Abstract: A class of implicit systems is known as a more
generalized class of systems than a class of explicit systems. To
establish a control method for such a generalized class of systems, we
adopt model predictive control method which is a kind of optimal
feedback control with a performance index that has a moving
initial time and terminal time. However, model predictive control
method is inapplicable to systems whose all state variables are not
exactly known. In other words, model predictive control method is
inapplicable to systems with limited measurable states. In fact, it
is usual that the state variables of systems are measured through
outputs, hence, only limited parts of them can be used directly. It is
also usual that output signals are disturbed by process and sensor
noises. Hence, it is important to establish a state estimation method
for nonlinear implicit systems with taking the process noise and
sensor noise into consideration. To this purpose, we apply the model
predictive control method and unscented Kalman filter for solving
the optimization and estimation problems of nonlinear implicit
systems, respectively. The objective of this study is to establish a
model predictive control with unscented Kalman filter for nonlinear
implicit systems.
Abstract: With the spread of EVs (electric Vehicles), the ride
comfort has been gaining a lot of attention. The influence of the lateral
acceleration is important for the improvement of ride comfort of EVs
as well as the longitudinal acceleration, especially upon turning of
the vehicle. Therefore, this paper proposes a practical optimal speed
control method to greatly improve the ride comfort in the vehicle
turning situation. For consturcting this method, effective criteria that
can appropriately evaluate deterioration of ride comfort is derived.
The method can reduce the influence of both the longitudinal and
the lateral speed changes for providing a confortable ride. From
several simulation results, we can see the fact that the method can
prevent aggravation of the ride comfort by suppressing the influence
of longitudinal speed change in the turning situation. Hence, the
effectiveness of the method is recognized.
Abstract: The development of solutions to improve the resistance of buildings to short-term dynamic loads, particularly impact load, is driven by the urgent demand worldwide on securing human life and critical infrastructures. The research training group GRK 2250/1 aims to develop mineral-bonded composites that allow the fabrication of thin-layered strengthening layers providing available concrete members with enhanced impact resistance. This paper presents the development of 3D woven wire cellular structures that can be used as innovative reinforcement for targeted composites. 3D woven wire cellular structures are truss-like architectures that can be fabricated in an automatized process with a great customization possibility. The specific architecture allows this kind of structures to have good load bearing capability and forming behavior, which is of great potential to give strength against impact loading. An appropriate combination of topology and material enables an optimal use of thin-layered reinforcement in concrete constructions.
Abstract: This study investigates the benefits of implementing the semi-active devices in relation to passive viscous damping in the context of seismically isolated bridge structures. Since the intrinsically nonlinear nature of semi-active devices prevents the direct evaluation of Laplace transforms, frequency response functions are compiled from the computed time history response to sinusoidal and pulse-like seismic excitation. A simple semi-active control policy is used in regard to passive linear viscous damping and an optimal non-causal semi-active control strategy. The control strategy requires optimization. Euler-Lagrange equations are solved numerically during this procedure. The optimal closed-loop performance is evaluated for an idealized controllable dash-pot. A simplified single-degree-of-freedom model of an isolated bridge is used as numerical example. Two bridge cases are investigated. These cases are; bridge deck without the isolation bearing and bridge deck with the isolation bearing. To compare the performances of the passive and semi-active control cases, frequency dependent acceleration, velocity and displacement response transmissibility ratios Ta(w), Tv(w), and Td(w) are defined. To fully investigate the behavior of the structure subjected to the sinusoidal and pulse type excitations, different damping levels are considered. Numerical results showed that, under the effect of external excitation, bridge deck with semi-active control showed better structural performance than the passive bridge deck case.
Abstract: Teaching Object-Oriented Programming (OOP) as part of a Computing-related university degree is a very difficult task; the road to ensuring that students are actually learning object oriented concepts is unclear, as students often find it difficult to understand the concept of objects and their behavior. This problem is especially obvious in advanced programming modules where Design Pattern and advanced programming features such as Multi-threading and animated GUI are introduced. Looking at the students’ performance at their final year on a university course, it was obvious that the level of students’ understanding of OOP varies to a high degree from one student to another. Students who aim at the production of Games do very well in the advanced programming module. However, the students’ assessment results of the last few years were relatively low; for example, in 2016-2017, the first quartile of marks were as low as 24.5 and the third quartile was 63.5. It is obvious that many students were not confident or competent enough in their programming skills. In this paper, the reasons behind poor performance in Advanced OOP modules are investigated, and a suggested practice for teaching OOP based on a complex case study is described and evaluated.
