scholarly journals Post-impact mechanical characterization of HMPE yarns

2021 ◽  
Vol 61 (3) ◽  
pp. 406-414
Author(s):  
Eduarda da Silva Belloni ◽  
Fernanda Mazuco Clain ◽  
Carlos Eduardo Marcos Guilherme
Keyword(s):  
Structural Integrity ◽  
Breaking Load ◽  
Sem Analysis ◽  
Axial Loads ◽  
Creep Tests ◽  
Tensile Fatigue ◽  
Before And After ◽  
Post Impact ◽  
The Impact

The present work evaluates the mechanical behaviour of High Modulus Polyethylene (HMPE) yarns after being impacted by sudden axial loads. The influence of loading conditions on the structural integrity of yarns is assessed by tensile, fatigue, and creep tests before and after the impact events. The impact loads were inferred by drop-weight adopting a 300mm height and weights corresponding to 4, 5, and 6% of Yarn Breaking Load (YBL). At 5% YBL, most specimens fail after the impact, and at 6% YBL, all specimens fail. The application of 4% YBL tests results in enhanced creep and fatigue resistances and a decrease in the tensile resistance. Finally, a Scanning Electron Microscopy (SEM) analysis showed that the yarn filaments tend to straighten after the impact, while a decrease in their diameter is noticed due to the longitudinal deformation.

scholarly journals Importance of physiotherapy/nursing multidisciplinary integration about update newborn position in the neonatal intensive care unit

2015 ◽  
Vol 28 (3) ◽  
pp. 437-445 ◽  
Author(s):  
Vanessa da Silva Neves Moreira Arakaki ◽  
Alana Monteiro de Oliveira ◽  
Trícia Bogossian ◽  
Viviane Saraiva de Almeida ◽  
Gustavo Dias da Silva ◽  
...  
Keyword(s):  
Intensive Care ◽  
Neonatal Intensive Care ◽  
Physical Therapist ◽  
Body Position ◽  
Effective Care ◽  
Before And After ◽  
Student’S T ◽  
The Impact ◽  
Clinical Stability

AbstractIntroduction The high-risk newborns may require long periods of hospitalization until they reach clinical stability for hospital discharge. Avoiding babies to be in only one body position may be an effective way to cause respiratory and neuro-psycho-motor benefits, comfort and preventing pressure ulcers.Objectives This study investigated the impact of physiotherapy/nursing integration in update on body positioning of the newborn in the Neonatal Intensive Care Unit.Methods A questionnaire was administered to nurses and nursing technicians of the neonatal unit of Maternity School of UFRJ and nurses of the Advanced Course in Neonatal Nursing from the same institution. Two classes were taught by the physical therapist of the sector and the questions answered before and after these lessons. It was also a brief characterization of professional participants of the study. We used the Student's t test to compare the correct answers before (PRE) and after (POST) the classes, considering p < 0.05.Results There was a significant increase in the degree of knowledge of nurses and nursing technicians when compared the responses before (nurses: 68.8%; technicians: 70.1%) and after classes (nurses: 78.4 %; technicians: 88.9%). The nurses were less than five years of graduated (45%) and little time of professional experience in neonatology (60%). Forty-seven percent of technicians had less than five years of training and 82% had less than 10 years of experience.Conclusion The use of training by the nursing staff was significant, showing the importance of multidisciplinary approach and the integration of knowledge in the search for a humanized and effective care.

scholarly journals Microstructural Characterization of Antimony Modified Carbidic Austempered Ductile Iron

2019 ◽  
Vol 8 (2) ◽  
pp. 36
Author(s):  
Abel. A. Barnabas ◽  
Akinlabi Oyetunji ◽  
S. O. Seidu
Keyword(s):  
Ductile Iron ◽  
Microstructural Characterization ◽  
Sem Analysis ◽  
Austempered Ductile Iron ◽  
Carbide Formation ◽  
Primary Carbide ◽  
Chunky Graphite ◽  
High Level ◽  
The Impact

