Aluminum Bar Research Articles

Influence of sugar beet storage duration on root responseto non-destructive impacts

Abstract For the purpose of this paper, sugar beet roots were loaded by creating the impact of aluminium bars falling from different heights. The time history of the force at the contact between the sugar beet root and the bar was measured. The response of the sugar beet root to the impact was evaluated in terms of surface displacement. This displacement was measured using a laser vibrometer. The displacement was studied in the time and frequency domain during the postharvest period, up to 71 days after crop collection. The measured parameters describing the sugar beet response were significantly sensitive to the storage duration, namely in the frequency domain. Correlations between the storage duration and the main parameters of both the force and surface displacement were identified (p < 0.05).

Automatic Positioned Controller Parabolic solar Dish Prototype

This paper discusses the development of dual axis parabolic dish tracker application for automatized position power system. This prototype tackles solar light in solar sterling design system or concentrated photovoltaic design by implementation of digitalize control circuit to enhance CSP and CPV applications. A normally 121.92cm dish is designed with H-bridge controller technique & Slew drive actuator mode to capture solar irradiances. The surface of dish is polished with 12 aluminum bars to concentrate the solar irradiance in one reflective axis. Economic justification for Pakistan’s industries would be possible if these automated based renewable prototypes are promoted in market in compare of single PV panel. This prototype controls the all weather conditions, utilizing real time flexible timing control strategy and photoelectric tracking scheme to provide cost effective product for industrial power generation applications. This locally adaptive material based prototype encouraged the result about 33% efficient with compared to photovoltaic panel.

Representational Bias in the Radial Axis in Children With Dyslexia: A Landmarks Alignment Study

To better identify the distinctive characteristics of space representation in the radial dimension, we have proposed a new paradigm: the landmarks alignment task where two parallel aluminum bars were radially presented. Children had to move a landmark along one bar and place it at the same location as the reference landmark placed by the examiner on the parallel bar. The major interest of this task was its capacity to assess space representation in the radial dimension when considering a spatial landmark that oriented the subject’s attention toward the orthogonal dimension. The most important result showed that in the radial dimension children with dyslexia exhibited a forward bias on the left bar, meaning a mental underrepresentation of the leftward peripersonal space and/or a mental overrepresentation of the rightward peripersonal space. Furthermore, reading discrepancies were correlated with radial forward bias on the left bar. The experiment was also conducted in the lateral axis, showing a pseudoneglect behavior in children without dyslexia. Our landmarks alignment task had the advantage of being able to assess space representation in a complex environment. The forward radial representational bias in children with dyslexia could have implications for spatial orientation in peripersonal workspace in school situations.

Experimental Study to Minimize The Burr Formation in Drilling Process With Artifical Neural Networks (ANN) Analysis

In present work, drilling of a through a hole in an aluminium bar has been observed the formation of a burr. The unwanted material raised beyond the work piece called burr. The minimization of the burr is important for manufacturing aspect which reduces cost and increases the life of the product. In this paper drilling on aluminium work piece experimental test has been conducted three parameters drill diameter, Point Angle and spindle speed and each of the parameter three different level (maximum, intermediate and minimum)value has been chosen. The each set of an experiment the burr height and thickness has been measured. The effect of each parameter which reduces the burr height and thickness has been identified. In this paper, artificial neural networks (ANN) model are developed for comparining the experimental results.The ANN modeled values show very close matching with the experimental results.

Two-dimensional physical modelling of soil displacements above trapdoors

Geosynthetic reinforcement has been increasingly used over voids or piles in soft soil to support embankments and minimise differential settlement. Due to differential settlement, soil arching is formed and less pressure is applied onto the reinforcement. This problem is often simulated using trapdoor tests. The reinforcement effect on displacement and soil arching has not been fully understood. In real applications, multiple voids or multiple spans of piles exist under embankments. The effects of multiple voids or spans of piles on displacement and soil arching have not been well investigated. This paper reports a series of two-dimensional trapdoor tests conducted to investigate soil displacements above single and double trapdoors without or with reinforcement. Analogical soil, made of aluminium bars, was used as embankment fill. Paper was used as reinforcement. Two different embankment heights were investigated. The experimental tests showed that both embankment height and reinforcement reduced the vertical displacement on the top of the embankment, and higher embankment caused more soil failure at the edge of the stationary support but reduced the vertical stress on the reinforcement. The maximum tensile strain happened at the edges of the trapdoor. Trapdoors spaced at twice the trapdoor width did not cause much interaction between each other.

