scholarly journals Investigations on corrosion and mechanical properties of a 20 year old ground anchor exhumed at a power station site

2016 ◽  
Vol 53 (4) ◽  
pp. 589-602 ◽  
Author(s):  
Yujie Wang ◽  
Aiwu Ren ◽  
Yanshu Wang ◽  
Jiquan He ◽  
Zuyu Chen
Keyword(s):  
Mechanical Test ◽  
Test Procedure ◽  
Test Results ◽  
X Ray Diffraction ◽  
Tunnel Face ◽  
Bonding Force ◽  
Laboratory Test Results ◽  
Average Corrosion Rate ◽  
Chinese Standard ◽  
Gradual Release

This paper presents the observed findings and laboratory test results of an anchor exhumed from Manwan Hydropower Station, China, that was installed 20 years ago. The prestressed cables are 25.6 m long with a working load of 1000 kN. It consists of eight strands, and each strand consists of seven wires. The anchor was installed using the “single protection” technique (i.e., the steel strands without greased sheath and were backfilled directly with cement mortar). The anchor was unearthed by excavating a 1.5 m × 1.7 m tunnel. Visual inspection shows that the steel strands in the free and fixed lengths are basically stainless except for a few places where the grout failed to cover the anchor completely, thereby allowing direct contact of the strands with air. The magnitude of rebound of the tendon during the advancement of the tunnel face was simultaneously measured indicating a gradual release of bonding force, which was up to 62% of the prestressed load. This shows that the existence of the bonding force is provided by the bonding between the strand and the grout, while this bonding does not exist in the “double protection” system. The results of the mechanical test confirm that the tensile strengths in all the 33 steel wires exceed the requirement as specified by a current Chinese Standard. The concentrations of various chemicals also satisfy the requirements as specified by the China State Bureau of Quality Technical Supervision. The results of the X-ray diffraction test show that the stains taken from the surface of the strand are composed of FeO and FeOOH, both being oxide products of iron. This shows that exposure of the material to air is an important condition to initiate corrosion. By following the ASTM International G1-03 test procedure, the average corrosion rate is found to be between 3 × 10−4 and 6 × 10−4 mm/year. This investigation generally supports the use of unprotected steel strands in rock anchor.

Transient liquid phase bonding of Cu and Al using metallic particles interlayers

2021 ◽  
pp. 095440542098823
Author(s):  
Alireza Zaheri ◽  
Mohammadreza Farahani ◽  
Alireza Sadeghi ◽  
Naser Souri
Keyword(s):  
Liquid Phase ◽  
Mechanical Test ◽  
Transient Liquid Phase ◽  
Transient Liquid Phase Bonding ◽  
Joint Interface ◽  
Test Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metallic Particles ◽  
Powder Interlayer

The bonding strength, and microstructures of Cu and Al couples using metallic powders as interlayer during transient liquid phase bonding (TLP bonding) were investigated. The interfacial morphologies and microstructures were studied by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, and X-ray diffraction. First, to explore the optimum bonding time and temperature, nine samples were bonded without interlayers in a vacuum condition. Mechanical test results indicated that bonding at 560°C in 20 min returns the highest bond strength (84% of Al). This bonding condition was used to join ten samples with powder interlayers. Powders were prepared by mixing different combinations of Cu, Al (+Fe nanoparticles) and Zn. In the bonding zone, different Cu9Al4, CuAl, and CuAl2 intermetallic co-precipitate. The strongest bonding is formed in the sample with the 70Al (+Fe)-30Cu powder interlayer. Powder interlayers present thinner and more uniform intermetallic layers at the joint interface.

scholarly journals Natural Mordenite from Spain as Pozzolana

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1220
Author(s):  
Leticia Presa ◽  
Jorge L. Costafreda ◽  
Domingo A. Martín ◽  
Isabel Díaz
Keyword(s):  
Mechanical Test ◽  
Low Cost ◽  
Principal Component ◽  
Test Results ◽  
Mechanical Compression ◽  
San Jose ◽  
X Ray Diffraction ◽  
Pozzolanic Cement ◽  
Natural Clinoptilolite ◽  
Potential Use