In this research, Scanning Electron Microscope (SEM) analysis was conducted on the produced antimony modified carbidic austempered ductile iron for agricultural implement production. Six different alloys of carbidic austempered ductile iron with varying micro quantities of antimony elements were produced. The produced alloys were heated to austenitic temperature of 910oC, held at this temperature for 1 hour, finally subjected to austempering temperatures of 300&deg;C and 325&deg;C for periods of 1-3 hours. The SEM in conjunction with XRD and EDS was used for the analysis. Microstructural phase morphology, phase constituents and phase compositions were viewed with SEM, XRD and EDS respectively. The results show that various phases such as spiky graphite, blocky carbides, granular carbide, pearlite and ausferrite matrix. The XRD pattern revealed some compounds such as (Fe, Cr)3C, (primary carbide), Cr6C23 (few secondary carbide), (NiFe2O4), chromite (FeCr2O4), Cr7C3 (few eutectic carbide) and Cr3Ni2. In conclusion, it was observed in terms of morphology that chunky graphite, blocky carbide and pearlite phases were present in the cast carbidic ductile iron (CDI) without antimony addition. The CDI with varying quantities of antimony additions shows spiky graphite, granular carbides and pearlite matrix. After the samples were subjected to austempering processes, all the phases were found to be intact except the pearlite phase that transformed to ausferrite phase. The antimony element in the alloys was seen to promote the formation of pearlite phase intensively. The hardness of the samples increases as the antimony addition increases from 0.096wt.% to 0.288wt.% owing to the increase in pearlite phase, while the impact toughness reaches relatively high level, when 0.288wt.% antimony was added, probably due to the refinement of graphite nodules. All the results obtained showed that appropriate content of antimony addition plays an important role in increasing the nucleation rate of graphite nodules, and also lead to improvement in carbide formation thereby providing good balance between wear and impact properties.

scholarly journals Assessment of the Impact of Stagnation Temperatures in Receiver Prototypes of C-PVT Collectors

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2967 ◽  
Author(s):  
João Gomes
Keyword(s):  
Solar Cells ◽  
Thermal Stress ◽  
Structural Integrity ◽  
Heat Transfer Fluid ◽  
Strain Relief ◽  
Prototype Test ◽  
Before And After ◽  
And Performance ◽  
Initial Power ◽  
The Impact

Concentrating Photovoltaic Thermal (C-PVT) solar collectors produce both thermal and electric power from the same area while concentrating sunlight. This paper studies a C-PVT design where strings of series-connected solar cells are encapsulated with silicone in an aluminium receiver, inside of which the heat transfer fluid flows, and presents an evaluation on structural integrity and performance, after reaching stagnation temperatures. Eight test receivers were made, in which the following properties were varied: Size of the PV cells, type of silicone used to encapsulate the cells, existence of a strain relief between the cells, size of the gap between cells, and type of cell soldering (line or point). The test receivers were placed eight times in an oven for one hour at eight different monitored temperatures. The temperature of the last round was set at 220 °C, which exceeds the highest temperature the panel design reaches. Before and after each round in the oven, the following tests were conducted to the receivers: Electroluminescence (EL) test, IV-curve tracing, diode function, and visual inspection. The test results showed that the receivers made with the transparent silicone and strain relief between cells experienced less microcracks and lower power degradation. No prototype test receiver lost more than 30% of its initial power, despite some receivers displaying a large number of cell cracks. The transparent and more elastic silicone is better at protecting the solar cells from the mechanical stress of thermal expansion than the compared silicone alternative, which was stiffer. As expected, larger cells are more prone to develop microcracks after exposure to thermal stress. Additionally, existing microcracks tend to grow in size relatively fast under thermal stress. EL imaging taken during our experiment leads us to conclude that it is far more likely for existing cracks to expand than for new cracks to appear.

scholarly journals Design of an Innovative Test Rig for Industrial Bearing Monitoring with Self-Balancing Layout

Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Eugenio Brusa ◽  
Cristiana Delprete ◽  
Lorenzo Giorio ◽  
Luigi Gianpio Di Maggio ◽  
Vittorio Zanella
Keyword(s):  
Industrial Applications ◽  
The Novel ◽  
Axial Loads ◽  
Test Rig ◽  
System Failures ◽  
Novel Concept ◽  
Time Required ◽  
The Impact ◽  
Bearing Monitoring

The remote prognosis and diagnosis of bearings can prevent industrial system failures, but the availability of realistic experimental data, being as close as possible to those detected in industrial applications, is essential to validate the monitoring algorithms. In this paper, an innovative bearing test rig architecture is presented, based on the novel concept of “self-contained box”. The monitoring activity is applicable to a set of four middle-sized bearings simultaneously, while undergoing the independent application of radial and axial loads in order to simulate the behavior of the real industrial machinery. The impact of actions on the platform and supports is mitigated by the so-called “self-contained box” layout, leading to self-balancing of actions within the rotor system. Moreover, the high modularity of this innovative layout allows installing various sized bearings, just changing mechanical adapters. This leads to a reduction of cost as well as of system down-time required to change bearings. The test rig is equipped with suitable instrumentation to develop effective procedures and tools for in- and out-monitoring of the system. An initial characterization of the healthy system is presented.

