Abstract: The importance of fibre reinforced plastics continually
increases due to the excellent mechanical properties, low material
and manufacturing costs combined with significant weight reduction.
Today, components are usually designed and calculated numerically
by using finite element methods (FEM) to avoid expensive laboratory
tests. These programs are based on material models including
material specific deformation characteristics. In this research project,
material models for short glass fibre reinforced plastics are presented
to simulate the visco-elasto-plastic deformation behaviour. Prior
to modelling specimens of the material EMS Grivory HTV-5H1,
consisting of a Polyphthalamide matrix reinforced by 50wt.-% of
short glass fibres, are characterized experimentally in terms of
the highly time dependent deformation behaviour of the matrix
material. To minimize the experimental effort, the cyclic deformation
behaviour under tensile and compressive loading (R = −1) is
characterized by isothermal complex low cycle fatigue (CLCF)
tests. Combining cycles under two strain amplitudes and strain
rates within three orders of magnitude and relaxation intervals
into one experiment the visco-elastic deformation is characterized.
To identify visco-plastic deformation monotonous tensile tests
either displacement controlled or strain controlled (CERT) are
compared. All relevant modelling parameters for this complex
superposition of simultaneously varying mechanical loadings are
quantified by these experiments. Subsequently, two different material
models are compared with respect to their accuracy describing the
visco-elasto-plastic deformation behaviour. First, based on Chaboche
an extended 12 parameter model (EVP-KV2) is used to model cyclic
visco-elasto-plasticity at two time scales. The parameters of the
model including a total separation of elastic and plastic deformation
are obtained by computational optimization using an evolutionary
algorithm based on a fitness function called genetic algorithm.
Second, the 12 parameter visco-elasto-plastic material model by
Launay is used. In detail, the model contains a different type of a
flow function based on the definition of the visco-plastic deformation
as a part of the overall deformation. The accuracy of the models is
verified by corresponding experimental LCF testing.
Abstract: In this study, a comprehensive approach has been adopted to examine in detail the effect of various hook geometries on bond-slip characteristics. Extensive single fibre pull-out tests on ultra-high performance matrix with three different W/B ratios and embedded lengths have been carried out. Test results showed that the mechanical deformation of fibre hook is the main mechanism governing the pull-out behaviour. Furthermore, the quantitative analyses have been completed to compare the hook design contribution of 3D, 4D and 5D fibres to assess overall pull-out behaviour. It was also revealed that there is a strong relationship between the magnitude of hook contribution and W/B ratio (i.e. matrix strength). Reducing the W/B ratio from 0.20 to 0.11 greatly optimizes the interfacial transition zone (ITZ) and enables better mobilization, straightening of the hook and results in bond-slip-hardening behaviour.
Abstract: This work investigates upsetting of the tri-metallic cylindrical billets both experimentally and analytically with a reduction ratio 30%. Steel, brass, and copper are used for the outer and outmost rings and aluminum for the inner core. Two different models have been designed to show material flow and the cavity took place over the two interfaces during forming after this reduction ratio. Each model has an outmost ring material as steel. Model 1 has an outer ring between the outmost ring and the solid core material as copper and Model 2 has a material as brass. Solid core is aluminum for each model. Billets were upset in press machine by using parallel flat dies. Upsetting load was recorded and compared for models and single billets. To extend the tests and compare with experimental procedure to a wider range of inner core and outer ring geometries, finite element model was performed. ABAQUS software was used for the simulations. The aim is to show how contact between outmost ring, outer ring and the inner core are carried on throughout the upsetting process. Results have shown that, with changing in height, between outmost ring, outer ring and inner core, the Model 1 and Model 2 had very good interaction, and the contact surfaces of models had various interface behaviour. It is also observed that tri-metallic materials have lower weight but better mechanical properties than single materials. This can give an idea for using and producing these new materials for different purposes.
