant community characteristics was studied using geo-statistical techniques, and the correlations between community characteristics and topographic factors were analysed. The results indicated a complex community structure of 73 species belonging to 39 families and 58 genera, with 3, 67, and 3 species representing Gymnosperms, Dicotyledons, and Monocotyledons, respectively. Dominant families were Fagaceae, Rosaceae and Lauraceae, containing more than five species each. About 64.1% of all families and 81.0% of all genera were represented by only one species. Focussing on Dicotyledoneae, the net relatedness index (NRI) and nearest taxon index (NTI) of this class indicated a random phylogenetic community structure. The individual number, total basal area of all species (BA) and the NTI had strong spatial correlations, at 5.66 m, 4.75 m, and 6.51 m, respectively, showing relatively small ranges of spatial continuity. Shannon's diversity index, Simpson's diversity index, and Pielou's evenness index had strong spatial correlations, at 71.01 m, 71.01 m, and 42.44 m, respectively, showing relatively large ranges of spatial continuity. There were significantly positive correlations between BA and convexity, and between relative basal area of endangered Gymnosperms and slope degree. NTI showed a extremely significant positive correlation with relative elevation, and significantly negative correlations with both slope aspect and slope degree. These results provide useful information for conservation and restoration efforts for endangered Gymnosperm species in karst regions. 参考文献 相似文献 引证文献

The Impact of Felling Method, Bunch Size, Slope Degree and Skidding Area on Productivity and Costs of Skidding in a Eucalyptus Plantation

Grapple skidder is a machine designed for the extraction of tree bunches after felling. Several factors influence its technical performance and costs such as terrain slope, operator experience time, machine type, and the size of tree bunches for each operating cycle, among others. Thus, it becomes necessary to weigh the variables that most influence the productivity and costs of the grapple skidder. So, the main objective was evaluated according to the influence of bunch size using two feller bunchers with distinct technical characteristics, two slope classes and two skidding areas on the productivity and machine production cost in a Eucalyptus plantation. For the analysis of the productivity, the study of time and method was applied and the scheduled machine cost per hour was based on the Food and Agriculture Organization of the United Nations methods. When analyzing the results, it was found that the operational elements moving without load (MWoL) and moving with load (MWL) were the ones that spend the most time in the operational cycle of the grapple skidder. Among the cost components, monetary expenditure on fuel and operator labor were the most influential in the scheduled machine cost per hour. In conclusion, the tree bunches and slope class influenced the productivity and, consequently, the cost of the skidding operation.

Distribution of total carbonate and iron oxides on catena at Duhok Governorate, Kurdistan Region, Iraq

The study area located at Zawita location, Duhok province, Kurdistan region, Iraq. Five pedons were digging on catena depending on the slope degree and slope aspects. Samples were air-dried, ground, and sieved using (2) mm sieve, in order to be used for physicochemical analysis. The soil texture varied from clay loam to sandy loam in the surface horizons of all pedons and became finer from the summit to foot slope in the south aspect, in contrast at the north aspect soil texture became coarser from the summit to foot slope). Study soils were less development and less differentiation of soil horizons in pedons at the summit and back slope in contrast to it at the foot slope of catena and were slightly alkaline non-saline soils. Soil organic matter in the north aspect was more than it in the south aspect. CEC in all horizons for pedon (1) at the summit was high value when compared with it for pedons at the back slope and foot slope. Studied soils consider as calcareous that have a high content of carbonate minerals as a result of the calcification pedogenic process in turn these soils have a high buffering capacity. Total carbonate at the summit, was less amount, in the surface horizon (Ah) then was gradually increased in the subsurface horizon (Bc) after that uniformity increased of carbonate distribution in soil horizons (C1st) and (C2k), whereas was decreased in surface horizons at the back slope at both aspects but in north aspect was less than it at south aspect. In surface horizons, at foot slope in both directions, total carbonate was decreased, whereas the vertical distribution indicated increasing it towards deep horizons of pedons at foot slope. Iron oxides in soil samples were fluctuated between increase and decrease with the exception of pedon (4) at the back slope in the south aspect. Part of the iron oxides was translocation downslope with runoff water and adds it to iron oxides at the foot slope and a considerable amount of it was present in the study location that is causing the change in soil color.

