Design, Manufacture and Experimental Characterization of Magnetorheological Rotary Brake Based on an Peristaltic Pump System

In this article the design and manufacture of the innovative MR rotary brake based on peristaltic pump inspired by the concept model of the pliers and the Rochester Pean forceps are presented . For the calculation and analysis of created structure comprehensive of roller, housing and pliers, simulations concerning the stress and strain are conducted to investigate the deformation and possible failure of part or assembly. Experimental tests including measurements of compression force and magnetic field were conducted to evaluate the performance of proposed designed MR rotary brake based on peristaltic pump system constituted by tube containing MR fluid and pliers with arm responsible of the movement and arm completely hold on bench vise

Location of Semi-Rigid Connection Effect On The Seismic Performance of Steel Frame Structures

In design steel frames, combining semi-rigid and rigid connections can result in better structural performance, particularly in seismic locations. In this study, the effects of semi-rigid beam-to-column connections located on the seismic performance of steel frame structures are investigated. The analysis uses six and twelve-story moment resisting steel frames (MRSF) with rigid, semi-rigid, and dual beam-column connections. These frames are designed according to the Egyptian design codes. Drain-2Dx computer program and seven earthquake ground motions are used in the non-linear dynamic analysis. The rotational stiffness of beam-to-column connections is indicated through the end fixity factors with a value equal to 0.6. The performances of these frames are evaluated through the roof drift ratio (RDR), the maximum story drift ratios (SDR), and the maximum column axial compression force (MACF). The results indicated that the quantities of fundamental periods, roof drift ratio, the story drift ratio, and the column axial compression force are related to stiffness, rigidity, and the number of semi-rigid connections in steel frames.

In Vitro Evaluation of Native Taro Boloso-I Starch as a Disintegrant in Tablet Formulations

Introduction. In drug delivery, solid dosage forms, of which tablet is the commonest, are still the leading preferences. An area of research focus in tablet drug delivery is the search for tablet excipients. This study was aimed at evaluating and optimizing native Taro Boloso-I starch as a tablet disintegrant. Methods. The response surface method with central composite design (CCD-RSM) was used for the analysis and optimization of the concentration of native Taro Boloso-I starch and compression force. Wet granulation method was used for the preparation of paracetamol tablets. The response variables considered were tablet crushing strength, friability, and disintegration time. Results and Discussion. Both the native Taro Boloso-I starch concentration and compression force had increasing effect on the tablet breaking force. The friability of the tablets was shown to decrease with increasing levels of the disintegrant concentration. On the other hand, compression force had a decreasing effect on friability in the investigated range. The disintegration time of the tablets was found to decrease with the concentration of the starch. The paracetamol tablets prepared with the optimized levels of native Taro Boloso-I starch and compression force showed tablet breaking force of 116.24 N, friability of 0.153%, disintegration time of 1.36 min, disintegration efficiency ratio of 562.3 N/(%Min), and comparative disintegration efficiency ratio of 13.6 with respect to commercial potato starch. Conclusions. The tablets exhibited improved crushing strength, friability, in vitro disintegration time, and disintegration efficiency ratio which suggest the novel applicability of the native Taro Boloso-I starch as an efficient pharmaceutical tablet disintegrant.

Effects of plate wear on bar forces and fiber properties in a mill scale LC-refiner

A set of piezo electric force sensors is implemented in a 52-inch mill-scale low consistency refiner to explore the effect of refiner plate wear on bar force sensor measurements. The sensor replaces a short length of a stator bar and measures normal and shear forces applied during the passage of each rotor bar. In previous work with this type of force sensor, force profiles for individual bar passing events (BPE) were investigated. In the work presented here, force profiles for individual BPEs are identified based on key features in the time domain force data. The individual bar force profiles are classified as single peak events which feature one peak corresponding to the fiber compression force and as dual peak events corresponding to fiber compression force and the corner force. The bar passing events are then analysed, based on dual peak ratio and time to peak of the early peak in the dual peak events. Force measurements are evaluated over the full run time of a set of refiner plates. Findings are compared with refiner plate wear measurements and discharge fiber analysis. It is shown that the decrease in the prevalence of the corner force correlates with the wear of the leading edge of the refiner bars or bar rounding of the run time of the refiner plate. This is accompanied by a decrease in plate performance which is represented by a decrease in fiber length and freeness reduction for the same refiner load.

Substantiation of the Density of the Soil Formed by a Ridge Drill Roller

A method is presented for determining the density of soil in the ridge from the simultaneous action of spherical disks and a conical roller wheel. Heuristic and technical analysis of the process of forming soil ridges by rollers made it possible to conclude with a 90 % reliability that the main factorsб which significantly affect the quality of soil ridge formation, are the angle of attack of spherical discs (α = 10°), the speed of the roller (vс = 5.4 km / h) and the compression force of its spring (Fspr. = 180 N).

