bluuebunny/crossref_metadata_2025 huggingface dataset:
Mining S-PLUS for Metal-poor Stars in the Milky Way
Authors: Placco Vinicius M. , Almeida-Fernandes Felipe , Arentsen Anke , Lee Young Sun , Schoenell William , Ribeiro Tiago , Kanaan Antonio
Published: August 2022

This work presents the medium-resolution (R ∼ 1500) spectroscopic follow-up of 522 low-metallicity star candidates from the Southern Photometric Local Universe Survey (S-PLUS). The objects were selected from narrowband photometry, taking advantage of the metallicity-sensitive S-PLUS colors. The follow-up observations were conducted with the Blanco and Gemini South telescopes, using the COSMOS and GMOS spectrographs, respectively. The stellar atmospheric parameters (T
eff,

log

g

, and [Fe/H]), as well as carbon and α-element abundances, were calculated for the program stars in order to assess the efficacy of the color selection. Results show that

92

−
3

+
2

%

of the observed stars have [Fe/H] ≤ −1.0,

83

−
3

+
3

%

have [Fe/H] ≤ −2.0, and

15

−
3

+
3

%

have [Fe/H] ≤ −3.0, including two ultra metal-poor stars ([Fe/H] ≤ −4.0). The 80th percentile for the metallicity cumulative distribution function of the observed sample is [Fe/H] = −2.04. The sample also includes 68 carbon-enhanced metal-poor stars. Based on the calculated metallicities, further S-PLUS color cuts are proposed, which can increase the fractions of stars with [Fe/H] ≤ −1.0 and ≤ −2.0 to 98% and 88%, respectively. Such high success rates enable targeted high-resolution spectroscopic follow-up efforts, as well as provide selection criteria for fiber-fed multiplex spectroscopic surveys.
A Blind All-sky Search for Star Clusters in Gaia EDR3: 886 Clusters within 1.2 kpc of the Sun
Authors: He 何 Zhihong 治宏 , Wang 王 Kun 坤 , Luo 罗 Yangping 杨平 , Li 李 Jing 静 , Liu 刘 Xiaochen 效臣 , Jiang 蒋 Qingquan 青权
Published: August 2022

Although previous searches for star clusters have been very successful, many clusters are likely still omitted, especially at high-Galactic-latitude regions. In this work, based on the astrometry of Gaia EDR3, we searched nearby (ϖ > 0.8 mas) all-sky regions, obtaining 886 star clusters, of which 270 candidates have not been cataloged before. At the same time, we have presented the physical parameters of the clusters by fitting theoretical isochrones to their optical magnitudes. More halo members and expanding structures in many star clusters were also found. Most of the new objects are young clusters that are less than 100 million years old. Our work greatly increased the sample size and physical parameters of star clusters in the solar neighborhood, in particular, 46 clusters are newly found with ∣b∣ > 20°, which represents a nearly threefold increase in the number of clusters at high-Galactic-latitude regions.
Limits on Hierarchical Black Hole Mergers from the Most Negative χ
eff Systems
Authors: Fishbach Maya , Kimball Chase , Kalogera Vicky
Published: August 2022

It has been proposed that some black holes (BHs) in binary black hole (BBH) systems are born from “hierarchical mergers” (HMs), i.e., earlier mergers of smaller BHs. These HM products have spin magnitudes χ ∼ 0.7, and, if they are dynamically assembled into BBH systems, their spin orientations will sometimes be antialigned with the binary orbital angular momentum. In fact, as Baibhav et al. showed, ∼16% of BBH systems that include HM products will have an effective inspiral spin parameter, χ
eff < −0.3. Nevertheless, the LIGO–Virgo–KAGRA (LVK) gravitational-wave (GW) detectors have yet to observe a BBH system with χ
eff ≲ −0.2, leading to upper limits on the fraction of HM products in the population. We fit the astrophysical mass and spin distribution of BBH systems and measure the fraction of BBH systems with χ
eff < −0.3, which implies an upper limit on the HM fraction. We find that fewer than 26% of systems in the underlying BBH population include HM products (90% credibility). Even among BBH systems with primary masses m
1 = 60 M
⊙, the HM fraction is less than 69%, which may constrain the location of the pair-instability mass gap. With 300 GW events (to be expected in the LVK’s next observing run), if we fail to observe a BBH with χ
eff < −0.3, we can conclude that the HM fraction is smaller than

2.5

−
2.2

+
9.1

%

.
Relationship between Family Knowledge and Compliance in Medication for Schizophrenia Outpatient at Prof. M. Ildrem Mental Hospital
Authors: Nuralita Nanda , Khairunisa Dita
Published: August 2022

BACKGROUND: Schizophrenia is a global health problem that demands care and support. Compliance with taking medication for schizophrenia patients is influenced by the efficacy of taking medication, support for patients, side effects of drugs, and patient attitudes. The family is the closest person to the patient who has an important role in the patient’s recovery.

AIM: The objective of the was to determine the relationship between family knowledge and compliance with schizophrenia outpatient at Prof. M. Ildrem Mental Hospital.

METHODS: This study was a comparative analytic study using a cross-sectional design. Questionnaire data obtained from 50 respondents of schizophrenia patients and 50 of their families were processed and then analyzed using the Chi-square test.

RESULTS: Chi-square test with p = 0.008, <α 0.05, indicating that there is a relationship between family knowledge and adherence to medication in schizophrenia outpatients.

