Investigation of the Efficiency of Manufacturing Polymer Molds by FDM-Printing

The results of experimental studies of the efficiency of manufacturing polymer foundry models by the FDM method are presented. Rational consumables for 3D-printing are revealed. The optimal values of the shrinkage value of the 3D-model during printing and the parameters of the 3D-printer operation mode are revealed. It has been established that polymer casting molds are rationally manufactured by FDM printing, using ABS-plastic as a consumable, while making a correction to linear dimensions at the stage of creating a 3D-model to eliminate plastic shrinkage.

APPLICATION OF nonPLANAR MICROSTRIP MICROWAVE STRUCTURES FOR gauging the DIELECTRIC PARAMETERS OF LIQUIDS AND SOLID MATERIALS

В данной статье отражаются основные результаты компьютерного моделирования, практической реализации и применения непланарной микрополосковой периодической СВЧ структуры в качестве преобразовательного элемента в задачах контроля диэлектрических параметров материалов и веществ. Основными достоинствами подобной реализации датчика являются большая чувствительность и относительно небольшие линейные размеры по сравнению с аналогичными, реализованными на основе планарных СВЧ структур. Помимо этого, благодаря непланарной форме микрополосковой линии расширяется диапазон областей применения СВЧ датчиков. This article reflects the main results of computer modeling, practical implementation and application of a nonplanar microstrip periodic microwave structure as transducer in the problems of gauging the dielectric parameters of materials and substances. The main advantages of such a sensor implementation are high sensitivity and relatively small linear dimensions in comparison with similar ones based on planar microwave structures. In addition, due to the nonplanar shape of the microstrip line, the range of applications for microwave sensors is expanded.

Development of a method for improving the accuracy of measurement of linear measures of 3D models via scanning

The object of research is to refine the linear sizes of the obtained 3D models via scanning, and reducing the numbers of errors when obtaining the model. For now, there is no accuracy method for transferring the actual sizes of an object to a 3D model. One of the most problematic places in the existing methods of transferring sizes from the object to the model is the error in the placement of dimensional markers due to inaccuracy, or poor quality of the received surface via scanning. A model of the instrument complex is used to implement an improved method of 3D scanning, based on the photogrammetric method. The advanced technology of construction and measurement of 3D models on the basis of photos on the principle of stereo pairs in combination with image projection is based on a combination of existing scanning methods. As well as the introduction of new functionalities, such as maintaining the actual sizes of an object, its textures, color and light characteristics, as well as improving the accuracy of linear sizes. As a result of the use of a standard, reference projections, and a new method of comparing photographs to build a 3D model, a 60 % increase in the accuracy of linear dimensions was achieved. This is due to the fact that the proposed new combined method incorporates all the existing most important aspects of scanning. And also has a number of features, such as the definition of boundary surfaces, automatic sizing, detection, and processing of glass and mirror surfaces. Due to this, this method eliminates the main disadvantages of the usual photogrammetric method – inaccuracies in the surface quality of the models, and inaccuracies in the transfer of linear dimensions. It is estimated that the combined method will allow to transfer the real size of simple objects in 3D with an accuracy of 99.97 % of the actual size of the object. It will also improve the quality of complex surfaces (boundary, glass, mirror) by at least 40–60 %, compared to other existing methods.

FIRST RESULTS OF PROCESSING DIGITIZED V-PLATES TAKEN WITH THE TAUTENBURG 2m SCHMIDT TELESCOPE

The process of treatment of about 500 digitized plates has started in MAO NAS of Ukraine. Plates were taken with the Tautenburg 2m Schmidt telescope in 1963-1989. Linear dimensions of plates are 24x24 cm with a working field of 3.3x3.3 degrees and a scale of 51.4 "/ mm. Astronegatives were digitized on the Tautenburg Plate Scanner in five strips with linear dimensions of 5 400x23 800 px. The software developed in MAO NAS of Ukraine for the image processing of these scans takes into account the horizontal overlap and the vertical offset of strips. The photometric range of fixed objects is 12 magnitudes, around V = 7 m - 19 m , due to the separation of objects into faint and bright parts by their images’ diameters. Positions of stars and other fixed objects are obtained in the GAIA DR2 reference system. Magnitudes are defined in the V-band of the Johnson color system. The resulted positional accuracy defined from 180 plates’ processing is σ RA,DEC = 0.10"for both coordinates, photometric error on the whole range of magnitudes is σ V = 0.14 m . The convergence of resulted magnitudes with ones from photoelectric standards’ data is 0.19 m . In parallel with image processing and plate data reduction, the search for minor planets’ images was carried out. Nine positions and magnitudes of 4 asteroids registered on the plates obtained in 1963-1965 were defined and used for further analysis.

