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Abstract

This paper addresses the problem of road safety regarding barrier placement as relative to the curb. A short summary of existing regulations is presented. Numerical simulations using the explicit finite element system Ls-Dyna are shown. In the analysis, variable distance between the barrier and the curb is assumed. The obtained result reveals that the distance has little impact on the working width of the barrier.

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Authors and Affiliations

K. Wilde
K. Jamroz
D. Burski
M. Budzyński
S. Burzyński
J. Chróścielewski
W. Witkowski
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Abstract

There is a considerable increase in the use of noise barriers in recent years. Noise barriers as a control noise solution can increase the insertion loss to protect receivers. This paper presents the results of an investigation about the acoustic efficiency of primitive root sequence diffuser (PRD) on an environmental single T-shape barrier design. A 2D boundary element method (BEM) is used to predict the insertion loss of the tested barriers. The results of rigid and with a different sequence diffuser coverage are also predicted for comparison. Employing PRD on the top surface of T-shape barrier has been found to improve the performance of barriers in comparison with the use of rigid and QRD coverage at the examined receiver locations. It has been found that decreasing the design frequency of PRD shifts the frequency effects towards lower frequencies, and therefore the overall A-weighted insertion loss is improved. It was also found that using wire mesh with reasonably efficient resistivity on the top surface of PRD improves the efficiency of the reactive barriers; however utilizing wire meshes with flow resistivity higher than the specific acoustic impedance of air on the PRD top of a diffuser barrier significantly reduces the performance of the barrier within the frequency bandwidth of the diffuser. The performance of a PRD covered T-shape barrier at 200 Hz was found to be higher than that of its equivalent QRD barriers in both the far field and in areas close to the ground. The amount of improvement compared made by PRD barrier compared with its equivalent rigid barrier at far field is about 2 to 3 dB, while this improvement relative to the barrier model "QR4" can reach up to 4-6 dB.

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Authors and Affiliations

Mohammad Monazzam
Mahdiyeh Naderzadeh
Parvin Nassiri
Samaneh Fard
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Abstract

High-temperature solid oxide fuel cells (SOFCs) are considered as suitable components of future large-scale clean and efficient power generation systems. However, at its current stage of development some technical barriers exists which limit SOFC’s potential for rapid large-scale deployment. The present article aims at providing solutions to key technical barriers in SOFC technology. The focus is on the solutions addressing thermal resistance, fuel reforming, energy conversion efficiency, materials, design, and fuel utilisation issues.

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Authors and Affiliations

Jarosław Milewski
Wojciech Budzianowski
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Abstract

An efficient system of micropropagation via somatic embryogenesis from root-derived callus was established in

Arabica coffee (Coffea arabica L.). Twenty-six callus lines were induced on MS (Murashige and Skoog, 1962)

medium supplemented with combinations of NAA (0, 0.1, 0.5, 1 and 2 mg/L) plus BA (0, 1 and 2 mg/L), or 2,4-D

(0, 0.1, 0.5, 1 and 2 mg/L) plus TDZ (0, 1 and 2 mg/L). Subsequently, two types of somatic embryos were obtained

from callus cultures and named S-type and I-type embryos. The S-type embryos were obtained from an 18-monthold

callus line which was induced and maintained at 2 mg/L TDZ and 0.1 mg/L 2,4-D near the end of each period

of the subculture. These embryos have a developmental barrier, which did not pass through the torpedo stage

and could be overcome by a supplement of 2 or 5 mg/L BA. The I-type embryos were induced from 3-month-old

callus when transferred onto induction media, i.e., MS supplemented with TDZ (2 and 5 mg/L) plus 2,4-D (0 and

0.1 mg/L). The significantly highest response, i.e., 13.3 embryos per callus clump was obtained at 2 mg/L TDZ.

In this study, the results reveal that TDZ has a crucial effect on embryogenic callus induction, proliferation and

subsequent somatic embryogenesis.