Abstract: Many schools throughout the world are facing constant pressure to cope with the violence and drug abuse of learners who show little or no respect for acceptable and desirable social norms. These delinquent learners tend to harbour feelings of being beyond reproach because they strongly believe that it is well within their rights to engage in violent and destructive behaviour. Knives, guns, and other weapons appear to be more readily used by them on the school premises than before. It is known that learners smoke, drink alcohol, and use drugs during school hours, hence, their ability to concentrate, work, and learn, is affected. They become violent and display disruptive behaviour in their classrooms as well as on the school premises, and this atrocious behaviour makes it possible for drug dealers and gangsters to gain access onto the school premises. The primary purpose of this exploratory quantitative study was therefore to establish how tobephobia (TBP), caused by school violence and drug abuse, affects teaching and learning in schools. The findings of this study affirmed that poor discipline resulted in producing poor quality education. Most of the teachers in this study agreed that educating learners who consumed alcohol and other drugs on the school premises resulted in them suffering from TBP. These learners are frequently abusive and disrespectful, and resort to violence to seek attention. As a result, teachers feel extremely demotivated and suffer from high levels of anxiety and stress. The word TBP will surely be regarded as a blessing by many teachers throughout the world because finally, there is a word that will make people sit up and listen to their problems that cause real fear and anxiety in schools.
Abstract: The parallel usage of different media channels has increased recently owing to technological advances. Second Screen describes the use of a second device by television viewers to consume further content which is related to the program they are watching. This study analysed the characteristics of football spectators regarding their media consumption in relation to Second Screen usage while watching a football match on TV. The existing literature on Second Screen usage is still very limited, especially in the context of particular broadcasting settings such as sport or even more specific such as football matches. Therefore, the primary research objective was to reveal first insights into the user behaviour of football spectators regarding Second Screen services. The survey, which was conducted among German football supporters in 2015, revealed some characteristics such as the identification and involvement into the sports which are related to an increased use of Second Screen services. One important finding for football supporters was that at the time of a match they have a lower parallel media usage compared to other TV broadcastings. Nevertheless, if supporters used a second device while watching a match on TV, then they were using specific Second Screen services. This means they searched for more content related information. The findings on the habits and characteristics of people who are using Second Screen services are relevant for future developments in that area as well as for marketing decisions.
Abstract: Superhydrophobic surfaces are abundant in nature. Several surfaces such as wings of butterfly, legs of water strider, feet of gecko and the lotus leaf show extreme water repellence behaviour. Self-cleaning, stain-free fabrics, spill-resistant protective wears, drag reduction in micro-fluidic devices etc. are few applications of superhydrophobic surfaces. In order to design robust superhydrophobic surface, it is important to understand the interaction of water with superhydrophobic surface textures. In this work, we report a simple coating method for creating large-scale flexible superhydrophobic paper surface. The surface consists of multiple layers of silanized zirconia microparticles decorated with zirconia nanoparticles. Water contact angle as high as 159±10 and contact angle hysteresis less than 80 was observed. Drop impact studies on superhydrophobic paper surface were carried out by impinging water droplet and capturing its dynamics through high speed imaging. During the drop impact, the Weber number was varied from 20 to 80 by altering the impact velocity of the drop and the parameters such as contact time, normalized spread diameter were obtained. In contrast to earlier literature reports, we observed contact time to be dependent on impact velocity on superhydrophobic surface. Total contact time was split into two components as spread time and recoil time. The recoil time was found to be dependent on the impact velocity while the spread time on the surface did not show much variation with the impact velocity. Further, normalized spreading parameter was found to increase with increase in impact velocity.
Abstract: Understanding the stability of rail ballast is one of the most important aspects in the railways. An unstable track may cause some issues such as unnecessary vibration and ultimately loss of track quality. The track foundation plays an important role in the stabilization of the railway. The dynamic response of rail ballast in the vicinity of the rail sleeper can affect the stability of the rail track and this has not been studied in detail. A review of literature showed that most of the works focused on the area under the concrete sleeper. Although there are some theories about the shear (longitudinal) effect of the rail ballast, these have not properly been studied and hence are not well understood. The stability of a rail track will depend on the compactness of the ballast in its vicinity. This paper will try to determine the dynamic response of the ballast to identify its resonant behaviour. This preliminary research is one of several studies that examine the vibration response of the granular materials. The main aim is to use this information for future design of sleepers to ensure that any dynamic response of the sleeper will not compromise the state of compactness of the ballast. This paper will report on the dependence of damping and the natural frequency of the ballast as a function of depth and distance from the point of excitation introduced through a concrete block. The concrete block is used to simulate a sleeper and the ballast is simulated with gravel. In spite of these approximations, the results presented in the paper will show an agreement with theories and the assumptions that are used in study the mechanical behaviour of the rail ballast.
