• Stray alternating current (AC) induced corrosion of steel fibre reinforced concrete

      Tang, Kangkang (Elsevier, 2019-03-12)
      This paper primarily discusses the assessment of stray DC and AC-induced corrosion phenomena on steel fibres and the analysis of the main influencing parameters. Instrumental methods in electrochemistry including Tafel polarization, Cyclic Potentiodynamic (CP) polarization and Electrochemical Impedance Spectroscopy (EIS) were used to assess the corrosion resistance of steel fibres which has great potential to replace conventional steel reinforcement in railway tunnel construction. The analytical model based on electric circuit modelling indicates that concrete containing discrete steel fibres has an inherent corrosion resistance to stray AC interference due to the electrical double layer developed on the surface.
    • Stray current induced corrosion of steel fibre reinforced concrete

      Tang, Kangkang (Elsevier, 2017-08-18)
      Stray current induced corrosion is a major technical challenge for modern electric railway systems. The leakage of stray current to surrounding reinforced concrete structures can lead to steel reinforcement corrosion and the subsequent disintegration of concrete. Steel fibre reinforced concrete has been increasingly used as the railway tunnel lining material but it is not clear if discrete steel fibres can still pick up and transfer stray current in the same way as conventional steel reinforcement and lead to similar corrosion reactions. The corrosion behaviour of steel fibres was investigated through voltammetry tests and electrochemical impedance spectroscopy. The presence of high concentration chloride ions was found to increase the pitting corrosion tendency of steel fibres in simulated concrete pore solutions and mortar specimens. The chloride threshold level for corrosion of steel fibres in concrete is approximately 4% NaCl (by mass of cement) which is significantly higher than that of conventional steel reinforcement.
    • Streblo: the app prototype for managing stress in the construction industry

      Riva, Silvia; Hampton, Paul; Chinyio, Ezekiel (Springer/CITC Global, 2020-12-01)
      High levels of stress at work, great responsibilities, hazards and lack of balance between tasks and deadlines are common in the daily lives of many construction workers. Changing the patterns of thinking and behaviours is not an easy mission, and it requires constant support, learning and determination. E-health applications can contribute to this change through their ability to foster continuous interaction with the user. Mobile phone apps have shown promising results in the field of ‘e-health and wellbeing’. Accordingly, an App is being designed as a self-help system for stress management which will enable construction workers to 1) detect the onset of stress quite early, 2) track their stress status, 3) empower persons to cope with stressful and/or demanding situations in an adaptive way, 4) improve and streamline the operability of job tasks, and 5) optimise efficient solutions for the construction industry. The development of this innovative app, known as Streblo, is part of a wider research that is studying stress management in the construction industry. Streblo’s blueprint will match personality traits with coping strategies in real- life situations. Its inputs are being generated from a field study that has commenced, where 23 structured interviews have been used to collect data from construction workers on their 1) personality and 2) behaviours while experiencing stress. Results of the data collection and analysis are being used to develop Streblo (an App) with IT experts. The paper reports the detail development and performance of Streblo’s prototype. Ultimately, users will be able to engage Streblo on electronic devices (mobile phones, tablets, and computers) through both text and image-based communication obtain real-time solutions and feedbacks on their stress status. Streblo will enhance and support attitude and behavioural changes in people who suffer from stress symptoms in the construction industry.
    • Strength and stiffness properties of the optimum mix composition of cement-less wastepaper-based lightweight block (CWLB)

      Okeyinka, Oriyomi Modupe; Oloke, David; KHATIB JAMAL M (World Scientific and Engineering Academy and Society (WSEAS), 2017-08)
      The cement-less wastepaper-based lightweight block (CWLB) is a newly developed eco-friendly non-load bearing block manufactured from majorly cellulosic wastes without the use of cement. The main constituents of CWLB includes; wastepaper aggregate (WPA) produced from post-consumer wastepaper, waste additive and sand. This study was conducted to determine its optimum mix composition and the corresponding strength and stiffness properties. The experimentations carried out covered; the optimization of the mix composition of CWLB using the Taguchi statistical optimization technique (TSOT) and the determination of the compressive strength, density, elastic modulus and the ultrasonic pulse velocity (UPV) of the optimal CWLB specimen. The findings from the TSOT ascertains that the optimum mix composition of CWLB comprises of processing parameters including; 2.5 WPA/sand ratio, 0.75 water/binder ratio, and 3.5 Metric ton (i.e. 13.7 MPa) compacting force. Also, it was found that the optimal CWLB exhibited; an average compressive strength of 2.71 MPa, an average density of 901.5 kg/m3, an average UPV of 989.9 m/s and an estimated elastic modulus of 883.4 MPa. The comparison of these properties with the applicable standard requirements indicates the suitability of CWLB for non-load bearing application. In addition, the presence of 75% waste content in the mix composition of CWLB indicates its eco-friendliness and its potential to contribute to the sustainability in the construction industry through reduction in natural resources consumption. The innovation presented in this study includes; the development of a suitable optimum mix composition of constituent materials for the novel CWLB, the identification of factors that affects it strength properties and the determination of its engineering properties. Future work will investigate other relevant properties of CWLB which include; capillary water absorption, thermal conductivity, and the reaction to fire.
    • Strength by atomic force microscopy (AFM): Molecular dynamics of water layer squeezing on magnesium oxide

