Small-scale Factors Research Articles

Small Scale Industries and Factors Affecting their Performance in Indian Context: A Literature Review

Small Scale Industries and Factors Affecting their Performance in Indian Context: A Literature Review

Numerical modeling study of a man-made low-permeability barrier for the compressed air energy storage in high-permeability aquifers

Compressed air energy storage (CAES) is a grid-scale energy storage technology for intermittent energy, as proven by the decades-long successful operation of two existing compressed air energy storage in cavern (CAESC) power plants. Because of the limited availability of salt domes appropriate for CAESC, the more widely available aquifers (compressed air energy storage in aquifers, CAESA) have recently attracted considerable attention as candidates for CAES. An ideal aquifer for CAESA is highly permeable around the well to facilitate easy injection and withdrawal of air, but the high-permeability region is surrounded by low-permeability zones to minimize the loss of injected air and decrease in energy efficiency. However, such ideal geological structures are not always available in nature. Therefore, the potential of creating man-made low-permeability barrier in high-permeability aquifers is very interesting. In this paper, we investigate the feasibility of man-made low-permeability barriers in high-permeability aquifers using the numerical simulator TOUGH2/Gel to calculate the three-component flow (including a miscible gelling liquid). The simulation results show that an expected low-permeability barrier can be created by injecting grout with certain properties, and the altered aquifer performs well for CAESA. Additional sensitivity studies are also performed to reveal the effects of the various factors on the success of the low-permeability barrier creation, including the critical solidification concentration, the scale factor of the time dependence of the grout viscosity, the relative density of the grout, and the volume of the follow-up water injection. The results indicate that, in a horizontal aquifer, low critical solidification concentrations, and small scale factors are generally preferred and the density of grout should be close to that of the in situ water. For the given volume of the injected grout, there is an optimal follow-up water injection that will create the largest storage space without damaging the barrier. These results may help to extend the candidate sites for CAESA and the prospect of large scale energy storage.

Sensitivity of extreme precipitation to temperature: the variability of scaling factors from a regional to local perspective

Potential increases in extreme rainfall induced hazards in a warming climate have motivated studies to link precipitation intensities to temperature. Increases exceeding the Clausius–Clapeyron (CC) rate of 6–7%/°C–1 are seen in short-duration, convective, high-percentile rainfall at mid latitudes, but the rates of change cease or revert at regionally variable threshold temperatures due to moisture limitations. It is unclear, however, what these findings mean in term of the actual risk of extreme precipitation on a regional to local scale. When conditioning precipitation intensities on local temperatures, key influences on the scaling relationship such as from the annual cycle and regional weather patterns need better understanding. Here we analyze these influences, using sub-hourly to daily precipitation data from a dense network of 189 stations in south-eastern Austria. We find that the temperature sensitivities in the mountainous western region are lower than in the eastern lowlands. This is due to the different weather patterns that cause extreme precipitation in these regions. Sub-hourly and hourly intensities intensify at super-CC and CC-rates, respectively, up to temperatures of about 17 °C. However, we also find that, because of the regional and seasonal variability of the precipitation intensities, a smaller scaling factor can imply a larger absolute change in intensity. Our insights underline that temperature precipitation scaling requires careful interpretation of the intent and setting of the study. When this is considered, conditional scaling factors can help to better understand which influences control the intensification of rainfall with temperature on a regional scale.

Exact closed form solution for the analysis of the transverse vibration mode of a Nano-Timoshenko beam with multiple concentrated masses

Concentrated masses mounted on a Nanobeam have important effects on its transverse vibrations. In this paper the effects of concentrated masses on lateral vibration of a Nanobeam is investigated by utilizing two different points of view about shear force in the beam. The investigation is conducted with and without considering small scale effect on shear force. Timoshenko beam and nonlocal theories have been used in Newton's second law to model transverse dynamic behavior of a Nanobeam; then the mathematical model of concentrated masses is imposed into the equations of motion by using Dirac's delta function. After obtaining exact closed form solution, basic functions are used to simplify calculations. Different parameters of the Nanobeam are used to study transverse vibration of Nanobeam carrying concentrated masses. These parameters include number, mass and location of concentrated masses and length, cross section area and small scale factor of Nanobeam. Finally, the effects of these parameters are presented in diagrams for two points of view. The diagrams show significant difference between consideration and disregarding of small scale factor in shear force in higher natural frequencies of Nanobeam.

