Abstract: Microscopic simulation tool kits allow for
consideration of the two processes of railway operations and the
previous timetable production. Block occupation conflicts on both
process levels are often solved by using defined train priorities. These
conflict resolutions (dispatching decisions) generate reactionary
delays to the involved trains. The sum of reactionary delays is
commonly used to evaluate the quality of railway operations, which
describes the timetable robustness. It is either compared to an
acceptable train performance or the delays are appraised
economically by linear monetary functions. It is impossible to
adequately evaluate dispatching decisions without a well-founded
objective function. This paper presents a new approach for the
evaluation of dispatching decisions. The approach uses mode choice
models and considers the behaviour of the end-customers. These
models evaluate the reactionary delays in more detail and consider
other competing modes of transport. The new approach pursues the
coupling of a microscopic model of railway operations with the
macroscopic choice mode model. At first, it will be implemented for
railway operations process but it can also be used for timetable
production. The evaluation considers the possibility for the customer
to interchange to other transport modes. The new approach starts to
look at rail and road, but it can also be extended to air travel. The
result of mode choice models is the modal split. The reactions by the
end-customers have an impact on the revenue of the train operating
companies. Different purposes of travel have different payment
reserves and tolerances towards late running. Aside from changes to
revenues, longer journey times can also generate additional costs.
The costs are either time- or track-specific and arise from required
changes to rolling stock or train crew cycles. Only the variable values
are summarised in the contribution margin, which is the base for the
monetary evaluation of delays. The contribution margin is calculated
for different possible solutions to the same conflict. The conflict
resolution is optimised until the monetary loss becomes minimal. The
iterative process therefore determines an optimum conflict resolution
by monitoring the change to the contribution margin. Furthermore, a
monetary value of each dispatching decision can also be derived.
Abstract: In this study, we proposed two techniques to track the
maximum power point (MPPT) of a photovoltaic system. The first is
an intelligent control technique, and the second is robust used for
variable structure system. In fact the characteristics I-V and P–V of
the photovoltaic generator depends on the solar irradiance and
temperature. These climate changes cause the fluctuation of
maximum power point; a maximum power point tracking technique
(MPPT) is required to maximize the output power. For this we have
adopted a control by fuzzy logic (FLC) famous for its stability and
robustness. And a Siding Mode Control (SMC) widely used for
variable structure system. The system comprises a photovoltaic panel
(PV), a DC-DC converter, which is considered as an adaptation stage
between the PV and the load. The modelling and simulation of the
system is developed using MATLAB/Simulink. SMC technique
provides a good tracking speed in fast changing irradiation and when
the irradiation changes slowly or it is constant the panel power of
FLC technique presents a much smoother signal with less
fluctuations.
Abstract: Rehabilitation of dam components such as foundations, buttresses, spillways and overtopping protection require a wide range of construction and design methodologies. Geotechnical Engineering considerations play an important role in the design and construction of foundations of new dams. Much investigation is required to assess and evaluate the existing dams. The application of roller compacting concrete (RCC) has been accepted as a new method for constructing new dams or rehabilitating old ones. In the past 40 years there have been so many changes in the usage of RCC and now it is one of most satisfactory solutions of water and hydropower resource throughout the world. The considerations of rehabilitation and construction of dams might differ due to upstream reservoir and its influence on penetrating and dewatering of downstream, operations requirements and plant layout. One of the advantages of RCC is its rapid placement which allows the dam to be operated quickly. Unlike ordinary concrete it is a drier mix, and stiffs enough for compacting by vibratory rollers. This paper evaluates some different aspects of RCC and focuses on its preparation progress.
Abstract: The present study was carried out to investigate the
effect of alloying elements and thermo-mechanical treatment (TMT)
i.e. hot rolling and forging with different reduction ratios on the
hardness (HV) and impact toughness (J) of heat-treated low alloy
steels. An understanding of the combined effect of TMT and alloying
elements and by measuring hardness, impact toughness, resulting
from different heat treatment following TMT of the low alloy steels,
it is possible to determine which conditions yielded optimum
mechanical properties and high strength to weight ratio.
