JOURNAL OF ENGINEERING SCIENCE

EMPIRICAL MODELS’ APPLICABILITY FOR CALCULATING THE CENTRIFUGAL PUMP'S IMPELLERS GEOMETRIC PARAMETERS

Viorel Bostan, Andrei Petco, Ion Șaragov — Mon, 29 Jan 2024 00:00:00 +0000

This paper deals with the comparison of empirical computational models used to achieve the geometrical parameters of pumps impellers with models based on Computational Fluid Dynamics (CFD) simulations and optimization algorithms. Also, the actuality of the empirical models application in modern pump manufacturing industry is analyzed. Further, an empirical model for calculating the pump impeller geometrical parameters was presented. Applying this model, the calculation of the centrifugal pump impeller parameters for CH 6,3/20 1,1-2 canned motor pump was performed. The procedure for parameterization and generation of the geometric model based on parameters obtained from this model through ANSYS DesignModeler was also presented. CFD simulation based on ANSYS CFX was used to obtain the operating characteristic of the obtained centrifugal pump impeller. The authors carried out the comparison of the results of the designed model with the original one and with the optimized impeller obtained using optimization algorithms and CFD calculations.

COMPARISON AND EVALUATION OF CLASSICAL METHODS OF DIMENSIONAL CHAINS THEORY AND THEIR MODERN ANALOGUES

Stanislav Lealin — Mon, 29 Jan 2024 00:00:00 +0000

The requirements for the quality, reliability, and cost-effectiveness of engineering products and engineering production itself are constantly improving. As a result, there is an increasing demand for the quality of design and technological preparation of production, which includes classical dimensional analysis as its foundation. The Classical Method of dimensional analysis calculation represents a comprehensive set of computational and analytical actions carried out during the development and analysis of projects and technological processes, including: the construction of specialized dimensional diagrams for projects and technological processes, the identification and recording of interconnections between all dimensional parameters, the identification of dimensional chains, verification, and the establishment of rational sizing methods in drawings. Dimensional analysis involves a significant number of procedures and actions. The time required for dimensional analysis is substantial, ranging from 10 to 50 hours for a single technical drawing or technological process. At the same time, the use of Modern Methods for calculating dimensional chains will allow us to determine, after a thorough evaluation of manufacturing conditions at each production stage (operation), leading to a reduction in the manufacturing cost of parts. The increased workload of the evaluation process can be compensated by using databases and appropriate software that operates interactively with the user. This will also lead to a reduction in the labor intensity of dimensional analysis of projects and technological processes through automation.

TECHNOLOGICAL TRANSFER UNDER THE CONDITIONS OF DIGITALIZATION OF PRODUCTS AND PROCESSES

Vadim Iatchevici, Alexei Toca, Tatiana Nitulenco, Aurel Stroncea — Mon, 29 Jan 2024 00:00:00 +0000

Technological development is largely determined by technology transfer, which is conditioned by the absorption capacity of new technologies, and new technologies are deeply digitized technologies. Success depends on creating basic digital skills, both technical and human, developing digital infrastructure, ensuring accessibility to digital technologies. In the context of Industry 4.0 technologies, the efforts to design products with pronounced physical-cybernetic elements are important, but especially those aimed at creating digital twins, gradually moving from intermediate variants of digital model and digital shadow. Digital twin creation models refer to the life cycle with emphasis on its stages. The paper proposes a digital twin model based on the technological function, in which the modification of the properties is manifested by restructuring the internal functions of the operator, operand and interface. The central place in this model belongs to the interface, which reflects the multitude of physical-technical processes at different scales of macro, meso, micro analysis characteristic of objects and processes in machine building.