Microstructural and mechanical characterization of the effect of the welding process on creep behavior of welded joint and base metal specimens of Inconel 600

MRS Advances ◽  
2020 ◽  
Vol 5 (59-60) ◽  
pp. 3003-3014
Author(s):  
Lourdes Y. Herrera-Chávez ◽  
Alberto Ruiz ◽  
Víctor H. López-Morelos ◽  
Carlos Rubio-González ◽  
Martín R. Barajas-Álvarez ◽  
...  
Keyword(s):  
Base Metal ◽  
Creep Behavior ◽  
Heat Affected Zone ◽  
Structural Integrity ◽  
Welded Joint ◽  
Welding Process ◽  
Creep Tests ◽  
Inconel 600 ◽  
Two Temperatures

AbstractIn this study, plates of Inconel 600 superalloy were gas metal arc welded to investigate the effects of the welding process on the creep behavior of the welded samples and compare it to the creep behavior of samples in the as-received condition. Creep tests were performed at two temperatures (600 and 650 °C) with different stress levels. During the welding process, three distinctive microstructural zones are generated, i.e. welded material, heat affected zone, and base metal that may affect the properties of the welded joint. Microstructural, elemental analysis of samples was conducted using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS). The experimental results show that creep rupture preferentially occurs in the heat-affected zone of the base metal at 4 mm from the fusion line and that the creep behavior of welded samples is different from that of the base metal. These results can be used in the design of structural components to assure their structural integrity.

Linking the Impact Force History with Residual Mechanical Characteristics and NDI - A Smart Way to Perform SHM in Composites

2008 ◽  
Vol 56 ◽  
pp. 524-529 ◽  
Author(s):  
Nicolae Constantin ◽  
Viorel Anghel ◽  
Mircea Găvan ◽  
Ştefan Sorohan
Keyword(s):  
Composite Materials ◽  
Mechanical Characteristics ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Impact Force ◽  
Layered Composite ◽  
Damage Level ◽  
Clear Link ◽  
Post Impact ◽  
The Impact

Structural integrity monitoring (SHM) and evaluation of residual mechanical performance are highly needed in assessing the post-impact behaviour of composite materials and structures. The link between impact force history and the damage level was not followed enough in research studies upon the SHM of composites. The authors put in evidence a clear link in this matter in a variety of layered composite materials. The link was assessed by evaluating the residual mechanical performance and by nondestructive inspection (NDI) – ultrasonics and infrared thermography (IRT) - on the impacted samples. Such a link may prove a very useful and reliable shortcut for backing the online SHM and condition based maintenance.

scholarly journals Synthesis and Characterization of Chitosan Linked by Methylene Bridge and Schiff Base of 4,4-Diaminodiphenyl Ether-Vanillin

2018 ◽  
Vol 18 (1) ◽  
pp. 92 ◽  
Author(s):  
Ahmad Fatoni ◽  
Poedji Loekitowati Hariani ◽  
Hermansyah Hermansyah ◽  
Aldes Lesbani
Keyword(s):  
Schiff Base ◽  
Functional Group ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Casting Method ◽  
Azomethine Group ◽  
Methylene Bridge ◽  
Modified Chitosan ◽  
Before And After

The synthesis chitosan-methylene bridge-Schiff base of 4,4-diaminodiphenyl ether-vanillin using casting method has been done. The aims of this research were modification chitosan with Schiff base of 4,4-diaminodiphenyl ether-vanillin, formaldehyde and its characterization using FTIR spectroscopy, SEM analysis, 1H-NMR and X-Ray Diffraction analysis. The first step was a synthesis of modified chitosan between chitosan and Schiff base of 4,4-diaminodiphenyl ether-vanillin. The second step was chitosan modified Schiff base of 4,4-diaminodiphenyl ether-vanillin then reacted with formaldehyde through casting method. The result showed that chitosan can be modified with Schiff base of 4,4-diaminodiphenyl ether-vanillin and formaldehyde and this modified chitosan can be linked by methylene bridge (-NH-CH2-NH-) and had azomethine group (-C=N-). The functional group of –C=N in modified chitosan before and after adding formaldehyde appeared at a constant wavenumber of 1597 cm-1. The functional group C-N in methylene bridge detected at 1388 and 1496 cm-1. The chitosan-Schiff base of 4,4-diaminodiphenyl ether-vanillin and Chitosan-methylene bridge-Schiff base of 4,4-diaminodiphenyl ether-vanillin had index crystalline (%)16.04 and 25.76, respectively. The chemical sift of signal proton azomethine group (-C=N-) in modified chitosan detected at 8.44–8.48 and 9.77 ppm. Proton from methylene bridge in modified chitosan appeared at 4.97–4.99 and 3.75 ppm. Surface morphology chitosan-methylene bridge-Schiff base of 4,4-diaminodiphenylether-vanillin had dense surfaces, mostly uniform and regular in shape.

