Abstract: The ventilated façade has great advantages when
compared to traditional façades as it reduces the air conditioning
thermal loads due to the stack effect induced by solar radiation in the
air chamber. Optimizing energy consumption by using a ventilated
façade can be used not only in newly built buildings but also it can be
implemented in existing buildings, opening the field of
implementation to energy building retrofitting works. In this sense, the following three prototypes of façade where
designed, built and further analyzed in this research: non-ventilated
façade (NVF); slightly ventilated façade (SLVF) and strongly
ventilated façade (STVF). The construction characteristics of the
three facades are based on the Spanish regulation of building
construction “Technical Building Code”. The façades have been
monitored by type-k thermocouples in a representative day of the
summer season in Madrid (Spain). Moreover, an analysis of variance
(ANOVA) with repeated measures, studying the thermal lag in the
ventilated and no-ventilated façades has been designed. Results show that STVF façade presents higher levels of thermal
inertia as the thermal lag reduces up to 17% (daily mean) compared
to the non-ventilated façade. In addition, the statistical analysis
proves that an increase of the ventilation holes size in STVF façades
can improve the thermal lag significantly (p >0.05) when compared
to the SLVF façade.
Abstract: Main objective of this paper is to establish a link
between inertial forces of the bearings used in construction of wind
power plant and its behavior. Using bearings with lower inertial
forces has the immediate effect of decreasing inertia rotor system,
with significant results in increased energy efficiency, due to
decreased friction forces between rollers and raceways. The F.E.M.
analysis shows the appearance of uniform contact stress at the ends of
the rollers, demonstrated the necessity of production of low mass
bearings. Favorable results are expected in the economic field, by
reducing material consumption and by increasing the durability of
bearings. Using low mass bearings with hollow rollers instead of
solid rollers has an impact on working temperature, on vibrations and
noise which decrease. Implementation of types of hollow rollers of
cylindrical tubular type, instead of expensive rollers with logarithmic
profile, will bring significant inertial forces decrease with large
benefits in behavior of wind power plant.
Abstract: Method of combined teaching laws of classical
mechanics and hydrostatics in non-inertial reference frames for
undergraduate students is proposed. Pressure distribution in a liquid
(or gas) moving with acceleration is considered. Combined effect of
hydrostatic force and force of inertia on a body immersed in a liquid
can lead to paradoxical results, in a motion of pendulum in particular.
The body motion under Stokes force influence and forces in rotating
reference frames are investigated as well. Problems and difficulties in
student perceptions are analyzed.
Abstract: This paper presents the design process of a high
performance 3-phase 3.7 kW 2-pole line start permanent magnet
synchronous motor for pumping system. A method was proposed to
study the starting torque characteristics considering line start with
high inertia load. A d-q model including cage was built to study the
synchronization capability. Time-stepping finite element method
analysis was utilized to accurately predict the dynamic and transient
performance, efficiency, starting current, speed curve and etc.
Considering the load torque of pumps during starting stage, the rotor
bar was designed with minimum demagnetization of permanent
magnet caused by huge starting current.
Abstract: Nine Degrees of Freedom (9 DOF) systems are
already in development in many areas. In this paper, an integrated
pressure sensor is proposed that will make use of an already existing
monolithic 9 DOF inertial MEMS platform. Capacitive pressure
sensors can suffer from limited sensitivity for a given size of
membrane. This novel pressure sensor design increases the sensitivity
by over 5 times compared to a traditional array of square diaphragms
while still fitting within a 2 mm x 2 mm chip and maintaining a fixed
static capacitance. The improved design uses one large diaphragm
supported by pillars with fixed electrodes placed above the areas of
maximum deflection. The design optimization increases the
sensitivity from 0.22 fF/kPa to 1.16 fF/kPa. Temperature sensitivity
was also examined through simulation.
Abstract: Contemporary theories of sustainability, concerning
the natural and built environment, have recently introduced an
environmental attitude towards the architectural design that, in turn,
affects the practice of conservation and reuse of the existing building
stock. This paper presents an environmentally friendly approach
towards the conservation of vernacular architecture and it is based on
the results of a research program which involved the investigation of
sustainable design elements of traditional buildings in Cyprus. The
research in question showed that Cypriot vernacular architecture gave
more emphasis on cooling rather than heating strategies. Another
notable finding of the investigation was the great importance given to
courtyards as they enhance considerably, and in various ways, the
microclimatic conditions of the immediate environment with
favorable results throughout the year. Moreover, it was shown that
the reduction in temperature fluctuation observed in the closed and
semi-open spaces, compared to the respective temperature fluctuation
of the external environment -due to the thermal inertia of the building
envelope- helps towards the achievement of more comfortable living
conditions within traditional dwellings. This paper concludes with a
proposal of a sustainable approach towards the conservation of the
existing environment and the introduction of new environmental
criteria for the conservation of traditional buildings, beyond the
aesthetic, morphological and structural ones that are generally
applied.
