Rod Material Research Articles

КРУЧЕННЯ ЗІ ЗГИНОМ ТА РОЗТЯГОМ ПРУЖНО-ПЛАСТИЧНОГО СТЕРЖНЯ

Розглянуто задачу про визначення напружено-деформованого стану пружно-пластичного стержня сталого однозв’язного поперечного перерізу, який зазнає одночасного кручення, згину та розтягу. Задача розв’язується за допомогою напівзворотного методу, а також методу скінченних елементів. Для опису поведінки матеріалу стержня використовується теорія малих пружно-пластичних деформацій Генкі – Надаї – Ільюшина. Досліджено вплив параметрів навантаження на вигляд пластичних зон у перерізі стержня.

Effective parameters of a metamaterial composed of dielectric coated conducting cylindrical rods

AbstractIn the first part, the scattering characteristics of an isolated dielectric coated conducting rod have been investigated. The types of considered coatings for the scattering analysis are realistic materials including barium strontium titanate, magnetodielectric, gallium arsenide, and silicon carbide. It is found that the gallium arsenide coating can be used to significantly reduce the scattering from a thin perfectly electric conducting cylindrical rod at specific observation angles. In the second part, the effective permittivity and permeability of metamaterials composed of two dimensional periodic arrangements of these dielectric coated conducting cylindrical rods have been studied. An increase in the double negative (DNG) bandwidth of a metamaterial composed of barium strontium titanate coated conducting rods has been observed in contrast to the corresponding bandwidth of a metamaterial composed of only barium strontium titanate material rods. Also an additional plasmonic epsilon negative (ENG) bandwidth has been found in case of a metamaterial composed of barium strontium titanate coated conducting rods. It is further studied that the widest ENG, mu negative, and DNG bandwidths exist for a metamaterial composed of gallium arsenide rods.

Evaluation of a mass spectrometry and Vitek 2 combined protocol for rapid identification and susceptibility testing of Enterobacterales directly from positive blood cultures

ObjectiveThe aim was to evaluate a rapid method which would combine identification and susceptibility testing directly from positive blood cultures for Gram-negative bacilli of the Enterobacterales. Material and methodsGram-negative rods from blood cultures were directly identified by MALDI-TOF. Samples with Enterobacterales were selected for direct antimicrobial susceptibility testing by Vitek 2. The results were compared to those obtained with our laboratory's standard method. ResultsMALDI-TOF directly from blood cultures identified correctly 83% of the samples. Enterobacterales (n=68) were identified at gender and species level in 85% of blood cultures with a score >1.7. In general, MICs were obtained after 7h. MICs of amoxicillin-clavulanate, amikacin and ciprofloxacin showed in almost 50% of the cases after 5h. ConclusionsA simple procedure with low cost and reduced working time makes it possible to integrate both identification and susceptibility testing directly from blood cultures. Thus, this protocol could offer advantages when it comes to selection and cost of treatment and patients’ clinical outcomes.

Iron-based shape memory alloy and fiber reinforced polymers rods for prestressed NSM strengthening of RC beams

Abstract The present study involves flexural strengthening of reinforced concrete (RC) beams by prestressed fiber reinforced polymers (FRP) and iron-based shape memory alloys (Fe-SMAs) using the near surface mounted (NSM) technique. ANSYS nonlinear finite element analysis (FEA) software was employed to model RC beams which were validated using the data from an existing experimental study in the literature. Parameters considered were rod length and NSM rod material type under three prestressing levels 20, 30 and 40%. The influence of these parameters on the beams’ load carrying capacity, midspan displacement, ductility index, and failure mode were determined. The results showed that at higher levels of rod prestressing, cracking, yielding, and ultimate load capacities of the beam were improved. However, the displacement was decreased and consequently, the ductility index reduced as prestressing level increased. Furthermore, the Fe-SMA material was able to provide significant ductility. The optimum prestressing level could be identified based on the primary RC beams’ design criteria to either improve load or displacement capacity or both.