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Authors and Affiliations

Yi-Chieh Wang
Meng-Ze Lin
Bin Huang
Hsiao-Hang Chung
Jen-Tsung Chen
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Abstract

The article presents the results of a detailed study of the geological structure of the Łeba Barrier in the Rąbka cross-section (Southern Baltic, Poland). The barrier separates Lake Łebsko from the Baltic. Five sedimentary complexes were distinguished there (M2-M6). The spatial variability of the grain-size distribution was examined and succession stages of the mollusc fauna occurring in the individual sedimentary complexes were distinguished. Radiocarbon dating was used to establish the age of the most important events during the process of formation of the barrier, which took place in the course of several relative sea-level changes. The first sedimentary complex (M2) at Rąbka is connected with the second ingression (i2) of the Baltic Sea (ca. 6,700-6,000 14C years BP), sea-level stabilization (6,000-5,500 14C years BP), and at last sea-level lowering (5,500-5,000 14C years BP) in the region of the Gardno-Łeba Coastal Plain. The sedimentary complex M3 developed in a lagoonal environment when the barrier was situated north of its present position (5,000-3,000 14C BP). The next lowering of the sea-level made the lagoon shallower and caused the emergence of small but already subaerial stretches of barrier land with a freshwater fauna in the north (4,880š40 14C BP). With the next ingression stage (i3), which took place between 4,500 and 3,000 BP, the barrier shifted to its present-day position and the lagoon changed into a freshwater lake. From 3,000 to 1,700 14C BP fossil soil and peats developed on the barrier surface as a result of another sea-level lowering. The last ingression stages (i4 and i5), younger than 1,700 BP, built up the barrier, practically in its today's location (sedimentary complexes M4 and M5). The youngest sedimentary complex (M-6) is represented by present-day beach sands.

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Authors and Affiliations

Karol Rotnicki
Stefan W. Alexandrowicz
Anna Pazdur
Tomasz Goslar
Ryszard K. Borówka
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Abstract

The object of investigation was the one-strand tundish with flow control device such as gas permeable barrier (GPB). The aim of this flow control device was to activate the motion of liquid steel in the tundish longitudinal axis region. Computer simulation of the liquid steel flow and argon behaviour in isothermal turbulent motion conditions was done using the Ansys-Fluent computer program. For the validation of the hydrodynamic patterns obtained from computer simulations, a isothermal tundish glass model was used. Tundish glass model enables the recording of the visualization of fluid medium motion through the particle image velocimetry (PIV) method. Based on computer simulations, the liquid steel flow path lines in the tundish with GPB was obtained. For explain the hydrodynamic phenomena occurring in the tundish working space, the Buoyancy number has been calculated.
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Authors and Affiliations

A. Cwudziński
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Abstract

In this work studies of barrier height local values are presented. Distribution of the gate-oxide EBG(x, y) and semiconductor-oxide EBS(x, y) barrier height local values have been determined using the photoelectric measurement methods. Two methods were used to obtain the local values of the barrier heights: modified Powell-Berglund method and modified Fowler method. Both methods were modified in such a way as to allow determination of the EBG(x, y) and EBS(x, y) distribution over the gate area using a focused UV light beam of a small diameter d = 0.3 mm. Measurements have been made on a series of Al-SiO2-Si(n+) MOS structures with semitransparent (tAl = 35 nm) square aluminum gate (1 x 1 mm2). It has been found that the EBG(x, y) distribution has a characteristic dome-like shape, with highest values at the center of the gate, lower at the gate edges and still lower at gate corners. On the contrary, the EBS(x, y) distribution is of a random character. Also, in this paper, both barrier height measurements have been compared with the photoelectric effective contact potential difference fMS(x, y) measurements. These results show good agreement between distribution of the barrier heights EBG(x, y) and EBS(x, y) measurements and independently determined shape of the effective contact potential difference fMS(x, y) distribution.

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Authors and Affiliations

K. Piskorski
H.M. Przewlocki
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Abstract

Given the importance of renewable energy as it provides alternative energy sources over the traditional fossil fuel that is environmentally friendly, clean and renewable, this research aims to explore scholarly articles and books that present and investigate the challenges and barriers facing the implementation of renewable energy sources in Libya where the social, cultural, financial and awareness aspects are an important consideration against renewable energy. This study contains a review of all relevant, peer-reviewed, and published articles from journals, websites, books, conference proceedings and bulletins. An extensive literature review was carried out with the aim of researching renewable energy in Libya. This was done to take a realistic perspective of the community and the knowledge services accessible. The review of literature has shown that further renewables energy research remains necessary as the current conditions of the energy sector in Libya need to be examined to understand the challenges and difficulties to introduce renewable energy within competent authorities and businesses are examined in accordance with their managers. This indicates the need to conduct various studies in Libya to explore the various challenges, mostly financial and technological, that face the purposeful implementation of renewable energy resources in Libya. Additionally, the level of awareness and culture perception of the use of renewable energy is an important aspect to be considered as reported as barriers affecting the implementation of renewable energy in various parts of the world.
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Authors and Affiliations

