Name: determination of the mechanical properties of flexible connectors for use in insulated concrete wall panels
Uploaded: 2022-10-19T15:00:00
Description: Watch this Scientific Journal Video about Determination of the Mechanical Properties of Flexible Connectors for Use in Insulated Concrete Wall Panels at JoVE.com

The work described above was not directly financed by a single organization or over the course of a single grant, but the information was gathered over years of industry-sponsored research. To that end, the authors thank their sponsors from over the last decade and are grateful to work in a rapidly evolving industry.

1. Fabricating the testing specimen
<ol>
	<li>Select the discrete or continuous shear connector to test and adhere to the dimensions of the specimen indicated in Figure 4. Modify the dimensions to the test edge distance clearances if needed by changing the edge distance for the connector. 
	NOTE: Generally, adhering to the manufacturer&#39;s guidelines is important, though this test may be used to develop these guidelines. The concrete and insulation wythe dimensions ...

<ol>
	<li>Collins, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precast+concrete+sandwich+panels+for+tilt-up+construction.">Precast concrete sandwich panels for tilt-up construction.</a> Journal of the American Concrete Institute. 50 (2), 149-164 (1954).</li><li>Luebke, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Out-of-plane behavior of concrete insulated wall panels with 2-inch, 8-inch, and 10-inch insulation. , (2021).</li><li>Einea, A., Salmon, D. C., Tadros, M. K., Culp, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+structurally+and+thermally+efficient+precast+sandwich+panel+system.">A new structurally and thermally efficient precast sandwich panel system.</a> PCI journal. 39 (4), 90-101 (1994).</li><li>Frankl, B., Lucier, G., Rizkalla, S., Blaszak, G., Harmon, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+behavior+of+insulated+prestressed+concrete+sandwich+panels+reinforced+with+FRP+grid.">Structural behavior of insulated prestressed concrete sandwich panels reinforced with FRP grid.</a> Proceedings of the Fourth International Conference on FRP Composites in Civil Engineering (CICE2008). 2224, (2008).</li><li>Naito, C., Hoemann, J., Beacraft, M., Bewick, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Performance+and+characterization+of+shear+ties+for+use+in+insulated+precast+concrete+sandwich+wall+panels.">Performance and characterization of shear ties for use in insulated precast concrete sandwich wall panels.</a> Journal of Structural Engineering. 138 (1), 52-61 (2012).</li><li>Tomlinson, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Behaviour of partially composite precast concrete sandwich panels under flexural and axial loads. , (2015).</li><li>. AC320 - Fiber-reinforced Polymer Composite or Unreinforced Polymer Connectors Anchored in Concrete Available from: <a target="_blank" href="https://shop.iccsafe.org/es-acceptance-criteria/ac320-fiber-reinforced-polymer-composite-or-unreinforced-polymer-connectors-anchored-in-concrete-approved-oct-2015-editorially-revised-sept-2017-pdf-download.html">https://shop.iccsafe.org/es-acceptance-criteria/ac320-fiber-reinforced-polymer-composite-or-unreinforced-polymer-connectors-anchored-in-concrete-approved-oct-2015-editorially-revised-sept-2017-pdf-download.html</a> (2015)</li><li>. Developing a General Methodology for Evaluating Composite Action in Insulated Wall Panels. Report to PCI. Precast/Prestressed Concrete Institute Available from: <a target="_blank" href="https://digitalcommons.usu.edu/cee_facpub/3531">https://digitalcommons.usu.edu/cee_facpub/3531</a> (2017)</li><li>Gombeda, M. J., Naito, C. J., Quiel, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+performance+of+a+ductile+shear+tie+for+precast+concrete+insulated+wall+panels.">Development and performance of a ductile shear tie for precast concrete insulated wall panels.</a> Journal of Building Engineering. 28, 101084 (2020).</li><li>Kinnane, O., West, R., Grimes, M., Grimes, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shear+capacity+of+insulated+precast+concrete+fa&#231;ade+panels.">Shear capacity of insulated precast concrete fa&#231;ade panels.</a> CERI 2014 - Civil Engineering Research in Ireland. , (2014).</li><li>Jiang, H., Guo, Z., Liu, J., Liu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+shear+behavior+of+precast+concrete+sandwich+panels+with+W-shaped+SGFRP+shear+connectors.">The shear behavior of precast concrete sandwich panels with W-shaped SGFRP shear connectors.</a> KSCE Journal of Civil Engineering. 22 (10), 3961-3971 (2018).</li><li>ASTM International. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+test+methods+for+strength+of+anchors+in+concrete+elements.">Standard test methods for strength of anchors in concrete elements.</a> ASTM. , (2022).</li><li>Syndergaard, P., Tawadrous, R., Al-Rubaye, S., Maguire, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparing+testing+methods+of+partially+composite+sandwich+wall+panel+glass+fiber-reinforced+polymer+connectors.">Comparing testing methods of partially composite sandwich wall panel glass fiber-reinforced polymer connectors.