Model Tests for Evaluating the Impact of Low Viscosity Tailor-Made Biofuels on Tribological Contacts in Injection Pumps

2013 ◽  
Author(s):  
Stefan Heitzig ◽  
Alexander Weinebeck ◽  
Hubertus Murrenhoff
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
Research Approach ◽  
Low Viscosity ◽  
Injection Pump ◽  
The Impact ◽  
Fuel Lubricity

In the scope of the cluster of excellence “Tailor-made Fuels from Biomass” new biofuels are developed within an interdisciplinary research approach at RWTH Aachen University. To ensure a safe and reliable functioning of the new fuels in combination with state of the art fuel injection equipment, every fuel has to fulfil requirements regarding its tribological performance, which depends on characteristics like dynamic viscosity and fuel lubricity. Hence, one focus of the cluster lies on the tribological characteristics of the fuel candidates. Biofuel candidates which have been investigated so far and which are suitable for the use in self-ignition engines as surrogates for fossil diesel fuel tend to have lower viscosities and show varying lubrication behaviour, compared to diesel. As a standard test method for diesel fuel lubricity the HFRR test is well established. Nevertheless, relying on the established diesel-pass/fail criterion, which is defined in several norms, is disputable, since the investigated biofuels differ strongly from modern diesel fuels. To identify the relevant fuel properties and to gain a more detailed understanding of the wear and friction processes within the critical contacts, results of different tribological test methods, including the HFRR test and a disc-on-disc tribometer, are presented, compared and discussed in this paper. In order to estimate the validity of the established HFRR pass/fail criterion for low viscosity biofuels the experimental results are compared to simulation outcomes of elasto-hydrodynamic simulations of the main tribological contacts in a standard common rail injection pump.

The Influence of Turbulence (or Hydrodynamic Effects) on Strontium Sulphate Scale Formation and Inhibitor Performance

2014 ◽  
Author(s):  
Clare Johnston ◽  
Louise Sutherland
Keyword(s):  
Barium Sulphate ◽  
Test Methods ◽  
Standard Test ◽  
Field Application ◽  
Scale Formation ◽  
Test Method ◽  
Scale Inhibitor ◽  
Modified Method ◽  
Bottle Test ◽  
The Impact

Abstract Inorganic scale (carbonate, sulphate and sulphides) formation can be predicted from thermodynamic models and over recent years better kinetic data has improved the prediction of such scales in field conditions. However these models have not been able to predict the observed deposition where flow disturbances occur, such as at chokes, tubing joints, gas lift valves and safety valves. This can lead to unexpected failures of critical equipment such as downhole safety valves (DHSV’s), and operational issues such as failure to access the well for coiled tubing operations due to tubing restrictions. In recent years it has been recognised that the turbulence found at these locations increases the likelihood of scale formation and experiments have been able to demonstrate that increased turbulence also impacts the minimum scale inhibitor concentration required to prevent scale. One of the industry standard test methods used to screen inhibitors for sulphate scale inhibition is the static bottle test. In this paper the ‘static’ bottle test method is modified to investigate the effects of increasing levels of turbulence on the formation of strontium sulphate scale at a fixed brine composition. Using this modified method it has been possible to demonstrate the impact of varying turbulence on the performance of two common generic types of scale inhibitor (phosphonate and vinyl sulphonate co-polymer). Data on the mass of scale formed, scale morphology using SEM imaging and inhibitor efficiency will be linked to degree of turbulence and scale inhibitor functionality (nucleation inhibition vs. crystal growth retardation). This study builds on the previously published10 findings for barium sulphate which showed phosphonates were less affected by turbulent conditions by carrying out similar tests on strontium sulphate. A clear mechanistic conclusion can now be drawn for sulphate scale formation and inhibition under increasingly turbulent conditions. The findings from this study have a significant impact on the methods of screening scale inhibitors for field application that should be utilised and development of suitable inhibitors that perform better under higher shear conditions.

