The formulation of a plate finite element with so called ‘physical’ shape functions is revisited. The derivation of the ‘physical’ shape functions is based on Hencky-Bollé theory of moderately thick plates. The considered finite element was assessed in the past, and the tests showed that the solution convergence was achieved in a wide range of thickness to in-plane dimensions ratios. In this paper a holistic correctness assessment is presented, which covers three criteria: the ellipticity, the consistency and the inf-sup conditions. Fulfilment of these criteria assures the existence of a unique solution, and a stable and optimal convergence to the correct solution. The algorithms of the numerical tests for each test case are presented and the tests are performed for the considered formulation. In result it is concluded that the finite element formulation passes every test and therefore is a good choice for modeling plate structural elements regardless of their thickness.

The behaviour of energy levels and optical spectra of a charged particle (electron or hole) confined within a potential well of ellipsoidal shape is investigated as a function of the shape-anisotropy parameter. If two energy levels of the same symmetry intersect in a perturbation-theory approximation, they move apart on direct diagonalization of the appropriate Hamiltonian. The intersection of the energy levels leads to a discontinuity of the corresponding dipole-moment matrix element. The discontinuity of matrix elements is not reflected in the behaviour of transition probabilities which are continuous functions of the shape-anisotropy parameter. The profiles of a spectral line emitted or absorbed by an ensemble of ellipsoidally shaped nanoparticles with a Gaussian distribution of size are calculated and discussed.

Similarity assessment between 3D models is an important problem in many fields including medicine, biology and industry. As there is no direct method to compare 3D geometries, different model representations (shape signatures) are developed to enable shape description, indexing and clustering. Even though some of those descriptors proved to achieve high classification precision, their application is often limited. In this work, a different approach to similarity assessment of 3D CAD models was presented. Instead of focusing on one specific shape signature, 45 easy-to-extract shape signatures were considered simultaneously. The vector of those features constituted an input for 3 machine learning algorithms: the random forest classifier, the support vector classifier and the fully connected neural network. The usefulness of the proposed approach was evaluated with a dataset consisting of over 1600 CAD models belonging to 9 separate classes. Different values of hyperparameters, as well as neural network configurations, were considered. Retrieval accuracy exceeding 99% was achieved on the test dataset.

This research presents comprehensive assessment of the precision castings quality made in the Replicast CS process. The evaluation was

made based on quality of the surface layer, shape errors and the accuracy of the linear dimensions. Studies were carried out on the modern

equipment, among other things a Zeiss Calypso measuring machine and profilometer were used. Obtained results allowed comparing lost

wax process models and Replicast CS process.

In the paper an analysis of the influence of two parameters on the die wear, i.e. the shape of the die and the backpull with the specified force values has been presented. The conical and curve-profile tools have been selected to determine an influence of the die geometry on its wear, and the backpull force has been tested with the use of conical dies. The research was conducted for the drawing of copper wire by sintered carbide die with a mesh diameter of 3 mm. A fixed draw value of 30% relative gap loss was assumed. The axisymmetric numerical model of the drawing process was built and modeled in the MARC/Mentat commercial program for nonlinear and contact issues. As a result of the tests, wear of the dies according to their shape was determined. In addition, for the conical die the drawing force and the force of the metal pressure on the die using different values of the force of the contraction were calculated, as well as wear of the conical die according to the value of the applied backpull force. It has been shown that in the case of the arc die, the distribution of pressure and stress is more uniform over the entire length of the contact zone compared to the conical die. The highest stress gradients occurred in the area of the transition of the crushing part into the drawing part of the die, which caused that the use of the conical die in this area was more than twice as large as the arc die. In addition, on the example of a conical die, it was shown to what extent the depth of its wear decreases with an increase of the test pull force in the range (0-400) of Newtons.