Abstract: Inclusive education stems from a philosophy and vision, which argues that all children should learn together at school. It is not only about treating all pupils in the same way. It is also about allowing all children to attend school without any restrictions. Ten primary school teachers in a circuit in Namibia volunteered to participate in face-to-face interviews about inclusive education. The teachers responded to three questions about their (i) understanding of inclusive education; (ii) whether inclusive education was implemented in primary schools; and (iii) whether they were able to work with learners with special needs. Findings indicated that teachers understood what inclusive education entailed; felt that inclusive education was not implemented in their primary schools, and they were unable to work with learners with special needs in their classrooms. Further, the teachers identified training and resources as important components of inclusive education. It is recommended that education authorities should perhaps verify the findings reported here as well as ensure that the concerns raised by the teachers are addressed.
Abstract: Most people see human faces in car front and back ends because of the process of pareidolia. 96 people were surveyed to see how many of them saw a face in the vehicle styling. Participants were aged 18 to 72 years. 94% of the participants saw faces in the front-end design of production models. All participants that recognized faces indicated that most styles showed some degree of an angry expression. It was found that women were more likely to see faces in inanimate objects. However, with respect to whether women were more likely to perceive anger in the vehicle design, the results need further clarification. Survey responses were correlated to the design features of vehicles to determine what cues the respondents were likely looking at when responding. Whether the features looked anthropomorphic was key to anger perception. Features such as the headlights which could represent eyes and the air intake that could represent a mouth had high correlations to trends in scores. Results are compared among models, makers, by groupings of body styles classifications for the top 12 brands sold in the US, and by year for the top 20 models sold in the US in 2016. All of the top models sold increased in perception of an angry expression over the last 20 years or since the model was introduced, but the relative change varied by body style grouping.
Abstract: This paper presents analysis and characterization of
a piezoelectric micro-generator for energy harvesting application.
A low-cost experimental prototype was designed to operate as
piezoelectric micro-generator in the laboratory. An input acceleration
of 9.8m/s2 using a sine signal (peak-to-peak voltage: 1V, offset
voltage: 0V) at frequencies ranging from 10Hz to 160Hz generated
a maximum average power of 432.4μW (linear mass position =
25mm) and an average power of 543.3μW (angular mass position
= 35°). These promising results show that the prototype can be
considered for low consumption load application as an energy
harvesting micro-generator.
Abstract: Dangerous of climate change is now global problem and as such has a strategic priority also for the European Union. Europe and European citizens try to do their best to cut greenhouse gas emissions, moreover they substantially encourage other nations and regions to follow the same way. The European Commission and a number of Member States have developed adaptation strategies in order to help strengthen EU's resilience to the inevitable impacts of climate change. The EU has long been a driving force in international negotiations on climate change and was instrumental in the development of the UN Framework Convention on Climate Change. As the world's leading donor of development aid, the EU also provides substantial funding to help developing countries tackle climate change problem. Global warming influences human health, biodiversity, ecosystems but also many social and economic sectors. The aim of this paper is to focus on impact of claimant change on for food security. Food security challenges are directly related to globalization, climate change. It means that current and future food policy is exposed to all cross-cutting and that must be linked with environmental and climate targets, which supposed to be achieved. In the 7th EAP —The new general Union Environment Action Program to 2020, called “Living well, within the limits of our planet” EU has agreed to step up its efforts to protect natural capital, stimulate resource efficient, low carbon growth and innovation, and safeguard people’s health and wellbeing– while respecting the Earth’s natural limits.
Abstract: Spectrum underutilization has made cognitive
radio a promising technology both for current and future
telecommunications. This is due to the ability to exploit the unused
spectrum in the bands dedicated to other wireless communication
systems, and thus, increase their occupancy. The essential function,
which allows the cognitive radio device to perceive the occupancy
of the spectrum, is spectrum sensing. In this paper, the performance
of modern adaptations of the four most widely used spectrum
sensing techniques namely, energy detection (ED), cyclostationary
feature detection (CSFD), matched filter (MF) and eigenvalues-based
detection (EBD) is compared. The implementation has been
accomplished through the PlutoSDR hardware platform and the
GNU Radio software package in very low Signal-to-Noise Ratio
(SNR) conditions. The optimal detection performance of the
examined methods in a realistic implementation-oriented model is
found for the common relevant parameters (number of observed
samples, sensing time and required probability of false alarm).
