27 research outputs found
Boundary layer transition induced by distributed roughness array
No full textThe effects of a finite, spanwise-periodic array of cylindrical roughness elements on boundary layer transition over a NACA 0012 airfoil are investigated at a chord-based Reynolds number of 1.44×105 by using hotwire anemometry and infrared thermography. Both the number and the spanwise spacing of roughness elements in the array are varied in order to study their effect on the wake flow topology. Spanwise interaction between the roughness elements has an effect on the connection and the merging of neighbouring low-speed regions, which results in the formation of merged low-speed blobs (MLSs) that modify the spatial distribution and the amplitudes of the velocity streaks. When the spanwise distance between adjacent roughness elements equals 1.5 times the cylinder diameter, the transition location moves rapidly upstream. In this case, the two neighbouring low-speed regions overlap with each other in the near wake of the roughness, leading to the maximum growth in the velocity streak amplitude and the velocity fluctuations. The number of roughness elements affects the total number of MLSs within the boundary layer. For a single MLS behind a pair of cylinders, the Kelvin-Helmholtz instability dominates the growth of velocity fluctuations around the three-dimensional shear layers. When three cylinders are placed in the array, two MLSs appear in the near wake, which coalesce in to one low-speed blob downstream before the onset of transition, revealing the importance of Kelvin-Helmholtz instability.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Wind Energ
Effect of Surface Roughness Geometry on Boundary-Layer Transition and Far-Field Noise
No full textSurface roughness elements are often used to force laminar to turbulent transition in aerodynamic and aeroacoustic wind-tunnel experiments. The statistical features and spectral content of the pressure fluctuations in the resulting turbulent boundary layer at the trailing edge can affect far-field noise. To elucidate this dependence, boundary-layer transition induced by randomly distributed roughness elements and a zigzag strip of the same height over a NACA 0012 airfoil is investigated experimentally. The effects of roughness geometry on the near-field flow topology, transition location, and far-field noise are addressed in the common experimental setting for the first time. For a fixed roughness height, distributed roughness elements are less effective in forcing transition than the zigzag strip at low freestream velocity (u∞<20 m/s). As u∞ increases, the transition front for the distributed roughness elements moves closer to the roughness location, reaching the same or even further upstream locations compared to the transition onset in the presence of the zigzag strip. The far-field noise depends on the transition location. For u∞≤20 m/s, a higher noise level is measured for the distributed roughness elements with respect to the zigzag strip. In contrast, for u∞>20 m/s, the earlier onset of transition with the distributed surface roughness leads to a lower noise level than that with the zigzag strip. The data confirm that an adequate characterization of the boundary-layer transition is necessary when measuring the far-field noise during wind-tunnel experiments.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Wind Energ
Nitrogen metabolism and transport in the Arbuscular mycorrhizal interaction
No full textThe Arbuscular Mycorrhiza is arguably the world's most important interaction. The roots of over 70 % of all known land plant species form this mutualistic interaction with fungi of the phylum Glomeromycota. Arbuscular mycorrhizal (AM) fungi can act as biofertilizers, bioprotectors and bioregulators of plants and have gained increasing attention for their potential role in sustainable agriculture and in the restoration and bioremediation of contaminated and disturbed sites. In this interaction plants take up mineral nutrients from the soil through their associated AM fungi and transfer in exchange for their beneificial effect on nutrient uptake photosynthetically fixed carbon to the fungus. Nitrogen (N) is known to be transferred from the fungus to the plant in the AM interaction, yet its metabolism, storage and transport in the symbiosis are poorly understood. Here, we report new findings about the N metabolism and transport in the AM symbiosis by analyzing fungal gene expression with quantitative polymerase chain reaction (Q-PCR).
