bluuebunny/crossref_metadata_2025 huggingface dataset:
Flow and efficiency measurements with clamp-on ultrasonic equipment
Authors: Dhital T C , Nielsen T K
Published: August 2019

There are several efficiency measurement methods to determine the performance of hydraulic turbines under various circumstances in hydropower plants. To do this, most of the measurement methods require precise determination of discharge. Any hydropower plant with complex pipe geometry and short water inlet near discharge measurement section complicates the use of traditional measuring techniques. Clamp-on ultrasonic flowmeter (USM) can be a good alternative in this situation as it is easy to install at very low cost compared to most of the volumetric flowmeters. Clamp-on USM can be used as index testing method that provides relative values of hydraulic efficiency by measuring the discharge.

In this study, discharge measurements with a clamp-on USM were performed at three different positions away from a valve which was partially opened. The main objective was to study the repeatability of the measurements in each position.
Investigation of fluid transients in a penstock attached to a Francis turbine rig using seismic interferometry
Authors: Farstad Perkunder Magnus , Nielsen Torbjørn K. , Faudot Celine
Published: August 2019

Pressure fluctuations in hydropower plants contribute to fatigue loads. Pressure pulsations generated by a reaction turbine will create fluid transients in the attached system which can increase the load on structural parts if resonance occurs. Several factors govern transients in a pipe system where the main parameters are the length between reflection points and the propagation velocity. This paper investigates how to find the propagation velocity of pressure waves measured in the penstock at the Hydropower Laboratory at NTNU by applying techniques from seismic interferometry. A simple 1-D model has been developed using the method of characteristics to compare the experimental results to a known system. Seismic interferometry is primarily used in academic and research settings, the basic principle is to obtain the Green’s function between measured signals. The results from the experimental data and simulations are promising, but further research is needed to optimize both data acquisition and post processing.
Modeling of the separation for system the liquid - solid in the battery of hydrocyclones
Authors: Lamskova M , Filimonov M , Novikov A , Samofalova L , Pavlova S
Published: August 2019

The mathematical model of the process of separation for the liquid – solid system in the hydrocyclone battery is considered, at that the devices are equipped with replaceable pairs of inserts for varying the diameters of the inlet and outlet pipes. It is established that when assessing the overall degree of purification of the suspension in the hydrocyclone battery with the same diameter of the corpuses and replaceable diameters of the pipes, it is necessary to take into account not only the separation factor, but also the average residence time of the liquid in the separation zone. In this connection, it is proposed the parameter P, equal to the product of these indicators. In this interpretation, increase the total degree of purification of the suspension concomitantly with increase the number of hydrocyclones in the battery is consistent with the corresponding value of the parameter R.
Jamming of hand-operated riveter – the problem and solving it in process of modelling
Authors: Zaitsev V , Konovalov V , Rodionov Yu
Published: August 2019

During the exploitation of hand rivet tools, abnormal situations arise due to the jamming of the used mandrel (core) in the actuating mechanism, leading to an increase in process time. The main purpose of the article is establish of hand rivet tools teeth parameters to eliminate self-braking of the used mandrel (core) in the actuating mechanism. Parameters of the rivet tools teeth are determined by force analysis. The limit equilibrium conditions by the modeling process of rivet tool exploitation were obtained. The strength conditions are determined by force dependencies. The condition of self-braking of the used mandrel (core) in the hand rivet tool jaws is determined. As a result of numerical simulation, the recommended values of the angles of inclination of the teeth front surface of the rivet tool jaw, which are eliminate jamming of used mandrel (core) in the actuating mechanism, are obtained. The recommended values of the angles of inclination of the teeth front surface of the rivet tool jaw should not be less than 32 degrees.
Modeling of adsorption process in continuous counter current column having diffused flow structure in gaseous phase
Authors: Golovanchikov A B , Merentsov N A , Topilin M V
Published: August 2019

The authors have studied the physical and mathematical models of the continuous adsorbing apparatus having diffused flow structure in gaseous phase and ideal displacement in dispersed solid phase of the adsorbent. There have been obtained equations of the operating line and profiles of concentrations of redistributed component in gas and adsorbent particles in its layer height. The authors offer a calculation algorithm and have compared the main technological and geometrical parameters of the studied process with typical adsorption having ideal displacement flow structures in both phases.
Intelligent user interface design of application programs
Authors: Zubkova T , Tagirova L
Published: August 2019

The modern software is used in all areas of human activity. Application programs allows users to carry out the professional activity at the new, better level. The most important component of any application is the interface on which not only specialist productivity depends, but also quality of the performed work. As the contingent of modern users is very different, it is reasonable to develop the software and its interface part taking into account features of target audience. Use of elements of artificial intelligence at design of application programs will allow to consider features of training of users as much as possible. Creation of adaptive interfaces is caused by high growth rates of functionality of modern program systems, need of simplification of their operation and also to reduction of requirements to the professional level of users. In article the technique of development of the adaptive interface on the basis of individual characteristics of users and also their emotional status is described. Users were divided into five groups: the beginner, normal, confident, qualified and the administrator. Key parameters of individual users characteristics and also their possible emotional states are revealed. The automated system which can create groups based on the analysis of characteristics of users and their emotional state is developed, each group is provided by the adapted prototype of the interface of the application program.
Optimization of the work of the blank production of a machine-building enterprise with the use of simulation
Authors: Podvalny S L , Chizhov M I , Gusev P Y , Gusev K Y
Published: August 2019