scholarly journals Potential Peat Clay for Minerals Source Utilized as Adsorbent and Catalyst

2019 ◽  
Vol 280 ◽  
pp. 04003
Author(s):  
Agus Mirwan ◽  
Meilana Dharma Putra ◽  
Riani Ayu Lestari
Keyword(s):  
Xrd Analysis ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Huge Amount ◽  
Calcination Process ◽  
X Ray ◽  
Potential Source ◽  
Before And After ◽  
Flake Structure

The existence of peat clay is scattered in many parts of the world with the huge amount. The high compound of minerals in the peat clay can be potentially used as adsorbent and catalyst. This research aims to study the composition of peat clay and functional group of the compound in the peat clay. The characterization of x-ray fluorescence (XRF), fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and scanning electron microscope-energy dispersive x-ray (SEM- EDX) were assigned to compare the sample before and after calcination process at 700 oC 120 min. FTIR analysis showed the presence of quartz, kaolinite, hematite, illite in peat clay. The results of XRF analysis showed that chemical composition of peat clay was dominantly in the form of silica oxide (18%), aluminum oxide (7%), and iron oxide (15%). The amount of compounds was observed to increase to be 32%, 18% and 11%, respectively after calcinations. XRD analysis confirmed the presence of this mineral in the peat clay. SEM analysis showed flake structure of peat clay with EDX which indicated composition of the dominant element namely the presence of Al, Si, and Fe before and after calcination. This high amount of minerals in peat clay led to potential source to be utilized as adsorbent for removing the pollutant or as and catalyst for chemical process.

The Impact of Corrosion on the Mechanical Behavior of Bolt

2010 ◽  
Vol 168-170 ◽  
pp. 408-411
Author(s):  
Xiao Yong Li
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Corrosion Test ◽  
Laboratory Tests ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Rock Bolt ◽  
Before And After ◽  
The Impact ◽  
Strength And Ductility

Corrosion is a negative contributor on the structural integrity of rock bolt and leads to degradation of the mechanical properties of steel rock bolt. Exposure to chloride, seawater, salt and saltwater and deicing chemical environments influences rock bolt and weakens it. In order to evaluate the influence of corrosion and the size of the steel on the mechanical properties of rock bolt, an experimental investigation was conducted on rock bolt whose rebar is 8, 12, 16, and 18 mm diameter, and which were artificially corroded for 10, 20, 30, 45, 60, 90, and 120 days. By the simulation corrosion test of loaded and unloaded bolts in Na2SO4 solution, the relation curves of the mechanical performance with the corrosive conditions and the corrosion time are given. The mechanical performance is compared between these two types of bolts. At the same time, the influential trend of the load on the mechanical performance of the corroded bolt is analyzed. The laboratory tests suggest that corrosion duration and rebar size had a significant impact on the strength and ductility degradation of the specimens. after being corroded in Na2SO4 solution, both the ultimate bearing capacity and the maximal tensility of loaded bolt decrease far more than those of unloaded bolt, and the endurance and service life of loaded bolt will also be shortened much more severely. The tensile mechanical properties before and after corrosion indicated progressive variation and drastic drop in their values.

scholarly journals Detecting the antibacterial activity of green synthesized silver (Ag) nanoparticles functionalized with ampicillin (Amp)

2017 ◽  
Vol 14 (1) ◽  
pp. 117-125
Author(s):  
Baghdad Science Journal
Keyword(s):  
Antibacterial Activity ◽  
Zeta Potential ◽  
Growth Medium ◽  
Sem Analysis ◽  
Culture Solution ◽  
Agno3 Solution ◽  
Vis Spectroscopy ◽  
Before And After ◽  
Zones Of Inhibition

In the current study, synthesis and characterization of silver nanoparticles (AgNPs) before and after functionalization with ampicillin antibiotic and their application as anti-pathogenic agents towards bacteria were investigated. AgNPs were synthesized by a green method from AgNO3 solution with glucose subjected to microwave radiation. Characterization of the nanoparticles was conducted using UV-Vis spectroscopy, scanning electron microscopy (SEM), zeta potential determination and Fourier transform infrared (FTIR) spectroscopy. From SEM analysis, the typical silver nanoparticle particle size was found to be 30 nm and Zeta potential measurements gave information about particle stability. Analysis of FTIR patterns and UV-VIS spectroscopy confirmed the production of nanosilver particles. The activity of produced silver NP was tested against three pathogens (Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii) in both liquid and solid growth medium. AgNPs presented potential antibacterial activity, against tested bacteria. Ag and Ag-AMP nanoparticles were detected to have penitent antimicrobial. The optical density (OD) of the culture solution and measuring zones of inhibition were used to monitor the growth of bacteria in liquid and solid growth medium respectively

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