bluuebunny/crossref_metadata_2025_split huggingface dataset:
Durability of Fly Ash Geopolymer Hybrid Concrete in Seawater, Sulfuric Acid, and Fire Resistant – A Review
Authors: Rizaldi Niko , Abdurrahman Habib , Wijaya Miguel Felix , Wibisono Gunawan , Olivia Monita 
Published: October 2021

Abstract
Fly ash is a hazardous and toxic waste material from burning coal. However, it can be used as a material of geopolymer concrete because it contains high amounts of silica and alumina. Recent research on geopolymer concrete is still being conducted because it is part of green building material. This review aims to determine and analyzed the durability of fly ash geopolymer hybrid concrete in aggressive environments. The environment studied included seawater, sulfuric acid, and elevated temperature. OPC concrete is a high calcium material; therefore it is susceptible to aggressive environments compared with OPC concrete, geopolymer concrete contains aluminosilicate and low calcium material, which is not reactive with aggressive environment. The method used in this study is a literature review of several relevant research sources, and data were collected and analyzed. The results showed that fly ash geopolymer hybrid concrete had increase compressive strength compared to OPC concrete. In the seawater environment, the compressive strength of geopolymer concrete increases from 10%-15%. The compressive strength of geopolymer concrete also increases in a sulfuric acid environment up to 360 days of test age, and it is resistant to fire up until 800 °C. Likewise, the porosity of the geopolymer fly ash concrete decreased while the OPC concrete increased. According to the analysis and discussion results, it was resumed that fly ash geopolymer concrete is more environmentally friendly and durable than OPC concrete, especially in seawater, sulfuric acid, and post-fire environments.
Effect of opening depth of oblique weir with an opening on river bed morphology
Authors: Une H , Ohmoto T , Kuranaga K 
Published: October 2021

Abstract
In this study, we focused on the fact that an oblique weir with an opening activates the fluidity of the sediment compared with a conventional continuous fixed one and examined the removal function of the sediment deposited upstream of the weir. Experimental results showed that the weir with the opening increased the fluidity of the sediment deposited upstream of the weir and lowered the riverbed. The scouring section upstream of the weir was divided into a gradually varied flow section and a local flow section based on the bed topography. In the gradual flow section, the descent of water level and riverbed increases linearly as the opening depth increases. In addition, it was shown that the local scour shapes upstream and downstream of the weir were similar to each other as a result of normalization on the representative scale of vertical and transverse shapes. By creating the opening of the oblique weir, the magnitude of the downward flow generated near the left bank was reduced from 45% to 34% of the non-open weir.
Preliminary study of the origin of mafic mineral megacrysts in volcanic rocks in the southwestern part of Kulon Progo Mountains, Indonesia
Authors: Aryani L , Hakim F , Titisari A D , Nugraha G , Mahardika C A 
Published: October 2021

AbstractThe Bagelen district in the southwestern part of Kulon Progo Mountains has a unique aspect in the form of the occurrence of mafic mineral megacrysts in volcanic rocks. This research is conducted to determine the type, the distribution, and the origin of those megacrysts, which are abundant in pyroclastic rocks. Detailed geological mapping on an area of 4 x 4 km with a scale of 1: 25,000 and petrographic analysis were done to explain the geological aspects that led to the presence of mafic mineral megacrysts in the study area. Petrographic analysis shows that the types of mafic mineral megacryst are hornblende, clinopyroxene, and plagioclase. Their features under the microscope observation are oscillatory zoning, half oscillatory zoning, sieve, and breakdown texture. These minerals are found as single crystal fragments and also as clinopyroxene and hornblende cumulate fragments in pyroclastic breccia. Based on mineralogical composition and texture, these mafic mineral megacrysts were formed by fractional crystallization process in the form of crystal settling mechanism. These minerals were initially accumulated in the bottom of magma chamber, then carried upward by rapid magma rising in association with explosive eruption event of Mount Ijo. These minerals were then transported on the surface through the mechanism of pyroclastic flow and were deposited in the valley to form an alluvial fan morphology in the southwestern part of Kulon Progo Dome.
Assessing the undiscovered resources of uranium and thorium in Mamuju, West Sulawesi
Authors: Cakrabuana W , Ciputra R C , Syaeful H 
Published: October 2021

