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Number of results: 23
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Abstract

Recent outbreaks of adenovirus (FAdV) infections in poultry flocks have been determined in many countries in Europe, Asia and Australia connected with economic consequences, and loses in poultry production. To better understand the evolution and transmission of FAdV viruses, de- tailed codon usage analysis was performed for 137 recently obtained FAdV strains. A high effec- tive number of codons, and an indication the presence of low codon usage were determined. The presence of mutations, and their influence on codon usage was confirmed by a correlation be- tween nucleotide compositions at the 3rd codon positions, HVRs1-4, and ENCs. This presence indicate some influence of natural selection, and antigenic properties of examined FAdV strains.

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Authors and Affiliations

J.S. Niczyporuk
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Abstract

The study of the different engineering materials according to their mechanical and dynamic characteristics has become an area of research interest in recent years. Several studies have verified that the mechanical properties of the material are directly affected by the distribution and size of the particles that compose it. Such is the case of asphalt mixtures. For this reason, different digital tools have been developed in order to be able to detect the structural components of the elements in a precise, clear and efficient manner. In this work, a segmentation model is developed for different types of dense-graded asphalt mixtures with grain sizes from 9.5 mm to 0.0075 mm, using sieve size reconstruction of the laboratory production curve. The laboratory curve is used to validate the particles detection model that uses morphological operations for elements separation. All this with the objective of developing a versatile tool for the analysis and study of pavement structures in a non-destructive test. The results show that the model presented in this work is able to segment elements with an area greater than 0.0324 mm2 and reproduce the sieve size curves of the mixtures with a high percentage of precision.

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Authors and Affiliations

O.J. Reyes-Ortiz
M. Mejía
J.S. Useche-Castelblanco
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Abstract

In the present study, a novel PVA–g–PMA hybrid membrane was developed for application in direct methanol fuel cell (DMFC). Maleic anhydride (MA) was grafted on polyvinyl alcohol (PVA) both ionically and chemically using potassium persulfate (KPS), for the first time. ThePVA–g–PMA thus synthesized was then blended with 3–Amino–4–[3–(triethylammonium sulfonato)phenyl amino]phenylene hydrochloride. The prepared membranes were characterized by FT–IR, TGA. 0.0104 S/cm of proton conductivity was found for the membrane. The ion exchange capacity was found to be 2.175 meq/g and the water uptake capacity as 14.9%. The single-chamber fuel cell power density was higher (34.72 mW/cm2) and current density (62.11 mA/cm2) when compared to Nafion 117 membrane.
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Authors and Affiliations

Pratima Gajbhiye
1
A.K. Tiwari
2
Karan Mann
1
J.S. Kahlon
1
H. Upadhyay
3

  1. School of Chemical Engineering and Physical Sciences, Lovely Professional University, Phagwara, Punjab-144 411, India
  2. Department of Chemical Engineering, NIT Jalandhar, Punjab-144011, India
  3. School of Agriculture, Lovely Professional University, Phagwara, Punjab-144 411, India
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Abstract

Investment casting technology that utilizes lost-wax casting is one of the most-important achievements of ancient society. In Lower Silesia, Poland (Grzybiany, Legnica county), a 7-6 BC casting workshop was discovered with numerous artifacts, confirming the existence of the manufacturing process of metal ornaments using ceramic molds. The paper presents the research of molds and casts from the Bronze and Early Iron Ages. Microscopic analyses of the casting molds were performed, along with radiographic and chemical composition tests of the artifacts (the latter employing the use of the X-ray fluorescence spectroscopy method). The clustering method was used for alloy classification. The microstructure was analyzed by means of Scanning Electron Microscopy with Energy Dispersive Spectroscopy. Conclusions from the research were utilized in further experiments
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Authors and Affiliations

A. Garbacz-Klempka
J.S. Suchy
Z. Kwak
T. Tokarski
R. Klempka
T. Stolarczyk
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Abstract

Additive manufacturing (AM) is a process that joins similar or dissimilar materials into application-oriented objects in a wide range of sizes and shapes. This article presents an overview of two additive manufacturing techniques; namely Laser metal deposition (LMD) and Wire arc additive manufacturing (WAAM). In LMD, metallic powders are contained in one or more chambers, which are then channelled through deposition nozzles. A laser heats the particles to produce metallic beads, which are deposited in layers with the aid of an in-built motion system. In WAAM, a high voltage electric arc functions as the heat source, which helps with ensuring deposition of materials, while materials in wire form are used for the feedstock. This article highlights some of the strengths and challenges that are offered by both processes. As part of the authors’ original research work, ­Ti-6Al-4V, Stainless steel 316L and Al-12Si were prepared using LMD, while the WAAM technique was used to prepare two Al alloys; Al-5356 and CuAl8Ni2. Microstructural analysis will focus on similarity and differences in grains that are formed in layers. This article will also offer an overall comparison on how these samples compare with other materials that have been prepared using LMD and WAAM.

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Authors and Affiliations

R. Rumman
D.A. Lewis
J.Y. Hascoet
J.S. Quinton
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Abstract

The paper presents results of measuring thermal conductivity and heat capacity of bentonite foundry sand in temperature range ambient –

900 OC. During the experiments a technical purity Cu plate was cast into the green-sand moulds. Basing on measurements of the mould

temperature field during the solidification of the casting, the temperature relationships of the measured properties were evaluated. It was

confirmed that water vaporization strongly influences thermal conductivity of the moulding sand in the first period of the mould heating by

the poured casting.