Abstract: This paper presents the data of a series of two-dimensional Discrete Element Method (DEM) simulations of a large-diameter rigid monopile subjected to cyclic loading under a high gravitational force. At present, monopile foundations are widely used to support the tall and heavy wind turbines, which are also subjected to significant from wind and wave actions. A safe design must address issues such as rotations and changes in soil stiffness subject to these loadings conditions. Design guidance on the issue is limited, so are the availability of laboratory and field test data. The interpretation of these results in sand, such as the relation between loading and displacement, relies mainly on empirical correlations to pile properties. Regarding numerical models, most data from Finite Element Method (FEM) can be found. They are not comprehensive, and most of the FEM results are sensitive to input parameters. The micro scale behaviour could change the mechanism of the soil-structure interaction. A DEM model was used in this paper to study the cyclic lateral loads behaviour. A non-dimensional framework is presented and applied to interpret the simulation results. The DEM data compares well with various set of published experimental centrifuge model test data in terms of lateral deflection. The accumulated permanent pile lateral displacements induced by the cyclic lateral loads were found to be dependent on the characteristics of the applied cyclic load, such as the extent of the loading magnitudes and directions.
Abstract: This experimental study consists of a characterization
of epoxy grout where an amount of 2% of graphene nanoplatelets
particles were added to commercial epoxy resin to evaluate their
behavior regarding neat epoxy resin. Compressive tests, tensile tests
and flexural tests were conducted to study the effect of graphene
nanoplatelets on neat epoxy resin. By comparing graphene-based and
neat epoxy grout, there is no significant increase of strength due to
weak interface in the graphene nanoplatelets/epoxy composites.
From this experiment, the tension and flexural strength of graphenebased
epoxy grouts is slightly lower than ones of neat epoxy grout.
Nevertheless, the addition of graphene has produced more consistent
results according to a smaller standard deviation of strength.
Furthermore, the graphene has also improved the ductility of the
grout, hence reducing its brittle behaviour. This shows that the
performance of graphene-based grout is reliably predictable and able
to minimise sudden rupture. This is important since repair design of
damaged pipeline is of deterministic nature.
Abstract: Adoption of Information Systems (IS) is receiving
increasing attention such that its implications have been closely
monitored and studied by the IS management community, industry
and professional gatekeepers. Building on previous research
regarding the adoption of technology, this paper develops and
validates an integrated model of the adoption of mobile banking. The
model originates from the Technology Acceptance Model (TAM) and
the Theory of Planned Behaviour (TPB). This paper intends to offer a
preliminary scrutiny of the antecedents of the adoption of mobile
banking services in the context of a developing country. Data was
collected from Pakistan. The findings showed that an integrated TAM
and TPB model greatly explains the adoption intention of mobile
banking; and perceived behavioural control and its antecedents play a
significant role in predicting adoption Theoretical and managerial
implications of findings are presented and discussed.
Abstract: In this paper, we describe the use of formal methods
to model malware behaviour. The modelling of harmful behaviour
rests upon syntactic structures that represent malicious procedures
inside malware. The malicious activities are modelled by a formal
grammar, where API calls’ components are the terminals and the set
of API calls used in combination to achieve a goal are designated
non-terminals. The combination of different non-terminals in various
ways and tiers make up the attack vectors that are used by harmful
software. Based on these syntactic structures a parser can be
generated which takes execution traces as input for pattern
recognition.