ANNEALING EFFECT ON UV DETECTION PROPERTIES OF ZnO:Al STRUCTURES

Mon, 29 Jan 2024 00:00:00 +0000

The aim of this study was to develop low-powered, highly selective UV sensor to continuously monitor personalized UV exposure as well as to study annealing effect on UV detection properties of the sensors. ZnO:Al structures were obtained by chemical growth method followed by thermal annealing at 625 °C for 2 h. The studied samples exhibit maximal UV response of 620/488 at 25 °C/50 °C to 370 nm UV radiation before/after annealing, respectively. Thermal annealing of sensor (250 °C for 1 h) led to improvement in fall time from 3860 seconds to 262 seconds at 25 °C and highest responsivity (~48 mA/W) came out for 370 nm wavelength at 75 °C operating temperatures. Consequently, excellent selectivity for 370 nm UV illumination can be ascribed as due to thermal annealing effect which increases the crystallinity, grain size, and roughness of the sensing film. The PL measurements reveals the suppression of structural defects, increase in intensity after annealing and enhanced UV response due to presence of Al content in films. Overall, these structures showed magnificent UV properties, before and especially after additional thermal annealing. UV sensing mechanism of such nanomaterial-based sensor were explained with physio-chemical processes take place on the surface of these structures. The obtained results on annealed ZnO:Al films-based devices is superior to reported performances of other nanostructures, proving new results for UV sensing applications at different operating temperatures in various fields.

EMBEDDED DEVICES AND METHODS FOR DEVELOPMENT OF SPECIAL NON-CONTACT APPLICATIONS

Sergiu Zaporojan, Eugeniu Munteanu, Vladimir Larin, Victor Pavel, Lilian Chicu — Mon, 29 Jan 2024 00:00:00 +0000

There are applications which require particular approaches for each of the used parts. The non-contact strain sensors based on microwires with positive magnetostriction requires specific technological processes starting from casting until development of the corresponding non-contact sensor device. The developed contactless sensors can be embedded into various industry critical parts which require continuous monitoring and maintenance. Hence, specific embedded devices and specific framework should be developed to provide industry reliable solution. The paper describes the technological process of casting microwires, methods of improvement casting process and stress annealing methodology used to obtain appropriate non-contact sensible elements based on microwires. Also, the paper describes the framework of using these elements in non-contact monitoring applications of the condition of specific engineering objects/structures.

THE OPTIMIZATION OF VIDEO TRANSMISSION QUALITY IN WIRELESS NETWORKS

Dinu Țurcanu, Tatiana Țurcanu — Mon, 29 Jan 2024 00:00:00 +0000

The transmission of video stream over wireless networks is used by many applications and services, from the use of equipment in home communication networks to those carrying the video surveillance stream. Numerous technical challenges may arise when the unpredictable characteristics of the radio channel align or do not align with the stipulated requirements for transmission bandwidth and the necessary latency for transporting video data. All these challenges prevent users from experiencing smooth video streaming. Depending on the application scenarios, video service emphasis may vary according of Quality of Experience - QoE or parameter used traditionally in the networks, Quality of Service - QoS. The purpose of the research consists in optimization of the flow service, which ensures the adaptability of video communication to changes of conditions over the wireless computer network. As a result of a thorough analysis of the video playback characteristics related to the wireless channel, the most optimal approach in optimizing the quality of the video stream service over a wireless LAN requiring minimal modifications was identified, and namely system centric approach.

WHERE IS ARTIFICIAL INTELLIGENCE GOING?

Titu-Marius I. Băjenescu — Mon, 29 Jan 2024 00:00:00 +0000

Artificial intelligence (AI) is the ability of a machine to mimic human functions such as reasoning, learning, planning and creativity. AI enables technical systems to perceive the environment in which they operate, process this perception and solve problems, acting to achieve a particular goal. The computer receives data (either already prepared or collected via its own sensors, such as a camera), processes it and reacts. AI systems are able to adapt their behaviour to some extent, analysing the effects of previous actions and operating autonomously.

