Disk Mode Research Articles

Regulated cell death: Implications for intervertebral disc degeneration and therapy.

Intervertebral disc degeneration (IDD) is the major source of chronic low back pain. As a controllable biological process, regulated cell death (RCD) extensively participates in the pathogenesis of IDD. Nevertheless, the initiation and progression of RCD remain unclear, and more importantly, the interaction between different RCD modes during IDD and therapy is far from well understood. Literature search was performed using "regulated cell death AND intervertebral disc degeneration" in PubMed, Embase, and Web of Science. Meanwhile, relevant findings have been reviewed and quoted. In this review, we discuss the inducing factors of IDD, various modes of RCD in intervertebral disc, the interactions between different RCD modes, as well as the obstacles to achieve disc regeneration. Meanwhile, the research gaps and perspective in studies that targeting RCD are also presented. Increasing evidence demonstrated the presence of different RCD modes in intervertebral disc during the progression of IDD. RCD in the resident disc cells is probably induced by the multiple factors such as abnormal mechanical loading, nutritional imbalance, inflammation microenvironment, circadian rhythm changes, withdraw of hormones, and other biomechanical factors. A better understanding of the fundamental mechanisms and the interactions between different RCD modes might contribute to the rescuing of disc degeneration and development of promising therapeutics. The Translational potential of this article. This review aims to demonstrate a better understanding of the fundamental mechanisms governing RCD, which might contribute to the rescuing of disc degeneration and to the development of promising therapeutics in a clinical setting.

Optical measurement of a quantum dot state in a microdisk by a Stark transducer

A spectroscopic method for determining the number of electrons in a quantum dot (QD) located inside a microdisk resonator is proposed. A transducer with the form of a ring structure composed of single-electron QDs is an auxiliary element used to enhance the interaction of laser photons with the QD and with the microdisk. The microdisk parameters are calculated to ensure an efficient energy exchange between the disk modes and the transducer QDs. The influence of the Stark and Förster effects on the measurement accuracy is studied. The optimal measurement regime is shown to be achieved provided that both effects are compensated.

Mesoscale Study on Splitting Tensile Damage Characteristics of Concrete Based on X-ray Computed Tomography and Digital Image Correlation Technology.

In this paper, the mesoscale damage properties of concrete and mortar were studied experimentally under Brazilian disc splitting tensile tests combining X-ray computed tomography (CT) and digital image correlation (DIC) technology. Considering the factors of water/cement ratios and loading rates, the influence of meso components on the macro tensile properties and failure modes of concrete were studied. The experimental results and analysis indicate that the following: (1) the existence of coarse aggregate makes the tensile strength of concrete lower than that of mortar and reduces the sensitivity of tensile strength to the loading rates; (2) the failure modes of mortar and concrete Brazilian discs differ in the crack initiation positions and localization phenomena. Under high loading rates, the local failure plays a critical role in the strength improvement of concrete; (3) for concrete, interface failure and mortar failure are the main failure modes under low loading rates, whereas aggregate failure gradually becomes the main failure mode with increasing loading rates. The decrease in water/cement ratios improves the strength of the mortar matrix and interfacial bonding performance, leading to more serious aggregate damage and higher strength.

Terahertz-range plasmon and whispering gallery mode resonances in the plane wave scattering from thin microsize dielectric disk with graphene covers

We analyse the scattering and absorption of a terahertz-range plane wave by a thin circular dielectric disk with two graphene covers. Assuming that the thickness of the whole composite disk is much smaller than the free-space wavelength, we reduce the complexity of the problem with the aid of the generalized boundary conditions. This yields a set of singular integral equations for the effective electric and magnetic currents, induced on an equivalent zero-thickness disk. The adopted advanced numerical solution technique is a version of the method of analytical preconditioning, which uses weighted polynomials as expansion functions in the discretization of the integral equations. Then, the resulting matrix equation has Fredholm second-kind property that enables us to control the computational error by the matrix size and reduce it to the desired level. This accurate analysis reveals resonances on several types of natural modes, best understood via visualization of in-resonance near-fields. They are the plasmon-mode resonances of the graphene disk, perturbed by the presence of the dielectric filler, and the dielectric disk modes, perturbed by the graphene covers. Additionally, quasi-full disk transparency is observed if the transverse resonance condition is fulfilled. Special attention is paid to the tunability of the found effects with the aid of graphene's chemical potential.

