Physical Science: New Insights and Developments Vol. 3

Fast Algorithm for Outlier Detection in Time Series: Finding a Solution with a Minimum Amount of Rejected Measurement Data

Igor V.Bezmenov — Mon, 10 Nov 2025 00:00:00 +0000

This study addresses the challenge of detecting coarse measurements (outliers) in time series data, a common issue in fields such as space geodynamics, geodesy, and other measurement-driven sciences. The proposed outlier detection algorithm solves two key problems: first, it finds a solution containing the maximum possible amount of measurement data remaining after detecting and removing outliers. Second, it requires the minimum possible number of arithmetic operations, estimated by the value O(NlogN), which cannot be improved in order N, to find a solution. To construct the algorithm, it was shown that the required solution should be sought in the ordered sequence of input data in the form of a set of consecutive numbers. The search for the set of maximum length is performed step by step, with the range of possible values of the set length being halved at each step. The transition to one of the two halves is performed by checking the fulfilment of certain criteria, not for all possible values of lengths from the range under consideration, but only for its mid value. Testing the algorithm on real data obtained from laser rangefinder measurements showed the advantages of it over others, both in terms of time consumption and the amount of data remaining after detection and removal of outliers. The algorithm is robust and always finds a solution, if one exists. Its time efficiency is evident when cleaning a large amount of measurement data of outliers. It can be used for automated cleaning from outliers of observation data in information and measuring systems, in systems with artificial intelligence, as well as when solving various scientific, applied managerial and other problems using modern computer systems in order to obtain promptly the most accurate final result.

Thermal and Energy Performance Analysis of a Locally Designed Optimised Roasting Oven

Mon, 10 Nov 2025 00:00:00 +0000

In many developing countries, biomass is the main source of energy used for cooking. In Burkina Faso, 90.1% of households use solid fuels (wood and wood products) as their main source of cooking energy, and this situation is not expected to change significantly in the coming decades. This high degree of dependence has a negative impact on forest resources. The present work concerns an experimental study of the energy performance of a prototype optimised oven developed by local craftsmen. The Water Boiling Technique (WBT) is the method used to evaluate the energy efficiency of the oven. The temperatures of the oven’s walls and the ambient temperature were measured to evaluate energy losses by convection into the environment. The oven's heat balance was used to determine the amount of energy lost through the smoke. The energy generated by combustion (Q_B) is calculated by taking a mass balance of the fuel (wood or butane gas, depending on the oven) before and after each experiment to obtain the mass of fuel consumed (Mc). The results showed that a large amount of thermal energy is lost through the smoke (50% of the energy generated by gas combustion). Losses through the walls were reduced to 8%. The oven's efficiency reached 42%. This is in line with the standard efficiency of optimised gas ovens (between 40 and 50%). External wall temperatures remain below 60°C, ensuring user safety and improved thermal comfort. The results show the need to optimise the oven by conducting work to reduce heat losses through smoke.

Rotational Energy for Estimating Flow Swirl Intensity

N. E. Shishkin — Mon, 10 Nov 2025 00:00:00 +0000

The intensity of flow swirl is a crucial parameter that affects heat and mass transfer processes. However, the widely used Chigier and Beer integral parameter is not universal and has certain limitations, particularly in cases of strong swirl and the appearance of return flows or weak axial flows such as those found in vortex chambers.

The present study proposes a criterion for estimating the intensity of flow swirl using the Mach number for the rotational component of velocity at specific points. Flow self-similarity along both channel radius and length has been investigated for a wide variety of conditions. The study also analyses the sharp decrease in the maximum value of the criterion during the propagation of submerged jets in a tube and in the case of mixing in a confined swirl flow. The proposed approximating dependencies describing the decrease in swirl intensity were obtained based on experimental works of different authors.

The experimental data were generalised using the asymptotic approach of the Kutateladze–Leontiev film cooling theory by applying the analogy of the criterion with the distributions of the dimensionless temperature along the channel radius and length.

Triple-shock Configurations, Complex Vortices, and Instabilities in High-speed Flows of Gaseous Media Containing External Energy Sources

O. A. Azarova, L. G. Gvozdeva — Mon, 10 Nov 2025 00:00:00 +0000

Supersonic flow control using energy deposition in different places in the flow and on an AD body’s surface has been widely researched in modern aerospace engineering. A key area of interest is the control of triple-shock configurations and vortex structures, which significantly affect the aerodynamic and thermal loads on bodies in high-speed flows. In this chapter, the problem of supersonic streamlining AD body, “a plate blunted by a cylinder” by a flow with the freestream Mach number M=4 containing an external energy source, was numerically studied, taking into account physical-chemical transformations. The results of the effect of the specific heat ratio $\gamma$ changing in the range from 1.1 to 1.4 on the dynamics of triple-shock configurations and vortex-contact structures are presented for the interaction of an energy source with the bow shock wave. The energy source is modelled via the heated rarefied layer (filament). The angles in triple-shock configurations, the stagnation pressure, and the drag force were investigated as functions of the specific adiabat ratio γ, the characteristics of the energy source, and the incident shock angle. Vortex-contact structures were researched for the Mach numbers 7, 8, and 9. Generation of the Richtmyer-Meshkov instability accompanying the formation of a triple-shock configuration was obtained. The results showed a strong influence of the specific heat ratio of the gas medium and the parameters of the energy source on the triple-shock configuration and aerodynamic characteristics of the body. The obtained results may be of interest for aerospace applications in the field of designing nozzles, air intakes and high-speed aircraft, as well as designing control systems for flights in the atmospheres of other planets using external energy supply.

