A gradient boosting machine learning approach in modeling the impact of temperature and humidity on the transmission rate of COVID-19 in India

Applied Intelligence - Meteorological parameters were crucial and effective factors in past infectious diseases, like influenza and severe acute respiratory syndrome (SARS), etc. The present study...     

Using GIS, Genetic Algorithms, and Visualization in Highway Development

A model for highway development is presented, which uses geographic information systems (GIS), genetic algorithms (GA), and computer visualization (CV). GIS serves as a repository of geographic information and enables spatial manipulations and database management. GAs are used to optimize highway alignments in a complex search space. CV is a technique used to convey the characteristics of alternative solutions, which can be the basis of decisions. The proposed model implements GIS and GA to find an optimized alignment based on the minimization of highway costs. CV is implemented to investigate the effects of intangible parameters, such as unusual land and environmental characteristics not considered in optimization. Constrained optimization using GAs may be performed at subsequent stages if necessary using feedback received from CVs. Implementation of the model in a real highway project from Maryland indicates that integration of GIS, GAs, and CV greatly enhances the highway development process.     

No time for crime? The effect of compulsory engagement on youth crime

This paper examines the potential incapacitation effect on various categories of crime committed by young persons. I exploit the increase in compulsory education-work participation age from 15 to 17 in Australia's largest state. The policy primarily increased participation in schools with high enrolments in school-based vocational education programs. By using incidents of crime, I incorporate incapacitation effects on crimes that do not lead to arrests and provide net effect of the policy. Results show substantial reduction in incidents of crime, particularly by male offenders in urban areas and suggest that the policy did not displace crime from streets to schools. Crimes against property, which are often diverted from the criminal justice system, show the largest decline.     

Spectrophotometric studies of rice bran oil and mustard oil mixtures: II

Visible spectra, between 400 to 500 nm range, of rice bran oil, mustard oil and their 7 mixtures, diluted 10 times in carbon tetrachloride, are reported. Mustard oil spectra shows three characteristic bands centered at wavelength 428, 453 and 482 nm, while no such band has been observed in rice bran oil spectra in this range. Intensity of 428 nm band increases as the rice bran oil percentage increases in the mixture of two oils. Five indices, R₁ to R₅, have been suggested for the approximate determination of rice bran oil adulteration in mustard oil. Plots of R₂ and R₃ against percentage of rice bran oil in the mixture have been found to be straight lines. The index R₃, equal to 1000(A₄₂₈-A₄₈₂), has been found to be the most useful for this approximate estimation of rice brain oil in mustard oil.     

Computer-aided roll pass design for continuous billet mill

A mathematical model has been developed for computing the geometrical dimensions of square-diamond square pass sequence for a continuous billet mill. The model is based on derivation of shape and size factor from the geometry of the pass taking into account pass filling, pass rounding etc. Using these factors and a basic equation of spread for flat rolling, a governing equation incorporating angle of diamond and reduction in consecutive passes has been formulated. Newton’s substitution method has been used to solve the equation. With known reduction between consecutive passes, geometrical dimension of square and diamond passes are computed. A model has been used to calculate pass design of a finishing train of a continuous billet mill producing 60 mm square billet from 120 mm square bloom. The elongation values have been optimized by varying the apex angle of diamond. A close agreement between computed and actual values shows the validity of the model.     

Properties of composites of 2014 aluminium alloy with Ni-Mo-based metallic glass particles

Composites of 2014 aluminium alloy containing dispersions of metallic glass particles (51.5wt% Ni, 38.0wt% Mo, 8.0wt% Cr and 1.5wt% B) have been prepared by a conventional powder metallurgy route involving powder mixing, compaction, sintering and heat treatment. Physical and mechanical properties of the composites, such as dimensional changes, hardness, electrical resistivity and corrosion behaviour, were studied. Dimensional growth up to a maximum of 6% in a linear direction was observed in all sintered composites. HardnessHv increased from 40 to 55kgmm^–2 with the addition of 4vol% of dispersoid, followed by a gradual decrease with increasing additions of dispersoid. The decrease in hardness above 4vol% of dispersoid was attributed to the presence of increasing amounts of porosity. Electrical resistivity increased from 50nm (for 2014 aluminium alloy) to 180nm at 20vol% dispersoid. The corrosion rate in an artificial sea water environment decreased linearly with the volume fraction of dispersoid. Re-pressing and re-sintering (in an argon atmosphere) of composites containing 4vol% of metallic glass particles resulted in an increase inHv from 55 (argon sintering) to 83kgmm^–2, and a decrease in electrical resistivity from 57 to 52nm due to the increase in density. The corrosion rate in an artificial sea water environment of composites containing 4vol% of metallic glass decreased from 70×10^–3 to 50×10^–3 mgdm^–2 per day due to re-pressing and re-sintering.     