Directional emission in X-cut lithium niobate microresonators without chaos dynamics

We systematically investigate the field distribution of the transverse electric modes in X-cut lithium niobate disks as an example of circular microcavities with anisotropic refractive index. A conserved quantity is discovered, which indicates the absence of chaos that generally exists in deformed microcavities and leads to a nontrivial directional emission. The emission directionality was theoretically investigated and experimentally verified by exciting high-order modes of an X-cut lithium niobate microresonator assisted with second harmonics. The field distribution analysis can enrich the knowledge in designing photonic devices that need precise control of field distribution, such as phase matching in nonlinear processes. Furthermore, the discovered emission phenomenon is momentous in enhancing and controlling communications between on-chip photonic devices.

Multiple Fano resonances in gold split ring disk dimers

A plasmonic dimer composed of a gold split ring and a gold disk is proposed. The scattering spectra and electromagnetic field distributions on the surface of the dimer are calculated by the finite difference time domain method, and the effects of split gap orientation and structural symmetry breaking of the ring on Fano resonance characteristics are theoretically investigated in detail. The results show the multiple Fano resonances that can be formed due to the destructive interference between the electric dipole mode of the disk and multiple multipolar modes of the split ring, and the red shift when the symmetry breaking of the split ring is broken. When the split gap of the ring is parallel to the interparticle axis of the dimer, multiple Fano resonances based on the odd-order mode and the even-order mode of the split ring can be generated, and more even-order Fano resonances can be formed due to the further symmetry breaking of the split ring. In addition, a more refined scattering spectrum can be obtained as the ring internal surface moves far away from the disk along the interparticle axis. On the other hand, Fano resonances based on the lower order multipolar modes of the ring can be increased as they move away from the split gap. When the split gap of the ring is perpendicular to the interparticle axis of the dimer, only the even-order Fano resonances can be excited, and these resonances increase with the ring internal surface going away from the disk no matter whether the split gap of the ring faces the disk or not. As the structural symmetry of the dimer is further broken due to the ring internal surface moving along the split gap direction, the odd-order Fano resonance can be successfully produced in the dimer with the split gap coming back to the disk, at the same time, the even-order Fano resonances are gradually weaken perhaps due to the complicated competitive behaviors of spectral overlapping between the dipole mode of the disk and multipolar mode of the ring in energy. However, there is no odd-order Fano resonance appearing in the dimer with the split gap facing the disk except for a slightly increased even-order Fano resonance, as the structural symmetry of the dimer is further broken. These results are expected to be useful in designing multiple Fano controllable split ring disk dimers and also developing the application of multiwavelength micro-nano photonics.

Retinal microvascular changes in patients with familial mediterranean fever: a study based on optical coherence tomography angiography

Purpose: In this study, we aimed to show whether a difference exists between retinal and choroidal microcirculation findings between patients with familial Mediterranean fever and healthy controls. Methods: Thirty-two patients with familial Mediterranean fever and 30 healthy controls were included in the study. All the patients underwent a complete ophthalmologic examination, including best-corrected visual acuity and intraocular pressure measurement. The AngioVue optical coherence tomography angiography device (Optovue, Fremont, CA) with split-spectrum amplitude-decorrelation angiography was used to evaluate and examine the retinal microvascular structure. Three-dimensional en face Optical coherence tomography angiography images were obtained by examining the macula using the 3 x 3 mm scanning protocol in the Angio Retina mode and the optic nerve using the 3 x 3 mm scanning protocol in the Angio Disk mode. All the patients’ right eyes were examined. Results: A total of 62 subjects were included in the study, of whom 32 (53.3%) were female and 30 (46.7%) were male. No statistically significant difference was found between the two groups in terms of optic nerve head or radial peripapillary capillary vessel density. On examination, the superficial capillary plexuses were statistically similar between the two groups, but the deep capillary plexus vessel density in the parafovea, superior hemi, temporal, and superior areas were significantly lower in the patients with familial Mediterranean fever. Conclusions: We found that the capillary plexus vessel density was significantly lower in the parafovea, superior hemi, temporal, and superior regions in the patients with familial Mediterranean fever than in the control group. Therefore, OCTA, a noninvasive study, may be useful for understanding the systemic effects of familial Mediterranean fever.

