Bar Material Research Articles

Exploring the Physicochemical and Sensory Characteristics of Snack Bars Utilizing Arrowroot (Marantha arundinacea) Flour and Brown Rice Flour

Abstract Arrowroot is rich in carbohydrates, making it an excellent source of energy. It is also gluten-free, making it accessible to individuals with celiac disease or gluten intolerance, thereby contributing to more inclusive food security. Arrowroot flour and brown rice have potential as raw materials for high-fiber snack bars. This study aimed to assess how varying proportions of arrowroot flour and brown rice affect the physicochemical and organoleptic characteristics of these snack bars. Employing a Completely Randomized Design, different ratios of arrowroot flour to brown rice (100%:0% (F1); 75%:25% (F2); 50%:50% (F3); 25%:75% (F4); and 0%:100% (F5)) were tested. The snack bars underwent analysis for physicochemical attributes such as water and ash content, fat, total protein, carbohydrates, total sugar, and hardness. Organoleptic evaluations, encompassing hedonic testing and scoring by 25 untrained panelists, were conducted based on parameters including color, taste, aroma, texture, aftertaste, hardness, brittleness, and stickiness. Results indicated significant impacts of the arrowroot flour and brown rice formulations on both physicochemical (e.g., water content, ash, fat, total protein, carbohydrates, calories, total sugar, and hardness) and organoleptic properties (e.g., color, taste, aroma, texture, aftertaste, hardness, brittleness, and stickiness) of the snack bars. The formulation with a 25%:75% ratio (F4) yielded the highest fiber content, reaching 12.46%.

Electropolishing study of metastable austenitic steel AISI 347 for EBSD analyses

Abstract For the metastable austenitic steel AISI 347 (X6CrNiNb18-10), various electropolishing parameters were evaluated by means of hardness testing, electron backscatter diffraction (EBSD), and atomic force microscopy. Depending on the chosen parameters, different surface characteristics could be achieved simply by only varying voltage, flow rate, and polishing time, although EBSD indexing was always possible. Differences in hardness of up to 20 HV0.5 and in microscopic roughness could be detected on otherwise comparable samples. Finally, the microstructure distribution of a hot rolled bar material with a diameter of 153 mm made from AISI 347 was characterized over the cross section using the previously determined parameter set. Here, insights about recrystallization during forming were concluded and δ-ferrite was differentiated from α’-martensite by kernel average misorientation and morphology.

Retention and wear assessment of two different bar materials used in implant-retained mandibular overdenture

Abstract Aim To assess retention and wear of two different bar materials (cobalt chromium and poly ether-ether ketone) used in implant-retained mandibular overdenture subjected to chewing simulation Robota during 1 year of functional simulation. Patients and methods This study is a comparative laboratory study which was carried out on 14 models of implant-retained mandibular overdenture, for each model two implants were inserted. The 14 models were divided equally into two equal groups: group A (overdenture constructed over two implant analogs with bar attachment and clip made from cobalt chromium material), and group B (overdenture constructed over two implant analogs with bar attachment and clip made from poly ether-ether ketone material). Drilling of the models was done using milling machine and each model received two implant analogs inserted 11 mm from midline at canine region. The overdentures were constructed in the usual manners and the teeth were set in lingualized occlusion. The mandibular overdentures were subjected to 150 000 chewing cycles using Robota chewing simulator and 1080 insertion-removal cycles. Retention of the samples was measured by the universal testing machine and wear observed under USB digital microscope both of which were done at the beginning of the study and after 3, 6, 9, and 12 months. Results The retention force for group A decreased significantly from baseline 43.43 ± 5.25 to 35.56 ± 8.30 after 3 months of cyclic loading, with similar reductions after 6, 9, and 12 months. Group B also showed reductions from baseline 26.75 ± 2.32 to 21.29 ± 6.74 after 3 months, and similar patterns over time. Group A had no statistically significant wear changes after cyclic loading, with a baseline mean of 0.2904 ± 0.0008, changing to 0.2913 ± 0.0008 after 3 months, while group B showed similar nonsignificant changes. There were no statistically significant differences in wear between both groups at any time point. Conclusion Retentive forces decrease with increasing cyclic loading. However, both materials displayed acceptable retentive values. Wear values were nonsignificant between two studied groups.

