Differences In Geometrical Parameters Research Articles

The geometry uniformity parameters effect on the dynamic behaviour of trapezoidal beam

Understanding the delicate interplay between geometric design principles and dynamic responses is vital for numerous engineering applications because it allows optimization of structural integrity and performance for manufacturing and special use of this structures. In this study, a complete numerical analysis is undertaken to investigate how differences in geometric parameters impact the structural behaviour of a cantilever smart trapezoidal beam, giving useful insights for engineering applications. The beam consists of a host structure made of aluminum couple with two piezoelectric layers on its top and bottom surface. For such purpose, the study a 3D finite element model has been implemented in ANSY APDL and applied by Matlab we used the interfaces between the two software, considering that the beam changes its form in the axial direction following polynomial based function. The function takes two geometric parameters as an input which are the tapering ratios and the degree of non-uniformity. The beam is then subjected to a harmonic based excitation and the effect of changing tapering ratios and the degree of non-uniformity is analyzed., allowing analysis of the effects of altering tapering ratios and the degree of non-uniformity The results led to a conclusion that just by manipulating the mentioned parameters a considerable changing in the fundamental frequency and the amplitude has been noticed. Addition our numerical analysis shows that small changes to the tapering ratios and degree of non-uniformity have a considerable influence on the behavior of cantilever smart trapezoidal beams. These discoveries add to continuing research in smart materials, paving the road for creative engineering solutions.

Снижение потерь угля при работе карьерных мехлопат

A significant part of operations that are engaged in surface mining of coal are currently using hydraulic excavators, i.e. backhoes and less often face shovels, which reduces losses and improves productivity. However, a certain number of strip mines, especially those where mining activities are coming to a close, are still using mining rope shovels mostly domestically produced and of outdated models. Based on the method developed by the authors earlier and partially described in this article, the calculation of the layer height is made which will prevent additional losses of coal from the insufficient cutting depth. Formulas for calculating the layer height are proposed for five models of domestically produced rope shovels. The differences in geometric parameters of relative location of the elements that are used in the method described do not make it possible to establish a unified dependence of the worked-out layer height on the influencing factors. However, this method can be used to define the layer height for any model of the rope shovels, but this will require to know its operating parameters, i.e. the height of the shipper shaft, the distance from the excavator rotation axis to the tail piece of the boom, the minimum digging radius, etc.

Neural Network-Based Train Identification in Railway Switches and Crossings Using Accelerometer Data

This paper aims to analyse possibilities of train type identification in railway switches and crossings (S&C) based on accelerometer data by using contemporary machine learning methods such as neural networks. That is a unique approach since trains have been only identified in a straight track. Accelerometer sensors placed around the S&C structure were the source of input data for subsequent models. Data from four S&C at different locations were considered and various neural network architectures evaluated. The research indicated the feasibility to identify trains in S&C using neural networks from accelerometer data. Models trained at one location are generally transferable to another location despite differences in geometrical parameters, substructure, and direction of passing trains. Other challenges include small dataset and speed variation of the trains that must be considered for accurate identification. Results are obtained using statistical bootstrapping and are presented in a form of confusion matrices.

Investigation of conformational structures of gemcitabine and its 2′,2′-difluoro 2′-deoxy derivatives: A computational study

This study investigates the electronic structure of natural DNA nucleosides and their 2′-difoluoro analogues to assess the possible substitution effects of two hydrogen atoms with fluorine ones in the positions of sugar moiety. Gemcitabine representing an analogue with specific features was utilized in this study. To conduct proper calculations, DFT method at the B3LYP/6-31+G* level was accordingly used. In terms of conformational characteristics of gemcitabine and other analogues, full geometry optimizations, atomic charges, dipole moments, NBO, and HOMO & LUMO were duly made. PROSIT was also used to calculate the pseudorotational parameters of gemcitabine and the DNA analogues. The outcome proved that all the 2-difoluoro DNA nucleosides have slight differences in geometrical parameters with natural nucleosides.

Overlapping Phenotypes and Degree of Ventricular Dilatation Are Associated with Severity of Systolic Impairment and Late Gadolinium Enhancement in Non-Ischemic Cardiomyopathies.