Experimental Correlations between hot work reduction ratio,
hardness and impact toughness for thermo-mechanically heat treated
low alloy steels are analyzed quantitatively, and both regression and
mathematical hardness and impact toughness models are developed.
Abstract: This work sets out to debate the tensions involved in
the processes of contamination and self-purification in the urban
space, particularly in the streams that run through the Buenos Aires
metropolitan area. For much of their course, those streams are piped;
their waters do not come into contact with the outdoors until they
have reached deeply impoverished urban areas with high levels of
environmental contamination. These are peripheral zones that, until
thirty years ago, were marshlands and fields. They are now densely
populated areas largely lacking in urban infrastructure.
The Cárcova neighborhood, where this project is underway, is in
the José León Suárez section of General San Martín county, Buenos
Aires province. A stretch of José León Suarez canal crosses the
neighborhood. Starting upstream, this canal carries pollutants due to
the sewage and industrial waste released into it. Further downstream,
in the neighborhood, domestic drainage is poured into the stream. In
this paper, we formulate a hypothesis diametrical to the one that
holds that these neighborhoods are the primary source of
contamination, suggesting instead that in the stretch of the canal that
runs through the neighborhood the stream’s waters are actually
cleaned and the sediments accumulate pollutants. Indeed, the
stretches of water that runs through these neighborhoods act as water
processing plants for the metropolis.
This project has studied the different organic-load polluting
contributions to the water in a certain stretch of the canal, the
reduction of that load over the course of the canal, and the
incorporation of pollutants into the sediments. We have found that
the surface water has considerable ability to self-purify, mostly due to
processes of sedimentation and adsorption. The polluting load is
accumulated in the sediments where that load stabilizes slowly by
means of anaerobic processes. In this study, we also investigated the
risks of sediment management and the use of the processes studied
here in controlled conditions as tools of environmental restoration.
Abstract: Ulexite (Na2O.2CaO.5B2O3.16H2O) is boron mineral
that is found in large quantities in the Turkey and world. In this
study, the dissolution of this mineral in the disodium hydrogen
phosphate solutions has been studied. Temperature, concentration,
stirring speed, solid liquid ratio and particle size were selected as
parameters. The experimental results were successfully correlated by
linear regression using Statistica program. Dissolution curves were
evaluated shrinking core models for solid-fluid systems. It was
observed that increase in the reaction temperature and decrease in the
solid/liquid ratio causes an increase the dissolution rate of ulexite.
The activation energy was found to be 63.4 kJ/mol. The leaching of
ulexite was controlled by chemical reaction.
Abstract: Fly ash (FA) thanks to the significant presence of SiO2
and Al2O3 as the main components is a potential raw material for
geopolymers production. Mechanical activation is a method for
improving FA reactivity and also the porosity of final mixture; those
parameters can be analysed through sorption properties. They have
direct impact on the durability of fly ash based geopolymer mortars.
In the paper, effect of FA fineness on sorption properties of
geopolymers based on sodium silicate, as well as relationship
between fly ash fineness and apparent density, compressive and
flexural strength of geopolymers are presented. The best results in the
evaluated area reached the sample H1, which contents the highest
portion of particle under 20μm (100% of GFA). The interdependence
of individual tested properties was confirmed for geopolymer
mixtures corresponding to those in the cement based mixtures: higher
is portion of fine particles < 20μm, higher is strength, density and
lower are sorption properties. The compressive strength as well as
sorption parameters of the geopolymer can be reasonably controlled
by grinding process and also ensured by the higher share of fine
particle (to 20μm) in total mass of the material.