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Authors and Affiliations

P.K. Krajewski
W.K. Krajewski
J.S. Suchy
G. Piwowarski
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Abstract

The casting workshop was discovered with numerous artifacts, confirming the existence of the manufacturing process of metal ornaments using ceramic molds and investment casting technology in Lower Silesia (Poland) in 7-6 BC. The research has yielded significant technological information about the bronze casting field, especially the alloys that were used and the artifacts that were made from them. Based on the analyses, the model alloys were experimentally reconstructed. Taking advantage of the computer-modeling method, a geometric visualization of the bronze bracelets was performed; subsequently, we simulated pouring liquid metal in the ceramic molds and observed the alloy solidification. These steps made it possible to better understand the casting processes from the perspective of the mold technology as well as the melting and casting of alloys.

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Authors and Affiliations

A. Garbacz-Klempka
J.S. Suchy
Z. Kwak
P. Długosz
T. Stolarczyk
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Abstract

The present work has the objective of studying the effect of shot peening with glass microspheres on SAE 1020 steel in its resistance to fatigue. Fatigue tests were carried out by rotary bending with load control and loading on balance in specimens with and without shot peening. A rotation speed of approximately 750 rpm (12.5 Hz) was employed in the fatigue tests. Vickers microhardness tests were performed in order to verify the surface hardening produced by shot peening with glass microspheres. Analysis of the steel surface and fatigue fractures was performed using scanning electron microscopy (SEM). Fatigue tests were performed in order to obtain S-N curves (Wöhler curves). It was observed that shot peening with glass microspheres improved the fatigue strength of the steel at high cycle.

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Authors and Affiliations

J.C. de Lacerda
ORCID: ORCID
I.R. Pereira
J.M.G. Costa
J.S. Pinto
H.F.M. Souza
M.A. Fonseca
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Abstract

In cellular networks, cells are grouped more densely around highly populated areas to provide more capacity. Antennas are pointed in accordance with local terrain and clutter to reduce signal shadows and interference. Hardware parameters are easily set during installation but difficult to change thereafter. In a dynamic environment of population migration, there is need to continuously tune network parameters to adapt the network performance. Modern mobile equipment logs network usage patterns and statistics over time. This information can be used to tune soft parameters of the network. These parameters may include frequency channel assignment or reuse, and transmitter radiation power assignment to provide more capacity on demand. The paper proposes that by combining the frequency and power assignments, further optimisation in resource allocation can be achieved over a traditional frequency assignment. The solution considers the interference, traffic intensity and use of priority flags to bias some edges. An Edge Weight Power and Frequency Assignment Algorithm is presented to solve the resource allocation problem in cellular networks. The paper also analyses the performance improvements obtained over that of the Edge Weight Frequency Assignment Algorithm. The results show that the proposed algorithm improves the performance of the Edge Weight Frequency Assignment Algorithm depending on the initial structure of the graph.

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Authors and Affiliations

O.S. Pharatlhatlhe
J.S.J. Daka
E. Gower
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Abstract

Fe-40wt% TiB2 nanocomposites were fabricated by mechanical activation and spark-plasma sintering of a powder mixture of iron boride (FeB) and titanium hydride (TiH2). The powder mixture of (FeB, TiH2) was prepared by high-energy ball milling in a planetary ball mill at 700 rpm for 3 h followed by spark-plasma sintering (SPS) at various conditions. Analysis of the change in relative sintered density and densification rate during sintering showed that a self-propagating high-temperature synthesis reaction occurs to form TiB2 from FeB and Ti. A sintered body with relative density higher than 98% was obtained after sintering at 1150°C for 5 and 15 min. The microstructural observation of sintered compacts with the use of FE-SEM and TEM revealed that ultrafine particulates with approximately 5 nm were evenly distributed in an Fe-matrix. A hardness value of 83 HRC was obtained, which is equivalent to that of conventional WC-20 Co systems.
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Authors and Affiliations

B.-W. Kim
X.-K. Huynh
J.-S. Kim
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Abstract

The paper presents the test results of molding compounds, sand casting molds and their analysis. The subject of testing was compound containing furan resins prepared according to the following recipe: matrix – regenerate 90% + fresh sand – 10%, furan resin – 1.10% by weight, hardener – 0.40% by weight. The impact of adhesive type and its quantity (Quan = 0.90, 1.1 and 1.5%) on the strength indexes of molding compound subject to densification was analyzed. The publication presents the test results: tensile strength Rm, compressive strength Rc and flexural strength Rg, as well as compound permeability as function of its density. The analysis also covers the impact of density level on mold strength and the distribution of density level along the mold height.

Based on the test results, it was found that the best method to obtain high strength molds made from compounds with chemical adhesives was to densify it by vibrating the system: match plate – molding flask – compound filling the mold. The effectiveness of this densification method depends on the amplitude and frequency of vibrations.

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Authors and Affiliations

Ł. Petrus
A. Bulanowski
J. Kołakowski
ORCID: ORCID
M. Urbanowicz
J. Sobieraj
M. Jelonek
M. Brzeżański
ORCID: ORCID
J.S. Zych
K. Janerka
ORCID: ORCID

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