In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in two-compartment Petri dishes. Different experiments were carried out to measure the effect of different carbon (C) or nitrogen (N) sources on fungal gene expression. The RNA was extracted from the ERM and processed for Q-PCR using gene specific primers. Inorganic nitrogen is taken up by the fungus with its extraradical mycelium (ERM), is incorporated into amino acids, and translocated from the ERM to the intraradical mycelium (IRM) as arginine, where it is broken down to an inorganic form via the catabolic arm of the urea cycle and transferred to the plant without C (Govindarajulu et al., 2005; Jin et al., 2005). Consistent with the proposed mechanism, the genes involved primarily in nitrogen assimilation were highly expressed in the ERM whereas the mRNA transcripts levels of genes associated with the breakdown of arginine were low in the ERM. The expression levels of these genes are regulated by the C availability for the mycorrhizal fungus and by an exogenous supply of N to the ERM.M.S.Includes bibliographical references (p. 34-38)by Sulbha Choudhar
Variation in thyroid hormone concentration in brain microdialysates from freely-moving adult rats
No full textThyroid hormone has genomic and non-genomic actions in the developing and mature human. The focus of this research was to find if there was a measurable amount of thyroid hormone in the extracellular fluid of the adult rat brain and how it varied over time. To study the levels of thyroid hormone concentration in the adult brain, stereotaxic surgery was performed to implant a microdialysis cannula and electrodes for the study of electroencephalogram (EEG), electromyogram (EMG). The stylet blocking the microdialysis cannula was removed and the probe was inserted at the beginning of the study for sample collection. EEG and EMG waves were recorded concurrently. Artificial cerebrospinal fluid (aCSF) was run through the inlet tube of the probe and sample was obtained from the outlet using a refrigerated fraction collector. Collected samples were analyzed by high pressure liquid chromatography (HPLC), liquid chromatography mass spectrometry (LC/MS) and radioimmunoassay (RIA) for presence of the thyroid hormone. Samples run through the C18 column on the HPLC gave a peak for thyroid hormone at a retention time of 4.1minutes. Similar results were generated when the microdialysate samples were analyzed using LC/MS. The LC of the microdialysate gave the peak at the retention time of 4.1 minutes. This peak was further studied for confirmation by MS ionization. MS gave a fragmentation pattern which corresponded to the breakdown products of the thyroid hormone. The RIA kit with thyroid hormone standards prepared in aCSF was used for the detection of the thyroid hormone concentration. The level of thyroid hormone in samples varies over time. The variation in thyroid hormone level over time was compared to the sleep data obtained concurrently. The variation seen in the thyroid hormone concentration over time was detected by HPLC, LC/MS and RIA. This variation suggests some possibility of a mechanism of release of thyroid hormone in adult brain. This finding would be consistent with the potential signaling role of TH suggested by earlier experiments performed in our lab.M.S.Includes bibliographical references (p. 51-56)by Namrata Choudhar
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Exploring Bela, in Gujarat, India
No full textThis video explores the 3D laser scanning data obtained in Bela, a historic village located in Gujarat, India in 2021. This is part of the AHRC and DCMS funded project: 'A sustainable re-construction method for seismic-prone heritage areas of India based on advanced recording technologies'. In this project, we are using advanced recording technologies and social surveys to develop a sustainable re-construction method for seismic-prone heritage settlements of Gujarat. Capturing the built environment using 3D-laser-scanning-also known as LiDAR-gives an accurate, fast and comprehensive digital data set, measurable and coloured 3D point-cloud with a precision of millimetres, which has been combined with inhabitant’s interviews. This enhanced digital model of the case study, the village of Bela, offers a basis for damage assessments, improving the chances of a rapid and effective response in case of an earthquake, as well as offering a technical platform for risk mitigation measures and community engagement, aiming to increase resilience. The methodology is scalable and applicable to other identified heritage settlements in Gujarat, India. HOW TO CITE: © 3D for Heritage India NTU. 2021-2022. www.3D4heritageindia.wordpress.com Author: Dr Bernadette Devilat (NTU) using the 3D data processed by Dr Felipe Lanuza and obtained on-site by Mrudula Mane and Zeus Pithawalla (CHC CRDF), supported by Dr Jigna Desai from CHC CRDF; Aditya Singh and Tanvi Choudhari from the Hunnarshala Foundation; and Sukrit Sen from ICCROM
An observational study of Consideration of Anguli Pramana in view of the Health Status in the present era
Get PDFIntroduction: Anguli pramana is an age-old technique of human body measurements stated in Ayurveda. Acharyas have mentioned Anguli pramana for various parts of the body. The study aimed at its validation in the present era on the basis of health status. There are so many factors related to the health status of individual. Hence, the present study aimed at health status wise consideration of Anguli pramana. Method: With prior ethical permission, 770 healthy participants of both gender between age group 18-50 years in Ahmednagar and Nashik region were selected. Measurements were taken for selected body parts. The middle finger width of the right hand at proximal interphalangeal joint was used as a unit for Anguli pramana. Collected data analyzed using the student’s t test for inference. Result: On comparison of measured values for selected parameters and the standard values stated by acharya in both genders found statistically different except for few parameters i.e., Pad parinah, Pad vistar and Prakoshṭha ayam. Discussion: The study shows variations in values obtained by Anguli pramana. This could be due to evolutionary changes and lifestyle of a human being. Though the findings are applicable to the selected sample size and selected parameters, the study could further be extended as this is a non-invasive ancient method of anthropometry. Revision of all the values for the present era will definitely serve as an alternative method for prediction of health of human being