Chest compression efficacy of child resuscitators

Background: Chest compression efficacy determines blood flow in cardiopulmonary resuscitation (CPR) and relies on body mechanics, so resuscitator weight matters. Individuals of insufficient weight are incapable of generating a sufficient downward chest compression force using traditional methods. Aims: This study investigated how a resuscitator's weight affects chest compression efficacy, determined the minimum weight required to perform chest compressions and, for children and adults below this minimum weight, examine alternate means to perform chest compressions. Methods: Volunteers aged 8 years and above were enrolled to perform video-recorded, music-facilitated, compression-only CPR on an audible click-confirming manikin for 2 minutes, following brief training. Subjects who failed this proceeded to alternate modalities: chest compressions by jumping on the lower sternum; and squat-bouncing (bouncing the buttocks on the chest). These methods were assessed via video review. Findings: There were 57 subjects. The 30 subjects above 40kg were all able to complete nearly 200 compressions in 2 minutes. Success rates declined in those who weighed less than 40kg. Below 30 kg, only one subject (29.9 kg weight) out of 14 could achieve 200 effective compressions. Nearly all of the 23 subjects who could not perform conventional chest compressions were able to achieve effective chest compressions using alternate methods. Conclusion: A weight below 40kg resulted in a declining ability to perform standard chest compressions effectively. For small resuscitators, the jumping and squat-bouncing methods resulted in sufficient compressions most of the time; however, chest recoil and injuries are concerns.

Effects of Section Properties on Structural Behaviour and Failure Mode of Built-Up CFS Columns

Built-up CFS column is a type of structure that can be classified as an industrialized building system. This column has been widely used in the construction industry. It has relatively lightweight, easy to fabricate and provide efficient installation, thus suitable for the construction with difficulty inaccessibility. However, the main issue that arises from the built-up CFS column is its bearing capacity. The ultimate strength and displacement of the built-up CFS column are prominently governed by its section properties such as size and thickness. Therefore, this study intends to investigate the effects of section properties on the structural behaviour and failure mode of built-up CFS columns. The built-up CFS column was modelled in the three-dimensional using WELSIM, taking into account the nonlinearities of geometry, material criterion and contact surface. It was found that the built-up CFS column attains ultimate strength of 53.33 kN to 210.6 kN and displacement around 1.33 mm to 2.98 mm. When the size and thickness of square hollow sections are increased, the ultimate strength increases simultaneously but the displacement shows a decrement trend. Under compression force, it was observed that the built-up CFS column suffers distortional and flexural buckling as well as connector and stiffener failures.

Testing the magnetoactive elastomer sample for compression with the test machine

A sample of a magnetoactive silicone composite with ferromagnetic fillers is examined on a testing machine. The dependences of the change in the values of the moduli of longitudinal elasticity on deformation are plotted for various modes of compression of the sample. The characteristics of the linear and nonlinear dynamics of changes in the moduli of longitudinal elasticity are given as a function of the magnitudes of the deformations of the material during compression. Within the limits of deformation of the sample, which is 24% of its height, the moduli of longitudinal elasticity are linear. The nonlinear nature of the change in the compression modulus occurs when the sample is deformed over 40%. When the compression ratio of the sample was up to 72%, the compression modulus increased by a factor of 9 without the action of a magnetic field and by a factor of 22 under the action of a magnetic field. The influence of the magnetic field on the growth of the compression moduli with the increase in the compression force ranges is shown. The property of the material to self-healing (“shape memory”) was established after testing in the mode of maximum compression of ultimate loads.

A Simple Solution to the Cylindrical Indentation of an Elastic Compressible Thin Layer Resting on a Rigid Substrate

In this paper, an analytical model is presented to study the contact that recedes between an elastic thin film that could be compressed and a substrate of rigidity. The surface of rigidity was formed due to cylindrical indentation. The substrate was assumed to be a rough surface without any friction. Further, the contact width of the substrate was derived, and the relationship between the compression force, compression depth, and the compression width was determined using the energy method. Finally, the obtained results were validated using finite element analysis.

Effect of Metallic Bipolar Plates Fillet Radii on Fuel Cell Performance

This paper studies the effects of compression, deformation, and the contact area in the membrane electrode assembly (MEA). The electrical impedance of fuel cell stacks due to the assembly of the metallic bipolar plates is also considered. According to decades-long fuel cell (FC) assembly experience, an increase in compression force can result in adequate contact resistance, but excessive compression may cause extra contact resistance and damage to the MEA structure. The study suggests a design for improving the performance of the FC stack by proposing different fillet radii metallic bipolar plates. It is found that the appropriate fillet radius reduces contact resistance by 13% and avoids the accumulation of compression, thereby maintaining contact resistance at adequate levels. The current design proposes a simple and effective method to minimize the dimension tolerance of single fuel cell units and support sufficient compression.