Experimental and analytical investigations of vibrational behavior of U-shaped atomic force microscope probe considering thermal loading and the modified couple stress theory

In this study, experimental and analytical models of a U-shaped atomic force microscopic (AFM) probe are studied based on the modified couple stress theory (MCST). The experimental setup is a commercially fabricated U-shaped probe AN2-300 mounted in the atomic force microscope afm+ system. In the analytical model, the U-shaped probe of the AFM is simulated as a three-beam model (TBM). The governing equations of motion and boundary conditions are obtained by combination of basic equations of the modified couple stress theory and Hamilton’s principle. It is found that the natural frequencies of the AFM predicted by the MCST are size-dependent. The difference between the natural frequencies predicted by the MCST and the classical beam model is very significant when the ratio of characteristic size to internal material length scale parameter is approximately equal to one, but it is diminishing with increase in the ratio. In order to validate the results, the mathematical and experimental models have been compared with each other. It is seen that the analytical model based on MCST has excellent agreement with experimental results. Also, the natural frequencies of the probe have been obtained for different temperature values, aspect ratios, and small scale factor amounts. The results show, natural frequency decrease with increase in temperature value.

Dynamic tests in a steel catenary riser reduced scale model

ABSTRACTExperimental investigations were conducted on a steel catenary riser (SCR) with different stiffness seafloor models both in dry and wet conditions. The motion oscillator and cell load connect the riser model in a tank, and forced motions with different amplitudes and frequencies were studied. Model tests are conducted in air and a small scale factor (1/435) is used. This model has been built having as reference a riser prototype in 900 m water depth and the numerical analysis is carried out in time domain using the developed CABLE3D. Results demonstrate the influence of the platform in-plane motion on the dynamic response of the riser model, and both of them are consistently good. This study provides a novel and simple experimental tool developed for testing of the SCR global dynamic analysis, and discusses the results including motion response, top tension and dynamic curvature near touchdown zone.

Graviton creation by small scale factor oscillations in an expanding universe

We treat quantum creation of gravitons by small scale factor oscillations around the average of an expanding universe. Such oscillations can arise in standard general relativity due to oscillations of a homogeneous, minimally coupled scalar field. They can also arise in modified gravity theories with a term proportional to the square of the Ricci scalar in the gravitational action. The graviton wave equation is different in the two cases, leading to somewhat different creation rates. Both cases are treated using a perturbative method due to Birrell and Davies, involving an expansion in a conformal coupling parameter to calculate the number density and energy density of the created gravitons. Cosmological constraints on the present graviton energy density and the dimensionless amplitude of the oscillations are discussed. We also discuss decoherence of quantum systems produced by the spacetime geometry fluctuations due to such a graviton bath.

Monetary, fiscal and oil shocks: Evidence based on mixed frequency structural FAVARs

Large scale factor models have been often adopted both for forecasting and to identify structural shocks and their transmission mechanism. Mixed frequency factor models have been also used in a reduced form context, but not for structural applications, and in this paper we close this gap. First, we adapt a simple technique developed in a small scale mixed frequency VAR and factor context to the large scale case, and compare the resulting model with existing alternatives. Second, using Monte Carlo experiments, we show that the finite sample properties of the mixed frequency factor model estimation procedure are quite good. Finally, to illustrate the method we present three empirical examples dealing with the effects of, respectively, monetary, oil, and fiscal shocks.

