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Cilia-assisted hydromagnetic pumping of biorheological couple stress fluids

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Propulsion and Power Research 2019年第3期8卷 221-233页

作者： K.ramesh D.tripathi O.Anwar Bég Department of Mathematics Symbiosis Institute of TechnologySymbiosis International UniversityPune412115India Department of Mechanical Engineering Manipal University JaipurRajasthan303007India Fluid Mechanics/Propulsion Aeronautical/Mechanical Engineering DepartmentSalford UniversityManchesterUK

A theoretical study is conducted for magnetohydrodynamic pumping of electroconductive couple stress physiological liquids(***)through a two-dimensional ciliated channel.A geometric model is employed for the cilia which are distributed at equal intervals and produce a whip-like motion under fluid interaction which obeys an elliptic trajectory.A metachronal wave is mobilized by the synchronous beating of cilia and the direction of wave propagation is parallel to the direction of fluid flow.A transverse static magnetic field is imposed transverse to the channel *** Stokes’couple stress(polar)rheological model is utilized to characterize the *** normalized two-dimensional conservation equations for mass,longitudinal and transverse momentum are reduced with lubrication approximations(long wavelength and low Reynolds number assumptions)and feature a fourth order linear derivative in axial velocity representing couple stress contribution.A coordinate transformation is employed to map the unsteady problem from the wave laboratory frame to a steady problem in the wave *** slip conditions are imposed at the channel *** emerging linearized boundary value problem is solved analytically and expressions presented for axial(longitudinal)velocity,volumetric flow rate,shear stress function and pressure *** flow is effectively controlled by three geometric parameters,viz cilia eccentricity parameter,wave number and cilia length and two physical parameters,namely magnetohydrodynamic(MHD)body force parameter and couple stress non-Newtonian *** solutions are numerically evaluated with MATLAB *** velocity is observed to be enhanced in the core region with greater wave number whereas it is suppressed markedly with increasing cilia length,couple stress and magnetic parameters,with significant flattening of profiles with the latter two *** pressure gradient is decreased with eccentricity parameter whereas it is ele

关键词： Magneto hydrodynamics Metachronal waves Cilia Synchronous beating Polar couple stress fluid Physiological transport Magnetic blood pumps

Field cancerisation in colorectal cancer:A new frontier or pastures past?

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World Journal of Gastroenterology 2015年第13期21卷 3763-3772页

作者： Abhilasha Patel Gyanendra tripathi Kishore Gopalakrishnan Nigel Williams ramesh P Arasaradnam Department of Colorectal Surgery University Hospitals of Coventry and Warwickshire NHS TrustCoventry CV2 2DXUnited Kingdom University of Warwick Coventry CV4 7ALUnited Kingdom Department of Pathology University Hospitals of Coventry and Warwickshire NHS TrustCoventry CV2 2DXUnited Kingdom

Despite considerable advances in our understanding of cancer biology, early diagnosis of colorectal cancer remains elusive. Based on the adenoma-carcinoma sequence, cancer develops through the progressive accumulation of mutations in key genes that regulate cell growth. However, recent mathematical modelling suggests that some of these genetic events occur prior to the development of any discernible histological abnormality. Cells acquire pro-tumourigenic mutations that are not able to produce morphological change but predispose to cancer formation. These cells can grow to form large patches of mucosa from which a cancer arises. This process has been termed "field cancerisation". It has received little attention in the scientific literature until recently. Several studies have now demonstrated cellular, genetic and epigenetic alterations in the macroscopically normal mucosa of colorectal cancer patients. In some reports, these changes were effectively utilised to identify patients with a neoplastic lesion suggesting potential application in the clinical setting. In this article, we present the scientific evidence to support field cancerisation in colorectal cancer and discuss important limitations that require further investigation. Characterisation of the field defect is necessary to enable early diagnosis of colorectal cancer and identify molecular targets for chemoprevention. Field cancerisation offers a promising prospect for experimental cancer research and has potential to improve patient outcomes in the clinical setting.

