Literatura académica sobre el tema "Root Area Ratio (RAR)"

The number of roots and root area ratio (RAR) decreased with depth in Acacia mangium and Macaranga tanarius and the maximum value of RAR and root number were observed in the first layer of soil. This process was regular in Acacia mangium Willd., but the RAR value showed great variability in Macaranga tanarius L. as the RAR decreased with depth until the second layer (20 cm) and increased again. About 35% of all roots in A. mangium, and about 50% of all roots in M. tanarius are located in the first layer. About 87% of all roots were in the fine root diameter class (d < 2 mm) in M. tanarius species. However 90% of all roots were in the fine root diameter class in A. magnium species. Fine roots contribution to soil reinforcement due to concentration on upper levels, prevent surface erosion and shallow landslide. These results will be useful for slope stability projects. DOI: http://dx.doi.org/10.3329/bjb.v43i2.21665 Bangladesh J. Bot. 43(2): 141-145, 2014 (September)

Plant roots play a key role in stabilizing slopes, particularly in the Mediterranean region, characterized by rough and unstable terrain. However, forest species differ in their stabilizing capacities. The purpose of this study is to fill the gap of knowledge on root biomechanical properties of relevant Mediterranean trees and shrubs in relation to slope stability. Root specimens of typical montane Mediterranean tree and shrub species were sampled in Southern Italy. Root characteristics, such as tensile strength (Tr) and root area ratio (RAR), were assessed from live roots sampled in trenches, while root cohesion was calculated. Power law functions yielded the best fit for the relationship of Tr versus root diameter; however, no significant relationship was found between root strength and root moisture content. RAR varied amongst different tree and shrub species. Roots of Quercus cerris L. were the most resistant to breaking under tension, while roots of Ilex aquifolium L. had the highest tensile strength among all shrub species. Results provide quantitative information on the role of root systems of montane Mediterranean forest species in stabilizing soils and will improve modeling of landslide susceptibility to the prevention and mitigation of natural hazards in mountain environments.

Abstract. The present paper deals with the characteristics of the root system of Spanish Broom (Spartium junceum L.), a species that is worth taking into consideration for its capacity for adaptation and resistance to drought. In particular, the aims of the study were 1) to investigate the plant's bio-mechanical aspects and 2) to verify whether root reinforcement and the field rooting ability of stem cuttings enhance its potential for use in slope stabilization and soil bio-engineering techniques, particularly in Mediterranean areas. Single root specimens were sampled and tested for tensile strength, obtaining classical tensile strength-diameter relationships. Analyses were performed on the root systems in order to assess root density distribution. The Root Area Ratio (RAR) was analyzed by taking both direct and indirect measurements, the latter relying on image processing. The data obtained were used to analyze the stability of an artificial slope (landfill) and root reinforcement. The measurement and calculation of mean root number, mean root diameter, RAR, root cohesion and Factor of safety are presented in order to distinguish the effect of plant origin and propagation. Furthermore, tests were performed to assess the possibility of agamic propagation (survival rate of root-ball endowed plants, rooting from stem cuttings). These tests confirmed that agamic propagation is difficult, even though roots were produced from some buried stems, and for practical purposes it has to be ruled out. Our results show that Spanish Broom has good bio-mechanical characteristics with regard to slope stabilization, even in critical pedoclimatic conditions and where inclinations are quite steep, and it is effective on soil depths of up to about 50 cm, in agreement with other studies on Mediterranean species. It is effective in slope stabilization, but less suitable for soil bio-engineering or for triggering natural plant succession.

Abstract. The present paper deals with the root system's characteristics of Spanish Broom (Spartium junceum L.), a species whose capacity for adaptating and resisting to drought is worth investigating. In particular, the aims of the study were 1) to investigate the plant's bio-mechanical aspects and 2) to verify whether root reinforcement and the field rooting ability of stem cuttings enhance its potential for use in slope stabilization and soil bio-engineering techniques, particularly in the Mediterranean areas. Single root specimens were sampled and tested for tensile strength, obtaining classic tensile strength-diameter relationships. Analysis were performed on the root systems in order to assess root density distribution. The Root Area Ratio (RAR) was analyzed by taking both direct and indirect measurements, the latter relying on image processing. The data obtained were used to analyze the stability of an artificial slope (landfill) and the root reinforcement. The measurement and calculation of mean root number, mean root diameter, RAR, root cohesion and Factor of safety are presented in order to distinguish the effect of plant origin and propagation. Furthermore, tests were performed to assess the possibility of agamic propagation (survival rate of root-ball endowed plants, rooting from stem cuttings). These tests confirmed that agamic propagation is difficult, even though roots were produced from some buried stems, and for practical purposes it has been ruled out. Our results show that Spanish Broom has good bio-mechanical characteristics with regard to slope stabilization, even in critical pedoclimatic conditions and where inclinations are quite steep, and it is effective on soil depths up to about 50 cm, in agreement with other studies on Mediterranean species. It is effective in slope stabilization, but less suitable for soil bio-engineering or for triggering natural plant succession.

