Diameter Steel Rods Research Articles

Development and Performance Evaluation of a Hand-Pushed Tiger Nut Harvester

Harvesting is one of the major problems encountered by tiger nut farmers in Nigeria. Manual harvesting system is the most commonly used method. This process is costly, labour intensive and time-consuming. The process does not also give farmers adequate returns to enable them to break even due to huge losses encountered. The objective of this study was to design, construct and evaluate a hand-pushed harvester that would eliminate the challenges being faced by small and medium tiger nut farmers during harvesting. Materials selection for constructing the harvester were based on their durability and availability, affordability and ease of replacement if damaged. They include mild steel (3 mm, 5 mm), 30 mm galvanized steel hollow pipe, 10 mm diameter steel rod, and 400 mm steel tyre. The developed harvester was evaluated at the experimental farm of the Institute for Agricultural Research (IAR). Results of the study show that the average field capacity ranges from 0.28 – 0.33 ha/h while the average field efficiency was between 77.78 – 80.49% depending on operating speed, moisture content and other properties of the soil. No field damage was recorded when the harvester was used as against an approximate 10.50% damage recorded in the manual harvesting method.

Bending Behavior of Splice Connection for Mengkulang Glued Laminated Timber Beam

This paper presents the experimental bending strength of steel dowelled splice glulam timber made of 'Mengkulang' species. Bending tests were conducted under a four-point bending load. Six (6) glulam specimens with 45mm x 90mm x 1800mm were loaded. Three (3) specimens were full beams as the control and three (3) splice beams dowelled with grade 8.8; 20 mm diameter steel rod. The embedded length of the steel dowel was 60mm and glued at 2mm thickness on both sides. Results show that the bending strength of the glulam control beam performed 74.18% higher than the splice beams with an increment of 58.26% displacement. Keywords: Structural material, flexural strength, failure mode, dowelled connection eISSN: 2398-4287© 2021. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v6iSI4.3029

Design, Construct and Evaluation of a Single Row Hand-Pushed Mechanical Weed Control Machine

Weed control is one of the major problems in crop and vegetable production in Nigeria. Most of the peasant farmers use manual weeders in their cultivation, a process that is costly, labour intensive and time consuming. The process does not also give the farmer adequate returns to enable him breakeven. It is, therefore, necessary to design a weeding equipment which minimize the human effort and provide efficient work output for the peasant farmer. This study focus on designing, construction and evaluation of a hand-pushed weed control machine that would eliminate the challenges being faced by the farmer in weeding. Materials selected to suit the construction of the weeder are durable and locally available, easily replaced if damaged and at affordable cost. They include mild steel (3mm, 5mm), 30 mm circular (hollow) pipes, 10 mm diameter steel rod, and 40 cm pneumatic tyre. The developed weeding machine was evaluated in the experimental farm of IAR with impressive results. It works well in sandy loam soil of about 25.65% moisture content and requires less labour force compared to the manual hoe. It has about 84.7% weeding efficiency, 0.0129ha/hr effectivefield capacity, 0.019ha/hr theoretical field capacity and 68% field efficiency. The average cost of the weeding is N21, 000:00.
 Keywords: Manual weeding, hand-pushed weeder, weeding efficiency, field efficiency

Performance Evaluation of Different Types of Shear Connectors in Steel–Concrete Composite Construction

AbstractShear connectors are designed in steel-concrete composite construction to transmit the longitudinal shear, to prevent separation of steel and concrete slabs, and also to increase the structural efficiency of the whole system. In this study, the performances of different types of shear connectors in steel-concrete composite specimens are evaluated by conducting push-out tests under monotonic loading conditions. An ISMB 200 @ 25.4 kg/m universal steel beam measuring 400 mm and a reinforced cement concrete slab measuring 300 mm with a breadth of 200 mm and a thickness of 200 mm reinforced with 8 mm diameter steel rods are used for the experimental study. The results reveal that the load-slip relationships for various types of shear connectors and failure mechanisms are obtained to identify those shear connectors which are more relevant to the steel - concrete composite members.