      Kendall, K.; Dhir, Aman; Yong, Chin W. (Taylor and Francis, 2009-11)
      Localised strength testing of materials is often carried out in an atomic force microscope (AFM), as foreseen by Kelly in his book Strong Solids (Clarendon Press, Oxford, 1966). During AFM indentation experiments, contamination can strongly influence the observed strength and theoretical interpretation of the results is a major problem. Here, we use molecular dynamics computer modelling to describe the contact of NaCl and MgO crystal probes onto surfaces, comparable to an AFM experiment. Clean NaCl gave elastic, brittle behaviour in contact simulations at 300 K, whereas MgO was more plastic, leading to increased toughness. This paper also considers the strength of an oxide substrate contaminated by water molecules and tested by indentation with a pyramidal probe of oxide crystal. Recent theory on the effect of liquid contaminant layers on surface strength has been mainly focussed on Lennard Jones (LJ) molecules with some studies on alcohols and water, described by molecular dynamics, which allows the molecules to be squeezed out as the crystal lattice is deformed. In this work, we have focused on water by studying the forces between a magnesium oxide (MgO) atomic force microscope (AFM) probe and an MgO slab. Force versus separation has been plotted as the AFM probe was moved towards and away from the substrate. Simulation results showed that the water layers could be removed in steps, giving up to four force peaks. The last monolayer of water could not be squeezed out, even at pressures where MgO deformed plastically. Interestingly, with water present, strength was reduced, but more in tensile than compressive measurements. In conclusion, water contaminating the oxide surface in AFM strength testing is structured. Water layer squeezing removal can be predicted by molecular modelling, which may be verified by AFM experiments to show that water can influence the strength of perfect crystals at the nanometre scale.
    • Strength curves for web crippling design of cold-formed stainless steel hat sections

      Bock, M.; Real, E. (Elsevier, 2014-09-02)
      The web crippling design guides are based on empirical adjustments of available test data. These equations differ from the basic concept underpinning most of the other instabilities, the so-called strength curves. This investigation presents a new design approach for web crippling design of stainless steel hat sections based on strength curves controlled by slenderness-based functions χ(). The effects of web crippling on such cross-sections were studied numerically and the obtained results were used to derive the design expressions. Comparisons with tests and FE data, and with design guides show that the proposed design approach provides more accurate web crippling resistance.
    • Stress and Coping Strategies: A Correlational Analysis to Profiling Maladaptive Behaviors at Work

      Riva, Silvia; Chinyio, Ezekiel (World Academy of Science Engineering and Technology, 2019-05-23)
      Introduction: Workers in different sectors are prone to stress at varying levels. They also respond to stress in different ways. An inspiration was to study stress development amongst workers in a work dangerous setting (Construction Industry) as well as how they cope with specific stress incidences. Objective: The overarching objective of the study was to study and correlate between stress and coping strategies. The research was conducted in an organizational industrial setting, and its findings on the coping actions of construction workers are reported in this article. Methods: An online cross-sectional survey was conducted with 80 participants aged 18-62. These were working for three different construction organizations in the West Midland region of the UK. Their coping actions were assessed using the COPE Inventory (Carver, 2013) instrument while the level of stress was assessed by the Perceived Stress Scale (Cohen, 1994). Results: Out of 80 workers (20 female, 25%, mean age 40.66), positive reinterpretation (M=4.15, SD=2.60) and active coping (M=4.18, SD=2.55) were the two most adaptive strategies reported by the workers while the most frequent maladaptive behavior was mental disengagement (M=3.62, SD=2.25). Among the maladaptive tactics, alcohol and drug abuse was a significant moderator in stress reactions (t=6.12, p=.000). Conclusion: Some maladaptive strategies are adopted by construction workers to cope with stress. So, it could be argued that programs of stress prevention and control in the construction industry have a basis to develop solutions that can improve and strengthen effective interventions when workers are stressed or getting stressed.
    • Stress factors and stress management interventions: the heuristic of “bottom up” an update from a systematic review

