• 3D FEA modelling of laminated composites in bending and their failure mechanisms

      Meng, Maozhou; Le, Huirong; Rizvi, Jahir; Grove, Stephen; University of Plymouth (2014-10-02)
    • 3D multilayered Bi4O5Br2 nanoshells displaying excellent visible light photocatalytic degradation behaviour for resorcinol.

      Hu, Hanmei; Xu, Juanjuan; Deng, Chonghai; Wang, Man; Zhou, Xiaoyu; Le, Huirong; Anhui Jianzhu University; Hefei University; University of Derby (The Institution of Engineering and Technology, 2018-04-26)
      High-ordered three-dimensional multilayered Bi4O5Br2 nanoshells have been fabricated successfully via a green ultrasound-assisted anion exchange reaction followed by a calcination treatment approach. The products are characterised by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, UV–vis diffuse reflectance spectrum and N2 adsorption/desorption isotherms. The results reveal that ternary Bi4O5Br2 nanoshells possess a pure monoclinic phase with the average thickness of ca. 12 nm, and the walls are of 10–12 layers constructed by nanograins with 10 nm in size. The specific surface is measured to be 36.18 m2 g-1 and the band gap energy E g value is calculated to be 2.52 eV. The possible formation process for Bi4O5Br2 nanoshells is simply proposed. According to the photocatalytic degradation for resorcinol under visible light irradiation, the as-prepared Bi4O5Br2 nanoshells exhibit excellent photocatalytic performance, which is not only far beyond the degradation rate of BiOBr precursor nanosheets but also superior to that of other reported Bi4O5Br2 architectures, suggesting a practical application for the treatment of organic pollutants.
    • The Accuracy of Thermal Comfort Zone, ASHRAE Standard 55-2013. CIBSE Technical Symposium 2016

      Shahzad, Sally; Brennan, John; Theodossopoulos, Dimitris; Hughes, Ben; Calautit, John Kaiser; University of Derby; University of Edinburgh; University of Sheffield (CIBSE, 2016)
      This study examined the accuracy of thermal comfort zone (ASHRAE Standard 55-2013) in four offices in Norway and the UK. Thermal environment of the workplace is arranged according to this standard, which predicts to satisfy over 80% of occupants. However, users report dissatisfaction regarding the thermal environment. This study investigated the application of the most widely used thermal comfort standard in practice. Field studies of thermal comfort with recordings of the thermal environment, survey questionnaires and interviews were applied. The results did not agree with the PMV and adaptive prediction models by the ASHRAE Standard 55-2013. The follow up interviews revealed the significance of individual differences in perceiving the thermal environment and the impact of the availability of thermal control on user satisfaction.
    • Adapting Buildings to meet the Energy Challenge

      Calautit, John Kaiser; Hughes, Ben; Shahzad, Sally; University of Sheffield; University of Derby (2014)
    • Additive manufacturing for maritime spare parts supply: An overview.

      Ye, Jilin; Southampton Solent University (Shanghai University of Traditional Chinese Medicine Press, 2016)
      Additive Manufacturing (AM), also called 3D Printing (3DP) is not a new technology. The technology was invented over 30 years ago. Originally thought of as simply an application for rapid prototyping, it has developed significantly and is now a viable option for many applications including aerospace, automotive, healthcare, construction and consumer products. This paper offers a brief introduction to the history of AM/3DP and an overview of the current state of the art in AM/3DP technologies focusing on their fundamental processes, typical materials, significant benefits, key applications and critical challenges to implementation. Finally a description of the potential benefits to the maritime industry that can be gained by implementation of AM/3DP technologies is presented. The most immediate is the possibility of more efficient logistics, for example the maritime spare parts supply.
    • Advanced nanocomposite coating for offshore threaded connections

      Sieh, Raymond; Le, Huirong; Cree, Alistair; University of Plymouth (9th Nanosmat International Conference, 2015-09)
    • Advanced personal comfort system (APCS) for the workplace: A review and case study.