Effet de la taille de la boucle sur la sécurité du serrage et l’élongation d’un nœud en chirurgie de la coiffe des rotateurs

IntroductionWhile repairing a teared rotator cuff tendon with suture anchors and horizontal mattress suture configurations, knots should be secure at time zero while approximating the tendon to the bone, otherwise any failure in loop security may cause undesired clinical results. Optimum distance between suture limbs passed through the tendon, in other words the bite size, is still not clear in the literature. The aim of this study was to test the effect of loop size, which is directly related to the bite size, on loop security and elongation of a knot. HypothesisWe hypothesized that a knot with a smaller loop size would be more secure. We asked if a knot with shorter circumference (1) would offer a better knot security, (2) would produce less elongation following repeated traction cycles. Material and methodsTwo parallel metal rods in 3.0mm diameter were fixed to load cells of dynamic testing machine. Four groups, from A to D, had the initial rod to rod distances of 2–4–6–8mm respectively (n=10). Surgeon's knots were prepared with 2/0 Ultrabraid® sutures around the rods. A tension meter was used for tying each half hitch under equal tension. Crosshead distances were recorded after 7N pre-load and subsequent 1000 repetitive cyclic loads between 7-30N. ResultsElongations after a 7N preload for groups A to D were 0.107mm (±0.006), 0.143mm (±0.018), 0,16mm (±0.025), 0.185mm (±0.018) respectively. This increase was significant (p<.05, power>0.95) between each group except between groups B and C. Maximum elongations after 1000th cycle for groups A to D were 0.32mm (± 0.124), 1.12mm (±0.333), 1.162mm (±0.211), 1.292mm (±0.241) respectively. Only samples in group A (0.732mm±0.124) elongated significantly less than others (p<.05, power>0.95). No knots unravelled or ruptured. DiscussionThis study basically reports that a knot with a shorter loop circumference has superior properties regarding loop security and resistance to elongation. From the perspective of clinical importance, shorter distance between suture limbs of mattress configuration may provide a more secure fixation of the rotator cuff tendon to the bone. Level of evidenceII.

Multiple-rod constructs in adult spinal deformity surgery for pelvic-fixated long instrumentations: an integral matched cohort analysis.

Multiple-rod constructs (Multi-Rod: extra rods for additional pillar support) are occasionally used in adult spinal deformity (ASD) surgery. We aimed to compare and analyze the general outcome of multi-rod constructs with a matched two-rod cohort, to better understand the differences and the similitudes. This is a retrospective matched cohort study including patients with ASD that underwent surgical correction with long posterior instrumentation (more than five levels), pelvic fixation and a minimum 1-year follow-up. Matching was considered with demographical data, preoperative radiographical parameters, preoperative clinical status [health-related quality-of-life (HRQoL) scores] and surgical characteristics (anterior fusion, decompression, rod material, osteotomies). Postoperative radiographical and clinical parameters, as well as complications, were obtained. Univariate and multivariate analysis was performed regarding postoperative improvement, group variables comparison and parameters correlation. Thirty-three patients with multi-rod construct and 33 matched with a two-rod construct were selected from a database with 346 ASD-operated patients. Both groups had a significant improvement with surgical management in the radiographical and HRQoL parameters (p < 0.001). Differences between groups for the postoperative radiographical, clinical and perioperative parameters were not significant. Rod breakage was more frequent in the two-rod group (8 vs 4, p = 0.089), as well as the respective revision surgery for those cases (6 vs 1 p = 0.046). Risk factors related to revision surgery were greater kyphosis correction (p = 0.001), longer instrumentation (p = 0.037) and greater sagittal vertical axis correction (p = 0.049). No major disadvantage on the use of multi-rod construct was identified. This supports the benefit of using multi-rod constructs to avoid implant failure. These slides can be retrieved under Electronic Supplementary Material.