Effect of metallic substrate and rubber elastic materials over passive constrained layer damping on tool vibration during boring process

Tool vibration is a key factor that affects surface finish, generates noise, and reduces the tool life during conventional boring because of the excessive overhanging length of the tool holder. The interaction between the dynamics of the machine tool and the boring process led to progressive vibration. The creation of appropriate mechanisms in reducing tool vibration will help manufacturing industries to become more productive. In this research, in order to control vibration in the overhanging boring bar, a passive vibration control method was employed. Constrained layer dampers consist of boring bar, substrate, and elastic materials and it is used to minimize tool vibration produced during boring operation. The investigation utilized computational analysis through the ANSYS Workbench platform, employing key parameters such as the overhanging length of the tool holder (100, 150, and 200 mm), substrate material (aluminum, brass, and copper), and elastic material (Nitrile rubber, Natural rubber, and polyurethane). A comprehensive series of 27-run boring experiments were conducted to assess the impact of the constrained layer damper on tool vibration and cutting properties. The results of the study revealed remarkable improvements in various performance metrics. The constrained layer damper demonstrated an impressive 98% reduction in tool vibration, signifying its efficacy in dampening vibrational forces during the boring operation. Furthermore, a substantial 83% decrease in surface roughness was observed, indicating enhanced machining precision and surface finish. The constrained layer damper also exhibited a noteworthy 97.5% reduction in tool wear, highlighting its ability to significantly prolong tool life under challenging machining conditions.

ELECTRODE WIRE FEEDER FOR MIG/MAG AND TIG WELDING PROCESSES

The electrode wire feeding mechanisms of welding machines are designed to transport the electrode wire from the spool to the welding zone at a constant, predetermined speed or at a speed that varies according to a given law. One of the most promising areas for improving arc welding and surfacing equipment is to control the transfer of electrode metal by pulsing the electrode wire. Therefore, the feeding mechanisms of welding machines must ensure compliance with the conditions of continuous feeding at a constant speed or pulsed feeding with an intermittent movement. The problem of forming pulses with the required parameters can be solved by feeding mechanisms with a vibration drive. The main advantage of such a technical solution is the ability to produce pulsed motion with controllable frequency and amplitude parameters. Due to the high resolution of movement and high dynamic properties in transient motion modes, vibration-driven feeding mechanisms are able to provide high accuracy of bar material feeding into the working area of technological equipment. The principle of operation of such a mechanism is based on the transformation of spatial vibrations into linear displacements. The analytical dependencies obtained in this work allow us to determine the parameters of electrode wire movement by the vibratory feeding mechanism. The proposed technical solution makes it possible to provide different movements of the wire along its axis, and changing the pulsation mode is made possible by adjusting the oscillation frequency of the drive.

Anti-Roll Bar Optimization of an Urban Electric Bus

Stiffness and stability are of high importance for vehicles. Existing suspension systems are working for vehicle stability increasing and they are not limited to own. One of the stability increaser extra elements is the anti-roll bar. The anti-roll bar is a suspension system supporter in vehicles. However, bar stiffness plays a critical role in vehicle stability. Bar stiffness can be managed on the predefined limitations. Therefore, a light, effective, and reliable vehicle system can be obtained. In this study, an urban electric bus anti-roll bar optimization was conducted numerically. For optimization, the bar diameter was changed between 25mm and 40mm. S235, 50CrV4, AISI 1065, and AL 7075 were selected for material comparison. According to vehicle stability limitations under the lateral 1 m/s2 acceleration, different bar diameters and material specifications were analyzed with the finite element method. Results of this study showed that the highest stiffness and the lightest bar can be achieved with a 36mm diameter and AISI 1065 steel combination. Obtained results can lead to vehicle stability studies in the future.