At present, the root soil interface bonding is not considered in the root system of mechanical soil-fixing model. The typical restoration plant Amorpha fruticosa, utilizing the widely used Wu model (WWM), the tensile and tensile properties of single root, and the shear strength properties of root soil composite tailing, is analyzed by the tensile tests of plant roots, pullout tests, and shear tests based on the effect of interfacial bond strength; based on the failure mode of root system in root soil, the modified WWM model is used to calculate the increment of shear strength of composite tailing soil. The results showed that ① the relationship between root diameter of A. fruticosa and tensile strength was power function. ② The bond between root and soil becomes more tight, and the pullout strength of the root system increases significantly. ③ When root soil area ratio (RAR) is the same, shear deformation capacity of root soil composite tailing soil increases with the increase of interface bonding strength. Under the condition of the same interface bonding strength, the cohesion of root soil composite tailing soil is greater than that of tailing soil and increases with the increase of RAR, but the change of internal friction angle is not significant. When the pullout strength is added to the plant root prediction model, the soil consolidation effect of the plant root system can be better reflected. The range of the revised coefficient of the WWM model for the root soil composite tailing soil is 0.15~0.37. The research results will provide a theoretical basis and data support for quantifying the ecological restoration and reinforcement capacity of tailing pond shrubs and plants, slope stability, soil and water management, and other ecological soil consolidation capacity of mines.

The degree of mechanical reinforcement provided by plants depends upon its roots distribution in the soil and mechanical properties of the roots. The mechanical properties and distribution of root traits (root diameter and number) in the soil of the standing forest depends on the tree stem diameter. This variation of root traits with tree stem diameter is rarely investigated. Therefore, this research presents the effect of tree stem diameter on the distribution of roots within the standing forest of Cunninghamia in the Longchi forest area, Sichuan province, China. In this area, shallow landslides take place frequently. We investigated the root traits distribution for trees with different stem diameters, i.e., 220 mm, 320 mm, 450 mm, and 468 mm, to show the variation of roots distribution in the soil with stem diameter. The root architecture of the selected trees was studied by step excavation method of the root zone accompanied by measurement of roots physical parameters (roots number and roots diameter) and indices (roots area ratio (RAR), roots biomass (RB), and roots distribution (RD)). We measured the root’s maximum tensile strength by performing root tensile tests in the laboratory. The field and laboratory-measured data were used to estimate the root cohesion by both the commonly used model Wu and Waldron Model (WWM) and Fiber Bundle Model (FBM). The results indicate that the tree stem diameter correlates with both the root distribution and the tensile strength. The roots indices and root cohesion increase with an increase in the diameter of the tree. Further, RAR decreases with depth and lateral distance from the tree stem, while the maximum values were observed in 10 cm depth. The relationship between roots diameter and roots tensile strength is established through power function. The average root cohesion estimated for a tree with stem diameter 220 mm is 23 kPa, 29 kPa for 320 mm, 54 kPa for 450 mm, and 63 kPa for 460 mm. This effect of stem diameter on the increase of soil shear resistance should be considered while evaluating the stability of slopes in standing forests. The comparison between WWM and FBM for investigated species suggests that WWM estimates the cohesion values greater than FBM by 65%.

Floods and subsequent bank erosion are recurring hazards that pose threats to people and can cause damage to buildings and infrastructure. While numerous approaches exist on modeling bank erosion, very few consider the stabilizing effects of vegetation (i.e., roots) for hydraulic bank erosion at catchment scale. Taking root reinforcement into account enables the assessment of the efficiency of vegetation to decrease hydraulic bank erosion rates and thus improve risk management strategies along forested channels. A new framework (BankforNET) was developed to model hydraulic bank erosion that considers the mechanical effects of roots and randomness in the Shields entrainment parameter to calculate probabilistic scenario-based erosion events. The one-dimensional, probabilistic model uses the empirical excess shear stress equation where bank erodibility parameters are randomly updated from an empirical distribution based on data found in the literature. The mechanical effects of roots are implemented by considering the root area ratio (RAR) affecting the material dependent critical shear stress. The framework was validated for the Selwyn/Waikirikiri River catchment in New Zealand, the Thur River catchment and the Sulzigraben catchment, both in Switzerland. Modeled bank erosion deviates from the observed bank erosion between 7% and 19%. A sensitivity analysis based on data of vertically stable river reaches also suggests that the mechanical effects of roots can reduce hydraulic bank erosion up to 100% for channels with widths < 15.00 m, longitudinal slopes < 0.05 m m−1 and a RAR of 1% to 2%. The results show that hydraulic bank erosion can be significantly decreased by the presence of roots under certain conditions and its contribution can be quantified considering different conditions of channel geometry, forest structure and discharge scenarios.

The soil–water characteristic curve is an important tool to evaluate the water-holding capacity of unsaturated soil. Plant roots can affect the matric suction of soil and the water-holding capacity and permeability of the soil. Therefore, the morphological characteristics of plant roots will lead to the difference in soil–water characteristics between soil slope and plant-covered slope. This study aims to investigate the effect of Vetiver root morphology on soil–water characteristic curves of plant-covered slope soil. The hydrological effect of the root distribution on the root–soil system was also discussed. The results showed that: (1) The root surface area index (RAI) and root volume ratio (Rv) of each soil section of the vetiver root system varied with depth in accordance with the Gaussian function distribution; (2) In the process of natural drying, the matric suction generated within the root system is significantly higher than that generated by evaporation of bare soil in the same soil layer. The ability of vegetation soil to enhance soil matrix suction increases with the increase of soil root surface area index; and (3) The α and n values of the SWCC model decreased with the increase of Rv (root volume ratio of soil), while the air entry value increased. Under the same water content, the matric suction corresponding to vegetation soil is significantly greater than bare soil. In addition, the soil–water characteristic curve can be effectively predicted by combining the Rv of vegetated soils.