CONCLUSION: Many factors affect compliance in the treatment of schizophrenic patients, one of which is the level of family knowledge about schizophrenia. Family knowledge about schizophrenia is very important, because the higher the level of family knowledge about schizophrenia, the patient’s adherence to treatment will also be better.
Asbestos and anti-asbestos activism: medical and economical aspects
Authors: Jargin Sergei
Published: August 2022

Asbestos-related risks have been estimated on the basis of data from the past, when professional exposures were higher. Fibers are present in the environment due to erosion of surface deposits and human activities unrelated to asbestos industry. If searched for, asbestos fibers are frequently found at autopsies. Bias can be encountered in asbestos research e.g. attributing of mesothelioma and lung cancer to asbestos when fibers are found, although cause-effect relationships remain unproven. Some studies rely on work or residence histories of questionable reliability. Asbestos is a low-cost material and an excellent reinforcing fiber. Different asbestos types have their technical advantages and preferred application areas. The traffic is safer with asbestos-containing brake linings. Chrysotile cement constructions are sturdy and inexpensive. The fireproofing properties of asbestos are well known. It can be reasonably assumed that the non-use of asbestos-containing brakes, fireproofing and insulation lagging has increased the damage and numbers of victims of traffic accidents, fires and armed conflicts. Nowadays, when a probability of conflicts seems to be enhanced, the attitude to asbestos should be changed. Most importantly, asbestos-related science must be separated from economical and political interests. Reliable information can be obtained in lifelong bioassays.
Petrography and structural features of the Precambrian basement rocks in the Benin-Nigerian Shield, NW Nigeria: Implications for their correlation with South Atlantic Precambrian terranes
Authors: Sunkari Emmanuel Daanoba , Kore Basiru Mohammed , Tetteh Samuel Edem Kodzo
Published: August 2022

This study investigated the petrographic and structural features of the Precambrian (Neoproterozoic) basement rocks of the Benin-Nigerian Shield that crop out in northwestern Nigeria within Kanoma and its environs to give an insight into the evolution and deformational episodes that pervaded them. The major rock types in the area are schists and quartzites, which have been intruded by granitic rocks that appear to be metamorphosed. The origin of these rocks is attributed to the Eburnean Precambrian orogenic episode and the Pan-African orogeny, which started and ended with the intrusion of the granite suites. The dominant mineralogy associated with the rock types includes quartz, orthoclase, plagioclase, microcline, biotite, chlorite, and very few accessory minerals. The schist shows the dominance of quartz, feldspars (alkali and plagioclase), biotite, muscovite, chlorite, and opaque minerals. The quartzite is typically dominated by quartz that appears recrystallized in places, whereas the meta-granite contains quartz, feldspars (alkali and plagioclase), biotite, and opaque minerals. Structural features such as joints, quartz veins with minor folds, and faults observed in the lithological units have a predominant N-S trend and are the imprints of the last tectonic event (Pan-African orogeny). The level of deformation in Kanoma led to the development of N to NNE trending moderately (S1) to steeply (S2) dipping foliations in the schist. The evolution of these deformational mechanisms from moderately dipping foliations to steeply dipping foliations along the N to NNE- trend is associated with late orogenic uplift and exhumation following oblique convergence during the Pan-African orogeny. Structural overprinting relations recognized within Kanoma and its environs allow us to decipher the geologic structures into three successive Pan-African deformational events (D1–D3). D1 fabrics are manifested by simple anticline micro folds in the schist. The D2 structures are the predominant ones in the area comprising the N-S directional joints and faults. The D3 phase of deformation is a progressive one, which started as N-S high angle thrusts and thrust-related folds that resulted from the NE–SW contraction during the orogenic episodes. The studied rocks can be correlated with the Pan-African and Brasiliano belts based on their overlapping features.
Advancing Diversity and Inclusion Management Consulting in Hospital Settings
Authors: Sabie-Aridi Amalisha S. , Burrell Darrell Norman , Richardson Kevin , Lewis Eugene , Wright Jorja B. , Kemp Roxanne Elliott
Published: August 2022

This analysis takes a deep dive into how a U.S. hospital, at risk of losing millions of dollars from a contract because of unfair hiring practices and discriminatory promotion practices among racial minorities. The hospital is also facing a class-action nursing discrimination lawsuit. The employee perception is that the organization is biased against African American, Native American, and Latino nurses with hiring, promotions, bonuses, training opportunities, and management job opportunities. These groups have representation numbers in their nursing workforce of less than 5 percent. The focus of the study is an exploration of the consequential impact of a non-diverse and inclusive workplace. An action research approach used included fact-finding interviews, barrier analysis, company policy assessments, content analysis of the problem in the literature, and recommendations based on the amalgamation of the triangulated data.
Active and Passive Solutions for an Energy Efficient Building
Authors: Teixeira G.P.L. , Guimarães A.S. , Delgado J.M.P.Q.
Published: August 2022