Conceptual design and uncertainty analysis of a typical 50 kW aqueous homogeneous reactor aimed for medical isotope production

Production of medical isotopes such as 99Mo, 90Sr, 131I and other fission products using Aqueous Homogeneous Reactors (AHRs) offers several advantages in comparison to other methods. In this method, after about one week operation, required isotopes can be directly extracted from the solution and the remaining fuel solution will be returned to the core for the next campaign. Moreover, AHRs are inherently safe and reliable due to their large negative reactivity feedbacks. This paper demonstrates technical features and conceptual scheme of the Iranian homogeneous reactor named RAHA, which is mainly used for the production of 99Mo/99mTc. Neutronic and thermal-hydraulic characteristics of the reactor were analyzed with MCNPX-2.6 and RELAP5/Mod3.3 codes, respectively. It was assumed that the reactor is fueled by Uranyl Nitrate, and is able to remove generated heat using natural circulation. The coolant circulation velocity was obtained as 6.5 cm/s. Four different types of neutron absorbers were considered as control rod material, and BORA resin with a diameter of 1.4 cm and Stainless-Steel cladding was chosen. As a new characteristic which may improve safety of the system, the possibility of reactor startup without any external neutron source for the case of fresh fueled core was assessed. Finally, effects of the possible uncertainties on some physical and material properties of the core were investigated and sensitivity of the effective multiplication factor relative to the uncertain parameters was also extracted using Spearman's formula.

Design, Analysis and Topology Optimization of a Connecting Rod for Single Cylinder 4–Stroke Petrol Engine

The aim of the study is to design, analyse and carry out a topology optimization of a connecting rod for single cylinder four stroke petrol engines. In order to obtain a 3D CAD model from existing physical connecting rod is developed through reverse engineering. A three dimensional CAD model of a connecting rod has been created using SOLIDWORKS and it is imported to ANSYS for the coupled steady-state thermal structural analysis, to verify the design of a connecting rod before and after weight reduction. For material optimization, three different aluminium alloy materials such as ADC12, LM6 and Al 6061–T6 alloy were used. From the results obtained from coupled steady-state thermal structural analysis and topology optimization, the optimized design of a connecting rod of Al 6061-T6 alloy shows the von-mises stress of 33.17 MPa, factor of safety 8.32 and total deformation 45.023 mm as compared to other two materials. Based on the topology optimization methodology, it is noted that Al 6061- T6 connecting rod material reduced the weight up to 7.98 % as compared with ADC12 without compromising the strength to weight ratio and ductility.

Motion analysis of lumbar vertebrae for different rod materials and flexible rod device – An experimental and finite element study

Different stabilization devices have been used for treating lumbar spine disorders, including fusion, dynamic stabilization devices, flexible rods etc., which possess a different level of limitations. A simple experimental procedure is developed using a prototype lumbar spine specimen (L1-S), to evaluate the biomechanical performance of the lumbar spine. The range of motions (ROM) are tested for pedicle screw made of stainless steel (SS) fixation, using Teflon rod, ultra high molecular weight poly ethylene (UHMWPE) rod, poly ether ether ketone (PEEK) rod and SS flexible rod device (FRD). SS pedicle screw is used for fixation on the prototype lumbar spine. Experimental results are validated and compared with finite element (FE) results. It is observed that, in both flexion and extension, reduction in ROM is higher for Teflon and UHMWPE as compared to PEEK and FRD system. Differences between experimental and numerical results are found to be within an acceptable limit of 5–11%. For flexibility study, both numerical and experimental results support that PEEK rod plays an effective and important role among all the semi-rigid rods. The FRD devices are found to preserve the flexibility of the segment considerably better than PEEK rod.

Torsion of anisotropic and inhomogeneous prismatic rods with a rectangular cross section

The limiting state of prismatic rods made of anisotropic material under torsion under the condition of translational plasticity is investigated. The rod of heterogeneous material is represented by a composite rod, when different plasticity conditions are true in different parts of the rod. Basic relations are determined by the method of characteristics. A field of characteristics of the basic relations for anisotropic and composite rods is constructed under the condition of translational plasticity, relations are obtained by characteristics, a tension break lines are found.

