Orientation Angle Research Articles

Retention and interfacial failure mechanism of single diamond grains in resin-bonded grinding tools

Abrasive grains and the associated bonding agent are the two significant components in the manufacturing of fixed abrasive machining tools. The material properties and interfacial bonding behavior between the grains and the bonding matrix determine machining performance. In precision machining processes with diamond abrasives, the primary failure modes of fixed abrasive tools are grain dislodgement and premature loss, leading to abrupt change in machining load and ultimately causing inaccurate and inefficient machining performance. This study develops a comprehensive model for understanding abrasive grain retention and interfacial failure mechanisms in resin-bonded diamond tools. Finite element analysis of a single diamond grain embedded in a resin matrix was conducted to examine the influence of the grain shape, protruding height, and orientation angle on critical interfacial failure force. A series of single diamond scratching experiments validated the model, revealing that the maximum retention force reached 43.56 N for grains with a 0.9 mm protruding height and a 60° orientation angle. The results also show that, within a specific grain size range, grain shape—quantified by the sphere deviation coefficient proposed in this paper, has the greatest impact on retention and failure behavior. Protruding height plays a secondary role, while the contribution of orientation angle is minimal. These findings provide valuable insights for the design, manufacture, and optimization of precision abrasive machining tools, particularly for applications requiring high precision and reliability.

Statistical Modeling and Probable Calculation of the Strength of Materials with Random Distribution of Surface Defects

Based on the solutions of deterministic fracture mechanics and the methods of probability theory, the algorithm for calculating the probabilistic strength characteristics of plate elements of structures with an arbitrary stochastic distribution of surface defects is outlined. On the plate surface, there are uniformly distributed cracks that do not interact with each other, the plane of which is normal to the surface, and the depth is much less than its length on the surface. The cracks’ depth and angle of orientation are random values, and their joint distribution density is specified. Plates made of this material are under the influence of biaxial loading. The probability of failure, along with the mean value, the dispersion, and the variation coefficient of the plate’s strength, taking into account the surface defects under different types of stress, were determined. Their dependence on the type of loading, the size of the plate, and the surface structural heterogeneity of the material were studied graphically. Joint consideration of the influence of the interrelated properties of real materials, such as defectiveness and stochasticity, on strength and fracture, opens up new opportunities in creating a theory of strength and fracture of deformable solids.

Effect of Printing Orientation on the Mechanical Properties of Low-Force Stereolithography-Manufactured Durable Resin

This study presents the results of fracture toughness tests conducted on specimens obtained by additive manufacturing techniques, specifically using low-force stereolithography. The samples were manufactured from a transparent 3D printing material for biocompatible applications, the so-called BioMed Durable Resin, which is a Formlabs-patented polymer material that simulates the strength and rigidity of polyethylene. The selected toughness tests in this context were performed following the ASTM D5045-99 guidelines. All tests were conducted under controlled laboratory conditions at 23 °C and 50% relative humidity, ensuring adherence to the standard and the replicability of the experimental results. To investigate the influence of printing plane orientation, specimens were produced at three printing orientation angles (0, 45, and 90 degrees). These angles were selected to provide a comprehensive evaluation of the anisotropy effects in the material. They cover both extreme orientations (0° and 90°) and include an intermediate value (45°), allowing us to assess variations in mechanical behavior across a representative range of printing orientations, consistent with prior research in the field. The experimental tests yielded data on the crack resistance and energy release rate for each angle of orientation. There are various implications of the findings, beyond materials engineering, for applications in biomedicine. Indeed, this same approach opens the door to new research methods for manufacturing certified biocompatible materials from such durable resins. Finally, complementary issues such as related medical applications have been slightly addressed for future work, since biomedicine innovation clusters can contribute to accelerating growth in this crucial field for productive sector activity and the local business environment.

Influence of the rigidity of the backbone and arms on the dynamical and conformational properties of the comb polymer in shear flow.