Implementation of an axisymmetric drop shape apparatus using a Raspberry-Pi single-board computer and a web camera

This paper describes the implementation of an axisymmetric drop shape apparatus for the measurement of surface or interfacial tension of a hanging liquid drop, using only cheap resources like a common web camera and a single-board microcomputer. The mechanics of the apparatus is composed of stubs of commonly available aluminium bar, with all other mechanical parts manufactured with an amateur 3D printer. All of the required software, either for handling the camera and taking the images, or for processing the drop images to get the drop profile and fit it with the Bashforth and Adams equation, is freely available under an open source license. Despite the very limited cost of the whole setup, an extensive test has demonstrated an overall accuracy of ±0.2% or better.

Optical fiber sensor based on a polymer optical fiber macro-bend to study thermal expansion of metals

Thermal expansion is an important parameter for characterization of metals. As metal is heated, the molecules vibrate more violently and expand in all direction. Investigators have focused to study the thermal strain. However, the amount of expansion is difficult to measure. An attempt has been made to develop an apparatus using optical technique. The principle of this system is the transformation of length changes into changes of light intensity. The purpose of this work is to design and develop an optical fiber sensor based on a macro-bend of a polymer optical fiber. In this system, thermal expansion of metal was converted into the rolling of a needle in which placed beneath a flat bar of metal. Optical fiber sensor was attached to the ended section of a needle. As the crimp tube of the fiber sensor was moved due to thermal expansion of metal, the bend radii of optical fiber sensor was changed. As a sequence, the loss induced by the bending effect was depended on the expansion of metal that changed with temperature. In this study, we utilized optical fiber sensor to monitor and compare the thermal expansion of copper, brass and aluminum. According to our experimental results, the linear response with temperature was reported. The measured values of coefficient of thermal expansion was analyzed to be 0.45, 0.35 and 0.32 a.u./°C for aluminum bar, brass bar and copper bar, respectively. In addition, the effect of the size of the diameter of a needle on the response of bending loss was investigated.

An in situ thermo-mechanical rig for lattice strain measurement during creep using neutron diffraction.

A long-term high-temperature testing stress rig has been designed and fabricated for performing in situ neutron diffraction tests at the ENGIN-X beamline, ISIS facility in the UK. It is capable of subjecting metals to high temperatures up to 800 °C and uniaxial loading under different boundary conditions including constant load, constant strain, and elastic follow-up, each with minimum of external control. Samples are held horizontally between grips and connected to a rigid rig frame, a soft aluminium bar, and a stepper motor with forces up to 20 kN. A new three zone split electrical resistance furnace which generates a stable and uniform heat atmosphere over 200 mm length was used to heat the samples. An 8 mm diameter port at 45° to the centre of the furnace was made in order to allow the neutron beam through the furnace to illuminate the sample. The entire instrument is mounted on the positioner at ENGIN-X and has the potential ability to operate continuously while being moved in and out of the neutron diffraction beam. The performance of the rig has been demonstrated by tracking the evolution of lattice strains in type 316H stainless steel under elastic follow-up control at 550 °C.

Reduction of distortions in large aluminium parts by controlling machining-induced residual stresses

Large aluminium monolithic parts used in the aeronautic industry frequently show significant geometric distortions after the machining process. These distortions are the consequence of the initial residual stresses of the raw material as well as machining-induced residual stresses. Therefore, to minimise distortions, it is fundamental to understand the effect of the different parameters of the manufacturing process and define the optimum manufacturing strategy. This work studies the effect of initial residual stresses of aluminium plates and the residual stresses generated by the machining process on the final geometric distortions of the part. First, 7175-T7351 aluminium bars (40 mm wide × 38 mm thick × 400 mm long) were face milled at two different cutting conditions reducing the thickness to 6 mm. The distortions were measured in a coordinate measuring machine. The results revealed that the machining strategy significantly influenced the distortions, as a difference of 65% on distortions was found between the two cutting conditions. In addition, an FEM model to predict distortions was developed. This model considers initial residual stresses (measured by the contour method) and residual stresses induced by the machining process (measured by the hole drilling technique). Once the FEM model was validated, the study was extended to more complex geometries. These new studies revealed that final distortions are sensitive to machining-induced residual stresses. Furthermore, this finding indicates that it is possible to define machining conditions which generate desirable residual stress profiles to minimise part distortion.

