Abstract: Environmental impacts of six 3D printers using
various materials were compared to determine if material choice
drove sustainability, or if other factors such as machine type, machine
size, or machine utilization dominate. Cradle-to-grave life-cycle
assessments were performed, comparing a commercial-scale FDM
machine printing in ABS plastic, a desktop FDM machine printing in
ABS, a desktop FDM machine printing in PET and PLA plastics, a
polyjet machine printing in its proprietary polymer, an SLA machine
printing in its polymer, and an inkjet machine hacked to print in salt
and dextrose. All scenarios were scored using ReCiPe Endpoint H
methodology to combine multiple impact categories, comparing
environmental impacts per part made for several scenarios per
machine. Results showed that most printers’ ecological impacts were
dominated by electricity use, not materials, and the changes in
electricity use due to different plastics was not significant compared
to variation from one machine to another. Variation in machine idle
time determined impacts per part most strongly. However, material
impacts were quite important for the inkjet printer hacked to print in
salt: In its optimal scenario, it had up to 1/38th the impacts coreper
part as the worst-performing machine in the same scenario. If salt
parts were infused with epoxy to make them more physically robust,
then much of this advantage disappeared, and material impacts
actually dominated or equaled electricity use. Future studies should
also measure DMLS and SLS processes / materials.
Abstract: Measurements and quantitative analysis of kinematic
parameters of human hand movements have an important role in
different areas such as hand function rehabilitation, modeling of
multi-digits robotic hands, and the development of machine-man
interfaces. In this paper the assessment and evaluation of the reachto-
grasp movement by using computerized and robot-assisted method
is described. Experiment involved the measurements of hand
positions of seven healthy subjects during grasping three objects of
different shapes and sizes. Results showed that three dominant phases
of reach-to-grasp movements could be clearly identified.
Abstract: It is difficult to study the effect of various variables on
cycle fitting through actual experiment. To overcome such difficulty,
the forward dynamics of a musculoskeletal model was applied to cycle
fitting in this study. The measured EMG data weres compared with the
muscle activities of the musculoskeletal model through forward
dynamics. EMG data were measured from five cyclists who do not
have musculoskeletal diseases during three minutes pedaling with a
constant load (150 W) and cadence (90 RPM). The muscles used for
the analysis were the Vastus Lateralis (VL), Tibialis Anterior (TA),
Bicep Femoris (BF), and Gastrocnemius Medial (GM). Person’s
correlation coefficients of the muscle activity patterns, the peak timing
of the maximum muscle activities, and the total muscle activities were
calculated and compared. BIKE3D model of AnyBody (Anybodytech,
Denmark) was used for the musculoskeletal model simulation. The
comparisons of the actual experiments with the simulation results
showed significant correlations in the muscle activity patterns (VL:
0.789, TA: 0.503, BF: 0.468, GM: 0.670). The peak timings of the
maximum muscle activities were distributed at particular phases. The
total muscle activities were compared with the normalized muscle
activities, and the comparison showed about 10% difference in the VL
(+10%), TA (+9.7%), and BF (+10%), excluding the GM (+29.4%).
Thus, it can be concluded that muscle activities of model &
experiment showed similar results. The results of this study indicated
that it was possible to apply the simulation of further improved
musculoskeletal model to cycle fitting.
Abstract: Modular structural systems are constructed using a
method that they are assembled with prefabricated unit modular
frames on-site. This provides a benefit that can significantly reduce
building construction time. The structural design is usually carried out
under the assumption that their load-carrying mechanism is similar to
that of traditional steel moment-resisting systems. However, both
systems are different in terms of beam-column connection details
which may strongly influence the lateral structural behavior. Specially,
the presence of access holes in a beam-column joint of a unit modular
frame could cause undesirable failure during strong earthquakes.
