Abstract: Solid fuel transient burning behavior under oxidizer
gas flow is numerically investigated. It is done using analysis of the
regression rate responses to the imposed sudden and oscillatory
variation at inflow properties. The conjugate problem is considered
by simultaneous solution of flow and solid phase governing
equations to compute the fuel regression rate. The advection
upstream splitting method is used as flow computational scheme in
finite volume method. The ignition phase is completely simulated to
obtain the exact initial condition for response analysis. The results
show that the transient burning effects which lead to the combustion
instabilities and intermittent extinctions could be observed in solid
fuels as the solid propellants.
Abstract: It well recognized that one feature that makes a
successful company is its ability to successfully align its business goals with its information communication technologies platform.
Enterprise Resource Planning (ERP) systems contribute to achieve better performance by integrating various business functions and
providing support for information flows. However, the technological
systems complexity is known to prevent the business users to exploit in an efficient way the Enterprise Resource Planning Systems (ERP).
This paper aims to investigate the role of training in improving the
usage of ERP systems. To this end, we have designed an instrument
survey to employees of a Norwegian multinational global provider of
technology solutions. Based on the analysis of collected data, we have delineated a training model that could be high relevance for
both researchers and practitioners as a step towards a better
understanding of ERP system implementation.
Abstract: This paper present the harmonic elimination of hybrid
multilevel inverters (HMI) which could be increase the number of
output voltage level. Total Harmonic Distortion (THD) is one of the
most important requirements concerning performance indices.
Because of many numbers output levels of HMI, it had numerous
unknown variables of eliminate undesired individual harmonic and
THD nonlinear equations set. Optimized harmonic stepped waveform
(OHSW) is solving switching angles conventional method, but most
complicated for solving as added level. The artificial intelligent
techniques are deliberation to solve this problem. This paper presents
the Particle Swarm Optimization (PSO) technique for solving
switching angles to get minimum THD and eliminate undesired
individual harmonics of 15-levels hybrid multilevel inverters.
Consequently it had many variables and could eliminate numerous
harmonics. Both advantages including high level of inverter and
Particle Swarm Optimization (PSO) are used as powerful tools for
harmonics elimination.
Abstract: Inorganic nanoparticles filled polymer composites
have extended their multiple functionalities to various applications,
including mechanical reinforcement, gas barrier, dimensional
stability, heat distortion temperature, flame-retardant, and thermal
conductivity. Sodium stearate-modified calcium carbonate (CaCO3)
nanoparticles were prepared using surface modification method. The
results showed that sodium stearate attached to the surface of CaCO3
nanoparticles with the chemical bond. The effect of modified CaCO3
nanoparticles on thermal properties of polypropylene (PP) was
studied by means of differential scanning calorimetry (DSC) and
Thermogravimetric analysis (TGA). It was found that CaCO3
significantly affected the crystallization temperature and
crystallization degree of PP. Effect of the modified CaCO3 content on
mechanical properties of PP/CaCO3 nanocomposites was also
studied. The results showed that the modified CaCO3 can effectively
improve the mechanical properties of PP. In comparison with PP, the
impact strength of PP/CaCO3 nanocomposites increased by about
65% and the hardness increased by about 5%.
Abstract: In this paper, the dynamics of a system of two van der Pol oscillators with delayed position and velocity is studied. We provide an approximate solution for this system using parameterexpansion method. Also, we obtain approximate values for frequencies of the system. The parameter-expansion method is more efficient than the perturbation method for this system because the method is independent of perturbation parameter assumption.
Abstract: Let X be a connected space, X be a space, let p : X -→ X be a continuous map and let (X, p) be a covering space of X. In the first section we give some preliminaries from covering spaces and their automorphism groups. In the second section we derive some algebraic properties of both universal and regular covering spaces (X, p) of X and also their automorphism groups A(X, p).
Abstract: This paper analytically investigates the 3D flow
pattern at the confluences of two rectangular channels having 900
angles using Navier-Stokes equations based on Reynolds Stress
Turbulence Model (RSM). The equations are solved by the Finite-
Volume Method (FVM) and the flow is analyzed in terms of steadystate
(single-phased) conditions. The Shumate experimental findings
were used to test the validity of data. Comparison of the simulation
model with the experimental ones indicated a close proximity
between the flow patterns of the two sets. Effects of the discharge
ratio on separation zone dimensions created in the main-channel
downstream of the confluence indicated an inverse relation, where a
decrease in discharge ratio, will entail an increase in the length and
width of the separation zone. The study also found the model as a
powerful analytical tool in the feasibility study of hydraulic
engineering projects.