The use of information technology in machine-building enterprises has become an integral part of the entire production process. An analysis of the literature has shown that the topic of optimization of blank production using modern information technologies has not been sufficiently disclosed. In this paper, it is proposed to use simulation modelling to optimize the work of blank production. The use of a genetic algorithm is proposed as an optimization algorithm. Practical testing of the proposed solution showed a good result.
Estimated transport of Equatorial Undercurrent observed at 90°E during the Indonesia Prima 2017 campaign
Authors: Siswanto  , Kusmanto E , McPhaden Michael J
Published: August 2019

Equatorial Undercurrent (EUC) plays an important role in the dynamic of the eastern Indian Ocean. EUC supplies water masses with high salinity into Indonesian waters. This article examines the EUC transport volume at 90°E across 2°S - 2°N observed on 1st – 3rd March 2017 during the Initiative on Maritime Observation and Analysis Expedition (Indonesian Prima 2017). The analysis of temperature and salinity obtained from conductivity, temperature and depth (CTD) instruments at five stations (CTD11 - CTD14) and current profiles of Shipboard Acoustic Doppler Current Profiles (SADCP) indicate the presence of high speed water column flowing the Arabian Sea High Salinity Water (ASHSW) as characterised by maximum salinity (35.15 - 35.2 PSU) in the temperature range of 18°C - 23°C. ASHSW carried by EUC from the western Indian Ocean at the upper thermocline layer had a tendency to be asymmetrically stronger to the north of the equator. The analysis shows a maximum EUC current speed of 94 cm/sec. Estimated EUC transport water masses based on the curvature area of salinity contour 35.15 and 35.2 PSU respectively result a ∼3.4 Sv and a ∼1.4 Sv, while at curvature area of salinity 35.00 - 35.10 PSU gave about ∼8.7 Sv. The total estimated EUC mass eastward transport calculated in this study is ∼13.5 Sv.
The Influence of ENSO and IOD During Mesoscale Convective Complex (MCC) to Rainfall in Indonesia
Authors: Rustiana S , Trismidianto  , Satyawardhana H
Published: August 2019

Climate phenomena that significantly affect Indonesian rainfall to be lower (positive) and higher (negative) than normal conditions are ENSO and IOD. The other phenomenon with different time scale with ENSO and IOD is MCC that rainfall until causing storms. This study was conducted to determine the influence of ENSO and IOD during MCC to rainfall in Indonesia. The data used are monthly data of rainfall, Nino3.4-IOD index, and hourly MCC data derived from T
bb
data of Himawari Satellite, year 2001-2015 observation. The study focused on 4 occurrence phenomena: Nino3.4 (+) IOD (+), Nino3.4 (-) IOD (-), Nino3.4 (+) IOD (-), and Nino3.4 (-) IOD (+) with the distribution of 3 longitude regions (90-105E, 106-125E, and 126-140E). The results showed that the distribution of rainfall during MCC were higher when the events of negative IOD compared to other events, especially in the western maritime of Sumatra until Kalimantan. While, in the Nusa Tenggara region there is no rainfall when positive Nino3.4 events due to positive ENSO influence from the Pacific Ocean. The MCC also give effect on interior cloud size and duration of life cycle when negative IOD events on 3 longitude regions. The effect includes the size of the interior of the cloud becomes larger and the duration of the life cycle is longer. Eccentricity interior is close to 1, means the contribution of MCC is high enough to Indonesian rainfall on negative IOD events.
Diurnal Rainfall Propagation Relate to Cold Surge-Cold Tongue Interaction over The Northern Coast of West Java
Authors: Yulihastin E , Hadi T W , Ningsih N S
Published: August 2019

Interaction of the diurnal cycle of rainfall systems between land and sea were investigated by hourly rainfall of 3B41RT TRMM dataset, daily SST dataset from OISST, 6- hourly wind and temperature data from NCEP-NCAR Reanalysis, during period of NDJFM 2000-2016. The results showed that the diurnal cycle of rainfall from sea to land and from land to sea randomly occurred on four combinations of CENS-CT, NCENS-CT, CENS-NCT, NCENS-NCT. Diurnal rainfall in northern coast of West Java for normal conditions without CENS-CT has two maximas, namely late afternoon and early morning rainfall. CENS-CT interaction changes the normal diurnal rainfall pattern into three diurnal rainfall systems: diurnal rainfall with propagate B pattern which is identified by the afternoon continous to morning rainfall and there is an offshore propagation from sea to land that occurred in the morning, diurnal rainfall with a nonpropagate pattern, namely morning rainfall which has increased intensity and duration while afternoon rainfall is minimum, diurnal rainfall with propagate A pattern which experienced rainfall from land to sea and there was a merger between the afternoon rainfall system over the land and the morning rainfall system over the sea.
Exploring Standardized Precipitation Index for predicting drought on rice paddies in Indonesia
Authors: Surmaini E , Susanti E , Syahputra M R , Hadi T W
Published: August 2019