Study of Bond Characteristics of Reinforced Waste Glass Aggregate Concrete

The conformity of properties of waste glass aggregate with conventional aggregate was found out. Nine cubes (150mm x 150mm x 150mm) were cast out of which three were used for control concrete, three were fully replaced with waste glass as coarse aggregate, three were partially replaced(50%) with waste glass as fine aggregate. Six cylinders (150mm x 300mm) were cast out of which two for control concrete, two cylinders with coarse aggregate fully replaced with waste glass aggregate(WGA) and remaining two cylinders with partially replaced (50%) fine aggregate with waste glass aggregate. Cured specimens were subjected to compression and split-tensile test to ascertain the characteristic compressive strength and split tensile strength. Since the surface of the coarse aggregate plays a significant role in bonding of the rebar in reinforced concrete, pull-out test on both control and Waste Glass Aggregate (WGA) cube specimens (150mm x 150mm with 20mm diameter steel rods) were conducted. Scanning Electron Microscopy (SEM) analysis has been done for better understanding of bonding properties in waste glass fine aggregate(WGFA) and waste glass coarse aggregate(WGCA) concrete. Comparison of the results with that of control specimens showed that waste glass could be effectively used as aggregates in reinforced concrete construction.

Void Closure Behavior in Large Diameter Steel Rod during H-V Rolling Process

In order to reveal the mechanism and condition of void closure in large diameter steel rod during horizontal-vertical (H-V) groove rolling process, a three-dimensional thermomcchanically coupled finite element model was established for 9-stand H-V groove rolling process aiming at a ϕ 150 mm steel rod production line. A spherical hole with diameter from 2 to 10 mm was preset into the center of continuous casting billet with a rectangle cross section of 300 mm×360 mm in this model to simulate the void defect, and then finite element analyses were carried out to observe and quantify the void shape evolution in each pass on the three orthogonal coordinate plane sections. The results showed that the void was formed roughly in the reduction and extension directions, and crushed gradually from spherical shape to an approximate ellipsoid, micro-crack and finally to be closed. A quantitative analysis was carried out by using elliptic radii and closure ratio to describe this evolution process; it indicated that the longest axis of the ellipsoid coincided with the rolling line, and the second and third axes were alternatively horizontal and vertical on the exit cross section according to change of the reduction direction in H-V groove. The void closure behavior during H-V rolling was more complicated than that of common horizontal rolling, and the influence of groove type and the extension coefficient on the void closure ratio was presented. Finally, a pilot rolling experiment was performed on a 5-stand H-V experimental mill to verify the numerical simulation results, and the experimental results are in good agreement with the numerical simulation results.

The Experimental Research Based on SHPB Test of the Rocks Plastic Damage Cumulative Effect

This article to research through SHPB test of the rocks in the plastic damage under the cumulative effects. This paper selects bullets for the diameter steel rods, the bullet hit by a fixed speed when fixed, selects the two kinds of circumstances for gas chamber pressure such as P = 0.6 MPa and P = 0.7 MPa. It is concluded that the main important conclusions： Test specimen didn’t reach the effect for ,Limestone which is no initial damage to absorb lesser energy, as the same time the internal stones damage were also lower, and with the impact times accumulation, limestone damages degree were increasing, eventually make the specimen destroy. The internal of rock specimens are low destroy, when has the same effect, specimens receiving the maximum stress by lesser,when the internal damage can cumulative increases to certain value, and is suffered the same stress effect, finally the maximum stress will be decreased. For rocks material at repeated impact as low speed ,under this action show the obvious plastic damage accumulation effect

Effect of light-curing units on push-out fiber post bond strength in root canal dentin

The purpose of this study was to evaluate the effectiveness of different light-curing units on the bond strength (push-out) of glass fiber posts in the different thirds of the root (cervical, middle and apical) with different adhesive luting resin systems (dual-cure total-etch; dual-cured and self-etch bonding system; and dual-cure self-adhesive cements), Disks of the samples (n = 144) were used, with approximately 1 mm of thickness of 48 bovine roots restored with glass fiber posts, that were luted with resin cements photo-activated by halogen LCU (QTH, Optilux 501) and blue LED (Ultraled), with power densities of 600 and 550 mW/cm2, respectively. A universal testing machine (MTS 810 Material Test System) was used with a 1 mm diameter steel rod at cross-head speed of 0.5 mm/min until post extrusion, with load cell of 50 kg, for evaluation of the push-out strength in the different thirds of each sample. The push-out strength values in kgf were converted to MPa and analyzed through Analysis of Variance and Tukey’s test, at significance level of 5%. The results showed that there were no statistical differences between the QTH and LED LCUs. The self-adhesive resin cement had lower values of retention. The total-etch and self-adhesive system resin cements seem to be a possible alternative for glass fiber posts cementation into the radicular canal and the LED LCU can be applied as an alternative to halogen light on photo-activation of dual-cured resin cements.