      Riva, Silvia; Chinyio, Ezekiel (Springer, 2018-03-30)
      Organizations have increasingly sought to adopt innovative interventions to prevent stress-related issues. In the field of manufacturing, however, the effectiveness of these interventions remains unclear because a systematic and specific review of existing primary evidence has not been undertaken. The present systematic literature review sought to address the foregoing limitation in the literature by summarizing the main source of stress and effectiveness of stress management interventions as grounded in the context of manufacturing. Our review was limited to only randomized clinical trials (RCTs) and quasi-experimental studies and concerned employees from the manufacturing sector. Twenty-two studies on primary, secondary and tertiary interventions across four continents (Asia, Europe, USA and South America) were selected and analyzed in terms of stress factors, methodological properties and outcomes. Most of these were RCT studies (68% Vs 32%) with a majority of secondary interventions (N = 11, 50%), followed by primary (N = 5, 22%), tertiary (N = 3, 13%), and two (9%) mixed interventions. The main outcomes included an improvement of psychological wellbeing, decreased stress reactivity and an increment of general health. There was a predominance of interventions utilizing skills programs and/or cognitive-behavioral techniques. The main source of stress reported related to professional identity, organizational deficiencies, interpersonal conflicts, physical complaints and poor work environment. Taken together, the findings provide important theoretical and practical implications for advancing the study of stress factors and the use of stress management interventions in the workplace. The prerequisite for a successful intervention is to address the real problems experienced by professionals and help them to cope with their difficult situations. The strategy of “bottom-up” offers a potential means of enhancing employees’ health and well-being; however, the most effective means of implementing these interventions needs to be understood better.
    • Stress levels during the journey of cancer treatment

      Khan, Umer; Morrissey, Hana; Ball, Patrick (National Wellbeing Services, 2017-12-31)
      A patient’s journey with cancer may cause psychological disorders or exacerbate existing conditions. The field of psycho-oncology has found ways to link psychological disorders to cancer and research the effects of mental disorders on patient outcome and wellbeing. This review looked at current literature in the field of psycho-oncology to understand how the stress level changes during the patient’s treatment journey. A search was performed to identify relevant published articles on electronic databases, including PubMed, ScienceDirect and Web of Science. The results demonstrate a direct link between cancer diagnosis and increased stress, depression and anxiety within patients, not as medication side-effects. These levels reduce over time, mainly due to patient acceptance coupled with either improved prognosis, or acceptance of death. Stress is complex and can precipitate a range of psychological disorders. Early psychological, counselling and even in some cases coaching interventions, could work preventively to help cancer patients more effectively to manage their stress, thereby promoting their greater wellbeing. Additionally, early diagnosis of mental disorders is crucial to improving long-term outcomes, therefore, the need for adequate psychological screening services in oncology patients for mental illness should be routine practice.
    • A striking new species of Papuan groundsnake (Stegonotus: Colubridae) from southern Papua New Guinea, with a dichotomous key to the genus in New Guinea

      O'Shea, Mark; Richards, Stephen J (Magnolia Press, 2021-02-04)
      We describe a new species of groundsnake of the genus Stegonotus (Colubridae) from the Purari River basin in Gulf Province, Papua New Guinea. The new species can be most readily distinguished from all other New Guinean Stegonotus by its unique dorsal colour pattern which consists of a dark head and creamy-white anterior one third to two thirds of the body, grading into increasingly dense dark pigmentation on the posterior of the body and tail. It is most similar to S. iridis from the Raja Ampat Archipelago off western New Guinea, but that species has a different pattern of pigmentation dorsally, has a lower ventral scale count (198–211 vs. 229–239), and exhibits a different temporal scale arrangement. The description of S. aplini sp. nov. brings to fourteen the number of Stegonotus species described from New Guinea. A dichotomous key to described species in the New Guinea region is provided.
    • Stroke: Twist in artery linked to stroke in young adults

