Miracle-dz/UniFAR-FTUs huggingface dataset:
Performance evaluation and kinetic parameter analysis for static granular bed reactor (SGBR) for treating poultry slaughterhouse wastewater at mesophilic condition

Poultry slaughterhouses consume a substantial quantity of potable water during processing of live birds. Subsequently, high strength poultry slaughterhouse wastewater (PSW) is generated at different stages during poultry product processing. In this study, a Static Granular Bed Reactor (SGBR) was used to treat the PSW from a poultry processing facility in the Western Cape, South Africa. The performance of the SGBR was primarily evaluated for chemical oxygen demand (tCOD) removal with the kinetics of the treatment process for PSW being evaluated using both the Grau second-order and the modified Stover-Kincannon models to predict the effluent COD. The overall treatment efficiency averaged >80% when the SGBR was operated at steady state for 110 days' experimental trial. On the basis of the experimental results, the predicted values of the tCOD concentration using the Grau second-order and modified Stover Kincannon model were inconsistent with the experimental data indicating an insignificant correlation with predicted tCOD concentration being higher than the experimental data. The high variation between the modelled and experimental data based on both the Grau second order and modified Stover-Kincannon model was observed at higher organic loading rates when the reactor was fed with undiluted influent, phenomena attributed to tCOD entrapped inside the SGBR, especially during periods of clogging caused by the accumulation of suspended solids in the underdrain.
Review of artificial intelligence development, its impact and its challenges

The field of Artificial Intelligence, which started roughly half a century ago, has a turbulent history. In the 1980s there has been a major paradigm shift towards embodiment. While embodied artificial intelligence is still highly diverse, changing, and far from “theoretically stable”, a certain consensus about the important issues and methods has been achieved or is rapidly emerging. With the popularization of the Internet, permeation of sensor networks, emergence of big data, increase in size of the information community, and interlinking and fusion of data and information throughout human society, physical space, and cyberspace, the information environment related to the current development of artificial intelligence (AI) has profoundly changed. AI faces important adjustments, and scientific foundations are confronted with new breakthroughs, as AI enters a new stage: AI 2.0. The goals of this research article are to review and synthesize the literature about service quality delivery through Artificial intelligence, describe what is known about the topic, and develop an agenda for needed research.
Techno‐economic design optimisation of an interior permanent‐magnet synchronous motor by the multi‐objective approach

In engineering terms, it is always desirable to maximise the efficiency of the motor and to look the problem in economic viewpoint, minimisation of the weight and cost of the motor is required. As these two aspects are like two sides of a coin, it is usually aimed to acquire the best efficiency per weight and cost. As a result, the performance improvement of permanent-magnet synchronous motor (PMSM) has two sides: technical and economic. This study proposes a new approach for design optimisation of an interior PMSM (IPMSM) taking into account both technical performances and economic considerations. The selected rotor configuration is a good candidate for general purpose industrial applications. A multi-objective optimisation technique based on a new and efficient magnetic equivalent circuit of the motor is applied to obtain optimal motor parameters. A Pareto front composed of possible optimal solutions is provided. The best optimal solution is then selected using a k-means clustering algorithm. To verify the efficacy of the design optimisation, the performance characteristics of the optimal PMSM are compared by both the finite element simulations and the experiments. In the test setup, an 8-pole, 200-Watt, four-phase IPMSM with an optimised structure is prototyped where the results give agreeable accuracy.
High-resolution EEG mapping: an equivalent charge-layer approach

Brain electrical signal is one of the windows to understanding neural activities. Various high-resolution imaging techniques have been developed to reveal the electrical activities underneath the cortical surface from scalp electroencephalographic recordings, such as scalp Laplacian, cortical surface potential, equivalent charge layer (ECL) and equivalent dipole layer (EDL). In this work, we develop forward density formulae for the ECL and the EDL of neural electric sources in a 4-concentric-sphere head model, and compare ECL with EDL in theory, simulation and real evoked data tests. The results confirm that the ECL map may be of higher spatial resolution than the EDL map.
Frechet derivatives in inverse obstacle scattering