Behavior of soil retaining walls on deformable foundations

Cost-effectiveness evaluations for soil retaining structures require better knowledge of the integrity and serviceability of these structures subjected to foundation settlements. As a preliminary study on the performance-based design of soil retaining structures that takes into account the influence of foundation settlements, the settlement-tolerating characteristics of cantilever soil retaining walls (CWs) placed on deformable foundations were explored using a 0.6 m-high model cantilever wall backfilled with rhombically stacked 1.96 mm uniform diameter steel rods used as two-dimensional backfills of the wall. Screw jacks were used to simulate a non-yielding foundation and three types of spring with various spring constants were used to simulate deformable foundations with maximum foundation settlements of approximately 2%, 5%, and 9% of the total wall height. It was found that the measured values of the lateral pressure coefficient ( K f) increased significantly with a decrease of subgrade stiffness, k v (or an increase of maximum foundation settlement, S max). The measured values of K f for the CWs placed on deformable ground may be greater than those for the at-rest ( K o) condition when S max is greater than 3% of the total height of the wall ( H t). For the tested cantilever wall with moderately high safety factors against sliding and overturning based on a commonly adopted assumption of an unyielding foundation, significant decreases in safety factors associated with the increase in S max were observed. Equations for additional margins of design lateral pressure coefficient and/or safety factors against sliding and overturning for the wall, expressed as a function of maximum foundation settlement, are proposed to substantiate the safety evaluation of soil retaining walls situated on a deformable foundation.

Flexible piezoelectric transducer for ultrasonic inspection of non-planar components

This paper presents the fabrication and characterisation of a flexible ultrasonic transducer using commercially available PZT-5A piezoelectric fibers which are lapped to form rectangular piezoelectric elements. The key feature in the device construction is the inclusion of gaps between the piezoelectric fibers to ensure good flexibility in the plane normal to the fiber direction. The spatial response of the transducer ultrasonic output was assessed using acoustographic imaging. The flexibility of the transducer and its applicability in pulse-echo mode on curved sections was demonstrated by testing on a 38 mm diameter steel rod. The transducer response was found to be broad band and highly non uniform but good pulse-echo performance was achieved at 5 MHz.

TU‐FF‐A3‐06: Dose Calculation in Presence of a Metallic Object Using Megavoltage Cone‐Beam CT

Purpose: CT image artefacts caused by the presence of metallic objects hinder organ delineation and preclude precise dose calculation. In contrast, the presence of high atomic number material has relatively little impact on the image quality of Megavoltage Cone‐beam CT (MVCBCT). The objective of this work was to determine if MVCBCT could be used for accurate dose calculation in the presence of metallic objects.Material: Experiments were performed with a 16cm diameter cylindrical water‐equivalent phantom. MVCBCT and kVCT images of the phantom were acquired with and without a 1.5 cm diameter steel rod (3 mm wall thickness) sitting on the phantom. Using a treatment planning system, dose distributions were calculated for a 6 MV 10 cm square field AP beam for these configurations. Dose measurements were performed using an ion chamber placed at isocenter and mosfet detectors placed at 35 locations in the phantom. Measured and calculated dose values were compared. Results: Without metal, dose calculated in the phantom using either the kVCT or the MVCBCT image corrected for cupping artefact were all within 2% of each other and of the measured values, showing the ability to use the MVCBCT for dose calculation. In the presence of the metallic object, erroneous density values, around the rod, made dose calculation on the kVCT unreliable. MVCBCT provided correct density values (within 5%) and differences between measured and calculated dose values were on average 3.2% (SD 3.4%). The two largest differences (10.6% and 8.9%) were found in a high dose gradient region below the rod. Conclusion: MVCBCT can be used in a treatment planning system for dose calculation in the presence of metallic objects. Results for non‐cylindrical geometries will also be presented.This research is supported by Siemens.

Single-pulse arc production of carbon nanotubes in ambient air

Multi-wall nanotubes (MWNTs) of carbon were produced by pulsed arc discharges between a room temperature sample and a counter-electrode, with peak currents of 7–100 A, and pulse lengths of 0.2–26 µs, in open air at selected locations on the sample. The samples were 10 × 10 mm2 graphite plates, carbon-coated 200 mesh copper grids, and Ni-coated glass slides. The counter-electrodes were graphite in the form of 1 × 4 mm2 bars or 4 mm diameter rods with a cone tip of 28°, or 0.1 mm diameter steel rods. Randomly oriented MWNTs (typically 5–15 walls) with a diameter of ∼ 10 nm and lengths of up to 3 µm were produced on the samples with a single 0.2 µs pulse, implying linear growth rates of up to 15 m s−1. MWNTs were produced with both polarities and with all types of counter-electrodes used when the substrate contained carbon. Near vertically oriented MWNTs were deposited on the Ni/glass samples using a graphite counter-electrode. The simplicity, rapidity and selectivity of the process may facilitate wider study and practical application.