Abstract: The use of energy dissipation systems for seismic applications has increased worldwide, thus it is necessary to develop practical and modern criteria for their optimal design. Here, a direct displacement-based seismic design approach for frame buildings with hysteretic energy dissipation systems (HEDS) is applied. The building is constituted by two individual structural systems consisting of: 1) a main elastic structural frame designed for service loads; and 2) a secondary system, corresponding to the HEDS, that controls the effects of lateral loads. The procedure implies to control two design parameters: a) the stiffness ratio (α=Kframe/Ktotal system), and b) the strength ratio (γ=Vdamper/Vtotal system). The proposed damage-controlled approach contributes to the design of a more sustainable and resilient building because the structural damage is concentrated on the HEDS. The reduction of the design displacement spectrum is done by means of a damping factor (recently published) for elastic structural systems with HEDS, located in Mexico City. Two limit states are verified: serviceability and near collapse. Instead of the traditional trial-error approach, a procedure that allows the designer to establish the preliminary sizes of the structural elements of both systems is proposed. The design methodology is applied to an 8-story steel building with buckling restrained braces, located in soft soil of Mexico City. With the aim of choosing the optimal design parameters, a parametric study is developed considering different values of હ and . The simplified methodology is for preliminary sizing, design, and evaluation of the effectiveness of HEDS, and it constitutes a modern and practical tool that enables the structural designer to select the best design parameters.
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: Cesium iodide (CsI) melt was injected into anodic aluminum oxide (AAO) template and was solidified to CsI column. The controllable AAO channel size (10~500 nm) can makes CsI column size from 10 to 500 nm in diameter. In order to have a shorter light irradiate from each singe CsI column top to bottom the AAO template was coated a TiO2 nano-film. The TiO2 film acts a refraction film and makes X-ray has a shorter irradiation path in the CsI crystal making a stronger the photo-electron signal. When the incidence light irradiate from air (R=1.0) to CsI’s first surface (R=1.84) the first refraction happen, the first refraction continue into TiO2 film (R=2.88) and produces the low angle of the second refraction. Then the second refraction continue into AAO wall (R=1.78) and produces the third refraction after refractions between CsI and AAO wall (R=1.78) produce the fourth refraction. The incidence light through TiO2 filmand the first surface of CsI then arrive to the second surface of CsI. Therefore, the TiO2 film can has shorter refraction path of incidence light and increase the photo-electron conversion efficiency.
Abstract: This paper presents dynamic models of distributed
generators (DG) and investigates dynamic behavior of the DG units
in the micro grid system. The DG units include photovoltaic and fuel
cell sources. The voltage source inverter is adopted since the
electronic interface which can be equipped with its controller to keep
stability of the micro grid during small signal dynamics. This paper
also introduces power management strategies and implements the DG
load sharing concept to keep the micro grid operation in gridconnected
and islanding modes of operation. The results demonstrate
the operation and performance of the photovoltaic and fuel cell as
distributed generators in a micro grid. The entire control system in
the micro grid is developed by combining the benefits of the power
control and the voltage control strategies. Simulation results are all
reported, confirming the validity of the proposed control technique.
Abstract: The quality and condition of perishable products
delivered to the market and their subsequent selling prices are
directly affected by the care taken during harvesting and handling.
Mechanical injury, in fact, occurs at all stages, from pre-harvest
operations through post-harvest handling, packing and transport to
the market. The main implications of this damage are the reduction of
the product’s quality and economical losses related to the shelf life
diminution. For most perishable products, the shelf life is relatively
short and it is typically dictated by microbial growth related to the
application of dynamic and static loads during transportation. This
paper presents the correlation between vibration levels and
microbiological growth on strawberries and woodland strawberries
and detects the presence of volatile organic compounds (VOC) in
order to develop an intelligent logistic unit capable of monitoring
VOCs using a specific sensor system. Fresh fruits were exposed to
vibrations by means of a vibrating table in a temperature-controlled
environment. Microbiological analyses were conducted on samples,
taken at different positions along the column of the crates. The values
obtained were compared with control samples not exposed to
vibrations and the results show that different positions along the
column influence the development of bacteria, yeasts and filamentous
fungi.