A Comparative Study of Impedance Measurement Techniques for Structural Health Monitoring Applications

Structural health monitoring (SHM) systems are scientifically and economically relevant as methods of detecting structural damage to various types of structures, thus increasing safety and reducing maintenance costs. Among the various principles of damage detection, the electromechanical impedance (EMI) method is based on the electrical impedance measurement of piezoelectric transducers attached to the monitored structure. Here, the accuracy and precision of the measurement system are fundamental for the correct diagnosis of the structure. Therefore, this paper performs a comparative analysis of two impedance measurement techniques for damage detection that are typically used in commercial impedance analyzers and other alternative measurement systems: 1) transient-state measurements using a sweep excitation signal and 2) steady-state measurements using a pure sinusoidal signal for each excitation frequency. Tests were performed with resistive and capacitive loads with known values and a piezoelectric transducer fixed to an aluminum bar representing a monitored structure. The two techniques were compared based on the accuracy, precision, and time required for the measurements. The results highlight the important features of each technique that should be considered for the development of impedance-based SHM systems and the correct diagnosis of monitored structures.

ArF excimer laser debrides burns without destruction of viable tissue: A pilot study

IntroductionRecent evidence indicates that early removal of eschar by tangential debridement can promote healing. Laser debridement can be used for debridement of areas that prove challenging for debridement using tangential excision. In particular, irradiation with an ArF excimer laser ablates desiccated eschar and is self-terminating, preserving hydrated or viable tissue. MethodsThermal burns were created on the flanks of two outbred, female Yorkshire pigs using aluminum bars heated to 70°C and applied for different lengths of time. Three days after injury, burns were debrided using an ArF excimer laser (193nm). Tissue was harvested immediately after debridement and 7days after debridement (10days after burn). ResultsData from a pilot study demonstrates that ArF excimer laser irradiation removes burn eschar and promotes healing at 10days after burn. ArF excimer laser debridement is self-terminating and preserves underlying and adjacent perfused tissue. Potentially, this modality would be ideal for the complex curvilinear structures of the body.

Prediction and comparison of size of the copper and aluminium bus duct system based on ampacity and temperature variations using MATLAB

The main objective of this paper is to propose an algorithm to predict and compare the sizes of the bus bar with materials like copper and aluminum by considering the allowable ampacity and allowable temperature rise with natural and forced convection cooling arrangement. Theoretical analysis is carried out with modified size of the copper bus bar using MATLAB, to analyze the ampacity and temperature variation under the natural and forced convection mode. The algebraic equation developed from thermal model is solved using MATLAB for the determination of the allowable temperature rise and ampacity of rectangular-section bus bars of copper and aluminum and also for different sizes of bus bar. An algorithm has been developed for the analysis. Experimental observations of temperature variation in copper bus bar with standard size under natural and forced cooling mode are validated with the algebraic equation developed from thermal model is solved using MATLAB. It is concluded that bus bar dimensions are compared for the materials copper and aluminum to predict the suitable equivalent dimensions for the same ampacity level and within the allowable temperature rise to reduce the cost of panel.

Testing of Auxetic Materials Using Hopkinson Bar and Digital Image Correlation

In this paper, a split Hopkinson pressure bar (SHPB) was used for impact loading of an auxetic lattice (structure with negative Poisson’s ratio) at a given strain-rate. High strength aluminum and polymethyl methacrylate bars instrumented with foil strain-gauges were used for compression of an additively manufactured missing-rib auxetic lattice. All experiments were observed using a high-speed camera with frame-rate set to approx. 135.000 fps. High-speed images were synchronized with the strain-gauge records. Dynamic equilibrium in the specimen was analyzed and optimized pulse-shaping was introduced in the selected experiments. Longitudinal and lateral in-plane displacements and strains were evaluated using digital image correlation (DIC) technique. DIC results were compared with results obtained from strain-gauges and were found to be in good agreement. Using DIC, it was possible to analyze in-plane strain distribution in the specimens and to evaluate strain dependent Poisson’s ratio of the auxetic structure.