This work deals with anomalous concentrations of natural mordenite in the southeast of Spain. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies evidenced that the samples contain mainly monomineral zeolitic phase of mordenite (70% to 74%), usually accompanied by smectite (montmorillonite), the principal component of bentonite. A study of the applicability of these zeolites is presented to establish the potential use as pozzolanic cements. For comparative purposes, synthetic commercial mordenite is also characterized and tested. The initial mixtures were prepared using cement and mordenite at a 75:25 ratio. Chemical analysis and a pozzolanicity test showed the high pozzolanic character. These mixtures were further added to sand and water, yielding the cement specimens to be used as concrete. Mechanical test results showed that the mechanical compression at 7 and 28 days fall into the range of 19.23 to 43.05 MegaPascals (MPa) for the cement specimens built with natural mordenites. The obtained results fall in the same range of cement specimens prepared with natural clinoptilolite, using mixtures within the European requirement for commercial concretes. Thus, these results and the low cost of natural mordenite of San José de los Escullos deposit supports the potential use of natural mordenite as pozzolanic cement.

scholarly journals Investigation effect of depressant additives on physicochemical properties of engine oil

2021 ◽  
pp. 30-34
Author(s):  
S. V. Pashukevich ◽  
Keyword(s):  
Pour Point ◽  
Combustion Engine ◽  
Test Procedure ◽  
Engine Oil ◽  
Base Number ◽  
Test Results ◽  
Corrosion Properties ◽  
Engine Oils ◽  
Laboratory Test Results ◽  
Tractor Engine

In this work, laboratory tests of M8G2k engine oil are carried out with the introduction of SAP 110 depressants by Shell Additives and Lz 6662 by Lubrizol and their impact on the properties of the lubricant in question are assessed separately. During the tests, the values of the following indicators of engine oils are obtained: kinematic viscosity at 100 °C, base number, flash point in an open crucible, pour point and content of active elements (calcium, zinc). With the help of the SI-010 bench installation, the values of anti-pitting properties are indicated, as well as experiments are carried out on the NAMI-1m and Petter W-1 installations, with their help the tendency to the formation of low- and high-temperature deposits in the internal combustion engine (ICE) and the assessment of anti-corrosion properties respectively. To analyze the detergent properties of the engine oil under consideration, a test procedure are carried out on a D-240 tractor engine. Positive laboratory test results give grounds to recommend using M8G2k engine oil containing SAP 110 or Lz 6662 additives for the D-240 engine manufactured by MMZ

scholarly journals Reinforcing Linear Low-Density Polyethylene with Surfactant-Treated Microfibrillated Cellulose

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 441 ◽  
Author(s):  
Guangzhao Wang ◽  
Xiaohui Yang ◽  
Weihong Wang
Keyword(s):  
Mechanical Properties ◽  
Composite Film ◽  
Mechanical Test ◽  
Intermolecular Hydrogen Bond ◽  
Microfibrillated Cellulose ◽  
Light Transmittance ◽  
Test Results ◽  
X Ray Diffraction ◽  
Twin Screw ◽  
Ldpe Composites

Due to its excellent mechanical properties and reinforcement abilities, cellulose has become a promising candidate for developing nanocomposites. However, cellulose agglomeration is an issue that must be solved. In this study, we treated microfibrillated cellulose (MFC) with a mixture of the non-ionic surfactants Span80 and Tween80 (ratio of 1:1) in order to prevent the intermolecular hydrogen bond aggregation of MFC during the process of MFC drying. We used a conical twin-screw extruder to melt compounds for the surfactant-treated MFC and powdered LLDPE. Furthermore, the extruded mixture was hot-pressed into a film, and we also tested the properties of the composite film. We can conclude that there was no agglomeration in the composite film according to microscopic observations and light transmittance test results. Furthermore, the dispersion of the surfactant-treated MFC (STMFC) was uniform until the STMFC filler increased to 10 wt%. The mechanical test results show that when the content of STMFC filler was 10 wt%, the mechanical properties of the composite were optimal. Compared to LLDPE, the STMFC/LLDPE composite film had an increase of 41.03% in tensile strength and an increase of 106.35% in Young’s modulus. Under this system, the DSC results show that the melting point of LLDPE increased from 125 to 131 °C. X-ray diffraction (XRD) results showed that the addition of STMFC did not change the crystallinity of the STMFC/LDPE composites, although the crystallite size increased.