Mussa Mohamed Bahour
1
ORCID: ORCID
M.F.M. Alkbir
2
Fatihhi Januddi
2
Adnan Bakri
2

  1. Business School, University Kuala Lumpur, Malaysia
  2. Advance Facilities Engineering Technology Research Cluster (AFET-RC); Facilities Maintenance Engineering Section (FAME), Malaysian Institute of Industrial Technology, Universiti Kuala Lumpur (UniKL MITEC), Persiaran Sinaran Ilmu, Bandar Seri Alam, 81750, Johor, Malaysia
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Abstract

The main issue of this article are eco-bridges, pedestrian-friendly imaginary sites (enclave) of greenery in urban tissues. Discussed cases include the implementations of projects such as: the High Line in New York and the Garden Bridge in London. The main theme of the article is to compare the green bridges in the urban tissue embedded with “living root bridges”. The author of the article highlights the potential limits for “living root bridges” in the urban tissue, resulting from the climate, time of their creation and limits of urban space. She also notes the strong tendency to create green areas in the “concrete” urban structure, but also the use of artificial materials in tissue of “living root bridges”.

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Authors and Affiliations

Aneta Sarga
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Abstract

The paper presents the assumptions and methodology for investigating equivalent heat load testing of hot aircraft engine components. The basic heat loads occurring in an aircraft engine during aircraft flight are characterised. Diagrams of the proposed heat loads are presented, together with the number of cycles, and a test bench is characterised and shown to enable equivalent heat load testing of aircraft engine components.
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Authors and Affiliations

Marek Mróz
ORCID: ORCID
A.W. Orłowicz
1
ORCID: ORCID
M. Tupaj
1
ORCID: ORCID
M. Lenik
1
ORCID: ORCID

  1. Rzeszow University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszów, Poland
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Abstract

This paper aims to improve understanding of the drivers and barriers to digital transformation in asset management. Accordingly, this paper contributes to the literature by conducting a qualitative Delphi study with 15 experts (including academia, consultancy and industry) to identify, validate, and classify the drivers and barriers affecting digital transformation in asset management. As a result of the experts’ interactions, 20 barriers were identified. The main barriers to digital transformation in asset management are the following: Misunderstanding of the strategic importance of asset management, no clear vision/strategy, existing mindset and culture, inadequate asset management system, lack of understanding of digital trends, and lack of employee knowledge and skills. The study also highlights 12 drivers that are critical to the digital transformation of asset management. These include cost reductions, opportunities in condition monitoring of assets, expected benefits in asset management processes, expected benefits in risk management and others.
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Authors and Affiliations

Damjan Maletic
1
Marta Grabowska
2
Matjaž Maletic
1

  1. Faculty of Organizational Sciences, University of Maribor, Slovenia
  2. Management and Production Engineering Division, Poznan University of Technology, Poland
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Abstract

Return migration has been increasingly gaining prominence in migration research as well as in migration policies across the world. However, in some regions, such as the Caucasus, the phenomenon of return mi-gration is little explored despite its significance for the region. Based on 64 interviews with returnees and key informants together with additional online surveys with Armenian migrants, this study discusses im-portant issues about return and reintegration with policy implications. It covers voluntary returnees as well as the participants of the assisted voluntary return and reintegration programmes and presents the case for a multiplicity of the return migration motivations and experiences which are dependent on the return pre-paredness and the strategies which the returnees use.

