Stability Of Rod Research Articles

Synthesis and spectroscopic characterization of coumarin 440 dye doped silica gel rods

We have studied silica gel by sol–gel technique for the preparation of new dye-laser materials. Silica gel rods with dimension 50×10mm2 have been prepared successfully without breaking. It shows high transparency and good mechanical strength. Tetraethylorthosilicate (TEOS), formamide in molar ratio (0.25:0.70), 80ml ethanol, 20ml dimethylformamide (DMF), 10ml water, hydrochloric acid as a catalyst (at pH 6), and 0.5ml silicone defoaming agent/surfactant have been used. The synthesis has been carried out in a beaker and the reaction mixture is caste in to the flat bottom glass tubes at 40°C after thoroughly mixing of all the ingredients. These complex reactions, that carried out by hydrolysis and condensation in the silica gel formation show less gel time ∼8–10h at 40°C. Coumarin. 440 dye was doped during the preparation of all the ingredients solution mixture. It has been observed that that the compatibility of Nile blue dyes with silica-gel promise good homogeneity with transparency.In the present study, synthesis, dye doping, FTIR, UV–vis/NIR, and fluorescence have been studied. We have observed that coumarin doped silica gel rods give good fluorescence showing sharp peaks in the visible range. UV–vis spectra of prepared silica gel also indicate the absorption in visible range. Thermal stability of rods were studied by DSC/TGA methods. Eventually it is found that these dye doped silica gel materials explore the possibility for new solid-state dye laser materials.

Incorporation of silver-loaded ZnO rods into electrospun nylon-6 spider-web-like nanofibrous mat using hydrothermal process

Silver-doped zinc oxide rods were incorporated in a nylon-6 electrospun mat by a facile hydrothermal process. The rods exhibited excellent characteristics as a durable filter media with good antibacterial properties. ZnO nano-seeds blended with a nylon-6 solution were typically able to form ZnO-NPs-embedded spider-web-like nanonets during electrospinning. The simultaneous crystal growth of Ag NPs and ZnO rods from their precursor solutions on the surface of as-fabricated electrospun ZnO/nylon-6 fibers was carried out via a hydrothermal process. FE-SEM, TEM, UV–visible spectra, and photoluminescence spectra not only confirmed the formation of ZnO-nano-seeds-loaded electrospun nylon-6 composite fibers but also showed that ZnO rods doped with Ag NPs (approximately 50nm in size) were grown on the surface of the nylon-6 composite fibers during hydrothermal treatment. The antibacterial properties of different mats were tested against Escherichia coli. The as-synthesized Ag-NP-loaded nanocomposite revealed better antibacterial properties than those of composite mat without Ag NPs. The excellent stability of Ag-loaded ZnO rods (caused by ZnO nano-seeds) on the surface of electrospun fibers provides a new dimension in the fabrication of inorganic/organic nanocomposite.

Continuation of equilibria and stability of slender elastic rods using an asymptotic numerical method

We present a theoretical and numerical framework to compute bifurcations of equilibria and stability of slender elastic rods. The 3D kinematics of the rod is treated in a geometrically exact way by parameterizing the position of the centerline and making use of quaternions to represent the orientation of the material frame. The equilibrium equations and the stability of their solutions are derived from the mechanical energy which takes into account the contributions due to internal moments (bending and twist), external forces and torques. Our use of quaternions allows for the equilibrium equations to be written in a quadratic form and solved efficiently with an asymptotic numerical continuation method. This finite element perturbation method gives interactive access to semi-analytical equilibrium branches, in contrast with the individual solution points obtained from classical minimization or predictor–corrector techniques. By way of example, we apply our numerics to address the specific problem of a naturally curved and heavy rod under extreme twisting and perform a detailed comparison against our own precision model experiments of this system. Excellent quantitative agreement is found between experiments and simulations for the underlying 3D buckling instabilities and the characterization of the resulting complex configurations. We believe that our framework is a powerful alternative to other methods for the computation of nonlinear equilibrium 3D shapes of rods in practical scenarios.