      Shahzad, Sally; Calautit, John Kaiser; Calautit, Katrina; Hughes, Ben; Aquino, Angelo I.; University of Derby; University of Nottingham; University of Sheffield (Elsevier, 2018-02-13)
      The aim of this research is to investigate the application and performance of an advanced personal comfort system, a thermal chair, using Computational Fluid Dynamics (CFD), Building Energy Simulation (BES) and field test analysis. The thermal chair permits individual control over their immediate thermal environment without affecting the thermal environment and comfort of other occupants. A comprehensive review on the existing research on the design and performance of various personalised thermal control systems was carried out. A prototype of a thermal chair was designed for the study and tested in an open plan office during the heating season in Leeds, UK. 45 individuals used the chair in their everyday context of work and a survey questionnaire was applied to record their views of the thermal environment before and after using the chair. The performance of the chair was investigated through CFD simulations (ANSYS Fluent) providing a detailed analysis of the thermal distribution around a thermal chair with a manikin. Furthermore, a model of a three-story office building with thermal chairs were created and simulated in the commercial BES software, IES Virtual Environment. The benchmark model of the building was validated with previous work and good agreement was observed. The results showed that user thermal comfort can be enhanced by improving the local thermal comfort of the occupant. The additional plug-load energy from the thermal chair was significantly less as compared to the heating energy saved by adjusting the heating set point by 2°C during the heating season. Monthly heating energy demand was reduced by 27% on January and 25.4% on February. Furthermore, the results of the field study revealed 20% higher comfort and 35% higher satisfaction level, due to the use of thermal chair.
    • Analysis and design of cold-formed dimpled steel columns using Finite Element techniques

      Nguyen, Van Bac; Mynors, Diane; Wang, Chang; Castellucci, Michael; English, Martin; Hadley Industries plc; University of Sussex (Elsevier, 2015-10-21)
      Dimpled steel products are produced from the combination of an innovative dimpling process and a traditional forming process such as cold-roll forming or press-braking. The wider use of cold-formed dimpled steel members has promoted considerable interest in the local instability and strength of these members. Of particular interest is their buckling behaviour and ultimate strength capacity in columns under compressive loading. However, the dimpling process produces cold-formed sections with a complex ‘dimpled’ surface topography and the ‘dimpled’ material is non-uniformly work hardened through the entire thickness. Owing to these complex issues, there are no existing analytical and design methods to calculate the buckling strength of dimpled products and validate against physical measurements. This paper presents the analysis of the compressive behaviour of cold-formed channel and lipped channel dimpled steel columns using Finite Element techniques. True stress–strain data obtained from physical tests were incorporated into nonlinear simulations of dimpled steel columns. It was found that the predicted buckling and ultimate loads correlated well with the experimental results. Based on the validated Finite Element results for different geometries, standard design formulae for determining buckling and ultimate loads of channel and lipped channel dimpled columns were developed. It is demonstrated that the Finite Element Analysis can therefore be used to analyse and design cold-formed dimpled steel columns.
    • Analysis of the Impact of Urban Configuration on Road Solar Collectors.

      Nasir, Diana S. N. M.; Hughes, Ben; Calautit, John Kaiser; Shahzad, Sally; University of Sheffield; University of Derby (Applied Energy, 2016)
    • Anodised TiO 2 nanotubes as a scaffold for antibacterial silver nanoparticles on titanium implants.

      Gunputh, Urvashi Fowdar; Le, Huirong; Handy, Richard; Tredwin, Christopher; Plymouth University; University of Derby; Peninsula Dental School (Elsevier, 2018-05-28)
      Medical grade titanium alloy is widely used for bone/dental implants, but the material alone has no innate antimicrobial properties that would reduce infection risk following surgery. However, silver nanoparticles (Ag NPs) are known to be antibacterial. This study investigated the growth of Ag NPs on titanium dioxide nanotubes (TiO2 NTs) on Ti-6Al-4V discs. The TiO2 NTs were grown on the Ti alloy using an electrochemical method, and then decorated with Ag NPs. The Ag NPs were synthesised by chemical reduction using δ-gluconolactone. A silver ammonia solution (silver nitrate + liquid ammonia) was used as the source of silver. Two separate approaches were used: (1) The δ-gluconolactone was mixed with the silver ammonia and then exposed to the TiO2 NTs (the ‘mixing method’), which produced micron-sized clusters of the Ag NPs. (2) The TiO2 NTs were exposed to the silver ammonia first and then to δ-gluconolactone (the ‘sequential addition method’), which resulted in the formation of nano-sized clusters of the nanoparticles. The Ag-TiO2 composites were confirmed by scanning electron microscopy and the elements analysed using energy dispersive X-ray spectroscopy (EDS). The composite coatings were exposed to a simulated body fluid for 24 h in order to determine the total Ag released. The release from the micron-sized clusters from the mixing method (14.6 ± 0.67 ppm) was higher than that from the nano-sized clusters (4.05 ± 0.36 ppm) when 0.015 M of silver ammonia was used. Additionally, Staphylococcus aureus, was cultured on the composite coatings for 24 h. Both the micron- and nano-sized clusters of the Ag NPs were found to be antibacterial using the Live/Dead assay. Overall, δ-gluconolactone was successfully used to reduce silver to Ag NPs on the surface of TiO2 NTs. The sequential addition method was the preferred method of synthesis because of its slower silver release, better coverage of the Ag-NPs on the TiO2 NTs and strong antibacterial properties.
    • Antibacterial activity and biofilm inhibition by surface modified titanium alloy medical implants following application of silver, titanium dioxide and hydroxyapatite nanocoatings