In addition, the majority of electricity consumed in buildings (58%) should come from renewable sources. Together with solar thermal, modern biomass, and district heating, overall renewables could ramp up to 81%, from 36% today’s contribution for the sector. Nonetheless, to materialize these predictions, a global investment of around USD 32 trillion (28 trillion euros) is expected between now and 2050. In the European Union, the nearly zero-energy building standard (nZEB) will be obligatory for all new buildings by 2021. Although the increase in energy demand will be reduced with this measure, it does not really affect the energy consumption at present. It is imperative to design energy efficiency retrofit and renovation financing schemes. For many years to come, only measures taken in existing buildings will have a significant effect on the total energy demand in the building stock. Firstly, this work presents a brief analysis of active and passive solutions for an energy-efficient building. Secondly, in this work it identified a set of active and passive solutions, which, in a combined way, develop the thermal performance of a residential building, allowing it to become energetically autonomous. The program EnergyPlus was used to execute the thermo-energetic simulations for the diverse scenarios considered, in the study case. The numerical results showed that the implementation of passive solutions improves the energy performance of the buildings, and the use simultaneously of an active solution, a renewable energy source, allows the reach of the energy-autonomous of the building.
Study on a Recycling Solution of Basic Oxygen Furnace Slag in Pelletizing Process
Authors: Nguyen Cao Son
Published: August 2022

Basic oxygen furnace slag (BOF slag) contains high amount of useful oxides such as CaO, MgO, SiO2, etc., therefore, a solution of the slag recycling would be used as a flux in pelletizing process. To understand role of slag in the pellet, this research examines the mechanical, chemical and microstructure properties of the pellets containing various amount of the slag. In the experimental process, the green pellets were made from a mixture of bentonite, iron ore and the slag. The green pellets were sintered in the resistance heating furnace maintaining temperature at 1200 °C for 120 minutes. Then the fired pellet was tested strength and observed microstructure with variation of the slag amount in the pellets. The result shown that cold compression strength of the pellets containing from 1.06 to 18.45 mass% slag was higher values than 200 kg/p, hence, the pellet was able to charge the pellets into the blast furnace. The highest strength was 342 kg/p with 5.08 mass% slag in the pellet. Besides, optical observed microstructure of the pellet indicated the phases of magnetite, hematite and silicate. In addition, the obtained results shown that there was a deterioration of porosity with increasing the slag amount. Accordingly, the porosity got a slight decrease when the slag amount increased from 1.06 to 5.08 mass% in the pellet. Once the amount of the slag was higher than 5.08 mass%, the porosity significantly reduced with increasing the slag amount; the porosity decreased from 23 to 12 %.
Prediction of the Structural Properties of Powder Materials by 3D Modeling Methods
Authors: Ruban Artem , Pasternak Viktoriya , Huliieva Nataliia
Published: August 2022

This article examines the main problems of modelling spherical (circular) particles. The main method of the initial process of filling lobules using the Cauchy and Reynolds problem is substantiated. An image of an object-oriented complex of free fall of a spherical particle and their many non-collision spheres is presented. Based on the obtained research results, the main parameters of the process of filling particles of heterogeneous materials. An example of visualization of the developed software product for filling material particles is given, taking into account a number of cross-sections of a cylindrical hopper in height. A histogram of the distribution of material particles from porosity over the volume of a cylindrical hopper is also constructed.
Effect of Buffer Layer on In Situ Temperatures in Laser Cladding
Authors: Thawari Nikhil , Chaitanya Chaitanya , Chandak Aayush , Gupta T.V.K.
Published: August 2022

In laser cladding process, generation of high temperature gradients significantly impacts the output coating parameters such as mechanical and microstructural properties. Buffer layer addition between hard alloys cladding shows reduction in crack formation and also dilution rates. The present study is on Insitu temperature monitoring in laser cladding of Stellite 6 alloy with addition of buffer layer, which were compared with direct deposition of Stellite 6. The results show about 17 - 20 % low substrate temperatures with a buffer layer, indicates more uniform cooling of the hard coatings than direct cladding. The increase in laser power measures 35 - 40 % higher temperatures in both the cases due to large heat addition at the clad region. The study provides an insight into the substrate temperature evolution in cladding with and without a buffer layer.
Effects of N-Octadecane as PCM on the Thermal and Mechanical Properties of Polyurethane Foams Utilizing Coconut-Based Polyols
Authors: Magdadaro Miceh Rose D. , Capangpangan Rey Y. , Lubguban Arnold A. , Alguno Arnold C.
Published: August 2022

The utilization of vegetable oil in producing bio-based polyol, as an alternative replacement to petroleum-based polyol in making polyurethane (PU) foam has gained a lot of interest due to its finite supply and low production cost. In this study, bio-based polyol using coconut oil as raw material produced PU foam as thermal insulation material. The vegetable oil-based polyol was prepared using a two-step method, while PU foams were prepared by the free-rise method. In order to enhance the thermal properties of the produce PU foams, phase change material (PCM) was added to the PU foam formulation. FTIR spectra result showed peaks at 2920 cm-1 and 2850-1, which signifies the CH2 asymmetric stretching, indicating that n-octadecane was successfully incorporated into PU foams. Moreover, heat flow meter (HFM) and thermo-gravimetric analysis (TGA) show PU foam with 1% n-octadecane shows better thermal properties than other produced PU foams. Furthermore, the universal testing machine (UTM) result shows an enhancement in the mechanical properties of the produced PU foam. These results demonstrate that the addition of n-octadecane to the PU foam formulation improved the mechanical properties of PU foams while enhancing their thermal properties.
One-Pot Synthesis and Antioxidant Activity of 4-Phenoxyquinoline Derivative from Clove Leaf Oil
Authors: Lubis Siti Masitah , Hariadi Muhamad Fadhly , Amalia Nilna , Inung Masni , Purwono Bambang , Priatmoko  , Mardjan Muhammad Idham Darussalam
Published: August 2022