BackgroundDilatation and other infrastructural rearrangements of the left ventricle are connected with poor prognosis. The aim of our study was to analyze the overlapping phenotypes and dilatation of the ventricle on impairment of systolic function and existence of late gadolinium enhancement (LGE).Material/MethodsConsecutive sample of cases with dilated left ventricle due to non-ischemic cardiomyopathy and healthy controls were included from our cardiac magnetic resonance imaging (CMR) database for a period of 3 years (n=1551 exams).ResultsThe study included 127 patients; 30 (23.6%) with dilated cardiomyopathy (DCM); 30 (23.6%) with left ventricular non-compaction (LVNC); 13 (10.2%) with hypertrophic cardiomyopathy (HCM), and 50 (39.4%) controls. Overlapping phenotypes were found in 48 (37.8%) of the studied cases. Odds for impairment of systolic function in connection with overlapping phenotypes were estimated at 7.8 (95%-CI: 3.4–17.6), (p<0.001). There were significant differences in geometric parameters for patients with overlapping phenotypes vs. controls, as follows: left ventricle end-diastolic dimension(LVEDD)=6.6±0.8 vs. 5.6±1.0 cm (p<0.001); left ventricular ejection fraction (LVEF)=39.3±14.0 vs. 52.1±16.1 (p<0.001); and existence of LGE 36 (75.0%) vs. 21 (26.6%), (p<0.001), respectively. Overlapping phenotypes correlated with LVEDD (Spearman’s-Rho-CC)=0.521, p<0.001; LVEF (Rho-CC)=−0.447, p<0.001 and LGE (Rho-CC)=0.472, p<0.001.ConclusionsThis study found there are many patients with overlapping phenotypes among NICMPs with dilated left ventricles. Overlapping phenotype was associated with greater LVEDD, lesser systolic function, and commonly existing LGE, which all impose increased cardiovascular risk. Linear midventricular LGE stripe was the most powerfully connected with loss of systolic function.

Effect of electrode configurations on piezoelectric vibration energy harvesting performance

Piezoelectric vibration energy harvesting is an attractive technology for self-powered wireless sensor networks because of the potential to deliver power to the sensor nodes from mechanical vibration sources in the surrounding medium. Systematic device designs are required in order to increase performance along with materials development of high piezoelectric coefficients and design of circuits with high power transfer efficiency. In this work, we present refined structural and electrical modeling of interdigitated electrodes (IDEs) for piezoelectric vibration energy harvesting, followed by parametric case studies on MEMS devices. Differences in geometric parameters including the size of the electrode and the number of IDE fingers for given device dimensions lead to substantial changes in harvesting performance such as capacitance, system coupling, voltage and power. When compared with parallel plate electrodes, use of IDEs results in much higher voltage generation by a factor of ten times while similar power levels are observed for both {3-1} and {3-3} configurations at optimal electrical loading conditions.

Geometry of the Internal Carotid Artery and Recurrent Patterns in Location, Orientation, and Rupture Status of Lateral Aneurysms: An Image-Based Computational Study

Intracranial aneurysm development and rupture may be associated to the morphology of the parent vessel. To quantitatively characterize the geometry of the internal carotid artery (ICA) in relation to the location and orientation of lateral aneurysms and to identify recurrent patterns associated with their rupture status. The geometry of 54 ICAs hosting lateral aneurysms was analyzed by means of computational geometry techniques. The ICA was split into individual bends, and the bend hosting the aneurysm was described in terms of curvature, torsion, length, and radius. Aneurysm position and orientation with respect to the parent vessel and specifically the hosting bend were characterized, as well as angles between the portions of the parent artery immediately upstream of and downstream from the aneurysm and the aneurysm ostium. Differences in geometric parameters with respect to rupture status and their performance as classifiers were evaluated. ICA bends hosting ruptured aneurysms were shorter with a smaller radius, lower maximum curvature, and lower proximal torsion compared with those hosting unruptured lesions. Ruptured aneurysms occurred in more distal portions of the ICA, along the outer wall of the vessel, and closer to the curvature peak within the hosting bend than unruptured ones. The proximal portions of ICAs hosting ruptured aneurysms approached the ostium region at a smaller angle. Geometric factors relative to the ICA were associated with the distribution of aneurysms and their rupture status. The present work has potential implications in the quest for hemodynamic factors contributing to the development, progression, and rupture of intracranial aneurysms.

