scholarly journals IMPROVEMENT OF MACHINE SAFETY DEVICES

2018 ◽  
Vol 58 (1) ◽  
pp. 17 ◽  
Author(s):  
Bohdan Matviiovych Hevko ◽  
Roman Bohdanovych Hevko ◽  
Oleksandra Mykolaivna Klendii ◽  
Mykola Vasyliovych Buriak ◽  
Yurii Volodymyrovych Dzyadykevych ◽  
...  
Keyword(s):  
Optimum Design ◽  
Test Bench ◽  
Theoretical Calculations ◽  
Experimental Investigations ◽  
Dynamic Parameters ◽  
Safety Devices ◽  
Basic Parameters ◽  
Machine Safety ◽  
Made In ◽  
New Machine

The article presents a development of new machine safety devices, which provide protection of operating elements from overload. Theoretical calculations have been made in order to determine the optimum design, kinematic and dynamic parameters of safety devices. A test bench has been developed and experimental investigations have been conducted in order to determine basic parameters of overload clutches.

scholarly journals Relative Stability of Electrical into Mechanical Conversion with BLDC Motor-Cascade Control

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 704
Author(s):  
Sylwester Sobieraj ◽  
Grzegorz Sieklucki ◽  
Józef Gromba
Keyword(s):  
Transfer Function ◽  
Relative Stability ◽  
Power Supply System ◽  
Theoretical Calculations ◽  
Electrical Energy ◽  
Cascade Control ◽  
Bldc Motor ◽  
Cascade System ◽  
Loop Transfer Function ◽  
Basic Parameters

The conversion of the electrical energy into the mechanical is usually realized by a motor, power electronics and cascade control. The relative stability (Θ-stability), i.e., the displacement of its eigenvalues of this system is analyzed for a drive with a BLDC motor. The influence of changing the basic parameters of the motor and power supply system on the drive operation is considered. 4th order closed-loop transfer-function of the cascade control is presented, where boundaries of the transfer-function coefficients are used. The cascade system which uncertainty of the resistance, inductance, flux and gain parameters is analyzed. Theoretical calculations for the cascade control, simulations and laboratory tests are included in the article.

Experimental Investigations on Aluminium Ultrasonic Welding Parameters

2014 ◽  
Vol 657 ◽  
pp. 306-310
Author(s):  
Lăcrămioara Apetrei ◽  
Vasile Rață ◽  
Ruxandra Rață ◽  
Elena Raluca Bulai
Keyword(s):  
Microstructural Analysis ◽  
Base Material ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Experimental Investigations ◽  
Welding Parameters ◽  
Material Structure ◽  
Welding Temperature ◽  
Wide Range ◽  
Made In

Research evolution timely tendencies, in the nonconventional technologies field, are: manufacture conditions optimization and complex equipments design. The increasing of ultrasonic machining use, in various technologies is due to the expanding need of a wide range materials and high quality manufacture standards in many activity fields. This paper present a experimental study made in order to analyze the welded zone material structure and welding quality. The effects of aluminium ultrasonic welding parameters such as relative energy, machining time, amplitude and working force were compared through traction tests values and microstructural analysis. Microhardness tests were, also, made in five different points, two in the base material and three in the welded zone, on each welded aluminium sample. The aluminum welding experiments were made at the National Research and Development Institute for Welding and Material Testing (ISIM) Timişoara. The ultrasonic welding temperature is lower than the aluminium melting temperature, that's so our experiments reveal that the aluminium ultrasonic welding process doesn't determine the appearance of moulding structure. In the joint we have only crystalline grains deformation, phase transformation and aluminium diffusion.

scholarly journals Analysis of the load capacity of the bolt joints of collecting electrodes with the rapper rod

2018 ◽  
Vol 46 ◽  
pp. 00004 ◽  
Author(s):  
Andrzej Nowak ◽  
Mirosław Kurz
Keyword(s):  
Discrete Model ◽  
Test Bench ◽  
Load Capacity ◽  
Measurement Data ◽  
The Other ◽  
The Impact ◽  
Impulse Force ◽  
Made In

This article presents an analysis of the load capacity of the bolt joints of collecting electrodes with the rapper rod, made in HUCK technology. A discrete model of the system of electrodes was worked out for the analysis of stresses in bolt joints, the validation of which was made on the basis of measurement data obtained on the test bench. Two variants of joining the plates of electrodes with the rapper rod were taken into account in calculations - the first one with the correct geometry in the rapper rod, the other one with an eccentric displacement of holes in the flat bars of the rapper rod. In both variants the modelled system was loaded with the impulse force corresponding to the impact of the hammer against the anvil, with the run obtained from measurements on the test bench. These models and the related calculations were performed in the ABAQUS environment. As a result of the analyses performed, recommendations were worked out intended to eliminate cases of the destruction of bolt joints closest to the anvil of the rapper rod.