Synthesis and antioxidant assay of 4-phenoxyquinoline derivative namely, (E)-7-chloro-4-(2-methoxy-4-(prop-1-en-1-yl)phenoxy)quinoline, from clove leaf oil have been conducted. This compound can be prepared from eugenol (isolated from clove leaf oil) in either two-step or one-pot synthesis. In two-step synthesis, eugenol was subjected to base-catalyzed-isomerization to give isoeugenol, which in turn underwent aromatic nucleophilic aromatic nucleophilic substitution with 4,7-dichloroquinoline to generate (E)-7-chloro-4-(2-methoxy-4-(prop-1-en-1-yl)phenoxy)quinoline in 57% total yields. By combining these two reactions, the 4-phenoxyquinoline derivative can be furnished in one-pot fashion in 63%. The results showed that the synthesized 4-phenoxyquinoline derivative, however, did not show strong antioxidant activity.
Challenges and Opportunities of Implementing Industry 4.0 in Recycling Carbon Fiber Reinforced Composites
Authors: Amantayeva Akniyet , Shehab Essam , Meiirbekov Arshyn , Suleimen Aidar , Tokbolat Serik , Sarfraz Shoaib
Published: August 2022

At the time of unprecedented development of digital technologies, business owners across various industries need to stay up-to-date in terms of using cutting-edge technologies such as Industry 4.0 to ensure competitive performance. There are still many areas where their positive implications of digital technologies have not been applied. For example, the end-of-life (EoL) waste from the automotive, aerospace, and wind energy industries is still accumulating in landfills. At present, an increasing number of vehicles, airplanes, and wind turbine blades are made of Carbon Fiber Reinforced Polymer Composites (CFRPs) leading to an urgent demand for implementing sustainable waste disposal strategies. Thus, recycling CFRPs is a key research area that provides a potential for improvement, particularly, in terms of digitalization. This study addresses the issues prevalent in this sphere and proposes Industry 4.0 related technologies to be integrated into the CFRP recycling supply chain stages, including waste collection, dismantling, transportation, recycling, and re-manufacturing. For this purpose, key technologies were selected from the literature review, smart recycling trends were defined and relevant analysis was carried out to map technologies onto the CFRP recycling supply chain.
Investigation of Mechanical Strength and Weight Fraction of Date Palm Fibre Hybrid Composites Reinforced with Polyethylene
Authors: Mohanavel V. , Sathish T. , Kumar S. Dinesh , Ravichandran M. , Kumar S. Suresh , Rajkumar Sivanraju , Subbiah Ram
Published: August 2022

Polyethylene, elastomer, and date palm fibre are all readily available, it have an positive impact on growth of new composite materials with desirable features and characteristics. There are many different types of composites, but they all have the same goal: to create a new material with greater qualities than the constituent materials. Date palm fibre was employed to reinforce a composite matrix made of polyethylene (PE) plastic and elastomer. To find out the tensile, impact, and bending strength values of composites by weight fractions of 25% (75:25), 35% (65:35), and 45% (55:45), this research set out to find (55:45). Composites with a weight percentage of 25% (75:25) had less Tensile strength (TS) 1.213 MPa, though mixtures with weightage proportion of 45% (55:45) had the maximum TS of 2.613 MPa. The minimum tensile strain value was discovered in composites with a weight fraction of 25% (75:25), while the maximum tensile strain value was identified in composites with weight fraction of 45 percent (0.0067). (55:45). 45 % (45-55) weight ratio mixture had the minimum impact strength of 45321 kJ/mm2, while the 25 percent (75-25) weight ratio mixture had the maximum impact strength of 17721.41 kJ/mm2. A 25 percent weight fraction (75:25) composite had the lowest bending strength measurement result (1.816 MPa), whereas a 35 percent weight fraction (65:35) composite had the highest measurement result (4.9 MPA) in this category. At 75:25 (75:25), the bending strain of the composite was at its highest, with a value of 0.0216
Evaluation of Corrosion Inhibition of Plasma Sprayed FsHA/YSZ Coating on β-Titanium (Ti-13Nb-13Zr) Alloy Using Electrochemical Techniques
Authors: Anene Franklin Amaechi , Jaafar Che Nor Aiza , Zainol Ismail , Mohamed Ariff Azmah Hanim , Mohd Tahir Suraya
Published: August 2022