Droughts have severe consequences for rice crops in Indonesia, as these occur annually and increase during El Niño phenomena. Accordingly, paddy drought assessment is necessary for developing adaptation strategies for successful crop production. We conducted a detailed assessment of paddy drought-climate indices in Indonesia. This was done by looking at the onset and trends of the Standardized Precipitation Index (SPI) in a three-month time scale (SPI-3) and exploring their relationship with paddy drought-affected areas. The Cartesian quadrant was used to illustrate the combination of SPI-3 onset and trend on the paddy drought affected area. This gave four different drought risk levels: low, moderate, high, and very high. The hit rate (HR) as the proportion of drought occurrences were correctly hindcast and percent of correct (PC) as the total number of correct hindcast divided by the total number of hindcast was used to verify the accuracy of drought effect prediction on paddy rice. The results demonstrate that the highest accuracy of paddy drought predictions occurred in the peak of dry season in July, while the accuracy of drought and non-drought occurrences (PC) was higher in the non-peak months, April through September, excluding July.
Rainfall Scenario of West Nusa Tenggara in 2040 Based on CCAM RCP 4.5
Authors: Nurlatifah A , Sipayung S B , Siswanto B
Published: August 2019

Climate change is one of the global issues with a broad impact to society. Because of its importance, there is a need to build a prediction system that can support mitigation, adaptation or prevention of climate change. West Nusa Tenggara (NTB) is an area where most of the population relies on agriculture for their livelihood so that the availability of rainwater becomes very important for daily survival. In this research, rainfall in NTB was predicted by CCAM (Conformal Cubic Atmospheric Model) model based on RCP (Recent Concentration Pathways) 4.5 scenario. Based on the verification results, the CCAM model was proven to perform fairly well in estimating rainfall in NTB in 2014-2016. This is evidenced by the high correlation coefficient between CCAM and observed rainfall data in several locations such as Kuripan, Kumbe, and Gunung Sari which reached 0.57, 0.51, and 0.51 respectively. In January 2040 places such as Bima, Sumbawa Besar and parts of Lombok Island are predicted to have a decrease in rainfall when compared to that in January 2018. The decrease ranges from 40-120 mm in one month. While in Kumbe and Kuripan, rainfall is predicted to increase, with an increase of about 0-40 mm in one month. In August 2040 rainfall is predicted to generally rise in NTB with an increase of up to 40 mm in one month.
Density optimization for the manufacturing of bark-based thermal insulation panels
Authors: Pásztory Z , Börcsök Z , Tsalagkas D
Published: August 2019

Buildings in general, consume and lose huge energy amounts through their heating and cooling systems. Thus, effective thermal insulation materials required to endow on energy shaving attainments. For this research, bark particles were used as raw materials for the manufacturing of low-density thermal insulation panels. The aim of this work was to determine the optimum density value of these panels in combination with their thermal conductivity and mechanical performance. Three panel densities, i.e. 250 kg/m3, 300 kg/m3and 350 kg/m3were used in this study. For each density, specimens for the thermal, physical (water absorption, thickness swelling) and mechanical (static bending, internal bond) assays had been analysed. As proposed by the results, the optimum conditions could be achieved at density levels of 350 kg/m3. All things considered, bark-based particleboards seem to be a very promising feedstock materials for their usage especially as interior thermal insulation panels, in the building sector.
Operation of energy wood plantation with special regard to harvesting technology and timber logistics
Authors: Czupy I , Mátyás K Szakálosné , Horváth A L , Horváth B , Beszédes S , Vágvölgyi A
Published: August 2019

One possible solution for the production of wood for energy or industrial purposes is the planting of energy wood plantations. In this type of target plantation, a large amount of dendromass can be produced in a short time. Before the afforestation the site survey is highly important. Based on the results the tree species can be chosen and the corresponding cultivation technologies can be planned. Energy plantations are generally man-made forests with fast-growing species and the rotation period is short. Therefore it is necessary to determine the method of harvesting and the corresponding machine system already at the planning phase. After harvesting the timber should be transported in a short period of time in order not to prevent the development of the next tree stand. At the transport large amount of wood chip must be moved for shorter or longer distance. Thus the applied logistic plays very important role in the whole process, by making the operation of timber utilizing power plants as profitable as possible.
Determining the vulnerability index in the context of high floods in An Giang province
Authors: Van Can Thu , Tri Doan Quang , Son Nguyen Thanh , Thu Thao Tran Thi , Hong Hoa Do Thi
Published: August 2019