关键词： Colorectal cancer Carcinogenesis Biomarkers Epigen

Microstructure and texture evolution in AZ31 magnesium alloy during caliber rolling at different temperatures

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Journal of Magnesium and Alloys 2017年第3期5卷 340-347页

作者： Abhishek tripathi S.V.S.Narayana Murty P.ramesh Narayanan Department of Metallurgical Engineering and Materials Science Indian Institute of Technology BombayMumbai 400076India Materials Characterisation Division Materials and Metallurgy GroupVikram Sarabhai Space CentreTrivandrum 695022India

Magnesium alloy AZ31 was caliber rolled at different temperatures viz.523K,573K,623K,673K and 723K imposing a total cumulative reduction of 92%and a cumulative strain of *** associated microstructure and texture evolution were studied using Electron Back Scattered Diffraction(EBSD)and X-ray macro-texture observations *** refinement was observed in all the caliber rolled bars indicating the occurrence of dynamic *** parameter and texture index were used to study the evolution of *** doubling of the yield strength at room temperature was observed by caliber rolling at a temperature of *** improvement in mechanical properties was explained on the basis of the fine grain microstructures and suitable development of crystallographic *** on the present study,warm caliber rolling can be used as a good production method for obtaining long bars of high strength magnesium alloy AZ31.

关键词： Magnesium alloy AZ31 Microstructure Caliber rolling Texture

Optimizing Tillage and Irrigation Requirements of Sorghum in Sorghum-Pigeonpea Intercrop in Hamelmalo Region of Eritrea

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Journal of Geoscience and Environment Protection 2016年第4期4卷 63-73页

作者： Tesfalem Weldeslassie ramesh Prasad tripathi Woldeselassie Ogbazghi Department of Land Resources and Environment Hamelmalo Agricultural College Keren Eritrea

Sorghum (Sorghum bicolor L. Moench) is cultivated as monocrop in Eritrea. Efforts were made to grow sorghum-pigeonpea (Cajanus cajan L. Millspp.) intercrop on the tillage, fertilizers and supplementary irrigations necessary for sorghum. Experiments were conducted in terraced fields at Hamelmalo during 2013-15 to evaluate growth and yield of sorghum-pigeonpea intercrop in split plot design with conventional tillage (CT), reduced tillage (RT) and zero tillage (ZT) in main plots and rainfed (I0), 50% of full irrigation (I1), 75% of full irrigation (I2) and 100% of full irrigation (I3) in subplots. All irrigations were stopped 15 days before sorghum maturity. Full irrigation was 60 mm applied at 50% depletion of available soil water in 1 m profile. Sorghum growth was faster than pigeonpea until 85 days from planting and pigeonpea growth accelerated only after sorghum harvesting. About 80% of sorghum roots were within 0.6 m profile but more than 75% of pigeonpea roots were below 0.60 m depth. This showed a weaker competition between the two crops for nutrients, water and light. Both grain and stover yields of sorghum were optimum in RT + I2 during the 2 years. Highest grain yield was 6900 kg·ha-1 in RT + I3 in 2013, which was at par with that in RT + I2. Mean residual soil moisture at sorghum harvesting was 74 mm·m-1, which decreased to 8 mm·m-1 by pigeonpea harvesting. Residual moisture was more in the irrigated than non-irrigated plots. Pigeonpea yields were optimum (1363 kg·ha-1) in RT + I3 and lowest (297 kg·ha-1) in ZT + I0. Average water use by sorghum-pigeonpea was 374 mm by sorghum harvesting and 438 mm by pigeonpea harvesting, producing total sorghum equivalent yield of 7475 kg·ha-1. This raised average water use efficiency from 12.6 kg·ha-1·mm-1 at sorghum harvesting to 17.1 kg

