Particle Size Distribution Models for Metallurgical Coke Grinding Products

Six different particle size distribution (Gates–Gaudin–Schuhmann (GGS), Rosin–Rammler (RR), Lognormal, Normal, Gamma, and Swebrec) models were compared under different metallurgical coke grinding conditions (ball size and grinding time). Adjusted R2, Akaike information criterion (AIC), and the root mean of square error (RMSE) were employed as comparison criteria. Swebrec and RR presented superior comparison criteria with the higher goodness-of-fit and the lower AIC and RMSE, containing the minimum variance values among data. The worst model fitting was GGS, with the poorest comparison criteria and a wider results variation. The undulation Swebrec parameter was ball size and grinding time-dependent, considering greater b values (b > 3) at longer grinding times. The RR α parameter does not exhibit a defined tendency related to grinding conditions, while the k parameter presents smaller values at longer grinding times. Both models depend on metallurgical coke grinding conditions and are hence an indication of the grinding behaviour. Finally, oversize and ultrafine particles are found with ball sizes of 4.0 cm according to grinding time. The ball size of 2.54 cm shows slight changes in particle median diameter over time, while 3.0 cm ball size requires more grinding time to reduce metallurgical coke particles.

Saudi Undergraduate Computing Programs in Light of the 2020 Curricula Report

University undergraduate pro- grams in computing disciplines are updated regularly to adapt to advancements in the field and emerging, fast-growing industry demand. This paper reports the current status of a selected set of undergraduate programs in com- puting fields in Saudi Arabia and compares them to other programs from international universi- ties in light of the 2020 Computing Curricula Report (CCR). This comparative study aims to enlighten future efforts for designing cur- ricula and updating undergraduate computing programs in Saudi Arabia. A sample of 26 Saudi universities (15 public and 11 private) and 15 international universities offering 161 programs is selected. The comparison criteria include program discipline, duration, number of units, accreditation, required training, and others. We find significant differences between programs offered by Saudi public and private universities compared to international university programs. For example, programs offered by Saudi universities, especially the public, require more units compared to international programs (median of 143 units vs. 120 units). Our findings would guide future undergraduate computing program developments in Saudi Arabia.

Integral Comparison Criteria for Half-Linear Differential Equations Seen as a Perturbation

In this paper, we present further developed results on Hille–Wintner-type integral comparison theorems for second-order half-linear differential equations. Compared equations are seen as perturbations of a given non-oscillatory equation, which allows studying the equations on the borderline of oscillation and non-oscillation. We bring a new comparison theorem and apply it to the so-called generalized Riemann–Weber equation (also referred to as a Euler-type equation).

RESEARCH OF THE ISSUES OF IMPROVEMENT OF PROTECTION SYSTEMS AGAINST DDOS-ATTACKS BASED ON THE COMPREHENSIVE ANALYSIS OF MODERN INTERACTION MECHANISMS

The article presents the results of an analysis of the growth in the development of botnet networks and new cyber threats when they are used by cybercriminals. A review and comparison of the models for the implementation of botnet networks is carried out, as a result of which there are two main types. The main types of attacks carried out using the infrastructure of distributed computer networks are identified and classified, formed into 7 main groups, taking into account the relevance, prevalence and amount of damage. Based on the results of the analysis, it was determined that the most widespread and relevant type of attack is “Denial of Service”. The article presents a classification of services that provide services to ensure the protection of network resources from distributed attacks by the "Denial of Service" type, by the type of deployment, the level of security and the types of services provided. The comparison criteria are given taking into account their infrastructure, availability of technical support and a test period, available types of protection, capabilities, additional options, notification and reporting, as well as licensing. Practically implemented and shown a way to integrate the DDoS-Guard Protection service with an additional module at the application level, which made it possible to expand the methods of protection against DDoS attacks. Various modifications of the combined use of the module and the modified system make it possible to increase the expected level of detection and prevention of cyber - attacks.

Indices of Victimization in Minor Victims of Sexual Violence and Abuse

The article presents the results of a comprehensive psychological and psychiatric examination of 117 minor victims of sexual violence and abuse. A qualitative and quantitative analysis of cases of sexual violence and abuse against minors was used, depending on the degree of the victims ' ability to understand the nature and significance of the illegal sexual acts committed with them and to resist them. The comparison criteria are identified: the type of violence and abuse, the age of the victim, the presence of a mental disorder in the victim, and the features of interaction in the "victim – assailant" dyad. 4 groups of victims are described, which differ in the degree of understanding of the criminal situation and the ability to resist, and indicators of victimization and victim behavior of children and adolescents are highlighted. The prospects for future research are outlined, which can improve the effectiveness of expert conclusions and preventive measures.

Involvement of Moscow medical personnel in the mentoring system

The article is devoted to the study of real and prospective practice of mentoring. The information base was data from the questionnaire survey of the personnel of Moscow medical organizations, carried out in 2019. The scale and character of the involvement of medical personnel in the mentoring system were studied with regards to prospective and appropriate models. The need for introduction or expansion of mentoring was compared with the available personnel potential. It turned out that doctors and nurses are involved in various types of mentoring. These are additional training in the workplace, regulated by the management, initiative assistance to youth during their adaptation, and various forms of informal transfer of practical knowledge on a wide range of issues. The demand for mentoring turned out to be higher among doctors and in hospitals. A comparison of respondents who had a mentor and who did not had one, but needed, revealed a shortage of models beyond the standard adaptation. Three groups of respondents were compared: those who were already a mentor, who would agree to become a mentor, who did not want to become a mentor. The educational and qualification level, research activities, work experience in the specialty, specifics of providing medical care with the account of complexity and responsibility were the comparison criteria. The need to introduce or expand mentoring is recognized by many respondents, and the potential composition of mentors allows us to speak about the prospects for its development.

Aeroaocustic Numerical Analysis of the Vehicle Model

Understanding local phenomena connected with airflow around road vehicles allows to reduce the negative impact of transportation on the environment. This paper presents using numerical tools for Computational Fluid Dynamics (CFD) and Computational AeroAcoustic (CAA) calculation. As a model for simulation, simplified car geometry is used, which is known in the research community as an Ahmed body. The study is divided into two main parts: a validation process and a CAA analysis using the Ffowcs Williams–Hawkings (FW-H) analogy. Research is performed using k−ω Shear Stress Transport (SST) and the Large Eddy Simulation (LES) turbulence model. To compare results with other authors’ studies, three different comparison criteria are introduced: a drag coefficient for different velocities, characteristic flow structure, and velocity profiles. The CAA analysis is presented using colormaps and Fast Fourier Transformation (FFT). The methods used in this work allow visualizing the acoustic field around reference geometry and determining the frequency range for which the A-weighted sound pressure level is the highest.