The dynamical and conformational properties of the comb polymer with various rigidities of the backbone and arms in steady shear flow are studied by using a hybrid mesoscale simulation approach that combines multiparticle collision dynamics with standard molecular dynamics. First, during the process of the comb polymer undergoing periodic tumbling motion, we find that the rigidity of the arms always promotes the tumbling motion of the comb polymer, but the rigidity of the backbone shifts from hindering to promoting it with increasing the rigidity of the arms. In addition, the comb polymer transitions from vorticity tumbling to gradient tumbling with the increase in shear rate. Second, the range of variation of the end-to-end distance of the backbone and the average end-to-end distance of the arms increases with the increase in the rigidity of the arms and backbone, respectively, and the range of both changes grows with the increase in shear rate. Furthermore, as the rigidity increases, the moldability of the comb polymer decreases and the orientation angle of the comb polymer increases.

Self-Repairable Carbon Fiber-Reinforced Epoxy Vitrimer Actuator with Multistimulus Responses and Programmable Morphing.

Smart shape-changing structures in aerospace applications are vulnerable to damage in harsh environments. Balancing high mechanical performance with self-repair capabilities poses a challenge due to inherent trade-offs between strength and flexibility. To address this challenge, an asymmetric bilayer-structured actuator was fabricated using commercially available continuous carbon fiber tows (CFs) as the passive layer and a dynamic cross-linked epoxy vitrimer as the active layer. The construction of the vitrimer-CF actuator involves a simple and scalable hot-pressing process, resulting in a tensile strength of 234 MPa and an interfacial bonding strength of 405 N·m-1. This actuator exhibits remarkable deformation capability (210°/7 s) and an efficient self-repair ability under various stimuli, including thermal (60-160 °C), light (0.4-1.0 W·cm-2), electric (2-4 V), and solvent (acetone). By adjustment of the orientation angle of CFs, complex left-handed and right-handed curling structures can be achieved. Leveraging the insights from photothermal/electrothermal actuation mechanisms, a quadruped crawling robot is developed capable of crawling 4 cm with a single light illumination. The actuator can lift objects 45 times its weight when subjected to light stimuli. Additionally, a flap actuator is constructed to achieve an angle change of 63° within 10 s under an electric stimulus, enabling remote control over the aircraft flight angle. These results demonstrate the potential of the vitrimer-CF actuator for advanced applications in intelligent aerospace structures.

Structure Design on Thermoplastic Composites Considering Forming Effects.

Carbon fiber reinforced polypropylene (CF/PP) thermoplastics integrate the superior formability of fabrics with the recoverable characteristics of polypropylene, making them a pivotal solution for achieving lightweight designs in new energy vehicles. However, the prevailing methodologies for designing the structural performance of CF/PP vehicular components often omit the constraints imposed by the manufacturing process, thereby compromising product quality and reliability. This research presents a novel approach for developing a stamping-bending coupled finite element model (FEM) utilizing ABAQUS/Explicit. Initially, the hot stamping simulation is implemented, followed by the transmission of stamping information, including fiber yarn orientation and fiber yarn angle, to the follow-up step for updating the material properties of the cured specimen. Then, the structural performance analysis is conducted, accounting for the stamping effects. Furthermore, the parametric study reveals that the shape and length of the blank holding ring exerted minimal influence on the maximum fiber angle characteristic. However, it is noted that the energy absorption and crushing force efficiency metrics of the CF/PP specimens can be enhanced by increasing the length of the blank holding ring. Finally, a discrete optimization design is implemented to enhance the bending performance of the CF/PP specimen, accounting for the constraint of the maximum shear angle resulting from the stamping process. The optimized design resulted in a mass reduction of 14.3% and an improvement in specific energy absorption (SEA) by 17.5% compared to the baseline sample.

A Deep Learning Biomimetic Milky Way Compass.

Moving in straight lines is a behaviour that enables organisms to search for food, move away from threats, and ultimately seek suitable environments in which to survive and reproduce. This study explores a vision-based technique for detecting a change in heading direction using the Milky Way (MW), one of the navigational cues that are known to be used by night-active insects. An algorithm is proposed that combines the YOLOv8m-seg model and normalised second central moments to calculate the MW orientation angle. This method addresses many likely scenarios where segmentation of the MW from the background by image thresholding or edge detection is not applicable, such as when the moon is substantial or when anthropogenic light is present. The proposed YOLOv8m-seg model achieves a segment mAP@0.5 of 84.7% on the validation dataset using our own training dataset of MW images. To explore its potential role in autonomous system applications, we compare night sky imagery and GPS heading data from a field trial in rural South Australia. The comparison results show that for short-term navigation, the segmented MW image can be used as a reliable orientation cue. There is a difference of roughly 5-10° between the proposed method and GT as the path involves left or right 90° turns at certain locations.