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Authors and Affiliations

Lucie Macková
Jaromír Harmáček
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Abstract

One of the most effective designs to control the road traffic noise is the T-shaped barrier. The aim of this study was to examine the performance of T-shape noise barriers covered with oblique diffusers using boundary element method. A 2D simulation technique based on the boundary element method (BEM) was used to compute the insertion loss at the center frequency of each one-third octave band. In designed barriers, the top surface of the T-shaped noise barriers was covered with oblique diffusers. The width and height of the barrier stem and the width of its cap were 0.3, 2.7, and 1 m, respectively. Angles of he oblique diffusers were 15, 30, and 45 degrees. The oblique diffusers were placed on the top surface with two designs including same oblique diffusers (SOD) and quadratic residue oblique diffusers (QROD). Barriers considered were made of concrete, an acoustically rigid material. The barrier with characteristics of QROD, forward direction, and sequence of angles (15, 30, and 45 degrees) had the greatest value of the overall A-weighted insertion loss equal to 18.3 to 21.8 dBA at a distance of 20 m with various heights of 0 to 6 m.

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Authors and Affiliations

Mohammad Reza Monazzam
Milad Abbasi
Saeid Yazdanirad
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Abstract

Acoustic barriers which are positioned along traffic lanes are designed to protect the surroundings from excessive noise. Such structures are to reverberate, diffract and damp the propagating acoustic waves. However, this method of shielding has some disadvantages which include constraint visibility and structure-born noise. The interaction between traffic-caused movement of air mass and acoustic barriers may generate infra noise waves. That is undesirable and should be estimated. The authors undertook the research to diagnose the plausible side effect of structure-born noise of such barriers because it may influence human body (Kasprzak, 2014). As a mechanical structure, the acoustic barrier is characterized by mechanical parameters which, in the field of modal analysis, are made up of natural frequencies, damping factors and mode shapes. In this paper the authors investigated the acoustic pressure distribution in the neighborhood of a real acoustic barrier in the scope of infra noise propagation. The methods of modal analysis were used to identify natural frequencies of the barrier and dominating frequencies of propagating waves in the far field. The correlation between observed vibration and acoustic signals is presented.

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Authors and Affiliations

Andrzej Staniek
Cezary Bartmański
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Abstract

This paper presents a new concept of disinfection traditionally applied in water treatment systems. The new definition of this process results from the change in its functionality, aims and methods, which guarantee high quality of water supply. The literature review and technical practice demonstrate a demand for disinfection to act as a functional element of the integrated water distribution system and an active intermediate link between the technology of water treatment and the water distribution network. The presented concept of a disinfection process enables evaluation of water treatment, increases its effectiveness in integrated water treatment systems. Such defined disinfection addresses water conservation and its biological stability within the water supply network. The presented here new concept of disinfection assigns its new role and function in the integrated water distribution system. The controlling and diagnostic function of the disinfection defined in the paper provides a transparent and comprehensive method, with considerable application in experimental design, as well as practical solutions for integrated water distribution systems.
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Authors and Affiliations

Zbysław Dymaczewski
1
Joanna Jeż-Walkowiak
1
Michał Michałkiewicz
1
Marek M. Sozański
1
Aleksandra Makała
1

  1. Poznan University of Technology, Institute of Environmental Engineering and Building Installations
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Abstract

This research paper discusses an analytical approach to designing the active region of light emitting diodes to enhance its performance. The layers in the active region were modified and the effects of changing the width of quantum well and barrier layers in a multi-quantum light emitting diode on the output power and efficiency have been investigated. Also, the ratio of the quantum well width to the B layer width was calculated and proposed in this research paper. The study is carried out on two different LED structures. In the first case, the width of the quantum well layers is kept constant while the width of the B layers is varied. In the second case, both the quantum well and B layer widths are varied. Based on the simulation results, it has been observed that the LED power efficiency increases considerably for a given quantum well to B layers width ratio without increasing the production complexity. It is also seen that for a desired power efficiency the width of quantum well should be between 0.003 µm and 0.006 µm, and the range of B width (height) should be 2.2 to 6 times the quantum well width. The proposed study is carried out on the GaN-AlGaN-based multi-quantum well LED structure, but this study can be extended to multiple combinations of the semiconductor structures.
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Bibliography

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Authors and Affiliations

Lokesh Sharma
1
Ritu Sharma
1

  1. Department of Electronics and Communication Engineering, Malaviya, National Institute of Technology, Jaipur, Rajasthan 302017, India
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Abstract

The performance of HgCdTe barrier detectors with cut-off wavelengths up to 3.6 μm fabricated using metaloorganic chemi- cal vapour deposition operated at high temperatures is presented. The detectors’ architecture consists of four layers: cap contact, wide bandgap barrier, absorber and bottom contact layer. The structures were fabricated both with n- and p-type absorbing layers. In the paper, different design of cap-barrier structural unit (n-Bp′, n+-Bp′, p+-Bp) were analysed in terms of various electrical and optical properties of the detectors, such as dark current, current responsivity time constant and detectivity.

