bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavy Metals Content in Tissues of Feather back Fish (Notopterus notopterus) from the Sail River, Pekanbaru
Authors: Budijono B , Hasbi M , Sibagariang R D 
Published: January 2020

Abstract
This study aimed to determine the concentrations of heavy metals (Cd, Cr, Pb, Zn, Fe, and Cu) in gills, muscles, kidney, bone, liver, and reproductive organs of Notopterus notopterus from the Sail River. The results shown that the concentrations of heavy metals in each tissues of fish were as follow: muscles > reproductive organs > liver > kidney > gills and bone for Cd; liver > bone > kidney > muscles > reproductive organs > gills for Cr; gills > kidney > bone > muscles > liver > reproductive organs for Pb; gills > bone > reproductive organs > kidney > liver > muscles for Zn; gills > muscles > liver > kidney > reproductive organs > bone for Fe; bone > liver > kidney > muscles > gills > reproductive organs for Cu. Concentrations of Cr (95.62 mg/kg) was highest than 5 others heavy metals. The average of metal concentrations of Pb (35.62 mg/kg), Zn (88.47 mg/kg), and Fe (2.35 mg/kg) were highest in the gills. The estimated concentrations of Cd, Cr, Pb, Fe were higher and Zn, Cu were lower than the limits permitted.
Plankton Community Structure in PLTA Koto Panjang Reservoir, Kampar District, Riau Province
Authors: Sumiarsih E , Aryani N , Warningsih T , Mulyani I , Hasibuan I F 
Published: January 2020

Abstract
Koto Panjang Hydroelectric Power Plant is one of the reservoirs in Riau Province, many activities in Koto Panjang. Plankton is one of the organisms that is influenced by this condition. This study aims to determine the plankton community structure in Koto Panjang. The study was conducted on May 2019. Survey methods were used in this research. Samples were taken 3 times, once / weeks, in 3 different areas. One hundred liters of water was sieved into 125 ml using a plankton net number 25. The plankton was sampled was fixed using a Lugol solution and identified using a binocular microscope. There were 11 classes of plankton in Koto Panjang, 8 classes of phytoplankton and 3 classes for zooplankton. The value of plankton species diversity index (H’) is ranges from 4.86 to 5.35, dominant index (C) 0.03-0.05 and equitability index E 0.54-0.62. The plankton community structure in the Koto Panjang Reservoir is categorized as good.
Seakeeping Analysis of Hull Rounded Design With Multi-Chine Model on Fishing Vessel
Authors: Nurhasanah N , Santoso B. , Romadhoni R. , Nasutioni P. 
Published: January 2020

Abstract
This research is to find out the hydrodynamic characteristics of a ship, it presented in the form of the characteristics of the movements that are usually experienced by the ship when sailing. Therefore, testing the motion performance of 3 GT fishing vessels is done by calculating the ship’s response to ocean waves, following the oceans and oceanic which cause oscillation movements in 3 degrees of freedom of ship compilation in the waters of the Malacca Strait. The object of the research model is 3 GT fishing vessel with a hull shape rounded by varying the amount of chine. The Rounded model and the Chine model are analyzed using motion to find out RAO ships such as heaving, rolling and pitching. RAO size for maximum heave motion occurs at a speed of 12 knots in the direction of 135° with a RAO value of 1.60 m/m with a frequency of 3.03 rad/s, the RC-2 Ship model with a frequency of 3,015 rad / s and a RH model ship and with a critical peak value of RAO heave 1,713 m with a frequency of 3.15 rad/s, the maximum roll value occurs wave angle 90° beam sea with RAO value ship model RC-3 is at the lowest point with a critical peak value of RAO roll 6.3048 deg/m with a frequency of 2.306 rad / s, the RC-2 Ship model with a frequency of 6,3048 rad / s and a RH model ship and with a critical peak value of RAO roll 6,405 m with a frequency of 3.092 rad/s. In RAO pict movements heading angle 180° head sea, RC-3 ship model is at the lowest point with a critical peak value of RAO roll 1.35 deg/m with a frequency of 2.93 rad / s, the RC-2 Ship model with a frequency of 1,45 rad/s with a frequency of 2.936 rad/s, and a RH model ship and with a critical peak value of RAO roll 1,843 m with a frequency of 3.015 rad/s. From the results of the study it can be concluded that the RC-3 type of fish has a good performance when used at sea.
Analysis of temperature and stress-strain fields during laser beam welding of a TRIP steel
Authors: Vrtiel Š , Behúlová M 
Published: January 2020