Retinal microvascular changes in patients with familial mediterranean fever: a study based on optical coherence tomography angiography.

In this study, we aimed to show whether a difference exists between retinal and choroidal microcirculation findings between patients with familial Mediterranean fever and healthy controls. Thirty-two patients with familial Mediterranean fever and 30 healthy controls were included in the study. All the patients underwent a complete ophthalmologic examination, including best-corrected visual acuity and intraocular pressure measurement. The AngioVue optical coherence tomography angiography device (Optovue, Fremont, CA) with split-spectrum amplitude-decorrelation angiography was used to evaluate and examine the retinal microvascular structure. Three-dimensional en face Optical coherence tomography angiography images were obtained by examining the macula using the 3 x 3 mm scanning protocol in the Angio Retina mode and the optic nerve using the 3 x 3 mm scanning protocol in the Angio Disk mode. All the patients' right eyes were examined. A total of 62 subjects were included in the study, of whom 32 (53.3%) were female and 30 (46.7%) were male. No statistically significant difference was found between the two groups in terms of optic nerve head or radial peripapillary capillary vessel density. On examination, the superficial capillary plexuses were statistically similar between the two groups, but the deep capillary plexus vessel density in the parafovea, superior hemi, temporal, and superior areas were significantly lower in the patients with familial Mediterranean fever. We found that the capillary plexus vessel density was significantly lower in the parafovea, superior hemi, temporal, and superior regions in the patients with familial Mediterranean fever than in the control group. Therefore, OCTA, a noninvasive study, may be useful for understanding the systemic effects of familial Mediterranean fever.

Fatigue reliability and sensitivity analysis of turbine disk with fuzzy failure status

Low-cycle fatigue is typical failure mode of aero-engine turbine disk, traditional reliability analysis method based on the binary state assumption has certain limitations for turbine disk reliability evaluation, because it doesn't consider the change of damage strength parameter caused by loading sequences and the enhanced damage by small load. On the basis of fatigue reliability analysis of the turbine disk, this paper considers the fuzzy state assumption of turbine disk, then select the membership function and indicate fuzzy failure probability of turbine disk, which can be transformed into a series of conventional failure probability by Gaussian quadrature. An active learning Kriging model is used to orderly calculate the failure probability corresponding to different limit state functions and the fuzzy failure probability of turbine disk. A global sensitivity index based on fuzzy failure probability is established to analyze the influence of input variables on the fuzzy failure probability, which is helpful to the reliability design and structural optimization of the turbine disk.

The Effect of Loading Rate on Fracture Toughness of Concrete using Type I Fracture Toughness Test Flattened Brazilian Disc (FBD) Mode

Mining activities in open pit and underground mines will always be associated with rock breaking or stripping activities (both mechanical and blasting), so that this can affect the structure and strength of rocks. The strength of the rock is strongly influenced by the presence of initial cracks (pre-existing cracks) and rock anisotropy conditions associated with discontinuous plane conditions. Fracture mechanics is a science that illustrates how a fracture can occur and propagate during applied stress on material. The main parameter in fracture mechanics is called fracture toughness which shows the resistance of the material to propagate the crack. There are several mode in determining type I fracture toughness, one of which is type I fracture toughness Flattened Brazilian Disc (FBD) mode. Type I fracture toughness test is carried out using a compression machine in a laboratory and is conducted on concrete samples consisting of 3 (three) various samples, with a ratio of cement and sand composition of 1:1, 1:2, and 2:1. This test also uses different loading rate values, namely 2.50 mm/min, 2.70 mm/min, and 2.83 mm/min. The results of the type I fracture toughness value from each loading rate will be compared to determine the effect of the loading rate on the value of type I fracture toughness. The obtained fracture toughness value is also related to the physical and mechanical properties of the samples. Based on the results of tests, it can be seen that the loading rate affects the value of fracture toughness, the increase in fracture toughness value is followed by the higher loading rate. In addition, it can be seen that the fracture toughness value is directly proportional to the uniaxial compressive strength value and the indirect tensile strength value. The average correlation value obtained is R2 = 0.9884 (indicating a strong relationship).