Abstract: Surf is an increasingly popular sport and its performance evaluation is often qualitative. This work aims at using a smartphone to collect and analyze the GPS and inertial sensors data in order to obtain quantitative metrics of the surfing performance. Two approaches are compared for detection of wave rides, computing the number of waves rode in a surfing session, the starting time of each wave and its duration. The first approach is based on computing the velocity from the Global Positioning System (GPS) signal and finding the velocity thresholds that allow identifying the start and end of each wave ride. The second approach adds information from the Inertial Measurement Unit (IMU) of the smartphone, to the velocity thresholds obtained from the GPS unit, to determine the start and end of each wave ride. The two methods were evaluated using GPS and IMU data from two surfing sessions and validated with similar metrics extracted from video data collected from the beach. The second method, combining GPS and IMU data, was found to be more accurate in determining the number of waves, start time and duration. This paper shows that it is feasible to use smartphones for quantification of performance metrics during surfing. In particular, detection of the waves rode and their duration can be accurately determined using the smartphone GPS and IMU.
Abstract: Micro-electromechanical system (MEMS)
accelerometers and gyroscopes are suitable for the inertial navigation
system (INS) of many applications due to low price, small
dimensions and light weight. The main disadvantage in a comparison
with classic sensors is a worse long term stability. The estimation
accuracy is mostly affected by the time-dependent growth of inertial
sensor errors, especially the stochastic errors. In order to eliminate
negative effects of these random errors, they must be accurately
modeled. In this paper, the Allan variance technique will be used in
modeling the stochastic errors of the inertial sensors. By performing
a simple operation on the entire length of data, a characteristic curve
is obtained whose inspection provides a systematic characterization
of various random errors contained in the inertial-sensor output data.
Abstract: Quality of Service (QoS) attributes as part of the
service description is an important factor for service attribute. It is not
easy to exactly quantify the weight of each QoS conditions since
human judgments based on their preference causes vagueness. As
web services selection requires optimization, evolutionary computing
based on heuristics to select an optimal solution is adopted. In this
work, the evolutionary computing technique Particle Swarm
Optimization (PSO) is used for selecting a suitable web services
based on the user’s weightage of each QoS values by optimizing the
QoS weight vector and thereby finding the best weight vectors for
best services that is being selected. Finally the results are compared
and analyzed using static inertia weight and deterministic inertia
weight of PSO.
Abstract: The article deals with the tool in Matlab GUI form
that is designed to analyse a mechatronic system sensitivity and
tolerance. In the analysed mechatronic system, a torque is transferred
from the drive to the load through a coupling containing flexible
elements. Different methods of control system design are used. The
classic form of the feedback control is proposed using Naslin method,
modulus optimum criterion and inverse dynamics method. The
cascade form of the control is proposed based on combination of
modulus optimum criterion and symmetric optimum criterion. The
sensitivity is analysed on the basis of absolute and relative sensitivity
of system function to the change of chosen parameter value of the
mechatronic system, as well as the control subsystem. The tolerance
is analysed in the form of determining the range of allowed relative
changes of selected system parameters in the field of system stability.
The tool allows to analyse an influence of torsion stiffness, torsion
damping, inertia moments of the motor and the load and controller(s)
parameters. The sensitivity and tolerance are monitored in terms of
the impact of parameter change on the response in the form of system
step response and system frequency-response logarithmic
characteristics. The Symbolic Math Toolbox for expression of the
final shape of analysed system functions was used. The sensitivity
and tolerance are graphically represented as 2D graph of sensitivity
or tolerance of the system function and 3D/2D static/interactive graph
of step/frequency response.
Abstract: The building sector is responsible, in many
industrialized countries, for about 40% of the total energy
requirements, so it seems necessary to devote some efforts in this
area in order to achieve a significant reduction of energy
consumption and of greenhouse gases emissions.
The paper presents a study aiming at providing a design
methodology able to identify the best configuration of the system
building/plant, from a technical, economic and environmentally point
of view.
Normally, the classical approach involves a building's energy
loads analysis under steady state conditions, and subsequent selection
of measures aimed at improving the energy performance, based on
previous experience made by architects and engineers in the design
team. Instead, the proposed approach uses a sequence of two wellknown
scientifically validated calculation methods (TRNSYS and
RETScreen), that allow quite a detailed feasibility analysis.
To assess the validity of the calculation model, an existing,
historical building in Central Italy, that will be the object of
restoration and preservative redevelopment, was selected as a casestudy.