The devices with a p-type cap contact exhibit very low dark current densities in the range of (2÷3)×10-4 A/cm2 at 230 K and the maximum photoresponse of about 2 A/W in wide range of reverse bias voltage. The time constant of measured de- vices with n-type cap contact and p-type absorbing drops below 1 ns with reverse bias while the detectivity is at the level of 1010 cm Hz1/2/W.

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Authors and Affiliations

Małgorzata Kopytko
ORCID: ORCID
A. Kębłowski
W. Gawron
P. Madejczyk
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Abstract

This paper analyses the possibility of applying thermal barrier coatings (TBCs) onto a substrate made of the AlSi7Mg alloy, intended for, among other things, internal combustion engine components. Engine components made of aluminum-silicon alloys, especially pistons and valve heads, are exposed to high temperature, pressure and thermal shock resulting from the combustion of the fuel-air mixture. These factors cause degradation of these components and can lead to damage. To minimize the risk of damage to engine components caused by heat stress, one way is to apply TBCs. Applying TBCs coatings to engine components improves their durability, increases power output and reduces fuel consumption. The research scope includes the application of an Al2O3-TiO3 coating via the APS (Air Plasma Spraying or Atmospheric Plasma Spraying) method onto a substrate of the AlSi7Mg alloy, analysis of the microstructure and chemical composition of the substrate and coating material, and assessment of the quality of the coating's bond with the AlSi7Mg alloy substrate using the scratch test method.
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Bibliography

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Authors and Affiliations

Marek Mróz
ORCID: ORCID
Patryk Rąb
ORCID: ORCID

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Abstract

Montmorillonite (MMT), a natural absorbent agent, has widely been accepted for its antidiarrhea function in human and farm animals; however, its specific physicochemical property limits its biological function in practical use. In the current study, raw MMT was loaded by andrographolide, namely andrographolide loaded montmorillonite (AGP-MMT). The microstructure of AGP-MMT was observed by scanning electron microscope (SEM) and X-ray diffraction (XRD). The effect of AGP-MMT on the growth performance, intestinal barrier and inflammation was investigated in an enterotoxigenic Escherichia coli (ETEC) challenged mice model. The results show that the microstructure of MMT was obviously changed after andrographolide modification: AGP-MMT exhibited a large number of spheroid particles, and floccule aggregates, but lower interplanar spacing compared with MMT. ETEC infection induced body weight losses and intestinal barrier function injury, as indicated by a lower villus height and ratio of villus height/crypt depth, whereas the serum levels of diamine oxidase (DAO), D-xylose and ETEC shedding were higher in the ETEC group compared with the CON group. Mice pretreated with AGP-MMT showed alleviated body weight losses and the intestinal barrier function injury induced by ETEC challenge. The villus height and the ratio of villus height/crypt depth, were higher in mice pretreated with AGP-MMT than those pretreated with equal levels of MMT. Pretreatment with AGP-MMT also alleviated the increased concentration of serum tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), and the corresponding genes in the jejunum induced by ETEC infection in mice. The protein and mRNA levels of IL-1β were lower in mice pretreated with AGP-MMT than those with equal levels of MMT. The results indicate that AGP-MMT was more effective in alleviating intestinal barrier injury and inflammation in mice with ETEC challenge than MMT.
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Authors and Affiliations

P. Wang
1
L. Li
1
L. Gan
1
Q. Chen
1
H. Qiao
1
W. Gao
1
Y. Zhang
1
J. Wang
1

  1. College of Biology Engineering, Henan University of Technology, Zhengzhou, China
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Abstract