The vulnerability, flood hazards, and exposure are three indicators to calculating and assessing flood risk in the Mekong Delta river. Flood risk assessments allows managers to understand the probability and implications of potential damage caused by floods. The vulnerability index is based on three criteria, including sensitivity and adaptive capacity related to the economic, social, and environmental aspects and benefits that floods bring to the Mekong Delta river. The flood events occurred in the years that the flood peak at Tan Chau was over 4 m, causing the most severe damage in this area. This paper will use the vulnerability index method which is the sum of the components including the sensitivity, resilience and benefits of floods to calculate and assess the flood vulnerability of 155 communes in 11 districts of An Giang province. The results showed that there are four communes were affected by average vulnerability and 151 communes with high vulnerability.
Impact of incorporation of volcanic ash on geopolymerization of eco-friendly geopolymer composites: A review
Authors: Luhar S , Rajamane N P , Corbu O , Luhar I
Published: August 2019

Volcanic ash is a product from an explosive type of volcanic eruptions. Fresh particles of volcanic ash are gritty, abrasive, vexatious and corrosive with huge scale dispersion. Consequently, it is the need of the hour to dispose this waste systematically to have relief from dilemmas like land fillings; climatic changes, pollution of the environment, water, and health hazards although the soil is a mineral intake. This crucially reviewed manuscript includes not merely the comprehension of the incorporation of volcanic ash to develop novel green Geopolymer composites but also to study its impact on the geopolymerization reaction kinetics and reactivity at dissimilar temperatures along with a precise account of its chemistry, mineralogy and the morphology.
Comparative study of experimental approaches to increase the availability of phytochemicals using gamma radiation
Authors: Petre A , Vamanu E
Published: August 2019

In recent years, there has been significant interest in the reduction of health risks due to diseases caused by oxidative stress. Many plants contain compounds that mitigate such decay, and there are many studies that attempt to increase the availability of these phytochemicals using gamma radiation. This paper reviews 14 such studies, in attempt to shed light on the overarching elements of the employed experimental designs. Most studies of gamma irradiated plants evaluated the total phenolic and flavonoid content, as well as the antioxidant capacity of plant extracts, while only a few evaluated the antimicrobial activity and the vitamin or mineral content. The assays used to quantify this data were rather similar however, the dosimetry and extraction methods varied greatly, according to the plant which was being studied. Among the reviewed papers, only a few found that the irradiation of plant material decreased or had no effect on the assayed parameters. The majority of studies showed significant increases, at various doses, among the assayed data.
Corrosion behavior of Ni/WC nano-structured composite layers synthesized by electrochemical method
Authors: Benea L , Simionescu N
Published: August 2019

Ni/WC nano-structured composite coatings were developed by electrodeposition method from a nickel plating electrolyte containing WC nanoparticles (diameter size of ~60 nm). The corrosion behavior of Ni/WC nano-structured composite coatings and pure Ni coating were comparatively investigated in wet conditions in the solution that simulates the primary water of Pressurized Water Reactors (PWRs). The morphology and chemical composition of the obtained coatings before was observed through scanning electron microscopy (SEM) connected to an energy dispersive X-ray system (EDX). The open circuit potential (OCP) and Electrochemical Impedance Spectroscopy (EIS) methods were used to evaluate the corrosion behavior, at room temperature. The nanohardness of pure Ni and Ni/WC nanocomposite coatings was tested by nanoindentation technique. SEM-EDX analyze proved that WC nanoparticles were successfully incorporated into Ni matrix. Presence of WC nanoparticles in the nickel matrix transforms surface morphology from regular pyramidal to irregular global and changes the crystallizations of nickel matrix to smaller and thinner crystallites. Ni/WC nanocomposite coating revealed a higher nanohardness value in comparison with pure Ni coating. The corrosion resistance of Ni/WC nanocomposite coating is higher under similar experimental conditions as compared with pure nickel layers, proving an enhancement of corrosion resistance.
Influence of different concentration of hydrogen peroxide on the corrosion behavior of Ti-6Al-4V alloy immersed in physiological solution
Authors: Ravoiu A , Simionescu N , Benea L
Published: August 2019

The materials used as implants are expected to be highly non toxic and should not cause any inflammatory or allergic reactions in the human body. The success of the biomaterials is mainly dependent on the reaction of the human body to the implant. Titanium and some of its alloys are used as biomaterials for dental and orthopedic applications. The most common grades used are commercially pure titanium and the Ti-6Al-4V alloy. Frequent utilization of titanium and titanium alloys as biomaterials due to their superior biocompatibility, and high corrosion resistance as to form a thin surface oxide layer, and good mechanical properties, as a certain elastic modulus and low density that make that these metals present a mechanical behavior close to those of bones. Strong and totally biocompatible, titanium is one of the few materials that naturally match the requirements for implantation in the human body. Hydrogen peroxide appears in the human body when an inflammation occurs. This research work aims to assess the influence of different concentrations of hydrogen peroxide on the corrosion behavior of Ti-6Al-4V alloy submerged in Hank's physiological solution. Electrochemical methods as Open Circuit Potential and Electrochemical Impedance Spectroscopy were applied for corrosion investigations. The results provide evidence that Ti-6Al-4V corrosion resistance is affected by inflammatory conditions presence in Hank solution.
Marine corrosion behavior of EH 36 steel in the Black Sea
Authors: Mardare L , Benea L
Published: August 2019