Impact of the Bars Behavior on the Design of Soft Tensegrities

Abstract Soft tensegrity is a recent concept, which can be described as a prestressed assembly of soft cables in tension and bars in compression. In this paper, we investigate the impact of the bar behavior on the mechanical properties of a tensegrity. This is achieved through the change of bar material, from soft (e.g., silicone) to stiff (e.g., steel) materials. First, we show that it is possible to make a self-supporting tensegrity where both cables and bars are made of soft material. Second, we highlight that the bar material impacts the isotropy of the stiffness matrix of the tensegrity and the range of achievable stiffness. Lastly, we demonstrate that the bar material has a significant impact on the precision of stiffness variation, when active elements are integrated into the tensegrity. From these effects, we extract design guidelines for the choice of bar material in a soft tensegrity.

Surface Polishing of an Inconel 625 Bar by a Super-Fast MAF Process for a Solenoid Valve Stem Used in a Hydrogen Tank

This study explores a super-fast magnetic abrasive finishing (MAF) process for polishing the surface of an Inconel 625 bar workpiece for a hydrogen solenoid valve stem. The Inconel 625 bar was chosen to replace the existing STS 316 bar material, previously used for a hydrogen solenoid valve stem. The cylindrical surface of Inconel 625 bars was polished by a super-fast MAF process with high rotational speeds of 1000, 5000, 15,000, and 25,000 RPM and a super-strong magnetic field of 550 mT. The polishing characteristics of this process were evaluated according to the type of abrasives, rotational speeds of the workpiece and processing time. As a result, a super-smooth Inconel 625 bar was successfully achieved, with a surface roughness (Ra) reduced from 0.31 μm to 0.02 μm under the optimal conditions (15,000 RPM, CNT particles (0.04 μm), PCD diamond abrasive (1 μm), Fe (#200), 0.5 g of light oil, and 16 min of processing time). Also, the Ansys analysis results showed suitable strain, equivalent stress, and safety factor of the Inconel 625 bar. This confirmed that, after a super-fast MAF process, an Inconel 625 bar is feasible for application in Hydrogen (H2) tanks instead of a conventional STS 316 bar.

Performance assessment of LC3 concrete structures considering life-cycle cost and environmental impacts

Developing green materials for infrastructure construction is of vital importance for sustainable development. Limestone calcined clay cement (LC3) is an appropriate alternative for the reduction of CO2 emissions and resource consumption in the cement industry. Recycled concrete aggregate (RCA), seawater and sea sand are potentially advantageous from a sustainability perspective, especially in coastal regions. Fiber-reinforced polymer (FRP) bars with excellent corrosion resistance are ideal alternative materials for steel bars in a corrosive environment. In this paper, a new type of green concrete structure incorporating LC3, seawater, sea sand, RCA, and FRP bars was investigated, and the performance was assessed to verify the considerable sustainable advantages while considering life cycle cost and environmental impacts. The results showed that the proposed LC3 concrete exhibited lower environmental impacts: compared with traditional concrete, and the CO2 and energy consumption of LC3 concrete were reduced by 32%–41.7% and 23.3%–28%, respectively. Although the initial cost was higher for LC3 and CFRP bars, this disadvantage could be offset by their longer service life and lower maintenance costs during their life cycle. Compared with traditional RC structures, the total cost, CO2 and energy consumption in the life cycle were reduced by 39%, 30.5%–65.4%, and 18.5%–58.9% for the LC3 concrete structure, respectively. In contrast to the life cycle cost, the LC3 replacement ratio had a negative effect on the environmental indices for the LC3 concrete and structure. Considering the promising advantages in economy and environmental impact, the proposed LC3 concrete and structure provides an effective approach for the sustainable development of the construction industry.

Numerical Analysis of an Innovative Double-Strap Joint for the Splicing of Near-Surface Mounted Fiber-Reinforced Polymer Bars for Reinforced Concrete Beam Strengthening

The issue of the cut-off splicing of an additional fiber-reinforced polymer (FRP) bar in the near-surface mounted (NSM) technique for reinforced concrete (RC) beam strengthening exposed dominantly to bending is insufficiently investigated. A possible solution of this issue is a new proposed technique: a double-strap joint. It implies the widening of the groove at the cut-off location and the symmetrical installing of additional supplements of FRP reinforcement. In this research, beam strength has been determined for the following cases: additional NSM FRP reinforcement without a cut-off, with a cut-off, and without overlapping, and with different lengths of splice overlapping. A nonlinear analysis based on the finite element method (FEM) has been applied. The length of the cut-off splice of the additional FRP reinforcement with glass fibers (GFRP) was 20Ø, 40Ø, and 60Ø. The validation of the numerical model and a comparison of the results were conducted by using the authors’ experiments. It has been shown that, in the case of a cut-off of NSM GFRP bars, a significant loss in strengthening efficiency occurs, and that, with an increase in the overlapping length, this loss decreases. An overlapping length of 60Ø provides full strengthening. An efficiency assessment was carried out via the use of a parametric study, varying the FRP bar material type and its diameter for a constant splicing length.