Therefore, this study carried out finite element analyses (FEMs) of
unit modular frames to investigate the cyclic behavior of beam-column
joints with the access holes. Analysis results show that the unit
modular frames present stable cyclic response with large deformation
capacities and their joints are classified into semi-rigid connections
even if there are access holes.
Abstract: This paper describes a novel application of Fiber
Braggs Grating (FBG) sensors in the assessment of human postural
stability and balance on an unstable platform. In this work, FBG
sensor Stability Analyzing Device (FBGSAD) is developed for
measurement of plantar strain to assess the postural stability of
subjects on unstable platforms during different stances in eyes open
and eyes closed conditions on a rocker board. The studies are
validated by comparing the Centre of Gravity (CG) variations
measured on the lumbar vertebra of subjects using a commercial
accelerometer. The results obtained from the developed FBGSAD
depict qualitative similarities with the data recorded by commercial
accelerometer. The advantage of the FBGSAD is that it measures
simultaneously plantar strain distribution and postural stability of the
subject along with its inherent benefits like non-requirement of
energizing voltage to the sensor, electromagnetic immunity and
simple design which suits its applicability in biomechanical
applications. The developed FBGSAD can serve as a tool/yardstick to
mitigate space motion sickness, identify individuals who are
susceptible to falls and to qualify subjects for balance and stability,
which are important factors in the selection of certain unique
professionals such as aircraft pilots, astronauts, cosmonauts etc.
Abstract: We have developed a new computer program in
Fortran 90, in order to obtain numerical solutions of a system
of Relativistic Magnetohydrodynamics partial differential equations
with predetermined gravitation (GRMHD), capable of simulating
the formation of relativistic jets from the accretion disk of matter
up to his ejection. Initially we carried out a study on numerical
methods of unidimensional Finite Volume, namely Lax-Friedrichs,
Lax-Wendroff, Nessyahu-Tadmor method and Godunov methods
dependent on Riemann problems, applied to equations Euler in
order to verify their main features and make comparisons among
those methods. It was then implemented the method of Finite
Volume Centered of Nessyahu-Tadmor, a numerical schemes that
has a formulation free and without dimensional separation of
Riemann problem solvers, even in two or more spatial dimensions,
at this point, already applied in equations GRMHD. Finally, the
Nessyahu-Tadmor method was possible to obtain stable numerical
solutions - without spurious oscillations or excessive dissipation -
from the magnetized accretion disk process in rotation with respect
to a central black hole (BH) Schwarzschild and immersed in a
magnetosphere, for the ejection of matter in the form of jet over a
distance of fourteen times the radius of the BH, a record in terms
of astrophysical simulation of this kind. Also in our simulations,
we managed to get substructures jets. A great advantage obtained
was that, with the our code, we got simulate GRMHD equations in
a simple personal computer.
Abstract: In previous study, technique to estimate a self-location by using a lunar image is proposed.We consider the improvement of the conventional method in consideration of FPGA implementationin this paper. Specifically, we introduce Artificial Bee Colony algorithm for reduction of search time.In addition, we use fixed point arithmetic to enable high-speed operation on FPGA.
Abstract: The most important component affecting the
efficiency of photovoltaic power systems are solar panels. In other
words, efficiency of these systems are significantly affected due to
the being low efficiency of solar panel. Thus, solar panels should be
operated under maximum power point conditions through a power
converter. In this study, design of boost converter has been carried
out with maximum power point tracking (MPPT) algorithm which is
incremental conductance (Inc-Cond). By using this algorithm,
importance of power converter in MPPT hardware design, impacts of
MPPT operation have been shown. It is worth noting that initial
operation point is the main criteria for determining the MPPT
performance. In addition, it is shown that if value of load resistance is
lower than critical value, failure operation is realized. For these
analyzes, direct duty control is used for simplifying the control.
Abstract: A feeding experiment was conducted to determine the
optimum dietary protein and lipid levels for juvenile fancy carp. Eight
experimental diets were formulated to contain four protein levels (200,
300, 400 and 500 g kg-1) with two lipid levels (70 and 140 g kg-1).