On the dynamic buckling of very slender structures to self-weight

We present a mathematical and experimental study of the dynamic buckling of very slender structures due to their self-weight. Modern materials and powerful new analysis methods are leading to the design of very slender tall structures that may be prone to instability issues. Elastic stability of such structures is a problem inside the scope of the Non-Linear Dynamics Analysis Methods. An indicator of instability is when the structure’s free vibration frequency approaches null value. Two main factors affect these frequency results. First the stiffness, composed of elastic stiffness, always positive and non-zero, that diminishes rapidly with height, and the geometric stiffness, negative for compressive forces, whose absolute value grows as the structure gets taller and heavier. Second, the mass, that also grows with the height of the structures. To access this behaviour, we first present a simple one-degree-of-freedom mathematical model derived with Rayleigh’s Method, adopting a cubic polynomial as shape function. Next, comparisons are made with results of an experimental set up composed of a variable length cantilever vertical aluminium bar. These models reasonably agree with analytical close solutions available in the literature.

Protective effect of Solanum tuberosum against the breakdown of red blood cells: an experimental study in burn injury model

Introduction: Anemia is known to be an important problem in burn injury. We aimed to investigate the protective effect of Solanum tuberosum (potatoes), against abnormal breakdown of erythrocytes in burn injury.Methods: Ninety-six male (9 to 10 weeks old) Swiss Albino mice (34–40 g) were included into the study, which consisted of two phases: dose optimization phase (n = 48) and study phase (n = 48). Half of the mice were given S. tuberosum juice (study group) and the other half drinking water (control group). The optimal dosage causing minimum decline in hematocrit was as follows: 1.6 mL/kg at 0 h, 0.8 mL/kg at 24 hours, and 0.8 mL/kg at 36 hours of burn injury. The burn injury was induced with a solid 10-mm aluminum bar heated in boiling water.Results: The decrease in hematocrit level was significantly lower in the study group than the control group at 24 and 48 hours (P = 0.05 and P = 0.023, respectively). The increase in anisocytosis, a hemolytic anemia sign, was also significantly lower in the study group than the control group at 48 hours (P = 0.021). There was no significant difference between groups in terms of clotting time or the bleeding time.Conclusion: In burn injury, S. tuberosum may be beneficial against anemia and it may reduce the need for red blood cell transfusion.

The Development and Numerical Analysis of the Conical Radiator Extrusion Process

Abstract The article presents a newly developed method for single-operation extrusion of conical radiators. This is the author’s radiator manufacturing method being the subject of a patent application. The proposed method enables the manufacture of radiators either with or without an inner opening and with an integral plate. Selected results of numerical computations made within Forge®3D, a finite element method (FEM)-based software program, were presented during the analysis of the process. A comparative analysis of the proposed manufacturing method using the double-sided extrusion method was also made. The proposed manufacturing method is assumed to produce radiators in a single technological operation with the stock material being standardized 30 mm-diameter aluminium bars. The objective of the developed method is also to reduce the energy-force parameters.

A fully digital approach to replicate functional and aesthetic parameters in implant-supported full-arch rehabilitation

PurposeThe aim of this technical procedure was to use a fully digital technique (FDT) for full-arch implant support rehabilitation. The FDT was used to transfer the provisional restoration parameters to definitive restorations using intraoral scanners. MethodsThree sets of digital impressions were obtained. Through the first set, standard tessellation language 1 (STL1), provisional restorations screwed to implants and the surrounding gingival tissue was captured. STL2 consisted of intraoral scans of standardized scanbodies screwed to implants to collect 3D positioning data of implants. STL3 included the digital impression of provisional restoration out of the mouth in order to capture the gingival architecture and the peri-implant soft tissue that was not possible to transfer with the previous impressions. STL1, STL2, and STL3 were combined using computer-aided design (CAD) functions into a single file, STL4. Thus, STL4 contained information on the 3D implant positions, soft tissue architectures, occlusal relationships, correct occlusal vertical dimension and aesthetic features. Using STL4, the master models with implant analogues were 3D printed. Computer-aided design and computer-aided manufacturing milled (CAD/CAM-milled) aluminium bars and a resin prototype were produced to test the accuracy and the functional and aesthetic parameters. Titanium frameworks were digitally designed using STL4, milled using CAD/CAM, and finalized with pink resin and resin teeth. ConclusionThe FDT provided an effective fully digital protocol to capture all information for provisional full-arch implant restorations using an intraoral scanner and transfer that information to definitive restorations.