Review of SHPB Dynamic Load Impact Test Characteristics and Energy Analysis Methods

Since the split-Hopkinson pressure bar (SHPB) test technology was proposed, it has played an important role in the study of dynamic mechanical properties of materials under the impact of dynamic load. It is a major test technology for the study of dynamic mechanical properties of materials. The expansion of the range of materials studied has also posed a challenge to the SHPB test technique, requiring some improvements to the conventional SHPB test apparatus and analysis methods to meet the test conditions and ensure the accuracy of its results. Based on a systematic review of the development of the SHPB test technique and the test principles, the main factors that influence the test’s ability to meet the two basic assumptions at this stage are analyzed, and the ways to handle them are summarized. The stress wave dispersion phenomenon caused by the transverse inertia effect of the pressure bar means that the test no longer satisfies the one-dimensional stress wave assumption, while the pulse-shaping technique effectively reduces the wave dispersion phenomenon and also has the effect of achieving constant strain rate loading and promoting the dynamic stress equilibrium of the specimen. Impedance matching between the pressure bar and specimen effectively solves the problem of the test’s difficulty because the transmitted signal is weak, and the assumption that the stress/strain is uniformly distributed along the length of the specimen is not satisfied when studying low-wave impedance material with the conventional SHPB test device. The appropriate pressure bar material can be selected according to the value of the wave impedance of the test material. According to the wave impedance values of different materials, the corresponding suggestions for the selection of pressure bar materials are given. Moreover, a new pressure bar material (modified gypsum) for materials with very-low-wave impedance is proposed. Finally, for some materials (foamed concrete, aluminum honeycomb, porous titanium, etc.) that cannot meet the two basic assumptions of the test, the Lagrangian analysis method can be combined with SHPB test technology application. Based on the analysis and calculation of the energy conservation equation, the dynamic constitutive relationship of the materials can be obtained without assuming the constitutive relationship of the experimental materials.

Precision of polyether ether ketone (PEEK) or cobalt-chrome implant bar fit to implants after mechanical cycling.

The aim of this study was to evaluate the fit accuracy of dental implant bars made of either PEEK or cobalt-chrome submitted to cycling mechanics. This was an experimental in vitro study, where units were treated with two implants and mini-abutments, joined by cobalt-chrome or polyether-ether-ketone PEEK bars. A total 20 bars were prepared (n=10 per group) and subjected to mechanical cycling tests (1 million cycles on the distal cantilever of the bar in the vertical direction, 120N and sinusoidal loading, at a frequency of 2Hz). The fit at the abutment/implant interface was measured before and after cycling, and the counter-torque of the vertical screw of the mini abutments was measured after cycling, using a digital torquemeter. Data were analyzed by three-way ANOVA and Tukey's test at 5% significance level. No statistically significant interaction was found among the three factors considered (bar material, implant positioning and mechanical cycling) (p = 0.592). No significant difference was identified in the interaction between bar material and implant positioning (p = 0.321), or between implant positioning and mechanical cycling (p = 0.503). The association between bar material and mechanical cycling was statistically significant (p = 0.007), with the cobalt-chrome bar resulting in greater misfit with mechanical cycling. There was no difference in counter-torque values between groups. The PEEK bar provided better fit of the mini abutments to the implants, even after mechanical cycling. The counter-torque of the screws was similar in all scenarios considered.