Analytical investigation of green composite lamina utilizing natural fiber to strengthen PLA

This work’s main goal is to investigate the effects of the natural fiber orientation angle on the lamina’s engineering constants, such as the shear modulus, major Poisson’s ratio, longitudinal and transverse Young’s moduli, and lamina level shear coupling coefficients. The PLA matrix of the three green composite laminas under study is reinforced with natural fiber. The three natural fibers under study are flax, jute, and bamboo fibers. The study assesses the performance of three PLA laminas reinforced with natural fibers for each of the previously listed engineering constants. The behavior of the green composite lamina for various fiber volume fractions is also presented in this study. This analytical investigation employs the macromechanics of lamina to do the examination. The investigation’s findings demonstrated that the volume % and fiber orientation have a considerable impact on the lamina’s engineering constants. The study offers a comprehensive variation of the lamina’s engineering constants for each fiber orientation angle between 0 and 90° and for each fiber volume fraction between 0 % (entirely matrix) and 100 % (completely fibers) in steps of 5 %. The outcomes of the presented study will help in the design of the facesheets for the composite sandwich structures. The results presented can be used to check the viability of using natural fibers to strengthen different polymer matrices. Bamboo-PLA lamina outperforms flax-PLA and jut-PLA laminae.

Evolution of Rotating Internal Channel for Heat Transfer Enhancement in a Gas Turbine Blade

To achieve higher thermal efficiency in a gas turbine, increasing the turbine inlet temperature is necessary. The rotor blade at the first stage tolerates the highest temperature, and the serpentine internal channel located in the middle chord of the rotor blade is vital in guaranteeing the blade’s service life. Therefore, it is essential to illustrate the evolution of the rotating internal channel in a gas turbine blade. In the paper, the influence of the Coriolis force, including its mechanisms, on the conventional rotating channel are reviewed and analyzed. A way to utilize the positive heat transfer effect of the Coriolis force is proposed. Recent investigations on corresponding novel rotating channels with a channel orientation angle of 90° (called bilaterally enhanced U-channels) are illustrated. Moreover, numerical investigations about the Re effects on bilaterally enhanced smooth U-channels were carried out in the study. The results indicated that bilaterally enhanced U-channels can utilize the Coriolis force positive heat transfer effect on the leading and the trailing walls at the same time. Re and Ro are vital non-dimensional numbers that influence the performance of bilaterally enhanced U-channels. Re and Ro have an independent influence on the heat transfer performance of the bilaterally enhanced U-channel. Ro is good for the heat transfer of the bilaterally enhanced U-channel on both the leading and the trailing walls. Therefore, the bilaterally enhanced U-channel is suitable for application in the middle chord region of a turbine blade, since it can utilize the rotation effect of the rotating blade to improve the heat transfer ability of the blade and thus reduced the blade temperature. At the same Ro, Re positively affects the Nu on the leading and the trailing walls of the Coriolis-utilization rotating smooth U-channel, but plays a negligible role on Nu/Nu0.

Uniaxial Molecular Alignment in Thin Films Composed of Discrete NDI‐T2 Oligomers Investigated by Variable‐Angle Spectroscopic and Imaging Ellipsometry

The understanding of the optical characteristics and the influence of thermally induced crystallization is vital to evaluate newly synthesized organic semiconductors for their potential applications. Variable‐angle spectroscopic ellipsometry (VASE) is employed to determine the complex dielectric function of two recently developed discrete oligomers based on naphthalene diimide (NDI) and bithiophene (T2), applying an anisotropic optical model. It is shown that the as‐cast films are optically near‐isotropic, while the annealed films exhibit pronounced anisotropies with respect to the orientation of the π−π* transition. Differences between the two distinct molecules are observed and discussed. The degree of optical anisotropy is quantified using the average molecular orientation angle φ, associated with the orientation of the π−π* transition dipole, and the related orientation order parameter S. The molecules are shown to form crystallites of several microns in size upon annealing. Imaging ellipsometry is thus additionally employed to study their optical anisotropy on a microscopic scale, and the agreement with results from macroscopic measurements is evaluated.

Method of understanding for investigation of crack propagation trajectory and fracture aspects in dental cracks on view of fracture mechanics theories.