      Besinis, Alexander; Hadi, Sanna Dara; Le, Huirong; Tredwin, Christopher; Handy, Richard; Plymouth University (Taylor and Francis, 2017-03-17)
      One of the most common causes of implant failure is peri-implantitis, which is caused by bacterial biofilm formation on the surfaces of dental implants. Modification of the surface nanotopography has been suggested to affect bacterial adherence to implants. Silver nanoparticles are also known for their antibacterial properties. In this study, titanium alloy implants were surface modified following silver plating, anodisation and sintering techniques to create a combination of silver, titanium dioxide and hydroxyapatite (HA) nanocoatings. Their antibacterial performance was quantitatively assessed by measuring the growth of Streptococcus sanguinis, proportion of live/dead cells and lactate production by the microbes over 24 h. Application of a dual layered silver–HA nanocoating to the surface of implants successfully inhibited bacterial growth in the surrounding media (100% mortality), whereas the formation of bacterial biofilm on the implant surfaces was reduced by 97.5%. Uncoated controls and titanium dioxide nanocoatings showed no antibacterial effect. Both silver and HA nanocoatings were found to be very stable in biological fluids with material loss, as a result of dissolution, to be less than 0.07% for the silver nanocoatings after 24 h in a modified Krebs-Ringer bicarbonate buffer. No dissolution was detected for the HA nanocoatings. Thus, application of a dual layered silver–HA nanocoating to titanium alloy implants creates a surface with antibiofilm properties without compromising the HA biocompatibility required for successful osseointegration and accelerated bone healing.
    • Antibacterial coating made of strongly adhered nanosilver to titania nanotubes for dental implants

      Danookdharree, Urvashi; Le, Huirong; Handy, Richard; Tredwin, Christopher; University of Plymouth; University of Derby (International Association for Dental Research, 2015-09-16)
      Objectives: An antibacterial and biocompatible coating on Ti-6Al-4V alloy was synthesised. A method of making the antibacterial effect long term, without any acute release of silver from a dental implant, on insertion was devised.Methods: Titania nanotubes were grown on Ti-6Al-4V alloy using anodisation in the presence of phosphate and fluoride ions. Following alkali treatment of the latter surface, silver nanoparticles were chemically reduced on the nanotubes. The latter surface was then characterised using high resolution electron microscopy (SEM) in association with energy dispersive X-Ray Spectroscopy (EDS) and Raman Spectroscopy. A silver release test was performed. Following a toxicity test in the presence of Human Osteoblast Cells, the biocompatibility of the coating would be assessed.Results: Initially, titania nanotubes with diameter of c. 100 nm were formed following the deposition of silver nanoparticles (10-25nm) on the outer and inner walls. The chemical structure of the nanoparticles was confirmed by Raman Spectroscopy and EDS. The results also highlighted the different bonding attaching the nanosilver to the walls. Subsequently a very low amount of silver was released from the coating during the beginning of the silver release test confirming a good adherence between the nanosilver and the nanotubes. The low leaching was expected to reduce the toxicity of the implant in general and it was confirmed by growth of human osteoblast cells on the coating.Conclusions: The strong adhesion of silver nanoparticles validated the fact that the coating on titanium alloy can prevent an acute release of silver as such having the possibility of having a long term antibacterial effects. This work gave rise to a novel method of synthesising an antibacterial coating for dental implants.
    • Antibacterial properties of silver nanoparticles grown in situ and anchored to titanium dioxide nanotubes on titanium implant against Staphylococcus aureus

      Gunputh, Urvashi F.; Le, Huirong; Lawton, Kiruthika; Besinis, Alexandros; Tredwin, Christopher; Handy, Richard D.; University of Derby; Plymouth University (Taylor & Francis, 2019-09-30)
      Medical grade titanium alloy, Ti-6Al-4V, with TiO2 nanotubes (TiO2-NTs) grown on the surface and then decorated with silver nanoparticles (Ag NPs) is proposed to enhance the antimicrobial properties of the bone/dental implants. However, the decoration with Ag NPs is not consistent and there are concerns about the direct contact of Ag NPs with human tissue. The aim of this study was to achieve a more even coverage of Ag NPs on TiO2-NTs and determine their biocidal properties against Staphylococcus aureus, with and without a top coat of nano hydroxyapatite (nHA). The decoration with Ag NPs was optimised by adjusting the incubation time of the TiO2-NTs in a silver ammonia solution, and using biocompatible δ-gluconolactone as a reducing agent. The optimum incubation in silver ammonia was 7 min, and resulted in evenly distributed Ag NPs with an average diameter of 47.5 ± 1.7 nm attached to the surface of the nanotubes. The addition of nHA did not compromise the antimicrobial properties of the materials; high-resolution electron microscopy showed S. aureus did not grow on the composite with nHA and with >80% biocidal activity measured by the LIVE/DEAD assay, also limited lactate production. Dialysis experiment confirmed the stability of the coatings, and showed a slow release of dissolved silver (3.27 ± 0.15 μg/L over 24 h) through the top coat of nHA.
    • Antimicrobial silver nanoparticles in titaniumdioxide nanotubes grown on Ti-6Al-4V medical grade alloy

