Laboratory assessment of cold weather clothing

An overview of laboratory tests for cold weather clothing is provided starting from physical measurements on fabrics, and physical measurements on whole garments using thermal manikins. This is extended to human wear trials and climatic chamber experimentation. Insulation and vapour resistance are considered the most relevant parameters followed by wind and water proofness and moisture absorption properties. The use of test participants in wear trials is considered regarding the information provided by such tests. Tests for innovative fabrics (heated, variable insulation, phase change materials) are discussed. Finally testing of sleeping bags is considered

Structural integrity assessment of the welded joints of the constitution of 1812 bridge (Cádiz, Spain)

As required by the current Spanish regulations, an inspection and maintenance plan has been completed for the Constitution of 1812 Bridge over the Bay of Cádiz (Spain), which defines the work to be performed on the different elements of the bridge during its service life. The part of the plan related to the inspection of the steel structure has a section dedicated to the inspection of the defects that may be present in the welded joints of the steel deck, providing critical defect sizes above which the safety of the structure would be compromised. With this purpose, in the most stressed points of the deck, the structural details that are most susceptible to fatigue and fracture phenomena have been identified. Moreover, fatigue tests of these details have been performed to complete a structural integrity assessment that also comprises the determination of the material fracture toughness and the definition of the corresponding critical crack sizes. The tests were carried out on specimens obtained with the same steel grades as those used in the bridge and with the same welding procedures as those practiced in the structure. The results show that the fatigue test results are above the SN curves provided by the Eurocode 3, and also that numerous critical crack sizes would not be detected by the usual inspection techniques used in bridges (visual inspection), so that further research into how to manage this issue is recommended.The authors of this work would like to express their gratitude to the University of Cantabria for the financial support of the project “Aplicación de Técnicas de Integridad Estructural y Fiabilidad de Materiales en la Determinacion del Ciclo de Vida de Puentes Metalicos y Mixtos- Application of Structural Integrity and Materials Reliability Techniques to the Life-Cycle Assessment of Metallic and Steel-Concrete Composite Bridges” (03.DI09.649), programme of industrial doctorates, on the results of which this paper is based

Application of several pretreatment technologies to a wastewater effluent of a petrochemical industry finally treated with reverse osmosis

