Development of the scheme and method for measuring the characteristics of the friction areas in the car wheel contact

The aim of the research is to develop and implement a scheme and method for measuring the characteristics of static and sliding friction areas in the contact patch of an elastic wheel with a solid support when they appear, exist and disappear. The characteristics are understood as: the relative location of static and sliding friction in relation to the vector of the translational speed of the wheel axis; their size and location in the contact patch when they appear, spread and disappear; the values of the moments on the wheel, corresponding to the appearance, spread and disappearance of static and sliding friction. A scheme and a method for measuring these characteristics have been developed and implemented. The measurements are indirect. It has been experimentally established that, in the general case, the geometric center of static friction in the contact patch moves towards the moment acting in the plane of the wheel rotation relative to the rotation axis by an amount proportional to the moment. The maximum value of this displacement according to the moment that is maximum in terms of sliding conditions, and is one third of the contact patch length for all types and conditions of a solid support. The research results are valid for elastic wheels with a radial stiffness not exceeding 12000000 N/m, the main plane of which is perpendicular to the reference plane. The research results can find application in design modeling of stability and controllability of vehicles.

Investigation of Low-Frequency Phenomena within Flow Pattern in Standard Mixing Vessel Induced by Pitched Blade Impeller

An experimental study on the flow pattern dynamics in a standard mixing vessel with radial baffles filled with water and induced by a pitched blade impeller pumping downward is presented. Investigation is mainly focused on detection and analysis of quasi-periodical or periodical low-frequency phenomenon connected with time- and length-scales considerably exceeding the Blade Passage Frequency (hereinafter BPF) and common turbulent eddies. This phenomenon, which is expressed as large-scale mean-flow variations, is generally known as flow Macro-Instability (hereinafter MI). It could break-down just below the liquid surface, or it crashes to the liquid surface and causes its Macro-Swelling (hereinafter MS). Our investigation was based on classical two-dimensional (2D) Particle Image Velocimetry (hereinafter PIV) measurement within 3 selected vertical planes in the vessel and subsequent analysis of the velocity field. The dominant frequencies evaluated in the selected points and overall analysis of the quasi-periodical macro-flow pattern behavior is to be shown. Identification of the quasi-periodical substructures appeared within the flow pattern was performed using the Oscillation Pattern Decomposition (hereinafter OPD) method. Observation of the macro-flow patterns confirmed presence of the macro-flow structures detected within flow pattern at the identical mixing pilot plant setup by previous investigations of the MIs phenomenon, i.e., the primary circulation loop and strong impeller discharge jet located in the lower vessel segment and the strong ascending wall current at the baffle, which break-down below the surface very often. A further important contribution of the presented work is the investigation of both flow pattern within the baffles vicinity and in the middle of the sector far from the baffle, showing a significant difference. Low-frequency periodical (or quasi-periodical) behavior of the investigated macro-structures was qualitatively confirmed by the presented results and it was quantified using the velocity dominant frequencies evaluation, as noted below. This frequency analysis brings insight into the supposed and detected interconnections between dynamics of the adjacent flow structures. Detected different flow patterns within the main plane near the baffles and in the inclined plane reveal a strong influence of the baffle presence to the local vertical flow, especially within the upper part of the vessel. Quite a different flow pattern appears tangentially in front of and behind the baffle, where a wake is revealed, indicating significant influence of the baffle on the local tangential flow. The new findings represent a contribution to better understanding the physical phenomena behind the standard mixing process.

А. ШЕНБЕРГ – В. КАНДИНСЬКИЙ : АНТРОПОСОФСЬКИЙ КОНТЕКСТ ТА ЛІНІЇ ПЕРЕТИНУ ТВОРЧИХ ПОШУКІВ

Стаття присвячена дослідженню впливу засадничих положень антропософії Р.Штайнера на художньо-естетичні принципи А. Шенберга та В. Кандинського.Виявлено, що основоположні засади вчення стали імпульсом для формування своєрідних новаторських методів творчості митців. Вплив антропософії передусім виявився у сприйнятті ідеї цілісності духовно-матеріального світу, в якому роль посередника відіграє мистецтво. Усвідомлення музики як провідної духовної субстанції, а також синестезії як митецької проекції Божественного світу, стало основною площиною формування творчої парадигми. Зокрема вказано, що вибір музично-виразових засобів А. Шенберга і В. Кандинського підпорядковувався інтуїтивному слідуванню Божественній ідеї.Ключові слова: антропософія Р. Штайнера, А. Шенберг, В. Кандинський, синестезія, абстракціонізм, синтез мистецтв. The article is devoted to the study of the influence of the main provisions of R. Steiner's anthroposophy on the artistic and aesthetic principles of A. Schoenberg and V. Kandinsky. It is revealed that the doctrine became an impulse for the formation of innovative methods of their creativity. The influence of anthroposophy was primarily in the perception of the idea of the integrity of the spiritual and material world, the role of the mediator is art. Awareness of music as a spiritual substance, as well as synesthesia as an artistic projection of the Divine world, became the main plane of formation of creative methods of artists. In particular, it is stated that the choice of the musical and expressive means of A. Schoenberg and V. Kandinsky obeyed the Divine idea and followed the intuition of the inner world of the artist.Key words: anthroposophy, R. Steiner, A. Schoenberg, V. Kandinsky, synesthesia, abstract art, synthesis of arts.