There is an error in theorem 2.1 of this paper, which shows a representation of the Fréchet derivative with respect to the boundary of the far field operator from scattering by obstacles with Robin boundary conditions. The boundary condition in equation (2.4) has to be replaced by where H denotes the mean curvature of the boundary. The error occurs in the derivation of equation (2.12). Therefore the proof of theorem 2.1 presented in this paper has to be modified on pages 376-7 along the following lines. For the surface integral we obtain This can be seen by considering a fixed point and a local parametrization , of with The perturbed boundary is then locally described by . We compute at the point U0 with and the orthonormality of the tangential vectors leads to We obtain This holds independently of the parametrization and uniformly on . With the estimates (2.10)-(2.12) we first see from (2.8) by a perturbation argument that tends to u in . This is well known: the scattered field depends continuously on the boundary, or in our notation FR is a continuous operator (cf Kress and Zinn (1992) for the Dirichlet problem). Therefore, with equation (2.8) the proof is completed by showing for all v. Since u' is a radiating solution of (2.3)-(2.4) we obtain from the boundary condition Now we proceed as in the paper with the only modification of adding the integral in any following computation of the sesquilinear form . This rectifies the proof. Reference Kress R and Zinn A 1992 On the numerical solution of the three-dimensional inverse obstacle scattering problem J. Comput. Appl. Math. 42 46-61
Three Dimensional Vortex Formation of a Finite-Span Synthetic Jet

The effects of different geometries and input parameters on the flow structures of a finite span synthetic jet are explored in quiescent flow experiments using stereoscopic PIV. Common geometrical parameters, such as neck height, and orifice aspect ratio are varied along with the jet performance characteristics such as Strouhal numbers and Reynolds numbers. Orifice neck heights of 2, 4 and 6mm were tested at aspect ratios of 6, 12, and 18. Jet Strouhal numbers of 0.115 to 0.157 were tested at Reynolds numbers of 615. It is found that as the aspect ratio was increased the size of the vortical structures decreases, the vorticity dissipation rate increases, and axis switching occurred farther away from the orifice. The neck length had a large effect on the structures’ size and strength, their dissipation rate, and the jet’s spreading. Moreover, the driving frequency was found to affect the vortical structures spreading due to the streamwise spacing between structures, as well as drastically affecting dissipation of the structures in both planes.
Performance Analysis of DC-DC Buck Converter for Renewable Energy Application

This paper presents the analysis of DC-DC buck converter for renewable energy application. Renewable energy resources mostly produce DC voltages that are used DC-DC converter to convert the DC voltage from one level to another level according to different applications. This DC-DC buck converter is used to step down the high level DC voltage to low level DC voltage. By varying the duty cycle, the performance of buck converter in term of its output voltage can be obtained and analysed. Simulations have been performed using PSIM and validated with hardware implementation. All of the results are recorded and showed that very low voltage can be produced using this topology.
Structure and Raman Spectroscopy of Nanocrystalline TiO2 Powder Derived by Sol-Gel Process

Nanocrystalline TiO2 powder was prepared by sol-gel process. The structures of the as-prepared and the TiO2 powder heat-treated at different temperatures were studied by thermogravimetric analyzer, differential thermal analysis, x-ray diffraction, and Raman spectra. As the powder was heat-treated at 350°C, it turned into tetragonal anatase structure. A structural transformation from anatase to rutile type occurred and the grains of the powder grew drastically when the powder was heat-treated at above 550°C. The structural transformation from anatase to rutile type completed at 750°C. The Raman spectra of TiO2 nanocrystalline powder were also studied.
Crystal optics elements in a coherent x-ray scattering experiment

We describe wave propagation from a partially coherent x-ray source taking into account the free-space wave propagation and the Bragg diffraction on a collimating crystal. We find conditions when the free-space propagation becomes irrelevant and the coherence length is given by the extinction length of the corresponding Bragg reflection. We show that a wide wavelength range can be retained if the collimating crystal is illuminated by a convergent beam. The increase of the coherence length by Bragg diffraction is demonstrated in a laboratory experiment on periodic surface gratings with different periods.
Anisotropy Kinematics Clarified through Regime Rrays Model

“So-called rays” in the anisotropy context are just to-line-loci-idealized energy transport channels (c.f. Cerveny 2001 p.28-30, p.103). They are (1) not traveltimes minimizing Fermat’s principle loci, (2) not pointwise Snell’s law conforming, (3) not direction-wise orthagonal to front tangent planes; (4) and, velocity or slowness magnitudes along loci directions differ from those in front-normal directions. All the understood attributes/characteristics of traditional rays, call those here “proper rays”, have been compromised through the inappropriate “so-called rays” labeling (likely from use initially in Rudzki’s lesser known 1913 paper).
An investigation of passive scalar transport in canopy turbulence using LDA and LIF