The Structuring and Empowerment Policy of Losari Beach Street Vendors Based on The Concept of Smart City

Mining activities in open pit and underground mines will always be associated with rock breaking or stripping activities (both mechanical and blasting), so that this can affect the structure and strength of rocks. The strength of the rock is strongly influenced by the presence of initial cracks (pre-existing cracks) and rock anisotropy conditions associated with discontinuous plane conditions. Fracture mechanics is a science that illustrates how a fracture can occur and propagate during applied stress on material. The main parameter in fracture mechanics is called fracture toughness which shows the resistance of the material to propagate the crack. There are several mode in determining type I fracture toughness, one of which is type I fracture toughness Flattened Brazilian Disc (FBD) mode. Type I fracture toughness test is carried out using a compression machine in a laboratory and is conducted on concrete samples consisting of 3 (three) various samples, with a ratio of cement and sand composition of 1:1, 1:2, and 2:1. This test also uses different loading rate values, namely 2.50 mm/min, 2.70 mm/min, and 2.83 mm/min. The results of the type I fracture toughness value from each loading rate will be compared to determine the effect of the loading rate on the value of type I fracture toughness. The obtained fracture toughness value is also related to the physical and mechanical properties of the samples. Based on the results of tests, it can be seen that the loading rate affects the value of fracture toughness, the increase in fracture toughness value is followed by the higher loading rate. In addition, it can be seen that the fracture toughness value is directly proportional to the uniaxial compressive strength value and the indirect tensile strength value. The average correlation value obtained is R2 = 0.9884 (indicating a strong relationship).

Design of Groundwater Sustain Irrigation Network System in Panca Lautang Area, Sidrap Regency, South Sulawesi

Mining activities in open pit and underground mines will always be associated with rock breaking or stripping activities (both mechanical and blasting), so that this can affect the structure and strength of rocks. The strength of the rock is strongly influenced by the presence of initial cracks (pre-existing cracks) and rock anisotropy conditions associated with discontinuous plane conditions. Fracture mechanics is a science that illustrates how a fracture can occur and propagate during applied stress on material. The main parameter in fracture mechanics is called fracture toughness which shows the resistance of the material to propagate the crack. There are several mode in determining type I fracture toughness, one of which is type I fracture toughness Flattened Brazilian Disc (FBD) mode. Type I fracture toughness test is carried out using a compression machine in a laboratory and is conducted on concrete samples consisting of 3 (three) various samples, with a ratio of cement and sand composition of 1:1, 1:2, and 2:1. This test also uses different loading rate values, namely 2.50 mm/min, 2.70 mm/min, and 2.83 mm/min. The results of the type I fracture toughness value from each loading rate will be compared to determine the effect of the loading rate on the value of type I fracture toughness. The obtained fracture toughness value is also related to the physical and mechanical properties of the samples. Based on the results of tests, it can be seen that the loading rate affects the value of fracture toughness, the increase in fracture toughness value is followed by the higher loading rate. In addition, it can be seen that the fracture toughness value is directly proportional to the uniaxial compressive strength value and the indirect tensile strength value. The average correlation value obtained is R2 = 0.9884 (indicating a strong relationship).

Ultrahigh-Q system of a few coaxial disks

Abstract Resonant modes of high contrast dielectric disk have finite Q-factors in the subwavelength range due to radiation leakage into the surrounding space. That leakage can be reduced considerably (a few times) by exploiting of the mechanism of destructive interference of two modes for avoided crossing of resonances (ACR) (Rybin et al. M. V. Rybin, K. L. Koshelev, Z. F. Sadrieva, et al., “High-Q Supercavity Modes in Subwavelength Dielectric Resonators,” Phys. Rev. Lett., vol. 119, p. 243901, 2017.). In the present paper we report suppression of radiation leakage by a few orders in magnitude via the ACR in the structure of three and four different coaxial disks. For fine multi-scale tuning of disks we reveal the ultrahigh-Q resonances of order 105 for the case of three disks and of order 106 for the case of four coaxial disks of equal radii.