The role of stably stratified fluid and anisotropy porous medium in modeling fluid flow through an asymmetrically heated/cooled vertical annulus

In this article, the natural convection of stratified fluid driven by the asymmetric heating and cooling of the surfaces of the concentric cylinders filled with an anisotropic porous matrix is investigated. The stratified fluid is confined between the outer surface of the inner cylinder and the inner surface of the outer cylinder while the onset transient natural convection is induced by the asymmetric heat heating/cooling of the inner surface of the outer cylinder while the outer surface of the inner cylinder is maintained at a constant temperature $T=1$. The present problem is governed by a pair of coupled second-order partial differential equations. To obtain the expressions for the temperature and velocity fields, the coupled mathematical equations describing the problem are systematically uncoupled such that their original orders remain unaltered. The research established that if the temperature of the outer surface of the inner cylinder equals the temperature of the inner surface of the outer cylinder, a symmetric flow occurs where two maxima velocities are observed close to the surfaces $Z=1$ and $\lambda$ of the annulus, respectively. Furthermore, for some constraints on certain values of some physical quantities in the flow solutions, the present work excellently compares with the research conducted by Jha and Oni.     

Time-dependent natural convection fluid flow of stably stratified fluid in an asymmetrically heated vertical channel filled with an anisotropic porous material

This paper presents a theoretical analysis of the combined effects of anisotropic porous material and thermal stratification on the transient natural convection fluid flow in an asymmetrically heated vertical parallel channel. The solutions of the governing equations for the temperature and velocity fields are obtained using Laplace transform technique, Riemann sum approximation, and the D'Alembert method. The choice of the D'Alembert method is to provide a simple decoupling procedure for the coupled governing equations while still retaining their original orders. The research established that owing to the layering effect induced by the thermal stratification $(S)$, the temperature and the velocity distributions of the fluid are found to be attenuated with an increase in thermal stratification. It is also observed that the inclusion of anisotropic parameters in the transport equations aids in regulating the fluid velocity, temperature, Nusselt number, skin friction, and mass flow rate. In addition, by neglecting the anisotropic parameter and taking into account the adiabatic stratification of the fluid, the numerical values for the mass flow rate of the present research favorably compared with the numerical results obtained by Singh et al.     

Time-dependent pressure-driven flow in a horizontal cylinder filled with a bidisperse porous material

Some properties of time-dependent that modify Brinkman equations for fluid flow in a cylindrical tube filled with Bidisperse Porous Material are discussed in this article. The fluid velocities through the fracture and porous phases of the Bidisperse Porous Medium (BDPM) resulting from the application of pressure gradient are described by two coupled second-order partial differential equations. Laplace transform technique, D'Alembert and Riemann-Sum Approximation Methods are used to obtain a semianalytical solution for the model. The choice of the D'Alembert is made to systematically decouple the coupled governing equations without altering their initial orders. The role of the coupling parameter: The coefficient of momentum transfer $(\eta )$ in the flow formation is considered. Accordingly, three cases are analyzed: (a) weak coupling $(\eta =0)$ which described the fluid flow in the absence of the coupling parameter, (b) the strong coupling resulting from a large value of the coupling parameter $(\eta \to \infty )$, and (c) fluid momentum for any arbitrary value of $\eta$. It is observed that fluid stability is attained when ${\mathit{Da}}_f$ and ${\mathit{Da}}_p$ are decreased; a finding that agrees with the findings of Nield and Kuznetsov and Magyari. Also, the maximum velocity in the fracture phase of the BDPM is attained when the coefficient of momentum transfer is neglected $(\eta =0)$ while an opposing flow formation is demonstrated in the fracture and porous phases of BDPM as $\eta$ is increased.