Penetration mechanisms of non-deforming projectiles into reinforced concrete barriers

Static and dynamic penetration tests of reinforced concrete (RC) slab specimens are described and discussed. The experimental study was aimed at a better understanding of mechanisms that are involved in dynamic penetration, through their identification in static tests, and by establishing their relative influence in similar dynamic cases. The RC specimens were square plates, and they were made of 30 MPa concrete. The non-deforming steel penetrator was a 50-mm diameter steel rod with a conical nose of 1.5 aspect ratio. Impact penetration tests were carried out with an air gun, which launched the projectiles at velocities of up to 300 m/sec. The static tests were conducted using a closed loop displacement control actuator, where the penetrator was pushed at a constant rate of displacement into the specimen. The static tests reveal important mechanisms that govern the penetration process and therefore contribute to a better understanding of RC barriers resistance to non-deforming projectiles impact.

10.2172/1116744

INL researchers have proposed prototypes for future lightweight armor systems that reside in a technology gap between explosive reactive armor and passive armor. The targets were designed to react under impact and throw a steel front plate into the path of the projectile, forcing the projectile to engage more of the front plate during its penetration process. These prototypes are intended to exhibit the enhanced efficiency of explosive reactive armor without the collateral damage often associated with explosive reactive armor. One of the prototype systems, Semi Energetic Reactive Armor (SERA), functions similarly to explosive reactive armor, but features a reactive material that reacts much slower than explosive reactive armor. Two different SERA test groups were built and featuring different ratios of aluminum Teflon(copyright) powders pressed into 0.5 in. thick energetic tiles and sandwiched between 0.25 in. thick RHA plates. The other prototype system, Non Energetic Reactive Armor (NERA), utilizes the strain energy in compressed rubber to launch a front flyer plate into the path of an incoming projectile. It is comprised of a 1 in. thick rubber layer sandwiched between two 0.25 in. thick RHA plates with bolt holes around the perimeter. Bolts are inserted through the entire target and tightened to compress the rubber sheet to significant strain levels (approximately 40%). A fourth group of targets was tested as a control group. It featured a 0.5 in. thick rubber sheet sandwiched between two 0.25 in. thick RHA plates, similar to the NERA test articles, but the rubber is uncompressed. The four test groups (uncompressed rubber, compressed rubber, 70/30 Al/PTFE, 50/50 Al/PTFE) were each fabricated with three identical test articles in each group. All twelve targets were subjected to ballistic testing at the National Security Test Range on July 17, 2013. They were tested with 0.5 in. diameter steel rods shot at a consistent velocity at each target. In order to characterize the energetic materials, break wires were embedded in the targets and burn velocities were measured. The residual mass method was used to compare the target performance of each group and final performance data is presented below.

Seismic Stabilization of Historic Adobe Structures

Many historic adobe structures in the southwestern United States and throughout the world are vulnerable to destruction or damage by earthquakes. In the recent Northridge earthquake in Los Angeles, a significant number of the remaining, unretrofitted adobe structures dating to the 18th and early 19th century were extensively damaged. Yet it has been observed that many other adobes have performed well during large seismic events. Responses differ because low-strength adobe, when used in thick walls, develops cracks during seismic events, but these cracks do not necessarily lead to catastrophic building collapse. The concept of seismic retrofitting based on improving the stability of the adobe buildings, rather than the more conventional criterion of improving the strength, seems to be a valid approach. The objective of such a concept is to prevent walls from overturning by restricting the relative displacement of blocks formed following cracking, thereby enabling the structure to dissipate energy by friction and rocking without catastrophic collapse.Shaking table tests of model adobe buildings have been carried out. Various types of simple retrofitting measures that were evaluated were designed to be relatively noninvasive and respectful of the historic fabric of the building. These measures consisted of thin, flexible horizontal or vertical straps applied to both sides of walls and small diameter steel rods inserted within the walls used in conjunction with a thin wood bond beam. The intent of these measures was to provide overall structural continuity rather than strength improvement. The results of the tests involving nine 1:5 scale model buildings clearly demonstrated the effectiveness of the stability-based techniques. Wall height-to-thickness ratios were varied from 5 to 11, and maximum table displacements of ±38 cm (prototype domain) were used. Some retrofitted models were able to withstand twice the displacement that resulted in collapse of an unretrofitted model. Additional tests carried out on two instrumented 1:2 scale model adobe buildings further demonstrated the effectiveness of the retrofitting measures.