An Observational Study to Assess the Validity of Anguli Pramana in the Present Era
Get PDFIntroduction: The concept of Anguli pramana is one of the hypothetical concepts in Ayurved put forth by acharyas. It mainly deals with the measurements of various parts of the human body. After reviewing the previous research done, it was noticed that, not a single study was being carried out by anyone of the researchers for assessing the validity of Anguli pramana in the present era. Therefore, the present study was planned. Method: After ethical clearance, the study was conducted. In total 770 participants of age group 18-50 years from Ahmednagar and Nashik region were selected. Measurements were taken for selected parameters, recorded and converted into Swa-anguli pramana. Swa-anguli pramana was measured by taking width of the middle finger at the proximal interphalangeal joint of right hand. All the measurements were taken following Standard Operating Procedure. The data was analyzed with the test of Normality, Z score using Systat 13.0 version software. Result: In the present study, obtained value and standard value stated by Acharya Charaka for the selected parameters were compared and found statistically different. Similarly, obtained value and standard value stated by Acharya Sushruta for the selected parameters were compared and found statistically different. Discussion: The results were negative i.e., non comparable with the standard values stated by acharas for the selected parameters. It was observed that the Anguli pramana mentioned in ancient literature may not be considered valid in the present era. It may be because of evolutionary changes and lifestyle changes of the human being
A Systematic Review: Standard Measurement method of Anguli pramana
Get PDFIntroduction: Anguli pramana is an ancient form of anthropometric measurements where individual’s own finger width is used as a unit of measurement. Different researchers had attempted to standardize the Anguli pramana. This systematic review aims to review all the available published literature and to provide the narrative summary on Anguli pramana. Methods: References were sought in Google scholar, AYUSH Research portal, DHARA online, Pub med, Shodhganga, eShodhSindhu datasets and other sources like Grey literature by utilizing all the keywords and MeSH terminologies. Following PRISMA guidelines, 32 full-text eligible papers were assessed and 9 articles extracted for study design, population parameters, methodology, evaluation system, outcome and other relevant findings. Result: 5 out of 9 studies have reconfirmed that breadth of middle finger (BM) of right hand proved as more accurate method of measurement in Anguli pramana while in 3 studies average of right and left middle finger at proximal interphalangeal joint is used as a method of measurement. Only 1 study shows use of average of breadth of four fingers at metacarpophalangeal joints of right and left hand as a method of measurement. Discussion: Present systematic review concludes that breadth of middle finger of the right hand at proximal interphalangeal joint (BM) is the standard method of measurement for Anguli pramana
Study of Anguli Pramana in individuals with different nutritional status with respect to its validity in the present era
Get PDFIntroduction: Anguli Pramana is an ancient form of Anthropometry put forth by sages. It mainly deals with the measurements of the human body. Literature search revealed that, not a single study was being carried out for assessing the validity of Anguli Pramana in the present era. Therefore, the present study was planned. Method: After ethical clearance, 770 participants between 18-50 years were selected from Ahmednagar and Nashik region. Measurements were taken for selected parameters and converted into Swa-Anguli Pramana. Body Mass Index of each participant was calculated and categorized according to the nutritional status. The data analyzed with Student’s t-test using Systat 13.0 version software. Result: Comparative data of standard and measured value was found statistically different in all nutritional status groups. Discussion: Anguli Pramana may not be considered valid in the present era may be due to evolutionary changes and lifestyle changes in the human being
Gender wise consideration of Anguli Pramana in the present era
Get PDFIntroduction: Anguli pramana is a unique concept in Ayurved. It was stated by acharyas at times when there was no any sort of standardised unit of measurements. Acharyas have mentioned Anguli pramana for various parts of the body. In respect of male and female gender, no separate anthropometric values found to be mentioned. Hence, the present study aimed at gender wise consideration of Anguli pramana. Method: After seeking ethical permission, 770 healthy participants of both gender between age group 18-50 years in Ahmednagar and Nashik region were selected for the study. Measurements were taken for selected body parts. The middle finger width of the right hand at proximal interphalangeal joint was used as a unit for Anguli pramana. Collected data treated with the Student’s t test for inference. Result: Measured values for selected parameters when compared with the standard values stated by acharya in both genders found statistically different except for a few i.e., Pad parinah and Pad vistar. Discussion: Variations in Anguli pramana may be due to evolutionary changes and lifestyle in the present era. The present study concluded that Anguli pramana is not valid in the present era. Its validity was checked according to gender separately. Though the findings are confined to the selected sample size and selected parameters, it could further be extended to arrive at generalization