We generated high-quality shallow landslide susceptibility maps for Bijar County, Kurdistan Province, Iran, using Random Forest (RAF), an ensemble computational intelligence method and three meta classifiers—Bagging (BA, BA-RAF), Random Subspace (RS, RS-RAF), and Rotation Forest (RF, RF-RAF). Modeling and validation were done on 111 shallow landslide locations using 20 conditioning factors tested by the Information Gain Ratio (IGR) technique. We assessed model performance with statistically based indexes, including sensitivity, specificity, accuracy, kappa, root mean square error (RMSE), and area under the receiver operatic characteristic curve (AUC). All four machine learning models that we tested yielded excellent goodness-of-fit and prediction accuracy, but the RF-RAF ensemble model (AUC = 0.936) outperformed the BA-RAF, RS-RAF (AUC = 0.907), and RAF (AUC = 0.812) models. The results also show that the Random Forest model significantly improved the predictive capability of the RAF-based classifier and, therefore, can be considered as a useful and an effective tool in regional shallow landslide susceptibility mapping.

AbstractThis research aims to know the oil palm seedling growth response in the main nursery toward N-P-K (12-0,6-6) fertilizer with the trademark Vedagro with different doses. The research was carried out in the Paal Merah Lama village, Southern Jambi sub district, started from 16 September until 16 Desember 2015. The research design used was Completely Randomized Design, with fertilizer dose of Vedagro as a treatment which consists of 6 levels, namely: d0 (control), d1 (5 g polybag-1), d2 (10 g polybag-1), d3 (15 g polybag-1), d4 (20 g polybag-1) and d5 (25 g polybag-1), using 4 replicates. The observed variables a plant height, totally plant leaf area, plant dry weight, and shoot-root ratio. The material used is oil palm seedlings aged 3 mounths. Data were analyzed using analysis of varians, then continued by Duncan test (DNMRT) at the 5% level. The results showed that giving real effect against the Vedagro fertilizer to plant height, totally plant leaf area, plant dry weight, and shoot-root ratio. 20 g dose of Vedagro fertilizer, showed the best effect on seeds height and dry weight, while the best effect on shoot-root ratio and totally plant leaf area was in 15 g dose.Keywords; the growth of plants, fertilizer application AbstrakPenelitian ini bertujuan untuk mengetahui respon pertumbuhan bibit kelapa sawit di pembibitan utama terhadap pemberian pupuk N-P-K (12-0,6-6) (merek dagang Vedagro) dengan dosis yang berbeda. Penelitian dilaksanakan di kelurahan Paal Merah Lama kecamatan Jambi Selatan, mulai 16 September sampai 16 Desember 2015. Rancangan yang digunakan adalah Rancangan Acak Lengkap (RAL), yaitu dosis pupuk Vedagro yang terdiri dari 6 level yaitu, d0 (kontrol), d1 (5 g polybag-1), d2 (10 g polybag-1), d3 (15 g polybag-1), d4 (20 g polybag-1) dan d5 (25 g polybag-1), dengan 4 ulangan. Peubah yang diamati adalah tinggi tanaman, luas daun total, berat kering tanaman dan nisbah tajuk akar. Bahan yang digunakan adalah bibit kelapa sawit berumur 3 bulan. Analisis data menggunakan analisis ragam dan dilanjutkan dengan uji Duncan (DNMRT) pada taraf α 5 %. Hasil penelitian menunjukkan bahwa pemberian pupuk Vedagro berpengaruh nyata terhadap tinggi bibit, luas daun total, berat kering tanaman dan nisbah tajuk akar. Pemberian pupuk Vedagro dengan dosis 20 g polybag-1 memperlihatkan pengaruh terbaik terhadap tinggi bibit dan berat kering bibit, sedangkan dosis 15 g polybag-1 menghasilkan pengaruh terbaik pada nisbah tajuk akar dan luas daun total. Kata kunci ; pertumbuhan tanaman, aplikasi pupuk

Forests can prevent and/or mitigate hydrogeomorphic hazards in mountainous landscapes. Their effect is particularly relevant in the case of shallow landslides phenomena, where plants decrease the water content of the soil and increase its mechanical strength. Although such an effect is well known from ages, its quantification is a relatively new challenge. The present dissertation faces the effect on hillslope stability of several forest species typical of Lombardy’s mountain forests. Such effects are estimate in terms of additional root cohesion by the classical Wu (1976) and Waldron (1977) model (W&W) and by Fiber Bundle Model approach (FBM). Samples of European beech (Fagus sylvatica L.), Norway spruce (Picea abies (L.) Karst.), European larch (Larix decidua Mill.), sweet chestnut (Castanea sativa Mill.) and European hop-hornbeam (Ostrya carpinifolia Scop.), Sycamore Maple (Acer pseudoplatanus L.), Grey Alder or Speckled Alder (Alnus incana (L.) Moench), European Ash (Fraxinus excelsior L.), Manna Ash (Fraxinus ornus L.), Black Locust (Robinia pseudoacacia L.), were taken in different locations of Lombardy (Northern Italy) to estimate root tensile strength, Root Area Ratio the root cohesion distribution within the soil. Besides the increasing of knowledge concerning the ability of the mentioned species to reinforce soils, that are fundamental to estimate the stability of forested hillslopes in the Alps, the dissertation reaches some more general results. Referring to root tensile strength, the obtained results confirm that such property is related to root size by a power law relationship. Such relationship, however, is not invariant with species but shows dependence with site’s characteristics, although the observed variability is very high and no specific factor has been resulted as a key factor. Considering roots with a diameter greater than 1 mm, European beech roots seem to be more resistant than Norway spruce, Sweet chestnut and European Ash. Referring to Root Area Ratio, the results herein presented showed a great variability within the same species at the same location and among different locations. Despite the number of rooted profiles investigated, such variability hindered the possibility to identify a specie-specific or site-specific behaviour. Concerning root cohesion modelling, the original W&W model seems to overestimate root reinforcement because it assumes that all the roots crossing the shear surface break at the same time. FBM approach, instead, accounting for the progressive breaking of roots represents a promising perspective in root cohesion evaluation. Root cohesion values present the same species and site variability according to RAR values. The values herein obtained, moreover, are consistent with the results of direct shear tests and back-analysis data and, finally, they are significant for slope stabilisation at depth where shallow landslides generally occur.