</a> Journal of Composites for Construction. 26 (1), (2022).</li><li>Woltman, G., Tomlinson, D., Fam, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+of+various+GFRP+shear+connectors+for+insulated+precast+concrete+sandwich+wall+panels.">Investigation of various GFRP shear connectors for insulated precast concrete sandwich wall panels.</a> Journal of Composites for Construction. 17 (5), 711-721 (2013).</li><li>Olsen, J., Maguire, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pushoff+shear+testing+of+composite+sandwich+panel+connectors.">Pushoff shear testing of composite sandwich panel connectors.</a> 2016 PCI Convention and National Bridge Conference. , (2016).</li><li>Gombeda, M. J., Naito, C. J., Quiel, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flexural+performance+of+precast+concrete+insulated+wall+panels+with+various+configurations+of+ductile+shear+ties.">Flexural performance of precast concrete insulated wall panels with various configurations of ductile shear ties.</a> Journal of Building Engineering. 33, 101574 (2021).</li><li>Bai, F., Davidson, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Composite+beam+theory+for+pretensioned+concrete+structures+with+solutions+to+transfer+length+and+immediate+prestress+losses.">Composite beam theory for pretensioned concrete structures with solutions to transfer length and immediate prestress losses.</a> Engineering Structures. 126, 739-758 (2016).</li><li>Cox, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lumped+GFRP+star+connector+system+for+partial+composite+action+in+insulated+precast+concrete+sandwich+panels.">Lumped GFRP star connector system for partial composite action in insulated precast concrete sandwich panels.</a> Composite Structures. 229, 111465 (2019).</li><li>Pozo, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> On thermal bowing of concrete sandwich wall panels with flexible shear connectors. , (2018).</li><li>ASTM International. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+practice+for+making+and+curing+concrete+test+specimens+in+the+field.">Standard practice for making and curing concrete test specimens in the field.</a> ASTM International. , (2019).</li><li>ASTM International. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+test+method+for+compressive+strength+of+cylindrical+concrete+specimens.">Standard test method for compressive strength of cylindrical concrete specimens.</a> ASTM International. , (2018).</li><li>Pozo-Lora, F., Maguire, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+bowing+of+concrete+sandwich+panels+with+flexible+shear+connectors.">Thermal bowing of concrete sandwich panels with flexible shear connectors.</a> Journal of Building Engineering. 29, 101124 (2020).</li><li>Al-Rubaye, S., Sorensen, T., Thomas, R. J., Maguire, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generalized+beam-spring+model+for+predicting+elastic+behavior+of+partially+composite+concrete+sandwich+wall+panels.">Generalized beam-spring model for predicting elastic behavior of partially composite concrete sandwich wall panels.</a> Engineering Structures. 198, 109533 (2019).</li><li>Losch, E. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=State+of+the+art+of+precast/prestressed+concrete+sandwich+wall+panels.">State of the art of precast/prestressed concrete sandwich wall panels.</a> PCI Journal. 56 (2), 131-176 (2011).</li><li>Al-Rubaye, S., Sorensen, T., Maguire, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Iterative+and+simplified+sandwich+beam+theory+for+partially+composite+concrete+sandwich+wall+panels.">Iterative and simplified sandwich beam theory for partially composite concrete sandwich wall panels.</a> Journal of Structural Engineering. 147 (10), 4021143 (2021).</li><li>Holmberg, A., Plem, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behaviour+of+Load-bearing+Sandwich-type+Structures.">Behaviour of Load-bearing Sandwich-type Structures.</a> The National Swedish Institute for Building Research. , (1965).</li><li>Naito, C. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precast/prestressed+concrete+experiments+performance+on+non-load+bearing+sandwich+wall+panels.">Precast/prestressed concrete experiments performance on non-load bearing sandwich wall panels.</a> Air Force Research Laboratory. Materials and Manufacturing Directorate. , (2011).</li><li>Al-Rubaye, S., Sorensen, T., Olsen, J., Maguire, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluating+elastic+behavior+for+partially+composite+precast+concrete+sandwich+wall+panels.">Evaluating elastic behavior for partially composite precast concrete sandwich wall panels.</a> PCI Journal. 63 (5), 71-88 (2018).</li><li>ASTM International. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standard+practice+for+conducting+ruggedness+tests.">Standard practice for conducting ruggedness tests.</a> ASTM International. , 1169-1121 (2021).</li></ol>