关键词： Residual Soil Moisture Sorghum-Pigeonpea Intercrop Supplementary Irrigation Water Use Efficiency

Irrigation and Nitrogen Requirements of Wheat under Shallow Water Table Conditions of Asmara, Eritrea

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Journal of Geoscience and Environment Protection 2016年第4期4卷 80-87页

作者： Fekadu Tesfamichael ramesh Prasad tripathi Mehreteab Tesfai Department of land Resources and Environment Hamelmalo Agricultural College Keren Eritrea

Wheat (Triticum astivum L.) is traditionally rainfed in Eritrea. Yields are low because of poor soil management and low water and nutrient inputs. A field experiment was conducted in Akria farm, located in the outskirts of Asmara. The soil was clay loam associated with non-saline shallow water tables fluctuating from 0.4 to 1.2 m depths during the crop season. Wheat variety Wedel Nile was planted in split plot design with four levels of supplementary irrigations (SI) viz. I1 (rainfed, 0 SI), I2 (1/3 of full SI), I3 (2/3 of full SI), and I4 (full SI) in main plots and three levels of nitrogen viz. N1 (18 kg N haǃ), N2 (50 kg N haǃ), and N3 (100 kg N haǃ) as sub-plots in three replications. Full SI refers to amount of water necessary to replenish soil moisture deficit in the root zone from field capacity to 50% depletion of the available soil moisture. Groundwater table was constant around 0.4 m depth for 32 days from planting and declined slowly thereafter. Wetness around 0.3 m depth was thus near field capacity until second week of December and reduced thereafter with declining water table. Average soil moisture depletion was 94 mm under rainfed and 64 mm under full irrigation. No symptoms of wilting were observed in any of the treatments due to shallow water tables. Upward flux from the water table was 4.6 mm·d-1 until 30 days from planting, which declined to 0.2 mm·d-1 when the water table declined below 0.9 m depth. Optimum yield of wheat (5603 kg·ha-1) was obtained by application of 58 mm irrigation (I3) and 100 kg·ha-1 nitrogen (N3). Total water use for optimum yield of wheat was 382 mm and water use efficiency was 14.7 kg·ha-1·mm-1. Contribution from water table to the evapotranspiration requirements of wheat was highest (61%) under rainfed (I1

关键词： Evapotranspiration Nitrogen Supplementary Irrigation Water Table Contribution Water Table Wheat

Heat-tolerant maize for rainfed hot,dry environments in the lowland tropics:From breeding to improved seed delivery

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The Crop Journal 2023年第4期11卷 986-1000页

作者： Pervez H.Zaidi Madhumal Thayil Vinayan Sudha K.Nair Prakash H.Kuchanur ramesh kumar Shyam Bir Singh Mahendra Prasad tripathi Ayyanagouda Patil Salahuddin Ahmed Aamir Hussain Atul Prabhakar Kulkarni Passang Wangmo Mitchell R.Tuinstra Boddupalli M.Prasanna International Maize and Wheat Improvement Center(CIMMYT) Hyderabad 502324India University of Agricultural Sciences Raichur 584104KarnatakaIndia ICAR-Indian Institute of Maize Research Ludhiana 141001BiharIndia National Maize Research Program RampurChitwan 44200Nepal Bangladesh Wheat and Maize Research Institute Dinajpur-5201Bangladesh Maize and Millet Research Institute YusafwalaSahiwal 57000Pakistan Agriculture Research and Development Centre Wengkhar 43001Bhutan Institute of Plant Sciences Purdue UniversityWest LafayetteIN 47906USA International Maize and Wheat Improvement Center(CIMMYT) NairobiKenya