Triplicate groups of fish (initial weight, 12.1±0.2 g fish-1) were
hand-fed the diets to apparent satiation for 8 weeks. Fish growth
performance, feed utilization and feed intake were significantly
(P0.05). Weight gain and feed efficiency ratio tended to
increase as dietary protein level increased up to 400 and 500 g kg-1,
respectively. Daily feed intake of fish decreased with increasing
dietary protein level and that of fish fed diet contained 500 g kg-1
protein was significantly lower than other fish groups. The protein
efficiency ratio of fish fed 400 and 500 g kg-1 protein was lower than
that of fish fed 200 and 300 g kg-1 protein. Moisture, crude protein and
crude lipid contents of muscle and liver were significantly affected by
dietary protein, but not by dietary lipid level (P>0.05). The increase in
dietary lipid level resulted in an increase in linoleic acid in liver and
muscle paralleled with a decrease in n-3 highly unsaturated fatty acids
content in muscle of fish. In considering these results, it was concluded
that the diet containing 400 g kg-1 protein with 70 g kg-1 lipid level is
optimal for growth and efficient feed utilization of juvenile fancy carp.
Abstract: Nowadays, the successful implementation of ICTs is
vital for almost any kind of organization. Good governance and ICT
management are essential for delivering value, managing
technological risks, managing resources and performance
measurement. In addition, outsourcing is a strategic IT service
solution which complements IT services provided internally in
organizations. This paper proposes the measurement tools of a new
holistic maturity model based on standards ISO/IEC 20000 and
ISO/IEC 38500, and the frameworks and best practices of ITIL and
COBIT, with a specific focus on IT outsourcing. These measurement
tools allow independent validation and practical application in the
field of higher education, using a questionnaire, metrics tables, and
continuous improvement plan tables as part of the measurement
process. Guidelines and standards are proposed in the model for
facilitating adaptation to universities and achieving excellence in the
outsourcing of IT services.
Abstract: Since large part of electricity is generated by using
fossil based resources, energy is an important agenda for countries. In
this context, renewable energy sources are alternative to conventional
sources due to the depletion of fossil resources, increasing awareness
of climate change and global warming concerns. Solar, wind and
hydropower energy are the main renewable energy sources. Among
of them, since installed capacity of wind power has increased
approximately eight times between 2008 - November of 2014, wind
energy is a promising source for Turkey. Furthermore, signing of
Kyoto Protocol can be accepted as a milestone for Turkey's energy
policy. Turkish Government has announced Vision 2023 (energy
targets by 2023) in 2010-2014 Strategic Plan prepared by Ministry of
Energy and Natural Resources (MENR). Energy targets in this plan
can be summarized as follows: Share of renewable energy sources in
electricity generation is 30% of total electricity generation by 2023.
Installed capacity of wind energy will be 20 GW by 2023. Other
renewable energy sources such as solar, hydropower and geothermal
are encouraged with new incentive mechanisms. Dependence on
foreign energy is reduced for sustainability and energy security. On
the other hand, since Turkey is surrounded by three coastal areas,
wind energy potential is convenient for wind power application. As
of November of 2014, total installed capacity of wind power plants is
3.51 GW and a lot of wind power plants are under construction with
capacity 1.16 GW. Turkish government also encourages the locally
manufactured equipments. In this context, one of the projects funded
by private sector, universities and TUBİTAK names as MILRES is
an important project aimed to promote the use wind energy in
electricity generation. Within this project, wind turbine with 500 kW
power has been produced and will be installed at the beginning of the
2015. After that, by using the experience obtained from the first
phase of the project, a wind turbine with 2.5 MW power will be
manufactured in an industrial scale.