Many researchers have used some variation of this type of test for ICSWP, but this is the first instance of outlining all the individual steps. The literature does not address the critical steps in testing, including sensor types and specimen handling. This method describes a manner of testing that mimics more closely the behavior of the connectors when a panel is loaded in flexure as opposed to the single-shear test. There are several variables for this work that are yet to be studied. Specifically, information related ...

Insulated concrete sandwich wall panels (ICSWPs) comprise a layer of insulation placed in between two concrete layers, often called wythes, which synergically provide a thermally and structurally efficient component for building envelopes or load-bearing panels1 (Figure 1). To adapt to the rapidly changing construction industry and new building code regulations on thermal efficiency, precasters are fabricating ICSWPs with thinner concrete layers and thicker insulation layers with higher thermal resistance; additionally, designers are using more refined methods to account for the partially composite interaction of the concrete wythes to reduce the overall building costs while increasing the thermal and structural performance2. While it is known that structural efficiency largely depends on the structural connection between the concrete layers and that multiple proprietary shear connectors are available on the market, no standardized testing protocol exists in the literature to examine the mechanical properties of those connectors. The available connectors vary widely in their geometry, materials, and manufacturing, so it is difficult to obtain a unified analytical approach to determine their mechanical properties. For this reason, many researchers have used their own customized setups in the lab that try to mimic the fundamental behavior of the connectors at the service and strength limit states3,4,5,6,7,8,9,10. However, only two of them are part of a testing evaluation scheme5,8, despite them not being useful for all ranges of connectors due to their wide variation in shape, stiffness, and material composition.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/64292/64292fig01.jpg" /> 
Figure 1: Typical composition of a sandwich wall panel specimen. <a href="https://www.jove.com/files/ftp_upload/64292/64292fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
A common method for testing these connectors is what is often termed single shear with either one row or two rows of connectors, as described previously3,11,12, which is often based on ASTM E488, a concrete anchor testing standard13. ASTM E488 does not require, but strongly implies through drawings of the suggested test setups, that a single anchor protruding from a fixed base of concrete will be tested. Once the specimens are tested, a set of load versus displacement curves is plotted, and the average values of the ultimate elastic load (Fu) and the elastic stiffness (K0.5Fu) are obtained from such curves. One of the main advantages of using this approach is that it produces low-variability results and does not necessitate large lab spaces or many sensors14. A different approach consists of loading a wythe connector in double shear to determine the mechanical properties for use in the design of those panels6,7,14,15,16. The resulting data are processed in the same fashion, and the average values of the ultimate elastic load (Fu) and the elastic stiffness (K0.5Fu) are obtained from testing. Although this testing approach involves using more material and needs more sensors, it is anecdotally easier to apply the loading and boundary conditions in a laboratory.
The two styles of testing do not seem dramatically different but produce different results largely based on their ability to mimic the connector behavior in a full-scale panel. The single-shear, single-row test setup produces a pinching action, as displayed in Figure 2B,C, and an additional overturning moment, as described previously14,17, which would not be present in a full-scale panel. The double shear does a better job of mimicking this full-scale behavior-it models the pure shear translation of the outer wythes relative to the central wythe. As a result, the double-shear values employed in analytical methods have been shown to produce results that are closer to those obtained in large-scale testing of representative insulated wall panels14. Figure 3 shows the schematic test setup for the single- and double-shear testing of a connector.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/64292/64292fig02.jpg" /> 