Fracture surface analysis to understand the failure mechanisms of collagen degraded bone

Fracture surface analysis is a powerful technique to investigate bone failure mechanisms. Previously, emu tibiae were endocortically treated with 1M potassium hydroxide (KOH) solution for 14days. This treatment caused in situ collagen degradation rather than removal, with no differences in geometrical parameters, but with significant changes in mechanical properties. KOH-treated tibiae showed significant decreases in failure stress and increased failure strain and toughness. The fracture surfaces of untreated and 14-day KOH-treated failed specimens were examined to further identify differences in the failure process to explain the previously observed increase in toughness. Areas of 'tension,' 'compression,' and 'transition' were identified using digital images of the fracture surfaces. Within these areas, the degree of 'roughness' and 'smoothness' was identified and estimated, using an optical profiler and SEM images. The fracture surfaces of 14-day KOH-treated bones showed a significantly higher 'roughness' compared to untreated bones. Furthermore, additional toughening mechanisms, which are important features for dissipating energy during the failure process, were observed in KOH-treated samples, but were absent in untreated samples. These results indicate that the significant increase in toughness of KOH treated bones is the result of structural alterations that enhance the ability of the microstructure to dissipate energy during the failure process, thereby slowing crack propagation. Fracture surface analysis has helped explain why KOH-treated bones have increased toughness compared to untreated bones, namely via toughening mechanisms on the compressive failure side.

Molecular structure and conformational preferences of gaseous methylthiodichlorophosphite, Br2PSCH3, studied by gas electron diffraction and quantum-chemical calculations

Molecule Br2PSCH3 has been studied by gas electron diffraction method with the use of additional data of quantum-chemical data at the MP2/SDB-AUG-cc-PVTZ and B3PW91/6-311+G* (DFT) levels of theory. The structure optimization of Br2PSMe molecule by both theoretical methods (DFT/MP2) indicate that the most stable conformer is an anti conformer of Cs symmetry, while the energy of the second gauche conformer is by about 1.47/1.05 kcal mol−1 higher. Each conformer is characterized by dihedral angle τ(CSPlp) where lp denotes the direction of the lone electron pair on the P atom. The calculated standard free energies at 298.15 K indicate that the mole fractions in the gas phase at this temperature are: μ(anti) = 75/62%, μ(gauche) = 25/38%. Experimental ED data agree well with joint presence of both conformers in the ratio μ(anti) = 65(6)% and μ(gauche) = 35(6)%. Natural bond orbital analysis (NBO) testifies that anti-conformer is an example of stabilization of the form that is extremely unfavorable from the point of view of steric and electrostatic interactions. It is shown that relative stabilities of two conformers, differences in geometrical parameters, and several NBO descriptors are defined by effects of hyperconjugation, the most important of which is the πlpS→σ*(P-Br) interaction, namely, the delocalization of lone electron pair of π-type of the S atom into the antibonding orbital of P-Br bond.

Mechanism of bone collagen degradation due to KOH treatment

Background The mechanisms underlying the effect of alterations in type I collagen on bone mechanical properties are not well defined. In a previous study, male and female emu tibiae were endocortically treated with 1 M potassium hydroxide (KOH) solution for 1–14 days. This treatment resulted in negligible mass loss (0.5%), collagen loss (0.05%), no differences in geometrical parameters but significant changes in mechanical properties. The objective of this study was to determine the mechanism of collagen degradation due to KOH treatment in order to explain the previously observed mechanical property changes. Methods Bone mineral was assessed using x-ray diffraction (XRD), microhardness and backscattered electron imaging (BSE). Bone collagen was assessed using α-chymotrypsin digestion, differential scanning calorimetry (DSC), gel electrophoresis (SDS-PAGE) and polarized light microscopy (PLM). Results BSE, microhardness and XRD revealed no changes in bone mineral due to KOH treatment. DSC showed an altered curve shape (lower and broader), indicating a change in collagen organization due to KOH treatment. Decreased α-chain band intensity in 14-day KOH treated groups detected using SDS-PAGE indicated α-chain fragmentation due to KOH treatment. PLM images revealed differences in collagen structure in terms of pattern distribution of preferentially oriented collagen between the periosteal and endocortical regions. Conclusion These results suggest that endocortical KOH treatment causes in situ collagen degradation, which explains the previously reported altered mechanical properties. General significance Compromising the organic component of bone contributes to an increase in bone fragility.