The aim of this thesis is to develop indirect and non-invasive methodologies for the tree root distribution analysis, with a multidisciplinary approach. Slope stability study needs the quantification of the root distribution. Current techniques carries out direct measurements on the root system by digging, uprooting and other invasive, non-replicable and onerous techniques. The methodologies, applied in this study, come from geophysics (I) and biomechanics (II). With the first approach, the geoelectric method is applied, in order to quantify the soil resistivity, in relation to water content. By this methodology a electrical resistivity tomography of a soil profile is obtained, which has been elaborated to evaluate the variation of the resistivity in relation to the presence of plant roots. With the second approach, controlled pulling tests on trees of different sizes and different species are performed, in order to build a new mathematical model for assessing the safety factor of a plant, subject to an external force such as wind. Thanks to the model, it is possible to evaluate the root system effect, in terms of stabilizing moment, depending on the soil characteristics. The results obtained show that both methodologies are able to provide important information about the root distribution of plants. In addition, the techniques and models developed with this study can provide innovative tools in other areas of research, for example for assessing plant stability and developing innovative bioengineering works.

Plant functional traits (plant height, aboveground biomass, R/S ratio, specific leaf area, leaf dry matter content, specific root length and arbuscular mycorrhizal infection) were measured for several grassland plant species growing under different soil fertility conditions in a greenhouse and a field experiments. Traits` response to nutrient addition and the differences in traits among species and between forbs and grasses were studied. Results from the greenhouse and the field experiment were compared.

The aim of the paper was to determine the influence of root systems of chosen tree species found in the Polish Flysch Carpathians on the increase of soil shear strength (root cohesion) in terms of slope stability. The paper's goal was achieved through comprehensive tests on root systems of eight relatively common in the Polish Flysch Carpathians tree species. The tests that were carried out included field work, laboratory work and analytical calculations. As part of the field work, the root area ratio (A IA) of the roots was determined using the method of profiling the walls of the trench at a distance of about 1.0 m from the tree trunk. The width of the. trenches was about 1.0 m, and their depth depended on the ground conditions and ranged from 0.6 to 1.0 m below the ground level. After preparing the walls of the trench, the profile was divided into vertical layers with a height of 0.1 m, within which root diameters were measured. Roots with diameters from 1 to 10 mm were taken into consideration in root area ratio calculations in accordance with the generally accepted methodology for this type of tests. These measurements were made in Biegnik (silver fir), Ropica Polska (silver birch, black locust) and Szymbark (silver birch, European beech, European hornbeam, silver fir, sycamore maple, Scots pine, European spruce) located near Gorlice (The Low Beskids) in areas with unplanned forest management. In case of each tested tree species the samples of roots were taken, transported to the laboratory and then saturated with water for at least one day. Before testing the samples were obtained from the water and stretched in a. tensile testing machine in order to determine their tensile strength and flexibility. In general, over 2200 root samples were tested. The results of tests on root area ratio of root systems and their tensile strength were used to determine the value of increase in shear strength of the soils, called root cohesion. To this purpose a classic Wu-Waldron calculation model was used as well as two types of bundle models, the so called static model (Fiber Bundle Model — FIRM, FBM2, FBM3) and the deformation model (Root Bundle Model— RBM1, RBM2, mRBM1) that differ in terms of the assumptions concerning the way the tensile force is distributed to the roots as well as the range of parameters taken into account during calculations. The stability analysis of 8 landslides in forest areas of Cicikowicleie and Wignickie Foothills was a form of verification of relevance of the obtained calculation results. The results of tests on root area ratio in the profile showed that, as expected, the number of roots in the soil profile and their ApIA values are very variable. It was shown that the values of the root area ratio of the tested tree species with a diameter 1-10 ram are a maximum of 0.8% close to the surface of the ground and they decrease along with the depth reaching the values at least one order of magnitude lower than close to the surface at the depth 0.5-1.0 m below the ground level. Average values of the root area ratio within the soil profile were from 0.05 to 0.13% adequately for Scots pine and European beech. The measured values of the root area ratio are relatively low in relation to the values of this parameter given in literature, which is probably connected with great cohesiveness of the soils and the fact that there were a lot of rock fragments in the soil, where the tests were carried out. Calculation results of the Gale-Grigal function indicate that a distribution of roots in the soil profile is similar for the tested species, apart from the silver fir from Bie§nik and European hornbeam. Considering the number of roots, their distribution in the soil profile and the root area ratio it appears that — considering slope stability — the root systems of European beech and black locust are the most optimal, which coincides with tests results given in literature. The results of tensile strength tests showed that the roots of the tested tree species have different tensile strength. The roots of European beech and European hornbeam had high tensile strength, whereas the roots of conifers and silver birch in deciduous trees — low. The analysis of test results also showed that the roots of the studied tree species are characterized by high variability of mechanical properties. The values Of shear strength increase are mainly related to the number and size (diameter) of the roots in the soil profile as well as their tensile strength and pullout resistance, although they can also result from the used calculation method (calculation model). The tests showed that the distribution of roots in the soil and their tensile strength are characterized by large variability, which allows the conclusion that using typical geotechnical calculations, which take into consideration the role of root systems is exposed to a high risk of overestimating their influence on the soil reinforcement. hence, while determining or assuming the increase in shear strength of soil reinforced with roots (root cohesion) for design calculations, a conservative (careful) approach that includes the most unfavourable values of this parameter should be used. Tests showed that the values of shear strength increase of the soil reinforced with roots calculated using Wu-Waldron model in extreme cases are three times higher than the values calculated using bundle models. In general, the most conservative calculation results of the shear strength increase were obtained using deformation bundle models: RBM2 (RBMw) or mRBM1. RBM2 model considers the variability of strength characteristics of soils described by Weibull survival function and in most cases gives the lowest values of the shear strength increase, which usually constitute 50% of the values of shear strength increase determined using classic Wu-Waldron model. Whereas the second model (mRBM1.) considers averaged values of roots strength parameters as well as the possibility that two main mechanism of destruction of a root bundle - rupture and pulling out - can occur at the same. time. The values of shear strength increase calculated using this model were the lowest in case of beech and hornbeam roots, which had high tensile strength. It indicates that in the surface part of the profile (down to 0.2 m below the ground level), primarily in case of deciduous trees, the main mechanism of failure of the root bundle will be pulling out. However, this model requires the knowledge of a much greater number of geometrical parameters of roots and geotechnical parameters of soil, and additionally it is very sensitive to input data. Therefore, it seems practical to use the RBM2 model to assess the influence of roots on the soil shear strength increase, and in order to obtain safe results of calculations in the surface part of the profile, the Weibull shape coefficient equal to 1.0 can be assumed. On the other hand, the Wu-Waldron model can be used for the initial assessment of the shear strength increase of soil reinforced with roots in the situation, where the deformation properties of the root system and its interaction with the soil are not considered, although the values of the shear strength increase calculated using this model should be corrected and reduced by half. Test results indicate that in terms of slope stability the root systems of beech and hornbeam have the most favourable properties - their maximum effect of soil reinforcement in the profile to the depth of 0.5 m does not usually exceed 30 kPa, and to the depth of 1 m - 20 kPa. The root systems of conifers have the least impact on the slope reinforcement, usually increasing the soil shear strength by less than 5 kPa. These values coincide to a large extent with the range of shear strength increase obtained from the direct shear test as well as results of stability analysis given in literature and carried out as part of this work. The analysis of the literature indicates that the methods of measuring tree's root systems as well as their interpretation are very different, which often limits the possibilities of comparing test results. This indicates the need to systematize this type of tests and for this purpose a root distribution model (RDM) can be used, which can be integrated with any deformation bundle model (RBM). A combination of these two calculation models allows the range of soil reinforcement around trees to be determined and this information might be used in practice, while planning bioengineering procedures in areas exposed to surface mass movements. The functionality of this solution can be increased by considering the dynamics of plant develop¬ment in the calculations. This, however, requires conducting this type of research in order to obtain more data.