The marine environment is a very aggressive environment for metallic materials, especially for unprotected carbon steel. The steel have a low corrosion resistance in harsh corrosive environment like seawater. However, the most equipments and marine structures are made from carbon steel. The Black Sea is brackish water with low salinity. Due to higher-strength and added excellent toughness and formability, The High Strength Low Alloy (HSLA) steel EH36 is used in shipbuilding and other marine structures. This paper present a comparative investigation regarding the corrosion resistance of: i) uncoated EH36 naval steel, ii) coated EH36 naval steel with a two-component polymeric primer and iii) EH 36 naval steel coated with two-component polymeric primer modified by adding of TiO2 nanoparticles. All three surfaces of steel have been investigated in seawater collected from the Black Sea. In situ electrochemical measurements as: open circuit potential (OCP), polarization resistance (Rp), potentiodynamic polarization (PD) and cyclic voltammetry polarization (CV) were performed to monitor the corrosion process. The results show the improved corrosion resistance of polymeric coatings in marine environment compared with uncoated naval steel.
Microstructure and properties of HEA coating
Authors: Florea R M
Published: August 2019

HEA (high entropy alloy) is a new metallic alloy system which received, in the last period, an impressive role in material science field. The nomenclature of HEA is explained by the fact that the entropy suffers a major change at the mixing of the principal constituents in the alloy. This process, the changing of entropy, helps the formation of solid solution instead of chemical compounds. Thanks to their recorded symmetrical crystal structures, resistances to degradation in corrosive/oxidizing environment, high temperature phase stabilities and favourable mechanical properties, HEAs are classified as possible alternatives for high temperature resistant materials. The paper is structured in five point of interest: introduction, obtaining technologies, microstructures, properties of HEA coatings and conclusions.
Simulation of solidification process of cast-iron and aluminum materials
Authors: Mihai D , Cimpoeşu N , Manole V
Published: August 2019

Numerical analyse present a proper solution in order to investigate and quantify what is difficult to appreciate during technical processes. The simulated results are very close to those obtained experimentally fact that creates a big advantage in simulation process usage. Parameters like filling time and filling sequence, solidification time and cooling rate were evaluated for two metallic materials. Different dimensions and geometries of applicative elements influence considerably the casting behavior of a material even if the process is realized in the same conditions.
Preliminary results on microstructure profile of Cu-based shape memory alloy
Authors: Tudora C , Abrudeanu M , Stanciu S , Anghel D , Plaiaşu G , Rizea V , Ştirbu I , Cimpoeşu R , Coteaţă M
Published: August 2019

Shape memory alloys represent a perfect solution for noiselessly actuation with possibility of natural activation without extra energy consume. Copper-based shape memory alloy represent a cheap solution of classical Nitinol. After melting and heat treatment the experimental alloy was mechanically polished and chemical etched in order to highlight the alloy microstructure in hardened state. In this article results about an experimental alloy microstructure relief are presented. Scanning electron microscopy (SEM, VegaTC demo) and atomic force microscopy (AFM, Nanosurf EasyScan II) were used to analyze the profile of a shape memory alloy based on copper after the annealing heat treatment.
Effects of the chemical composition on the microstructural characteristics of Ti-Nb-Ta-Zr alloys
Authors: Tudoran S , Voiculescu I , Geantă V , Vizureanu P , Mârza Roşca I , Pătraşcu I , Gălbinaşu B M , Ciocoiu R
Published: August 2019

Among the biomedical alloys, titanium based alloys are currently the best solution for implantation as a result of their low levels of toxicity. To improve mechanical properties, a series of chemical compositions of some titanium alloys have been studied over the past 15 years, to provide elasticity values as close as possible to bone. The paper presents the main mechanical and microstructural characteristics of Ti-Nb-Ta-Zr alloys compared to other titanium brands. It was found that in the absence of heat treatments, the highest hardness values (437HV1) were obtained for the Ti15Nb7.6Ta8Zr alloy, and the lowest hardness value (259 HV1) was obtained for the Ti98.4 alloy.
Materials types and selection for carabiners manufacturing: a review
Authors: Burduhos-Nergis D P , Baciu C , Vizureanu P , Lohan N M , Bejinariu C
Published: August 2019

The carabiners are vital components of fall protection systems used in a variety of areas, such as: caving, construction, arboriculture, industry, rescue / evacuation operations etc. Therefore, these metallic links play an important role in preventing work accidents wich are related with fall from heights. During carabiners manufacturing, the material selection occupies an important place among the obtaining steps, because there are a high number of mechanical and chemical properties that must be possessed by the final product, in order to provide adequate user safety. This paper aims to present the manufacturing process and the main properties of the materials used for carabiners, as well as the specific advantages and disadvantages of each type of material.
Particularities of forming behavior for INCONEL 718 superalloy
Authors: Ghiban B , Guragata C M , Serban N
Published: August 2019

