Volume 29, No. 3 (2023)
Articles
EFFECT OF DILUTE SOLID PHASE ON THE MAGNITUDE OF ACCELERATION TERM OF TOTAL PRESSURE DROP IN HORIZONTAL GAS PIPES
VICTOR JOSEPH AIMIKHE(*1), TIYA KRISTIANA WEST(1)
In this study, the effect of dilute solid phase on the magnitude of acceleration term of total pressure drop in horizontal gas pipes is investigated. The percentage contribution of pressure drop due to acceleration to the total pressure drop was studied at different pipe diameters, pipe lengths, solid concentrations, and solid-gas density ratios, respectively. The results showed that the contribution of pressure drop due to acceleration to the total pressure drop for gas-solid systems could generally be considered insignificant (less than 1%).
BIODEGRADABLE POLYMER COMPOSITE BASED ON POLYVINYL CHLORIDE AND WOOD WASTE. DEVELOPMENT AND CHARACTERIZATION
VLAD BARBULESCU, LAURENTIA ALEXANDRESCU(*), MIHAELA NITUICA, MIHAI GEORGESCU, MARIA SONMEZ, DANIELA-MARIA STELESCU, DANA GURAU
This work deals with the development and characterization of biodegradable polymer composites based on of polyvinyl chloride (PVC) and wood waste (WW) post-consumer waste. Wood waste resulting from wood processing into finished products is cryogenically ground to min. 500 nm, mechanically functionalized at temperature with polydimethylsiloxane (PDMS) (7%) and compounded in varying proportions (10%, 20%, 50%). The new composite is biodegradable due to the compounding with wood fibers, have low density and implicitly the products made from, a lower weight, reduced costs and recover waste. Soles for shoes will be processed by injection using these materials.
ASPECTS REGARDING THE STUDY OF HYDRAULIC AND MECHANICAL PARAMETERS OF A ”SPIDER CRANE” SYSTEM
NICUŞOR BAROIU(1*), VIOREL PĂUNOIU(1), VIRGIL GABRIEL TEODOR(1), GEORGIANA-ALEXANDRA MOROŞANU(1), RĂZVAN SEBASTIAN CRĂCIUN(1*)
Recognizing the crucial role that transport and lifting installations play in various sectors, including industry, construction, and extraction, as well as in mechanizing loading and unloading operations, and the movement of equipment or materials, special attention must be oriented to the diversification and the production of these installations by using the most advanced technologies. The paper presents some operating principles and characteristics of a lifting and transport Spider Crane installation equipment. This installation is considered a more economical and efficient alternative to traditional cranes for works where lifting requirements are below certain limits and significant height. Thus, an analysis of the hydraulic lifting system was carried out, based on the calculation of hydraulic fluid flows for the drive pumps. Also, was evaluated the specific speeds and forces of the hydraulic cylinders, a mechanical analysis of the clamping system with hook, as well as a finite element analysis of some mechanical and hydraulic components.
BETTER EFFICIENCIES OF SOLAR AIR HEATERS ACHIEVED WITH DIFFERENT AIRFLOWS - A BRIEF REVIEW -
VISARION-CATALIN IFRIM(1*), TEODOR POP(1)
The use of solar air heater systems brings with it the convenience of having hot air at discretion for heating households with quite low prices compared to the use of conventional heating sources. The researchers desire to achieve the highest thermal efficiency of these systems has led to the emergence of different ways of improvement. The present work is focused on the available literature in the field of SAH systems made with different types of air flow. The paper also presents the different designs for the realization of airflow types used by researchers for high efficiency during the years 2017-2021.
A FUZZY LOGIC MODEL FOR HUMAN DISTRESS DETECTION
DIMPLE OGUNBIYI(*1), IBRAHIM OGUNDOYIN(1), CALEB AKANBI(1)
Distress occurs when a person is in anxiety or fear. Existing research in distress detection arising from physical attacks focused mainly on the use of machine learning techniques. To extend research efforts, this study proposes an alternate approach using fuzzy logic. Parameters to describe physically triggered distress were identified and used as input to the designed fuzzy model. Experiments were carried out using random samples of data values to test the behavior of the model. In all cases, the model was able to show outcomes that are expected and achieved high accuracy.