Current research introduces understanding of dental-cracks mechanistic with fundamental fracture behavior in natural-teeth and orthodontics including mode I crack under both tension and compression, mode II crack under both clockwise-shear and anticlockwise-shear and mixed-mode cracks under both compression-shear and tension-shear. It depends on experimental models of transparent-Plexiglas including pre-cracks of different orientations angle (b) based on fundamental theoretical fracture analysis with comparison. Problem-concept, cracking aspects of fracture-initiation, propagation-direction, fracture-increment length, critical external-load and fracture path are predicted experimentally and theoretically using directional fracture approach and directional strain-energy density theory. Tests are carried out for (36) samples for compression and tension in LEFM. Friction-resistance between crack-surfaces is considered with derivation of equations and charts. Negative stress-intensity factor (-KI) is developed for solving complicated problems of cracks under occlusal compression loads. The occlusal loads are compression and shear producing lateral tensile mixed mode cracks. The critical propagation angle (qc), critical propagation load (sc) and critical propagation envelope of stress intensity factors (KI-KII) are developed with respect to crack orientation angle (b) with comparisons. They are necessary to predict the fracture propagation early before teeth-failure. It helps for prevention and control of dental-cracks, correct-restoration, prosthodontics, orthodontics, and development of new dental-materials and technologies.

Application of Surface Ultrasonic Waves for Detection of Contact Fatigue Cracks in the Rail Surface

The integrity and durability of rails plays a key role in train safety. However, the interaction of the rail head surface with the wheels of the rolling stock leads to high damage to these areas. The surface of the rail head is subject to the greatest damage, in which fatigue cracks develop on the surface with subsequent development. Timely detection of fatigue cracks in the rolling surface is possible using the ultrasonic technique using surface waves. To do this, the work investigated the sensitivity of a surface ultrasonic wave to obstacles in the surface of rails in the form of extended grooves, notches of finite length and known depth, as well as real cracks. The studies were carried out using the pulse-echo method at frequencies of 1.25, 1.8, 2.5, 4 MHz. Research has shown that surface waves are sensitive to surface fatigue cracks. The amplitude of the reflected pulses depends on the wavelength and the depth of crack propagation. The influence of the distance to fatigue cracks and the orientation angle of the transducer relative to the rail axis on the sensitivity of the surface wave to these defects was also studied. The results obtained allow us to conclude that the use of surface ultrasonic waves makes it possible to detect fatigue cracks in the crack surface. Thus, the use of the pulse-echo technique and surface wave converters makes it possible to detect contact fatigue cracks in the rail head, which can be used to eliminate them in a timely manner. The determination of their depth by amplitude is influenced by many factors, which are difficult to take into account in real conditions.

Synergistic corrosion inhibition of 4-hydroxypyridine and halogen ions: Insights from interfacial nonlinear spectroscopy.

4-Hydroxypiridine (4-HPy) is a green chemistry corrosion inhibitor for low-carbon steel, valued for its environmental compatibility and low toxicity. Despite lower initial effectiveness than 4-mercapto/4-aminopyridine, 4-HPy's performance is markedly enhanced by halogen ions. By employing second harmonic generation (SHG) spectroscopy combined with electrochemical methods, Raman spectroscopy, atomic force microscopy, x-ray photoelectron spectroscopy, and in situ UV spectroscopy, this study elucidates the synergistic enhancement mechanism of 4-HPy with Cl-, Br-, and I- in 0.5 mol/L HCl solution. Time-dependent SHG measurements showed a two-step process of rapid adsorption and subsequent orientation change, with a proposed mechanism to interpret the temporal changes in SHG intensity. Deducing the adsorption kinetic equations and their application to the experimental data yields the adsorption rate (kad) and orientation change rate (Kre). Halogens reduce the orientation angle of 4-HPy, facilitating its adsorption on the substrate surface and effectively inhibiting corrosion via distinct mechanisms. Cl- and Br- ions primarily adsorb onto the metal surface, forming an adsorption film that not only enhances the subsequent adsorption of 4-HPy but also provides a protective effect for the metal surface. Conversely, I- forms mainly complexes with 4-HPy in solution, co-adsorbs onto the metal surface, and demonstrates a significant synergistic effect. This study revealed the synergistic efficacy hierarchy among halogen ions, with the order 4HPy + NaCl < 4HPy + NaBr < 4HPy + NaI. This study enhances our molecular-level understanding of the synergistic mechanism between halogen ions and corrosion inhibitors and provides valuable insights for designing and developing effective corrosion inhibitors.