Present paper has the aim of establishing the plastic forming behaviour of the INCONEL 718 superalloy used for turbine engines. The experiments were realized in laboratory conditions, on a free falling dawn hammer, with high of free falling about H = 0.2 m, and the falling dawn mass about 71 kg. The determinations were made in the range of temperatures about 1100 – 1250°C, at every 50°C. Finally, the graphics of plastic forming versus temperature and mechanical working versus temperature were drawn. The final conclusion was that the optimum range of temperature for hot working of the INCONEL 718 alloy is 1150 ÷ 1250°C, in which the plastic forming resistance and specific hot working are optimum.
SEM/EDS analyses on shape memory alloy subjected to electrochemical corrosion
Authors: Baciu E R , Vasluianu R I , Bolat M , Bulancea B , Murariu A , Bosînceanu D G
Published: August 2019

The aim of the present paper was to investigate the modifications occurred in the Ti-based shape memory alloy subject to electrochemical corrosion in artificial saliva. By 2D and 3D microscopy and by qualitative determinations of the luminous variation we could notice the effects of electrochemical corrosion tests on the surface of the metallic material, and by EDS determinations (Line and Mapping modes) of the surface chemical composition we could determine the chemical modifications produced following the corrosion tests.
Centerline inhomogeneity of flat products
Authors: Réger M , Fábián E R , Tóth L
Published: August 2019

Defect free casting requires an excellent accordance between steel properties being cast and the technological parameters, especially from the aspect of inner quality and homogeneity of cast products. Typical serious defects of cast slabs is the centerline segregation (CLS). The centerline segregation in slabs develops in a very complicated way, the main factors influencing the CLS pattern are the macrosegregation and the shrinkage of solidifying melt in the mushy area. The centerline section of the slab can be characterized by different chemical composition compared to the average composition and it can contain shrinkage holes, discontinuities and inclusions. In the hot rolling process the complex shape of interdendritic holes will be modified depending on the strain applied. In chemical composition the difference remains and it can be identified even after the soaking period (over 1050 °C). As an example, the center part of an St52 grade hot rolled heavy plates and strips containing CLS can be characterized by a carbon content of 0,3-0,5 wt% and manganese content of 1,7-1,9 wt%. The segregation level – including the carbon content – can hardly be decreased by post heat treatment or annealing.
Advanced glass reinforced epoxy filled fly ash based geopolymer filler: preparation and characterization on piping materials
Authors: Hashim M F A , Abdullah M M A B , Sandu A V , Puskas A , Daud Y M , Zainal F F , Faris M A , Hasri  , Hartati
Published: August 2019

The preparation and characterization of glass reinforced epoxy filled with different weight percentage of geopolymers filler attained from fly ashand epoxy resins are reported limited of study. Recent glass reinforced epoxy pipe are reported exhibits relatively low mechanical properties, which limit their usage in structural applications and in oil and gas industrial. Thus, this restriction could be overcome through the formation of the addition of geopolymer fillers to improve their strength and toughness. The glass fiber was impregnated with different weight percentage and different molarity of fly ash-based geopolymer and epoxy hardener resin. Composite samples were made manually by filament winding technique and cured under room temperature. The sections perpendicular to the fibers and surfaces of the composites were analyzed by means of scanning electron microscope to estimate the adhesion between geopolymer matrices and fiber reinforcement. Relatively, wide range of geopolymer weight percentage from 10 % to 30 % at which can obtain high compressive properties, maximal values of compressive strength is 94.64 MPa and compressive modulus 2373.58 MPa for the sample with 30 % weight percentage of filler loading. These new composites materials show expressively enhanced mechanical properties if matched to straight glass reinforced epoxy pipe without any geopolymer filler. The positive mixture of synthetic method with the use of industrial by-products has acceptable fabricating novel low cost aluminosilicate binders, thanks to their suitable bondin contradiction of materials frequently used in structural application, could be used within the field of oil and gas industry.
Experimental research on reconditioning transmission axles by MAG robotic welding
Authors: Perianu I A , Binchiciu E F , Sîrbu N A , Bîrdeanu A V
Published: August 2019

The current paper presents the experimental program conducted in order to determine the welding technology for shaft bond wheels, of Cr and Ni low alloyed steel, in enhanced condition. The material that makes up the shaft bond wheel is in laminated state, with a diameter of 70 mm and a high tendency to cracks when subjected to welding. During exploitation, these axles are subjected to stress and fatigue which imposes developing materials with equal resistance as well as avoiding concentrators in the joint design. The steel transmission shafts, butt welded together, contain Fe-1.7%Cr-2%Ni type with a 0.4%C, respectively Fe-0.7%Mn-1%Cr type with 0.3%C, with hardness approx. 250HB on the shaft and 350HB on the axle. The preheating and inter-pass temperature, combined with mechanical characteristics of welded joints, that have similar resistance, was performed according to SR EN 1011-2-2004, using the help of equivalent carbon computational relations. Fractometric analysis of deficiency areas extracted from parts used in exploitation, at the beneficiary exploitation site, due to defects, highlighted “fish eye” defects, fatigue cracks, that determined choosing this welding technology, namely robotic, in protective gas environment, Corgon 18 – 82%Ar and 18%CO2, using EN ISO 16834-A G694MMn3Ni1CrMo wire with a diameter of Φ1.6 mm. Welding was performed by maintaining 150°C temperature between layers, at a welding speed of 280 mm/min, power 200±10A, wire feed speed 3.7 m/min, in protective gas, Corgon 18 with a 18.22 l/min flow. The joint was designed so it will have minimum concentration areas and assure cooling of welded zones, after the joint was completely filled. After the repair we extracted samples from the joint, in order to test the weld quality and assimilate the technology. Metallographic and compositional analysis performed on specific areas highlighted improved structures in the center of the weld – zone 2, which ensures a proper tenacity of the joint and a hard coat, at the exterior, that favors the good operation of the assembly under critical fatigue conditions. Results obtained confirm and recommend implementing the developed welding technology into industrial environment.
Application of taguchi’s design of experiments in optimization of metal assisted chemical etching process
Authors: Nordin N M , Azhari A W , Halin D S C , Hashim U , Zaidi S H
Published: August 2019