Exploring novel hybrid soft computing models for landslide susceptibility mapping in Son La hydropower reservoir basin

In this study, two novel hybrid models namely Bagging-based Rough Set (BRS) and AdaBoost-based Rough Set (ABRS) were used to generate landslide susceptibility maps of Son La hydropower reservoir basin, Vietnam. In total, 186 past landslide events and twelve landslides affecting factors (slope degree, slope aspect, elevation, curvature, focal flow, river density, rainfall, aquifer, weathering crust, lithology, fault density and road density) were considered in the modeling study. The landslide data was split into training (70%) and testing (30%) for the model’s development and validation. One R feature selection method was used to select and prioritize the landslide affecting factors based on their importance in model prediction. Performance of the hybrid developed models was evaluated and also compared with single rough set (RS) and support vector machine (SVM) models using various standard statistical measures including area under the curve (AUC)-receiver operating characteristics (ROC) curve. The results show that the developed hybrid model BRS (AUC = 0.845) is the most accurate model in comparison to other models (ABRS, SVM and RS) in predicting landslide susceptibility. Therefore, the BRS model can be used as an effective tool in the development of an accurate landslide susceptibility map of the hilly area.

A deformation mode in a cold rolling condition to provide the necessary texture of the Ti-3Al-2.5V alloy

Purpose. Providing deformation conditions in order to obtain the required texture of pipes made of Ti-3Al-2.5V alloy based on the choice of rational values of the tool calibration parameters gauges and mandrels during cold pilger rolling of pipes for the required Q-factor distribution along the deformation cone. Methodology. The research methods were based on the existing dependence, which describes the influence of the distribution of the ratio of true reduction along the deformation cone along the wall thickness and along the average diameter, on the distribution of the Q-factor value. The calculation of calibration and all deformation parameters of the Cold Reducing tube process was based on a number of existing theoretical and empirical dependencies included in the generally accepted and adapted methods of their computation. To perform calculations, we created the software product Q-Factor. Cold pilger tube rolling. Findings. The influence of the initial taper of the mandrel with a curvilinear generatrix and the sweep of the groove ridge, the degrees of steepness of the generatrix of the mandrel and the sweep of the groove ridge, the value of the feed on the distribution of the Q-factor along the compression zones and pre-finishing of the deformation cone were investigated by calculation. The use of slope degrees n, equal to 1.5, i.e. less than values of crest slope degree had the most significant effect on obtaining the Q-factor close to equilibrium distribution along the length of wall reduction and pre-finishing zones. A method of multifactor calibration of the tool for cold pilger rolling of pipes is proposed, which makes it possible to select rational values of the initial taper of the mandrel with a curved generatrix, the degree of slope of the sweep of the groove ridge and the mandrel, and to create conditions in the wall compression zone for obtaining the required type of metal texture of cold-rolled pipes made of titanium alloy Ti-3-2.5V. At the same time, in the prefabrication zone, in all investigated cases, there is a drop in the Q-factor values below one. Originality. New knowledge was obtained about the influence of the rolling route and the full complex of tool calibration parameters in the process of cold pilger rolling of pipes on the distribution of the Q-factor along the length of the deformation cone. Practical value. A method for determining the modes of deformation with an extended compression zone and without a pre-finishing zone is proposed and tested with positive results. This method provides a distribution of the Q-factor along the reduction zone of the deformation cone which is close to uniform distribution and with values above one. The results obtained make it possible to select the conditions for obtaining the required type of metal texture of cold-rolled pipes from titanium alloy Ti-3Al-2.5V using the software product Q-Factor. Cold pilger tube rolling.

Study on Finite Element Numerical Simulation of Rock Slope Based on Ground Penetrating Radar Detection

Weathering degree of natural slope and its mechanical parameters have significant spatio-temporal variability. At present, the method of determining the mechanical parameters according to the suggestions of the specification ignores this phenomenon. In order to improve the accuracy of finite element numerical simulation results, a method for obtaining rock mass mechanical parameters based on ground penetrating radar (GPR) detection was proposed. Based on a rock slope of Xianyang international airport in Shaanxi province, the degree of fracture and water-rich inside the slope were detected by GPR, and the slope was divided into several units with different levels. Then, the mechanical parameters such as elastic modulus, Poisson’s ratio and cohesion force of different units were obtained according to the specification. Fatherly, the finite element numerical simulation software MIDAS-GTS was used to establish the grid model of the slope, and the recommended values provided by the specification were used to calculate the sliding displacement of the slope. Compared with the field displacement monitoring data, the results showed that the numerical simulation values were closer to the monitoring values, indicating that the mechanical parameters obtained by this method were more consistent with the actual value of the rock mass.