Abstract
Transformation Induced Plasticity (TRIP) steels belong to the group of Advanced High Strength Steels (AHSS) that are characterized by good strength-strain combination and formability required for special applications in the automotive industry. The excellent combination of strength, ductility and formability of TRIP steels is achieved by a careful control of microstructure development in the process of their production. The microstructure of multiphase TRIP steels typically consists of ferrite, carbide-free bainite and metastable retained austenite, which can be transformed into martensite by plastic deformation. Upon crash, this feature allows the TRIP steels to absorb more energy, ensuring greater passenger safety. In the automotive industry, TRIP steels are mainly joined by resistance spot welding, laser or electron beam welding. Generally, the thermal cycle of a fusion welding process destroys the sophistically designed microstructure of these steels in fusion and heat-affected zones resulting in deterioration of mechanical properties of the weld joint. Negative consequences of the welding process can be eliminated using proper welding parameters. The paper deals with numerical simulation and analysis of the temperature and stress-strain fields developed during the laser beam welding of a CMnSiNb TRIP steel sheets with the thickness of 2 mm. Simulation model takes into account non-linear temperature and phase dependent material properties. The heat input during the laser beam welding is modelled using the conical volumetric heat source. The optimal welding parameters for production of butt joints of CMnSiNb TRIP steel sheets using the TruDisk 4002 disc laser with the maximum power of 2 kW are designed.
Analysis of behavior of composite material during loading tests
Authors: Mára V , Krčil J , Černý M 
Published: January 2020

Abstract
Composites are widely used as a material suitable for construction applications, but the operating conditions can lead to reduction of materials properties, damage initiation and collapse of the structure, so it is necessary to monitor condition of components and thus prevent its catastrophic failure. The unidirectional glass fiber reinforced polymer matrix composite (GFRP) was inspected with usage of non-destructive (NDT) acoustic emission during the static loading tests. The 0° test specimens were manufactured and tested under tensile and three-point flexural load for which the custom-made apparatus was used. Failure mechanisms were inspected by detailed analysis using scanning electron microscopy (SEM) to deduce the damage sequence. Tensile stress-initiated matrix cracking which induces formation of scarps, ribbons and riverlines followed by delamination and fiber failure with formation of radials. Flexural load showed cracks in matrix, delamination and typical compression regions in form of fiber microbuckling. Based on the speed of wave propagation and linear localization, damage processes were detected in form of lateral cracking, delamination and integrity loss during the tensile and flexural tests. The data obtained from mechanical testing were correlated with selected acoustic emission parameters (counts, events, amplitude and duration). Behavior of GFRP material during the tensile test can be described very well with usage of counts while the flexural test provides much less information. The evaluation of damage processes using event parameter based on the amplitude and duration proved to be problematic due to the noise interference. The Short-time Fourier transform (ST-FFT) and peak frequency was used for identification of failure modes. In case of tensile and flexural load the matrix cracking has lower frequencies while delamination and fiber failure have higher values.
Pulse measurements of small area thin film μc-Si:H/ZnO:B photodiodes
Authors: Remes Z , Stuchlik J 
Published: January 2020

Abstract
We introduce a triggered optoelectronic system operating in a pulse mode in the near infrared and visible spectral range 0.75– eV. The system measures current-voltage (I-V) characteristics in dark and under visible light illumination as well as electroluminescence (EL) spectra of small area thin film photodiodes and light emitting diodes with size below 1 mm2. The usefulness of the setup is demonstrated by measurement of optoelectronic properties of a hydrogenated microcrystalline silicon μc-Si:H)p-i-n diode deposited on a semi-transparent nanostructured ZnO:B electrode. No s-shaped I-Vcharacteristics were observed under white illumination near an open circuit voltage Uoc indicating a negligible charge accumulation near μc-Si:H/ZnO:B interface. The weak infrared EL correlates with the current density.
The effect of temperature on bacterial self-healing processes in building materials
Authors: Ryparová P , Tesárek P , Schreiberová H , Prošek Z 
Published: January 2020