The building is made of a basement and three floors, with a
total floor area of about 3,000 square meters.
The first step has been the determination of the heating and
cooling energy loads of the building in a dynamic regime by means,
which allows simulating the real energy needs of the building in
function of its use. Traditional methodologies, based as they are on
steady-state conditions, cannot faithfully reproduce the effects of
varying climatic conditions and of inertial properties of the structure.
With this model is possible to obtain quite accurate and reliable
results that allow identifying effective combinations building-HVAC
system.
The second step has consisted of using output data obtained as
input to the calculation model, which enables to compare different
system configurations from the energy, environmental and financial
point of view, with an analysis of investment, and operation and
maintenance costs, so allowing determining the economic benefit of
possible interventions.
The classical methodology often leads to the choice of
conventional plant systems, while our calculation model provides a
financial-economic assessment for innovative energy systems and
low environmental impact.
Computational analysis can help in the design phase, particularly
in the case of complex structures with centralized plant systems, by
comparing the data returned by the calculation model for different
design options.
Abstract: At present, the cascade PID control is widely used to
control the superheating temperature (main steam temperature). As
Main Steam Temperature has the characteristics of large inertia, large
time-delay and time varying, etc., conventional PID control strategy
cannot achieve good control performance. In order to overcome the
bad performance and deficiencies of main steam temperature control
system, Model Free Adaptive Control (MFAC) - P cascade control
system is proposed in this paper. By substituting MFAC in PID of the
main control loop of the main steam temperature control, it can
overcome time delays, non-linearity, disturbance and time variation.
Abstract: The reliability of the filtered HVBK model is now
investigated via some large eddy simulations (LES) of freely
decaying isotropic superfluid turbulence. For homogeneous
turbulence at very high Reynolds numbers, comparison of the terms
in the spectral kinetic energy budget equation indicates, in the
energy-containing range, that the production and energy transfer
effects become significant except for dissipation. In the inertial range,
where the two fluids are perfectly locked, the mutual friction maybe
neglected with respect to other terms. Also, the LES results for the
other terms of the energy balance are presented.
Abstract: Prior literature on innovation diffusion or acceptance has almost exclusively concentrated on consumers’ positive attitudes and behaviors for new products/services. Consumers’ negative attitudes or behaviors to innovations have received relatively little marketing attention, but it happens frequently in practice. This study discusses consumer psychological factors when they try to learn or use new technologies. According to recent research, technological innovation acceptance has been considered as a dynamic or mediated process. This research argues that consumers can experience inertia and emotions in the initial use of new technologies. However, given such consumer psychology, the argument can be made as to whether the inclusion of consumer inertia (routine seeking and cognitive rigidity) and emotions increases the predictive power of new technology acceptance model. As data from the empirical study find, the process is potentially consumer emotion changing (independent of performance benefits) because of technology complexity and consumer inertia, and impact innovative technology use significantly. Finally, the study presents the superior predictability of the hypothesized model, which let managers can better predict and influence the successful diffusion of complex technological innovations.
Abstract: This paper introduces a comparative study between the main GPS\INS coupling schemes, this will include the loosely coupled and tightly coupled configurations, several types of situations and operational conditions, in which the data fusion process is done using Kalman filtering. This will include the importance of sensors calibration as well as the alignment of the strap down inertial navigation system. The limitations of the inertial navigation systems are investigated.
Abstract: Two multisensor system architectures for navigation
and guidance of small Unmanned Aircraft (UA) are presented and
compared. The main objective of our research is to design a compact,
light and relatively inexpensive system capable of providing the
required navigation performance in all phases of flight of small UA,
with a special focus on precision approach and landing, where Vision
Based Navigation (VBN) techniques can be fully exploited in a
multisensor integrated architecture. Various existing techniques for
VBN are compared and the Appearance-Based Navigation (ABN)
approach is selected for implementation. Feature extraction and
optical flow techniques are employed to estimate flight parameters
such as roll angle, pitch angle, deviation from the runway centreline
and body rates. Additionally, we address the possible synergies of
VBN, Global Navigation Satellite System (GNSS) and MEMS-IMU
(Micro-Electromechanical System Inertial Measurement Unit)
sensors, and the use of Aircraft Dynamics Model (ADM) to provide
additional information suitable to compensate for the shortcomings of
VBN and MEMS-IMU sensors in high-dynamics attitude
determination tasks. An Extended Kalman Filter (EKF) is developed
to fuse the information provided by the different sensors and to
provide estimates of position, velocity and attitude of the UA
platform in real-time. The key mathematical models describing the
two architectures i.e., VBN-IMU-GNSS (VIG) system and VIGADM
(VIGA) system are introduced. The first architecture uses VBN
and GNSS to augment the MEMS-IMU. The second mode also
includes the ADM to provide augmentation of the attitude channel.