Round-Robin of High-Frequency Test Methods by IPC-D24C Task Group

2016 ◽  
Vol 13 (3) ◽  
pp. 77-94
Author(s):  
Glenn Oliver ◽  
Jonathan Weldon ◽  
Chudy Nwachukwu ◽  
John Andresakis ◽  
John Coonrod ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
High Frequency ◽  
High Speed ◽  
Test Methods ◽  
Round Robin ◽  
Standard Test ◽  
Test Method ◽  
Task Group ◽  
Circuit Board ◽  
Industry Standard

Currently, there is no industry standard test method for measuring dielectric properties of circuit board materials at frequencies greater than ~10 GHz. Various material vendors and test laboratories apply different approaches to determine these properties. It is common for these different approaches to yield varying values of key properties such as permittivity and loss tangent. The D-24C Task Group of IPC has developed this round-robin program to assess these various methods from the “bottom up” to determine if standardized methods can be agreed upon to provide the industry with more accurate and valid characteristics of dielectrics used in high-frequency and high-speed applications.

scholarly journals An Innovative Test Method for Tensile Strength of Concrete by Applying the Strut-and-Tie Methodology

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2776 ◽  
Author(s):  
Wen-Cheng Liao ◽  
Po-Shao Chen ◽  
Chung-Wen Hung ◽  
Suyash Kishor Wagh
Keyword(s):  
Tensile Strength ◽  
Test Methods ◽  
Standard Test ◽  
Strength Test ◽  
Tension Test ◽  
Test Method ◽  
Direct Tension ◽  
Direct Tension Test ◽  
Strut And Tie ◽  
Tensile Strength Test

Tensile strength is one of the important mechanical properties of concrete, but it is difficult to measure accurately due to the brittle nature of concrete in tension. The three widely used test methods for measuring the tensile strength of concrete each have their shortcomings: the direct tension test equipment is not easy to set up, particularly for alignment, and there are no standard test specifications; the tensile strengths obtained from the test method of splitting tensile strength (American Society for Testing and Materials, ASTM C496) and that of flexural strength of concrete (ASTM C78) are significantly different from the actual tensile strength owing to mechanisms of methodologies and test setup. The objective of this research is to develop a new concrete tensile strength test method that is easy to conduct and the result is close to the direct tension strength. By applying the strut-and-tie concept and modifying the experimental design of the ASTM C78, a new concrete tensile strength test method is proposed. The test results show that the concrete tensile strength obtained by this proposed method is close to the value obtained from the direct tension test for concrete with compressive strengths from 25 to 55 MPa. It shows that this innovative test method, which is precise and easy to conduct, can be an effective alternative for tensile strength of concrete.

A Study on Improving the Adhesiveness between Granite and Asphalt by Nano-Scaled Calcium Carbonate

2013 ◽  
Vol 575-576 ◽  
pp. 54-57 ◽  
Author(s):  
Xiu Hong Hao ◽  
Yan Min Wang ◽  
Ai Qin Zhang
Keyword(s):  
Calcium Carbonate ◽  
Asphalt Concrete ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
Highway Engineering ◽  
Modified Asphalt ◽  
Marshall Test ◽  
The Matrix ◽  
Marshall Stability

Granite, due to the poor adhesiveness with asphalt, cannot be widely used as aggregate in asphalt pavement. In this study, nanoscaled calcium carbonate (CaCO3), was selected as modifier to modify asphalt. The adhesion of aggregate and asphalt was evaluated by Boiling test method and the Marshall Test and Immersion Marshall Test were conducted on asphalt concrete (AC-16) according to the Standard Test Methods of Bitumen and Bituminous Mixture for Highway Engineering (JTG E20-2011). The results showed that When the Doping content of CaCO3 (%) is 7%, the adhesion levels reached up to 5 grade and achieved the project requirements. The Immersion Marshall Stability (MS1) of AC-16 CaCO3 modified asphalt concrete can improve 27.6% than that the Matrix asphalt concrete.

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