Abstract: In our research we aimed to test a managerial
approach for the fuzzy front end (FFE) of innovation by creating
controlled experiment/ business case in a breakthrough innovation
development. The experiment was in the sport industry and covered
all aspects of the customer discovery stage from ideation to
prototyping followed by patent application. In the paper we describe
and analyze mile stones, tasks, management challenges, decisions
made to create the break through innovation, evaluate overall
managerial efficiency that was at the considered FFE stage.
We set managerial outcome of the FFE stage as a valid product
concept in hand. In our paper we introduce hypothetical construct
“Q-factor” that helps us in the experiment to distinguish quality of
FFE outcomes.
The experiment simulated for entrepreneur the FFE of innovation
and put on his shoulders responsibility for the outcome of valid
product concept. While developing managerial approach to reach the
outcome there was a decision to look on product concept from the
cognitive psychology and cognitive science point of view. This view
helped us to develop the profile of a person whose projection (mental
representation) of a new product could optimize for a manager or
entrepreneur FFE activities. In the experiment this profile was tested
to develop breakthrough innovation for swimmers. Following the
managerial approach the product concept was created to help
swimmers to feel/sense water. The working prototype was developed
to estimate the product concept validity and value added effect for
customers.
Based on feedback from coachers and swimmers there were strong
positive effect that gave high value for customers, and for the
experiment – the valid product concept being developed by proposed
managerial approach for the FFE.
In conclusions there is a suggestion of managerial approach that
was derived from experiment.
Abstract: Flexible AC Transmission Systems (FACTS) is
granting a new group of advanced power electronic devices emerging
for enhancement of the power system performance. Unified Power
Flow Controller (UPFC) is a recent version of FACTS devices for
power system applications. The back-up energy supply system
incorporated with UPFC is providing a complete control of real and
reactive power at the same time and hence is competent to improve
the performance of an electrical power system. In this article, backup
energy supply unit such as superconducting magnetic energy storage
(SMES) is integrated with UPFC. In addition, comparative
exploration of UPFC–battery, UPFC–UC and UPFC–SMES
performance is evaluated through the vibrant simulation by using
MATLAB/Simulink software.
Abstract: Problems insulation of building structures is often
closely connected with the problem of moisture remediation. In the
case of historic buildings or if only part of the redevelopment of
envelope of structures, it is not possible to apply the classical external
thermal insulation composite systems. This application is mostly
effective thermal insulation plasters with high porosity and controlled
capillary properties which assures improvement of thermal properties
construction, its diffusion openness towards the external environment
and suitable treatment capillary properties of preventing the
penetration of liquid moisture and salts thereof toward the outer
surface of the structure.
With respect to the current trend of reducing the energy
consumption of building structures and reduce the production of CO2
is necessary to develop capillary-active materials characterized by
their low density, low thermal conductivity while maintaining good
mechanical properties. The aim of researchers at the Faculty of Civil
Engineering, Brno University of Technology is the development and
study of hygrothermal behaviour of optimal materials for thermal
insulation and rehabilitation of building structures with the possible
use of alternative, less energy demanding binders in comparison with
conventional, frequently used binder, which represents cement.
The paper describes the evaluation of research activities aimed at
the development of thermal insulation and repair materials using
lightweight aggregate and alternative binders such as metakaolin and
finely ground fly ash.
Abstract: The introduction of degradable plastic materials into
agricultural sectors has represented a promising alternative to
promote green agriculture and environmental friendly of modern
farming practices. Major challenges of developing degradable
agricultural films are to identify the most feasible types of
degradation mechanisms, composition of degradable polymers and
related processing techniques. The incorrect choice of degradable
mechanisms to be applied during the degradation process will cause
premature losses of mechanical performance and strength. In order to
achieve controlled process of agricultural film degradation, the
compositions of degradable agricultural film also important in order
to stimulate degradation reaction at required interval of time and to
achieve sustainability of the modern agricultural practices. A set of
photodegradable polyethylene based agricultural film was developed
and produced, following the selective optimization of processing
parameters of the agricultural film manufacturing system. Example of
agricultural films application for oil palm seedlings cultivation is
presented.