Synthesis and spectroscopic characterization of Nile Blue doped silica gel rods

We have studied silica-gel by sol–gel technique for the preparation of new dye-laser materials. Silica gel rods with dimension 50mm×10mm have been prepared successfully without breaking. It shows high transparency and good mechanical strength. Tetraethylorthosilicate (TEOS), formamide in molar ratio (0.25:0.70), 80ml ethanol, 20ml dimethylformamide (DMF), 10ml water, hydrochloric acid as a catalyst (at pH 6) and 0.5ml silicone defoaming agent/surfactant have been used. The synthesis has been carried out in a beaker and the reaction mixture is caste in to the flat bottom glass tubes at 40°C after thoroughly mixing of all the ingredients. These complex reactions, that carried out by hydrolysis and condensation in the silica gel formation show less gel time ∼8–10h at 40°C. The doping of dye (Nile Blue 690) has been taken during the preparation of all the ingredients solution mixture. It has been observed that the compatibility of Nile Blue dye with silica-gel promise good homogeneity with transparency.In the present study, synthesis, dye doping, FTIR, UV/vis–NIR and fluorescence spectroscopy have been studied. We have observed that Nile Blue doped silica gel rods material give good fluorescence showing sharp peaks in the visible range. UV–vis spectra of prepared silica gel material also indicate the absorption in visible range. Thermal stability of rods was studied by DSC/TGA methods. Eventually it is found that these dye doped silica gel materials explore the possibility for new solid-state dye laser materials.

Stability of the drill-rod of modern machines for drilling of iron notch

The article considers the stability of a drill rod of a machine for drilling of the blast furnace iron notch. A technique for determination of the critical effort for the drill-rod was developed, taking into account the applied torque, and the angular velocity of the instrument. The suggested approach is simple to use and provide reasonable accuracy in the calculation of the allowable pressure of the drill-rod from the side of the mechanism for moving the carriage of a machine. The article presents a graph of the critical effort for the drill-rod on the depth of penetration of drilling tools in the iron notch. Obtained dependences allow picking up the geometric characteristics of the drill-rod, holding the drill bit, at the design stage of modern machine for drilling of iron notch. The materials of the article can be used by design engineers of metallurgical equipment and students.

ЭНЕРГЕТИЧЕСКИЙ МЕТОД ПРИ РАСЧЕТЕ НА УСТОЙЧИВОСТЬ СЖАТЫХ СТЕРЖНЕЙ С УЧЕТОМ ПОЛЗУЧЕСТИ

The problem of stability of polymer rods with account for creeping was resolved using the energy method customized by Tymoshenko and Ritz. Possible patterns of displacements were provided in the form of trigonometric series with undetermined coefficients. The principle of the minimal total potential energy of the system was taken as the basis. According to this principle, the form in which the potential energy has a minimum value is implemented in all possible patterns of deformation occurring due to the loss of stability. The energy method makes it possible to replace the solution of complex differential equations by the solution of simple linear algebraic equations. The result was obtained numerically using MatLab software applicable to different equations describing deformations and stresses caused by the exposure to creeping. The problem was solved for low and high density polyethylene. The equation of Maxwell and Thompson was employed in first case, and the equation of Maxwell and Gurevich — in the second one. The necessity of taking account of a “minor” component of elastic deformations using the Maxwell — Gurevich equation was proved.

The use of Markov chain theory in the problem of the dynamic stability of an elastic rod

The stability of the vertical position of an elastic rods, hinged at the ends and loaded at the upper end with a time-dependent longitudinal force containing a stochastic component, is considered. A homogeneous Markov chain is used to model the stochastic component. An inequality is obtained that depends on the characteristics of the stochastic force and the damping factor of the bar and, depending on whether this inequality is satisfied, the above equilibrium position will either be attracting or unstable.

Hydrothermal growth of mop-brush-shaped ZnO rods on the surface of electrospun nylon-6 nanofibers

This study is focused on forming a spider-wave-like nano-nets of nylon-6 decorated with unique mop-brush-shaped ZnO rods. The nanocomposite is prepared in two steps. First, ZnO nano-seeds containing electrospun nylon-6 nano-nets were fabricated by blending ZnO nanoparticles with nylon-6 solution. Second, the electrospun ZnO/nylon-6 composite was hydrothermalized with ZnO precursor solution to grow long ZnO mop-brush-shaped rods on the surface of fibers. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and FT-IR revealed that simultaneous formation of spider-wave-like nano-nets and effective uploading of ZnO nano-seeds were carried out by electrospinning from the blend solution. Field-scanning electron microscopy (FE-SEM) showed that unique mop-brush-shaped ZnO rods were effectively grown on the surface of nylon-6 fibers. As-synthesized spider-wave-like nano-nets of nylon-6 decorated with large number of mop-brush-shaped ZnO rods showed good hydrophilicity, photocatalytic property, and UV-shielding property. Furthermore, uploading technique of nano-seeds with small amounts during electrospinning and successive grown of sufficient amount of mop-brush-shaped ZnO rods nucleated by these nano-seeds during hydrothermal treatment provide a good stability of ZnO rods on the surface of fibers. Therefore, as-synthesized inorganic/organic nanocomposite (IONC) fibers may be used as potential textile for water treatment and protective clothing.