A FEM-Based Comparative Study of the Effect of Rotor Bar Designs on the Performance of Squirrel Cage Induction Motors

Induction motors (IM) are the most frequently used type of motor in the industry. The number of rotor slots, bar geometry, and conductivity of bar material have a strong impact on the torque profile and efficiency characteristics of induction motors. This study focused on investigating the effect of different rotor bar designs on motor performance by the finite element method (FEM). The IMs have been designed using the same stator core, winding, and core lengths. The total rotor bar cross-section areas are also fixed throughout all designs. In addition to the change in the number of rotor bars and geometry, the effect of copper and aluminum bar materials on motor performance was also investigated, both for single and double-layered squirrel-cage structures. The results of the study indicate that the starting torque of the motor in a 36/30-slot aluminum single-cage structure was obtained as 96.26 Nm, while the starting torque of a 36/46-slot aluminum double-cage structure was found to be 115.34 Nm. It is also found that the starting torque of the initial design can be increased by up to 19.82% by changing only the rotor bar numbers and material with the same stator and rotor size. The efficiency of the motors was determined as 86.6% for both designs. In addition to efficiency, the output torque ripple has been decreased to 2.63, which equals a 67.32% decrease in the ripple of the initial design. The improved design has an approximately 8 °C lower T2 due to better cooling performance as a result of a higher number of rotor slots.

Structure and strain state of aluminum bars at the initial phase of extrusion

The structure of insufficiently deformed areas at the non-steady phase of extrusion was studied. The tests at Kamensk Uralsky Metallurgical Works using a 120 MN press and 800 mm dia. container, in order to extrude a 355.6 mm dia. Bar was performed. The bar material is the Al–Mg–Si AD33 aluminum alloy (GOST 4784), similar to ASTM 6061. The percentage reduction was 80 %, and the reduction ratio was 5.06. After that, the macrostructure, microstructure, and average grain size along the radius, mechanical properties at room and elevated temperatures were investigated. It was found that the extruded bar macrostructure is fine-grained, homogeneous, and dense, with no nonmetallic or intermetallic inclusions. The cross-section contained several structures. The central part is weakly deformed preserving the dendritic cell structure inherited from the casting. At the circumference, a streaked structure is formed. Its components are crushed and uniformly distributed. We measured the strength at elevated temperatures and compared the results to the data available in the literature. The tested material strength almost doubled, thus indicating its incomplete softening. The ductility was also performed. The DEFORM-2D software, in order to simulate the low reduction of extrusion was used. The metal at the circumference is exposed to a greater strain from the extrusion beginning. A step-by-step analysis indicated that at the first step, the strain is localized near the die hole. In the second step, a rigid area is formed in the vicinity of the die/container liner interface. The circumference layer of metal with a 1.75–2.00 reduction of area is formed. At the bar center, this range is 0.75–1.00 (half of the circumference value). In the third step, the circumference layer with an elevated strain has a wedge-like shape. In the fourth step, the circumference layer (with elevated strain) has an equal thickness along the extrusion axis. This indicates the steady phase. The plastic strain at the bar front end is higher at the circumference than in the center. This confirms the structural analysis results. They show that the central part of the bar may retain its cast structure, while the circumference is deformed. If the bar central part is required to have some specific properties, the bar has to undergo another manufacturing operation to increase the accumulated strain. Re-extrusion processes the areas insufficiently deformed during the first extrusion.

Analyze Differences in Carbon Emissions from Traditional and Prefabricated Buildings Combining the Life Cycle

Construction, as an important producer of energy, material, and waste emissions, the high energy consumption problem has not been solved. Prefabricated buildings have become more and more popular and promoted in China in recent years. This study takes prefabricated buildings and traditional cast-in-situ buildings as research objects and divides the buildings into five stages: factory building materials production, component transportation, field installation, use, and demolition. In addition, the paper presents the calculation method of carbon emissions in five stages of construction. By calculating the carbon emissions of the two buildings in five stages, the total carbon emissions of the two buildings and the differences in carbon emissions are obtained. In particular, in this case, the prefabricated buildings and traditional cast-in-situ buildings were constructed at the same time and in the same place. It is concluded that prefabricated buildings can reduce carbon emissions by about 86 kg per square meter compared with traditional cast-in-situ buildings. In all stages of carbon emissions, the field installation stage produces the most carbon emissions. Prefabricated buildings consume more concrete, steel bar, and diesel and fewer wall materials than traditional cast-in-situ buildings.