Equivalent Circuit of Piezoelectric Diaphragms for Impedance-Based Structural Health Monitoring Applications

Piezoelectric diaphragms are low-cost acoustic components commonly used in a wide variety of electronic devices, where the typical function is to generate an audible alarm. However, scientific study concerning the use of these components in advanced applications has increased in recent years because of their low cost and widespread availability in several standard sizes. Based on a growing interest in these components, we propose a basic equivalent electromechanical circuit considering a 1-D vibration assumption of piezoelectric diaphragms for structural health monitoring applications based on the electromechanical impedance (EMI) technique, which was used in this paper to assess the sensitivity of piezoelectric diaphragms to structural damage. The proposed circuit is a three-port type and is suitable for small metal structures. The sensitivities of three diaphragms of different sizes to structural damage were assessed using the proposed equivalent circuit and compared with the sensitivity of a conventional transducer commonly used in the EMI method. In addition, tests were performed on aluminum bars to experimentally validate the equivalent circuit, and the theoretical and experimental results correspond well.

Influence of object texture on grasping behaviour

When picking up objects using a pinch-grip there are often numerous places at which one could place the thumb and index finger, yet people seem to be consistent in where they place them. They grasp objects in such a manner that a line connecting the fingers would pass through or above the object's centre-of-mass (COM), presumably in order to minimize torque and therefore the required grip force. However, the required grip force does not only depend on the torque but also on the object's shape, its weight and the surface friction at the points at which it is grasped. Here we investigate whether participants adjust their grasping points if the surface near the COM is slippery while off-centre areas are not. Doing so would increase the torque but decrease the grip force that is required to prevent slipping. Participants were asked to lift polished aluminum bars, while their grasping points were recorded. The bars were oriented horizontally, with their center aligned with the participants' body midline. Two different bar lengths were used: 26cm and 13cm. One end of each bar was covered with anti-slip tape. The bars varied in the horizontal offset between the COM and the edge of this high friction area with offsets of 0, 1 and 2cm. Fully covered bars and bars without any anti-slip tape served as control conditions. We examined whether participants grasp further off-centre in the direction of the high friction area. The slipperiness of the surface affected the height of the grasping points, indicating that participants were aware of the difference in friction. Nevertheless, the influence on the primary measure of interest, the horizontal grasping location, was minimal. This shows that the judged COM largely determines how an object is grasped, with limited importance given to surface friction.

The effects of topical nitric oxide on healing of partial thickness porcine burns

BackgroundNitric oxide is a wound mediator that promotes wound healing. We hypothesized that topical application of nitric oxide would speed reepithelialization, enhance angiogenesis, and reduce scar thickness in a partial thickness porcine burn model. MethodsWhile under general anesthesia, 20 partial thickness burns were created on the backs of four female Yorkshire swine using a 2.5cm×2.5cm×7.5cm, 150-g aluminum bar, preheated to 80°C and applied for 20s. The necrotic epidermis was removed and the burns were randomized to low, medium, and high concentrations of a novel nitric-oxide (NO) releasing drug or its ointment vehicle applied 3 times weekly for 28 days. Full thickness punch biopsies were performed at 8, 11, 14 and 28 days after injury to determine percentage wound reepithelialization and scar thickness using H&E staining and blood vessel density using CD31 staining. ResultsAt day 11, the percentages (SD) wound reepithelialization were: control, 26.3 (34.6); low NO, 23.9 (36.9); medium NO, 43.3 (42.9); and high NO, 59.9 (43.6); ANOVA, P=0.02. The number of CD31 stained blood vessels at days 8 and 11 were greater in wounds treated with high dose NO vs. controls (48.1 vs. 22.9 [P<0.001] and 44.0 vs. 33.5 [P=0.05] per 1mm2 respectively). Scar thicknesses (SD) in mm at day 28 by treatment allocation were: control, 4.8 (1.2); low NO, 4.7 (1.2); medium NO, 4.3 (1.2); and high NO, 4.1 (1.0); P=0.22. ConclusionsTreatment of partial thickness porcine burns with high concentrations of topical NO resulted in earlier reepithelization and increased angiogenesis but not reduced scar thickness compared with its control vehicle in a partial thickness porcine burn model.