α + β titanium alloys especially Ti-6Al-4V alloy have dominated implant industry over the years due to their high corrosion resistance, strength, and flexibility. However, their high modulus (110GPa) compared to the human bone (18-30GPa) results in aseptic loosening of implants. Hydroxyapatite (HA) coating on Ti-6Al-4V alloys has been used to mitigate these demerits, nevertheless, more still need to be done. Hence, the present study aims at developing a natural and economical bioceramic coating on low modulus Ti-13Nb-13Zr alloy substrates using plasma spraying technique for biomedical applications. The bioceramic used was natural HA derived from fish scales (FsHA) and FsHA doped yttria stabilized zirconia at (10-20 wt.%). FsHA/YSZ powders and the coated samples were examined by XRD and SEM/EDX and the surface roughness, microhardness and corrosion resistance of the uncoated substrate and coated samples determined. The XRD pattern showed good crystalline FsHA/YSZ powders for all the compositions while the microstructure of the coatings revealed a fine splat lamellar morphology with partially melted and non-melted FsHA particles along with evenly dispersed Zr particles within the coating matrix for the FsHA/YSZ coatings. The maximum surface roughness (4.215 µm) was found with the FsHA coating while FsHA/YSZ coatings presented the highest hardness values (492.5-536.9 Hv) compared to the FsHA coating (467.8 Hv) and the uncoated substrate (385.9 Hv). Similarly, the corrosion resistance of the Ti-13Nb-13Zr alloy was significantly improved with the deposition of FsHA/YSZ bioceramic coatings.
Impact of Heated Air Indirectly Produced by Photovoltaic Panels on Indoor Thermal Comfort
Authors: Oliveira A.C.C. , Rodrigues L. , Guimarães A.S. , Delgado J.M.P.Q.
Published: August 2022

Climate change is one of the most debated issues today around the world, given its global impact. The construction industry in the European Union (EU) accounts for 40% of energy consumption and 36% of greenhouse gas emissions. Thus, the continuous improvement of energy efficiency in buildings plays a key role in achieving the carbon neutrality goal by 2050. At a time when the irreversible point of global warming may have already been reached, change becomes urgent, with one of the solutions being the use of renewable energies. Among renewable energies, solar is considered not only one of the most promising ones but also one of the energies with the greatest potential growth. The accelerated use of solar PV allows a reduction of carbon dioxide of approximately 4.9 gigatonnes. In the last decades, solar panels presented a great improvement in their efficiency and power output over and, in addition to the production of electricity, their heat can also be harnessed. Therefore, the objective of this work is to study a photovoltaic panel solution in which the heat produced indirectly by it contribution to the heating of a house and, consequently, to thermal comfort. In this work, it was analysed the feasibility of a PV solution that intends to take advantage of the hot air, indirectly produced by it, for subsequent heating of a house. Numerical simulations were performed using Ansys®Fluent, Release 18.1, software and considering a 3D model of a house with PV panels installed in the roof. The results showed the solution under study is not feasible in winter, since solar radiation is not enough for heating using this contribution. However, this solution, although not avoiding the use of other heating means, can help in heating, contributing to the reduction of some needs.
Improving the Mechanical Properties of Liquid Hydrocarbon Storage Tank Materials
Authors: Sierikova Olena , Koloskov Volodymyr , Degtyarev Kirill , Strelnikova Olena
Published: August 2022

Methods for effective modules evaluation of materials with nanoinclusions of different shapes have been developed. The strength and dynamic characteristics of tanks and structures of fuel tanks and cisterns were determined by solving hydroelastic interaction issues. Especially important are the researches of the structures strength under the impulse, shock and seismic loads conditions. The crucial issue of ensuring the reliability and trouble-free operation of liquid hydrocarbon storage systems today has been remain actual. The aim of the paper is to improve the mechanical properties of liquid hydrocarbon storage tank materials.The refined mathematical model has been proposed to clarify the frequencies and shapes of free tank oscillations of the partially filled by liquid due to the internal partitions presence taking into account the surface tension of the aggregate on the dynamic characteristics of liquid hydrocarbon storage tank at low gravity. The method for studying free and forced oscillations of the elastic rotation shell with the arbitrary meridian partially filled with the ideal incompressible fluid has been developed. To research the free and forced oscillations of shell structures with compartments containing liquid, the method of given shapes has been developed.Nanocomposites with aluminum matrix with steel spherical inclusions and with steel and carbon inclusions-fibers have been considered. The effective modules of these composites have been estimated. The calculations results demonstrate the obtained composite materials strengthening in the while density reducing. The method to specify the static and dynamic characteristics of shell structures made of different composite materials and partially filled with liquid has been developed. Numerical analysis of static and dynamic characteristics for the liquid hydrocarbon storage tank model has been performed.
Study the Influence of CNTs Deposited by Laser on the Surface of Al 2024 Alloy
Authors: Tawfiq Thaier Abid , Jassim Abdulsatta Mohammedr , Alani Haitham A.
Published: August 2022

Laser powder deposition (LPD) has been relied on to improve the surface properties of materials. Nowadays, an excellent reinforcement for aluminum and aluminum alloys could be carbon nanotubes (CNTs). The surface of aluminum alloy 2024 (Al Cu4Mg1) is coated with double-walled and multiwalled carbon nanotubes (DWCNTs, MWCNTs) using laser preplaced powder deposition with pulsed Nd:YAG to evaluate its effect on enhancing hardness and corrosion resistance. The laser power, pulse duration, scanning speed, and frequency, were controlled to complete this task. Since the best DWCNT deposited layer was obtained at the optimal process conditions, the Vickers micro-hardness and corrosion resistance of the coated Al 2024 surface improved in the readouts. The results showed that DWCNT improved specific essential surface attributes, namely hardness, abrasive wear resistance, and corrosion resistance, more than MWCNTs, according to the findings. Although MWCNTs have less penetration, their dispersion on the surface is superior to DWCNTs.
Copper Based Powder Metallurgy Composite for Electrical Applications
Authors: Jayasathyakawin S. , Ravichandran M. , Mohanavel V. , Kumar S. Dinesh , Sathish T. , Rajkumar Sivanraju , Subbiah Ram
Published: August 2022