Abstract The popular perception of prehistoric buildings, a simple-ring roundhouse with central post, is represented in later Bronze Age settlements, surviving occasionally into the Iron Age. But the classic Wessex large roundhouses are characterized by double rings that commonly display axial symmetry in plan and a particular radial ratio that distributes the weight of the roof over the main supporting ring-beam. Where the outer wall does not survive, a mass-wall or stake-wall may be inferred, often aligned on the inner of a double pair of door posts. Apart from hearths, internal fittings seldom survive, except in wetland conditions, as at Black Loch of Myrton, Wigtownshire. An alternative elevation of large timber roundhouses may have been built around a central tower, circular or four-post, with split roof and clerestory light. Multi-ringed houses are comparatively rare, and may indicate an alternative form of roof, made of turf, at a lower pitch. Houses formerly styled ‘ring-ditch houses’ may have confused several different phenomena. They may have been byre-houses, houses with underfloor cellarage or proto-souterrains, or houses with sunken floors for increased peripheral head height. ‘Special roundhouses’ are discussed as those in which community ritual was prioritized over domestic activities.

This chapter considers how media landscapes in the home have shifted over this century and examines how devices relate to each other and to householders to create dynamic and evolving media ecologies. At the turn of this century, a typical domestic media ecology comprised a cathode-ray television in the living room, perhaps connected to a videocassette recorder; a desktop computer in a home office, perhaps connected to a dial-up modem; and a landline telephone, often located in a communal area in the home. More recently, the home has become a place for high-definition “smart” televisions, intelligent multifunction set-top boxes, game consoles, digital radio, high-speed broadband, cabled and wireless home networks, mobile computing, cloud connections, online government service provision, gesture-controlled games, and much more. How and why have these technologies been appropriated? How has this ongoing appropriation reconfigured the domestic media ecology and the life that is lived within this ecology?

Tropical cloud forests play a fundamental role in the hydrological cycle of mountain watersheds having the largest biodiversity per unit area. In Venezuela, cloud forests are subject to intense deforestation and fragmentation by farming and cattle-ranching causing soil erosion, water cycle alteration, and biodiversity loss. Reforestation projects used exotic species as Pines and Eucalyptus, native species were rarely planted by lacking knowledge on species requirements and management. We report the performance of 25 native cloud forest species differing in shade-tolerance, planted in mixed assemblies on degraded areas. Tree survival and the individual tree variables: total height, root-collar diameter, tree-slenderness, and crown-ratio were evaluated at 1, 2, 4.5 and 7 years-old. Data was analyzed with a repeated measures analysis of variance mixed model considering species shade-tolerance, light intensity at planting and age as explanatory factors. Survival was over 80%. Shade-intolerant species displayed faster height and root-collar diameter growth. Shade-tolerant species had larger crown ratios due to persistence of lower branches; whereas, shade-intolerant showed signs of crown recession at age 7. Slenderness values from age 4.5 were indicative of good trees stability and health across treatments. The positive results have motivated landowners to establish native species plantations in critical areas with our support.