In this paper, we proposed a novel design of U-slotted SIW antenna. Our antenna design is aimed to cover upper K-band and lower Ka-band spectrums, specifically from 24 GHz to 32 GHz. It has a compact square size of 5.2 x 5.2 mm2. We use a rectangular truncated corner to optimize the square radiator. The optimized rectangular truncated corner size of 2 x 0.8 mm2 gives an impedance bandwidth of 7.87 GHz. SIW cavity is constructed by using multiple metallic via-holes which are drilled in a dielectric substrate establishing. Next optimization, applying the U-shaped slot and SIW structure yield a wider impedance bandwidth of 8.89 GHz, there is about 1.02 GHz of impedance bandwidth enhancement. In addition, the SIW structure gives a higher gain of 7.63 dB and decreases the sidelobe level of -12.1 dB. Implementation of the SIW structure significantly decreases the size of antenna while keeping the antenna parameter’s performances.

The article presents a constitutive model for Shape Memory Alloys (SMA) along with result of dynamic simulations of SMA model. The applications of devices incorporating SMA in civil engineering focus mostly on mitigation of the seismic hazard effects in new-build and historical buildings or improvement of fatigue resilience. The unique properties of SMA, such as shape memory effect and superelasticity give promising results for such applications. The presented model includes additional phenomenon of SMA – internal loops. The paper shows the method of formulation of physical relations of SMA based on special rheological structure, which includes modified Kepes’s model. This rheological element, introduced as dual-phase plasticity body, is given in the context of martensite phase transformation. One of the advantages of such an approach is a possibility of formulation of constitutive relationships as a set of explicit differential equations. The application of the model is demonstrated on example of dynamic simulations of three dimensional finite element subjected to dynamic excitation.

This paper presents the measurement of vibrational properties of sundatang soundboard. Sundatang is a plucked stringed traditional musical instrument that is popular among the Kadazandusun communities in Sabah, Malaysia. The vibrational properties of the soundboard are measured using CADA-X impact hammering system in a condition where the instrument is without any string. There are two types of sundatang used in this study; one made from acacia and the other from vitex wood. In this measurement, frequency response functions (FRFs) and modal parameters of the top plate and back plate of this instrument are obtained. It is found that in free edge, fundamental frequency of both plates of acacia sundatang is greater than the vitex sundatang in a range of 112 Hz to 230 Hz. However, in clamped edge (attached to its ribs), it was modified to a lower frequency and closer to each other in the range of 55 Hz to 59 Hz. Another finding is the detection of the excitation of similar mode shape at different resonance frequencies. This phenomenon is termed as Different State of Mode (DSM) which is observed may be because the number of testing points is not enough. Findings of this study provide important information to the study of quality development of this instrument

There is a considerable increase in the use of noise barriers in recent years. Noise barriers as a control noise solution can increase the insertion loss to protect receivers. This paper presents the results of an investigation about the acoustic efficiency of primitive root sequence diffuser (PRD) on an environmental single T-shape barrier design. A 2D boundary element method (BEM) is used to predict the insertion loss of the tested barriers. The results of rigid and with a different sequence diffuser coverage are also predicted for comparison. Employing PRD on the top surface of T-shape barrier has been found to improve the performance of barriers in comparison with the use of rigid and QRD coverage at the examined receiver locations. It has been found that decreasing the design frequency of PRD shifts the frequency effects towards lower frequencies, and therefore the overall A-weighted insertion loss is improved. It was also found that using wire mesh with reasonably efficient resistivity on the top surface of PRD improves the efficiency of the reactive barriers; however utilizing wire meshes with flow resistivity higher than the specific acoustic impedance of air on the PRD top of a diffuser barrier significantly reduces the performance of the barrier within the frequency bandwidth of the diffuser. The performance of a PRD covered T-shape barrier at 200 Hz was found to be higher than that of its equivalent QRD barriers in both the far field and in areas close to the ground. The amount of improvement compared made by PRD barrier compared with its equivalent rigid barrier at far field is about 2 to 3 dB, while this improvement relative to the barrier model "QR4" can reach up to 4-6 dB.