Effect of Ibuprofen on Serum Laboratory Test Results

1983 ◽  
Vol 40 (6) ◽  
pp. 1025-1034
Author(s):  
Carol L. Colvin ◽  
Raymond J. Townsend ◽  
William R. Gillespie ◽  
Kenneth S. Albert
Keyword(s):  
Laboratory Test ◽  
Test Results ◽  
Laboratory Test Results

scholarly journals Performance Study of Grass-Derived Nano-Cellulose and Polycaprolactone Composites for 3D Printing

2021 ◽  
Vol 11 (3) ◽  
pp. 1273
Author(s):  
Chen Feng ◽  
Jiping Zhou ◽  
Xiaodong Xu ◽  
Yani Jiang ◽  
Hongcan Shi ◽  
...  
Keyword(s):  
3D Printing ◽  
Mechanical Test ◽  
Chemical Properties ◽  
Test Results ◽  
Performance Study ◽  
Compression Process ◽  
Ansys Fluent ◽  
Nano Cellulose ◽  
Physical And Chemical ◽  
And Chemical Properties

In recent years, 3D printing has received increasing attention from researchers. This technology overcomes the limitations of traditional technologies by printing precise and personalized scaffold with arbitrary shapes, pore structures, and porosities for the applications in various tissues. The cellulose nanocrystal (CNC) is extracted from Humulus Japonicus (HJS) and mixed with poly(ε-caprolactone) (PCL) to prepare a series of CNC/PCL composites for printing. Based on the analysis of the physical and chemical properties of the series of the CNC/PCL composites, an optimal mass ratio of CNC to PCL was obtained. The Solidworks was used to simulate the stretching and compression process of the scaffolds with three different patterns under an external force. The flow of nutrient solution in the scaffolds with different patterns was simulated by ANSYS FLUENT, and then a new optimization scaffold pattern with a concave hexagon shape was advised based on the simulation results. Collectively, the mechanical test results of the material and scaffold confirmed that the optimal filling amount of the CNC was 5%, and the scaffold pattern with concave hexagon shape exhibited better mechanical properties and suitable for the transport of cells and nutrients, which is expected to be more widely used in 3D printing.

Quality benchmarking of smartphone laboratory medicine applications: comparison of laboratory medicine specialists’ and non-laboratory medicine professionals’ evaluation

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Snežana Jovičić ◽  
Joanna Siodmiak ◽  
Marta Duque Alcorta ◽  
Maximillian Kittel ◽  
Wytze Oosterhuis ◽  
...  
Keyword(s):  
Information Quality ◽  
Rating Scale ◽  
Laboratory Medicine ◽  
Test Results ◽  
Content Quality ◽  
Laboratory Test Results ◽  
System Usability Scale ◽  
Mobile Health Applications ◽  
Fit For Purpose ◽  
Health Applications

AbstractObjectivesThere are many mobile health applications (apps) now available and some that use in some way laboratory medicine data. Among them, patient-oriented are of the lowest content quality. The aim of this study was to compare the opinions of non-laboratory medicine professionals (NLMP) with those of laboratory medicine specialists (LMS) and define the benchmarks for quality assessment of laboratory medicine apps.MethodsTwenty-five volunteers from six European countries evaluated 16 selected patient-oriented apps. Participants were 20–60 years old, 44% were females, with different educational degrees, and no professional involvement in laboratory medicine. Each participant completed a questionnaire based on the Mobile Application Rating Scale (MARS) and the System Usability Scale, as previously used for rating the app quality by LMS. The responses from the two groups were compared using the Mann-Whitney U test and Spearman correlation.ResultsThe median total score of NLMP app evaluation was 2.73 out of 5 (IQR 0.95) compared to 3.78 (IQR 1.05) by the LMS. All scores were statistically significantly lower in the NLMP group (p<0.05), except for the item Information quality (p=0.1631). The suggested benchmarks for a useful appear: increasing awareness of the importance and delivering an understanding of persons’ own laboratory test results; understandable terminology; easy to use; appropriate graphic design, and trustworthy information.ConclusionsNLMP’ evaluation confirmed the low utility of currently available laboratory medicine apps. A reliable app should contain trustworthy and understandable information. The appearance of an app should be fit for purpose and easy to use.