The problem of transport and diffusion of passive scalars in canopy sublayer (e.g. forests, urban canopies, vegetated channels) is of great interest in several fields. Although the main features of the flow field above and inside a dense canopy is now well understood (Finnigan, 2000; Raupach et al., 1996), the role of the principal vorticity (e.g. KelvinHelmholtz vorticity at the top of the canopy, KH, and von Karman vorticity inside the canopy, vK) in the transport and diffusion of passive scalar in canopy turbulence is still an open problem. In the present paper, Laser Induced Fluorescence (LIF) and Laser Doppler Anemometry (LDA) techniques are used simultaneously to study statistically the features of KH vorticity and their connection with the transport of passive scalar from above to inside a dense model canopy. Detailed measurements are presented for the mean velocity (U), turbulent intensity of longitudinal and vertical velocity fluctuation (u, v), Reynolds stress (uv ), and mean and fluctuation concentration intensity (C, c). We show that, through the accurate choice of fluorescent dye and source laser, it is possible to obtain sufficiently high quality joint statistics (uc and vc ) without adopting complicate techniques of acquisition. Using this technique a new and more detailed analysis, at least in a statistical sense, of the flow field inside the canopy sublayer is possible. In particular, we show that inside the canopy the PDF of the vertical and longitudinal velocity associated with the shedding vorticity is well described by a Gaussian distribution. Otherwise, the sweep events, associated with the instability of Kelvin-Helmholtz vorticity, exhibit a PDF of the velocity that is well described by a gamma distribution.
Delay-dependent asymptotic stability of mobile ad-hoc networks: A descriptor system approach

In order to analyze the capacity stability of the time-varying-propagation and delay-dependent of mobile ad-hoc networks (MANETs), in this paper, a novel approach is proposed to explore the capacity asymptotic stability for the delay-dependent of MANETs based on non-cooperative game theory, where the delay-dependent conditions are explicitly taken into consideration. This approach is based on the Lyapunov—Krasovskii stability theory for functional differential equations and the linear matrix inequality (LMI) technique. A corresponding Lyapunov—Krasovskii functional is introduced for the stability analysis of this system with use of the descriptor and “neutral-type” model transformation without producing any additional dynamics. The delay-dependent stability criteria are derived for this system. Conditions are given in terms of linear matrix inequalities, and for the first time referred to neutral systems with the time-varying propagation and delay-dependent stability for capacity analysis of MANETs. The proposed criteria are less conservative since they are based on an equivalent model transformation. Furthermore, we also provide an effective and efficient iterative algorithm to solve the constrained stability control model. Simulation experiments have verified the effectiveness and efficiency of our algorithm.
Semi-characteristic polynomials, {\phi}-modules and skew polynomials

We introduce the notion of semi-characteristic polynomial for a semi-linear map of a finite- dimensional vector space over a field of characteristic p. This polynomial has some properties in common with the classical characteristic polynomial of a linear map. We use this notion to study skew polynomials and linearized polynomials over a finite field, giving an algorithm to compute the splitting field of a linearized polynomial over a finite field and the Galois action on this field. We also give a way to compute the optimal bound of a skew polynomial. We then look at properties of the factorizations of skew polynomials, giving a map that computes several invariants of these factorizations. We also explain how to count the number of factorizations and how to find them all.
Dusty Nuclear Disks and Filaments in Early-Type Galaxies

We examine the dust properties of a nearby distance-limited sample of early-type galaxies using WFPC2 of the Hubble Space Telescope. Dust is detected in 29 out of 67 galaxies (43%), including 12 with small nuclear dusty disks. In a separate sample of 40 galaxies biased for the detection of dust by virtue of their detection in IRAS 100 μm band, dust is found in ∼78% of the galaxies, 15 of which contain dusty disks. In those galaxies with detectable dust, the apparent mass of the dust correlates with radio and far-infrared luminosity, becoming more significant for systems with filamentary dust. A majority of IRAS and radio detections are also associated with dusty galaxies rather than dustless galaxies. This indicates that thermal emission from clumpy, filamentary dust is the main source of the far-IR radiation in early-type galaxies. Dust in small disklike morphology tends to be well aligned with the major axis of the host galaxies, while filamentary dust appears to be more randomly distributed with no preference for alignment with any major galactic structure. This suggests that, if the dusty disks and filaments have a common origin, the dust originates externally and requires time to dynamically relax and settle in the galaxy potential in the form of compact disks. More galaxies with visible dust than without dust display emission lines, indicative of ionized gas, although such nuclear activity does not show a preference for dusty disk over filamentary dust. There appears to be a weak relationship between the mass of the dusty disks and central velocity dispersion of the galaxy, suggesting a connection with a similar recently recognized relationship between the latter and the black hole mass.
A Graphical Model for Shallow Parsing Sequences

