12 research outputs found
Behavior of Mono Helical Pile Foundation in Clays under Combined Uplift and Lateral Loading Conditions
No full textOffshore wind energy development is driven by ongoing research and development to determine technological issues connected with offshore wind turbines. A fundamental design difficulty is the offshore wind turbine foundations. By far, one of the most commonly practiced foundation systems is mono helical pile foundations because of their simplicity and resilience. Most of the studies on mono helical piles were focused on granular soils and few studies were on clayey soils. However, mono helical piles in clayey soils under combined loading remain to be examined. Hence, a series of three-dimensional finite element analyses were carried out to predict the uplift and lateral capacity of the helical pile embedded in soft clay. The numerical model is verified using the results from the analytical results and a small-scale laboratory test. The verified model is used to simulate the helical pile behavior under the combined uplift and lateral loading condition considering the pile with a different number of helical plates. The results of the combined loading analyses reveal that the lateral capacity decreased when the pile was subjected to uplift load, and a maximum reduction of 12% is observed in mono helical piles provided with a single plate for an applied 50% of the ultimate uplift load. The influence of uplift load also increased the bending moment of the helical pile. Finally, it is suggested that the helical piles should be designed considering the aspects for combined loading conditions
Influence of fibres on volume change attributes of expansive soil blended with lime
No full text Expansive soils are considered to be highly problematic due to their dual swell–shrink behaviour. In recent years, polymeric fibres are used to control the volume change behaviour of expansive soils. In this study, different proportions of lime and fibres were used to study the swelling and shrinkage behaviour of expansive soils. The test results showed that swelling tended to decrease slightly with an increase in the fibre content, whereas shrinkage decreased significantly with the addition of fibres. The optimum fibre content was found to be 2%. Both swelling and shrinkage tended to decrease significantly with increasing the lime content. It was also found that the optimum lime content is different for controlling swelling and shrinkage. Therefore, expansive soil specimens blended with 2% fibre and with varying lime contents were tested. The addition of 2% fibre helped to reduce the content of lime required for controlling shrinkage. It was found that blending 2% fibres and 5% lime together in expansive soils is effective for controlling both swelling and shrinkage behaviour. </jats:p
Statistical Optimization of Blending Conditions and Performance Evaluation of Optimal Bio-Asphalt Content
No full textTo mitigate environmental impacts and promote sustainability in highway construction, this study investigates the optimization of blending conditions and the performance evaluation of bio-modified asphalt binder incorporating bio-asphalt derived from the pyrolysis of waste cooking oil (WCO) and low-density polyethylene (LDPE). A response surface approach was employed to optimize key blending parameters—temperature, speed, and time—based on critical physical properties of the binder. Furthermore, the optimized bio-asphalt binder was further evaluated through rheological performance tests (multiple stress creep recovery and linear amplitude sweep) and mechanical performance tests (Marshall stability, tensile strength ratio, resilient modulus, indirect tensile fatigue, and dynamic creep). The optimal conditions were identified as 130°C, 1000 rpm, and 42.37 min. Statistical validation using ANOVA, residual analysis, leverage, and Cook’s distance confirmed the model’s reliability, with prediction errors remaining below 5%. The bio-modified asphalt binder exhibited enhanced elastic recovery and reduced non-recoverable creep compliance (Jnr), indicating superior resistance to permanent deformation in comparison with the control asphalt binder. Additionally, the bio-modified asphalt mixture demonstrates superior Marshall stability, resilient modulus, tensile strength ratio, retained stability, and resistance to deformation in comparison with the control asphalt binder. These results demonstrate the potential of bio-asphalt as a viable, eco-friendly modifier for asphalt binders in tropical climates
Endorrhizal fungal symbiosis in aroids of the Western Ghats, southern India
No full textInformation of dark septate endophyte (DSE), arbuscular mycorrhizal (AM), and fine root endophyte (FRE) fungal symbioses of aroids in the Western Ghats region are very low. Therefore, we assessed the endorrhizal symbiosis in 25 aroid species belonging to 16 genera of Araceae from six different locations of the Western Ghats. The results revealed co-occurrence of the DSE and AM symbiosis in all the examined aroids, and FRE presence in seven aroids (Alocasia ´ amazonica, Alocasia sp., Anthurium andraeanum, Epipremnum aureum, Spathiphyllum sp., Syngonium podophyllum, and Zantedeschia aethiopica). We found variance in root length having AM (inter and intracellular hyphae, arbuscules, vesicles and arbusculate coils) and DSE (melanized septate hyphae, microsclerotia, and moniliform hyphae) fungal structures. Moreover, the AM fungal morphology of Arum-Paris type was widespread, and intermediate type morphology reported for the first time in five aroids. AM fungi colonized the roots of Philodendron xanadu the most, followed by DSE in Caladium bicolor, and FRE in Spathiphyllum sp. AM fungal spores were present in all aroid soils examined. The percentage of root length comprising FRE hyphae was significantly and positively correlated root length with FRE arbuscules, AM fungal spore numbers and total colonization. Our study revealed that, the aroids tend to form associations with various endorrhizal fungi.