AbstractThe exploration of nuclear minerals in Mamuju, West Sulawesi has been started in 2013 by the Center for Nuclear Minerals Technology (CMNT) – Badan Tenaga Nuklir Nasional (BATAN). There is a strong indication of uranium (U) and thorium (Th) minerals occurrences in the location. To follow the exploration result up, a resources assessment is needed. Due to the limited early exploration data, the concept of undiscovered resources can be used. Of all resource assessment methods suggested by International Atomic Energy Agency (IAEA), Energy Research and Development Administration (ERDA) method is the most appropriate method to be applied in the Mamuju case. In this research, Pocos de Caldas, Brazil (Osamu Utsumi Mine for U reference and Morro do Ferro Area for Th reference) was selected as control area due to its similarity on the geological condition and its more-advanced exploration stage compared to Mamuju. All the parameters for the assessment can be determined with the ERDA method based on the available information of the control area.
Simulation of operating modes of the refrigerating machine and the heat pump when drying fish
Authors: Semenov A E , Andreev A I , Tsyplakov A A 
Published: October 2021

Abstract
Saving energy resources in the fishing industry is an important task. The purpose of the study is to determine rational schemes and operating modes of air conditioning systems for drying fish. The methodology for calculating the air conditioning system for drying fish and on its basis a computer program in the mathematical package MathCAD is developed. Two air conditioning schemes are considered: a scheme using an air heater and a chiller and a scheme using a chiller and a heat pump. The schemes were analyzed from the standpoint of energy indicators. The parameters of the air supplied to the drying chamber were taken for calculations on the basis of the need to maintain the parameters set by the fish processing technology. In this paper, air conditioning schemes for drying fish are considered, an analysis of the main energy costs during the operation of equipment is carried out. On the basis of calculations, the advantages and disadvantages of the systems, their energy costs for maintaining the specified technological modes are shown. The influence of temperature and flow rate of cold outdoor air and the use of heat recovery units for the exhaust air are shown. It was established that when using outside air with heat exchangers, it is possible to significantly reduce the consumption of heat energy for the technological mode in the cold season. In the absence of heat sources, the scheme with a refrigeration machine and a heat pump has an advantage. The research results were introduced at the fish enterprise of the Astrakhan region by the LLC “Technology of comfort”.
Obtaining new products in the PVC/AL joinery industry applying the TIPS method - case study
Authors: Ciubotariu V A , Radu C M , Grigoraș C C , Zichil V 
Published: October 2021

Abstract
Obtaining a new product, in the current stage, can no longer be achieved by waiting for it by chance, as it happened in the past, but by systematically, perseveringly, and scientifically looking for it. This paper is a case study on the application of a systematic methodology for generating solution concepts in the case of the PVC and AL joinery accessories industry. Considering that one of the requirements was that the new connector part should mount on several standardized profiles, by approaching the TIPS tools kit, a modular connector with superior strength characteristics (3%) and low complexity was obtained. Also, by rethinking the product, a reduction of 15% of the required material (PA type 6) was obtained, as well as a decrease by approximately 11% of the tools cost necessary for the manufacturing process. For the preliminary evaluation of the new product, finite element analysis was necessary and the SolidWorks Simulation 2019 software was used. The numerical data was compared with the experimental data provided by the beneficiary, the differences being within the limit of 3.5%. These data encourage the beneficiary to study in detail the new product from several points of view, considering the option of introduction into manufacturing.
Exhaust Gas Recirculation (EGR) valve, design and computational fluid dynamic analysis
Authors: Dumitrache C L , Hnatiuc B , Deleanu D 
Published: October 2021

Abstract
All EGR systems used on contemporary cars operate on the principle of “external” exhaust gas recirculation. A certain proportion of the engine exhaust gases is extracted and transmitted back into the fresh air-gasoline mixture by means of a control valve. Exhaust gas recirculation valve is generally controlled by a pneumatic or mechanical system designed to dose the exhaust gases in accordance with certain factors such as: engine speed; intake manifold pressure; engine temperature. This paper presents the design steps of the EGR valve using NX SIEMENS. After making the 3D model, it was imported into ANSYS where a study of the flow of fluids (flue gases CO2 and liquid coolant) was made. In this study it was considered that the valve was actuated and the exhaust gases enter the engine while they are also cooled by the liquid coolant. From the fluid flow modeling process it can be seen that the coolant does not take much of the flue gas temperature, its role being more to maintain a proper temperature of the body valve.
Metamaterial optical filter with maximal absorption coefficient
Authors: Ionescu D , Apreotesei G 
Published: October 2021