Flexural behaviour of reinforced concrete beams repaired with styrene—butadiene rubber latex, silica fume and methylcellulose repair formulations

The use of plain cement mortar in repair works is limited to unimportant works because of its poor adhesive bond to the substrate and its performance from the point of view of durability. Polymer-modified cement mortar has replaced plain mortar for these reasons. Also, the incorporation of silica fume and methylcellulose in repair systems has been found to provide a better durability and overall performance. This paper presents the results of an experimental investigation of the flexural behaviour of six reinforced concrete beams. Five beams were repaired using five different repair systems, namely plain cement mortar and mortars modified with latex (L), latex and silica fume (L—S), latex silica fume and methylcellulose (L—S—M), and silica fume and methylcellulose (S—M). The sixth beam was an unrepaired control beam. The repair procedure was carried out while loading the beams, to match the on-site practice. The size of the beams was 100 X 150 X 1200 mm and they were reinforced with two 10 mm diameter steel rods with a yield strength of 551 MPa. The test results showed that beams repaired with L, L—S and L—S—M mortars successfully restored the structural capacity of the unrepaired beam, besides improving the durability, crack pattern and toughness characteristics of these beams. The use of plain or S—M mortars showed a poor structural performance since they exhibited early separation along the contact interface with the substrate, as well as reduced ductility and toughness.

Corrections

The water valve box lid lifter designed by Gene Divis, winner of OpFlow's “Gimmicks and Gadgets” contest (OpFlow July 1981), should be made of 3/8‐in. (1‐cm) diameter steel rod, not 3.8‐in. as reported in the article.

Seismic Stabilization Of Historic Adobe Buildings

Many historic adobe structures in the Southwestern United States are vulnerable to destruction or damage by earthquakes. In the recent Northridge earthquake in Los Angeles, a significant number of the remaining, unretrofitted adobe structures dating to the 18th and early 19th century period were damaged extensively. Yet, it has been observed that many other adobes have performed well during large seismic events. This dichotomy exists because low strength adobe, when used in the form of thick walls, develops cracks, but these do not necessarily lead to catastrophic building collapse. The concept of seismic retrofitting based on improving the stability of the adobe buildings, rather than the more conventional criterion of strength, seems to be a valid approach. The objective of such a concept is to prevent walls from overturning by restricting the relative displacement of blocks formed following cracking thereby enabling the structure to dissipate energy by friction and rocking without catastrophic collapse. Shaking table tests of model adobe buildings have been carried out. Various types of simple retrofitting measures were evaluated that were designed to be relatively noninvasive and respectful of the historic fabric of the building. These measures consisted of thin, flexible horizontal or vertical straps applied to both sides of walls and small diameter steel rods inserted within the walls, which were used in conjunction with a thin wood bond beam. The intent of these measures was to provide overall structural continuity rather than strength improvement. The results of the tests involving seven 1:5 scale model buildings clearly demonstrated the effectiveness of the stability-based techniques. Wall height-to-thickness ratios were varied from 5 to 11 and maximum table displacements of ± 38 cm (prototype domain) were used. Some retrofitted models were able to withstand twice the displacement that resulted in collapse of an unretrofitted model. Transactions on the Built Environment vol 15, © 1995 WIT Press, www.witpress.com, ISSN 1743-3509

Wheeling Suspension Bridge

The Wheeling Suspension Bridge in Wheeling, West Virginia, built in 1849, is the world's oldest cable suspension bridge and is 1,010 ft in span. It still serves the function of connecting the city of Wheeling with Wheeling Island in the Ohio River and has been designated a National Historic Civil Engineering Landmark. The bridge is a cable-suspended structure with four 7.5-in. diameter cables containing 2,200 10-gage wrought iron wires laid parallel in each cable and wrapped with wire. The bridge is stiffened by Howe-type timber trusses and 1.25 in. diameter steel rod vertical supporting members. Diagonal, wire rope stay-cables an inch or more in diameter reinforce the ends of the span. Lateral sway cables, also known as wind guys, connect to some of the floor beam extensions. On each side of the alignment of the bridge, they are buried more than 100 ft in concrete and rolled steel deadmen. The bridge is asymmetrical; the top of the West Tower is at elevation 738.9 ft and that of the East Tower is at 760.5 ft. Many improvements have been made to the bridge as design loads have changed. Sway cables were added in 1860. In 1872, diagonal stay cables and stiffening trusses made their appearance, and more of these were added in 1886. A major rehabilitation in 1956 included the addition of the present-day floor beams; second and third rehabilitations took place in 1983 and 1999.