Study on the Coupled Vibration Characteristics of a Two-Stage Bladed Disk Rotor System

This paper conducts a coupled vibration analysis of a two-stage bladed disk rotor system. According to the finite element method, the bladed disk rotor system is established. The substructure modal synthesis super-element method (SMSM) with a fixed interface and free interface is presented to obtain the vibration behaviors of the rotor system. Then, the free vibration results are compared with the ones calculated by the cyclic symmetry analysis method to validate the analysis in this paper. The results show that the modes of the two-stage bladed disk not only include the modes of the first- and second-stage bladed disk, but also the coupled modes of the two-stage bladed disk.

Non-linear dynamics of hydrodynamic tori as a model of oscillations and bending waves in astrophysical discs

ABSTRACT Understanding oscillations and waves in astrophysical fluid bodies helps to elucidate their observed variability and the underlying physical mechanisms. Indeed, global oscillations and bending modes of accretion discs or tori may be relevant to quasi-periodicity and warped structures around compact objects. While most studies rely on linear theory, observationally significant, non-linear dynamics is still poorly understood, especially in Keplerian discs for which resonances typically demand a separate treatment. In this work, we introduce a novel analytical model which exactly solves the ideal, compressible fluid equations for a non-self-gravitating elliptical cylinder within a local shearing sheet. The aspect ratio of the ring is an adjustable parameter, allowing a continuum of models ranging from a torus of circular cross-section to a thin ring. We restrict attention to flow fields which are a linear function of the coordinates, capturing the lowest order global motions and reducing the dynamics to a set of coupled ordinary differential equations (ODEs). This system acts as a framework for exploring a rich range of hydrodynamic phenomena in both the large amplitude and Keplerian regimes. We demonstrate the connection between tilting tori and warped discs within this model, showing that the linear modes of the ring correspond to oppositely precessing global bending modes. These are further confirmed within a numerical grid based simulation. Crucially, the ODE system developed here allows for a more tractable investigation of non-linear dynamics. This will be demonstrated in a subsequent paper which evidences mode coupling between warping and vertical motions in thin tilted rings.

Thermal barrier coating using yttria stabilized zirconia by plasma spray technique

This paper deals with the tribological behavior of thermal barrier coating in engine liner and it also deals with the quality of thermally treated coating. Multi-layer structure formed from top coat and bond coat which was deposited on the same type of steel substrates, in which heat treatments may improve the mechanical properties of materials both substrate and coating and enhance their hard-ness for many cases of ceramics through recrystallization of microstructures. In addition, heat treatments will introduce residual stresses by different thermal contractions and lattice misfits because of microstructural changes that could lead to either premature failure or stress relaxation by new crack formations. Tribological wear properties of differently treated thermal barrier coating was examined to see the net effect of heat treatment on mechanical properties by tribometer with pin on disc mode. Indentation test at surface and cross-section of coatings are examined. The SEM and optical microscope examine several crack propagations. Energy-dispersive X-ray spectroscopyhelps to characterize thermal barrier coating. After thermally treating the sample, an examination of thermal barrier coating the oxide content was increased, sample became convex due to residual compressive stress, roughness reduces, adhesion between topcoat, and bond coat get reduced eventually. In addition to that, the surface gets cracks due to the reduction in hardness from 330 HV to 212 HV.

Structural Strength and Reliability Analysis of Important Parts of Marine Diesel Engine Turbocharger

Supercharging is the main method to improve the output power of marine diesel engines. Nowadays, most marine diesel engines use turbocharging technology, which increases the air pressure and density into the cylinder and the amount of fuel injected correspondingly so as to achieve the purpose of improving the power. In a marine diesel engine, the turbocharger has become an indispensable part. The performance of turbochargers in a harsh working environment of high temperature and high pressure for a long time will directly affect the performance of diesel engine. Based on the market feedback data from manufacturers, the failure modes of compressor impeller, turbine blade, and turbine disk of marine diesel turbocharger are analyzed, and the statistical model of random factors is established. Using DOE design, the structural strength simulation data of 46 compressors and 62 turbines are obtained, and the response surface model is constructed. On this basis, Monte Carlo sampling is carried out to analyze the reliability of the compressor and turbine. The reliability of the compressor is good, while that of the turbine disk is 0.943 and that of the turbine blade is 0.96, which still has the potential of reliability optimization space. Therefore, a multiobjective optimization method based on the NSGA-II genetic algorithm is proposed to obtain the multiobjective optimization scheme data with the reliability and processing cost of turbine disk and blade as the objective function. After optimization, the reliability of turbine disk and blade is 1, the stress value of turbine blade is optimized by 4.7941%, the stress value of turbine disk is optimized by 3.0136%, the machining cost of the turbine blade is reduced by 15.5087%, and the machining cost of turbine disk is reduced by 3.9907%. At the same time, it is verified by simulation, the data based on NSGA-II multiobjective genetic algorithm are more accurate and have practical engineering reference value. The optimized data based on NSGA-II multiobjective genetic algorithm are used to manufacture new turbine samples, and the accelerated test of simulation samples is carried out. The cycle life of the optimized turbine can reach 101,697 cycles and 118,687 cycles, which is 51.75% and 77.11% longer than that of the unoptimized turbine. It can be seen that the optimized turbine can meet the requirements of the reliability index while reducing the manufacturing cost.