Abstract: The highly nonlinear characteristics of drying
processes have prompted researchers to seek new nonlinear control
solutions. However, the relation between the implementation
complexity, on-line processing complexity, reliability control
structure and controller-s performance is not well established. The
present paper proposes high performance nonlinear fuzzy controllers
for a real-time operation of a drying machine, being developed under
a consistent match between those issues. A PCI-6025E data
acquisition device from National Instruments® was used, and the
control system was fully designed with MATLAB® / SIMULINK
language. Drying parameters, namely relative humidity and
temperature, were controlled through MIMOs Hybrid Bang-bang+PI
(BPI) and Four-dimensional Fuzzy Logic (FLC) real-time-based
controllers to perform drying tests on biological materials. The
performance of the drying strategies was compared through several
criteria, which are reported without controllers- retuning. Controllers-
performance analysis has showed much better performance of FLC
than BPI controller. The absolute errors were lower than 8,85 % for
Fuzzy Logic Controller, about three times lower than the
experimental results with BPI control.
Abstract: Intermetallic Ni3Al – based alloys belong to a group
of advanced materials characterized by good chemical and physical
properties (such as structural stability, corrosion resistance) which
offer advenced technological applications. The paper presents the
study of catalytic properties of Ni3Al foils (thickness approximately
50 &m) in the methanol and hexane decomposition. The egzamined
material posses microcrystalline structure without any additional
catalysts on the surface. The better catalytic activity of Ni3Al foils
with respect to quartz plates in both methanol and hexane
decomposition was confirmed. On thin Ni3Al foils the methanol
conversion reaches approximately 100% above 480 oC while the
hexane conversion reaches approximately 100% (98,5%) at 500 oC.
Deposit formed during the methanol decomposition is built up of
carbon nanofibers decorated with metal-like nanoparticles.
Abstract: To illustrate diversity of methods used to extract relevant (where the concept of relevance can be differently defined for different applications) visual data, the paper discusses three groups of such methods. They have been selected from a range of alternatives to highlight how hardware and software tools can be complementarily used in order to achieve various functionalities in case of different specifications of “relevant data". First, principles of gated imaging are presented (where relevance is determined by the range). The second methodology is intended for intelligent intrusion detection, while the last one is used for content-based image matching and retrieval. All methods have been developed within projects supervised by the author.
Abstract: One major issue that is regularly cited as a block to
the widespread use of online assessments in eLearning, is that of the
authentication of the student and the level of confidence that an
assessor can have that the assessment was actually completed by that
student. Currently, this issue is either ignored, in which case
confidence in the assessment and any ensuing qualification is
damaged, or else assessments are conducted at central, controlled
locations at specified times, losing the benefits of the distributed
nature of the learning programme. Particularly as we move towards
constructivist models of learning, with intentions towards achieving
heutagogic learning environments, the benefits of a properly
managed online assessment system are clear. Here we discuss some
of the approaches that could be adopted to address these issues,
looking at the use of existing security and biometric techniques,
combined with some novel behavioural elements. These approaches
offer the opportunity to validate the student on accessing an
assessment, on submission, and also during the actual production of
the assessment. These techniques are currently under development in
the DECADE project, and future work will evaluate and report their
use..
Abstract: In this study, a synthetic pathway was created by
assembling genes from Clostridium butyricum and Escherichia coli
in different combinations. Among the genes were dhaB1 and dhaB2
from C. butyricum VPI1718 coding for glycerol dehydratase (GDHt)
and its activator (GDHtAc), respectively, involved in the conversion
of glycerol to 3-hydroxypropionaldehyde (3-HPA). The yqhD gene
from E.coli BL21 was also included which codes for an NADPHdependent
1,3-propanediol oxidoreductase isoenzyme (PDORI)
reducing 3-HPA to 1,3-propanediol (1,3-PD). Molecular modeling
analysis indicated that the conformation of fusion protein of YQHD
and DHAB1 was favorable for direct molecular channeling of the
intermediate 3-HPA. According to the simulation results, the yqhD
and dhaB1 gene were assembled in the upstream of dhaB2 to express
a fusion protein, yielding the recombinant strain E. coliBL21
(DE3)//pET22b+::yqhD-dhaB1_dhaB2 (strain BP41Y3). Strain
BP41Y3 gave 10-fold higher 1,3-PD concentration than E. coliBL21
(DE3)//pET22b+::yqhD-dhaB1_dhaB2 (strain BP31Y2) expressing
the recombinant enzymes simultaneously but in a non-fusion mode.
This is the first report using a gene fusion approach to enhance the
biological conversion of glycerol to the value added compound 1,3-
PD.
Abstract: We present a method for fast volume rendering using
graphics hardware (GPU). To our knowledge, it is the first implementation
on the GPU. Based on the Shear-Warp algorithm, our
GPU-based method provides real-time frame rates and outperforms
the CPU-based implementation. When the number of slices is not
sufficient, we add in-between slices computed by interpolation. This
improves then the quality of the rendered images. We have also
implemented the ray marching algorithm on the GPU. The results
generated by the three algorithms (CPU-based and GPU-based Shear-
Warp, GPU-based Ray Marching) for two test models has proved that
the ray marching algorithm outperforms the shear-warp methods in
terms of speed up and image quality.