A Novel DR/NIR T-Shaped AIEgen: Synthesis and X-Ray Crystal Structure Study

We developed a new benzodifuran derivative as the condensation product between 2,6-diamino-4-(4-nitrophenyl)benzo[1,2-b:4,5-b’]difuran-3,7-dicarboxylate and 3-hydroxy-2-naphthaldehyde. The intramolecular hydrogen-bond interactions in the terminal half-salen moieties produce a sterically encumbered highly conjugated main plane and a D-A-D (donor-acceptor-donor) T-shaped structure. The novel AIEgen (aggregation-induced enhanced emission generator) fulfils the requirement of RIR (restriction of intramolecular rotation) molecules. DR/NIR (deep red/near infrared) emission was recorded in solution and in the solid state, with a noteworthy photoluminescence quantum yield recorded on the neat crystals which undergo some mechanochromism. The crystal structure study of the probe from data collected at a synchrotron X-ray source shows a main aromatic plane π-stacked in a columnar arrangement.

Power Spectrum in the Conductive Terrestrial Ionosphere

Stochastic differential equation of the phase fluctuations is derived for the collision conductive magnetized plasma in the polar ionosphere applying the complex geometrical optics approximation. Calculating second order statistical moments it was shown that the contribution of the longitudinal conductivity substantially exceeds both Pedersen and Hall’s conductivities. Experimentally observing the broadening of the spatial power spectrum of scattered electromagnetic waves which equivalent to the brightness is analyzed for the elongated ionospheric irregularities. It was shown that the broadening of the spectrum and shift of its maximum in the plane of the location of an external magnetic field (main plane) less than in perpendicular plane for plasmonic structures having linear scale tenth of kilometer; and substantially depends on the penetration angle of an incident wave in the conductive collision turbulent magnetized ionospheric plasma. The angle-of-arrival (AOA) in the main plane has the asymmetric Gaussian form while in the perpendicular plane increases at small anisotropy factors and then tends to the saturation for the power-low spectrum characterizing electron density fluctuations. Longitudinal conductivity fluctuations increase the AOAs of scattered radiation than in magnetized plasma with permittivity fluctuations. Broadening of the temporal spectrum containing the drift velocity of elongated ionospheric irregularities in the polar ionosphere allows to solve the reverse problem restoring experimentally measured velocity of the plasma streams and characteristic linear scales of anisotropic irregularities in the terrestrial ionosphere.

A Novel Calibration Board and Experiments for 3D LiDAR and Camera Calibration

Aiming at the problems of feature point calibration method of 3D light detection and ranging (LiDAR) and camera calibration that are calibration boards in various forms, incomplete information extraction methods and large calibration errors, a novel calibration board with local gradient depth information and main plane square corner information (BWDC) was designed. In addition, the "three-step fitting interpolation method" was proposed to select feature points and obtain the corresponding coordinates of feature points in the LiDAR coordinate system and camera pixel coordinate system based on BWDC. Finally, calibration experiments were carried out, and the calibration results were verified by methods such as incremental verification and reprojection error comparison. The calibration results show that using BWDC and the "three-step fitting interpolation method" can solve quite accurate coordinate transformation matrix and intrinsic and external parameters of sensors, which dynamically change within 0.2% in the repeatable experiments. The difference between the experimental value and the actual value in the incremental verification experiment is about 0.5%. The average reprojection error is 1.8312 pixels, and the value changes at different distances do not exceed 0.1 pixels, which also show that the calibration method is accurate and stable.