Abstract: The aim of the present study is to investigate
consumers' determinants of intention toward the adoption of Smart
Grid solutions and technologies. Ajzen's Theory of Planned
Behaviour (TPB) model is applied and tested to explain the formation
of such adoption intention. An exogenous variable, taking into
account the resistance to change of individuals, was added to the
basic model. The elicitation study allowed obtaining salient modal
beliefs, which were used, with the support of literature, to design the
questionnaire. After the screening phase, data collected from the
main survey were analysed for evaluating measurement model's
reliability and validity. Consistent with the theory, the results of
structural equation analysis revealed that attitude, subjective norm,
and perceived behavioural control positively, which affected the
adoption intention. Specifically, the variable with the highest estimate
loading factor was found to be the perceived behavioural control,
and, the most important belief related to each construct was
determined (e.g., energy saving was observed to be the most
significant belief linked with attitude). Further investigation indicated
that the added exogenous variable has a negative influence on
intention; this finding confirmed partially the hypothesis, since this
influence was indirect: such relationship was mediated by attitude.
Implications and suggestions for future research are discussed.
Abstract: Psychopathic disorders are taking an important part in
judge sentencing, especially in Canada. First, we will see how this
phenomenon can be illustrated by the high proportion of psychopath
offenders incarcerated in North American prisons. Many decisions in
Canadians courtrooms seem to point out that psychopathy is often
used as a strong argument by the judges to preserve public safety.
The fact that psychopathy is often associated with violence,
recklessness and recidivism, could explain why many judges consider
psychopathic disorders as an aggravating factor. Generally, the judge
reasoning is based on Article 753 of Canadian Criminal Code related
to dangerous offenders, which is used for individuals who show a
pattern of repetitive and persistent aggressive behaviour. Then we
will show how, with cognitive neurosciences, the psychopath’s
situation in courtrooms would probably change. Cerebral imaging
and news data provided by the neurosciences show that emotional
and volitional functions in psychopath’s brains are impaired.
Understanding these new issues could enable some judges to
recognize psychopathic disorders as a mitigating factor. Finally, two
important questions ought to be raised in this article: can exploring
psychopaths ‘brains really change the judge sentencing in Canadian
courtrooms? If yes, can judges consider psychopathy more as a
mitigating factor than an aggravating factor?
Abstract: This paper presents the experimental investigation on
the bond behavior of geo polymer concrete. The bond behavior of
geo polymer concrete cubes of grade M35 reinforced with 16 mm
TMT rod is analyzed. The results indicate that the bond performance
of reinforced geo polymer concrete is good and thus proves its
application for construction.
Abstract: The objective of the article was to identify the impacts of gamification on customers' behaviour. The most important applications of games in marketing and mechanisms of gamification are presented in the article. A detailed analysis of the influence of gamification on customers using two brands, Foursquare and Nike, was also presented. Research studies using auditory survey methods were carried out among 176 young respondents, who are potential targets of gamification. The studies confirmed a huge participation of young people in customer loyalty programs with relatively low participation in other gamificationbased marketing activities. The research findings clearly indicate that gamification mechanisms are the most attractive.
Abstract: In the past researchers have questioned the
effectiveness of ethics training in higher education. Also, there are
observations that support the view that ethical behaviour (range of
actions)/ethical decision making models used in the past make use of
vignettes to explain ethical behaviour. The understanding remains in
the perspective that these vignettes play a limited role in determining
individual intentions and not actions. Some authors have also agreed
that there are possibilities of differences in one’s intentions and
actions. This paper makes an attempt to fill those gaps by evaluating
real actions rather than intentions. In a way this study suggests the
use of an experiential methodology to explore Berlo’s model of
communication as an action along with orchestration of various
principles. To this endeavor, an attempt was made to use
conversational analysis in the pursuance of evaluating ethical
decision making behaviour among students and middle level
managers. The process was repeated six times with the set of an
average of 15 participants. Similarities have been observed in the
behaviour of students and middle level managers that calls for
understanding that both the groups of individuals have no cognizance
of their actual actions. The deliberations derived out of conversation
were taken a step forward for meta-ethical evaluations to portray a
clear picture of ethical behaviour among participants. This study
provides insights for understanding demonstrated unconscious human
behaviour which may fortuitously be termed both ethical and
unethical.