In this study, statistical analysis using Taguchi’s method was used to investigate the effects of various process parameters involved in metal assisted chemical etching (MACE) of silicon. The process parameters that include etching time and various etchant concentration were selected and visualized in Taguchi modelling. Each sample was then characterized using the field emission scanning electron microscopy (FESEM). All data was then analysed and evaluated using ANOVA and graph modelling in order to visualize the interaction of each model. Results showed that for etching rate, separation and size of Si nanowires, the predicted model is in agreement with the experimental data with R2 of 0.94, 0.99 and 0.98 respectively.
Disinfection apparatus for rice germ and packaging room
Authors: Ketkaew S
Published: August 2019

This paper presents the design and construction of disinfection apparatus for rice germ and packaging room by ripple pluse corona energy using adjust electric field intensity. Using flyback converter principle and controlling of the switching by IC#SG3526. The flyback converter is designed to operate at 20-25 kHz frequency through a DC high voltage high frequency transformer at output voltage of 1 kV to 5 kV, and at the input voltage of 24 VAC, By adapting the stainless tips between aluminium net in electrode cell set, one - hour operating yields the ozone gas (O3) generating capacity of 2.5 ppm to 5.5 ppm and at 3.7 ppm enables eliminate diseases in rice germ and packaging room. In the future can be developed apparatus in the commercial of Thailand 4.0.
Development and justification of optical device for contactless measurement of the displacements of control object surfaces
Authors: Miroshnichenko I P , Parinov I A
Published: August 2019

The results of the development and computational-experimental justification of optical device for contactless measurement of the displacements of control object surfaces by using a laser interferometer are described. The proposed device allows solving actual measurement problems by diagnosing the state of structural materials and researching the strength properties of structures in mechanical engineering, aircraft building, shipbuilding, etc.
Biotechnologies used in wastewater treatment
Authors: Moga I C , Petrescu G , Anghelache G , Pantazi A G , Doroftei B I
Published: August 2019

One of the most efficient biological wastewater treatment process is based on the biofilm carriers’ utilization, on which the microorganisms attaches to form biofilm communities. The biological technology that uses artificial mobile supports is known as the Moving Bed Biofilm Reactor (MBBR) process. To have an efficient attachment of the biomass on the carriers, hydrophilic substrates are needed. To promote biofilm formation and development, the chemical nature of the biofilm carriers should be carefully selected. Most of the biofilm carriers are made from polyethylene. This material has hydrophobic properties. The authors propose a new material with more hydrophilic properties. Talcum is combined with polyethylene resulting a more hydrophilic material. The results regarding the biofilm adhesion on the new material are presented by the authors. Also, the paper presents a laboratory installation for wastewater treatment, on which can be compared different biological treatment processes.
Technical requirements and materials used in firefighters gloves manufacturing
Authors: Arvinte C , Sandu A V , Burduhos-Nergis D D , Bernevig Sava M A , Bejinariu C
Published: August 2019

Ensuring the safety of the operational personnel involved in the intervention actions is a priority for the institutions responsible for the prevention and management of the emergency situations, that's why special attention is paid to the protective performances of the individual protective equipment used. The safety and health of rescuers depend on how the materials used in the manufacture of protective equipment for the action of risk factors behave. This paper presents the conditions that fire protection gloves have to meet, materials used in their manufacture and protective features that ensure the safety of users.
Electrical and thermal characteristics of nitinol wires for linear heat detectors
Authors: Micu C A , Ciubotariu-Ana P , Lohan M N , Mocanita C O , Dumitru M , Bejinariu C
Published: August 2019

In this work were investigated the modifications of electrical and thermal properties that occur with the phase changes (M→A) during heating a Nitinol shape memory alloy wire for using it as a linear heat detector. The investigations were made using three Nitinol wires with different diameters (1; 0.1 and 0.075 mm). For the thermal characterization we used differential scanning calorimetry (DSC Netzsch 200 Maia) using two different heating rates and for resistivity a milliohmmeter (Extech 380560) and a thermocouple. The results were analyzed from the point of sensitivity of the smart element in order to be used as heat variation detector.
Assessment of ionic and anionic surfactants effect on demineralized osteochondral tissue
Authors: Cobzac V , Vereştiuc L , Jian M , Nacu V
Published: August 2019

