bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of biotechnology for cultivating Potentilla L. plant material with antivirus and antibacterial activity
Authors: Tikhomirova L I , Zaripova AA 
Published: December 2020

Abstract
The reported paper presents a biotechnology developed to produce phytomass of Potentilla L. species (P. alba, P. fragarioides, P. fruticosa, P. chrisantha, P. longifolia). Regenerative Potentilla plants are good at extracting bio-friendly elements (Pb, Cu, and Zn) from the Murashige and Skoog growth medium and accumulating them.
Water extracts of plant material P. alba, P. fragarioides, P. fruticosa, P. chrisantha, P. longifolia have shown a good biological activity against herpes simplex virus type II. Extracts of bio-technologically produced Potentilla alba plants have demonstrated an antibacterial activity against E. coli, K. pneumoniae, S. typhimurium, St. aureus taken in a minimal dose of 37.5 μg/ml.
Role of metrology inaccuracy for variance of test results under reproducibility conditions
Authors: Zakhakhatnov V.G. , Popov V.M. , Afonkina V.A. , Levinsky V.N. 
Published: December 2020

Abstract
A source of inaccuracy in regression models is supposed to be the statistical nature of a model and metrology inaccuracy related to the measuring explanatory and response variables. A number of approaches to the assessing inaccuracy of regression models are available. However, their use in searching for a solution to engineering problems concerning the assessing multiple regression inaccuracy is restricted by insufficiently developed mathematical tools. When explanatory variables assigned appropriately the inaccuracy of a regression depends on the reproducibility of test results. The reported simulation study investigates the importance of a measurement error to the variance of a normally distributed random variable for small sample sizes between 2 and 30 and coefficients of variation 1, 2, 10, 20, 40, 60. The effect of inaccuracy is analyzed relying on a relative confidence interval of variances estimated as a difference between variance intervals for a variable measured inaccurately and accurately divided by a confidence interval of the variance for an accurately measured variable. The outcomes to emerge from the study are quantity-related estimates for the effect of metrology inaccuracy in the measuring random variables with various coefficients of variation for small sample sizes and different relative measurement errors. For the assessing we use 106 retests and a maximal variance for the same number of repeated tests. The results make possible to evaluate an effect of metrology inaccuracy for diverse coefficients of test results variation, as well as determine an appropriate extent of testing for assigned model inaccuracies and a known measurement error. In addition, practical application of obtained results is shown.
Electrically Energized Comfort Heating System Based on Electric Film Heaters and intended for Post-Weaned Pigs
Authors: Popov V M , Afonkina V A , Epishkov E N 
Published: December 2020

Abstract
The reported paper summarizes outcomes of the thesis “Electrically energized comfort heating system intended for pre-nursery pigs kept in an unheated sow house” [2]. This alternative method of keeping warm pre-nursery pigs has been proven to be efficient both in the pilot phase and in pilot batch production. The further research aimed at the application of this system to the keeping warm pre-weaned pigs. The paper describes and presents a calculation procedure for parameters of a comfort heating system based on film heaters and intended for pre-weaned pigs.
Formation of a digital transformation system for the transport complex
Authors: Tolkachev S A , Morkovkin D E , Shcherbachenko P S , Gibadullin A A , Bykov A A 
Published: December 2020

Abstract
The presented study is devoted to assessing the level of digital development of organizations and the formation of a digital transformation system for the transport complex. The digital transformation of the transport complex is considered in the framework of the concept of the cyclic sequence of the spread of basic technologies in the economy, in accordance with which the full-scale deployment of the “transport” technological structure is predicted within the framework of the third mega technological cycle in the middle of the 21st century. The study analyzed indicators reflecting the level of digital development of organizations, transport companies and the amount of data protection tools used. Because of the analysis, it was revealed that in general, organizations have a high share of digitalization, but they are significantly lower in organizations of the transport complex, while about a third of organizations do not use data protection technologies. The study proposed a model for providing digital transformation of the transport complex, containing the types of activities that should be involved in digital transformation, the potential used for digital transformation and tools for digital transformation of the transport complex. In conclusion, conclusions were drawn from the results of the study.
A model of the effect of dry friction on the behaviour of a dynamical system
Authors: Ciornei F-C , Alaci S , Bujoreanu C 
Published: December 2020

Abstract
A dynamical system with one degree of freedom is modelled in two manners: the first one considers that only the dynamical sliding friction is present and the second considers the presence of both dynamic friction and static friction. It is difficult to apply the model of revealed static friction only for the zero relative velocity. For this reason, an approximate model for the static friction was identified, that accepts that the static friction occurs when the magnitude of relative velocity in contact decreases under a certain value, the critical value. The integration of the equations of motion of the two models reveals that for important values of the relative velocity, the two models estimate the same behaviour of the system. An experimental set-up was used to validate the theoretical results.
Reconfigurable multilayers architecture used as electromagnetic sensor
Authors: Iftimie N , Steigmann R , Dobrescu G S , Danila N A , Stanciu M D , Faktorova D , Savin A 
Published: December 2020