Fabrication of prototype connecting rod of PLA plastic material using FDM prototype technology

Rapid prototyping (RP) have been attracting attention in the manufacturing community because of their capability to reduce the lead time of product development. Present work is an effort to understand the influence of process variables like infill pattern, layer thickness, build orientation and infill density on dimensional accuracy (DA), flatness and cylindricity. Taguchi method orthogonal array L9 was used for the conduction of experiments. MakerBot Replicator-2 was used for the fabrication of scaled prototype connecting rod of polylactic acid (PLA) material. DA, flatness and cylindricity of the component were measured by using coordinate measuring machine (CMM). Analysis of variance (ANOVA) was employed to find out the significance of process parameters. A regression model was developed to predict the DA, flatness and cylindricity. The results reveal that the optimum process parameters for the DA, flatness and cylindricity were different. Utility Theory was used to find out the best process parameter condition. The best process parameters for the DA, flatness and cylindricity was found to be layer thickness 100 μm, linear infill pattern, inclined at 45ºorientation and 20% infill density. A confirmation test was conducted for checking the goodness of the model, which reveals that results were within the confidence limit.

Improvement of the working bodies of the harvesting machines by means of the use of composite materials

Potato production is associated with high energy and labor costs, and the final part (harvesting) accounts for the bulk of the costs. When designing potato harvesting technology, the main focus is on the separation of soil impurities, which make up about 97 % with a high yield of 300 kg/ha, and lower yields increase them to 98–99 %. Nowadays, with the advent of new materials and new technologies in agricultural engineering, there is modernization of existing structures using innovative materials, as a result of which some new and having no analogues models are created that can improve the quality of the machine, increase its service life, and reduce energy costs. The effectiveness of the working bodies of potato harvesters determines the ratio of the separating ability of the working body to its energy consumption. As a result of the studies, power parameters and the separating ability of the main working bodies were generalized. The modernization of the separating elevator consists in replacing the metal rods of an existing elevator apron with a similar apron with rods of some composite material. This modernization can significantly reduce the mass of the working body and the whole combine as a whole and reduce energy consumption.

Механические свойства и структура наплавок из титановых сплавов, легированных кислородом из оксидного слоя наплавочных прутков

Prospects of oxygen alloying of alloys in the process of cladding of rods on parts from titanium alloys aimed at raising their hardness are considered. Experiments on fabrication of samples of titanium alloys with remelting of the filler rods with oxide coating formed by plasma electrolytic oxidation are performed. The main mechanical characteristics of the clad rod material modified by introduction of oxygen from the oxide layer are determined and the structural features of the material are analyzed.

A Study on Factors Influencing the Accuracy Evaluation of Dimensional X-Ray Computed Tomography with Multi-sphere Standards

Industrial X-ray Computed Tomography (XCT) is one of the available choices for measuring parts’ internal and external geometries. However, there are still several challenges that limit the current XCT technologies from being widely spread as a dimensional metrology tool. In the study presented in this paper, multi-sphere standards were developed and used for the evaluation of the accuracy of dimensional measurements performed with an open-ended 450 kV XCT system of 0.4 mm focal spot. Normally, the multi-sphere standard refers to a combination of several ball rods of various heights, where a ‘ball rod’ is understood as a ruby sphere mounted on a rod that is usually made of carbon fiber or ceramic. The main purpose was to determine if the rod’s material, the spatial distribution of the ruby spheres, and/or the selection of test lengths (i.e., the center-to-center distance between two ruby spheres) influence the determination of the maximum permissible sphere distance error (MPESD) attributable to XCT data. The experimental data suggested ceramic is more suitable as a rod material than carbon fiber, and also, the spatial distribution of the ruby spheres has no obvious influence on the accuracy evaluation of dimensional measurements. However, the selection of test lengths will significantly affect the accuracy evaluation results. In particular, the results of dimensional measurements showed that the evaluation of the MPESD with multi-sphere standards for the XCT system used in this study can be expressed as MPESD = ± (159 + L/800) μm.