      Danookdharree, Urvashi; Le, Huirong; University of Plymouth (Royal Society of Chemistry, 2015-03-23)
    • Assessment of unsteady-RANS approach against steady-RANS approach for predicting twin impinging jets in a cross-flow

      Yang, Zhiyin; University of Derby; Department of Engineering and Design, University of Sussex Brighton BN1 9RH UK (Cogent OA, 2014-07-31)
      A complex flow field is created when a vertical/short take-off and landing aircraft is operating near ground. One major concern for this kind of aircraft in ground effect is the possibility of ingestion of hot gases from the jet engine exhausts back into the engine, known as hot gas ingestion, which can increase the intake air temperature and also reduce the oxygen content in the intake air, potentially leading to compressor stall, low combustion efficiency and causing a dramatic loss of lift. This flow field can be represented by the configuration of twin impinging jets in a cross-flow. Accurate prediction of this complicated flow field under the Reynolds averaged Navier–Stokes (RANS) approach (current practise in industry) is a great challenge as previous studies suggest that some important flow features cannot be captured by the Steady-RANS (SRANS) approach even with a second-order Reynolds stress model (RSM). This paper presents a numerical study of this flow using the Unsteady-RANS (URANS) approach with a RSM and the results clearly indicate that the URANS approach is superior than the SRANS approach but still the predictions of Reynolds stress are not accurate enough.
    • Assessment of URANS approach for predicting twin impinging jets in a cross-flow

      Webb-Martin, S; Yang, Zhiyin; University of Derby (2012-07)
      A very complex flow field is present when a vertical/short take-off and landing (VSTOL) aircraft is operating in ground effect. One major concern for this kind of aircraft in ground effect is the possibility of ingestion of hot gases from the jet engine exhausts back into the engine, known as hot gas ingestion (HGI), which can increase the intake air temperature and also reduce the oxygen content in the intake air, potentially leading to compressor stall, low combustion efficiency and causing a dramatic loss of lift. It is therefore important for these flow features to be identified and modelled accurately through numerical simulations. This flow field can be represented by the configuration of twin impinging jets in a cross-flow. Accurate prediction of this complicated flow field under the Reynolds Averaged Navier-Stokes (RANS) approach (current practise in industry) is a great challenge as previous studies suggest that some important flow features cannot be captured by the Steady-RANS (SRANS) approach even with a second order Reynolds Stress Model (RSM). This paper presents a numerical study of this flow using the UnsteadyRANS approach (URANS) with a RSM and assess the capability of the URANS approach by comparing the results against the experimental data and the SRANS predictions.
    • Awarded architectural design of the Technology and Research Centre of Arsh Arak Co.

      Golmohammadi, M.; Fouladzari, Navaz; Shahzad, Sally; Azad University (2004)
    • Awarded architectural design of the Technology and Research Centre of Pargasiran Co.

      Golmohammadi, M.; Fouladzari, Navaz; Shahzad, Sally; Azad University (2004)
    • A benchmark analysis of subcooled heat transfer in a novel half-unit-cylinder-head for verifying in-vehicle engine evaporative cooling under dynamic conditions

      Langari, Mostafa; Dunne, Julian F.; Jafari, Soheil; Pirault, Jean-Pierre; Yang, Zhiyin; Long, Chris A.; Thalackottore Jose, Jisjoe; University of Sussex; University of Derby (2017-05-17)
      Evaporative cooling (EC) is a potentially attractive method of thermal management in highly downsized engines. As a benchmark for robust EC system development, a novel half-unit-cylinder-head has been designed to study the heat transfer achievable with evaporative cooling strategies under realistic hot metal conditions with an appropriate coolant flow field. Multi-phase computational fluid dynamics (CFD) and conjugate heat transfer (CHT) analysis are performed under subcooled flow boiling conditions to achieve both the design requirements for the hot-side surfaces and the specification of heating arrangements. Analysis is undertaken to ensure that thermal diffusion and flow conditions are representative of coolant flow in highly-boosted IC engines. The CFD model predictions show good correlation with available experimental data for both heat flux and metal temperatures in a typical downsized pressure-charged spark-ignition engine cylinder head.