Advances in Science and Technology Vol. 178

Abstract: Electro erosion is a manufacturing process designed for machining difficult-to-process materials. This paper presents the fabrication of a miniature punching die used for perforation and cutting, made from X15 steel, using electro erosion. Due to its properties, such as high hardness, complexity, and the need for protection against surface layer damage, this material cannot be processed with conventional methods. The electro erosion process ensures high quality and dimensional precision in the finished product. A digital surface roughness meter and the functional schematic of the PGI system are also discussed. Various roughness measurement techniques are presented, along with graphical representations and the bearing area curve. The paper highlights variations in parameters at four measurement points, as well as changes in the "c" coefficient. Finally, the surface roughness parameters Ra, Rq, and Rz are analyzed.

Abstract: The main purpose of this paper is to analyze the values of the temperature after turning of pure titanium and its alloy, Ti6Al4V, as function of different cutting parameters (rotational speed, feed and depth of cut). Based on an infrared thermometer measurements for dry turning, with un-coated carbide insert, graphically dependencies of temperature as function of the cutting parameters are presented for the both materials.

Abstract: In this paper a comparative study regarding the temperature in milling process for some types of aluminum alloys and an austenitic stainless steel is presented. In order to measure the temperature two methods are used, non-contact method, using an infrared thermometer and a contact method with six thermocouples installed along the workpiece. From the point of view of cutting parameters, for the both methods, different rotational speed and depth of cut were used, while feed speed was kept constant.

Abstract: This article focuses on minimizing the resistance of the blades to the air stream and improving the energy efficiency for the horizontal three-blade turbine NREL 5 MW. The study is structured on two levels: the design of a new geometric structure for the propeller blade and the development of an advanced control method, considering a range of 5–15 m/s wind speed. The research includes design and simulation with the Ashes software, using Computational Fluid Dynamics (CFD) and Blade Element Momentum (BEM) theories. The study shows that the new geometric blade profile improves aerodynamic effectiveness over that range.

Abstract: Robotic arms significantly help automate production processes, which is why they are important for Industry 4.0. Depending on production requirements, each operation is matched to a type of robotic arm, as they have specific and unique characteristics. A well-defined classification of robotic arms is fundamental to ensure proper selection, use, and maintenance according to the particular operations performed. This paper presents a classification of the main robotic arms used in logistics and production processes. It also summarizes the main research on the use of robotic arms in logistics and manufacturing.

Abstract: The paper presents a general view on the evolution of the endoscopic instrumentation as manipulators of the urinary tract. Afterwards in the years 1990s the flexible endoscopes have found their way into the bladder, ureter and kidney, revolutionizing endoscopy in urology. The urologists continue to adapt the rigid and flexible cystoscopes to modify old procedures and innovate new ones so that little or no postoperative hospitalization is required. Standard rigid cystoscopy is generally performed with the patient in the lithotomy position. A large variety of flexible and semi-rigid graspers and biopsy forceps are also available for use through the standard working post of the modern-day cystoscope. Additionally, the laser fibers can be used through a standard cystoscope. Alternatively, the instruments such as the rigid biopsy forceps and graspers are structurally incorporated into the bridge. The development of extracorporeal shock wave lithotripsy (ESWL) and the ureteroscopy revolutionized the treatment of ureteral calculi.

Abstract: The condition of a dynamic machine (equipment) can be estimated at the current level, by measuring the vibration levels. Each component of a machine produces a vibration with one or more specific frequencies. Knowing the components of the spectrum of frequencies of the global vibration, it is possible to determine which of the components of the moving assembly the problem occurred. Thus, by measuring the vibration, a multitude of defects can be detected, for a wide variety of dynamic machines. Unlike other diagnostic devices, spectrum analyzers have the widest use in the evaluation of vibrations and specific stresses on fixed structures or on rotor blades. Other experiments evaluate the natural frequencies of the rotors, the influence of the cavity of the rotor-stator interaction. Model or prototype studies establish the influence of pressure pulsations at partial load for radial axial turbines [5]. In the work, the vibrational behavior of a Kaplan hydraulic turbine with 6 rotor blades of high power (P=200MW, Dn=9.5m), was analyzed when mechanical failures (wear) appeared after several years of operation, the graphs being taken from the diagnostic system of the studied hydrogen generator.

Abstract: The paper presents the research’s made within the Alternative Propulsion Systems Electric and Hybrid Vehicles laboratory, from Automotive Engineering Research Centre, National University of Science and Technology Politehnica Bucharest-Pitesti branch in the field of hybrid mobility. Starting with 2002, electric and hybrid vehicle projects have been developed in this laboratory with the funding of National Council for Scientific Research in Higher Education and the support of Automobile Dacia, Renault Technologie Roumanie. These are based on vehicles in production on the Dacia cars. Among the hybrid concepts studied, we mention Nova EcoMatic Hybrid, Logan Eco Hybrid, Grand Sandero Hybrid Utility Vehicle, Hamster Electricway Hybrid, Grand Hamster Electricway Plug-in Hybrid, Gaster Electricway PHEV. The electric concepts studied were Logan Electra, Duster ZERO 4X4, Sandero Electron. Other projects were related to wireless charging systems in collaboration with INDAELTRAC Craiova and with a mobile station off grid powered by an alternative source inclusive photovoltaic panel.

Abstract: The paper presents aspects related to the development within the Alternative Propulsion Systems Electric and Hybrid Vehicles laboratory, from Automotive Engineering Research Centre, National University of Science and Technology Politehnica Bucharest-Pitesti branch of a new concept 4WD hybrid vehicle based on the Dacia Duster. The solution is a Plug-in system, parallel P4 type with two shafts, organized in a motorized solution E4WD (Electricway 4WD). The vehicle was built by implementing a hybrid propulsion system with electrified rear axle. This hybrid system is used for the first time on Dacia vehicle fitted with thermal power train with a 1.6 litre engine fuelled with Compressed Natural Gas (CNG) and a CVT (Continuously Variable Transmission), placed in the front of the vehicle and an electric powertrain located at the rear side of the vehicle. The traction battery is Lithium Fe Phosphate (LFP) type. The charging of the traction battery can be performed with the on-board charger by cable from a Wallbox or a public station.