Image Resolution Enhancement Using Wavelet Domain Transformation and Sparse Signal Representation

Image resolution enhancement or super-resolution (SR) problem generates a high resolution (HR) image from one or a set of low resolution (LR) images. In the past two decades, a wide variety of resolution enhancement algorithms have been proposed. These methods are confined to small scaling factors. This paper presents a novel single image resolution enhancement algorithm in wavelet domain which operates at high scaling factors. First, we perform subband decomposition on the input LR image by using discrete wavelet transform (DWT). It decomposes the LR image into different frequency subbands namely low-low (LL), low-high (LH), high-low (HL) and high-high (HH). In parallel we apply sparse representation based interpolation method on the LR image. Next, we process the three high frequency subbands in wavelet domain by applying bicubic interpolation. Finally, the interpolated high frequency subbands in addition to the sparse recovered solution are combined to produce a HR image using inverse discrete wavelet transform (IDWT). Experiments on different LR test images demonstrate that our approach produces relatively less artifacts compared to the existing methods.

The contribution of patch‐scale conditions is greater than that of macroclimate in explaining local plant diversity in fragmented forests across Europe

AbstractAimMacroclimate is a major determinant of large‐scale diversity patterns. However, the influence of smaller‐scale factors on local diversity across large spatial extents is not well documented. Here, we quantify the relative importance of local (patch‐scale), landscape‐scale and macroclimatic drivers of herbaceous species diversity in small forest patches in agricultural landscapes across Europe.LocationDeciduous forest patches in eight regions along a macroclimatic gradient from southern France to central Sweden and Estonia.MethodsThe diversity of forest specialists and generalists at three levels (whole forest patch, sampling plots within patches and between scales) was related to patch‐scale (forest area, age, abiotic and biotic heterogeneity), landscape‐scale (amount of forest, grasslands and hedgerows around the patch, patch isolation) and macroclimatic variables (temperature and precipitation) using generalized linear mixed models and variation partitioning for each group of variables.ResultsThe total amount of explained variation in diversity ranged from 8% for plot‐scale diversity of generalists to 54% for patch‐scale diversity of forest specialists. Patch‐scale variables always explained more than 60% of the explained variation in diversity, mainly due to the positive effect of within‐patch heterogeneity on patch‐scale and between‐scale diversities and to the positive effect of patch age on plot‐scale diversity of forest specialists. Landscape‐scale variables mainly contributed to the amount of explained variation in plot‐scale diversity, being more important for forest specialists (21%) than for generalists (18%). Macroclimatic variables contributed a maximum of 11% to the plot‐scale diversity of generalists.Main conclusionsMacroclimate poorly predicts local diversity across Europe, and herbaceous diversity is mainly explained by habitat features, less so by landscape structure. We show the importance of conserving old forest patches as refugia for typical forest species, and of enhancing the landscape context around the patches by reducing the degree of disturbance caused by agriculture.

Estimation of surface-wave group velocity using slant stack in the generalized S-transform domain

We have developed the slant stacking approach in the generalized S-transform (GST) domain of seismic data for the estimation of the group velocity of the multimodal surface wave. We used two versions of the GST. The constant-scale GST uses a constant scaling factor in the Gaussian window to control the spectral time-frequency localization. We found that a smaller scaling factor should be chosen for the low-frequency surface wave, whereas for higher frequencies, a larger scaling factor should be chosen. Therefore, the transform exhibits a trade-off in the group velocity resolution of low frequencies with small values of the scaling factor and the group velocity resolution of high frequencies with large values of the scaling factor. The modified S-transform (MST), another version of the GST used in this study, enhanced the time-frequency resolution by projecting the frequency into a linear frequency function in the Gaussian window. This property allowed us to estimate the group velocity for a broad range of frequencies. We demonstrated the robustness of the MST for the estimation of the group velocity by synthetic and real data examples.