Climate change-induced heat stress combines two challenges:high day-and nighttime temperatures,and physiological water deficit due to demand-side drought caused by increase in vapor-pressure *** is one of the major factors in low productivity of maize in rainfed stress-prone environments in South Asia,affecting a large population of smallholder farmers who depend on maize for their sustenance and *** International Maize and Wheat Improvement Center(CIMMYT)maize program in Asia,in partnership with public-sector maize research institutes and private-sector seed companies in South Asian countries,is implementing an intensive initiative for developing and deploying heat-tolerant maize that combines high yield potential with resilience to heat and drought *** the integration of novel breeding tools and methods,including genomics-assisted breeding,doubled haploidy,fieldbased precision phenotyping,and trait-based selection,new maize germplasm with increased tolerance to heat stress is being developed for the South Asian *** a decade of concerted effort has resulted in the successful development and release of 20 high-yielding heat-tolerant maize hybrids in CIMMYT genetic *** public–private partnerships,eight hybrids are presently being deployed on over 50,000 ha in South Asian countries,including Bangladesh,Bhutan,India,Nepal,and Pakistan.

关键词： Climate change Drought Heat stress Lowland tropics Maize Vapor pressure deficit

Rice Production Prospects in Eritrea

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Journal of Water Resource and Protection 2015年第17期7卷 1429-1434页

作者： ramesh Prasad tripathi Woldeselassie Ogbazghi Semere Amlesom Department of Land Resources and Environment Hamelmalo Agricultural College Keren Eritrea

Rice is not cultivated in Eritrea because of its high water requirements and arid to semiarid conditions. However, most agricultural watersheds in Eritrea are associated with >80% non-agricultural lands, which produce significant runoff that can be diverted for use by rice crop. Experiments were conducted at Hamelmalo Agricultural College, Eritrea, using four NERICA rice varieties viz. N1, N4, N10 and N11 under rainfed (Io) and limited supplementary irrigations (I) in 3 replications. Results showed that plants were taller under limited irrigations than rainfed. Among the 4 varieties, N11 was most affected by water stress in which plant height was 0.72 m under rainfed and 0.89 m under limited irrigations. Effective tillers were highest (6) in N11 under limited irrigations and lowest (2) in N10 under rainfed. Panicles were shorter (0.20 m) in N10 and longer (0.23 - 0.24 m) in N1 and N11. Irrigations delayed maturity by 6 - 15 days. Water use by N11 was higher both under limited irrigations (987 mm) and rainfed (477 mm) and lower by N10 under rainfed (457 mm). Root growth in all the varieties was better under irrigations (I) than rainfed (Io). Roots were limited to 0.7 m depth under rainfed (Io) but grew down to 0.8 m in N1, N4 and N11 under limited irrigations (I). Roots in N10 were limited to 0.5 m depth under Io and 0.7 m under I. More than 63% roots in N10 were in 0 - 0.1 m layer under rainfed as against less than 55% under limited irrigations. In lower layers, roots under Io were more in N4 than others, which is a beneficial trait for better performance under semiarid environments. Roots in N11 were better and uniformly distributed in lower layers under irrigated conditions. Rooting patterns and grain yields showed that N11 was most responsive to irrigations but susceptible to water stress and N4 was best under rainfed followed by N10. N4 was next to N11 under irrigated conditions.

关键词： Irrigated and Rainfed Rice NERICA Rice Eritrea Root Growth Water Use Yield

Tillage and Irrigation Requirements of Sorghum (<i>Sorghum bicolor</i>L.) at Hamelmalo, Anseba Region of Eritrea

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Open Journal of Soil Science 2015年第12期5卷 287-298页

作者： ramesh P. tripathi Isaac Kafil Woldeselassie Ogbazghi Department of Land Resources and Environment Hamelmalo Agricultural College Keren Eritrea