scholarly journals COVID-19 and pregnancy – where are we now? A review

2020 ◽  
Vol 48 (5) ◽  
pp. 428-434 ◽  
Author(s):  
Aleksandra Rajewska ◽  
Wioletta Mikołajek-Bedner ◽  
Joanna Lebdowicz-Knul ◽  
Małgorzata Sokołowska ◽  
Sebastian Kwiatkowski ◽  
...  
Keyword(s):  
Case Fatality ◽  
Fetal Distress ◽  
Delivery Mode ◽  
Test Results ◽  
Rt Pcr ◽  
Third Trimester ◽  
The Third ◽  
Laboratory Test Results ◽  
Protective Antibodies ◽  
Polymerase Chain

AbstractThe new acute respiratory disease severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is highly contagious. It has caused many deaths, despite a relatively low general case fatality rate (CFR). The most common early manifestations of infection are fever, cough, fatigue and myalgia. The diagnosis is based on the exposure history, clinical manifestation, laboratory test results, chest computed tomography (CT) findings and a positive reverse transcription-polymerase chain reaction (RT-PCR) result for coronavirus disease 2019 (COVID-19). The effect of SARS-CoV-2 on pregnancy is not already clear. There is no evidence that pregnant women are more susceptible than the general population. In the third trimester, COVID-19 can cause premature rupture of membranes, premature labour and fetal distress. There are no data on complications of SARS-CoV-2 infection before the third trimester. COVID-19 infection is an indication for delivery if necessary to improve maternal oxygenation. Decision on delivery mode should be individualised. Vertical transmission of coronavirus from the pregnant woman to the fetus has not been proven. As the virus is absent in breast milk, the experts encourage breastfeeding for neonatal acquisition of protective antibodies.

scholarly journals Atypical anti-glomerular basement membrane disease with anti-GBM antibody negativity and ANCA positivity: a case report

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Na Guo ◽  
Qinghua Yin ◽  
Song Lei ◽  
Yanjun He ◽  
Ping Fu
Keyword(s):  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Rare Case ◽  
Test Results ◽  
Serum Samples ◽  
Tissue Samples ◽  
Case Presentation ◽  
Severe Renal Insufficiency ◽  
Laboratory Test Results ◽  
Organ Specific

Abstract Background Anti-glomerular basement membrane (anti-GBM) disease is an organ-specific autoimmune disease that involves the lung and kidneys and leads to rapid glomerulonephritis progression, with or without diffuse alveolar hemorrhage, and even respiratory failure. Classic cases of anti-GBM disease are diagnosed based on the presence of the anti-GBM antibody in serum samples and kidney or lung biopsy tissue samples. However, atypical cases of anti-GBM disease are also seen in clinical practice. Case presentation We herein report the rare case of a patient with atypical anti-GBM disease whose serum was negative for the anti-GBM antibody but positive for the myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibody (p-ANCA) and another atypical ANCA. Laboratory test results showed severe renal insufficiency with a creatinine level of 385 μmol/L. Renal biopsy specimen analysis revealed 100% glomeruli with crescents; immunofluorescence showed immunoglobulin G (IgG) linearly deposited alongside the GBM. Finally, the patient was discharged successfully after treatment with plasmapheresis, methylprednisolone and prednisone. Conclusion This patient, whose serum was negative for the anti-GBM antibody but positive for p-ANCA and another atypical ANCA, had a rare case of anti-GBM disease. Insights from this unusual case might help physicians diagnose rare forms of glomerulonephritis and treat affected patients in a timely manner.

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