This chapter deals with image processing in the specific area of image zooming via interpolation. The authors employ bivariate rational cubic ball function defined on rectangular meshes. These bivariate spline have six free parameters that can be used to alter the shape of the surface without needed to change the data. It also can be used to refine the resolution of the image. In order to cater the image zomming, they propose an efficient algorithm by including image downscaling and upscaling procedures. To measure the effectiveness of the proposed scheme, they compare the performance based on the value of peak signal-to-noise ratio (PSNR) and root mean square error (RMSE). Comparison with existing schemes such as nearest neighbour (NN), bilinear (BL), bicubic (BC), bicubic Hermite (BH), and existing scheme Karim and Saaban (KS) have been made in detail. From all numerical results, the proposed scheme gave higher PSNR value and smaller RMSE value for all tested images.

This chapter deals with image processing in the specific area of image zooming via interpolation. The authors employ bivariate rational cubic ball function defined on rectangular meshes. These bivariate spline have six free parameters that can be used to alter the shape of the surface without needed to change the data. It also can be used to refine the resolution of the image. In order to cater the image zomming, they propose an efficient algorithm by including image downscaling and upscaling procedures. To measure the effectiveness of the proposed scheme, they compare the performance based on the value of peak signal-to-noise ratio (PSNR) and root mean square error (RMSE). Comparison with existing schemes such as nearest neighbour (NN), bilinear (BL), bicubic (BC), bicubic Hermite (BH), and existing scheme Karim and Saaban (KS) have been made in detail. From all numerical results, the proposed scheme gave higher PSNR value and smaller RMSE value for all tested images.

Ned Wayburn was born in Pittsburgh, Pennsylvania, 30 March 1874, and raised in Chicago. He studied at the Hart Conway Chicago School of Elocution while working as an engineer for the family business, Weyburn (sic) Machinery Co. There, he was trained in military drills and in ‘harmonic Gymnastics’, by a second-generation Delsarte teacher: Ida Simpson-Serven. He worked in vaudeville as a pianist, while developing dance acts with integrated lighting effects. Moving to New York, he gained a reputation with Feature Acts. Among his 300+ dance direction and stage direction credits are three groups of shows to which he brought innovations: plotted musical comedies with Lew Fields for and about contemporary 1911–14 businessman audiences, topical revues, especially with Florenz Ziegfeld, Jr., and roof garden revues. He was equally famous for developing individual specialties for performers in vaudeville and on Broadway. Wayburn ran a New York studio and Home-Study Course, which he advertised as delivering ‘Health, Beauty and Independence’ to prospective women students. In the 1920s, he added radio production and training and was experimenting with television revues just before his death in 1942.

From a remote outpost of global warming, a summons crackles over a two-way radio several times a week: . . . Kathmandu, Tsho Rolpa! Babar Mahal, Tsho Rolpa! Kathmandu, Tsho Rolpa! Babar Mahal, Tsho Rolpa! . . . In a little brick building on the lip of a frigid gray lake fifteen thousand feet above sea level, Ram Bahadur Khadka tries to rouse someone at Nepal’s Department of Hydrology and Meteorology in the Babar Mahal district of Kathmandu far below. When he finally succeeds and a voice crackles back to him, he reads off a series of measurements: lake levels, amounts of precipitation. A father and a farmer, Ram Bahadur is up here at this frigid outpost because the world is getting warmer. He and two colleagues rotate duty; usually two of them live here at any given time, in unkempt bachelor quarters near the roof of the world. Mount Everest is three valleys to the east, only about twenty miles as the crow flies. The Tibetan plateau is just over the mountains to the north. The men stay for four months at a stretch before walking down several days to reach a road and board a bus to go home and visit their families. For the past six years each has received five thousand rupees per month from the government—about $70—for his labors. The cold, murky lake some fifty yards away from the post used to be solid ice. Called Tsho Rolpa, it’s at the bottom of the Trakarding Glacier on the border between Tibet and Nepal. The Trakarding has been receding since at least 1960, leaving the lake at its foot. It’s retreating about 200 feet each year. Tsho Rolpa was once just a pond atop the glacier. Now it’s half a kilometer wide and three and a half kilometers long; upward of a hundred million cubic meters of icy water are trapped behind a heap of rock the glacier deposited as it flowed down and then retreated. The Netherlands helped Nepal carve out a trench through that heap of rock to allow some of the lake’s water to drain into the Rolwaling River.

