<abstract xmlns="http://www.w3.org/1999/xhtml">

Strict pollution norms make car’s manufacturers to promote electrical and hybrid vehicles (EVs and HEVs). Recuperation system that can capture about 8-25% of the energy is represented by the regenerative brakes, it converts losses of kinetic energy of the car during braking in form of heat to electrical or chemical energy. Regenerative brakes can provide a good increase in car’s autonomy, especially in city driving cycles with high frequency of braking. Also, they reduce friction brakes wear and offer more precisely control of wheel braking torque. A survey in this paper presents basics, uses, types and braking strategies for existing regenerative braking systems with the purpose to identify and detail their limitations. Identifying key factors that have influence on system efficiency allows to elaborate optimizing techniques, strategies and algorithms, applied to existing systems in order to develop future concepts that will overcome current limitations.
</abstract>

Survey on Regenerative Braking in Electrical and Hybrid Vehicles

<abstract xmlns="http://www.w3.org/1999/xhtml">

This paper presents a series of analyses regarding the tethered umbilical cable in uniform current cable from the composition of the underwater remotely operated vehicle (ROV). The remotely operated vehicle is used in different undersea operation when it is important to control and determine precisely the disturbance forces generated by drag due to currents that act either on the vehicle directly or indirectly on the tether umbilical cable. The dynamics of umbilical cable represent an important part in ocean environment being used for signal and power transmission application. To perform the simulation in Ansys Aqwa, two axis systems are considered. A coordinate system related to the earth, represented by the key in front of which the measurements are made and a second coordinate system related to the vehicle at a set depth relative to the surface of the key. The results obtained from the simulation show us the drag forces that are exerted on the chosen cable for a given length, drag that appear both the seaborne platforms and underwater remotely vehicle contact.
</abstract>

Constanţa Maritime University, Faculty of Navigation and Naval Transport

Study Simulation of Umbilical Cable for Underwater Vehicle

<abstract xmlns="http://www.w3.org/1999/xhtml">

The first cars with air conditioning appeared in the early 1940s. Then, 1500 Packard cars received an air conditioning system developed by Nash. In the 60s about 20% of the total production of cars had air conditioning system. Nowadays car manufacturers consider air conditioning as a standard option and try various solutions to increase thermal comfort and road safety. The air conditioning system in the current configurations is a big energy consumer system. All changes made to reduce the energy consumed will take into account temperature, humidity level, vibration and noise so that human safety and comfort are not affected. The purpose of this paper is to review the ways to reduce the energy consumed by the air conditioning system of cars and their importance.
</abstract>

“Gheorghe Asachi” Technical University of Iaşi

Solutions for Reducing the Energy Consumed by the Automotive HVAC System

<abstract xmlns="http://www.w3.org/1999/xhtml">

The scientific knowledge, transposed into the engineering practice, requires the collection, by using the most state-of-the-art and complete means of the information necessary for the decision to initiate the most appropriate measures of predictive maintenance.
In this context, the information provided as a result of the investigation of the pipelines intended for the transport of fluid hydrocarbons with smart pigging devices (cleaning, calibration, geometric, magnetic flux leakage) refers to those pre-existing in the questionnaire of the pipeline of the inspection operation. The values in the questionnaire are used to evaluate the anomalies in the inspection reports (preliminary and final).
A quantitative assessment of anomalies is based on, and limited exclusively to the results of the inspection, and does not include any numerical parameters (corrosion growth rates, anodic potential etc.), other than those from In-Line Inspection such as values Estimated Repair Factor (ERF) of anomalies.
The questionnaire (initial data provided) of the pipeline to be investigated with smart pigging devices includes at least: pipe diameter, wall thickness, pipe material, design pressure, Maximum Allowable Operating Pressure (MAOP), transported product, curve type, investigation history. The detection thresholds are applied in accordance with the manufacturing standards of the pipes.
Generally, the calculation results, namely ERF and safe pressure, based on ASME B31G (Manual for Determining the Remaining Strength of Corroded Pipelines) are used to present the pipeline condition.
There are several approaches that can be used to characterize the behavior of corrosion anomalies, both pierced and partial. ASME B31G is a very conservative criterion that helps operators avoid unnecessary cuts. It is based on an empirical adequacy to an extensive series of tests on a full scale on vessels with narrow ridges.
Depth-based histograms show the distribution of all metal loss characteristics detected along the entire length of the pipe relative to their location and surface.
The approach to the referred issue allows the collection of essential information about the pipeline, and presents summaries of any anomalies of the pipeline, having a comprehensive character.
</abstract>