Abstract: Computer-based optimization techniques can be employed to improve the efficiency of energy conversions processes, including reducing the aerodynamic loss in a thermal power plant turbomachine. In this paper, towards mitigating secondary flow losses, a design optimization workflow is implemented for the casing geometry of a 1.5 stage axial flow turbine that improves the turbine isentropic efficiency. The improved turbine is used in an open thermodynamic gas cycle with regeneration and cogeneration. Performance estimates are obtained by the commercial software Cycle – Tempo. Design and off design conditions are considered as well as variations in inlet air temperature. Reductions in both the natural gas specific fuel consumption and in CO2 emissions are predicted by using the gas turbine cycle fitted with the new casing design. These gains are attractive towards enhancing the competitiveness and reducing the environmental impact of thermal power plant.
Abstract: The cardiopulmonary signal monitoring, without the
usage of contact electrodes or any type of in-body sensors, has
several applications such as sleeping monitoring and continuous
monitoring of vital signals in bedridden patients. This system has
also applications in the vehicular environment to monitor the driver,
in order to avoid any possible accident in case of cardiac failure.
Thus, the bio-radar system proposed in this paper, can measure vital
signals accurately by using the Doppler effect principle that relates
the received signal properties with the distance change between the
radar antennas and the person’s chest-wall. Once the bio-radar aim
is to monitor subjects in real-time and during long periods of time,
it is impossible to guarantee the patient immobilization, hence their
random motion will interfere in the acquired signals. In this paper,
a mathematical model of the bio-radar is presented, as well as its
simulation in MATLAB. The used algorithm for breath rate extraction
is explained and a method for DC offsets removal based in a motion
detection system is proposed. Furthermore, experimental tests were
conducted with a view to prove that the unavoidable random motion
can be used to estimate the DC offsets accurately and thus remove
them successfully.
Abstract: Nowadays, the progressive decrease of primary natural resources and ongoing upward trend in terms of energy demand, have resulted in development of new generation technological processes which are focused on step-wise production and residues utilization. Thus, microalgae-based 3rd generation bioeconomy is considered one of the most promising approaches that allow production of value-added products and sophisticated utilization of residues biomass. In comparison to conventional biomass, microalgae can be cultivated in wide range of conditions without compromising food and feed production, and thus, addressing issues associated with negative social and environmental impacts. However, one of the most challenging tasks is to undergo seasonal variations and to achieve optimal growing conditions for indoor closed systems that can cover further demand for material and energetic utilization of microalgae. For instance, outdoor cultivation in St. Petersburg (Russia) is only suitable within rather narrow time frame (from mid-May to mid-September). At earlier and later periods, insufficient sunlight and heat for the growth of microalgae were detected. On the other hand, without additional physical effects, the biomass increment in summer is 3-5 times per week, depending on the solar radiation and the ambient temperature. In order to increase biomass production, scientists from all over the world have proposed various technical solutions for cultivators and have been studying the influence of various physical factors affecting biomass growth namely: magnetic field, radiation impact, and electric field, etc. In this paper, the influence of infrared radiation (IR) and fluorescent light on the growth rate of microalgae Chlorella sorokiniana has been studied. The cultivation of Chlorella sorokiniana was carried out in 500 ml cylindrical glass vessels, which were constantly aerated. To accelerate the cultivation process, the mixture was stirred for 15 minutes at 500 rpm following 120 minutes of rest time. At the same time, the metabolic needs in nutrients were provided by the addition of micro- and macro-nutrients in the microalgae growing medium. Lighting was provided by fluorescent lamps with the intensity of 2500 ± 300 lx. The influence of IR was determined using IR lamps with a voltage of 220 V, power of 250 W, in order to achieve the intensity of 13 600 ± 500 lx. The obtained results show that under the influence of fluorescent lamps along with the combined effect of active aeration and variable mixing, the biomass increment on the 2nd day was three times, and on the 7th day, it was eight-fold. The growth rate of microalgae under the influence of IR radiation was lower and has reached 22.6·106 cells·mL-1. However, application of IR lamps for the biomass growth allows maintaining the optimal temperature of microalgae suspension at approximately 25-28°C, which might especially be beneficial during the cold season in extreme climate zones.
Abstract: The use of waste rubber chips not only can be of great importance in terms of the environment, but also can be used to increase the shear strength of soils. The purpose of this study was to evaluate the variation of the internal friction angle of liquefiable sandy soil using waste rubber chips. For this purpose, the geotechnical properties of unmodified and modified soil samples by waste lining rubber chips have been evaluated and analyzed by performing the triaxial consolidated drained test. In order to prepare the laboratory specimens, the sandy soil in part of Rudsar shores in Gilan province, north of Iran with high liquefaction potential has been replaced by two percent of waste rubber chips. Samples have been compressed until reaching the two levels of density of 15.5 and 16.7 kN/m3. Also, in order to find the optimal length of chips in sandy soil, the rectangular rubber chips with the widths of 0.5 and 1 cm and the lengths of 0.5, 1, and 2 cm were used. The results showed that the addition of rubber chips to liquefiable sandy soil greatly increases the shear resistance of these soils. Also, it can be seen that decreasing the width and increasing the length-to-width ratio of rubber chips has a direct impact on the shear strength of the modified soil samples with rubber chips.
