Unsteady boundary layer flow and heat transfer over an exponentially shrinking sheet with suction in a copper-water nanofluid

An analysis of unsteady boundary layer flow and heat transfer over an exponentially shrinking porous sheet filled with a copper-water nanofluid is presented. Water is treated as a base fluid. In the investigation, non-uniform mass suction through the porous sheet is considered. Using Keller-box method the transformed equations are solved numerically. The results of skin friction coefficient, the local Nusselt number as well as the velocity and temperature profiles are presented for different flow parameters. The results showed that the dual non-similar solutions exist only when certain amount of mass suction is applied through the porous sheet for various unsteady parameters and nanoparticle volume fractions. The ranges of suction where dual non-similar solution exists, become larger when values of unsteady parameter as well as nanoparticle volume fraction increase. So, due to unsteadiness of flow dynamics and the presence of nanoparticles in flow field, the requirement of mass suction for existence of solution of boundary layer flow past an exponentially shrinking sheet is less. Furthermore, the velocity boundary layer thickness decreases and thermal boundary layer thickness increases with increasing of nanoparticle volume fraction in both non-similar solutions. Whereas, for stronger mass suction, the velocity boundary layer thickness becomes thinner for the first solution and the effect is opposite in the case of second solution. The temperature inside the boundary layer increases with nanoparticle volume fraction and decreases with mass suction. So, for the unsteadiness and for the presence of nanoparticles, the flow separation is delayed to some extent

Supplier selection by F-compromise method: a case study of cement industry of NE India

In this paper, we initially conducted a brief review of supplier selection methods to find most cited multi-criteria decision making method, present trend of supplier selection and most cited criteria for supplier selection. Our study reveals that irrespective of several limitations of analytic hierarchy process (AHP), AHP and its integrated model is most preferred supplier selection method. Present research trend of supplier selection gives more emphasises on multiple sourcing instead of single sourcing. Based on our initial study, a suitable integrated model is proposed. In this integrated model, fuzzy analytic hierarchy process (FAHP) and VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje; in Serbian) is used to select suppliers from a predefined supplier base. Multi-objective genetic algorithm (MOGA) is used further to allocate order among suppliers. Finally, a case study is discussed to use proposed method

Variance

Variance continues my long-standing interest in the Victorian polymath Francis Galton, having first researched Galton as part of my (2000) publication Death’s Witness and associated MPhil. This research formed the basis of my (2005) artist’s film Vanitas: Seed-Head, based on Galton’s composite photographic portraits and his proto-genetic inheritance studies. Variance is also influenced by Galton’s studies of inheritance (all six photographs are of my extended family) but extends this research into an exploration of his pioneering work on statistics and biometrics. According to Elizabeth Edwards (1997) Francis Galton’s composite photographs constituted “…lived concepts – embodied or concrete ideas to render the unseen or non-existent empirically: in other words, a taxonomic essence within a dialectic of the visible and invisible.” Variance plays on this tension between the seen and unseen, the known and unknown, to comment on the impossibility of ever being able to construct human typologies in the way Galton attempted. Variance incorporates scanning electron microscopy images of brain activity to create a series of ‘thought portraits’, which bring into question contemporary neuro-biological imaging technologies and interpretations, which allegedly allow neuroscientists to ‘see’ and ‘measure’ our thoughts and emotions. Variance raises awareness of the hidden nuances of scientific interpretation and meaning that lurk just below the surface of the posited reality of neuroscience

Supplier selection by F-compromise method: a case study of cement industry of NE India

In this paper, we initially conducted a brief review of supplier selection methods to find most cited multi-criteria decision making method, present trend of supplier selection and most cited criteria for supplier selection. Our study reveals that irrespective of several limitations of analytic hierarchy process (AHP), AHP and its integrated model is most preferred supplier selection method. Present research trend of supplier selection gives more emphasises on multiple sourcing instead of single sourcing. Based on our initial study, a suitable integrated model is proposed. In this integrated model, fuzzy analytic hierarchy process (FAHP) and VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje; in Serbian) is used to select suppliers from a predefined supplier base. Multi-objective genetic algorithm (MOGA) is used further to allocate order among suppliers. Finally, a case study is discussed to use proposed method

Effect of integrated nutrient management on the nutrient accumulation and status of post-harvest soil of brinjal (Solanum melongena L.) under Nadia conditions (West Bengal), India

A field experiment was carried out at the Central Research Farm, Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India to study the effects of integrated nutrient management on the nutrient accumulation (dry weight recoveries) in brinjal and plant nutrient status of the post- harvest soil of brinjal under Nadia conditions. The results revealed that the treatment consisting of 75% RDF (RDF i.e. N:P:K:: 125:100:50) + Azospirillum + phosphate solubilising bacteria (PSB) + Borax @ 10 kg ha-1 recorded the highest oxidizable organic carbon (8.049 g kg-1), total nitrogen (1.05 g kg-1) , available nitrogen (212.67g kg-1), available phosphorus (76.20g kg-1) and available potassium (177.59 g kg-1) in the post harvest soils of brinjal. On the other hand, 75% RDF + Azospirillum + PSB + FeSO4 @ 50 kg ha-1 recorded the highest available iron (26.14 kg ha-1) and the treatment consisting of 75% RDF + Azospirillum + PSB + ZnSOâ‚„ @ 25 kg ha-1 recorded the highest soil available zinc (7.62 kg ha-1) while 75% RDF + Azo + PSB + Borax @ 10 kg ha-1 recorded the highest available Boron content (0.78 kg ha-1) of the post harvest soil of Brinjal. Highest brinjal yield (14.96 t ha-1) was supported by the treatment consisting of 75% RDF + Azospirillum + PSB + Boron @ 10 Kg ha-1. Meager information was available regarding the performance of integrated application of organics and micronutrient on brinjal in the experimental location. The present study may enlighten this unexplored section of nutrient management in brinjal