Most Eritrean farmers do not adopt soil conservation measures and till even sloppy fields 2 - 4 times for planting sorghum (Sorghum bicolor L.) with a view to facilitate rainwater intake. Field experiments were conducted at Hamelmalo to optimize tillage and irrigation requirements of sorghum in loamy sand. Tillage treatments were conventional tillage (4 times) on existing slopes (CTf), conventional tillage on managed plots (terraced) with residue (CTm + R) and without residue (CTm - R), reduced tillage (single tillage 4 days after heavy rainfall) on managed plots with residue (RTm + R) and without residue (RTm - R) and no tillage (direct planting) on managed plots with residue (NTm + R) and without residue (NTm - R) randomized in four replications. Tillage in CTm and CTf was same. Experiment was repeated in year II along with a new experiment in split plot design with same tillage treatments in main plots and 4 irrigation treatments in subplots in 3 replications. Irrigation treatments were rainfed (I0), 70 mm irrigation at 50% depletion of soil moisture in CTm - R from 1 m profile after end of monsoon (I1), 70 mm irrigation 7 days after irrigation in I1 (I2), and 70 mm irrigation 7 days after irrigation in I2 (I3). Bulk density increased and infiltration rates decreased by harvesting due to tillage but changes were lower in residue plots of NT and RT than CT. Optimum soil moisture for emergence of sorghum was within 0.145 ± 0.002 m3 m-3 at which soil strength was well below critical level for root growth. Soil strength in tilled layer due to intermittent wetting and drying following planting exceeded 2000 k Pa when dried below 0.143 m3 m-3 moisture. Soil profile in CTf did not recharge by rainfall even by end of the rainy season, whereas it was fully wetted in level and terraced plots. Conservation measures resulted 80 - 150 mm of residual moisture per 2 m of soil profile at sorghum harvesting. Residual moisture was relatively more in residue and irrigat

关键词： Rainwater Conservation Residue Mulch Semiarid Soil Properties Sorghum Yield Tillage

Effect of Puddling and Compaction on Water Requirements of Rice at Hamelmalo, Eritrea

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Computational Water, Energy, and Environmental Engineering 2016年第2期5卷 27-37页

作者： Bahlbi Goitom ramesh Prasad tripathi Woldeselassie Ogbazghi Tesfalem Weldeslassie Department of Land Resources and Environment Hamelmalo Agricultural Colleg Keren Eritrea

Eritrean farmers can cultivate rice by harvesting runoff from >82% available non-agricultural land in agricultural watersheds for crop use and reducing percolation through optimization of tillage. Experiments were conducted with NERICA rice, N11, to optimize irrigation requirements and puddling and compaction to reduce percolation. Experimental field was adjacent to Anseba River at downstream end of the watershed and a pond on the upstream to intercept runoff. Irrigation treatments were runoff farming with maximum runoff application depth of 10 mm (I1), and 50 mm irrigation two (I2), five (I3), and seven (I4) days after disappearance of ponded water in main plots and puddling by one (T1), two (T2) and three (T3) passes of puddler and compaction by three (T4), four (T5) and five (T6) passes of 600 kg roller in sub plots in 3 replications. Soil profile was loam in the surface 0.45 m and coarse sandy loam below forming porous belt. Soil submergence was difficult to maintain, but water table was developed in soil profile due to inflow of seepage from the river and pond. Depth to the water table was within 1.5 ± 0.1 m for >2 months and receded down to 1.7 m by crop maturity. Soil wetness was near field capacity around 0.7 m depth and increased below due to natural sub-irrigation from the water table. Rice roots penetrated 0.8 m in the puddled plots and 0.7 m in the compacted plots. Residual soil moisture of 135 - 146 mm·m-1 after rice harvesting provides opportunity for planting rapeseed mustered following rice. Puddling was superior to compaction in loam soil. Puddling twice and irrigation 50 mm 7 days after ponded water vanished from surface was sufficient for optimum rice grain yield of 4346 kg·ha-1 and straw yield of 4458 kg·ha-1. Optimum puddling and irrigation schedules reduced crop duration by 6 days without significantly a

关键词： Compaction Irrigation NERICA Rice Puddling Runoff Farming Water Table