Abstract
The models designed CAD/CAM were loaded into the simulator to analyze the characteristics of the experimental devices attached. The array of sensors with unconventional architecture with reconfigurable unit cells (UCs) was topologically optimized, establishing the opening angle of the cell, the active surface, the geometry of the structure of the areas starting from the idea that the resonance frequency should be within the range of ISM frequencies. The simulations and determinations of test parameters of UC geometry are used for realization of arrays with reconfigurable shapes having the same aperture angle that can be used as wireless sensors for pressure detection.
Analysis of the collapse mode classification in case of circular tubes
Authors: Predoiu C P , Negrea R F , Tabacu S , Popa D 
Published: December 2020

Abstract
In this paper, the authors present an analysis of the collapse mode of tubes with circular cross-section under axial loads. Considering that requirements related to pollution are becoming more stringent, modern transportation systems require lightweight materials. These materials should have a high degree of protection. To reduce the CO2 emissions value, a vehicle is powered by an engine with a small displacement. Furthermore, to achieve good performances in terms of acceleration and maximum speed, the total mass of the vehicle should be decreased. In case of a collision, this energy is consumed, mainly, by controlled deformation of the sacrificial structures. During an impact, the dimensions of the cockpit must not change. The same time is necessary to obtain a minimal acceleration to ensure the health of the passengers. This requirement is not compatible with a rigid structure and leads to a high acceleration level. Sacrificial structures are defined by tubes with closed profiles. Studies related to thin-walled structures with the circular cross-section under axial loads have a strong background in the work of Guillow and Andrews. The paper proposes to add complemental information these charts for another type of material, and the result obtained are correlated with the limits from the other studies existing. The research is focused on the structures with the height correlated to the structures used in the automotive industry. The analysis of global buckling for the tall structures is completed by a theoretical evaluation using Euler’s equation.
Deriving patterns for the vibration-based damage detection in side frames of bogies
Authors: Barbinta C I , Gillich G R , Nedelcu D , Manescu T 
Published: December 2020

Abstract
Detecting damage in the incipient state is of crucial importance in monitoring the health of engineering structures. Approaching damage detection as an inverse problem is a common method when vibration-based techniques are used. It implies a precise a priori estimation of the modal parameters. We present in this paper a model to predict the frequency changes due to cracks in the side frames of bogies used to detect the welding defects in T-joints. To this aim, we model the structure and perform simulations using the SolidWorks software. The frequencies for the first thirteen modes are derived for the intact structure and the structure with different damage lengths and positions. By these tests, we first desire to find the optimal fixing of the side frame to reduce the number of vibration modes that are not of interest to the damage detection process. After finding the ideal fixing system, we derive patterns, for different defects, in the form of relative frequency shifts. Finally, we conclude about the damages that can be identified using the derived patterns, the conclusions being traced based on the measurability of the frequency changes.
Experimental stand for studying the stretch behaviour of woven plastic nets used in the food industry
Authors: Besnea D , Dinu E , Rizescu C , Moraru E , Rizescu D , Baran N , Pascu T , Panait I C 
Published: December 2020

Abstract
Mesh bags are the most modern way of packing, storing and transport used for packing vegetables and a variety of fruits. Mesh bags provide freshness, mechanical ventilation and offers a clear image of the content. Determination of elongation is one of the tests by which the nets used in the food industry must be done before their distribution. The mesh bags are made from recyclable materials, available in different colours and can be inserted into foil strips that provide ample space for images and product information. The products being analysed are polyethylene woven nets for packing vegetables (potatoes, onions, peppers, cabbage, carrots, cucumbers, etc.), fruits (apples, pears, oranges, lemons, nuts, etc.) in a diversified dimensional and coloristic form representing the cheapest and most accessible method of packaging. The authors had concerns in the field developing a series of stands with applications in the food industry.
Determinations regarding the influence on movement and comfort of different elastic suspension structures in N2 type vehicles
Authors: Mitroi M F , Chiru A 
Published: December 2020