Abstract: Nanophotocatalysts such as titanium (TiO2), zinc (ZnO), and iron (Fe2O3) oxides can be used in organic pollutants oxidation, and in many other applications. But among the challenges for technological application (scale-up) of the nanotechnology scientific developments two aspects are still little explored: research on environmental risk of the nanomaterials preparation methods, and the study of nanomaterials properties and/or performance variability. The environmental analysis was performed for six different methods of ZnO nanoparticles synthesis, and showed that it is possible to identify the more environmentally compatible process even at laboratory scale research. The obtained ZnO nanoparticles were tested as photocatalysts, and increased the degradation rate of the Rhodamine B dye up to 30 times.
Abstract: “Web of Trust" is one of the recognized goals for
Web 2.0. It aims to make it possible for the people to take
responsibility for what they publish on the web, including
organizations, businesses and individual users. These objectives,
among others, drive most of the technologies and protocols recently
standardized by the governing bodies. One of the great advantages of
Web infrastructure is decentralization of publication. The primary
motivation behind Web 2.0 is to assist the people to add contents for
Collective Intelligence (CI) while providing mechanisms to link
content with people for evaluations and accountability of
information. Such structure of contents will interconnect users and
contents so that users can use contents to find participants and vice
versa. This paper proposes conceptual information storage and
linking model, based on decentralized information structure, that
links contents and people together. The model uses FOAF, Atom,
RDF and RDFS and can be used as a blueprint to develop Web 2.0
applications for any e-domain. However, primary target for this
paper is online trust evaluation domain. The proposed model targets
to assist the individuals to establish “Web of Trust" in online trust
domain.
Abstract: Participation in sporting activities can lead to injury.
Sport injuries have been widely studied in many sports including the
more extreme categories of aquatic board sports. Kitesurfing is a
relatively new water surface action sport, and has not yet been
widely studied in terms of injuries and stress on the body. The aim of
this study was to get information about which injuries that are most
common among kitesurfing participants, where they occur, and their
causes. Injuries were studied using an international open web
questionnaire (n=206).
The results showed that many respondents reported injuries, in
total 251 injuries to knee (24%), ankle (17%), trunk (16%) and
shoulders (10%), often sustained while doing jumps and tricks
(40%). Among the reported injuries were joint injuries (n=101),
muscle/tendon damages (n=47), wounds and cuts (n=36) and bone
fractures (n=28). Also environmental factors and equipment can
influence the risk of injury, or the extent of injury in a hazardous
situation. Conclusively, the information from this retrospective study
supports earlier studies in terms of prevalence and site of injuries.
Suggestively, this information should be used for to build a
foundation of knowledge about the sport for development of
applications for physical training and product development.
Abstract: The aim of this article is to explain how features of attacks could be extracted from the packets. It also explains how vectors could be built and then applied to the input of any analysis stage. For analyzing, the work deploys the Feedforward-Back propagation neural network to act as misuse intrusion detection system. It uses ten types if attacks as example for training and testing the neural network. It explains how the packets are analyzed to extract features. The work shows how selecting the right features, building correct vectors and how correct identification of the training methods with nodes- number in hidden layer of any neural network affecting the accuracy of system. In addition, the work shows how to get values of optimal weights and use them to initialize the Artificial Neural Network.
Abstract: The performance and complexity of QoS routing depends on the complex interaction between a large set of parameters. This paper investigated the scaling properties of source-directed link-state routing in large core networks. The simulation results show that the routing algorithm, network topology, and link cost function each have a significant impact on the probability of successfully routing new connections. The experiments confirm and extend the findings of other studies, and also lend new insight designing efficient quality-of-service routing policies in large networks.
Abstract: The research object was wheat bread. Experiments
were carried out at the Faculty of Food Technology of the Latvia
University of Agriculture. An active packaging in combination with
modified atmosphere (MAP, CO2 60% and N2 40%) was examined
and compared with traditional packaging in air ambiance. Polymer
Multibarrier 60, PP and OPP bags were used. Influence of iron based
oxygen absorber in sachets of 100 cc obtained from Mitsubishi Gas
Chemical Europe Ageless® was tested on the quality during the shelf
of wheat bread. Samples of 40±4 g were packaged in polymer
pouches (110 mm x 120 mm), hermetically sealed by MULTIVAC
C300 vacuum chamber machine, and stored in room temperature
+21.0±0.5 °C. The physiochemical properties – weight losses,
moisture content, hardness, pH, colour, changes of atmosphere
content (CO2 and O2) in headspace of packs, and microbial
conditions were analysed before packaging and in the 7th, 14th, 21st
and 28th days of storage.
Abstract: The aim of the present work is to study the effect of annealing on the vibration damping capacity of high-chromium (16%) ferromagnetic steel. The alloys were prepared from raw materials of 99.9% purity melted in a high frequency induction furnace under high vacuum. The samples were heat-treated in vacuum at various temperatures (800 to 1200ºC) for 1 hour followed by slow cooling (120ºC/h). The inverted torsional pendulum method was used to evaluate the vibration damping capacity. The results indicated that the vibration damping capacity of the alloys is influenced by annealing and there exists a critical annealing temperature after 1000ºC. The damping capacity increases quickly below the critical temperature since the magnetic domains move more easily.