Simulation of these two modes is carried out and the performances of
the two schemes are compared in a small UA integration scheme (i.e.,
AEROSONDE UA platform) exploring a representative cross-section
of this UA operational flight envelope, including high dynamics
manoeuvres and CAT-I to CAT-III precision approach tasks.
Simulation of the first system architecture (i.e., VIG system) shows
that the integrated system can reach position, velocity and attitude
accuracies compatible with the Required Navigation Performance
(RNP) requirements. Simulation of the VIGA system also shows
promising results since the achieved attitude accuracy is higher using
the VBN-IMU-ADM than using VBN-IMU only. A comparison of
VIG and VIGA system is also performed and it shows that the
position and attitude accuracy of the proposed VIG and VIGA
systems are both compatible with the RNP specified in the various
UA flight phases, including precision approach down to CAT-II.
Abstract: Flow coastdown phenomena are very important to secure nuclear fuel integrity during loss of off-site power accidents. In this study, primary coolant flow coastdown phenomena are investigated for the Jordan Research and Training Reactor (JRTR) using a simulation software package, Modular Modeling System (MMS). Two MMS models are built. The first one is a simple model to investigate the characteristics of the primary coolant pump only. The second one is a model for a simulation of the Primary Coolant System (PCS) loop, in which all the detailed design data of the JRTR PCS system are modeled, including the geometrical arrangement data. The same design data for a PCS pump are used for both models. Coastdown curves obtained from the two models are compared to study the PCS loop coolant inertia effect on a flow coastdown. Results showed that the loop coolant inertia effect is found to be small in the JRTR PCS loop, i.e., about one second increases in a coastdown half time required to halve the coolant flow rate. The effects of different flywheel inertia on the flow coastdown are also investigated. It is demonstrated that the coastdown half time increases with the flywheel inertia linearly. The designed coastdown half time is proved to be well above the design requirement for the fuel integrity.
Abstract: Sandwich construction is widely accepted as a method of construction especially in the aircraft industry. It is a type of stressed skin construction formed by bonding two thin faces to a thick core, the faces resist all of the applied edge loads and provide all or nearly all of the required rigidities, the core spaces the faces to increase cross section moment of inertia about common neutral axis and transmit shear between them provides a perfect bond between core and faces is made.
Material for face sheets can be of metal or reinforced plastics laminates, core material can be metallic cores of thin sheets forming corrugation or honeycomb, or non metallic core of Balsa wood, plastic foams, or honeycomb made of reinforced plastics.
For in plane axial loading web core and web-foam core Sandwich panels can fail by local buckling of plates forming the cross section with buckling wave length of the order of length of spacing between webs.
In this study local buckling of web core and web-foam core Sandwich panels is carried out for given materials of facing and core, and given panel overall dimension for different combinations of cross section geometries.
The Finite Strip Method is used for the analysis, and Fortran based computer program is developed and used.
Abstract: A general decline in the cost, size, and power requirements of electronics is accelerating the adoption of integrated GPS/INS technologies in consumer applications such Land Vehicle Navigation. Researchers have looking for ways to eliminate additional components from product designs. One possibility is to drop one or more of the relatively expensive gyroscopes from microelectromechanical system (MEMS) versions of inertial measurement units (IMUs). For land vehicular use, the most important gyroscope is the vertical gyro that senses the heading of the vehicle and two horizontal accelerometers for determining the velocity of the vehicle. This paper presents a simplified integration algorithm for strap down (ParIMU)\GPS combination, with data post processing for the determination of 2-D components of position (trajectory), velocity and heading. In the present approach we have neglected earth rotation and gravity variations, because of the poor gyroscope sensitivities of the low-cost IMU and because of the relatively small area of the trajectory.
Abstract: Accurate dynamic modeling and analysis of flexible link manipulator (FLM) with non linear dynamics is very difficult due to distributed link flexibility and few studies have been conducted based on assumed modes method (AMM) and finite element models. In this paper a nonlinear dynamic model with first two elastic modes is derived using combined Euler/Lagrange and AMM approaches. Significant dynamics associated with the system such as hub inertia, payload, structural damping, friction at joints, combined link and joint flexibility are incorporated to obtain the complete and accurate dynamic model. The response of the FLM to the applied bang-bang torque input is compared against the models derived from LS-DYNA finite element discretization approach and linear finite element models. Dynamic analysis is conducted using LS-DYNA finite element model which uses the explicit time integration scheme to simulate the system. Parametric study is conducted to show the impact payload mass. A numerical result shows that the LS-DYNA model gives the smooth hub-angle profile.