Structure of 1-methyl-6-oxyquinolinium betaine dihydrate studied by X-ray diffraction, DFT calculations, vibrational and NMR spectra

The crystals of 1-methyl-6-oxyquinolinium betaine dihydrate, 6QB·2H 2O, are triclinic, space group P 1 ¯ . The oxygen atom of 6QB exhibits an extremely rare capability of accepting four hydrogen bonds. It is engaged in four hydrogen bonds to water molecules of the 2.823, 2.825, 2.833 and 2.849 Å; each water molecule interacts with two neighbouring 6QB molecules linking them into infinite sheets. Differences in geometrical parameters between the X-ray and calculated molecules reflect changes in their structures between zwitterion and quinonoid forms. The probable assignments of the experimental FTIR solid spectrum have been made on the basis of B3LYP/6-311G(d,p) calculated frequencies in vacuum. Both 1H and 13C chemical shifts are solvent dependent. Linear correlations between the experimental 1H and 13C NMR chemical shifts of 6QB·2H 2O in solutions and the GIAO/B3LYP/6-311G(d,p) calculated magnetic isotropic shielding tensors ( σ cal) using the screening solvation model, δ exp = a + bσ cal, are reported.

Self-Organization in Coordination-Driven Self-Assembly

Self-assembly allows for the preparation of highly complex molecular and supramolecular systems from relatively simple starting materials. Typically, self-assembled supramolecules are constructed by combining complementary pairs of two highly symmetric molecular components, thus limiting the chances of forming unwanted side products. Combining asymmetric molecular components or multiple complementary sets of molecules in one complex mixture can produce myriad different ordered and disordered supramolecular assemblies. Alternatively, spontaneous self-organization phenomena can promote the formation of specific product(s) out of a collection of multiple possibilities. Self-organization processes are common throughout much of nature and are especially common in biological systems. Recently, researchers have studied self-organized self-assembly in purely synthetic systems. This Account describes our investigations of self-organization in the coordination-driven self-assembly of platinum(II)-based metallosupramolecules. The modularity of the coordination-driven approach to self-assembly has allowed us to systematically study a wide variety of different factors that can control the extent of supramolecular self-organization. In particular, we have evaluated the effects of the symmetry and polarity of ambidentate donor subunits, differences in geometrical parameters (e.g., the size, angularity, and dimensionality) of Pt(II)-based acceptors and organic donors, the influence of temperature and solvent, and the effects of intermolecular steric interactions and hydrophobic interactions on self-organization. Our studies have shown that the extent of self-organization in the coordination-driven self-assembly of both 2D polygons and 3D polyhedra ranges from no organization (a statistical mixture of multiple products) to amplified organization (wherein a particular product or products are favored over others) and all the way to the absolute self-organization of discrete supramolecular assemblies. In many cases, inputs such as dipolar interactions, steric interactions, and differences in the geometric parameters of subunits, used either alone or as multiple factors simultaneously, can achieve absolute self-organization of discrete supramolecules. We have also observed instances where self-organization is not absolute and varies in its deviation from statistical results. Steric interactions are particularly useful control factors for driving such amplified self-organization because they can be subtly tuned through small structural variations. Having the ability to fully understand and control the self-organization of complex mixtures into specific synthetic supramolecules can provide a better understanding of analogous processes in biological systems. Furthermore, self-organization may allow for the facile synthesis of complex multifunctional, multicomponent systems from simply mixing a collection of much simpler, judiciously designed individual molecular components.

Vibrational spectra of the trifluoromethylsulfinate anion and scaled quantum mechanical force fields for CF3SO2− and CF3SeO2−

The infrared and Raman spectra of KCF3SO2 were obtained and the observed spectral features assigned to the expected normal modes of vibration. Besides, the vibrational properties of the CF3SO2− and CF3SeO2− related anions were studied by means of density functional theory (DFT) techniques. After obtaining the optimized geometrical parameters and conformations, the vibrational wavenumbers and the associated force constants were calculated. The original force fields in cartesian coordinates were transformed to local symmetry coordinates and subsequently scaled to reproduce the experimental wavenumbers. Some trends observed in the force constants of the studied species and of the related CF3SO3− anion could be explained by the differences in geometrical parameters.

3-Formyl-2-furanboronic acid: X-ray and DFT studies

The molecule of the title compound, C5H5BO4, is almost planar with the boronic acid group inclined to the furan ring by 3.7 (1)°. DFT (density functional theory) calculations at the B3LYP/6-311+G** level of theory (with no imaginary frequencies) were used to approximate the influence of hydrogen bonding on the molecular geometry and have confirmed the planarity of the mol­ecule. No significant differences in geometrical parameters in the solid state and in the gas phase are associated with the presence of the O—H⋯O intermolecular hydrogen-bonding network. The crystal packing is characterized by O—H⋯O hydrogen-bonded dimers, which are additionally linked by O—H⋯O, as well as C—H⋯O interactions, resulting in the formation of a three-dimensional network.