An optical tomograph in which a tested object is illuminated from five directions has been presented in the paper. The measurements of luminous intensity after changing into discrete signals (0 or 1) in the detectors equipped with 64 optical sensors were subjected to reconstruction by means of the matrix algorithm. Detailed description of the measuring sensor, as well as the principles of operation of the electronic system, has been given in the paper. Optical phenomena occurring at the phase boundary while transmitted through the sensor wall and phenomena inside the measuring space have also been taken into account. The method of the sensor calibration has been analysed and a way of technical solution of the problem under consideration has been discussed. The elaborated method has been tested using objects of the known shape and dimensions. It was found that reconstruction of the shapes of moving bubbles and determination of their main parameters is also possible with a reasonable accuracy.

In this paper, the influence of Mo addition on the structure and mechanical properties of the NiCoMnIn alloys have been studied. Series of polycrystalline NiCoMnIn alloys containing from 0 to 5 mas.% of Mo were produced by the arc melting technique. For the alloys containing Mo, two-phase microstructure was observed. Mo-rich precipitates were distributed randomly in the matrix. The relative volume fraction of the precipitates depends on the Mo content. The numbers of the Mo rich precipitates increases with the Mo contents. The structures of the phases were determined by the TEM. The mechanical properties of the alloys are strongly affected by Mo addition contents. Brittleness of the alloys increases with the Mo contents.

Usually porous metals are known as relatively excellent characteristic such as large surface area, light, lower heat capacity, high toughness and permeability for exhaust gas filter, hydrogen reformer catalyst support. The Ni alloys have high corrosion resistance, heat resistance and chemical stability for high temperature applications. In this study, the Ni-based porous metals have been developed with Hastelloy powder by gas atomization and water atomization in order to find the effects of powder shape on porous metal. Each Hastelloy powder is pressed on disk shape of 2 mm thickness with 12 tons using uniaxial press machine. The specimens are sintered at various temperatures in high vacuum condition. The pore properties were evaluated using Porometer and microstructures were observed with SEM.

Cardiovascular system diseases are the major causes of mortality in the world. The most important and widely used tool for assessing the heart state is echocardiography (also abbreviated as ECHO). ECHO images are used e.g. for location of any damage of heart tissues, in calculation of cardiac tissue displacement at any arbitrary point and to derive useful heart parameters like size and shape, cardiac output, ejection fraction, pumping capacity. In this paper, a robust algorithm for heart shape estimation (segmentation) in ECHO images is proposed. It is based on the recently introduced variant of the level set method called level set without edges. This variant takes advantage of the intensity value of area information instead of module of gradient which is typically used. Such approach guarantees stability and correctness of algorithm working on the border between object and background with small absolute value of image gradient. To reassure meaningful results, the image segmentation is proceeded with automatic Region of Interest (ROI) calculation. The main idea of ROI calculations is to receive a triangle-like part of the acquired ECHO image, using linear Hough transform, thresholding and simple mathematics. Additionally, in order to improve the images quality, an anisotropic diffusion filter, before ROI calculation, was used. The proposed method has been tested on real echocardiographic image sequences. Derived results confirm the effectiveness of the presented method.

This paper presents a piecewise line generalization algorithm (PG) based on shape characteristic analysis. An adaptive threshold algorithm is used to detect all corners, from which key points are selected. The line is divided into some segments by the key points and generalized piecewise with the Li-Openshaw algorithm. To analyze the performance, line features with different complexity are used. The experimental results compared with the DP algorithm and the Li-Openshaw algorithm show that the PG has better performance in keeping the shape characteristic with higher position accuracy.

The agglomeration of particles is a process that modifies the physical properties of a product originally manufactured as a powder. During milk powder agglomeration of fluidized bed, resulting agglomerates are sufficiently porous to improve the solubility of the final product but, at the same time, their rigidity decreases and agglomerates can be destroyed during packing. The porosity and rigidity properties depend on both the volume and shape characteristics of the agglomerates. This paper presents a three-dimensional reconstruction technique based on a laser displacement sensor (LDS) applied to characterize milk agglomerates. This technique allows three-dimensional scanning to estimate particle volume and extract shape parameters such as: sphericity, elongation and flatness ratio, shape factor and aspect ratio. This technique was implemented using a mechatronic device with two degrees of freedom. The device is composed of an angular positioning system to rotate the agglomerate and a linear positioning system to displace the LDS. Experimental result allows agglomerates classification according to shape parameters