Обоснование способа производства прутков из сплава НММц 38-2В для изготовления деталей рабочей зоны электровакуумных приборов

The paper considers critical features of the chemical composition of the 2NiCuMn 38-2V alloy bars material, which could affect vacuum purity of the electrovacuum devices working area. Taking into consideration peculiarities of the electrovacuum devices manufacture technology, it is shown that the use of cold-drawn bars in manufacturing parts of their working area is technically unreasonable. It is noted that instead of the cold-drawn bars, bars obtained by hot rotational forging could be used.

Effect of Two Different Digitally Constructed Bar Materials on The Supporting Structures of Implant-Retained Mandibular Overdenture (In-Vitro Study)

Effect of Two Different Digitally Constructed Bar Materials on The Supporting Structures of Implant-Retained Mandibular Overdenture (In-Vitro Study)

Flexural Performance of Concrete Beams Reinforced with Hybrid FRP-Steel Bars: A mini review

Reinforced concrete beams are the most generally used structural parts in building, bridges, and many other structures. In the past two decades, many investigations have been conducted using various fiber-reinforced polymer (FRP) material types /steel bars to reinforce concrete beams under flexural test. The purpose of this paper is to review the flexural performance of concrete beams reinforced with hybrid FRP and steel bars to better understand their behavior. The main parameters addressed by researchers were dimensions of beams, FRP bar material type, and hybrid reinforcement ratio. The researchers established that the use of the combination between steel and FRP reinforcement bars improves the performance of the concrete beams. Moreover, the studies showed that the ductility of the hybrid reinforced beams increased compared to that of conventional steel reinforced beams, however, it decreased when the ratio of (Af/As) increased. The application of using hybrid FRP/steel bars in reinforcing concrete beams will further increase upon utilizing techniques for reducing the brittleness and higher cost of FRP bars. The general structure of this paper consists of presenting the formulas offered by ACI 440.1R-15 building code relating to the flexural strength calculation of concrete beams reinforced with FRP/steel bars. The paper also details some of the current experimental tests and analytical works published for concrete beams reinforced with hybrid system, and outlines research directions and identifies gaps required for additional research.

Rolled metal electron plasma treatment for automotive hardware cold upsetting

One of the most important objectives of the modern car production development is to improve the quality of metal products and parts made from it, increase their efficiency, reliability, service life, bringing these indicators to the level of the world standards, ensuring the competitiveness of domestic products at the foreign market. The structural safety of motor vehicles is largely determined by the operational reliability of the constituent elements. Car fasteners made of high-carbon and alloy wire, including hardware items, are among the critical and widely used parts in mechanical engineering. The most common and progressive method of their manufacture is the cold upsetting from rolled bar material. The bar material surface condition has a significant impact on its quality. Hot rolled products from metallurgical plants are typically delivered to the processing facilities covered with scale and rust. To improve the surface quality of semifinished metallurgical products for rerolling at the stage of wire preparation for drawing, it is subjected to continuous mechanical or chemical cleaning. Traditionally, the technology of surface scale removing by etching is used in production. This method of scale removal provides a high level of cleaning, but there are problems with the disposal of spent acid solutions, reducing the steel ductility. Mechanical methods of scale removal have been widely introduced recently, although the use of mechanical scale removal devices also does not completely solve the problem. The paper considers the possibility of using advanced electron plasma treatment technologies for these purposes and the influence of traditional methods and this scale removing method from the rolled steel surface on the quality of metal preparation for upsetting.

The formation of alloy based on Al-Ti-B system by electroslag process involving dispersed engineering waste

In this article presents technological process of manufacturing Al-Ti-B rod master alloy by electroslag casting is proposed and investigated. Aluminum alloy chip waste of a grade AK7, commercial titanium of a grade VT1-00 and amorphous boron of a grade A were used as starting materials. The consumable electrode is a product in the form of a rod obtained by mouthpiece pressing of a mixture of crushed starting materials in a mass ratio of AK7 : VT1-00 : amorphous boron = 97:2:1. According to the proposed technology and the ratio of starting materials in the charge composition, an experimental bar material of the Al-Ti-B ligature was obtained, electron microscopic, micro-X-ray spectral studies, the stereometric analysis of the structure which showed the priority interaction of titanium with boron.