[EN] This work studies the adequacy of different reverse osmosis (RO) pretreatments applied to different petrochemical wastewater effluents. Three effluents from a caprolactam factory were analysed: ion-exchange resin washing effluent (RWE), batch reactor washing effluent and factory outlet effluent. Coagulation–flocculation, microfiltration (MF) and ultrafiltration (UF) were tested as RO pretreatments. Various inorganic coagulants (Aluminium Chloride, Iron (III) Chloride, Aluminium Sulphate and polyaluminium chloride), commercial coagulants (Nophos and ACO) and commercial flocculants (polyacrylamide, CH-30 and active polyfloc) were tested at different dosages and stirring speeds. The highest removal of suspended solids (SS) and the lowest turbidity were obtained for the ion-exchange RWE. Two combinations of coagulants and flocculants were chosen as the most suitable conditions for the coagulation–flocculation process. The ion-exchange RWE was further treated with a combination of MF followed by UF. SS were completely removed and turbidity decreased to 0.136 NTU. The silt density index at 15 min was reduced to 6.41.The authors of this work wish to gratefully acknowledge the financial support from the Generalitat Valenciana through the programme “Ayudas para la realizacio´n de proyectos I+D para grupos de investigacio´n emergentes GV/2013”.Vincent Vela, MC.; Alvarez Blanco, S.; Lora García, J.; Carbonell Alcaina, C.; Sáez Muñoz, M. (2014). Application of several pretreatment technologies to a wastewater effluent of a petrochemical industry finally treated with reverse osmosis. Desalination and Water Treatment. 1-9. doi:10.1080/19443994.2014.939866S19Benito-Alcázar, C., Vincent-Vela, M. C., Gozálvez-Zafrilla, J. M., & Lora-García, J. (2010). Study of different pretreatments for reverse osmosis reclamation of a petrochemical secondary effluent. Journal of Hazardous Materials, 178(1-3), 883-889. doi:10.1016/j.jhazmat.2010.02.020Madaeni, S. S., & Eslamifard, M. R. (2010). Recycle unit wastewater treatment in petrochemical complex using reverse osmosis process. Journal of Hazardous Materials, 174(1-3), 404-409. doi:10.1016/j.jhazmat.2009.09.067Kim, H.-C., & Dempsey, B. A. (2008). Effects of wastewater effluent organic materials on fouling in ultrafiltration. Water Research, 42(13), 3379-3384. doi:10.1016/j.watres.2008.04.021Karabacakoğlu, B., Tezakıl, F., & Güvenç, A. (2014). Removal of hardness by electrodialysis using homogeneous and heterogeneous ion exchange membranes. Desalination and Water Treatment, 54(1), 8-14. doi:10.1080/19443994.2014.880159Gare, S. (2002). RO systems: the importance of pre-treatment. Filtration & Separation, 39(1), 22-27. doi:10.1016/s0015-1882(02)80047-7Garg, A., Mishra, I. M., & Chand, S. (2010). Effectiveness of coagulation and acid precipitation processes for the pre-treatment of diluted black liquor. Journal of Hazardous Materials, 180(1-3), 158-164. doi:10.1016/j.jhazmat.2010.04.008Verma, S., Prasad, B., & Mishra, I. M. (2010). Pretreatment of petrochemical wastewater by coagulation and flocculation and the sludge characteristics. Journal of Hazardous Materials, 178(1-3), 1055-1064. doi:10.1016/j.jhazmat.2010.02.047Garrote, J. (1995). Treatment of tannery effluents by a two step coagulation/flocculation process. Water Research, 29(11), 2605-2608. doi:10.1016/0043-1354(94)00312-uSanto, C. E., Vilar, V. J. P., Botelho, C. M. S., Bhatnagar, A., Kumar, E., & Boaventura, R. A. R. (2012). Optimization of coagulation–flocculation and flotation parameters for the treatment of a petroleum refinery effluent from a Portuguese plant. Chemical Engineering Journal, 183, 117-123. doi:10.1016/j.cej.2011.12.041Wang, J.-P., Chen, Y.-Z., Wang, Y., Yuan, S.-J., & Yu, H.-Q. (2011). Optimization of the coagulation-flocculation process for pulp mill wastewater treatment using a combination of uniform design and response surface methodology. Water Research, 45(17), 5633-5640. doi:10.1016/j.watres.2011.08.023Rossini, M., Garrido, J. G., & Galluzzo, M. (1999). Optimization of the coagulation–flocculation treatment: influence of rapid mix parameters. Water Research, 33(8), 1817-1826. doi:10.1016/s0043-1354(98)00367-4Guida, M., Mattei, M., Della Rocca, C., Melluso, G., & Meriç, S. (2007). Optimization of alum-coagulation/flocculation for COD and TSS removal from five municipal wastewater. Desalination, 211(1-3), 113-127. doi:10.1016/j.desal.2006.02.086HABERKAMP, J., RUHL, A., ERNST, M., & JEKEL, M. (2007). Impact of coagulation and adsorption on DOC fractions of secondary effluent and resulting fouling behaviour in ultrafiltration. Water Research, 41(17), 3794-3802. doi:10.1016/j.watres.2007.05.029Petrov, S., & Stoichev, P. (2002). Reagent ultrafiltration purification of water contaminated with reactive dyes. Filtration & Separation, 39(8), 35-34. doi:10.1016/s0015-1882(02)80229-4Shon, H. K., Vigneswaran, S., Ngo, H. H., & Ben Aim, R. (2005). Is semi-flocculation effective as pretreatment to ultrafiltration in wastewater treatment? Water Research, 39(1), 147-153. doi:10.1016/j.watres.2004.09.003Hatt, J. W., Germain, E., & Judd, S. J. (2011). Precoagulation-microfiltration for wastewater reuse. Water Research, 45(19), 6471-6478. doi:10.1016/j.watres.2011.09.039Dryden Aqua Ltd, Edinburgh, 2013. Available from: www.DrydenAqua.com (April 6, 2013).Sincero, A. P., & Sincero, G. A. (2002). Physical-Chemical Treatment of Water and Wastewater. doi:10.1201/978142003190

Use of laser interferometry for measuring concrete substrate roughness in patch repairs