Abstract: Due to water shortage, application of saline water for
irrigation is an urgent in agriculture. In this study the effect of
calcium and potassium application as additive in saline root media for
reduce salinity adverse effects was investigated on tomato growth in
a hydroponic system with unequal distribution of salts in the root
media, which was divided in to two equal parts containing full
Johnson nutrient solution and 40 mMNaCl solution, alone or in
combination with KCl (6 mM), CaCl2 (4 mM), K+Ca (3+2 mM) or
half-strength Johnson nutrient solution. The root splits were
exchanged every 7 days. Results showed that addition of calcium,
calcium-potassium and nutrition elements equivalent to half the
concentration of Johnson formula to the saline-half of culture media
minimized the reduction in plant growth caused by NaCl, although
addition of potassium to culture media wasn’t effective. The greatest
concentration of sodium was observed at the shoot of treatments
which had smallest growth. According to the results of this study, in
case of dynamic and non-uniform distribution of salts in the root
media, by addition of additive to the saline solution, it would be
possible to use of saline water with no significant growth reduction.
Abstract: Starting in 2020, an EU-wide CO2-limitation of
95 g/km is scheduled for the average of an OEMs passenger car fleet.
Taking that into consideration additional improvement measures of
the Diesel cycle are necessary in order to reduce fuel consumption
and emissions while boosting, or at the least, keeping performance
values at the same time.
The present article deals with the possibilities of an optimized
air/water charge air cooler, also called iCAC (indirect Charge Air
Cooler) for a Diesel passenger car amongst extreme-boundary
conditions. In this context, the precise objective was to show the
impact of improved intercooling with reference to the engine working
process (fuel consumption and NOx-emissions). Several extremeboundaries
- e.g. varying ambient temperatures or mountainous
routes - that will become very important in the near future regarding
RDE (Real Driving emissions) were subject of the investigation.
With the introduction of RDE in 2017 (EU6c measure), the
controversial NEDC (New European Driving Cycle) will belong to
the past and the OEMs will have to avoid harmful emissions in any
conceivable real life situation.
This is certainly going to lead to optimization-measurements at the
powertrain, which again is going to make the implementation of
iCACs, presently solely used for the premium class, more and more
attractive for compact class cars. The investigations showed a benefit
in FC between 1 and 3% for the iCAC in real world conditions.
Abstract: Given the importance of ports as links in the global
supply chains and because they are key elements to induce
competitiveness in their hinterlands, the number of studies devoted to
port governance, management and operations has increased in the last
decades. Some of these studies address the port governance model as
an element to improve coordination among the actors of the portlogistics
chain and to generate a better port performance. In this
context, the present study analyzes the governance of Port of Santos
through individual interviews with port managers, based on a
conceptual model that considers the key dimensions associated with
port governance. The results reinforce the usefulness of the applied
model and highlight some existing improvement opportunities in the
port studied.
Abstract: Currently, thorium fuel has been especially noticed
because of its proliferation resistance than long half-life alpha emitter
minor actinides, breeding capability in fast and thermal neutron flux
and mono-isotopic naturally abundant. In recent years, efficiency of
minor actinide burning up in PWRs has been investigated. Hence, a
minor actinide-contained thorium based fuel matrix can confront both
proliferation resistance and nuclear waste depletion aims. In the
present work, minor actinide depletion rate in a CANDU-type nuclear
core modeled using MCNP code has been investigated. The obtained
effects of minor actinide load as mixture of thorium fuel matrix on
the core neutronics has been studied with comparing presence and
non-presence of minor actinide component in the fuel matrix.
Depletion rate of minor actinides in the MA-contained fuel has been
calculated using different power loads. According to the obtained
computational data, minor actinide loading in the modeled core
results in more negative reactivity coefficients. The MA-contained
fuel achieves less radial peaking factor in the modeled core. The
obtained computational results showed 140 kg of 464 kg initial load
of minor actinide has been depleted in during a 6-year burn up in 10
MW power.