Abstract
This paper is focused on the bacterial induced calcitation for the crack healing. The bacteria applied for this purpose are from group which is adapted for growth in the high pH environment as a concrete in hydration phase and their metabolic activity leads to create of calcite. In this study, three different bacteria strains (Sporosarcina pasteurii, Bacillus cohnii, Bacillus pseudofirmus) were applied and the influence of various temperatures on their microbial properties was investigated. Our previous experiment indicated that one of the applied bacterial strain in spores form (Bacillus pseudofirmus) are able to survive the temperatures in the range from -20 °C to 140 °C. The experiment described in this paper extends the previous study and determines the effect of different temperatures on the change in growth activity. In this experiment, bacterial activity was determined based on the change of absorbance in 640 nm by spectrophotometric measurements. The experiment was performed at optimal temperature (30 °C) and lower temperature (10 °C) and it used suitable broth for calcitation. The results showed that the beginning of metabolic activity was shifted by 40 to 50 hours. Only Bacillus cohnii showed different results because its metabolic activity was nearly zero at 10 °C.
Stress-strain analysis of hybrid joints using numerical simulation
Authors: Vrtiel Š , Nad’ M , Behúlová M 
Published: January 2020

Abstract
The design of joints between components of technical structures or equipment is a very important part of the design process and therefore significant attention must be paid to them. However, in certain cases, the values of the stress-strain state in a fixed joint exceed the strength limits, and it is therefore necessary to apply a combination of methods for a permanent joint, the so-called hybrid joint, which will lead to a reduction of evaluated stress-strain values. Problems of stress-strain state of hybrid permanent joints are analysed in this paper. Presented hybrid joint is formed by the combination of the pressed fit connection and fillet weld. The dimensional parameters and material properties each of type of connections are important for these hybrid joints application. Important parameters that affect the stress-strain state for this type of joint are mainly the size of the overlap of the pressed joint and also the geometric parameters of the fillet weld. In the framework of computer simulations and strength analyses are investigated the effects of different size of overlap of pressed fit joint and various design solutions of fillet weld joint on load capacity of hybrid connection under load. The results and some new knowledge resulting from these analyses are applicable in the design of similar types of joints in technical equipment and structures.
Investigations of microstructure and mechanical properties of brass alloys produced by sand casting method at different casting temperatures
Authors: Yilmaz Atay H , Uslu G , Kahmaz Y , Atay Ö 
Published: January 2020

Abstract
Brass, which is an alloy of copper and zinc, is of historical and lasting importance due to its hardness and workability. Indeed, to make this metal alloy, ancient metalworkers around the Mediterranean Sea were able to melt copper with zinc as early as 3000 B.C. Brass is stronger and harder than copper. The amount of copper varies between 55% and 95% by weight, depending on the type of brass and its intended use. It is easy to form into various shapes, it is a good conductor of heat and generally resistant to corrosion from salt water. It can be used to make pipes and tubes, weather-stripping and other architectural trim pieces, screws, radiators, musical instruments, and cartridge casings for firearms. The manufacturing process involves combining the appropriate raw materials into a molten metal, which is allowed to solidify. The shape and properties of the solidified metal are altered through series of carefully controlled operations to produce the desired brass alloy. Temperature used in the process is one of the parameter to affect the product properties. In this study, the brass alloys were produced by a sand casting method at different casting temperatures. Structural and mechanical properties were observed. Optical microscope, XRD and the SEM analysis were performed for the microstructure and phase analysis of the material. Charpy impact test and tensile test were applied to consider the mechanical properties of the samples. As a main purpose of this study, the results were evaluated and then the optimum temperature for the brass material production was determined.
Investigation of the Structure and Properties of SWCNT-Modified Epoxy Specimens
Authors: Burkov M V , Eremin A V 
Published: January 2020