Figure 2: Examples of different connector testing configurations employed in the literature. Single connector specimens have been shown to cause loading that does not represent the parallel translation of wythes seen in full-scale panels. (A)&#160;Double shear with two connectors; (B) Double shear with one connector; (C) Single shear with one connector. <a href="https://www.jove.com/files/ftp_upload/64292/64292fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
A common denominator of all these studies&#39; conclusions is that both the testing methodologies are appropriate for determining the mechanical properties of flexible connectors, but the double-shear testing scheme results resemble more closely the behavior of the connector in a real panel under flexure. In other words, when the user employs such testing results in an analytical model, they closely match the results of large-scale tests where the connectors are used. It is important to mention that the results of such testing are appropriate for models that rely on the mechanical properties as input design parameters directly, such as empirically derived methods, closed-form solutions of the sandwich beam theory, and finite element models with 2-D and 3-D springs7,18,19,20.
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/64292/64292fig03.jpg" /> 
Figure 3: Schematic view of the testing protocols in the literature. A ram is used to translate the wythes of the specimens relative to each other.&#160;(A) Single-shear and (B) double-shear testing protocols. <a href="https://www.jove.com/files/ftp_upload/64292/64292fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In this work, an experimental protocol for obtaining the values of the backbone curve and the mechanical properties of insulated wall panel wythe connectors, namely Fu and K0.5Fu, is presented. The method is based on testing connectors using a double-shear test approach with some modifications to eliminate sources of variability and produce more reliable results. All the samples are constructed in a temperature-controlled environment, where they are tested when the concrete reaches the target compressive strength. The main advantage of this testing protocol is that it can be easily followed, can be replicated by different technicians, and closely describes the real behavior of the wythe connector in a real, insulated concrete wall panel under flexure or flexure and axial force combined, as has been shown in the literature.
The application of the suggested wythe connector testing protocol for determining the mechanical properties and material behavior will enhance the accuracy of testing results for the insulated concrete wall panel industry and decrease the barriers for entrepreneurs interested in creating innovative new connectors. The future large increase in insulated panel construction in both the tilt-up and precast concrete industries will require better use of materials and more unified methods to obtain engineering properties of the panels.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Battery-powered Drill</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Concrete Screws</td>
			<td></td>
			<td></td>
			<td>50 mm long commercial concrete scews.</td>
		</tr>
		<tr>
			<td>Data Logger</td>
			<td></td>
			<td></td>
			<td>Capable of sampling at a frequency of at least 10 Hz.</td>
		</tr>
		<tr>
			<td>Double Shear Test Specimen</td>
			<td></td>
			<td></td>
			<td>Fabricated according to the dimmensions in the testing protocol.</td>
		</tr>
		<tr>
			<td>Four Linear Variable Displacement Transformer</td>
			<td></td>
			<td></td>
			<td>With at least 25 mm range for Fiber-reinforced Polymer (FRP) connectors and 50 mm for ductile steel connectors.</td>
		</tr>
		<tr>
			<td>Hydraulic Actuator</td>
			<td></td>
			<td></td>
			<td>With at least 50-Ton capacity.</td>
		</tr>
		<tr>
			<td>Lifting anchors rated at 1 Ton</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Load Cell</td>
			<td></td>
			<td></td>
			<td>With at least 50-Ton capacity.</td>
		</tr>
		<tr>
			<td>Load Frame</td>
			<td></td>
			<td></td>
			<td>Capable of resisting the forces generated by the testing specimen.</td>
		</tr>
		<tr>
			<td>Polytetrafluoroethylene (PTFE) Pads</td>
			<td></td>
			<td></td>
			<td>3 mm x 100 mm x 600 mm&#160;</td>
		</tr>
		<tr>
			<td>Ratchet Strap</td>
			<td></td>
			<td></td>
			<td>At least 50 mm wide.</td>
		</tr>
		<tr>
			<td>Steel angle</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Steel Plate</td>
			<td></td>
			<td></td>
			<td>Two 20 mm x 150 mm x 150 mm steel plates.</td>
		</tr>
		<tr>
			<td>Steel Washers</td>
			<td></td>
			<td></td>
			<td>Capable of producing a separation of at least 5 mm between the steel angle and the specimen.</td>
		</tr>
	</tbody>
</table>

determination of the mechanical properties of flexible connectors for use in insulated concrete wall panels