Comparison of vegetation patch dynamics after the eruptions of the volcano Mount Usu, northern Japan, in 1977–1978 and 2000, detected by imagery chronosequence

AbstractVegetation patch dynamics were analyzed to detect vegetation development patterns after eruptions on two sites (summit destroyed in 1977–1978, and a foothill, Konpira destroyed in 2000) on the volcano Mount Usu, in northern Japan. Aerial photos and satellite images taken in 2000, 2006, and 2014 were used to develop an imagery chronosequence of vegetation patch dynamics. Vegetation patches were identified by the Normalized Difference Vegetation Index (NDVI) for satellite images, and by the Normalized Green‐Red Difference Index (NGRDI) for aerial photos. We categorized the vegetation patch types based on whether the patches overlapped (touching) or not (isolated) with the future vegetation patches and whether their area increased (growing) or decreased (shrinking). Afterwards, patch dynamics were compared between the two sites through changes in patch types, dense vegetation, and patch growth with slope degree, elevation, and time. Isolated patches were established more at the summit and showed high mortality, while at Konpira most isolated patches survived until 2006 and merged into touching patches by 2014. Moreover, the vegetation density of patches was higher at Konpira than at the summit. Patch growth was associated with patch types at both sites. However, the time was more important for the patch dynamics at the summit, and the vegetation density affected the dynamics more at Konpira. Therefore, the two sites had different vegetation patch dynamics, which were related to the characteristics of topography and eruptions. In conclusion, the imagery chronosequence proposed in this study monitored patch dynamics well, and patches developed faster at Konpira.

Sütçüler yöresi karaçam ormanlarında bitki tür çeşitliliği ve yetişme ortamı ilişkileri

Bu çalışmada Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe meşcerelerinde alfa tür çeşitliliği ve tür zenginliği ile ekolojik ortam koşulları arasındaki ilişkilerin ortaya konulması amaçlanmıştır. Bu amaçla Sütçüler yöresinde yayılış gösteren doğal karaçam meşcerelerinden alınan örnek alanlarda bitki türlerine ait bolluk verileri Braun-Blanquet yöntemine göre kayıt edilerek, 0-1 arasında değişen örtüş-bolluk değerlerine dönüştürülmüştür. Her bir örnek alanda bitki türlerinin yanı sıra yamaç konumu, toprak derinliği, arazi yüzey formu, toprak taşlılığı verileri envanter karnesine kayıt edilmiştir. Yörenin eş yükselti haritasından elde edilen Sayısal Yükseklik Modeli (SYM) yardımıyla çevresel değişkenlerden yükselti, eğim ve bakı haritaları elde edilmiştir. Elde edilen bakı ve eğim haritalarından faydalanılarak, sıcaklık indeksi ve radyasyon indeksi haritaları oluşturulmuştur. Örnek alanlara ait alfa çeşitlilik değerlerinin hesaplanması için Shannon, Brillouin, Simpson ve Berger-Parker indislerinden yararlanılmakla birlikte, ayrıca her bir örnek alan için doğrudan tür zenginliği hesaplaması yapılmıştır. Çalışmada çeşitlilik değerleri ile çevresel değişkenler arasındaki ilişkilerin tespitine yönelik sırasıyla Pearson Korelasyon Analizi ve Temel Bileşenler Analizinden yararlanılmıştır. Uygulanan analizler neticesinde farklı alfa indislerine göre hesaplanan çeşitlilik değerlerinin karaçam ormanlarındaki yükselti ve topraktaki taşlılık oranının artmasıyla birlikte azaldığı, eğim ve sıcaklığın artmasıyla ise arttığı şeklinde bir sonuca varılmıştır. Çalışmada tür zenginliği ile çevresel değişkenler arasında önemli bir ilişki tespit edilemezken, bolluk verilerine dayalı indisler ile hesaplanan çeşitlilik değerlerinin yükselti, sıcaklık, eğim ve toprak taşlılığı değişkenleri ile önemli ilişkileri belirlenmiştir. Bu durum tür çeşitliliği-yetişme ortamı ilişkilerinin ele alındığı çalışmalarda sadece tür zenginliğinin dikkate alınmasının yeterli olmayacağı sonucunu ortaya çıkarmıştır. Ayrıca hesaplamalarda kullanılan farklı alfa çeşitlilik indislerinin çevresel değişkenlerle ilişkilerinin ortaya koyulması aşamasında da kısmi farklılıklar oluşmuştur. Dolayısıyla yapılacak olan çalışmalarda bu durumunda ayrıca göz önünde bulundurulması önem arz etmektedir.