Spatial Characteristics: A Planners View of Locational Pattern and Underlying Factors among Small Scale Industries in Ondo State of Nigeria

This study investigated the locational pattern and the factors among small scale industries (SSI) in Ondo state of Nigeria. Three hundred and fifty three (353) enterprises were sampled across the nine selected settlements spread across the three senatorial regions of the state. The study made use of quadrant count analysis to investigate the distributional pattern, t-test to compare the distributional pattern among formal and informal small scale industries and factor analysis to isolate major locational factors. The study established that there existed significant difference in the distributional patterns of small scale enterprises in the sampled settlements. For example, while 40% of the sampled industries were located in Ondo Central, 31% were in Ondo South, while 28% were in Ondo North. Moreover, 82% of the industries were concentrated in the major urban areas of Akure, Ikare and Okitipupa, with the minor urban areas of Ode Aye, Ugbe and Obaile accounted for 11.3%, while the villages of Iboropa, Aponmu and Ikoya were almost insignificant with 5.9%. The study further established that the distributional pattern of SSI in Ondo North was regular (Iboropa V.M.R 0.15, Ikare, V.M.R 0.41, and Ugbe V.M.R 0.32), in Ondo Central, the SSI did not show regular pattern, here while some were regular (Obaile V.M.R 0.32) Some exhibited random pattern (Aponmu V.M.R 0.91) and Akure clearly showed clustered pattern (V.M.R 1.30). In Ondo South, the tendency was regular distribution, Ikoya and Ode Aye being Regular (V.M.R 0.27, V.M.R 0.81) while Okitipupa was clustered (V.M.R 1.70). An application of Anova revealed that there is no significant uniformity in V.M.R values of all the 9 settlements, since the calculated F ratio (1.0494) was less than the tabulated F ratio (5.14).Yet an application of factor analysis revealed that access to labour, power and proprietors personal preferences (0.77, 0.72,and,0.57 loadings) were major factors of location.Key Words: Small scale industries, Distributional pattern, Locational factors, Agglomeration, Proprietors

Small-scale Timoshenko beam element

Abstract Higher-order gradient continuum mechanics theories are of critical importance as they can afford to describe the size-dependent mechanical behavior of micro-scale structures. In this article, based on the most general form of strain gradient elasticity theory, a new extended Timoshenko beam element capable of accommodating size effects is introduced. To this end, the higher-order tensors of energy pairs in the energy functional are vectorized and represented in the quadratic form first. This gives way to realize the stiffness and mass matrices of the newly proposed element. Compared to the standard Timoshenko beam element, the new element requires two additional nodal degrees of freedom (d.o.f.) consisting of derivatives of lateral translation and rotation, which means a total of 4 d.o.f. per node. Therefore, the Hermite functions are employed to construct the shape functions of this new element. The proposed element is indicated to exhibit stiffer character, making it desirable when dealing with the problems at the microscale. Also, the standard Timoshenko beam element is recovered when the small scale factor tends to zero. Using this new element, the free vibration and bending of Timoshenko microbeams are investigated. The results are compared with those available in the literature and excellent agreement is achieved.

A hybrid continuum and molecular mechanics model for the axial buckling of chiral single-walled carbon nanotubes

The purpose of this study is to describe the axial buckling behavior of chiral single-walled carbon nanotubes (SWCNTs) using a combined continuum-atomistic approach. To this end, the nonlocal Flugge shell theory is implemented into which the nonlocal elasticity of Eringen incorporated. Molecular mechanics is used in conjunction with density functional theory (DFT) to precisely extract the effective in-plane and bending stiffnesses and Poisson's ratio used in the developed nonlocal Flugge shell model. The Rayleigh-Ritz procedure is employed to analytically solve the problem in the context of calculus of variation. The results generated from the present hybrid model are compared with those from molecular dynamics simulations as a benchmark of good accuracy and excellent agreement is achieved. The influences of small scale factor, commonly used boundary conditions and chirality on the critical buckling load are fully explored. It is indicated that the importance of the small length scale is affected by the type of boundary conditions considered.