Abstract: Gypsum (CaSO4.2H2O) is a mineral that is found in
large quantities in the Turkey and in the World. In this study, the
dissolution of this mineral in the diammonium hydrogen phosphate
solutions has been studied. The dissolution and dissolution kinetics of
gypsum in diammonium hydrogen phosphate solutions will be useful
for evaluating of solid wastes containing gypsum. Parameters such as
diammonium hydrogen phosphate concentration, temperature and
stirring speed affecting on the dissolution rate of the gypsum in
diammonium hydrogen phosphate solutions were investigated. In
experimental studies have researched effectiveness of the selected
parameters. The dissolution of gypsum were examined in two parts at
low and high temperatures. The experimental results were
successfully correlated by linear regression using Statistica program.
Dissolution curves were evaluated shrinking core models for solidfluid
systems. The activation energy was found to be 34.58 kJ/mol
and 44.45 kJ/mol for the low and the high temperatures. The
dissolution of gypsum was controlled by chemical reaction both low
temperatures and high temperatures.
Abstract: In this paper, a direct power control (DPC)
strategies have been investigated in order to control a high
power AC/DC converter with time variable load. This converter
is composed of a three level three phase neutral point clamped
(NPC) converter as rectifier and an H-bridge four quadrant
current control converter. In the high power application,
controller not only must adjust the desire outputs but also
decrease the level of distortions which are injected to the network
from the converter. Regarding to this reason and nonlinearity
of the power electronic converter, the conventional controllers
cannot achieve appropriate responses. In this research, the
precise mathematical analysis has been employed to design the
appropriate controller in order to control the time variable
load. A DPC controller has been proposed and simulated using
Matlab/ Simulink. In order to verify the simulation result, a real
time simulator- OPAL-RT- has been employed. In this paper,
the dynamic response and stability of the high power NPC
with variable load has been investigated and compared with
conventional types using a real time simulator. The results proved
that the DPC controller is more stable and has more precise
outputs in comparison with conventional controller.
Abstract: Parabolic solar trough systems have seen limited
deployments in cold northern climates as they are more suitable for
electricity production in southern latitudes. A numerical dynamic
model is developed to simulate troughs installed in cold climates and
validated using a parabolic solar trough facility in Winnipeg. The
model is developed in Simulink and will be utilized to simulate a trigeneration
system for heating, cooling and electricity generation in
remote northern communities. The main objective of this simulation
is to obtain operational data of solar troughs in cold climates and use
the model to determine ways to improve the economics and address
cold weather issues.
In this paper the validated Simulink model is applied to simulate a
solar assisted absorption cooling system along with electricity
generation using Organic Rankine Cycle (ORC) and thermal storage.
A control strategy is employed to distribute the heated oil from solar
collectors among the above three systems considering the
temperature requirements. This modelling provides dynamic
performance results using measured meteorological data recorded
every minute at the solar facility location. The purpose of this
modeling approach is to accurately predict system performance at
each time step considering the solar radiation fluctuations due to
passing clouds. Optimization of the controller in cold temperatures is
another goal of the simulation to for example minimize heat losses in
winter when energy demand is high and solar resources are low.
The solar absorption cooling is modeled to use the generated heat
from the solar trough system and provide cooling in summer for a
greenhouse which is located next to the solar field.
The results of the simulation are presented for a summer day in
Winnipeg which includes comparison of performance parameters of
the absorption cooling and ORC systems at different heat transfer
fluid (HTF) temperatures.
Abstract: In this paper we propose a discrete tracking control of
nonholonomic mobile robots with two degrees of freedom. The
electromechanical model of a mobile robot moving on a horizontal
surface without slipping, with two rear wheels controlled by two
independent DC electric, and one front roal wheel is considered. We
present backstepping design based on the Euler approximate discretetime
model of a continuous-time plant. Theoretical considerations are
verified by numerical simulation.