Discriminative Power of Geometric Parameters of Different Cultivars of Sour Cherry Pits Determined Using Machine Learning

The aim of this study was to develop models based on linear dimensions or shape factors, and the sets of combined linear dimensions and shape factors for discrimination of sour cherry pits of different cultivars (‘Debreceni botermo’, ‘Łutówka’, ‘Nefris’, ‘Kelleris’). The geometric parameters were calculated using image processing. The pits of different sour cherry cultivars statistically significantly differed in terms of selected dimensions and shape factors. The discriminative models built based on linear dimensions produced average accuracies of up to 95% for distinguishing the pit cultivars in the case of ‘Nefris’ vs. ‘Kelleris’ and 72% for all four cultivars. The average accuracies for the discriminative models built based on shape factors were up to 95% for the ‘Nefris’ and ‘Kelleris’ pits and 73% for four cultivars. The models combining the linear dimensions and shape factors produced accuracies reaching 96% for the ‘Nefris’ vs. ‘Kelleris’ pits and 75% for all cultivars. The geometric parameters with high discriminative power may be used for distinguishing different cultivars of sour cherry pits. It can be of great importance for practical applications. It may allow avoiding the adulteration and mixing of different cultivars.

Generation of double-frequency radiation in monotron with three-gap cavity

Purpose of this work is to study modes and conditions that make it possible to excite the highest type of microwave oscillations, the frequency of which is a multiple of the frequency of the main type, in a monotron with a three-band resonator. Method of the investigation is a numerical 3D modeling, used to calculate the dimensions and electrodynamic parameters of the resonator (characteristic impedance, coupling coefficient, relative electronic conductivity); operation modes of the monotron are considered, which are characterized by excitation of oscillations in the highest type oscillations. Result. In the resonator under consideration, it is possible to achieve a multiple (equal to three) ratio between the frequency of the 25th highest type of oscillations and the frequency of the π/2-type. It was shown that in such resonator simultaneous excitation of electromagnetic field on those frequencies can be made. The maximum of an output power achieved at 100.22 GHz is 15.4 W with an accelerating voltage of 7825 V and an electronic beam microperveance 0.36 µA/V3/2 . The maximal efficiency on a third harmonic is 0.83% while the total efficiency (generating electromagnetic waves of the first and the third harmonics) is up to 17%. Conclusion. It was set that the described method of generation of terahertz range radiation is promising for further investigation, as it solves problem that orthodox microwave devices meet in the millimeter wavelength range, such as small linear dimensions of the components and critical current density of the electronic beam.

3D-modeling of an experimenal wound channel caused by a piercing-cutting object with bilateral blade grinding