Biogeography and Change among Regional Coral Communities across the Western Indian Ocean

Coral reefs are biodiverse ecosystems structured by abiotic and biotic factors operating across many spatial scales. Regional-scale interactions between climate change, biogeography and fisheries management remain poorly understood. Here, we evaluated large-scale patterns of coral communities in the western Indian Ocean after a major coral bleaching event in 1998. We surveyed 291 coral reef sites in 11 countries and over 30° of latitude between 2004 and 2011 to evaluate variations in coral communities post 1998 across gradients in latitude, mainland-island geography and fisheries management. We used linear mixed-effect hierarchical models to assess total coral cover, the abundance of four major coral families (acroporids, faviids, pocilloporids and poritiids), coral genus richness and diversity, and the bleaching susceptibility of the coral communities. We found strong latitudinal and geographic gradients in coral community structure and composition that supports the presence of a high coral cover and diversity area that harbours temperature-sensitive taxa in the northern Mozambique Channel between Tanzania, northern Mozambique and northern Madagascar. Coral communities in the more northern latitudes of Kenya, Seychelles and the Maldives were generally composed of fewer bleaching-tolerant coral taxa and with reduced richness and diversity. There was also evidence for continued declines in the abundance of temperature-sensitive taxa and community change after 2004. While there are limitations of our regional dataset in terms of spatial and temporal replication, these patterns suggest that large-scale interactions between biogeographic factors and strong temperature anomalies influence coral communities while smaller-scale factors, such as the effect of fisheries closures, were weak. The northern Mozambique Channel, while not immune to temperature disturbances, shows continued signs of resistance to climate disturbances and remains a priority for future regional conservation and management actions.

Climate and small scale factors determine functional diversity shifts of biological soil crusts in Iberian drylands

Understanding functional diversity is critical to manage and preserve biodiversity and ecosystem functioning in the face of global change. However, the efforts to characterize this functional component have been mostly directed to vascular vegetation. We sampled lichen-dominated biological soil crusts (BSCs) in semiarid grasslands along an environmental gradient in the Iberian Peninsula. We characterized five effect functional traits for 31 lichens species, and evaluated the influence of large scale (i.e. precipitation) and small scale factors (i.e. substrate type, shrub presence, Stipa tenacissima presence) on dominant trait values; i.e. community weighted means, and functional divergence; i.e. Rao quadratic entropy in 580 sampling quadrats. Across the gradient, we found multiple trait shifts and a general increase of functional divergence with increasing precipitation. We also observed that substrate type and small scale biotic factors determined shifts in all traits studied, while these factors affected less to functional divergence. Comparing functional diversity with taxonomic diversity, we found contrasting responses to both large and small scale factors. These findings suggest that BSC community trait composition is influenced by multi-scale abiotic and biotic factors with environmental filtering dominating at large spatial scales and limiting similarity at specific small scales. Also, our results emphasize the potential differences between taxonomic and functional diversity in response to environmental factors. We concluded that functional diversity of BSCs not only provides novel and critical knowledge of BSC community structure, but also it should be considered as a critical tool in biodiversity conservation strategies, ecosystem services assessment and ecological modelling.

Static Pull-in Analysis of Capacitive FGM Nanocantilevers Subjected to Thermal Moment using Eringen’s Nonlocal Elasticity

This paper aims to investigate the pull-in phenomenon of functionally graded (FG) capacitive nanocantilevers subjected to an electrostatic force and thermal moment due to an applied voltage and thermal shock considering intermolecular force within the framework of nonlocal elasticity theory to account for the small scale effect. The FG nano-beam is made of mixture of metal and ceramic which the material properties vary continuously through the thickness according to an exponential distribution law (E-FGM). The nonlocal elastic behavior is described by the differential constitutive model of Eringen, which enables the present model to become effective in the analysis and design of nanosensors. The nano-beam is modeled assuming the Euler–Bernoulli beam theory and the equations are derived using the equilibrium of an element. A Galerkin-based step by step linearization method has been used to solve the governing static deflection equation. The present solution is validated with existing results reported in previous studies. The effects of temperature change, Van der Waals (VdW) or Casimir force and small scale factor on the five types of FG nano-beams are discussed in detail. The results indicate that VdW/Casimir force and thermal moment reduce the pull-in voltage, however, on the contrary, small scale effect cause to slightly increase the amount of pull-in voltage.