Abstract
SWCNT-modified epoxy with advanced electrical properties was investigated in the paper. CFRPs have high specific strength and elastic modulus which are the most important properties for aerospace engineering. However a lack of electrical and heat conductivity makes efficient lightning strike protection and thermal de-icing complicated. In this research electric conductivity of epoxy binder for CFRP production is modified by addition of single-wall carbon nanotubes. Measurements of electrical conductivity of hardened epoxy binders are performed showing good increase of conductive properties.
Deformation Behavior under Static and Cyclic Tension of Polymer Grafts without and after Modification by RGD Peptides
Authors: Panin S V , Antonova L V , Byakov A V , Glushkova T V , Krivkina E O , Eremin A V , Silnikov V N , Barbarash L S 
Published: January 2020

Abstract
The structure, mechanical properties, and deformation behavior under static and cyclic tension of biofunctionalized biodegradable vascular grafts based on polyhydroxybutyrate/valerate and polycaprolactone were studied. It is shown that the modification gives rise to an almost twofold decrease of the elongation at break as well as the ultimate strength. It is shown that under cyclic loading the modification of grafts results in decreasing cyclic durability by more than twice. In doing so, the level of deforming stress decreases to a much lesser extent and is practically inferior to that for unmodified material. The analysis of principal strain ε1 and ε2 component distribution patterns in grafts of both types is carried out while the reason for the observed changes is discussed.
Comparative Analysis of the Polymeric Materials Deformation Behavior under Squeezed and Free Compression
Authors: Adamov A A , Kamenskikh A A , Nosov Yu O 
Published: January 2020

Abstract
The results of experimental studies of the modern antifriction polymer materials and composites based on them are presented in the work. The 6 most promising materials for use as antifriction coatings and interlayers in friction units of critical structures were selected from a set of materials: bearings, expansion joints etc. The deformation theory of elastic-plasticity for the active loading case is chosen to describe the polymer behavior model based on the experiments results in a first approximation. Compression charts are defined for the selected materials. Numerical models of constrained and free compression experiments are constructed. The series of numerical experiments established that the contact pressure level of composite materials is 25-40% lower at a single level of deformation. UHMWPE and modified PTFE under uniaxial deformed conditions state have an almost elastic behavior with weakly nonlinear hardening and in test problems their deformation behavior has small differences.
Electromagnetic Properties of Composite Materials Based on ABS Plastic with Carbon Nanotubes Obtained by the Additive Technology in the SHF and EHF Bands
Authors: Kuleshov G E , Badin A V , Gering M O 
Published: January 2020

Abstract
The results of study of the electromagnetic characteristics of polymer composite materials containing multiwall carbon nanotubes are presented. New radio filaments for 3D printing with MWCNTs have been created. Experimental samples were obtained from composite filaments by 3D printing. Also investigated is the ABS plastic brand Conductive with carbon fibers. Studies of electromagnetic characteristics were carried out in the SHF and EHF ranges. The frequency dependences of the complex permittivity for these materials are shown. The results show that ABS Conductive plastic has the best absorbing properties on microwave frequency, and composite plastics with MWCNTs of 2% or more on EHF.
Improving the Mechanical Properties of SiC-ceramics by means of Vacuum Electron-ion-plasma Alloying with Titanium
Authors: Leonov A A , Ivanov Yu F , Kalashnikov M P , Abdulmenova E V , Shugurov V V , Teresov A D 
Published: January 2020

Abstract
The investigation results of elemental and phase composition, state of defective substructure and microhardness of the surface layer of «film (Ti)/substrate (SiC-ceramics)» system (Ti film 0.5 μm thick was deposited on the surface of SiC-ceramics) subjected to treatment with an intense pulsed low-energy electron beam (15 J/cm2, 200 μs, 0.3 s−1, 20 pulses) are presented. It is shown that irradiation of the «film (Ti)/substrate (SiC-ceramics)» system with an electron beam is accompanied by the formation of multielement multiphase (SiC; TiC; Ti5Si3) surface layer having submicro- and nanocrystalline structure. Microhardness of the irradiated surface layer reaches a value of 74 GPa, that is twice the value of microhardness of SiC-ceramics (36 GPa).
Electromagnetic Properties of Hexaferrite Polymer Composite Materials
Authors: Sbrodov A V 
Published: January 2020