POROUS FLY ASH-BASED GEOPOLYMER USABLE AS AN UNCONVENTIONAL CONSTRUCTION MATERIAL
BOGDAN-VALENTIN PAUNESCU(1), LUCIAN PAUNESCU(2*), ENIKO VOLCEANOV(3,4)
Geopolymer foam with thermal insulation properties was made by foaming the alumino-silicate mixture composed of fly ash and clay brick waste activated with alkaline activator (water glass and sodium hydroxide in aqueous solution). Other mixture components were expanded perlite as siliceous additive, usual fine aggregate (quartz sand), and less frequently used surfactant (olive oil). The main characteristics of the geopolymer foam were: low density, low thermal conductivity, and relatively high compressive strength. The residual materials contributed to low costs and the complete replacement of ordinary cement led to the significant reduction of CO2 emissions.
REVIEW OF MONITORING TECHNOLOGIES USED IN HYBRID PHOTOVOLTAIC SYSTEMS
POP TEODOR(1*), RADU-DUMITRU PENTIUC(1), VISARION-CATALIN IFRIM(1), CIPRIAN BEJENAR(1), PAVEL ATANASOAE(1)
In the present context, due to the increase in global energy demand and the need to reduce greenhouse gases, hybrid systems that produce electricity and heat from renewable sources have been proposed, designed and implemented. Most of the available solar energy is captured using photovoltaic systems and converted into electricity. Today's modern systems refer to combinations of photovoltaic and thermal panels (PV/T) to obtain electricity and domestic hot water, and systems consisting of photovoltaic panels with wind turbines which provides only electricity. With an optimal design, PV/T systems can provide buildings with 100% renewable electricity and heat. This is done in a more cost-effective and efficient way compared to using photovoltaic and solar thermal systems separately. The areas required to install photovoltaic systems can be reduced by using hybrid energy production systems. The introduction of a hybrid photovoltaic-wind system reduces the land area from 1.5 ha/MW to 0.4 ha/MW. Due to the influence of environmental factors affecting the functionality of hybrid systems and the need to achieve optimal performance, the development and implementation of advanced monitoring methods has become a mandatory requirement. The paper presents different methods of monitoring hybrid systems, their progress and performance.
TRIPHENYLTIN (IV) GLUTARATES: SYNTHESIS, FT-IR AND MÖSSBAUER STUDIES
MOUHAMADOU SEMBENE BOYE(1,2*), MOUHAMADOU BIRAME DIOP(2), MODOU SARR(2), AMINATA DIASSE-SARR(2), LIBASSE DIOP(2), ALAIN WATTIAUX(3)
Four new adducts catena-O,O′-glutaratotriphenylstannate, [(Me4N)2O2C(CH2)3CO2·4SnPh3Cl] (1), [(Me4N)2O2C(CH2)3CO2·3SnPh3Cl] (2), [(SnPh3)2O2C(CH2)3CO2·SnPh3Cl] (2′) and [(Cy2NH2)2O2C(CH2)3CO2·SnPh3Cl] (3), have been isolated from the reactions carried out in solution. The compounds have been characterized by FT-IR and Mössbauer spectroscopies except for 2’ whose structure is proposed on the basis of FT-IR data. Overall, the spectra studies sheew existence of several caracteristic bands such as υ (C=O), υ (CO2–), υ (Sn–O), υ (Sn–Cl), vibrations of glutarate ions, and the intense doublet showing the presence of phenyl groups. In the solid state, the suggested structures are discrete or of infinite chain. In this work, the geometry at Sn centers, trigonal bipyramidal or tetrahedral, is ascertained by the Mössbauer parameters. The glutarate ions exhibit a monodentate, tridentate or tetradentate coordination behavior towards the Sn atoms.
RESISTANCE TO COMPACTION/BALING OF RECYCLABLE CARDBOARD WASTE USING STATIONARY HORIZONTAL PRESSES
PAULA TUDOR(1), BIANCA-STEFANIA ZABAVA(1), GHEORGHE VOICU(1*), MIRCEA-BUCUR LAZEA(2*), GABRIEL-ALEXANDRU CONSTANTIN(1)
The paper presents the resistances to the formation of a bale of recyclable cardboard, in the ten stages of its formation, up to binding, as well as on each stage separately, for the pressing phase and for the expansion phase, until the start of a new cycle, including the mass variation of the bale in formation. It also presents the energy accumulated in the bale for each phase of its formation, and the total energy required for its formation. The presented data can be used both by the builders of balers for pressing and baling recyclable waste, and by their users to make the best settings.