Characterization of Myosin Subfragment‐1 of Summer and Winter Silver Carp (Hypophthalmichthys molitrix) Muscle

Myosin subfragment-1 (S1) was prepared from myofibrils of summer and winter silver carp by chymotryptic digestion in the presence of ethylenediaminetetraacetic acid (EDTA). Two S1 heavy chain isoforms with different molecular sizes of 91 kDa and 95 kDa were detected in the fast skeletal muscle from summer and winter silver carp, respectively. ATPase inactivation assay indicated that winter S1 was about 20-fold unstable comparing to summer S1. Matrix-assisted laser desorption/ionization time-of-flight/mass spectrometry (MALDI-TOF MS) further confirmed that summer and winter myosin S1 heavy chain isoforms were homologous to myosin high-temperature type and myosin low-temperature type S1 heavy chain, respectively. Moreover, both types of myosin S1 heavy chain isoforms were identified at the intermediate stage. The results indicated that myosin was expressed in a season-specific manner; different types of myosin isomer expressed in different seasons, showing different thermostabilities. Silver carp, Hypophthalmichthys molitrix, is one of the most abundant freshwater fish species in China. The structure thermal stability of myosin rod from silver carp was affected by season change. The gel-forming abilities of surimi prepared in different seasons were different. This study investigated the seasonal differences in structure thermal stability of myosin S1 which is vital for gel formation of myosin. The results of this study will aid understanding of the relationship between the structure and function of myosin, and effective production of surimi from freshwater fish species in different seasons.

Stability of titanium nickelide rods loaded in the mode of martensite inelasticity

The work discusses experimental studies of stability and load capacity of titanium nickelide rods in the case of their isothermal loading by compression at the temperature of the martensite state. The experimental data are compared with the solution of the stability problem obtained within in the framework of the model of non-linear deformation of alloys with shape memory given phase and structural transformations. It has been established that the best estimate for critical forces is provided by the solution described in the concept of “general additional structural transition.”

Shape memory materials as an object of solid state mechanics: Experimental study, constitutive relations, solution of boundary value problems

The paper reports on new results of experimental research and simulation of thermomechanical phenomena characteristic of shape memory alloys. Experimental data are presented on the absence of work hardening in strain accumulation attendant on direct martensite transformation in shape memory alloys, cross hardening involved in martensite inelasticity and associated with preliminary direct marten-site transformation, rheonomic properties of shape memory alloys and stability of titanium nickelide rods loaded in the mode of martensite inelasticity. Some of the basic peculiarities of the processes occurring in shape memory alloys at different structural levels are briefly reviewed. A model that takes into account the above peculiarities and describes nonlinear scleronomic deformation of shape memory alloys in phase and structural transformation is set forth. Simplest variants of description of rheonomic properties of shape memory alloys are proposed. Different classes of boundary value and initial-boundary value problems of thermomechanics for shape memory alloys are considered.

Stability Estimates for a Twisted Rod Under Terminal Loads: A Three-dimensional Study

The stability of an inextensible unshearable elastic rod with quadratic strain energy density subject to end loads is considered. We study the second variation of the corresponding rod-energy, making a distinction between in-plane and out-of-plane perturbations and isotropic and anisotropic cross-sections, respectively. In all cases, we demonstrate that the naturally straight state is a local energy minimizer in parameter regimes specified by material constants. These stability results are also accompanied by instability results in parameter regimes defined in terms of material constants.

Nonlinear spatial bending of shear-deformable curvilinear rods

A finite element is proposed for analyzing nonlinear deformation and stability of three-dimensional rods at arbitrarily large elastic displacements. Timoshenko’s model is used for taking transverse shear strains into account. The accuracy and convergence of numerical solutions are studied by an example of problems of nonlinear bending of curvilinear rods.