This paper discusses Copper Metal Matrix Composites. It is obvious that copper matrix composites have been heavily relied upon by many industries because of their high wear resistance, corrosion resistance, excellent electrocatalytic properties, and high strength. The excellent electrical conductivity of copper-based materials also enables these materials to function as lubricants and anti-frictional materials. These materials were widely used in transportation, electrical contact transmission, and aerospace. Copper-based metal matrix composites have wide application due to their excellent mechanical, electrical, and thermal characteristics. Copper based metal matrix composites are also corrosion resistant and have a high strength. A contemporary study evaluated the effects of different parameters on powder metallurgy fabricated copper matrix metal composites. The focus was on understanding the applications and mechanical properties of copper-based composite materials.
Validation of Archimedes Method and Acid Dissolution Test for Volume Fraction Determination of Aluminum Alloy Composites Reinforced with Ceramic Particles
Authors: Saminathan Rajasekaran , Mohammed Raffic N. , Ganesh Babu K. , Hadidi Haitham , Tharwan Mohammed , Fageehi Yahya Ali , Alnujaie Ali
Published: August 2022

Metal matrix composites are the novel engineering materials finding applications in several extreme environmental and industrial requirements leading to the developments of numerous types of its kind in recent decades. Powder metallurgical techniques is one among the promising methods of producing intricate shaped end products out of the MMCs. Essentially the uniformity in distribution of the reinforcements and the accuracy in employing the percentile addition of the reinforcements decide the tailor made properties of these composites. There are several techniques to evaluate the reinforcement percentage and uniformity. This work concentrates on the analysis of effectiveness of volume fraction determination methods namely Archimedes test and acid dissolution test for 7075 Al/Al2O3 composite. Using the two methods the volume fraction of 7075Al/ Al2O3 composite prepared by powder metallurgy technique is determined. Advantages and disadvantages of both methods were analyzed using the result analysis and the observation indicated that the acid dissolution test produces more accurate results than the Archimedes test. In addition, the randomized selection of the specimens out of the end products leads to the corroboration of reinforcement uniformity in the composite matrix.
CFD Simulation of the Hydrodynamics of Core-Annular Flow of Oil, Gas and Water in Elliptic-Cylindrical Duct
Authors: de Oliveira J.L. , Magalhães Hortência Luma Fernandes , Gomez Ricardo Soares , Cavalcante Daniel César M. , Neto Guilherme Luiz Oliveira , de Oliveira Nívea Gomes Nascimento , Batista Francisco Alves , Silva Rodrigo Moura , Abreu Amanda K.F. , Almeida Arthur G.F. , de Lima Antonio Gilson Barbosa
Published: August 2022

Heavy oils, due to their high viscosity, have greater viscous resistance to flow, requiring high pumping power for transport and increasing operating cost. As an alternative to minimize this problem, the core-flow technique emerged, which consists of injecting water simultaneously with the oil flow, causing the heavy oil to be surrounded by a layer of water and flowing in the center of the duct without touching the pipe wall, consequently reducing the friction pressure gradient. Thus, this work aims to numerically study the core-annular flow of oil, water and gas in a cylindrical duct with an elliptical cross-section, considering a three-dimensional, isothermal and incompressible flow. For the numerical solution of the governing equations, the software Ansys FLUENT 15.0 was used. It was found that the lubrication provided by the water on the duct wall reduced the pressure variation by 7.20 times compared to the heavy oil single-phase flow, proving the good efficiency of the core-flow technique.
Effects of Reaction Temperature on the Antibacterial Activity of Silver Nanoparticles Synthesized from Psidium guajava Leaf Extract
Authors: Cabañog Lloyd Allan T. , Cumba Rey Marc T. , Enot Melania , Capangpangan Rey Y. , Alguno Arnold C.
Published: August 2022

Silver nanoparticles have been well known to possess efficient antibacterial properties. Many studies conducted on silver nanoparticles synthesized in different routes, from physical methods to chemical techniques to biological synthesis. In this study, the biological route was utilized using Psidium guajava leaves extract mixed with silver nitrate to synthesize silver nanoparticles. In addition, syntheses were done at varying temperatures to investigate its effect over antibacterial properties of the silver nanoparticles obtained. Results showed blueshifting of UV-Vis peaks suggesting decrease in particle size as synthesis temperature increases. FTIR also showed that the synthesized nanoparticles may have been capped by phenolic compounds from the biomolecules in guava leaves. Finally, antibacterial tests via Disc Diffusion Test suggested that the silver nanoparticles biologically synthesized at higher temperatures are more effective bactericides than those synthesized at lower temperatures as indicated by the measured zones of inhibition.
Study of the Electronic Defect States of One-Dimensional Comb-like Quantum Wires Structure with Resonator Defect by Using the Transfer Matrix Method
Authors: Machichi Siham , Elamri Fatima Zahra , Bouchafra Yassine , Ben-Ali Youssef , Falyouni Farid , Bria Driss
Published: August 2022