Abstract: The wear measuring and wear modelling are
fundamental issues in the industrial field, mainly correlated to the
economy and safety. Therefore, there is a need to study the wear
measurements and wear estimation. Pin-on-disc test is the most
common test which is used to study the wear behaviour. In this paper,
the pin-on-disc (AEROTECH UNIDEX 11) is used for the
investigation of the effects of normal load and hardness of material on
the wear under dry and sliding conditions. In the pin-on-disc rig, two
specimens were used; one, a pin is made of steel with a tip, positioned
perpendicular to the disc, where the disc is made of aluminium. The
pin wear and disc wear were measured by using the following
instruments: The Talysurf instrument, a digital microscope, and the
alicona instrument. The Talysurf profilometer was used to measure
the pin/disc wear scar depth, digital microscope was used to measure
the diameter and width of wear scar, and the alicona was used to
measure the pin wear and disc wear. After that, the Archard model,
American Society for Testing and Materials model (ASTM), and
neural network model were used for pin/disc wear modelling.
Simulation results were implemented by using the Matlab program.
This paper focuses on how the alicona can be used for wear
measurements and how the neural network can be used for wear
estimation.
Abstract: This paper presents the details of a numerical study of
buckling and post buckling behaviour of laminated carbon fiber
reinforced plastic (CFRP) thin-walled cylindrical shell under axial
compression using asymmetric meshing technique (AMT) by
ABAQUS. AMT is considered to be a new perturbation method to
introduce disturbance without changing geometry, boundary
conditions or loading conditions. Asymmetric meshing affects both
predicted buckling load and buckling mode shapes. Cylindrical shell
having lay-up orientation [0^o/+45^o/-45^o/0^o] with radius to thickness
ratio (R/t) equal to 265 and length to radius ratio (L/R) equal to 1.5 is
analysed numerically. A series of numerical simulations
(experiments) are carried out with symmetric and asymmetric
meshing to study the effect of asymmetric meshing on predicted
buckling behaviour. Asymmetric meshing technique is employed in
both axial direction and circumferential direction separately using
two different methods, first by changing the shell element size and
varying the total number elements, and second by varying the shell
element size and keeping total number of elements constant. The
results of linear analysis (Eigenvalue analysis) and non-linear
analysis (Riks analysis) using symmetric meshing agree well with
analytical results. The results of numerical analysis are presented in
form of non-dimensional load factor, which is the ratio of buckling
load using asymmetric meshing technique to buckling load using
symmetric meshing technique. Using AMT, load factor has about 2%
variation for linear eigenvalue analysis and about 2% variation for
non-linear Riks analysis. The behaviour of load end-shortening curve
for pre-buckling is same for both symmetric and asymmetric meshing
but for asymmetric meshing curve behaviour in post-buckling
becomes extraordinarily complex. The major conclusions are:
different methods of AMT have small influence on predicted
buckling load and significant influence on load displacement curve
behaviour in post buckling; AMT in axial direction and AMT in
circumferential direction have different influence on buckling load
and load displacement curve in post-buckling.
Abstract: The study of organisations’ information security
cultures has attracted scholars as well as healthcare services industry
to research the topic and find appropriate tools and approaches to
develop a positive culture. The vast majority of studies in Saudi
national health services are on the use of technology to protect and
secure health services information. On the other hand, there is a lack
of research on the role and impact of an organisation’s cultural
dimensions on information security. This research investigated and
analysed the role and impact of cultural dimensions on information
security in Saudi Arabia health service. Hypotheses were tested and
two surveys were carried out in order to collect data and information
from three major hospitals in Saudi Arabia (SA). The first survey
identified the main cultural-dimension problems in SA health
services and developed an initial information security culture
framework model. The second survey evaluated and tested the
developed framework model to test its usefulness, reliability and
applicability. The model is based on human behaviour theory, where
the individual’s attitude is the key element of the individual’s
intention to behave as well as of his or her actual behaviour. The
research identified a set of cultural and sub-cultural dimensions in SA
health information security and services.
Abstract: Iris codes contain bits with different entropy. This
work investigates different strategies to reduce the size of iris
code templates with the aim of reducing storage requirements and
computational demand in the matching process. Besides simple subsampling
schemes, also a binary multi-resolution representation as
used in the JBIG hierarchical coding mode is assessed. We find that
iris code template size can be reduced significantly while maintaining
recognition accuracy. Besides, we propose a two-stage identification
approach, using small-sized iris code templates in a pre-selection
stage, and full resolution templates for final identification, which
shows promising recognition behaviour.