      Patel, Mitesh (Springer, 2017-08-17)
      Dolichoectasia, a condition of unknown cause characterized by elongation, twisting and dilation of the basilar artery in old age, is common among young patients admitted for acute stroke, a new study shows. This finding highlights the need to consider vascular abnormalities as a risk factor for stroke in young adults.
    • Structural behaviour of reinforced concrete beams containing a novel lightweight aggregate

      Herki, Bengin Masih Awdel; Khatib, Jamal M. (Inderscience publishers (IEL), 2015-12-15)
      This paper reports the results of an experimental investigation into the structural behaviour of reinforced concrete beams incorporating a novel EPS-based lightweight aggregate (LWA) called stabilised polystyrene (SPS) aggregate. Four concrete mixtures with water to cement (W/C) ratio of 0.8 were used. The replacement levels of natural aggregate by SPS were 0%, 30%, 60% and 100%. The volume ratio to manufacture SPS aggregate was 8:1:1 (80% waste EPS: 10% cement: 10% clay). A total of 24 beams were cast and tested at 28-day age. Three types of tension reinforcement were used: 2 bars, 3 bars and 2 bars + shear links. There were no compression bars at the top for all beams. Four point-loading flexural tests were conducted up to failure. In general, it can be observed that the structural behaviour of SPS concrete beams is similar to that of other types of lightweight aggregate concretes used around the world.
    • Structural determinants of oligomerization of the aquaporin-4 channel

      Kitchen, P; Conner, MT; Bill, RM; Conner, AC; From the Molecular Assembly and Organisation in Cells Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, the School of Life & Health Sciences and Aston Research Centre for Healthy Ageing, Aston University, Aston Triangle, Birmingham, B4 7ET, and the Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. (American Society for Biochemistry & Molecular Biology (ASBMB), 2016-01-19)
      ©2016 by The American Society for Biochemistry and Molecular Biology, Inc. The aquaporin (AQP) family of integral membrane protein channels mediate cellular water and solute flow. Although qualitative and quantitative differences in channel permeability, selectivity, subcellular localization, and trafficking responses have been observed for different members of the AQP family, the signature homotetrameric quaternary structure is conserved. Using a variety of biophysical techniques, we show that mutations to an intracellular loop (loop D) of human AQP4 reduce oligomerization. Non-tetrameric AQP4 mutants are unable to relocalize to the plasma membrane in response to changes in extracellular tonicity, despite equivalent constitutive surface expression levels and water permeability to wild-type AQP4. A network of AQP4 loop D hydrogen bonding interactions, identified using molecular dynamics simulations and based on a comparative mutagenic analysis of AQPs 1, 3, and 4, suggest that loop D interactions may provide a general structural framework for tetrameric assembly within theAQPfamily.
    • Structural response of cold-formed lipped Z purlins – Part 2 numerical modelling and optimisation of lip size

      Almatrafi, Meshal; Theofanous, Marios; Dirar, Samir; Bock, Marina (Elsevier, 2021-01-23)
      This paper reports a numerical study on the optimisation of the lip size of Z-sections under gravity loads. Numerical models of cold-formed steel Z purlins restrained by cladding and angle struts and subjected to sagging moment were developed and validated against a total of 8 experimental results on Z-sections that failed in local or/and distortional buckling reported in the companion paper. Models of varying levels of complexity were generated and the key parameters affecting the structural response were determined by means of a sensitivity analysis. The investigated parameters included the magnitude, shape and combination of initial geometric imperfections pertinent to local and distortional buckling and the simplified or explicit modelling of test details such as struts and sheeting. Having determined the appropriate modelling strategy that leads to the best balance between accuracy and computational cost, parametric studies were conducted to investigate the effect of decreasing or increasing the lip depth on the sections’ moment resistance and corresponding failure mode. Based on the parametric study results, the optimal lip size which maximizes the moment to weight ratio for each section was determined. Finally, all generated FE results are utilized to evaluate the accuracy of the moment resistance prediction of EN 1993-1-3 and the Direct Strength Method.
    • Structure investigation of nano-FeO(OH) modified clinoptilolite tuff for antimony removal