After demineralization the rabbit distal femoral osteochondral tissues were decellularized, separately with SDS and Triton X-100 for 24, 48 and 72 hours, at concentrations of 2%, 1% and 0.5%, respectively. The greatest DNA removal was achieved with Triton X-100 solutions. Cytotoxicity tests with CSM and chondrocytes have shown good and very good results, but a gradual decrease in cell viability related to the duration of treatment with surfactants compared to the control was registered. The same trend was observed in the cells population test after 7 days, while there was no difference at the 14th day. It was also determined that samples decellularized with SDS have a higher resistance to enzymatic degradation than the control and the decellularized tissue with Triton X-100. The swelling test and elasticity modulus measurements did not show values dependent of the surfactant nature.
Engineering of circular economy and good management of industrial material resources
Authors: Soporan V F , Lehene T R , Pădureţu S , Gabor T
Published: August 2019

The paper proposes a presentation of the mechanisms of institutionalization by which materials engineering becomes an action instrument for the circular economy. In the proposed variant, the designed actions are grouped under the following steps: analysis of the current situation and of the assimilation potential at the level of socio-economical mechanisms from the perspective of eco-responsibility; constructive establishment and functioning of the reglementation framework; innovative technological ideas and the entrepreneurial way of promoting of technical solutions; designing and ensuring finance systems, especially financial instruments. The introduction of specific elements from materials engineering stems from the fact that products and services, no matter how complex, use materials in order to ensure some functionality.
Considerations on the mechanisms for optimizing the relationship between the science and engineering of metallic materials from the perspective of the professional development at university level
Authors: Soporan V F , Lehene T R , Pădureţu S , Gabor T , Crişan M D
Published: August 2019

The paper presents a few considerations regarding the engineering training in the field of metallic materials, according to the present situation in Romania. It presents the following aspects: the issue of engineering training at the specific transition from the centralized economy to the market economy functionalities; problem-solving through personal experiences related to engineering in recent years; structuring the specificities in materials engineering; calibration of the training systems; determining the blueprint of training systems; considerations on the evolution of training systems; conclusions and assessments regarding the priorities of the structure of training in materials engineering. The general conclusion, by addressing the activities carried out within the analysis, is the necessity, at least in Romania, to respect the specifics of engineering activities and to avoid overlaps with what works at the level of “material science”. This is true for all levels of engineering training: bachelor’s degree, master’s degree, doctoral studies.
Types of geoecological research and areas of their application
Authors: Baryshev E , Shmakova K , Yakshina N
Published: August 2019

Planning for the environmental management, construction, as well as forecasting the impact of human activity on the environment, should be carried out based on the provisions of geoecology, which combines relationships in geographical, biological (ecological) and social-production systems. In this case, a systematic approach, as well as knowledge of the links between different systems, will allow us to simulate the level of human impact on the environment and calculate the optimal degree of intervention in its structure. Modern methods of geoecological studies used to assess the impact of human economic activity on the environment are considered, a comparison of geoecological mapping in Russian and foreign studies is carried out, the main stages necessary for conducting geoecological studies are indicated.
Experimental determination of the coefficient of restitution
Authors: Marin M , Vaduva C , Rusu M R , Rusu L
Published: August 2019

The aim of this study is to make an experimental determination of restitution coefficient during the clash between ball and stick in oina game. This study is made using a complex system for movement analysis named VICON, on 17 oina balls, that have different wear stages, in contact with two different sticks that have different texture. We make the measurement of cinematic parameters of specific points that are marked, on the equipment, during movement. These parameters are used for calculate, using 2 methods, the restitutions coefficients. The values of these coefficient are 0.44-0.545. This analysis allows to make a prediction of balls trajectory, based on movement measurement during clash and also help to optimization of motor performance in oina game.
Improved biofilm carriers for fungal exploitation in wastewater treatment
Authors: Moga I C , Bardi A , Di Gregorio S , Spennati F , Munz G , Batistini S , Iordache O G , Mitran C E , Petrescu G
Published: August 2019

In Moving Bed Biofilm Reactors (MBBR) the biofilm grows protected within small plastic carriers (known as biofilm carriers), which are designed with high internal surface area. The biological wastewater treatment process consists of adding biofilm carriers in aerated or anoxic tanks to support biofilm attachment and growth. Some of the authors conceived, designed and realised an improved carrier (new shape and material) for fungal biofilm development. The improved biofilm carriers were tested in laboratory conditions and good results were obtained. This new biofilm carrier will be used to treat cellulosic (tannery and papermill) wastewaters and is grafted with cellulose fibers for the self-sustainability of the fungal biomass. This will facilitate substrate adhesion, due to biochemical capabilities of the selected strains, which involve secretion of extracellular enzymes, that can break down substrate by combined action of several degradative processes, such as demethylation, oxidative cleavage of the propane side chain, cleavage of ether bonds between monomers etc.