In this paper, thermal oxidation resistance of silicide-coated niobium substrates was tested in a temperature range of 1300–1450°C using an HVOF burner. Pure niobium specimens were coated using the pack cementation CVD method. Three different silicide thickness coatings were deposited. Thermal oxidation resistance of the coated niobium substrates was tested in a temperature range of 1300–1450°C using an HVOF burner. All samples that passed the test showed their ability to stabilize the temperature over a time of 30 s during the thermal test. The rise time of substrate temperature takes about 10 s, following which it keeps constant values. In order to assess the quality of the Nb-Si coatings before and after the thermal test, light microscopy, scanning electron microscopy (SEM) along with chemical analysis (EDS), X-ray diffraction XRD and Vickers hardness test investigation were performed. Results confirmed the presence of substrate Nb compounds as well as Si addition. The oxygen compounds are a result of high temperature intense oxidizing environment that causes the generation of SiO phase in the form of quartz and cristobalite during thermal testing. Except for one specimen, all substrate surfaces pass the high temperature oxidation test with no damages.
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Authors and Affiliations

Radosław Szklarek
1 2 3
Tomasz Tański
1
ORCID: ORCID
Bogusław Mendala
1
Marcin Staszuk
1
ORCID: ORCID
Łukasz Krzemiński
1
Paweł Nuckowski
1
Kamil Sobczak
3

  1. Silesian University of Technology, ul. Akademicka 2A, 44-100 Gliwice, Poland
  2. Spinex Spinkiewicz Company, Klimontowska 19, 04-672 Warsaw, Poland
  3. Łukasiewicz Research Network – Institute of Aviation, al. Krakowska 110/114, 02-256 Warsaw, Poland
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Abstract

The composite weir-gate structure is considered an important hydraulic structure. This is because of its widely used in civil engineering hydraulic works especially in an irrigation system to measure, control, divert and keep the required water level. This study focuses on the influence of barrier existence on the hydraulic parameters that described the hydraulic characteristics of composite weir-gate hydraulic structure. In this study, several experimental runs were conducted to determine the effect of barrier's location, spacing and number on the water level and depth at the downstream region of flume, discharge coefficient of composite hydraulic structure, and flow rate throughout the flume. Our experiments indicated that the turbulence intensity, inlet effect, and position, gap, and number of barriers have affected the hydraulic behavior of weir-gate structure. This appears clearly by obtaining different results of discharge coefficient and flow rate that cross the weir-gate structure comparing with same cases without barriers. Also this study gives some insights on the significance roles of fluid separation, eddies generation near the barrier, fluid resistance and overlap between overflow and underflow velocities and their effects on hydraulic factors that dominate the problem. These hydraulic factors must be considered in the design and construction of barrier/barriers in open channel to prevent any fluctuation or drop in discharge, water elevation and the required water depth at downstream region.

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Authors and Affiliations

Rafi M. Qasim
Ihsan A. Abdulhussein
Khalid Al-Asadi
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Abstract

Environmental awareness among the masses compelled many companies to adopt sustainable practices in their business operations. Remanufacturing is a well-tested and successful business model practiced in many European countries. But in many African and Asian countries, it is still nascent, including India. This research study tries to identify the critical factors in the “Operational Management” area for the viability of remanufacturing business in India. For this purpose, a questionnaire was developed based on the important factors identified from the extensive literature review. An online questionnaire survey was conducted among Indian white goods appliance manufacturing companies and their suppliers. The responses were analyzed statistically and ranked based on their criticality in initiating remanufacturing business in India. The findings may help the Indian government and manufacturing firms to frame proper strategies related to the operational management issues of remanufacturing business in India.
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Authors and Affiliations

Ajay Kumar Sinha
Hanumantha Rao P.
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Abstract

The subject of the research is one of the largest World’s mine tailings disposal sites, i.e. Żelazny Most in the Legnica-Głogów Copper Mining District (south-western Poland), where flotation tailings are poured out after copper ore treatment. The protective hydraulic barrier made of 46 vertical drainage wells was characterized and evaluated in view of reduction of major contaminants (Cl, Na, SO4, Ca) migrating from the facility to its foreground. The efficiency of groundwater protection was determined on the basis of a new approach. In applied method the loads of characteristic and commonly recognizable compounds, i.e. salt (NaCl) and gypsum (CaSO4) were calculated, instead their chemical components. The temporal and spatial variability of captured main contaminants loads as well as its causes are discussed. The paper ends with the results of efficiency analyses of the barrier and with respect to the predicted increase in contaminant concentrations in the pulp poured out to the tailings site.
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Authors and Affiliations

Robert Duda

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