On the nature of the microwave field emerging from a composite pupil

2020 ◽  
Vol 34 (24) ◽  
pp. 2050247
Author(s):  
Ilaria Cacciari ◽  
Daniela Mugnai ◽  
Anedio Ranfagni
Keyword(s):  
Wave Propagation ◽  
Stochastic Model ◽  
Radio Frequency ◽  
Delay Time ◽  
Microwave Field ◽  
Near Field ◽  
Phase Variation ◽  
Experimental Investigations ◽  
Frequency Signal ◽  
Made In

Further experimental investigations in the microwave field emerging from a composite pupil are reported in order to determine the nature of the wave propagation. The experiments consisted of delay-time measurements as a function of the distance of the detector from the pupil under test, as well as of the phase variation of a radio-frequency signal at 35 MHz that modulated the same microwave carrier at 9.33 GHz. In addition, measurements employing an admittance comparator were made in order to determine the character of the propagation impedance. All results obtained confirmed superluminal behavior in the near field, up to a distance of about 40 cm. These results were then interpreted within the framework of a stochastic model.

scholarly journals Nanoplasmon–Semiconductor Hybrid for Interface Catalysis

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 429 ◽  
Author(s):  
Jingang Wang ◽  
Naixing Feng ◽  
Ying Sun ◽  
Xijiao Mu
Keyword(s):  
Optical Properties ◽  
Metal Oxide ◽  
Noble Metal ◽  
Hybrid System ◽  
Physical Mechanism ◽  
Theoretical Calculations ◽  
Experimental Investigations ◽  
Exciton Coupling ◽  
Surface Catalysis ◽  
Metal Metal

We firstly, in this review, introduce the optical properties of plasmonic metals, and then focus on introducing the unique optical properties of the noble metal–metal-oxide hybrid system by revealing the physical mechanism of plasmon–exciton interaction, which was confirmed by theoretical calculations and experimental investigations. With this noble metal–metal-oxide hybrid system, plasmonic nanostructure–semiconductor exciton coupling interactions for interface catalysis has been analyzed in detail. This review can provide a deeper understanding of the physical mechanism of exciton–plasmon interactions in surface catalysis reactions.

Optimal Configuration Selection Through Experimental Tests on Branched Heat Exchanger With R134 Organic Fluid

2019 ◽  
Author(s):  
Roberto Capata ◽  
Alfonso Calabria
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Test Bench ◽  
Experimental Tests ◽  
Constructal Theory ◽  
Detailed Knowledge ◽  
Nusselt Numbers ◽  
Configuration Selection ◽  
Efflux Velocity ◽  
Made In

Abstract The aim of this work the analysis of compact branched heat exchangers, by measuring thermal efficiency and the pressure drop in several experimental tests. Three different heat exchanger configuration have been considered. In the first device, the constant efflux velocity, in the internal channels, was imposed. The second exchanger was realized by imposing constant the value of the Reynolds number. The last device was created according to the instructions of the constructal theory. All three exchangers are aluminum made. In addition, in order to have a more detailed knowledge of the phenomenon and to identify what are the parameters that govern heat transfer, an organic fluid has been used and tested. In our case R1234 organic fluid. It was therefore necessary to realize an appropriate test bench for the use of the organic fluid. Once realized, several tests were conducted. Finally in order to be able to indicate which configuration results the optimal one, the Prandtl and Nusselt numbers were obtained and compared.

Boundary-layer velocity profiles in a swirling convergent flow field

1972 ◽  
Vol 52 (2) ◽  
pp. 357-367 ◽  
Author(s):  
T. M. Houlihan ◽  
D. J. Hornstra
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Swirling Flow ◽  
Theoretical Calculations ◽  
Experimental Investigations ◽  
Conical Nozzle ◽  
Flow Conditions ◽  
Boundary Layer Flows ◽  
Layer Velocity ◽  
Convergent Flow

Velocity distributions within the boundary layer of a swirling flow of incompressible fluid in a convergent conical nozzle have been investigated. Theoretical calculations with boundary conditions more appropriate to physically existent situations discounted the existence of 'super-velocities’ within the boundary layer. Parallel experimental investigations demonstrated an interdependence of core and boundary-layer flows which precluded the maintenance of the flow conditions required by the analysis.

scholarly journals Concerning the Origin and Nature of Osteoblasts

1927 ◽  
Vol 21 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Arthur Keith
Keyword(s):  
Bone Formation ◽  
Bone Growth ◽  
Necessary Conditions ◽  
Experimental Investigations ◽  
Heterotopic Bone ◽  
Heterotopic Bone Formation ◽  
Skeletal System ◽  
Satisfactory Explanation ◽  
Linea Alba ◽  
Made In

Three specimens are described which illustrate the formation of true bone in laparotomy wounds of the epigastric region of the abdomen. The literature dealing with their occurrence is surveyed and it is found that the majority of instances (34 out of 36) occur n laparotomy wounds made in or near the supra-umbilical part of the linea alba. Specimens in the R.C.S. Museum are enumerated illustrating heterotopic formation of bone in organs and parts which have no direct connexion with the skeletal system. An attempt is made to explain their occurrence on the traditional conception of bone-growth, namely, that it is the work of a specialized cell normally confined to the skeletal system. It is concluded that the heterotopic formation of bone cannot be explained unless it be accepted, as is now advocated by Professor Leriche, of Strassburg, that under certain states cells of tissues other than the skeletal can become osteoblastic in nature and in action—a view supported by the results of many recent experimental investigations. The view advocated here, not a novel one, is that “new” osteoblasts arise from the capillary system—especially from buds thrown out by that system when a neighbouring substance or body has to be absorbed. Certain necessary conditions are mentioned, but it is admitted that a full and satisfactory explanation of why supra-umbilical scars are more frequently the site of heterotopic bone formation than laparotomy scars in other parts of the abdomen has not been reached.

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