Neutral and ionic hydrogen bonding in Schiff bases.

Low-temperature, high-resolution X-ray studies of charge distributions in the three Schiff bases, the dianil of 2-hydroxy-5-methylisophthaldehyde, 3,5-dinitro-N-salicylidenoethylamine and 3-nitro-N-salicylidenocyclohexylamine, have been carried out. These structures exhibit interesting weak interactions, including two extreme cases of intramolecular hydrogen bonds that are ionic N(+)-H...O- and neutral O-H...N in nature. These two types of hydrogen bond reflect differences in geometrical parameters and electron density distribution. At the level of geometry, the neutral O-H...N hydrogen bond is accompanied by an increase in the length of the C(1)-O(1) bond, opening of the ipso-C(1) angle, elongation of the aromatic C-C bonds, shortening of the C(7)-N(2) bond and increased length of the C(1)-C(7) bond, relative to the ionic hydrogen bond type. According to the geometrical and critical point parameters, the neutral O-H...N hydrogen bond seems to be stronger than the ionic ones. There are also differences between charge density parameters of the aromatic rings consistent with the neutral hydrogen bond being stronger than the ionic ones, with a concomitant reduction in the aromaticity of the ring. Compounds with the ionic hydrogen bonds show a larger double-bond character in the C-O bond than appears in the compound containing a neutral hydrogen bond; this suggests that the electronic structure of the former pair of compounds includes a contribution from a zwitterionic canonical form. Furthermore, in the case of ionic hydrogen bonds, the corresponding interaction lines appear to be curved in the vicinity of the hydrogen atoms. In the 3-nitro-N-salicylidenocyclohexylamine crystal there exists, in addition to the intramolecular hydrogen bond, a pair of intermolecular O...H interactions in a centrosymmetric dimer unit.

Differential scanning calorimetry study of the hydrophobic hydration of the elastin-based polypentapeptide, poly(VPGVG), from deficiency to excess of water.

The polypentapeptide of elastin, poly(VPGVG), has become an interesting model polypeptide in understanding the mechanism of protein folding and assembly. Due to its simple amino acid composition and the predominance of apolar side chains, this polymer shows strong hydrophobic-hydration phenomena. This paper explores, by calorimetric methods, the nature and structure of the clathrate-like arrangements that take place, surrounding the apolar side chains of the polymer. The performance of these methods, especially differential scanning calorimetry, has a well-gained reputation. In this work, the development of the clathrate-like structures around this model polymer has been followed from water deficiency to water-excess states. Two main conclusions have been obtained from the data obtained. First, there is an upper limit of about 170 water molecules per pentamer as the number of water molecules required to form all the possible clathrate-like structures. Second, these structures exist as an inhomogeneous population with energies spreading in a significantly broad range, which is likely related to differences in geometrical parameters (bond lengths and angles) of the clathrate structure.

Relationships of mammalian sperm motility and morphology to hydrodynamic aspects of cell function.

This study investigated the relationships of sperm body morphology and flagellar beat frequency and shape with the swimming velocity, power output, and stirring of nearby fluid by the spermatozoa of several mammals. Hamster spermatozoa were studied before and after the motility activation which is associated with capacitation and the acrosome reaction in that species. Human spermatozoa were assessed while swimming progressively in semen, and also while exhibiting the figure-of-eight beat pattern seen in cervical mucus and other media of high viscosity. Ram spermatozoa were studied while swimming in diluted semen. Data obtained from high-speed cinemicrography were applied to a computerized mathematical model of the hydrodynamics of sperm movement. The results demonstrate the relationships between sperm hydrodynamics and morphology, flagellar beat frequency, and shape. Many of these relationships are highly nonlinear, so that small differences in geometrical parameters of morphology and movement can produce large differences in hydrodynamic characteristics. Thus, hamster spermatozoa (preactivated) swim faster and expend more energy than ram spermatozoa which, in turn, exceed human spermatozoa in these measures. However, there is sufficient geometrical similarity in the morphologies and movement characteristics of these spermatozoa that appropriate grouping of various parameters results in dimensionless expressions with general applicability. Thus, the conclusions resulting from the present work can be used in studying the spermatozoa of other mammals as well. It was also shown that fluid stirring by spermatozoa, as opposed to smaller microorganisms, is an important mechanism of transfer of dissolved ions, molecules, and gases to and from the cell surface. In this regard, activated hamster sperm stir substantially more fluid than do preactivated hamster sperm, even though their power outputs are not significantly different.