Eccentric disks falling in water

The freely falling of solid bodies in viscous liquids is an interesting issue concerned with many hydrodynamics and engineering problems. The eccentricity of the solid bodies may lead to new dynamic behaviors and complex paths of falling. Eccentric annular disks with holes covered by transparent tapes are used to study the effect of eccentricity on the descent flight. This paper experimentally investigates the falling regimes of the eccentric disks in water with Reynolds number between 4000 and 21 000 and classifies the descent modes into three types, i.e., the fluttering, chaotic, and tumbling motions, the transition motion, and the new stable descending motion. Finally, we map out the three descent modes of eccentric disks in a two-dimensional phase space of eccentricity e and dimensionless moment of inertia I*. It is found that eccentricity is a significant parameter when describing the descent modes of eccentric disks. Enough large eccentricity stabilizes freely falling disks, while small eccentricity (e < 0.06) leads to the rotation of disk in an arc in the x-y plane accompanied by chaotic and tumbling motions or asymmetric zigzag motion. The descent modes are mainly dependent on e for I* higher than 0.02, and dependent on both e and I* for I* lower than 0.02.

Mie Resonance Engineering in Two Disks

Recently the recipes to achieve the high-Q subwavelength resonances in an isolated dielectric disk have been reported based on avoided crossing (anticrossing) of the TE resonances under variation of the aspect ratio of the disk. In a silicon disk that recipe gives an enhancement of the Q factor by one order of magnitude. In the present paper we present the approach based on engineering of the spherical Mie resonances with high orbital index in two coaxial disks by two-fold avoided crossing of the resonant modes of the disks. At the first step we select the resonant modes of single disk which are degenerate because of the opposite symmetry. Approaching of the second disk removes this degeneracy because of interaction between the disks. As a result at certain distances we realize the hybridized anti-bonding resonant modes whose morphology becomes close to the spherical Mie resonant mode with high orbital index. Respectively the Q factor of the anti-bonding resonant mode can be enhanced by three orders of magnitude compared to the case of single disk.

Thermoelastic Characteristics of Functionally Graded Circular Disk Models under the Loading of Contact Forces

A rotating functionally graded circular disk undergoing a contact load is taken into account to investigate the thermoelastic characteristics. By considering contact force, a pair of partial differential equations is induced as the governing equations based on Hooke’s law. The behavior of circular disk modes is described with the variations of contact force and homogeneous thickness. A finite volume model is introduced to obtain approximate solutions for the governing equations because of the complexity of the equations. Contact force is highly influential in the radial direction compared to the circumferential direction in the displacement distribution, while a large radial stress appears near the area of the contact point. In the strain distribution, the magnitude increases as the angle grows near part of the outer boundary in the circular domain. The radial distribution profiles are susceptible to the growth of contact force in nearby area of the outer boundary, whereas the influences on the circumferential direction profiles are trivial. The increase of homogeneous thickness dwindles the radial magnitude of displacement, stress, and strain distribution profiles over nearby area of the outer boundary of the circular domain. As a result, numerical approach demonstrates that contact force and homogeneous thickness are indispensable parameters and provide deep influence on the thermoelastic movements of a rotating circular disk. Thus, the results obtained may be useful to design an appropriate FGM circular disk model for the industrial area by controlling the above parameters.