Geometric characteristics of stromal collagen fibres in breast cancer using differential interference contrast microscopy.

Breast cancer (BC) is characterised by a high level of heterogeneity, which is influenced by the interaction of neoplastic cells with the tumour microenvironment. The diagnostic and prognostic role of the tumour stroma in BC remains to be defined. Differential interference contrast (DIC) microscopy is a label-free imaging technique well suited to visualise weak optical phase objects such as cells and tissue. This study aims to compare stromal collagen fibre characteristics between in situ and invasive breast tumours using DIC microscopy and investigate the prognostic value of collagen parameters in BC. A tissue microarray was generated from 200 cases, comprising ductal carcinoma in situ (DCIS; n=100) and invasive tumours (n=100) with an extra 50 (25 invasive BC and 25 DCIS) cases for validation was utilised. Two sections per case were used: one stained with haematoxylin and eosin (H&E) stain for histological review and one unstained for examination using DIC microscopy. Collagen fibre parameters including orientation angle, fibre alignment, fibre density, fibre width, fibre length and fibre straightness were measured. Collagen fibre density was higher in the stroma of invasive BC (161.68±11.2fibre/µm2) compared to DCIS (p<0.0001). The collagen fibres were thinner (13.78±1.08µm), straighter (0.96±0.006, on a scale of 0-1), more disorganised (95.07°±11.39°) and less aligned (0.20±0.09, on a 0-1 scale) in the invasive BC compared to DCIS (all p<0.0001). A model considering these features was developed that could distinguish between DCIS and invasive tumours with 94% accuracy. There were strong correlations between fibre characteristics and clinicopathological parameters in both groups. A statistically significant association between fibre characteristics and patients' outcomes (breast cancer specific survival, and recurrence free survival) was observed in the invasive group but not in DCIS. Although invasive BC and DCIS were both associated with stromal reaction, the structural features of collagen fibres were significantly different in the two disease stages. Analysis of the stroma fibre characteristics in the preoperative core biopsy specimen may help to differentiate pure DCIS from those associated with invasion.

Programmable multi-wavelength distributed feedback laser array integrated in a liquid crystal polymer waveguide.

Liquid crystal (LC) distributed feedback (DFB) lasers hold significant potential for integrated photonics applications. However, limitations in wavelength spacing for wavelength switching, device size, and compatibility with other technologies have impeded advancements of the LC DFB laser in integration and responsiveness. Herein, we propose a thin-film multi-wavelength DFB laser array utilizing high-resolution patterned programmable nematic LC polymers, enabling rapid switching with high-resolution wavelength spacing between wavelength division multiplexing channels while maintaining a stable single longitudinal mode (SLM) for each laser. The underlying physical mechanism involves modulating the effective refractive index of the DFB laser by varying the LC molecules' orientation angles between adjacent regions of the LC grating to achieve wavelength modulation. Additionally, a specialized LC waveguide design connects the DFB lasers, facilitating wavelength modulation as well as straight-line and bending propagation of the laser. Furthermore, the laser array demonstrates a relatively low energy threshold, facilitating its applications in high-integration scenarios.

A Method to Estimate Solar Panel Orientation Effectivity

Abstract In the past years, new photovoltage (solar panel) systems have been installed rapidly, for instance, in regular households. Investment decisions have often been made without knowing all technical facts and information, which are affecting total energy production of photovoltage systems. In this work, we have made a simple model, which shows solar panels energy production with the different orientation angles of solar panel. Our results show that if panels are installed more than 30 degrees from the optimal orientation, the energy production drops drastically. This result applies to both azimuth and tilt angles. The developed model is very adaptive, and it can use any locations and all orientation angles. We confirm our calculation result by making a measurement with a small (30 W) test solar panel. The model and measurement results have a good relationship (correlation coefficient, R 2 = 0.7). The obtained result is satisfactory by taking into account the fact that measurements were made during the variable weather conditions and over long period of time (six months).

SLMAP3 is crucial for organogenesis through mechanisms involving primary cilia formation.