Abstract
Modern technologies implemented in the automotive field bring a considerable increase of performance, but also safety at the same time. Moving the vehicle under such conditions also requires a high level of comfort, regardless of the type of road traveled.
The dynamics and behavior of the vehicle are conditioned by its constructive and functional characteristics. The research carried out highlights some aspects regarding the importance of elastomeric elements in the structures destined for shock and vibration damping.
Thus, different solutions adopted are analyzed, for the car's damping system, to reduce the specific disturbance factors of the road. For a vehicle of average load capacity, respectively 5 tonnes, used in determinations, checks are made on the various elastic systems with role in reducing shocks and vibrations. It is also intended that for the solutions adopted, the frequencies and amplitudes of the vibrations will occur at low values. By modeling the systems in AMESim, the aim is to identify the performance of the solutions adopted, as well as the level of comfort obtained.
Researches, studies and development prospects of the quality of metallic parts made on CNC
Authors: Puşcaş (Popescu) N , Tempea I 
Published: December 2020

Abstract
The quality of products is an important economic indicator. The paper presents studies, researches and development of prospects execution of bent metal parts on CNC machines. Through these studies we tried to find answers regarding the quality of products, problems that many companies face. Laborious studies and research proposed for the paper, on determining the drawings of metal parts (the flat plane). The quality and precision of the products, may influenced by the other variables: the vibrations of machines, tool usage, tolerance between the surface of the bending tools, variation of the temperature during the processes of punching and bending, their usage and the roughness of the metal sheet. The calculations of the drawing pieces must include the bending coefficients Kî. The bending coefficient obtanaited for de steel parts (OL 37) with a thickness of 1 mm, was the subject of the present paper. This coefficient Kî depends on: the type of the material, the chemical composition, the degree of complexity and the number of bends, the movement between the piece and punching or bending tools, vibrations of the machines and other variables. The bending coefficient was obtained by experimental tests and measurements.
A novel approach for assessing the instantaneous flow rate of an external gear pump using 3d printing and computer vision
Authors: Sarbu Valerian , Avram Mihai 
Published: December 2020

Abstract
The flow rate ripple inherent in gear pumps is already well researched with varying degrees of accuracy. The usual approach for determining the instantaneous flow rate includes mathematical models, computational fluid dynamics (CFD) and the practical approach, measuring the flow rate on an existing system using sensors. This paper presents an original method for determining the flow rate using new technologies, specifically 3d printing, edge computing and image processing. The target is a 3d printed scale model of the gears and casing attached to a stepper motor; a raspberry pi zero acts as a remote image capture device and position controller. The frames captured at key positions are wirelessly transferred to a computer running MATLAB for processing and extracting the flow data using special algorithms. Results were very good and reasonably accurate.
A new predictive model to estimate the frequencies for beams with branched cracks
Authors: Tufisi C , Gillich G R , Barbinta C I , Nedelcu D , Hamat C O 
Published: December 2020

Abstract
Detecting damage by using vibration signals is popular because it permits evaluating the structural integrity without being necessary scanning of the whole structure. The effect of transverse cracks is presented in detail in the literature, but in reality, the cracks can shift the direction of propagation and even split, resulting in the so-called branched crack. The effect of this type of crack is less investigated due to its complexity. We herein propose a simple model to predict frequency changes that occur due to branched cracks. Initially, we present the effect of stiffness reduction along the damaged section on the structure’s natural frequency. Next, we show that the predicted frequency drop is smaller that happens in reality. This is caused by the sudden cross-section reduction in the slice on which the transverse crack branch is. The phenomenon is similar to the stress concentration for static loads. We propose for dynamic systems a factor that considers the energy stored at the delamination ends. Considering this factor and the stiffness reduction on the damaged segment, we obtain accurate frequency changes due to any type of crack that extends in the longitudinal direction. The model is implemented in Python and tested successfully against simulation with dedicated software.
Design and analysis of a new bicontact cam mechanism
Authors: Alaci S , Ciornei F-C , Buium F 
Published: December 2020

Abstract
Based on an observation from a previous work, the authors use the degree of passive freedom of a mechanism with roller follower to propose a new type of mechanism. In the new mechanism, the roller is replaced by a jointed element that forms two contacts with the cam. The obtaining of the cam profile is the main disadvantage of the cam mechanisms but in the present work, by using a cam formed by two connected discs, it is aimed to be avoided. The method is illustrated by designing the mechanism in CAD software followed by the simulation of its movement. To optimize the movement of the final element, the equivalent mechanism with lower pairs is used which has the advantage that the lengths of the elements are constant. The kinematics of the final element is particularly sensitive to the variation of the dimensions of the mechanism, fact illustrated by an example.
Forces transmission in the case of SSR structural group
Authors: Duca C D , Buium F 
Published: December 2020