Conceptual design is the first and most important phase of an aircraft’s configuration and system development process. That being said, there is no denying that innovation in aviation has stunted over the last 50 years; the once every present fascination of flying has been blanketed by the rapid profit-driven commercializing of an industry. Moreover, we have reached an apex of maximizing the efficiency of current passenger aircraft model configurations. In recent times, new research and development has culminated to the introduction of aerodynamic structures to address key issues such as stability and fuel efficiency. This research paper seeks to push the envelope of innovation with a brand new perspective on how we view air travel — redefining the Why, What and How. It explores novel concepts such as Boeing Blended Wing Body (BWB) aircraft shown in, which does not follow the conventional Tube and Wing (TAW) configuration. It is a tailless design that integrates the wing and the fuselage into a single-lifting surface. The most common advantages include a higher lift-to-drag ratio and higher payload capacity due to a distribute load along the centerline of the aircraft. On the other hand, a tailless configuration comes at a cost to in-flight maneuvering and stability. The unique design of the Hybrid-MCX-1 aircraft involves the application of the active aero-elastic tailoring to aircraft topology optimization for both subsonic and transonic regimes. With a focus on experimental wind tunnel testing and high-fidelity simulations, this project proposes a new concept that deviates from today’s tubular and wing concept. The aircraft has a unique shape with a forward fuselage that starts off with the conventional tubular and winged aircraft design currently flown in commercial travel, but deviates to a wider cross section at the center of the fuselage. The model has self-supporting, cantilever, dihedral, swept wings, with pronounced fillets at the junction of the wing root and fuselage, blending them smoothly. This smooth transition reduce interference between airflow over the wing root and the adjacent body surface, ultimately reducing drag. The engines of the Hybrid-MCX-1 are mounted by at 45-degree angle on the rear of the plane. This engine location offers the opportunity for swallowing the boundary layer of air from that portion of the center body upstream of the inlet, providing improved propulsive efficiency by reducing the ram drag. The Hybrid-MCX-1 also possesses a vertical tail that bisects the engines. As with current commercial aircraft, this tail provides lateral stability and controls the yaw. In the case of the BWB, yaw control is made possible by sweeping the wing and downloading the wingtips. However, this approach reduces the effective aerodynamic wingspan of the aircraft and imposes a significant induced drag penalty. The presence of a tail on the concept model addresses the aforementioned issue and rectifies unwanted yawing that may arise during cross wind flight conditions. The rear end of the aircraft decrease significantly in vertical thickness when compared to the lateral thickness to minimize the possibility of flow separation as air passes around the wings and over the front half of the aircraft while maximizing total lifting surface area. The pylons are adequately sized to avoid aerodynamic interference between fuselage, pylon and nacelle but still relatively short to minimize drag.

The root strengthening effects on soil behind retaining walls may be quantified by a simplified equation ΔS = 1.2TR(AR/A) where ΔS, TR and AR/A are the shear strength increase, tensile strength of root and root area ratio respectively. However, this effect is ignored during stability analysis due to the possible significant variability of the potential beneficial effect and extreme difficulty in fully characterizing the tree roots and quantifying their effects. In this paper, advancements in the last few decades in biotechnical slope stability are reviewed. Representative models to quantify the mechanical effects of tree roots are studied. If other potential beneficial effects due to existence of roots and suction effect due to transpiration of tree are ignored, the term 1.2, root tensile strength and root area ratio may still be the three key parameters to the root strengthening effect in slope stability.

The paper derives an expression for the effective opening area of a uniform stress process zone at fracture initiation. The expression relates this area to the area that is appropriate to the idealized case of a semi-infinite crack in an infinite solid, and is a two term expansion in terms of the ratio of the square root of this area to a characteristic structural dimension.

This paper proposes a structural mathematical model of heat exchange into the soil of a solarium. The model investigates the possibility of a rational choice of the cooling water transit time through the pipeline network located in the plant root area. Also, the size of the cooled root area is roughly determined, according to the temperature of the cooling fluid. At the same time, the model provides information on the degree of soil cooling, meaning the ratio between the average soil temperature in the cooled root area and a reference temperature, for example the temperature indicated by a sensor into the soil, at a distance fixed to the root axis. The model considered is a plan one. Geometric is considered a section through the soil, perpendicular to the axis of the pipe carrying the cooling fluid. The soil, the copper pipe and the water are the components of the model. The finite elements for meshing are flat, triangular. This simple model prepares a three-dimensional complex approach and has, as a preparation, a unidimensional model. Obviously, this model provides some start-up indications for achieving the physical model and content of the process parameter set. After its realization, the physical model will be used for the optimal control of the cooling process in the radicular area, but also for the validation and the improvement of the theoretical model.

In this work, several different bioinspired filter geometries are proposed, fabricated, and tested in a flow tank. A novel approach is explored that mimics how filter-feeding fish efficiently remove small food particles from water. These filters generally take the form of a cone with water entering the large end of the cone and exiting through mesh-covered slots in the side of the cone, which emulates the rib structure of these filter-feeding fish. The flow in and around the filters is characterized and their ability to collect algae-scale, neutrally-buoyant particles is evaluated. Filter performance is evaluated by using image processing to count the number of particles collected and studying how the particles are deposited on the filter. Results are presented in the form of particle collection efficiencies, which is a ratio of particles collected to the particles that would nominally enter the filter inlet, and images of the fluorescent particles deposited on the filter at different time intervals. The results show little sensitivity to the filters’ inlet geometries, which was the major difference between filters tested. Comparative results are also presented from a 2D CFD model of the filters generated in COMSOL. The different geometries may differentiate themselves more at larger Reynolds numbers, and it is believed that a fluid exit ratio, or ratio of inlet area to exit area, is the most critical filter parameter. Field testing has demonstrated collection of real algae (i) with this bioinspired filter, and (ii) from a robot platform, but using a more conventional plankton net. The larger vision is to develop these filters and mount them on a swarm of autonomous surface vehicles, i.e. a robot boat swarm, which is being developed in parallel.

Gears with an internal gearing are more exploited today for their indisputable advantages. This contribution deals with some of the rare problems in designing these gears: - internal gearing with a small number difference between teeth, even if this difference is zero; - application of High Contact Ratio (HCR) gearing for an internal gearing; - solution of problems related to restriction given by the root spacewidth of a designed ring gear.

The vertical dynamics of half car models riding on irregular road surfaces is characterized by base excitations with time delays determined by the ratio of the car speed and the axle distance between front and rear wheels. Root mean square values of the stationary car vibrations are analytically investigated to derive closed-form results by means of symbolic programming software packages. In particular, the paper discusses modelling aspects when noise filtering and time-delay shifts are interchanged in order to obtain more simple calculations in the frequency domain and in the time domain, as well.