This document contains recommendations for performing a non-standard, double-shear test suitable for both continuous and discrete insulated concrete sandwich wall panels (ICSWPs). Such a standardized test does not exist, but several iterations of this and similar tests have been performed in the literature to varying degrees of success. Further, the tests in the literature are rarely-if ever-described in detail or discussed at length with respect to the testing, data analysis, or safety procedures. A test specimen configuration is recommended herein, and variations are discussed. Important mechanical properties are identified from the load versus displacement data, and their extraction is detailed. The use of test data for design, such as for determining the stiffness of the connectors, is briefly demonstrated to show how ICSWP deflection and cracking behavior may be calculated. The strength behavior of panels may be determined using the full load versus displacement curve or only the maximum connector strength. Shortcomings and unknowns are acknowledged, and significant future work is delineated.

Figure 8 and Figure 9A show a typical load per connector versus the average displacement curve resulting from a double-shear test of a fiber-reinforced polymer (FRP) connector in the laboratory. As the figures depict, the load increases steadily up to the maximum point and then drops dramatically, which is typically observed in most testing involving polymers. However, as Figure 9B suggests, the curve flattens after the maximum load...

Watch this Scientific Journal Video about Determination of the Mechanical Properties of Flexible Connectors for Use in Insulated Concrete Wall Panels at JoVE.com

Determination of the Mechanical Properties of Flexible Connectors for Use in Insulated Concrete Wall Panels

We propose a testing protocol that can be combined with widely available analytical methods to assess the mechanical properties of shear connectors for use in the design of insulated concrete wall panels to predict full-scale insulated panel behavior.

This document contains recommendations for performing a non-standard, double-shear test suitable for both continuous and discrete insulated concrete ...

Research

Education

JoVE Core

JoVE Journal

Civil Engineering

Engineering

Unit 1

Masonry

SCIENTISTS IN ACTION

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

A Cost-effective and Reliable Method to Predict Mechanical Stress in Single-use and Standard Pumps

Pumps are mainly used when transferring sterile culture broths in biopharmaceutical and biotechnological production processes. However, during the pumping ...

Design and Use of a Full Flow Sampling System (FFS) for the Quantification of Methane Emissions

Design and Use of a Full Flow Sampling System FFS for the Quantification of Methane Emissions

The use of natural gas continues to grow with increased discovery and production of unconventional shale resources. At the same time, the natural gas ...

A Novel Biaxial Testing Apparatus for the Determination of Forming Limit under Hot Stamping Conditions

The hot stamping and cold die quenching process is increasingly used to form complex shaped structural components of sheet metals. Conventional ...

Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a ...

Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures

The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these ...

Magnet Assisted Composite Manufacturing: A Flexible New Technique for Achieving High Consolidation Pressure in Vacuum Bag/Lay-Up Processes

This work demonstrates a protocol to improve the quality of composite laminates fabricated by wet lay-up vacuum bag processes using the recently developed ...

Using Flexible Gold-Titanium Reaction Cells to Simulate Pressure-Dependent Microbial Activity in the Context of Subsurface Biomining

Laboratory studies investigating subsurface microbial processes, such as metal leaching in deep ore deposits (biomining), share common and challenging ...

Determining the Mechanical Strength of Ultra-Fine-Grained Metals

The mechanical strengthening of metals is the long-standing challenge and popular topic of materials science in industries and academia. The size ...

Assembly and Characterization of an External Driver for the Generation of Sub-Kilohertz Oscillatory Flow in Microchannels

Microfluidic technology has become a standard tool in chemical and biological laboratories for both analysis and synthesis. The injection of liquid ...