In this paper using the transfer matrix method (TMM), we consider an electronic comb-like waveguides system composed by the periodicity of segment semiconductor (GaAs type) of length and grafted in its extremity by one semiconductor resonator (GaAlAs type) of length . These segments and resonators are considered quantum wires. The perfect system in question presents the electronic pass bands and electronic band gaps which allow to control and manipulate the electrons waves whose energy is identical to the energy of the gaps. We insert the defect at the resonator level in the middle of this system in question. Hence, very narrow localized defect states are created in the electronic band gaps, with probably high transmission rate and very important quality factor. These localized defect states shift to low energy by increasing the resonator defect length, while is move to high energy when the resonator defect concentration increases. In this study, we consider that the segments and resonators lengths are very small in front of their sections, so that the propagation of electronic waves occurs only in a single dimension.
Developing a Digital Twin for Carbon Fiber Composites Recycling: Challenges and Future Research Direction
Authors: Shehab Essam , Kazhymurat Temirlan , Jyeniskhan Nursultan , Amantayeva Akniyet , Meiirbekov Arshyn , Singh Sumit , Tokbolat Serik
Published: August 2022

A digital twin is among the fast-growing technologies capable of increasing the dynamic development of manufacturing industry in terms of digital transformation in the context of Industry 4.0. The development of digital twin technologies for carbon fiber composites (CFC) recycling is a novel direction that significantly improves the recycling process efficiency. Among various benefits, it provides high-quality process monitoring and automated control. However, digital twins development of CFC recycling face challenges that need to be identified. This study aimed to investigate the challenges of implementing digital twin in the carbon fiber composites recycling process. Three main challenges were identified by adopting the narrative literature review approach. Understanding these challenges contributes to the digitalization of the industry and provides recommendations for further investigation of this area of research. It should be noted that optimization and validation of technical aspects will allow the creation of a solid process data management system and control crucial process variables.
Size Effect of Hemi-Toroidal Quantum Dot on the Electronic Properties in the Presence of an Off-Center Hydrogenic Shallow Donor Impurity
Authors: Boussetta Reda , Belamkadem Laaziz , Mommadi Omar , Chouef Soufiane , Hbibi Mohammed , El Moussaouy Abdelaaziz , Vinasco Juan Alejandro , Duque Carlos Alberto , Kerkour El Miad Abdelhamid
Published: August 2022

We have studied the electronic properties in presence of an off-center hydrogenic shallow donor impurity confined in GaAs semiconductor quantum dot with toroidal geometry by considering the infinite confinement potential. This study has been performed within the parabolic band and the effective mass approximations in the presence of an off-center donor impurity. Three-dimensional Schrödinger equations are discretized using the finite difference method on a mesh containing Nr*Nθ*Nφ nodes. The numerical results of the analytical calculations demonstrate that the variation of the geometrical and torus radii (Rg and Rc) has a remarkable effect on the donor energy and the average electron-impurity distance, which is quite remarkable in small hemi-Toroidal quantum dot. On the other hand, we've demonstrated that the donor atom's position has a considerable impact on their energy. Furthermore, our numerical results show that the geometrical radius and donor atom's position significantly affect the electron impurity binding energy.
Modeling of Gas Sorption Process by Dispersed Liquid Flow
Authors: Kustov Maksym , Melnichenko Andriy , Basmanov Oleksii , Tarasenko Olexandr
Published: August 2022

A mathematical model of the process of gas propagation in the atmosphere and its sorption by fine flow has been developed. The use of the finite difference method in modeling allows to obtain numerical solutions of the spatial distribution of gas concentration during its deposition by a jet of arbitrary intensity and shape. The proposed method of mathematical description of the process of sorption of hazardous gases allows you to choose an arbitrary number and spatial location of nodal points that satisfy the Courant-Friedrichs-Levy condition. The developed model allows to predict the intensity of gas sorption in technological processes and in the elimination of the consequences of emergencies. The use of the developed model will increase the efficiency of emergency management and choose effective methods of sorption of hazardous gases in the atmosphere. The results of numerical calculations confirmed the efficiency of the developed model and theoretically demonstrated the effectiveness of using water curtains for the sorption of ammonia from the atmosphere. According to the simulation results, it is established that the use of fine spray jets can significantly reduce the distance of distribution of hazardous gas.
Design and Analysis of Multi-Layered Composite Panels for In-Plane Loadings
Authors: Ahmed Awan Osama Ali , Saeed Babar , Shehzad Muhammad Arslan , Khan Muhammad Asadullah
Published: August 2022

Composites have a wide range of applications in the field of robotics, aerospace, aviation, sports, and automotive engineering. They have appealing properties such as high strength to weight ratio, good mechanical and electrical properties, and durability. Multilayered composites are prepared by stacking different layers of composites along different directions. This research focuses on the compression and tension response of multilayered composite panels without interference of bending by using in-plane loading. The aim of this research is to develop a generalized MATLAB code for a number of layers, to solve a model composite through analytical and MATLAB computations, to analyze the stress behavior in ANSYS (ACP) and finally to compare the results. For carrying out the analysis, a multi-layered, symmetric composite panel is modelled under in-plane loading. First, a mathematical model is formulized to solve the multi-layered composite panel under in-plane loading and analytical results are obtained. Next, a generic MATLAB code is developed, followed by simulations and computational study using ANSYS (ACP) module. The results of MATLAB and the solution of the mathematical model are found to be identical. Further, the results obtained from ANSYS (ACP) have shown the stresses in each layer and overall deformation of the composite panel. The overall results from three methods have shown that the stresses produced in a composite panel are symmetric across mirrored layers. However, there is a significant difference between the analytical and ANSYS (ACP) results, this is due to the limitations of the Classical Laminate Theory (CLT) which has been used in the analytical study. CLT does not take into effect the out-of-plane stresses. However, in real life scenarios, out-of-plane stresses exist under the in-plane loadings and have a significant effect around the edges and corners of the panel. If 10 percent of the edges are removed on both sides, the analytical results and simulations are found to be in good agreement. Further, after the ANSYS (ACP) analysis has been obtained for the panel, a sandwiched composite panel has been modelled by adding a core material of foam and polyethylene at the center of the composite. The thickness of the core material is varied to observe the change in the stress behavior. The results have shown that there is an increased stress behavior when a softer core is used or the thickness of the core material is increased.
Investigation of Cracks on Internal Surfaces of Extruded Cold Worked Thick Walled Pipes of an Age Hardened Al-Alloy
Authors: Jahangir Irsa , Naeem Hafiz , Faheem Abdul , Tauqir Anjum
Published: August 2022