Neutronic feasibility of civil marine small modular reactor core using mixed [formula omitted] coolant

In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable that a civil marine core not to use highly enriched uranium, but it is then a challenge to achieve long core lifetime while maintaining reactivity control and acceptable power distributions in the core. The objective of this study is to design a civil marine core type of single batch small modular reactor (SMR) with low enriched uranium (LEU) (<20% 235U enrichment), a soluble-boron-free (SBF) and using mixed D2O+H2O coolant for operation period over a 20 years life at 333 MWth. Changing the coolant properties is the way to alter the neutron energy spectrum in order to achieve a self-sustaining core design of higher burnup. Two types of LEU fuels were used in this study: micro-heterogeneous ThO2-UO2 duplex fuel (18% 235U enriched) and all-UO2 fuel (15% 235U enriched). 2D Assembly designs are developed using WIMS and 3D whole-core model is developed using PANTHER code. The duplex option shows greater promise in the final burnable poison design with high thickness ZrB2 integral fuel burnable absorber (IFBA) while maintaining low, stable reactivity with minimal burnup penalty. For the final poison design with ZrB2, the duplex contributes ∼2.5% more initial reactivity suppression, although the all-UO2 design exhibits lower reactivity swing. Three types of candidate control rod materials: hafnium, boron carbide (B4C) and 80% silver + 15% indium + 5% cadmium (Ag-In-Cd) are examined and duplex fuel exhibits higher control rod worth with the candidate materials. B4C shows the greatest control reactivity worth for both the candidate fuels, providing ∼3% higher control rod worth for duplex fuel than all-UO2. Finally, 3D whole-core results from PANTHER show that the use of the mixed coolant contributes to ∼21.5 years core life, which is a ∼40% increase in core life compared to H2O coolant (∼15.5 years) while using the same fuel candidates and fissile enrichment. The mixed coolant provides excellent core lifetimes comparable to those of HEU military naval vessels (∼25 years vs. ∼21.5 years) while utilizing LEU candidate fuels.

Floating zone furnace equipped with a high power laser of 1 kW composed of five smart beams

A floating zone furnace is a powerful tool for single crystal growth. Here, we report the floating zone furnace using a high power diode laser of 1kW composed of five 200 Watt heating beams. The five beams with the designed irradiation intensity distribution enable the melt-growth of single crystals for refractory materials having a high melting temperature above 2000{\deg}C, volatile materials and even incongruent materials. The power of five beams in the horizontal plane provides uniform intensity in the outer circumference of the raw material rods, while the vertical direction power of five beams can be made to have a bell shape irradiation intensity so as to relax residual thermal stress in the grown single crystal. The present furnace enables one to directly monitor the temperature of the hot spot of raw material and the molten zone within a 1 mm diameter. Such an in-situ monitoring function of the temperature on the molten zone greatly enhances the controllability for optimizing the crystal growth condition.

Desain Konstruksi Press Tool Sebagai Alat Bending Bentuk V Dengan Garis Bending Max. 300mm

Nowadays, the process of metal forming in the machining industry and welding workshop is developing very rapidly especially in the plate bending process. The bending process is the formation of metals which generally use plates or rods of both ferrous and non-ferrous metal materials by bending, which in the bending process will cause stretching or stretching on the neutral plane axis along the bending area and produce a straight bend line. The use of appropriate technology machines has been widely used to increase productivity, efficiency, and effectiveness in the production process for community businesses, especially those in the regions. One of the appropriate technologies that might be applied in the bending process is a hydraulic jack press that is equipped with a press tool. Press tool is one type of product forming, cutting and bending tools from the basic material of sheet plates whose operations are using a press tool. The results of the design of press tool bending tool V have a length of 300 mm bending line, 33 mm bending width, 110 mm spring height, free step distance of 19 mm. The punch angle used is 85⁰ with the punch radius used is 1.5 mm while the die angle is 85⁰. The selected punch and die material is Steel AISI 1045 HV HR.