Buckling of fibers in fiber-reinforced composites

Elastic stability of fibers in fiber-reinforced composite materials subject to compressive loading is studied. The transversal buckling mode is considered, and two limiting cases, the dilute and non-dilute composites are analyzed. In the case of a non-dilute composite, the cylindrical model and the lubrication approximation are applied. The original problem is reduced to a problem of stability of a rod on elastic foundation. Through the solution of this problem a simple formula for the buckling load is obtained. In the case of a dilute composite, the solution of a problem of stability of a compressed rod in elastic plane is used. On the basis of the obtained solutions in two limiting cases the interpolation formulae are derived. These formulae describe buckling of fiber in the fiber-reinforced composite for any value of the fiber volume fraction. Comparison with known numerical and experimental results is carried out, and the sufficient accuracy of the derived formulae is demonstrated.

The Air Controlled Hydraulic System Design of 3201z-Type Dump Truck Lifting Mechanisms

3201Z-type dump truck is modification desiged by EQ3208GJ dump truck chassis which the technical performance parameters are known, and using a lifting mechanism of air controlled hydraulic system. By analyzing the composition and working principle of air controlled hydraulic system and referring to similar models, the design of the tank, the limiting mechanism and power taker are conducted. By calculating the main technical parameters, including in the performances of the hydraulic cylinder and the hydraulic pump, the dump truck's special oil cylinder HG-E180X780 and gear pump CBT-E563 are selected. By the stability of the piston rod, the system pressure and cars lifting time are checked, the reasonability and safty of the design can be proved.

The Air Controlled Hydraulic System Design of 3201z-Type Dump Truck Lifting Mechanisms

3201Z-type dump truck is modification desiged by EQ3208GJ dump truck chassis which the technical performance parameters are known, and using a lifting mechanism of air controlled hydraulic system. By analyzing the composition and working principle of air controlled hydraulic system and referring to similar models, the design of the tank, the limiting mechanism and power taker are conducted. By calculating the main technical parameters, including in the performances of the hydraulic cylinder and the hydraulic pump, the dump truck's special oil cylinder HG-E180X780 and gear pump CBT-E563 are selected. By the stability of the piston rod, the system pressure and cars lifting time are checked; the reasonability and safty of the design can be proved.

Synthesis and spectroscopic characterization of Kiton Red-620 dye doped silica gel rods

The work was carried out to achieve two different but interdependent objectives; one to synthesis a transparent silica matrix with enough strength and thermal stability, by sol–gel technique, to host an organic dye molecule without quenching its fluorescence and two to find the probability if the said material is suitable for the construction of solid state dye lasers. Crack-free transparent silica gel rods with good mechanical strength, thermal stability and dimensions were successfully synthesized by sol–gel techniques. The rods were doped with Kiton Red-620 dye in different concentration separately. Effect of various synthesis parameters like time, temperature and aging condition was extensively studied to obtain crack-free silica rods doped with dye. Optical properties of prepared rods were studied by FTIR, UV/VIS–NIR and fluorescence spectroscopy. It is observed that Kiton Red-620 dye doped silica gel rods show good fluorescence with sharp peaks in the visible range. Their UV–VIS spectrum indicates the absorption in visible range. Thermal stability of rods were studied by DSC/TGA methods. Eventually it is found that these dye doped silica gel materials explore the possibility for new solid-state dye laser materials.

Biomechanical Assessment of a PEEK Rod System for Semi-Rigid Fixation of Lumbar Fusion Constructs