A class of transient acceleration models consistent with Big Bang cosmology

Is it possible that the current cosmic accelerating expansion will turn into a decelerating one? Can this transition be realized by some viable theoretical model that is consistent with the standard Big Bang cosmology? We study a class of phenomenological models with a transient acceleration, based on a dynamical dark energy with a very general form of equation of state pde = βρde − βρdem. It mimics the cosmological constant ρde → const for a small scale factor a, and behaves as a barotropic gas with ρde → a−3(α+1) with α ≥ 0 for large a. The cosmic evolution of four models in the class has been examined in detail, and all yield a smooth transient acceleration. Depending on the specific model, the future universe may be dominated by either dark energy or by matter. In two models, the dynamical dark energy can be explicitly realized by a scalar field with an analytical potential V(φ). Moreover, a statistical analysis shows that the models can be as robust as ΛCDM in confronting the observational data of Type Ia supernovae, cosmic microwave background (CMB) and baryon acoustic oscillation. As improvements over previous studies, our models overcome the problem of over-abundance of dark energy during early eras, and satisfy the constraints on dark energy from WMAP observations of CMB.

Bayesian hierarchical modeling of larval walleye (Sander vitreus) abundance and mortality: Accounting for spatial and temporal variability on a large river

Larval fish are extremely variable in space and time while sampling of populations is generally restricted and incomplete. However, estimates of abundance and mortality are important for understanding population dynamics, habitat quality, and anthropogenic impacts. Acknowledging and addressing variability during sampling and data analysis are imperative to producing informative estimates. A combination of spatially and temporally distributed ichthyoplankton sampling and Bayesian hierarchical and state-space modeling was used to partition variance and estimate abundance and mortality of larval walleye (Sander vitreus) in the Maumee River during 2010 and 2011. System variability and degree of sampling coverage have a direct impact on the quality of abundance estimates. Small scale factors (i.e., within site and day-to-day) accounted for the most variation in larval walleye densities, therefore sampling should concentrate on capturing these sources. Bayesian state-space modeling can improve estimates by sharing information through time, properly accounting for uncertainty, and producing probability distribution based estimates. Larval fish are highly variable and difficult to sample; however, the application of Bayesian methods during the data analysis process can lead to improved estimates of abundance and informed management actions.

Quantifying Spatial Genetic Structuring in Mesophotic Populations of the Precious Coral Corallium rubrum

While shallow water red coral populations have been overharvested in the past, nowadays, commercial harvesting shifted its pressure on mesophotic organisms. An understanding of red coral population structure, particularly larval dispersal patterns and connectivity among harvested populations is paramount to the viability of the species. In order to determine patterns of genetic spatial structuring of deep water Corallium rubrum populations, for the first time, colonies found between 58–118 m depth within the Tyrrhenian Sea were collected and analyzed. Ten microsatellite loci and two regions of mitochondrial DNA (mtMSH and mtC) were used to quantify patterns of genetic diversity within populations and to define population structuring at spatial scales from tens of metres to hundreds of kilometres. Microsatellites showed heterozygote deficiencies in all populations. Significant levels of genetic differentiation were observed at all investigated spatial scales, suggesting that populations are likely to be isolated. This differentiation may by the results of biological interactions, occurring within a small spatial scale and/or abiotic factors acting at a larger scale. Mitochondrial markers revealed significant genetic structuring at spatial scales greater then 100 km showing the occurrence of a barrier to gene flow between northern and southern Tyrrhenian populations. These findings provide support for the establishment of marine protected areas in the deep sea and off-shore reefs, in order to effectively maintain genetic diversity of mesophotic red coral populations.