SLMAP3 is a constituent of the centrosome and is known to assemble with the striatin-interacting phosphatase and kinase (STRIPAK) complex, where it has been reported to repress Hippo signalling. The global knockout of SLMAP3 in mice results in embryonic/perinatal lethality and stunted growth without changes in the phosphorylation status of YAP. Diverse phenotypes present in the SLMAP3-/- embryos include reduced body axis, small and abnormal organs resembling defects in planar cell polarity (PCP) signalling, while also displaying the notable polycystic kidneys, a known manifestation of ciliopathies. Analysis of cell polarity in primary mouse embryonic fibroblasts (MEFs) including cell migration, orientation and mitotic spindle angle did not reveal any changes due to SLMAP3 loss in these cells, although the expression of DVL3 was significantly reduced. Furthermore, MEFs lacking FGFR1OP2 or STRN3, two other STRIPAK members, did not reveal any significant changes in any of these parameters either. Significant changes in the number of ciliated cells and primary cilium length in SLMAP3 and FGFR1OP2 deficient MEFs were evident, while a reduced primary cilium length was notable in chondrocytes of SLMAP3 deficient embryos. Our findings suggest that SLMAP3 is essential for mouse embryogenesis through novel mechanisms involving the primary cilium/PCP and protein stability independent of Hippo signalling.

Prediction of impulse waves generated by partially submerged landslides with a low Froude number based on prototype physical experiments

Impulse waves generated by landslides are a potential threat to reservoirs. Wave prediction formulas that can quickly assess the hazards and extent of landslide-induced waves are an important means for early warning and disaster prevention and mitigation. Partially submerged landslides often generate landslide waves with low Froude numbers. There is limited research on prediction formulas for such waves, and most studies focused on specific wave propagation stages rather than forming a comprehensive formula system. In this study, three typical low Froude number submerged landslides that occurred in the Baihetan reservoir were selected as prototypes, and a large-scale three-dimensional (3D) physical model experiment field with dimensions of 30 × 29.5 × 1.5 m3 was constructed. A total of 95 experiments were performed. The entire process of impulse wave generation in the reservoir area was investigated by dividing the waves into four successive stages: initiation, rapid circular attenuation propagation, progressive attenuation propagation along the channel, and wave run-up. Based on a large amount of physical experimental data, formulas were derived for the maximum wave amplitude, propagation wave amplitude considering the degree of landslide submergence, and impulse wave run-up considering the shore slope orientation and ravine angle. These formulas were combined to form a comprehensive formula system to calculate the whole process of the impulse waves generated by the landslide in the narrow river channel with a wide influence range. The comprehensive formula system was applied to typical representative landslide experiments, and its accuracy was analyzed; the prediction accuracy ranged from 56% to 89.5%. This study can serve as a reference for assessing the risk of impulse waves generated by landslides in reservoir areas.

Influence of Rectangular Micro Inserts and Micro Chambers Heat Transfer Characteristics of Microchannel Heat Exchanger

This decade's smaller gadgets have made heat removal in electronics and microprocessors increasingly crucial necessitating the use of micro channel heat exchangers (MCHEs). The current study investigates the MCHE performance improvement through micro chambers and rectangular inserts with varying orientations (angle of insert: 0˚, 45˚, and 90˚). Experimental and numerical studies are conducted in a laminar environment, with Reynolds number varying from 74 to 446. Simulation of fluid flow and heat transfer is accomplished through Finite Volume Method. Thermal performance indicators, fluid flow parameters, pressure drop, friction factor, are used to evaluate and quantify the efficiency of MCHEs. It is shown that inserting two rectangles at 90° angle can achieve the ideal heat transfer coefficient. As a result, compared to the MCHE-MCDCI with various orientations of 0°, 45°, and 90°, respectively, the increase in Nu is 12.21%, 23.42%, and 37.10%, respectively. The rectangular insert at an angle of 90 in an MCHE caused the highest pressure loss. In contrast with MCHE-MCDCI. The pressure drop at 0˚, 45˚, and 90˚ increases by 13.26%, 37.94%, and 52.70%, respectively. When compared with double cylindrical inserts, MCHEs with rectangular inserts that are orientated at an angle of 90 degrees produced the greatest PEC.

Effects of build orientation angles on temporary prosthesis

Effects of build orientation angles on temporary prosthesis