Thick seamless pipes of hardenable aluminum alloys demand close geometrical tolerances as well as high quality surface finish which are met by cold drawing after a series of different thermo-mechanical treatments. To meet the requirements of critical applications the final product undergoes stringent quality inspection procedures. State of the art quality assessment can detect even minor isolated defects. The production facilities develop their quality criteria suitable for specific applications. The present study investigated minute defects on the inside surface of thick seamless pipes, proposed mechanism of their formation and suggested the impact of defects on the end use. The root cause analysis was conducted, and measures were suggested to control the defects. Thick extruded seamless aluminum alloy pipes underwent a series of different thermo mechanical treatments; the final dimensions with required tolerances and the surface finish were achieved by adopting a 2-step cold drawing process. Cold drawing generated residual stresses which resulted in the formation of cracks in the material, preferentially at the defects generated during solidification and/or extrusion processes. The final product underwent stringent quality inspection, and the material was rejected if cracks of size 3 mm or larger were detected. The die scratches or notches generated on the inside surface of the pipes, during extrusion are assumed to grow if subjected to high stresses during subsequent processes, e.g. cold working. Observations at high magnification in SEM helped to determine the morphology of cracks. Radiographic testing did not detect any crack in the bulk material. Particles with faceted features indicated the presence of inclusion. Inclusions were detected in the form of strings along the direction of cold drawing. Energy dispersive spectrometry in SEM was used to determine the composition of inclusion detected in the vicinity of cracks. Almost all the inclusions were rich in silicon, iron, calcium along with carbon; it indicated that the inclusions were trapped particles of fluxes, slag, and brick powder. Particles rich in Ca, Na and/or Cl indicated entrapped flux, Fe and Si were mostly coming from aluminum scrap and refractory powder while presence of carbon indicated entrapped extrusion lubricant. Inclusions rich in a large variety of unwanted elements indicated presence of slag particles. Numerical analysis was conducted to develop a model in FEM in which scratches of different depths were introduced and autofrettage pressure was applied to determine the stresses generated according to the established Von Mises Model; the latter was used to establish the yield criteria. Finite Element Modelling concluded that when cold drawing pressure was applied on a pipe with a single notch of depth 0.3mm or three notches of depth 0.1 or greater at different locations the Von Mises stresses approached the yield strength of the pipe.
Using the PLD Method: Investigation of the Influence of Laser Wavelengths on the Optical Morphological and Structural Findings of LiNbO3 Nano-Photonic Films
Authors: Salim Evan T. , Mahmood Rooa , Khalid Farah G. , Hashim Uda
Published: August 2022

For the optoelectronics application like (optical waveguides), a nanostructure Lithium Niobate (LiNbO3) Nano film was produced and placed on a quartz substrate using the pulse laser deposition (PLD) process. The structural, morphological, and optical features of wavelengths od pulsed laser (1064 and 532) nm were investigated for the films of LiNbO3 Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Ultra-Violet (UV-Vis) spectrophotometer, and Atomic Force Microscopy (AFM) are among the techniques used to describe and evaluate the samples.
Study on the Effect of Adhesive Systems on Physical and Mechanical Behaviour of Kenaf Fiber Reinforced Beech Wood
Authors: Kumar S. Dinesh , Sathish T. , Mohanavel V. , Ravichandran M. , Kumar S. Suresh , Rajkumar Sivanraju , Subbiah Ram
Published: August 2022

Kenaf fiber-reinforced beech plywood was evaluated with 5variantmanufacturing adhesive methods in order to increase its acceptance in the wider industrial use. We aimed in enhancing the mechanical characteristics of beech wood kenaf fiber-reinforced using epoxy resin, Urea-formaldehyde, Melamine urea-formaldehyde, isocyanate MDI prepolymer and polyurethane and exhibited diverse effects. Tensile strength, Modulus of Elasticity, Modulus of Rupture, Shear Strength and Screw withdrawal resistance were enhanced by urea formaldehyde, while tensile strength was decreased by Urea Formaldehyde, Melamine Urea-Formaldehyde and isocyanate prepolymer. Epoxy resin, on the other hand, is well suited for kenaf fibre reinforcing. For example, polyurethane reduced the mechanical characteristics of kenaf fibre reinforced beech wood. Shear strength, Modulus of Elasticity and Modulus of Rupture were all superior than glass fibre reinforced epoxy resin bound beech wood.