Abstract
This paper contains the SSR spatial group analysis, following to determinate the forces transmission index. It comes to conclusion, this index is a two variable function, defined by discrete values and graphically represented by a surface. Knowing this function it has been studied a linkage containing the SSR group – the spatial four bar linkage of orthogonal type. To avoid very high values of reactions, the forces transmission index must be inferior limited. Verifying of this limitation is done by the above mentioned surfaces level curves. This method is performed by authors, and it had been used previously for planar linkages only.
Geometric synthesis of the folding bridge mechanism
Authors: Moise V , Dugaesescu I , Ungureanu L M , Rotaru A 
Published: December 2020

Abstract
In London there is a folding bridge composed of eight platforms articulated between them. One platform is fixed to base (a platform from one end). The platforms have the shape of isosceles trapezoid. When the bridge is folded the large bases of the trapezoids form an octagon. The driving mechanism of the bridge is composed by motor dyads (active RRTaR groups) and RRR dyads. For the eight platform bridge the maximum piston stroke is less than the platform height (trapeze height). In this case, the connections between the hydraulic cylinders and the other elements are usually made, i.e. at the ends of the cylinder. If we want to make a folding bridge with fewer moving platforms, there are situations when the piston stroke is greater than the height of the trapeze. In this case must be performed the geometrical synthesis of the mechanism such that the folded bridge forms desired geometric figures (square, pentagon etc.).
Tower structure optimization through finite element analyses
Authors: Vlădulescu F , Constantinescu D M 
Published: December 2020

AbstractIn this study the objective is to obtain an optimal configuration for an antenna lattice tower which has an imposed height of 30 m. For this purpose, a variable geometric model which considers specific working parameters is created, and a 3D finite element (FE) model is generated by using beam and shell elements for an optimization study. The 3D FE analysis is updated automatically for each variant of the geometric model. The response surface methodology (RSM) is used together with the central composite design (CCD) approach as to optimize the response of the lattice tower. The model of the tower is subject to static and dynamic loadings, including earthquake analysis. A response spectrum analysis based on Rosenblueth's Double Sum Combination (ROSE) is performed because the natural frequencies resulting from the modal analysis have close values. The optimization solution algorithm used for the tower optimization is the nonlinear programming by quadratic Lagrangean (NLPQL), which is based on the gradient algorithm for models with only one objective function and several optimization restrictions. Out of three final candidate design solutions the one which gives the minimum mass is proposed.
Influence of warning lights for intervention vehicles on aerodynamic performance
Authors: Iozsa D , Ilea L , Fratila G 
Published: December 2020

Abstract
In today’s world, the freedom to travel is a daily necessity and part of human rights. This premise is directly linked to transport sector causative of air pollution. While the focus is on heavy transport and passenger vehicles, another important segment is represented by special utility vehicles such as the ones for intervention purposes (police, ambulance, etc.). The mandatory presence of warning lights bars has a big impact in aerodynamic performance and hence, in their emissions. The paper studies the influence of a generic lights bar on sedan, hatchback and SUV body types, in three main roof mounting positions – front, median, rear. Through CFD methods it is found that the most unfavourable case is the front mounted lights bar with 6g up to 12g CO2/km (WLTP conditions). The influence of median and rear mounting position is smaller, but still adds 3g to 7g CO2/km. Using streamlines, pressure and shear forces, future work will focus on optimizing the lights bar shape and size, for a reduced SCx impact in overall performance. This topic is considered very important since main cities (including Bucharest) started taxing or banning high pollution vehicles.
Influence of the flywheel profile on the energy storage capacity of the kers system
Authors: Milica L , Andrei G 
Published: December 2020

Abstract
When speaking about other energy storage devices, flywheels can be viable alternatives due to the low degradation process during the entire operating life, and its numerous energy discharge rates. In this paper, the problem of the flywheel shape, present in the KERS system, is approached analytically. The analysis was performed on three series of rotors and the results were validated using a CAD program. The linear relationship between the mass of the flywheel mass and its rotation axis was emphasized by Pappus-Guldin theorem. Based on the results it was shown that the value of kinetic energy is higher when the mass of the flywheel is concentrated closer to the axis of rotation.
The finite element analysis of pelvic assembly resulted from a pedestrian’s traffic accident. The dynamic analysis
Authors: Pascal I , Ciobotar C C , Gaidur M , Rakosi E , Manolache Gh , Talif S 
Published: December 2020

Abstract
The purpose of this study is to make a series of finite element analyses of the pelvic bone assembly of a pedestrian involved in a car crash. The analyses are of a dynamic type. In this way we took into consideration a normal pelvic bone assembly and an osteoporotic pelvic bone assembly. The conditions for analyses were chosen as to reflect the reality of the situation. With the help of this study the authors want to create a date base which aims to improve the time needed for achieving an accidentology technical expertise.