Abstract
Tunable transmission and absorption coefficients in visible and infrared range have been obtained for metamaterial filters with a structure of metal on dielectric nanocomponents. Materials were stacks of nanoconstituents placed in alternate layers, which present a maximum or a minimum of the transmission coefficient and convenient values of the absorption coefficient when the periodicity is interrupted in a controlled manner. A simulational set-up with the metamaterial sample in a channel waveguide was conceived for obtaining the S parameters at the field propagation, using the HFSS program. The plasmon dispersion at the metal / dielectric interface was taken into account for calculating the frequency dependent surface plasmon wave vector, which can be adjusted by modifying the refractive index and the electric permittivities of the constituents. Transmission coefficients have been calculated for different structure geometries. The optimal metamaterial configurations have been chosen, in function of the desired filtering effect, for a range of incident field wavelength of 600 – 900 nm. A transmission variation of about 50 … 80 % at the central frequency, in comparison with the transmission effects in the side bands has been demonstrated for the proposed metamaterial filters.
The influence of Stress Concentration Factors and SN curves in assessing the reliability of jacket marine platforms
Authors: Joavina R , Popa M , Jenaru A 
Published: October 2021

Abstract
The design of offshore structures, generally located in a hostile environment, with complex and repetitive loads, with low and difficult intervention possibilities in case of accidents, is a challenge for engineer teams, starting from the design phase and ending with that of decommissioning. In addition to the approximations generated by the structural calculation, the specification of the level of effort concentration and the relationship between effort and fatigue life are also sources of uncertainties in estimating fatigue degradation. Analysis of the sensitivity of fatigue degradation to stress concentration factors (SCF) and S-N curves is an important factor in obtaining realistic results. The paper seeks to establish the optimal yield theory that can be used to evaluate the structural response to cyclic loads associated with computational assumptions by comparing fatigue conditions due to fatigue at the nodes of a complex lattice-type marine drilling structure, to minimize assessment errors of structural reliability. A structural model of jacket marine platform with dimensional and material characteristics corresponding to Romanian marine platforms of “Gloria” type it is analysed, for which is evaluate and compared the fatigue life generated by hydrodynamic loads, using stress concentration factors given by Kellog and Kuang, SN curves: AWS-X, modified AWS-x and respectively BS-F. The results show that for the self-erecting platforms with lattice beam type, with small dimension elements, the stress concentration factors determined by Kellog are closer to reality while Kuang factors gives more covering results.
Analysis of innovative decarbonation technologies by methanation
Authors: Macarie A C , Balcu I , Sfirloaga P , Panaitescu F V , Panaitescu M , Lazaroiu G 
Published: October 2021

Abstract
Abstract:In the development process of Romania, the energy sector for 2030 contributes essentially through its influence on the quality of life, the environment, the competitiveness of the economy, as well as the climate [1]. Thus, the energy sector from Romania must become more economically efficient, less polluting, and more technologically advanced.This paper presents the analysis of innovative methanation decarbonation technologies, the following aspects were pursued: methanisation, the reactions involved and the importance of the methanisation process, methanisation technologies and methane use, decarbonisation through methanisation, the importance of catalysts in methanation processes, decarbonisation with Carbon Capture Storage (CCS), catalyst enabled processes. Behind modern methanation decarbonization technologies is a history of over 100 years based on research and development [2]. At present, methanization is in the attention of scientists, industry, and energy companies, because: fossil fuels are a finite resource that will soon be exhausted; the energy system is constantly changing, and renewable energies are playing an increasingly important role in it; increasing levels of CO2 in the atmosphere contributes to global climate change.
Energy saving for wireless sensor network in manufacturing and administrative projects via Smart Nodes
Authors: Mahawish A A 
Published: October 2021

Abstract
The cost-effectiveness of the operation of Wireless Sensor Network (WSN) in manufacturing and administrative projects can highly boost the production of lower goods and services that in turn enhance the marketing ability. The lifetime increase of the batteries by reducing energy wastage is the main challenge and hence, in the current paper, there is an attempt to save energy via transmitting packets as quickly as can be expected while avoiding congestion and drop packets. The time synchronization allows nodes to sleep and wake at the same time to avoid consuming energy. The suggested algorithm, would, successfully deliver a packet with a fairly high rate and reduce dropping packets. Besides, it manages to avoid congestion and saves energy when reduce the retransmission the dropped packets.
Parametric modelling and finite elements study for the boom of a truck crane
Authors: Muscă(Anghelache) G D , Năstac S M 
Published: October 2021