Abstract: Particles exhausted from cars have adverse impacts on
human health. The study developed a three-dimensional particle
dispersion numerical model including particle coagulation to simulate
the particle concentration distribution under idling conditions in a
residential underground garage. The simulation results demonstrate
that particle disperses much faster in the vertical direction than that in
horizontal direction. The enhancement of particle dispersion in the
vertical direction due to the increase of cars with engine running is
much stronger than that in the car exhaust direction. Particle dispersion
from each pair of adjacent cars has little influence on each other in the
study. Average particle concentration after 120 seconds exhaust is
1.8-4.5 times higher than the initial total particles at ambient
environment. Particle pollution in the residential underground garage
is severe.
Abstract: This paper presents a new structure of microstrip band
pass filter (BPF) based on coupled stepped impedance resonators.
Each filter consists of two coupled stepped impedance resonators
connected to microstrip feed lines. The coupled junction is utilized to
connect the two BPFs to the antenna. This two band pass filters are
designed and simulated to operate for the digital communication
system (DCS) and Industrial Scientific and Medical (ISM) bands at
1.8 GHz and 2.45 GHz respectively. The proposed circuit presents
good performances with an insertion loss lower than 2.3 dB and
isolation between the two channels greater than 21 dB. The prototype
of the optimized diplexer have been investigated numerically by
using ADS Agilent and verified with CST microwave software.
Abstract: The thermal conductivity of a fluid can be
significantly enhanced by dispersing nano-sized particles in it, and
the resultant fluid is termed as "nanofluid". A theoretical model for
estimating the thermal conductivity of a nanofluid has been proposed
here. It is based on the mechanism that evenly dispersed
nanoparticles within a nanofluid undergo Brownian motion in course
of which the nanoparticles repeatedly collide with the heat source.
During each collision a rapid heat transfer occurs owing to the solidsolid
contact. Molecular dynamics (MD) simulation of the collision
of nanoparticles with the heat source has shown that there is a pulselike
pick up of heat by the nanoparticles within 20-100 ps, the extent
of which depends not only on thermal conductivity of the
nanoparticles, but also on the elastic and other physical properties of
the nanoparticle. After the collision the nanoparticles undergo
Brownian motion in the base fluid and release the excess heat to the
surrounding base fluid within 2-10 ms. The Brownian motion and
associated temperature variation of the nanoparticles have been
modeled by stochastic analysis. Repeated occurrence of these events
by the suspended nanoparticles significantly contributes to the
characteristic thermal conductivity of the nanofluids, which has been
estimated by the present model for a ethylene glycol based nanofluid
containing Cu-nanoparticles of size ranging from 8 to 20 nm, with
Gaussian size distribution. The prediction of the present model has
shown a reasonable agreement with the experimental data available
in literature.
Abstract: Artificial Neural Network (ANN) can be trained using
back propagation (BP). It is the most widely used algorithm for
supervised learning with multi-layered feed-forward networks.
Efficient learning by the BP algorithm is required for many practical
applications. The BP algorithm calculates the weight changes of
artificial neural networks, and a common approach is to use a twoterm
algorithm consisting of a learning rate (LR) and a momentum
factor (MF). The major drawbacks of the two-term BP learning
algorithm are the problems of local minima and slow convergence
speeds, which limit the scope for real-time applications. Recently the
addition of an extra term, called a proportional factor (PF), to the
two-term BP algorithm was proposed. The third increases the speed
of the BP algorithm. However, the PF term also reduces the
convergence of the BP algorithm, and criteria for evaluating
convergence are required to facilitate the application of the three
terms BP algorithm. Although these two seem to be closely related,
as described later, we summarize various improvements to overcome
the drawbacks. Here we compare the different methods of
convergence of the new three-term BP algorithm.
Abstract: This study examines the credibility of the signaling as
explanation for IPO initial underpricing. Findings reveal the initial
underpricing and the long-term underperformance of IPOs in Taiwan.
However, we only find weak support for signaling as explanation of
IPO underpricing.