In order to improve the performance of the upstream pumping mechanical seal, and considering one specific spiral groove upstream pumping mechanical seal, an improvement project about the groove structure on the seal surface is put forward. The slipping mesh technique was adopted to simulate the internal flow. After simulation, the pressure pulsation at different monitor points are compared and analyzed, and BVF (boundary vortex flow) diagnosis method is used to analyze the results, which is to explore the relationship between groove type and sealing performance. The results shows that the groove root with fillet compared to acute angle can improve the effect of dynamic pressure at the root of groove and increase static pressure in high pressure area. But overlarge round radius will weaken the pumping effect of spiral groove and increase vortex flow. It can also increase flow loss at groove root area, which will reduce of opening force of liquid film and increase the amplitude of pressure pulsation that affect the stability of the sealing performance. Hence, an optimum radius groove length ratio Rr exists, which can acquire the largest sealing performance and good stability, and this can provide reference to improve the upstream pumping mechanical seal performance.

This paper summarizes experimental and computational results on the mixing of opposed rows of jets with a confined subsonic crossflow in rectangular ducts. The studies from which these results were excerpted investigated flow and geometric variations typical of the complex 3-D flowfield in the combustion chambers in gas turbine engines. The principal observation was that the momentum-flux ratio, J, and the orifice spacing, S/H, were the most significant flow and geometric variables. Jet penetration was critical, and penetration decreased as either momentum-flux ratio or orifice spacing decreased. It also appeared that jet penetration remained similar with variations in orifice size, shape, spacing, and momentum-flux ratio when the orifice spacing was inversely proportional to the square-root of the momentum-flux ratio. It was also seen that planar averages must be considered in context with the distributions. Note also that the mass-flow ratios and the orifices investigated were often very large (jet-to-mainstream mass-flow ratio >1 and the ratio of orifices-area-to-mainstream-cross-sectional-area up to 0.5 respectively), and the axial planes of interest were often just downstream of the orifice trailing edge. Three-dimensional flow was a key part of efficient mixing and was observed for all configurations.

Abstract In order to explore the similarities and differences between the flow fields of cantilever stator and idealized compressor cascade with tip clearance, and to extend the cascade leakage model to compressors, the influence of stator hub rotation to represent cascade and cantilever stator on hub leakage flow was numerically studied. On this basis, the control strategy and mechanism of blade root suction were discussed. The results show that there is no obvious influence on stall margin of the compressor whether the stator hub is rotating or stationary. For rotating stator hub, the overall efficiency is decreased while the total pressure ratio is increased. At peak efficiency point and near stall point, the efficiency is reduced by about 0.43% and 0.34% individually, while the total pressure ratio is enlarged by about 0.23% and 0.27%, respectively. The gap leakage flow is promoted due to stator hub rotation, and the structure of the leakage vortex is weakened obviously. In addition, the hub leakage flow originating from the blade leading edge of rotating hub may contribute to double leakage near the trailing edge of the adjacent blade. However, the leakage flow directly out of the blade passage with stationary stator hub. The stator root loading and strength of the leakage flow increase with the rotation of the hub, and the leakage vortex is further away from the suction surface of the blade and is stretched to an ellipse closer to the endwall under the shear action. The rotating hub makes the flow loss near the stator gap increase, while the flow loss in the upper part of the blade root is decreased. Meanwhile, the total pressure ratio in the end area is increased. Blade root suction of cantilever stator can effectively control the hub leakage flow, inhibit the development of hub leakage vortex, and improve the flow capacity of the passage, thereby reducing the flow loss and modifying the flow field in the end zone.

Background Transplanting vegetable seedlings to final spacing in the greenhouse is common practice. At the time of transplanting, the transpiring leaf area is a small fraction of the ground area and its cooling effect is rather limited. A preliminary modeling study suggested that if water supply from root to canopy is not limiting, a sparse crop could maintain about the same canopy temperature as a mature crop, at the expense of a considerably higher transpiration flux per leaf (and root) area. The objectives of this project were (1) to test the predictions of the model, (2) to select suitable cooling methods, and (3) to compare the drought resistance of differently prepared seedlings. Procedure Plants were grown in several configurations in high heat load environments, which were moderated by various environmental control methods. The difference between the three experimental locations was mainly in terms of scale, age of plants, and environmental control. Young potted plants were tested for a few days in small growth chambers at Technion and Newe Ya'ar. At NCSU, tomato plants of different ages and planting densities were compared over a whole growing season under conditions similar to commercial greenhouses. Results Effect of spacing: Densely spaced plants transpired less per plant and more per unit ground area than sparsely spaced plants. The canopy temperature of the densely spaced plants was lower. Air temperature was lower and humidity higher in the compartments with the densely spaced plants. The difference between species is mainly in the canopy-to-air Bowen ratio, which is positive for pepper and negative for tomato. Effect of cooling methods: Ventilation and evaporative pad cooling were found to be effective and synergitic. Air mixing turned out to be very ineffective, indicating that the canopy-to-air transfer coefficient is not the limiting factor in the ventilation process. Shading and misting, both affecting the leaf temperature directly, proved to be very effective canopy cooling methods. However, in view of their side effects, they should only be considered as emergency measures. On-line measures of stress: Chlorophyll fluorescence was shown to accurately predict photosynthesis. This is potentially useful as a rapid, non-contact way of assessing canopy heat stress. Normalized canopy temperature and transpiration rate were shown to correlate with water stress. Drought resistance of seedlings: Comparison between normal seedlings and partially defoliated ones, all subjected to prolonged drought, indicated that removing about half of the lowermost leaves prior to transplanting, may facilitate adjustment to the more stressful conditions in the greenhouse. Implications The results of this experimental study may lead to: (1) An improved model for a sparse canopy in a greenhouse. (2) A better ventilation design procedure utilizing improved estimates of the evaporation coefficient for different species and plant configurations. (3) A test for the stress resistance of transplants.