Shape memory alloys are characterised by interesting properties, i.e. shape memory effect and pseudoelasticity, which enable their increasing application. Thermomechanical aspects of martensitic and reverse transformations in TiNi shape memory alloy subjected to tension tests were investigated. The stress-strain characteristics obtained during the tests were completed by the temperature characteristics. The temperature changes were calculated on the basis of thermograms determined by an infrared camera. Taking advantages from the infrared technique, the temperature distributions on the specimen’s surface were found. Heterogeneous temperature distributions, related to the nucleation and development of the new martensite phase, were registered and analysed. A significant temperature increase, up to 30 K, was registered during the martensitic transformation. The similar effects of the heterogeneous temperature distribution were observed during unloading, while the reverse transformation, martensite into austenite took place, accompanied by significant temperature decrease.

The paper describes the influence of graphite shape, size and amount to electrical properties of different cast irons. Experiments of electrical resistivity measurements were conducted during solidification of four different melts in different time intervals from melt treatment by inoculation and nodularization. Metallographic analyses were made in order to determine the shape, size, distribution and amount of graphite and correlate results with electrical resistivity measurements. It was found out that nodular graphite is giving the lowest electrical resistivity and is decreased during solidification. Electrical resistivity of lamellar cast iron is increased during solidification since lamellas interrupt metal matrix severely There is no significant difference in resistivity of vermicular cast iron from nodular cast iron. Smaller size of graphite and lower amount of graphite and higher amount of metal matrix also decrease resistivity.

Cu-Al-based high temperature shape memory alloys are preferred commonly due to their cheap costs and shape memory properties. In recent years, studies have been conducted on developing and producing a new type of Cu-Al based shape memory alloy. In this study, the CuAl-Cr alloy system, which has never been produced before, is investigated. After production, the SEMEDX measurements were made in order to determine the phases in the Cu84–xAl12Crx+4 (x = 0, 4, 6) (weight %) alloy system; and precipitate phases together with martensite phases were detected in the alloys. The confirmations of these phases were made via x-ray measurements. The same phases were observed by XRD diffractogram of the alloys as well. The values of transformation temperature of alloys were determined with Differential Scanning Calorimetry (DSC) at 20°C/min heating rate. According to the DSC results, the transformation temperature of the alloys varies between 320°C and 350°C. This reveals that the alloys show high temperature shape memory characteristics.

At the current stage of diagnostics and therapy, it is necessary to perform a geometric evaluation of facial skull bone structures basing upon virtually reconstructed objects or replicated objects with reverse engineering. The objective hereof is an analysis of imaging precision for cranial bone structures basing upon spiral tomography and in relation to the reference model with the use of laser scanning. Evaluated was the precision of skull reconstruction in 3D printing, and it was compared with the real object, topography model and reference model. The performed investigations allowed identifying the CT imaging accuracy for cranial bone structures the development of and 3D models as well as replicating its shape in printed models. The execution of the project permits one to determine the uncertainty of components in the following procedures: CT imaging, development of numerical models and 3D printing of objects, which allows one to determine the complex uncertainty in medical applications.

The structural system of a multiple strip-shaped pillar-roof is common in underground mine exploitation, and research on its mechanics and micro/macroeconomics is meaningful for utilizing strip-shaped pillar resources. A general model of the structural system of a multiple strip-shaped pillar-roof was established, the deformation mechanism of the model was analysed by material mechanics, and the deflection curve equations of the model were obtained. Based on the stress strain constitutive relation of the strip pillar and cusp catastrophe theory, the nonlinear dynamic instability mechanism of the structural system of a multiple strip-shaped pillar-roof was analysed, and the expressions of the pillar width for maintaining the stability of different types of structural systems were derived. The benefits of different structural systems were calculated using micro/macroeconomic theory, the type of the structural system was determined, and different recovery schemes were obtained. Theoretical application research was applied to a large manganese mine, and the results demonstrate that no pillar recovery was needed in 2016, a 9-m wide artificial pillar could be built to replace a pillar in 2017, and the construction of 14-m wide artificial pillars can be conducted in 2018.