The overall success and long-term durability of a patch repair is significantly influenced by the bond developed at the interface between the concrete substrate and the repair material. In turn, the bond strength is influenced by the topography (roughness) of the substrate surface after removal of the defective concrete. However, different removal methods of defective concrete produce substrate surfaces with different topographies. Hence, the ability to measure and characterise the topography of substrate surfaces is of great importance for evaluating the effectiveness of different removal methods. In this paper, the effect of two removal methods: electric chipping hammers and Remote Robotic Hydro-erosion (RRH) on the surface roughness is investigated through the use of a prototype non-contact (optical) laser interferometry measuring device. Laboratory results show that the above equipment can be used to characterise substrate roughness and confirm the ability of RRH to create rougher surfaces as opposed to chipping hammers

Elevated temperature material properties of stainless steel reinforcing bar

Corrosion of carbon steel reinforcing bar can lead to deterioration of concrete structures, especially in regions where road salt is heavily used or in areas close to sea water. Although stainless steel reinforcing bar costs more than carbon steel, its selective use for high risk elements is cost-effective when the whole life costs of the structure are taken into account. Considerations for specifying stainless steel reinforcing bars and a review of applications are presented herein. Attention is then given to the elevated temperature properties of stainless steel reinforcing bars, which are needed for structural fire design, but have been unexplored to date. A programme of isothermal and anisothermal tensile tests on four types of stainless steel reinforcing bar is described: 1.4307 (304L), 1.4311 (304LN), 1.4162 (LDX 2101®) and 1.4362 (2304). Bars of diameter 12 mm and 16 mm were studied, plain round and ribbed. Reduction factors were calculated for the key strength, stiffness and ductility properties and compared to equivalent factors for stainless steel plate and strip, as well as those for carbon steel reinforcement. The test results demonstrate that the reduction factors for 0.2% proof strength, strength at 2% strain and ultimate strength derived for stainless steel plate and strip can also be applied to stainless steel reinforcing bar. Revised reduction factors for ultimate strain and fracture strain at elevated temperatures have been proposed. The ability of two-stage Ramberg-Osgood expressions to capture accurately the stress-strain response of stainless steel reinforcement at both room temperature and elevated temperatures is also demonstrated

Standardisation of magnetic nanoparticles in liquid suspension

Suspensions of magnetic nanoparticles offer diverse opportunities for technology innovation, spanning a large number of industry sectors from imaging and actuation based applications in biomedicine and biotechnology, through large-scale environmental remediation uses such as water purification, to engineering-based applications such as position-controlled lubricants and soaps. Continuous advances in their manufacture have produced an ever-growing range of products, each with their own unique properties. At the same time, the characterisation of magnetic nanoparticles is often complex, and expert knowledge is needed to correctly interpret the measurement data. In many cases, the stringent requirements of the end-user technologies dictate that magnetic nanoparticle products should be clearly defined, well characterised, consistent and safe; or to put it another way—standardised. The aims of this document are to outline the concepts and terminology necessary for discussion of magnetic nanoparticles, to examine the current state-of-the-art in characterisation methods necessary for the most prominent applications of magnetic nanoparticle suspensions, to suggest a possible structure for the future development of standardisation within the field, and to identify areas and topics which deserve to be the focus of future work items. We discuss potential roadmaps for the future standardisation of this developing industry, and the likely challenges to be encountered along the way

Estimating the Background Ventilation Rates in New-Build UK Dwellings – is n50/20 appropriate?

In the UK, a rule of thumb applied to air permeability is commonly employed when estimating background ventilation rates from pressurisation test data. However, this may lead to significant errors in estimating the infiltration rates in UK new-build dwellings, resulting in poor estimation of the dwellings in-use energy and CO2 emissions, and the adoption of ventilation strategies leading to either unacceptable indoor air quality or unnecessary energy consumption. In this paper, a preliminary investigation into the applicability of the rule of thumb is undertaken. Background ventilation rates in four new-build dwellings in the UK are determined using the tracer-gas decay method and also the pressurisation (blower-door) method coupled with both the conventional n50/20 and (in the UK) q50/20 rule of thumb, and Sherman’s modified rule of thumb, which takes into account other building-related factors. The conventional method over-estimated the air-change rate in two of the dwellings and under-estimated it in the other two dwellings. The modified rule of thumb produced comparable results for two of the dwellings, but significantly underestimated the air-change rate in the other two dwellings. These results suggest that more work needs to be done to devise appropriate climate and building-related correction factors for the UK

Indentation Hardness Measurements at Macro-, Micro-, and Nanoscale: A Critical Overview