LAND-USE AND TRANSPORT INTEGRATED PLANNING AND MODELLING IN CLUJ-NAPOCA, ROMANIA

Rodica Dorina Cadar, Rozalia Melania Boitor, Mihai Liviu Dragomir — Mon, 29 Jan 2024 00:00:00 +0000

The paper presents an example of successful reconversion of an industrial site located in the built-in area of Cluj-Napoca, Romania. This case study shows that land-use and transport integrated planning can be effectively implemented when a transport-oriented development (TOD) is designed for the redevelopment of an industrial site. Using TOD principles identified in the Romanian law and the technical criteria identified in the scientific literature, Sanex platform is analyzed to demonstrate it is a TOD. This would be the first documented TOD designed in Romania. A model is developed for TOD Sanex to estimate the impact that the redevelopment of the industrial platform into a multifunctional area will have on the local traffic. In this regard, two scenarios are analyzed – present scenario and future scenario after completion of the redevelopment. Two variants of the future scenario are discussed in connection to the Northern Mobility Corridor (CMN), the main project in implementation in the area, which is designed as a complete street. The results demonstrate that the induced traffic wouldn’t have a considerable impact on the local traffic now or in the perspective of the redevelopment. It can be integrated by the street network, which could operate in appropriate conditions. Considering the need of revitalization of the urban and rural industrial sites at the national scale in Romania and the benefits of TOD, a methodological framework in four steps is proposed. This framework would be a helpful support in the sustainable urban reconversion process, especially to achieve the reduced impact over the built environment and urban mobility.

THE USE OF VEGETABLE-DERIVED PROTEINS FOR NEW FOOD PRODUCTS

Mon, 29 Jan 2024 00:00:00 +0000

Nowadays there is a high concern with newly-identified protein sources to substitute all kinds of proteins derived from animals. The food industry faces a challenge to produce quality food products that can feed more than nine billion people by 2050, upholding the principles of a sustainable and environmentally affordable way. This idea can be supported by the use of legumes that stand out with appreciable protein content, rich in essential amino acids that increase the foaming and emulsifying properties as well as the dietary fiber content. In recent years, in order to solve environmental and social problems and to diversify food products to cover different nutritional types, proteins of plant origin are used to replace those of animal origin. The present work described a review about emerging alternative proteins for nutrition which focuses on its properties and characteristics.The work analyzes the influence of alternative proteins sources on the food products'sustainability.

WAYS OF APPLICATION OF THE CIRCULAR BIOECONOMY IN THE WINE INDUSTRY

Ana-Maria Borta, Rodica Sturza — Mon, 29 Jan 2024 00:00:00 +0000

The article reviews the conventional (composting, landspreading, tartaric acid, and grapeseed oil production) and novel ways of winemaking by-products biomass conversion with the manufacturing of value-added products to solve the disposal problem and bring extra profit to producers. Winemaking waste may be used to make biopolymers - bacterial polymers that work as a plastic alternative, and can also be utilized to make biocomposites or serve as natural fillers. It showed to be a good substrate for microorganisms for the generation of biofuels from winery waste and is the most promising, economical, and ecologically friendly option. In biotechnological applications, it can be used for the production of microbial polysaccharides, alcohols, organic acids, and enzymes, as well as single-cell protein and protein-rich fungi. The available studies indicate that it is possible to create pharmaceuticals with multiple properties of preventing or treating obesity and multiple sclerosis, atherosclerosis, diabetes, allergies, and also benefit gut microbiota. The red grape marc can be used in manufacturing encapsulated natural pigments, applicable for baked products, dairy, soft drinks, and pasta making it a feasible alternative to synthetic colorants. Considering the available opportunities, it is advised the development of industrial technologies and quality standards for the available studies introduction.

BERRY AND GRAPE METABOLITES FOR ANTIMICROBIAL APPLICATIONS AGAINST FOODBORNE BACTERIAL PATHOGENS

Daniela Cojocari, Aliona Ghendov-Mosanu, Rodica Sturza — Mon, 29 Jan 2024 00:00:00 +0000

The increase in the resistance of microorganisms to chemical substances and conventional drugs presents a serious and obvious problem worldwide, which has determined numerous researches aimed at the identification of new biocides with extended activity. Plants and their derivatives contain a wide variety of secondary metabolites that can inhibit or slow down the growth of bacteria, yeasts and molds. The microbiostatic activity of some berries represents a promising source of alternative solutions for their use in order to reduce the microbial contamination of raw materials and food products. The article elucidates the in vitro microbiostatic and microbicidal effects of some berries and grape marc rich in phenolic compounds with microorganisms that cause food spoilage: Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. The composition of the extracts is examined, and possible mechanisms of antimicrobial action are analyzed.