The research deals with the possibility to use up-to-date methods of 3D-modeling for diagnostics of piercing-cutting objects causing injuries with bilateral blade grinding. A virtual element of the wound channel is shown to be printed on 3D-printer and given to investigating bodies in order to increase the effective and objective search of a traumatic instrument. Aim of the work. To apply the method of photogrammetry with further 3D-modeling of the wound channel formed by a piercing-cutting object with bilateral blade grinding for further examination of its morphological peculiarities and receiving its linear size with high accuracy in the space of graphics editor «3DsMax». Materials and methods. Fifteen experimental wound channels were made by means of alginate impression mass with rubber-like effect «Hydrogum 5» (firm «Zhermack», Italy), which becomes hard rapidly, remains elastic after polymerization, allows impresses to be obtained with an extremely smooth surface, most accurately preserves and reproduces characteristics of an immersed blade of the knife examined. To make experimental injury a piercing-cutting object was used – a knife with bilateral grinding of the blade 6,16 cm long, 2,6 cm wide in the base of the blade, and the blade in its middle part 0,3 cm thick. These sizes of the piercing-cutting instrument were obtained by means of sliding calipers with the error ±0,03-0,15 cm. The wound channel obtained was divided into fragments with a pitch about 3,5 cm. Every fragment of the wound channel was contrasted with a dye using 1 % brilliant green alcohol solution. All the fragments of the wound channel were opened parallel to its length and were placed on a rotary table located in a light cube to provide adequate illumination and photos were taken. The digital camera SONY RX 10 II was used for shooting. The object of shooting was labeled with a number, a fragment of a plotting scale 1,0 cm long was placed on it to calibrate the scale and control the sizes of the object examined in computer programs. The photos obtained in JPEG format were loaded into the computer program «Agisoft Photoscan», and 3D-textured models of a wound channel fragment were created in it. The model obtained and the texture was exported in «OBJ» format. The next stage of the work was to transfer 3D-models obtained into the graphic space of «3DsMax» program, where the scale of the model was calibrated. After that the wound channel was reconstructed in the graphics editor by means of 3D models of the wound channel fragments. Results. To compare differences between classical and new methods of examination at first linear dimensions of injuries were measured by means of a ruler. The depth of the wound channel was obtained consisting of two fragments according to the method of measuring the wound channel depth in the dead body by means of joining of its separate parts due to immersion and passing the blade in the victim’s body (in the skin, subcutaneous tissue with muscles, in the wall of the cavity and inside of it, in the internal organ and other anatomical structures). The width and length of the wound channel on various levels of immersion were registered in the similar way, which is an important diagnostic component during forensic expertise in case of piercing-cutting injuries. The next stage in our research was to examine and get linear dimensions of injuries by means of up-to-date technologies using 3D-models with the help of the graphics editor «3DsMax». In this case the computer program enabled to get the above results with a higher accuracy to 0.001 cm. Conclusions. The results obtained are indicative of high information value of the three dimensional methods to identify a traumatic piercing-cutting object by means of a spatial reconstruction of the wound channel fragments, which provides high accuracy in solving applied tasks in modern forensic practice and criminal law science. The method with the use of the graphics editor «3ds max» allows retrospective diagnostics of the wound channel fragments to be obtained followed by further comparison with an expected traumatic object.

BIOLOGICAL SEXUAL PROFILE BASED ON LINEAR DIMENSIONS OF HUMERI AND FEMURS OF ADULT BRAZILIAN HUMAN SKELETONS

This research aimed to assess the predictive ability and applicability for sexual diagnosis of algorithms developed from measurements of humeri and femurs from skeletons belonging to the CEAF Identified Skeletal Collection of the University of Pernambuco, Brazil. The sample was composed of 483 humeri and 452 femurs, obtained from 401 skeletons, 208 male and 193 female, with ages ranging from 15 to 109 years. The variables used were the transverse and vertical diameters of the humeral and femoral heads and the epicondylar width of these bones. The data collected were analyzed using R software (version 3.6.1, R Foundation for Statistical Computing). Only the univariate logistic regressions were considered predictive, making it possible to estimate sex based on any single variable in this study. The accuracy ranged from 93.8% to 97.5% for the humerus evaluation and from 92.9% to 95.6% for femurs, with the transverse diameter of the right humeral head being the most dimorphic measurement. Therefore, it is inferred that the sexual dimorphism present in the measurements of the humeri and femurs of our sample is high and enables the classification of sex reliably and assertively using the algorithms created.

RESULT OF ANALYSIS OF DEPENDENCE OF THE NUMBER OF FULFILLED AND RUDIMENTARY LOTUS KOMAROV SEEDS ON THE SIZE OF SEED BOXES

The seeds collected from individually selected plants were studied according to the main linear parameters of morphological elements, the degree of variability and the presence of percentages. The main regularities between the linear dimensions of the seed elements and the size of the seed capsule containing them are revealed.

Analysis of Filtration Process Influence on the Results of Thermal Imaging Control of the Subsurface Defect’s Geometry in Solving Control Problems of Collaborative Robotic Systems

The paper proposes and experimentally verifies an approach for estimating the thermal imaging error depending from the method of the subsurface defect’s linear dimensions filtering for forming the appropriate commands of the control program in a collaborative robotic system. The results are presented for the absolute error estimation depending on the filtration method with a confidence probability p=0,9972.