Abstract
Parametric modelling and finite elements study for the crane boom was done in Catia V5R20 software. 3D modelling was done considering the load diagram. This is the basic feature for this study because it gives us information between the main elements (lifting capacity, outreach, boom length lifting height) which define crane operation possibilities. The truck crane is installed on the standard undercarriage of a truck or specially built undercarriages, the engine that drives the undercarriage serving either just for equipment travel or also for driving the crane mechanism. When the engine on undercarriage is only for travel, the truck crane is provided with an additional auxiliary engine, exclusively intended for crane mechanisms operation. The studied boom belongs to Liebherr crane. For parametric modelling measurements on an existing model were needed. Finite elements study was done on the basis of virtual model using a specialized soft. We did a static study by which we determined the static parameters of the structure (stresses, deformations, safety coefficient), for all own rates within interest range. The next aim, using the parameters, is to build the static model of reaction. Any static deformation of a structure can be represented as a weighted sum of structure’s own modes, each knot can be represented as a system with only one degree of freedom. This kind of study allows us to find which is the maximum deformation, the stresses and value of safety coefficient borne by a technical system or machinery under movement or static condition.
Synchronization of Measurement Data with the Reference System
Authors: Nalepa B , Gwiazda A 
Published: October 2021

Abstract
Today, most devices are equipped with sensors that enable the collection of process data that influences the control parameters. Sensors are to replace human senses and provide information from the environment to the control algorithm. In many cases, the sensors used are subject to reference measurements from an external diagnostic system, which is to eliminate possible errors in the installation of sensors or the operation of the control algorithm. For this purpose, external systems are most often used that do not duplicate any errors from the sensors used. Most often these are vision systems that are based on the measurement of markers mounted on the tested object. The most important effect of the reference system is the verification of sensor data or the correction of the control algorithm that processes sensor data. Often, when comparing two measurement systems, there is a problem with unequal sampling rates. The main problem is comparing the two graphs as the number of data / arguments is different. In order to compare two graphs, many methods are used to reduce or extend the number of arguments. The use of data expansion or reduction methods may result in an additional error. In this article, methods of reducing measurement data from IMU sensors and encoders connected to servo motors will be presented. There is a significant difference in sampling time for the two measurement systems shown. At the beginning, the methods and applications of algorithms in the literature will be discussed. Then, the measurement data will be compared with the data processed by the algorithms. The final point of work will be the combination of the data processed by the algorithm with the measurements. Two measurements were also compared in order to estimate the measurement error and a comparative algorithm was proposed.
Research on determining the state of stress by the finite element method in rehabilitation the welded structure
Authors: Nitoi D , Babis C , Chivu O , Petriceanu S , Dimitrescu A , Tăpîrdea A I 
Published: October 2021

Abstract
The study of stress is a very important problem especially in the case of welded structures. Very often the main causes of their failure are represented by the overlap of the stresses during operation with the remaining ones during the welding process. The article presents in the first part the experimental activity that regarding the realization of some fillet welded joints remedied by two processes that aim at reducing the internal stress. In the second part of the article, starting from the experimental part presented, a model was made by the finite element method. Based on it the different states of tension resulted in the initial structure as well as in the rehabilitated ones were simulated.
A Study of a Fluid Flow in the Jet Ejector System Used in Industrial Applications
Authors: Olaru I 
Published: October 2021

Abstract
Over time, numerous studies have been carried out for jet ejectors used in refrigeration systems for various industrial applications or in solar energy recovery. These ejectors use steam or water as a working fluid because the water has a low cost, chemical stability and is safe to use. Of course, depending on the application of these ejectors in the industry, other fluids can be used. When are made the ejectors, in addition to the selection of the refrigerant, which is very important, it is taken into account, as well as its constructive design has a strong influence on its performance. In general, the compression ratio depends on the nozzle and the diffuser geometry. Compared to other systems for industrial applications, ejector systems have some advantages: simplicity in construction, high spread and low cost. However, we cannot observe that they also have a lower coefficient of performance than conventional systems, which limited the widespread application of ejector systems.
Considerations on geometric modelling and finite element analysis for a trolley travel mechanism of an overhead crane
Authors: Potîrniche M A , Căpățână G F , Muscă (Anghelache) D G 
Published: October 2021

Abstract
Overhead cranes are complex lifting machines that have one or more mechanisms by which they perform the displacements of the loads. Overhead cranes move on high-rise ways without disturbing the activity that takes place on the ground. The trolley is one of the main components of the overhead crane and houses the wheels on which the crane moves. In this paper it was realized the 3D modelling of a trolley for an overhead crane, which was based on a real example of such a displacement mechanism and was made in the Autodesk Mechanical Desktop software. Next, the paper proposed to perform an analysis of stresses and deformations in static conditions of the trolley-type displacement mechanism under the action of its own weight. Finite element analysis was performed in Algor V23 software. This software gives the user ease in modelling but at the same time offers complete and particularly powerful analysis tools. Based on some simplifying hypotheses, a relatively simple model was obtained to analyze, but which led to obtaining results that can be a starting point for specialists in the domain of designing such equipment.