Abstract
In this paper the results of studies of the electromagnetic characteristics of composite radio materials based on Z-, W-, M-type barium ferrites and epoxy resin are presented. The frequency dependences of the reflection, transmission, and absorption coefficients are shown. The obtained results of the electromagnetic response are in good agreement with the published data on the frequencies of natural ferromagnetic resonance for the types of ferrites considered. Based on the obtained data, the spectra of complex dielectric and magnetic permeabilities were calculated. It has been suggested that the above changes in the complex magnetic permeability are associated with the presence of domain wall resonance in the region of 1 GHz and natural ferromagnetic resonance at higher frequencies.
Cytotoxic Effects of Granulated Hydroxyapatite with Various Particle Size Distribution
Authors: Zakharova O , Gusev A , Chuprunov K , Yudin A , Kuznetsov D 
Published: January 2020

Abstract
Hydroxyapatite-based materials show promise in such applications as reconstructive surgery, stomatology and cosmetology, they can also be used as components of toothpaste, disinfectant products and dietary supplements (DS). However, cytotoxicity of hydroxyapatite powders synthesized via various methods towards a variety of biological cells requires a thorough study.
Cytotoxicity of hydroxyapatite powder samples with spherical particles in three size ranges: 5-25 μm, 25-45 μm and 40-125 μm, synthesized by hydrothermal synthesis with further ultrasonic and spray-drying treatment, was studied on human blood cells and on gram-negative bacteria E.coli.

The examined hydroxyapatite samples have no toxic effect on human blood leukocytes (in concentration 40 mg per 1 ml H2O or normal saline) and on gram-negative bacteria E.coli. (in concentration 40 mg per 1 ml H2O or normal saline) regardless of the contact time and particle size. The obtained data demonstrate safety of the examined materials and absence of toxic effects towards the test objects. This allows us to regard the studied hydroxyapatite samples as biocompatible.
The present study results could be used to develop products and medicinal drugs based on hydroxyapatite granules synthesized by means of hydrothermal synthesis technique with further sonication and spray drying.
Effect of Parameters of Ultrasonic Shot Peening on the Physicomechanical Properties of the Surface Layer of Flat Samples
Authors: Shiryaev A A , Trofimov V N , Karmanov V V , Vindokurov D V 
Published: January 2020

Abstract
The work is devoted to the study of the influence of the parameters of ultrasonic shot peening on the physicomechanical properties of the surface layer of flat samples of 08ps steel, AMg2 and M2 alloys. The results of determination of residual stresses, microhardness are given. As a result, it was established that the processing time makes the largest contribution in the selected modes.
Research on metallurgical bonding of selective laser melted AlSi10Mg alloy
Authors: Dong Sensen , Zhang Xiaoxun , Ma Fang , Jiang Juze , Yang Wei , Lin Zhixiong , chen Chuanbo 
Published: January 2020

Abstract
The densification behavior, surface morphology and attendant microstructural characteristics of the selective laser melting (SLM) processed AlSi10Mg alloy affected by the processing parameters were systematically investigated. Increasing the laser scanning speed or hatch spacing will deteriorate the metallurgical bonding between melt pools, resulting in the increase of irregular pores. Scanning speed and hatch spacing affect the liquid metallurgical bonding of melt pools in different ways. By manipulating scanning speed, the shape of the melt pool changes, resulting in different extents of metallurgical bonding. Whereas hatch spacing influences the resultant metallurgical bonding by controlling the overlapping rate between neighboring scan tracks simply. The formations of the hierarchical microstructures which discriminated by the Si phase are elucidated. Coarse zones are formed by the instantaneous existence of extremely high ratio of thermal gradient (G) and solidification rate (R) at the melt pool boundary, where solidification microstructure grows planar. Fine zones are formed by columnar-dendritic growth of microstructure. During the solidification process, the contraction forces that generated by the trapped gas in the pores and gravity are applied to the liquid around irregular pores and, forms the porous microstructures different from that in dense areas eventually. The tensile tests reveal that the tensile properties of SLM-processed samples are significantly affected by the formation of porosity.