De-Risking the Atom: An Integrated Framework of Economic Incentives and Legislative Reforms for Nuclear Energy Deployment in Nigeria

EZREL TABIOWO — Mon, 10 Nov 2025 00:00:00 +0000

Nigeria's ambitious energy transition and economic development goals are critically hampered by a pervasive energy deficit and an over-reliance on volatile fossil fuels. While nuclear power presents a compelling solution for delivering stable, low-carbon baseload electricity, its historical challenges (prohibitive capital costs, complex risk profiles, and stringent regulatory demands) have stalled its adoption across emerging economies. This study addresses a critical gap in the literature by moving beyond technical feasibility studies to propose a holistic, Nigeria-specific framework that synergistically combines innovative economic models, targeted legislative incentives, and robust risk mitigation strategies to de-risk nuclear investments. Through a mixed-methods approach involving systematic literature review, comparative policy analysis, and preliminary economic modelling, the study evaluates the fundamental economic determinants of nuclear viability within Nigeria's unique context. It identifies the high cost of capital, driven by perceived risks, as the primary barrier. A quantitative analysis shows that with a weighted average cost of capital (WACC) reduced from a risky 12% to a de-risked 8%, the Levelized Cost of Electricity (LCOE) for nuclear power in Nigeria could fall from approximately $102/MWh to a competitive $72/MWh. Consequently, the chapter prescribes a detailed framework encompassing financial instruments like tax credits and sovereign guarantees, legislative reforms for regulatory certainty, and layered risk-sharing mechanisms. The analysis concludes that nuclear energy's economic viability in Nigeria is not intrinsic but can be engineered through deliberate policy and legislative action. The chapter advocates for a phased strategy, prioritising Small Modular Reactors (SMRs), and provides a concrete, actionable roadmap for policymakers to translate nuclear ambition into tangible, bankable projects.

A Study on Hypergeometric Solutions to Nonhomogeneous Equations of Fractional Order

Jorge Olivares, Pablo Martin, Fernando Maass — Mon, 10 Nov 2025 00:00:00 +0000

The study addresses the solution of a nonhomogeneous linear differential equation of fractional order α, equal to the modified Bessel function of order zero (I₀(x)), under the initial condition (f(0) = 0) and with (0 < α < 1). The Caputo definition of the fractional derivative is adopted, which is widely used in the analysis of physical and chemical phenomena such as viscoelasticity, anomalous diffusion, and electrical circuits. By means of the Laplace transform and its inverse, analytical solutions are obtained for the specific cases (α = 1/4, 1/2, 3/4), expressed in terms of hypergeometric functions ₂F₁. These solutions combine a fractional power of the independent variable (x) with a special function, reflecting the non-integer nature of the differential operator. Furthermore, regular patterns are observed in the parameters of the hypergeometric functions as α varies, suggesting a generalizable structure for other fractional values. The work demonstrates that fractional differential equations can be systematically solved using classical tools of integral and transform calculus, connecting fractional derivatives with families of special functions.

Introducing A New Method to Obtain Analytic Approximations of the Bessel Function $J_1$(x)

Pablo Martin, Fernando Maass — Mon, 10 Nov 2025 00:00:00 +0000

The power series of $J_1$(x) is well known and its convergence radius is infinite. In this work, an analytic approximation for $J_1$(x) has been found, which is simple and precise, and good for most of the applications of these functions in Physics. Two techniques have been used here, and the simplest approximant is a function of four parameters. The technique used here resembles a little the Pade method, since rational functions are used, but now this type of function is combined in an efficient way with elementary functions. Furthermore, series power and asymptotic expansions are used simultaneously, as in the Multipoint Quasi-rational Approximation MPQA method. However, here important improvements have been introduced. Though the form of the approximate is built considering the above two expansions, however the parameters of the approximations are determinates by two methods, one similar to the minimum square error method and the other using the coefficients of two expansions, power and asymptotic. The resulting approximations are very simple yet achieve high accuracy, sufficient for most physical applications of $J_1$(x). Better results are obtained with the first procedure.

Control of the Shape and Position of a Bow Shock Wave, Drag and Lift Forces, and Self-Sustained Flow Pulsations Using Stratified Energy Supply

O. A. Azarova — Mon, 10 Nov 2025 00:00:00 +0000

In this study, a method for controlling high-speed flows using a continuously acting thermally stratified energy deposition is presented. The study analyses the dependence of the shape and position of a bow shock wave, drag and lift forces, and self-sustained flow pulsations on the temperature values in the layers of a stratified energy source acting on an aerodynamic body. Numerical modelling is based on the system of the Navier-Stokes equations for viscous heat-conducting gas (air) at freestream Mach number M_∞=2. A detailed visualisation of the dynamics of the density, pressure, temperature, and local Mach number fields during the controlled establishment of steady-state flow regimes is presented. Multiple manifestation of the Richtmyer–Meshkov instability is demonstrated. Sharp peaks accompanying the development of Richtmyer–Meshkov instabilities are observed. These peaks persist even in the steady-state flow regime established under the action of stratified energy supply, changing the shape of the bow shock wave and giving it a wavy form. Basic approaches to controlling the shape and position of the bow shock wave, drag, and lift (pitch) forces (at zero angle of attack), as well as stability in steady-state supersonic flow past an aerodynamic body, have been developed using a continuously operating thermally stratified energy deposition. The possibility of generating and damping self-sustaining flow pulsations, as well as the formation of a steady flow with opposing, continuously acting lift forces, is demonstrated by changing the temperature in the layers of the thermally stratified energy source. The practical application of the developed methods for control of the characteristics and stability of high-speed flow/flight can be associated with the development of non-mechanical control systems for aircraft at the stage of echelon (horizontal) flight.