The concept of semi-rigid fixation (SRF) has driven the development of spinal implants that utilize nonmetallic materials and novel rod geometries in an effort to promote fusion via a balance of stability, intra- and inter-level load sharing, and durability. The purpose of this study was to characterize the mechanical and biomechanical properties of a pedicle screw-based polyetheretherketone (PEEK) SRF system for the lumbar spine to compare its kinematic, structural, and durability performance profile against that of traditional lumbar fusion systems. Performance of the SRF system was characterized using a validated spectrum of experimental, computational, and in vitro testing. Finite element models were first used to optimize the size and shape of the polymeric rods and bound their performance parameters. Subsequently, benchtop tests determined the static and dynamic performance threshold of PEEK rods in relevant loading modes (flexion-extension (F/E), axial rotation (AR), and lateral bending (LB)). Numerical analyses evaluated the amount of anteroposterior column load sharing provided by both metallic and PEEK rods. Finally, a cadaveric spine simulator was used to determine the level of stability that PEEK rods provide. Under physiological loading conditions, a 6.35 mm nominal diameter oval PEEK rod construct unloads the bone-screw interface and increases anterior column load (approx. 75% anterior, 25% posterior) when compared to titanium (Ti) rod constructs. The PEEK construct's stiffness demonstrated a value lower than that of all the metallic rod systems, regardless of diameter or metallic composition (78% < 5.5 mm Ti; 66% < 4.5 mm Ti; 38% < 3.6 mm Ti). The endurance limit of the PEEK construct was comparable to that of clinically successful metallic rod systems (135N at 5 × 10(6) cycles). Compared to the intact state, cadaveric spines implanted with PEEK constructs demonstrated a significant reduction of range of motion in all three loading directions (> 80% reduction in F/E, p < 0.001; > 70% reduction in LB, p < 0.001; > 54% reduction in AR, p < 0.001). There was no statistically significant difference in the stability provided by the PEEK rods and titanium rods in any mode (p = 0.769 for F/E; p = 0.085 for LB; p = 0.633 for AR). The CD HORIZON(®) LEGACY(™) PEEK Rod System provided intervertebral stability comparable to currently marketed titanium lumbar fusion constructs. PEEK rods also more closely approximated the physiologic anteroposterior column load sharing compared to results with titanium rods. The durability, stability, strength, and biomechanical profile of PEEK rods were demonstrated and the potential advantages of SRF were highlighted.

Rod dynamics in a press-roller piercing mill

The production of hotrolled seamless pipe from continuouscast rectangular blanks may be based on press-roller piercing, which includes elements of press piercing and longitudinal rolling in round grooves. At present, the piperolling line at many foreign plants includes more than ten press-roller piercing mills, capable of producing pipe in the diameter range 150-410 mm. As a rule, the press-roller piercing mills produced in Ukraine and elsewhere consist of a tworoller longi� tudinalrolling mill with round grooves. In such mills, the rod with the mandrel is positioned on the rolling axis and is held there by means of special mechanisms in subsequent piercing operations. The blank is sup� plied to the working rollers by means of a hydraulic pushod unit, which steadily braces the blank by means of the necessary force, throughout the piercing cycle. The stress-strain state in the deformation source is such as to ensure favorable compressive stress and slight extension in the pierced metal (1). To ensure the required dynamic stability of the mandrel rod in the deformation source, we need to eliminate piercing conditions associated with high� amplitude parametric oscillation in the system. In the present work, we study rod vibration in the mechanism holding the mandrel at the axis of the press-roller piercing mill. The dynamic processes at the output side of the mill were studied theoretically and experimentally in (4, 5). The forces on the mandrel rod were analyzed, and possible conditions associated with transverse vibration in the mechanism holding the mandrel at the rolling axis were identified. This research focused on simplified dynamic models of the mandrel rod in pipe� rolling mills and did not adequately address techno� logical and operational aspects of press-roller pierc� ing, such as rod vibration in the mechanism holding the mandrel at the axis. In the present work, we investigate the appearance of transverse parametric vibration in the mandrel rod of the press-roller piercing mill. We take account of the nonsteady action of the deformation source and

Structural Stability of Myosin Rod from Silver Carp as Affected by Season

Chymotrypsin digestion and Circular dichroism (CD) spectroscopy were used to study the structural stability of myosin rods prepared from silver carp in summer and winter. Differences in the thermal stability were clearly demonstrated by the chymotryptic digestion patterns and CD data obtained at pH 7.5 in 0.5 M KCl for myosin rods in both seasons, indicating the structural properties differed seasonally. In winter, the myosin rods were more susceptible to be cleaved into short (40 kDa) subfragments when digested at high temperature (30 °C). The major peaks in unfolding profiles showed that transition temperatures for the rods were 35 °C in winter, and 36 and 41 °C in summer. Rod subfragments (S-2 and LMM) were isolated and further analyzed by CD. In both winter and summer, the LMM fragments showed an unfolding transition at around 35.5 °C, but the S-2 fragments showed large seasonal difference; in winter, they showed a major unfolding peak around 35 °C and a minor peak at 40.5 °C, while in summer, they unfolded mostly at 44.5 °C, which was 8 °C higher than that for the LMM fragments. Short (40 kDa) S-2 subfragments isolated from winter rods gave a single unfolding transition at 41 °C. These results suggest that differences in the thermal stability of myosin rods between winter and summer were due to differences in the stability of S-2 region. The aim of this study was to detect the differences in the structure thermal stability of myosin rods between summer and winter, which is a very important portion for gel formation. The information will be very useful for producing surimi from freshwater fish species in different seasons.