Chemically Reactive Solute Distribution in a Steady MHD Boundary Layer Flow over a Stretching Surface

The paper is concerned to find the distribution of the chemically reactant solute in the MHD flow of an electrically conducting viscous incompressible fluid over a stretching surface. The first order chemical reaction and the variable solute distribution along the surface are taken into consideration. The governing partial differential equations along with appropriate boundary conditions for flow field and reactive solute are transformed into a set of non-linear self-similar ordinary differential equations by using scaling group of transformations. An exact analytic solution is obtained for the velocity field. Using this velocity field, we obtain numerical solution for the reactant concentration field. It reveals from the study that the values of concentration profile enhances with the increase of the magnetic field and decreases with increase of Schmidt number as well as the reaction rate parameter. Most importantly, when the solute distribution along the surface increases then the concentration profile decreases

Non-equilibrium Dynamics of O(N) Nonlinear Sigma models: a Large-N approach

We study the time evolution of the mass gap of the O(N) non-linear sigma model in 2+1 dimensions due to a time-dependent coupling in the large-$N$ limit. Using the Schwinger-Keldysh approach, we derive a set of equations at large $N$ which determine the time dependent gap in terms of the coupling. These equations lead to a criterion for the breakdown of adiabaticity for slow variation of the coupling leading to a Kibble-Zurek scaling law. We describe a self-consistent numerical procedure to solve these large-$N$ equations and provide explicit numerical solutions for a coupling which starts deep in the gapped phase at early times and approaches the zero temperature equilibrium critical point $g_c$ in a linear fashion. We demonstrate that for such a protocol there is a value of the coupling $g= g_c^{\rm dyn}> g_c$ where the gap function vanishes, possibly indicating a dynamical instability. We study the dependence of $g_c^{\rm dyn}$ on both the rate of change of the coupling and the initial temperature. We also verify, by studying the evolution of the mass gap subsequent to a sudden change in $g$, that the model does not display thermalization within a finite time interval $t_0$ and discuss the implications of this observation for its conjectured gravitational dual as a higher spin theory in $AdS_4$.Comment: 22 pages, 9 figures. Typos corrected, references rearranged and added.v3 : sections rearranged, abstract modified, comment about Kibble-Zurek scaling correcte

Soil conservation issues in India

Despite years of study and substantial investment in remediation and prevention, soil erosion continues to be a major environmental problem with regard to land use in India and elsewhere around the world. Furthermore, changing climate and/or weather patterns are exacerbating the problem. Our objective was to review past and current soil conservation programmes in India to better understand how production-, environmental-, social-, economic- and policy-related issues have affected soil and water conservation and the incentives needed to address the most critical problems. We found that to achieve success in soil and water conservation policies, institutions and operations must be co-ordinated using a holistic approach. Watershed programmes have been shown to be one of the most effective strategies for bringing socio-economic change to different parts of India. Within both dryland and rainfed areas, watershed management has quietly revolutionized agriculture by aligning various sectors through technological soil and water conservation interventions and land-use diversification. Significant results associated with various watershed-scale soil and water conservation programmes and interventions that were effective for reducing land degradation and improving productivity in different parts of the country are discussed

Steady boundary layer flow and reactive mass transfer past an exponentially stretching surface in an exponentially moving free stream

An analysis is made to study the steady two-dimensional boundary layer flow and reactive mass transfer past an exponentially stretching sheet in an exponentially moving free stream. The reaction rate of solute and the wall concentration distribution are taken variable. The governing equations are transformed and then solved numerically. The study reveals that the momentum boundary layer thickness is considerably smaller than that of stagnation point flow over stretching sheet. Due to increase of Schmidt number and reaction rate parameter the mass transfer considerably enhances. Importantly, for solute distribution, in addition to mass transfer, mass absorption occurs in certain situations

MHD Stagnation-Point Flow of Casson Fluid and Heat Transfer over a Stretching Sheet with Thermal Radiation

The two-dimensional magnetohydrodynamic (MHD) stagnation-point flow of electrically conducting non-Newtonian Casson fluid and heat transfer towards a stretching sheet have been considered. The effect of thermal radiation is also investigated. Implementing similarity transformations, the governing momentum, and energy equations are transformed to self-similar nonlinear ODEs and numerical computations are performed to solve those. The investigation reveals many important aspects of flow and heat transfer. If velocity ratio parameter (B) and magnetic parameter (M) increase, then the velocity boundary layer thickness becomes thinner. On the other hand, for Casson fluid it is found that the velocity boundary layer thickness is larger compared to that of Newtonian fluid. The magnitude of wall skin-friction coefficient reduces with Casson parameter (β). The velocity ratio parameter, Casson parameter, and magnetic parameter also have major effects on temperature distribution. The heat transfer rate is enhanced with increasing values of velocity ratio parameter. The rate of heat transfer is enhanced with increasing magnetic parameter M for B > 1 and it decreases with M for B < 1. Moreover, the presence of thermal radiation reduces temperature and thermal boundary layer thickness