[Intro] Probabilistic Models for sequence data can be mainly divided into two categories: I. Fairly sophisticated models that are aimed at finding an all encompassing characterisation of the whole sequence by the means of an interdependent generative process (such as PCFGs and HMMs); and II. Relatively simple models that make an independence assumption regarding the generation process of each of the elements of the sequence (such as Unigram, Naive Bayes, Clustering, PLSA and LDA). In this paper we explore the interval between these two extremes with a model that does not attempt to be a global characterisation of the sequence as in the case of PCFG/HMM but yet it does not assume independence among the generative processes of the subsequent elements in the sequence.
Product-Specific Nonlinear Characterization and Instrument for Illumination Angle Measurement With Manufacturing Defects

Popular sensors that detect the quadrant of the illumination directions are often inadequate for advanced control systems, e.g., solar trackers and heliostats. We propose a theoretical and technical framework for some sensor-specific characterization tools together with an optical instrument, which makes possible the accurate measurements in terms of the illumination angle and its angular velocity at the presence of the manufacturing errors due to rough manufacturing processes (e.g., forging and casting). In particular, a parameter identification approach is employed to identify four uncertain incline angles of sensor products with the aid of an ingenious and controllable calibration device. The angular velocity of illumination is approximately derived through a one-step backward difference function together with finite impulse response filters to reject the disturbances. The experimental results show that the sensor-specific nonlinear characteristic functions improve the accuracy of the illumination angle measurement yielded by the general nonlinear characteristic functions for the ideal sensors up to 96%, where the measurement precision with 0.07° is achieved.
Validating a Research Instrument: Diagnostic Test for First Year University of Technology Engineering Mathematics Students

Poor performances by first year engineering mathematics students at tertiary institutions in South Africa continue unabated due to a variety of reasons. It is sometimes assumed that the students entering a university have the necessary preliminary knowledge to proceed with the university curriculum. However, when we teach or assess students we find that students have gaps in their school knowledge. Identifying first year engineering students’ basic mathematical competencies and knowledge gaps have become a prime focus of many tertiary institutions in South Africa. Improving these mathematical skills early in the students’ studies is an onerous task. This paper reports on an e-learning research instrument designed for first year engineering students in mathematics. The research instrument was designed to identify areas of weaknesses and strengths thereby isolating ‘at risk’ students at an early stage of their first year mathematics course at a university of technology. The online test compiled of basic mathematics questions was peer reviewed and validated by mathematics lecturers from a mathematics department at a university of technology. Lecturers personally took the online test. A general questionnaire was completed and then each question analysed to ascertain its appropriateness. We found that there was consensus for the criteria of language clarity, question relevance, notation and terminology but discrepancies in cognitive levels. Validation of items in respect of clear language, appropriateness of the questions for the test as well as appropriate use of notation and terminology was confirmed
The retrieval of a buried cylindrical obstacle by a constrained modified gradient method in the H-polarization case and for Maxwellian materials

The retrieval of an unknown, possibly inhomogeneous, penetrable cylindrical obstacle buried entirely in a known homogeneous half-space - the constitutive material parameters of the obstacle and of its embedding obey a Maxwell model - is considered from single- or multiple-frequency aspect-limited data collected by ideal sensors located in air above the embedding half-space, when a small number of time-harmonic transverse electric (TE)-polarized line sources - the magnetic field H is directed along the axis of the cylinder - is also placed in air. The wavefield is modelled from a rigorous H-field domain integral-differential formulation which involves the dot product of the gradients of the single component of H and of the Green function of the stratified environment times a scalar-valued contrast function which contains the obstacle parameters (the frequency-independent, position-dependent relative permittivity and conductivity). A modified gradient method is developed in order to reconstruct the maps of such parameters within a prescribed search domain from the iterative minimization of a cost functional which incorporates both the error in reproducing the data and the error on the field built inside this domain. Non-physical values are excluded and convergence reached by incorporating in the solution algorithm, from a proper choice of unknowns, the condition that the relative permittivity be larger than or equal to 1, and the conductivity be non-negative. The efficiency of the constrained method is illustrated from noiseless and noisy synthetic data acquired independently. The importance of the choice of the initial values of the sought quantities, the need for a periodic refreshment of the constitutive parameters to avoid the algorithm providing inconsistent results, and the interest of a frequency-hopping strategy to obtain finer and finer features of the obstacle when the frequency is raised, are underlined. It is also shown that though either the permittivity map or the conductivity map can be obtained for a fair variety of cases, retrieving both of them may be difficult unless further information is made available.
A note on the creation of condensation nuclei by negative corona discharges in air at low pressure

The production of condensation nuclei by a negative point-plane corona discharge is discussed in the light of experimental results in which the occurrence of 'large' ions of low mobility, the concentrations of condensation nuclei and the identification of ionic species by mass spectrometer, have been separately studied. It is concluded that the nuclei occur mainly in the outer regions of the discharge.