Vegetative anatomy and mycorrhizal morphology of Schoenorchis nivea (Lindl.) Schltr., (Orchidaceae) and their adaptive significance
No full textThe anatomical description of the vegetative parts (leaf, leaf sheath, stem and root) and mycorrhizal morphology of Schoenorchis nivea (Lindl.) Schltr., belonging to the subfamily Epidendroideae of Orchidaceae was investigated. Leaves were amphistomatic covered by 10-12 µm thick cuticle, stomata paracytic with small and irregular substomatal chambers. Mesophyll homogenous, composed of thin-walled chlorenchymatous cells. Banded water-storage cells abundant in the mesophyll and the largest vascular bundle occurred at the centre of the leaf. The leaf sheath has both adaxial and abaxial epidermis covered with cuticle, homogenous mesophyll, water-storage cells, raphides and vascular bundles. The stem is surrounded by a uniseriate epidermis, cortex consisting of thick-walled fibers and collateral vascular bundles scattered in the ground tissue. Cortical proliferation was evident in S. nivea stem. Root hairs present in root regions were in contact with the substratum. Root hairs frequently branched at their tips. Root possess 2-3 layered velamen, ∩-thickened exodermal cells, O-thickened uniseriate endodermis, and cortex of thin-walled parenchymatous cells containing raphides and water-storage cells. Cover cells present. Xylem arches are 9-11, with vascular tissues embedded in sclerenchymatous cells. Pith composed of thick-walled sclerenchymatous cells with intercellular space. The stomatal characteristics in leaf, the size of water-storage cells and vascular bundles exhibited significant variation in different plant parts. Intact and degenerating pelotons of orchid mycorrhizal fungi were observed in the root cortical cells. The observations of the present study clearly indicate that S. nivea possesses several anatomical adaptations to thrive in epiphytic habitats
Asociación de hongos endofíticos en raíces de plantas medicinales exóticas cultivadas en Nilgiris, Western Ghats, India Peninsular: Asociación de hongos de raíz en plantas medicinales exóticas
No full textSome soil beneficial microbes help in the establishment and growth of exotic medicinal plants. Therefore, we evaluated the presence and status of root endophyte [arbuscular mycorrhizal (AM) fungi and dark septate endophytic (DSE) fungi] association in ten exotic medicinal plant species cultivated in the Nilgiris of the Western Ghats. The AM fungi colonized all the examined plant species and eight plants had the co-occurrence of DSE fungi. The extent of fungal endophyte variables and root hair characteristics significantly differed among the medicinal plants. Six AM fungal spore morphotypes were identified in the soil samples. Thus, this study indicated the association of exotic medicinal plants with native AM and DSE fungi which could be exploited to promote growth and increase secondary metabolite production in these plant species. Algunos microbios beneficiosos para el suelo ayudan en el establecimiento y crecimiento de plantas medicinales exóticas. Por lo tanto, evaluamos la presencia y el estado de la asociación de endófitos de raíces [hongos micorrízicos arbusculares (AM) y hongos endofíticos septados oscuros (DSE)] en diez especies de plantas medicinales exóticas cultivadas en Nilgiris de los Ghats occidentales. El alcance de las variables endófitas de hongos y las características del pelo de la raíz difirieron significativamente entre las plantas medicinales. Se identificaron seis morfotipos de esporas de hongos AM en las muestras de suelo. Por lo tanto, este estudio indicó la asociación de plantas medicinales exóticas con hongos nativos AM y DSE que podrían explotarse para promover el crecimiento y aumentar la producción de metabolitos secundarios en estas especies de plantas
Asociación de hongos endofíticos en raíces de plantas medicinales exóticas cultivadas en Nilgiris (Western Ghats, India Peninsular)
No full textAlgunos microbios beneficiosos del suelo ayudan al establecimiento y crecimiento de plantas medicinales exóticas. Evaluamos la
presencia y el estado de la asociación de endófitos de raíces
[hongos micorrízicos arbusculares (AM) y hongos endofíticos septados oscuros (DSE)] en diez especies de plantas medicinales
exóticas cultivadas en Nilgiris (Ghats Occidentales). Los hongos
AM colonizaron todas las especies examinadas y ocho plantas tuvieron la co-ocurrencia de hongos DSE. El alcance de las variables
de los hongos endofíticos y las características del pelo radicular difirieron significativamente entre las plantas. Se identificaron seis
morfotipos de esporas de hongos AM. Por lo tanto, este estudio
indicó la asociación de plantas medicinales exóticas con hongos
nativos AM y DSE que podrían explotarse para promover el crecimiento y aumentar la producción de metabolitos secundarios en
estas especies de plantas.Some soil beneficial microbes help in the establishment and growth
of exotic medicinal plants. We evaluated the presence and status
of root endophyte [arbuscular mycorrhizal (AM) fungi and dark
septate endophytic (DSE) fungi] association in ten exotic medicinal
plant species cultivated in the Nilgiris (Western Ghats). The AM
fungi colonized all the examined plant species, and eight plants
had the co-occurrence of DSE fungi. The extent of fungal
endophyte variables and root hair characteristics significantly
differed among the plants. Six AM fungal spore morphotypes were
identified. Thus, this study indicated the association of exotic
medicinal plants with native AM and DSE fungi which could be
exploited to promote growth and increase secondary metabolite
production in these plant species