Methods of Carrying Out the Anticipative Maintenance of Fluid Hydrocarbons Transport Systems

<abstract xmlns="http://www.w3.org/1999/xhtml">

Actually, the Fused Deposition Modelling is one of the most popular Additive Manufacturing technology among ordinary users because of the low-cost equipment and the great variety of materials available on the market. Even many users mostly use it, not all of them are adopting the advanced parameterisation of the processes, preferring default set-up with a small interference over the basic parameters such as layer height, number of perimeters, and infill. Regarding the nozzle diameter, several advantages and disadvantages are implied by the relation of printing time-surface finish. Usage of large-diameter nozzles present advantages such as reduced manufacturing time, low risk of clogged nozzle, and more. Those cause worse resolution for small features and support structures to be more challenging to remove. By adjusting the nozzle parameters such as extrusion width and extrusion temperature, it was possible to obtain similar effects with a regular nozzle. This research’s main goal was to investigate if there is imperative the usage of larger-diameter nozzles for speeding up the manufacturing process, or the same effect can be achieved by using nozzles with a smaller diameter. In the end, we managed to reduce the manufacturing time to half compared to the initial time.
</abstract>

Influence of Nozzle Parameters in 3D Printing Under the Manufacturing Time

AHEAD OF PRINT

Volume 69 (2023): Issue 3 (September 2023)

Volume 69 (2023): Issue 2 (June 2023)

Volume 69 (2023): Issue 1 (March 2023)

Volume 68 (2022): Issue 4 (December 2022)

Volume 68 (2022): Issue 3 (September 2022)

Volume 68 (2022): Issue 2 (June 2022)

Volume 68 (2022): Issue 1 (March 2022)

Volume 67 (2021): Issue 4 (December 2021)

Volume 67 (2021): Issue 3 (September 2021)

Volume 67 (2021): Issue 2 (June 2021)

Volume 67 (2021): Issue 1 (March 2021)

Bulletin of the Polytechnic Institute of Iași. Machine constructions Section

 Machine Construction section, as part of the Bulletin of the Polytechnic Institute of Iasi founded in 1946, appears as an autonomous publication since 1950. Currently, it is issued in both printed and electronic format, on a quarterly basis, and is included in a library exchange program with 84 other publications. The Machine Construction section is a technical scientific journal which publishes original research papers, as well as occasional reviews of treaties, lectures and monographs in various fields of Mechanical Engineering. Main topics include: theoretical and applied machine mechanics; fluid mechanics and hydro-pneumatic machines; robotics; tribology; machine manufacturing; machining technologies; industrial management; economical engineering in mechanics; machine design; mechatronics; theoretical and experimental study of strain and stress; micromechanical systems; materials machinability and surface finishing technologies; machine tools; automotive; internal combustion engines; steam and gas turbo-engines; refrigeration machines and heat pumps; renewable energy sources; heat transfer; cogeneration and tri-generation systems; applied thermodynamics and thermal systems; combustion; agricultural mechanics and machinery; technologies and equipment for food processing and food industry; bioengineering and biofuels; traffic and safety etc. At this time, there is no publication fee and full-text papers are available open-access on the university website. The review process of each submitted paper includes an anti-plagiarism test with specialized software and a double-blind independent review. The authors are notified at each stage of the process. The rejection rate is above 50%. The main publication language is English.  Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 