EFFECTS OF ANİMAL GRAZİNG ON FAVORABLE FORAGE YİELD AND QUALİTY OF RANGELANDS WİTH DİFFERENT SLOPE

This study conducted between 2016 and 2017 in the Kosk Village of Yakutiye District of Erzurum Province on rangeland sites with 4 different slopes (0-10%, 10-30%, 30-60 and 60% and above). In the research, current favorable forage yield and some forage quality characteristics of rangeland sites with different slope degrees were investigated. It was determined that the forage yield of rangeland sites decreased in steep slope rangeland sites and increased in slightly sloping rangeland sites. It was determined that the effect of different sloping degrees on some forage quality was important. Slightly slope rangeland sites, forages had higher crude protein content, while steep slope rangeland sites had higher ADF and NDF ratio. Also, it was calculated that the Relative Feed Value (RFV) in the rangelands decreased due to the increase in slope. According to the obtained results, it reveals the necessity to practice appropriate management such as the proper intensity of grazing, especially in sloping areas to ensure sustainable rangeland use.

Studi Pengaruh Derajat Kemiringan Tool Head Terhadap Hasil Pengelasan Friction Stir Welding (FSW)

Aluminum and its alloys are non-ferrous metals which are widely used in the shipping industry because aluminum is a lightweight metal, has a relatively high tensile strength and good corrosion resistance. Friction-stir Welding (FSW) is a welding that is widely used on thin aluminum plates. The heat input of the FSW welding is affected by the degree of tilt of the head tool to the material. This study aims to determine the optimal degree of slope in FSW welding. The parameters used in this study are 1500 rpm rotational speed, 1.33 mm / s welding speed with the same material thickness of 4mm and the type of connection used by lap joint refers to the AWS standard. In this study, the tool head tilt variation is 0o, 1o, 2o and 3o and the effect on the welding results. The results of the study show that welding with a slope angle of 0 ° and 1 shows visible defects or undercut defects caused by overheating when welding. The results of welding with a degree of slope 2 show the results of welding is good at the beginning of welding, but in the middle of welding visible defect undercut. Tilt angle welding shows the best results with no visible defects due to welding. The results showed that visually the results of welding with a slope angle 3 degree had the best results. This was due to the heat input on the welding with the head tool tilt not excessive so there was no visual defect.

Study of the Sediment Transport Law in a Reverse-Slope Section of a Pressurized Pipeline

This article reveals the change law of the head loss and critical deposition velocity during hydraulic transmission of a solid–liquid two-phase pipeline. This article also establishes a physical test model. A single variable is used to conduct the experimental research by changing the conditions of the pipeline flow rate, the sediment concentration, and the reverse slope degree. Based on an analysis of the test process, a new formula is proposed to determine the critical sedimentation rate of the pipeline that considers a change in the adverse slope. By analyzing the variation rule of the hydraulic slope of the pipeline sediment in different states and comparing the hydraulic slope of the horizontal pipeline and reverse pipeline in different states, different factors that influence head loss are revealed. Finally, the measured value of this test is compared with the Durand equation and the Worster equation. It was found that the measured value of this test was more similar to the Durand equation. This study not only provides theoretical support for sand removal in pipelines but also promotes sedimentation in reservoirs.

ÇORUH NEHRİ HAVZASINA BAĞLI OLTU MİKROHAVZASINDA KANAL VE OYUNTU EROZYONUYLA GERÇEKLEŞEN TOPRAK KAYBININ “EROZYON ÇUBUK YÖNTEMİYLE” BELİRLENMESİ

Water erosion is an important erosion type that erodes and transports the most. With the effects of stream water, both streambank and gully erosions cause even more soil transport and debris accumulation resulting more flood events and associated loss of life and properties, as well as increasing the deposition of sediment in dam reservoirs that shorten the economic lifespan of these dams. This study was carried out in 14 different bank erosion sites (stream reach) in the Oltu Micro Catchment (OMC), one of the sub-watershed of the Coruh River Basin, to measure gully and streambank erosions over five-year long study period using “erosion pin method”. Oltu Micro Catchment has arid and semi-arid climate and has a 37% slope degree with a rugged structure. Over the five-year study period, the annual gully and streambank erosion rates were ranged from 1.25 to 8.79 cm/yr and the five-year average was measured as 4.43 cm/yr. The five-year soil losses were ranged from 30.5 to 190.8 tons/km/yr, and the five-year average was measured as 83.9 tons/km/yr. Compared to 1st and 2nd order streams, most of these measured soil losses were due to gully erosion (78%). In addition, it was determined that very large increase in bank erosion was occurred due to increase in rainfall in this semi-arid region showing that these types of watersheds are sensitive to bank erosions. As a conclusion, streambank and gully erosions are dynamic processes effected by the spatial and temporal scale differences under varying climate settings. Additionally, this study is a pioneer one in the region that identifies a need for the conservation practices (particularly for the gullies) to reduce the soil losses and deposited sediment in the whole channel system and eventually in dam reservoirs.