Dependence of Creep-Rupture Lifetime for Rods under Tension in an Aggressive Environment on the Shape of a Single-Cell Cross-Section

The long-term strength of rods under tension in an aggressive environment is investigated. We consider rods of various shapes of a single-cell cross-section (circle, square, and rectangles with different aspect ratios), provided that the areas of these cross-sections are equal. To determine the level of inclusions from aggressive environment into the rod at different time moments, approximate diffusion equations based on the motion of diffusion fronts from the rod surface are used. The high accuracy of the obtained approximation is shown. To assess the influence of an aggressive environment on long-term strength, the Yu. N. Rabotnov kinetic theory with two structural parameters (material damage and concentration of environment elements in the rod material) is used. The dependence of the time to rupture for the rods with various cross-section shapes under the same level of tensile stress is obtained. It is shown that the time to rupture for a rod with square cross-section under the indicated conditions exceeds the time to rupture for a rod with circular cross-section. In the case of rods with the same cross-section shape, the relation of the cross-section perimeter to time to rupture for the rod is considered. The minimum time to rupture for the considered rods is observed for rods of rectangular cross-section with the smallest thickness

Influences of Diamond Material on Heat Dissipation Capabilities of Helical Slow Wave Structures

From theoretical calculations, simulations, and emulations, as well as laboratory testing, we evaluated the influences of both diamond and diamond-film-coated support rods, as well as diamond-film-coated helices, on the heat dissipation capabilities of slow wave structures (SWSs). A comparison between the experiment and simulation data shows that the computer simulation results are in good agreement and offer an important reference for the application of diamond in SWSs. An expression for the coefficient of thermal conductivity for the helix material and for the support rod material indicates that the greater their value, the better the heat dissipation capability of the helical SWS. The simulation and emulation analysis results show that when the helix reaches the same temperature, SWSs made of diamond-film-coated support rods and helix are able to consume 20%-60% more heating power than normal SWSs. Similar to a purely diamond support rod, a diamond-film-coated helix and support rod are able to improve the heat dissipation capabilities of SWSs effectively. In experiments, we tested the heat dissipation capabilities of SWSs with their helix surfaces plated with high-performance gold/copper films and BeO/BeN support rods. The experimental results agree well with the ANSYS simulation and emulation results.

The effect of loop size on loop security and elongation of a knot

IntroductionWhile repairing a teared rotator cuff tendon with suture anchors and horizontal mattress suture configurations, knots should be secure at time zero while approximating the tendon to the bone, otherwise any failure in loop security may cause undesired clinical results. Optimum distance between suture limbs passed through the tendon, in other words the bite size, is still not clear in the literature. The aim of this study was to test the effect of loop size, which is directly related to the bite size, on loop security and elongation of a knot. HypothesisWe hypothesized that a knot with a smaller loop size would be more secure. We asked if a knot with shorter circumference (1) would offer a better knot security; (2) would produce less elongation following repeated traction cycles. Material and methodsTwo parallel metal rods in 3.0mm diameter were fixed to load cells of dynamic testing machine. Four groups, from A to D, had the initial rod to rod distances of 2-4-6-8mm respectively (n=10). Surgeon's knots were prepared with 2/0 Ultrabraid® sutures around the rods. A tension meter was used for tying each half hitch under equal tension. Crosshead distances were recorded after 7N pre-load and subsequent 1000 repetitive cyclic loads between 7-30N. ResultsElongations after a 7N preload for groups A to D were 0.107mm (±0.006), 0.143mm (±0.018), 0,16mm (±0.025), 0.185mm (±0.018) respectively. This increase was significant (p<0.05, power>0.95) between each group except between groups B and C. Maximum elongations after 1000th cycle for groups A to D were 0.32mm (±0.124), 1.12mm (±0.333), 1.162mm (±0.211), 1.292mm (±0.241) respectively. Only samples in group A (0.732mm±0.124) elongated significantly less than others (p<0.05, power >0.95). No knots unravelled or ruptured. DiscussionThis study basically reports that a knot with a shorter loop circumference has superior properties regarding loop security and resistance to elongation. From the perspective of clinical importance, shorter distance between suture limbs of mattress configuration may provide a more secure fixation of the rotator cuff tendon to the bone. Level of evidenceII.