      Chmielewská, E.; Tylus, W.; Drábik, M.; Majzlan, J.; Kravčak, J.; Williams, Craig; Čaplovičová, M.; Čaplovič, Ľ. (Elsevier, 2017-04-14)
      Biomimetic sol-gel synthesis was used to prepare new FeO(OH) zeolite (clinoptilolite tuff) adsorbent effective for antimony removal. The product was compared with other on the market accessible natural or commercial adsorption materials like granulated ferric hydroxide GEH, powder of zero valent iron (ZVI)- nanofer and the new synthesized oxi(hydr)oxide FeO(OH) and characterized by XRD, XPS, Raman, FT IR, TG, DTA, DTG, TEM and SEM techniques. Based upon the SEM analysis, the oxidized nanofer sample revealed the existence of hematite and goethite and morphology of FeO(OH) dopant confirmed the presence of ferrihydrite, in less extent also magnetite and hematite. Recorded exothermic maxima on DTA curves for powdered FeO(OH) zeolite at 460 °C and for pure component FeO(OH) at 560 °C indicated an 100 °C shifted exothermic effect, which characterized strong chemical interaction of FeO(OH) with zeolite structure. Based upon the XPS analyses, also the difference between Fe species in the raw and FeO(OH) doped zeolite was found in increasing Si/Al ratio, however only at the surface below app. 5 nm, measured as 3.94 for raw and 5.38 for sample treated with alkalic solution. The plotting of adsorption isotherms in the system studied clearly showed the increasing uptake capacity of the adsorbents towards antimony with the increased S(BET) data (GEH ˃FeO(OH)˃FeO(OH) zeolite˃nanofer).
    • Structure of the harmonic oscillator in the space of n-particle Glauber correlators

      Zubizarreta Casalengua, E.; López Carreño, J. C.; del Valle, E.; Laussy, Fabrice; Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain; Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain; Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain; Faculty of Science Engineering, University of Wolverhampton, Wulfruna St., Wolverhampton WV1 1LY, United Kingdom (AIP, 2017-06-27)
      We map the Hilbert space of the quantum harmonic oscillator to the space of Glauber’s nth-order intensity correlators, in effect showing “the correlations between the correlators” for a random sampling of the quantum states. In particular, we show how the popular g(2) function is correlated to the mean population and how a recurrent criterion to identify single-particle states or emitters, namely, g(2)<1/2g(2)<1/2, actually identifies states with at most two particles on average. Our charting of the Hilbert space allows us to capture its structure in a simpler and physically more intuitive way that can be used to classify quantum sources by surveying which territory they can access.
    • Study of some inorganic oxyanion-loaded ODA and Ag Clinoptilolite-rich tuff by HR TEM, SEM and XRD spectral analytical techniques.

      Chmielewska, E.; Bogdanchikova, Nina; Williams, Craig D. (Wroclaw University of Technology, 2004)
    • A study to explore learning style preferences of pharmacy students with regard to pharmaceutical calculations

      Wara, Bahta; Daly, Jan; Morrissey, Hana; Ball, Patrick (International Journal of Current Pharmaceutical Research, 2019-07-17)
      Objective: Pharmaceutical calculations are an essential aspect of learning for pharmacy students in order to avoid drug dose errors and maintain patient safety in future practice. Learning styles influence how lecturers approach the teaching-learning process. So far no specific learning preference is believed to be most appropriate for the pharmacy curricular; however certain learning styles are favoured by students as they improve their understanding of course material, knowledge and performance. Methods: 148Master of pharmacy participants from the second and third year were given a questionnaire to complete during a compulsory Individual Readiness Assurance Test session. Participants were restricted to just one option. Results: Workshops with a tutor was the most selected (36%) followed by 25% of participants favouring formative assessments, 28% selected workbooks alone, 37% for whole-class lecturers and videos option was the least selected. Reasons for the most and least preferred learning styles were highlighted and separated into advantages and disadvantages using themes. In the knowledge test; 92% of participants selected “unsure” or “didn’t know” the answer, 29% had a partially correct answer and 19% selected incorrect answers. The overall order of ranking arose in regards to the most beneficial learning style which enhances performance. The responses revealed a variety of advantages and disadvantages which were reflected between year groups and similar to views obtained from recent literature. Students reflected a lack of understanding on extemporaneous preparation (EPs) terms used in pharmaceutical compounding practices, thus the university should consider addressing the lack of awareness and consider the best teaching-learning style in doing so. Conclusion: Overall the findings suggested that the sample students have similar views on the learning styles used to deliver pharmaceutical calculations on their academic performance to that expressed by the authors from recent published literature.
    • Styles of learning engendered by different approaches to work-based learning: a comparative study

      Davies, Jenny; Harris, Phil; Crossland, Glenys (University of Wolverhampton, 2004)
      Work-based learning is increasingly being implemented in higher education; the overall intention of this research project was to explore the quality of learning engendered by this experience with a view to identifying and characterising those facets which would enhance the students'learning.