The Brinell, Vickers, Meyer, Rockwell, Shore, IHRD, Knoop, Buchholz, and nanoindentation methods used to measure the indentation hardness of materials at different scales are compared, and main issues and misconceptions in the understanding of these methods are comprehensively reviewed and discussed. Basic equations and parameters employed to calculate hardness are clearly explained, and the different international standards for each method are summarized. The limits for each scale are explored, and the different forms to calculate hardness in each method are compared and established. The influence of elasticity and plasticity of the material in each measurement method is reviewed, and the impact of the surface deformation around the indenter on hardness values is examined. The difficulties for practical conversions of hardness values measured by different methods are explained. Finally, main issues in the hardness interpretation at different scales are carefully discussed, like the influence of grain size in polycrystalline materials, indentation size effects at micro-and nanoscale, and the effect of the substrate when calculating thin films hardness. The paper improves the understanding of what hardness means and what hardness measurements imply at different scales.Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University ((Faculty Grant SFO Mat LiU) [2009 00971]</p

Review Paper on Road Vehicle Vibration Simulation for Packaging Testing Purposes

Inefficient packaging constitutes a global problem that costs hundreds of billions of dollars, not to mention the additional environmental impacts. An insufficient level of packaging increases the occurrence of product damage, while an excessive level increases the packages' weight and volume, thereby increasing distribution cost. This problem is well known, and for many years, engineers have tried to optimize packaging to protect products from transport hazards for minimum cost. Road vehicle shocks and vibrations, which is one of the primary causes of damage, need to be accurately simulated to achieve optimized product protection. Over the past 50 years, road vehicle vibration physical simulation has progressed significantly from simple mechanical machines to sophisticated computer-driven shaking tables. There now exists a broad variety of different methods used for transport simulation. Each of them addresses different particularities of the road vehicle vibration. Because of the nature of the road and vehicles, different sources and processes are present in the vibration affecting freight. Those processes can be simplified as the vibration generated by the general road surface unevenness, road surface aberrations (cracks, bumps, potholes, etc.) and the vehicle drivetrain system (wheels, drivetrain, engine, etc.). A review of the transport vibration simulation methods is required to identify and critically evaluate the recent developments. This review begins with an overview of the standardized methods followed by the more advanced developments that focus on the different random processes of vehicle vibration by simulating non-Gaussian, non-stationary, transient and harmonic signals. As no ideal method exists yet, the review presented in this paper is a guide for further research and development on the topic

Fire design method for concrete filled tubular columns based on equivalent concrete core cross-section

In this work, a method for a realistic cross-sectional temperature prediction and a simplified fire design method for circular concrete filled tubular columns under axial load are presented. The generalized lack of simple proposals for computing the cross-sectional temperature field of CFT columns when their fire resistance is evaluated is evident. Even Eurocode 4 Part 1-2, which provides one of the most used fire design methods for composite columns, does not give any indications to the designers for computing the cross-sectional temperatures. Given the clear necessity of having an available method for that purpose, in this paper a set of equations for computing the temperature distribution of circular CFT columns filled with normal strength concrete is provided. First, a finite differences thermal model is presented and satisfactorily validated against experimental results for any type of concrete infill. This model consideres the gap at steel-concrete interface, the moisture content in concrete and the temperature dependent properties of both materials. Using this model, a thermal parametric analysis is executed and from the corresponding statistical analysis of the data generated, the practical expressions are derived. The second part of the paper deals with the development of a fire design method for axially loaded CFT columns based on the general rules stablished in EN 1994-1-1 and employing the concept of room temperature equivalent concrete core cross-section. In order to propose simple equations, a multiple nonlinear regression analysis is made with the numerical results generated through a thermo-mechanical parametric analysis. Once more, predicted results are compared to experimental values giving a reasonable accuracy and slightly safe results.The authors would like to express their sincere gratitude to the Spanish Ministry of Economy and Competitivity for the help provided through the project BIA2012-33144, and to the European Community for the FEDER funds.Ibáñez Usach, C.; Aguado, JV.; Romero, ML.; Espinós Capilla, A.; Hospitaler Pérez, A. (2015). Fire design method for concrete filled tubular columns based on equivalent concrete core cross-section. Fire Safety Journal. 78:10-23. https://doi.org/10.1016/j.firesaf.2015.07.009S10237