Modeling and Calibration of the Orthogonality Deviation between the "X" and "Y" Axes of Coordinate Measuring Machines

The increase of the quality in a productive process allows reduction of costs besides adding value to the product. When manufacturing a product within the tolerances specified in the design it is possible to obtain a correct operation of this product, ensuring the minimum time of use and with a lower risk of early failure. In this sense, machines and equipments involved in the manufacturing and inspection processes must also maintain an acceptable quality of operation by knowing the errors present in the machine structure through the calibration, such as errors due to lack of orthogonality between the axes, caused by inaccurate assemblies. The calibration errors in these machines allow elaborate error compensation plans and thus improve the rate of flawless products in production. The objective of this paper was to identify the influence of errors due to a lack of orthogonality in a bridge type coordinate measuring machine (CMM) through calibration and mathematical modeling of errors. Error calibration is performed with a linear displacement transducer, a granite square and a set support brackets for the granite square. By means of the calibration data and the mathematical modeling of the orthogonality deviation an influence of the measured deviation on the "X" and "Y" directions of the CMM is obtained. The error due to the lack of orthogonality between the "X" and "Y" axes of the CMM was approximately 8.9558 negative arcoseg; in this way, it is evidenced that the angle formed between these axes is 89.9975°. Through this study it can be concluded that orthogonality deviation in the main plane of the machine produces negative components for the axes "X" and "Y", with higher influence on the points collected as it away from machine scales, making greater the error intensity on the results of measurements made at positions farthest from the "X" and "Y" scales.

TWO METHODS FOR REMOTE ESTIMATION OF COMPLETE URBAN SURFACE TEMPERATURE

Complete urban surface temperature (<i>T</i>_C) is a key parameter for evaluating the energy exchange between the urban surface and atmosphere. At the present stage, the estimation of <i>T</i>_C still needs detailed 3D structure information of the urban surface, however, it is often difficult to obtain the geometric structure and composition of the corresponding temperature of urban surface, so that there is still lack of concise and efficient method for estimating the <i>T</i>_C by remote sensing. Based on the four typical urban surface scale models, combined with the Envi-met model, thermal radiant directionality forward modeling and kernel model, we analyzed a complete day and night cycle hourly component temperature and radiation temperature in each direction of two seasons of summer and winter, and calculated hemispherical integral temperature and <i>T</i>_C. The conclusion is obtained by examining the relationship of directional radiation temperature, hemispherical integral temperature and <i>T</i>_C: (1) There is an optimal angle of radiation temperature approaching the <i>T</i>_C in a single observation direction when viewing zenith angle is 45&amp;ndash;60°, the viewing azimuth near the vertical surface of the sun main plane, the average absolute difference is about 1.1&amp;thinsp;K in the daytime. (2) There are several (3&amp;ndash;5 times) directional temperatures of different view angle, under the situation of using the thermal radiation directionality kernel model can more accurately calculate the hemispherical integral temperature close to <i>T</i>_C, the mean absolute error is about 1.0&amp;thinsp;K in the daytime. This study proposed simple and effective strategies for estimating <i>T</i>_C by remote sensing, which are expected to improve the quantitative level of remote sensing of urban thermal environment.

Computational Analysis of Benzing Airfoils for Optimization in a Wing Configuration for a Formula SAE Car

Wing selection plays a crucial role for race cars as it generates the most downforce. This is essential to maintain traction which leads to faster lap timings, and maintain efficiency in the performance of the race car. In this paper, the numerical simulation of a Formula SAE (FSAE) Car is performed. The FSAE car is restricted by regulations in terms of the geometry of the front and rear wing configuration. Hence, it becomes necessary to optimize the selection of airfoils in order to get the best out of the wing configuration. It is also essential to observe the tradeoff between the downforce generated and the drag produced in a racecar for optimal performance. This serves as the primary motivation of this research paper. The focus is on Benzing airfoils, which show considerably better performance in terms of downforce production in a race car than conventional airfoils. The wing configuration utilized in this research paper consists of a single mainplane and two flaps.. The freestream velocity of the flow is in the range of 0–60mph (0–26m/s). The 122 series of Benzing airfoils is utilized for the mainplane and the 153 series of Benzing airfoils is utilized for the flaps for manufacturing reasons. Nine different combinations of Benzing airfoils were utilized wherein it was noticed that an appropriate selection of the airfoils for the mainplane and flaps with a fixed angle of attack difference, leads to a 12–15% increase in downforce amongst the Benzing airfoils itself. Similarly, it was also observed that an optimal configuration would lead to a 12–15% decrease in drag in comparison too poor performing airfoil. The Be 153-055 airfoil acts as an excellent flap within the limits of computational error. Data from an on-track test is used in order to verify the approach utilized in this paper in order to validate if the approach used in this paper would be feasible. It is observed that the Benzing airfoil does improve the average cornering speed of the car by around 10% in comparison to the previous configuration of S1223 airfoil as the main plane and the goe 477 airfoil as the flap.