Abstract: Over the last decade due to climate change and a strategy of natural resources preservation, the interest for the aquatic biomass has dramatically increased. Along with mitigation of the environmental pressure and connection of waste streams (including CO2 and heat emissions), microalgae bioeconomy can supply food, feed, as well as the pharmaceutical and power industry with number of value-added products. Furthermore, in comparison to conventional biomass, microalgae can be cultivated in wide range of conditions without compromising food and feed production, thus addressing issues associated with negative social and the environmental impacts. This paper presents the state-of-the art technology for microalgae bioeconomy from cultivation process to production of valuable components and by-streams. Microalgae Chlorella sorokiniana were cultivated in the pilot-scale innovation concept in Hamburg (Germany) using different systems such as race way pond (5000 L) and flat panel reactors (8 x 180 L). In order to achieve the optimum growth conditions along with suitable cellular composition for the further extraction of the value-added components, process parameters such as light intensity, temperature and pH are continuously being monitored. On the other hand, metabolic needs in nutrients were provided by addition of micro- and macro-nutrients into a medium to ensure autotrophic growth conditions of microalgae. The cultivation was further followed by downstream process and extraction of lipids, proteins and saccharides. Lipids extraction is conducted in repeated-batch semi-automatic mode using hot extraction method according to Randall. As solvents hexane and ethanol are used at different ratio of 9:1 and 1:9, respectively. Depending on cell disruption method along with solvents ratio, the total lipids content showed significant variations between 8.1% and 13.9 %. The highest percentage of extracted biomass was reached with a sample pretreated with microwave digestion using 90% of hexane and 10% of ethanol as solvents. Proteins content in microalgae was determined by two different methods, namely: Total Kejadahl Nitrogen (TKN), which further was converted to protein content, as well as Bradford method using Brilliant Blue G-250 dye. Obtained results, showed a good correlation between both methods with protein content being in the range of 39.8–47.1%. Characterization of neutral and acid saccharides from microalgae was conducted by phenol-sulfuric acid method at two wavelengths of 480 nm and 490 nm. The average concentration of neutral and acid saccharides under the optimal cultivation conditions was 19.5% and 26.1%, respectively. Subsequently, biomass residues are used as substrate for anaerobic digestion on the laboratory-scale. The methane concentration, which was measured on the daily bases, showed some variations for different samples after extraction steps but was in the range between 48% and 55%. CO2 which is formed during the fermentation process and after the combustion in the Combined Heat and Power unit can potentially be used within the cultivation process as a carbon source for the photoautotrophic synthesis of biomass.
Abstract: Source apportionment using Dispersion model depends primarily on the quality of Emission Inventory. In the present study, a CMB receptor model has been used to identify the sources of PM2.5, while the AERMOD dispersion model has been used to account for missing sources of PM2.5 in the Emission Inventory. A statistical approach has been developed to quantify the missing sources not considered in the Emission Inventory. The inventory of each grid was improved by adjusting emissions based on road lengths and deficit in measured and modelled concentrations. The results showed that in CMB analyses, fugitive sources - soil and road dust - contribute significantly to ambient PM2.5 pollution. As a result, AERMOD significantly underestimated the ambient air concentration at most locations. The revised Emission Inventory showed a significant improvement in AERMOD performance which is evident through statistical tests.
Abstract: Acidification is a technique used in oil reservoirs
to improve annual production, reduce the skin and increase the
pressure of an oil well while eliminating the formation damage that
occurs during the drilling process, completion and, amongst others,
to create new channels allowing the easy circulation of oil around
a producing well. This is achieved by injecting an acidizing fluid
at a relatively low pressure to prevent fracturing formation. The
treatment fluid used depends on the type and nature of the reservoir
rock traversed as well as its petrophysical properties. In order to
understand the interaction mechanisms between the treatment fluids
used for the reservoir rock acidizing, several candidate wells for
stimulation were selected in the large Hassi Messaoud deposit in
southern Algeria. The stimulation of these wells is completed using
different fluids composed mainly of HCl acid with other additives
such as corrosion inhibitors, clay stabilizers and iron controllers.
These treatment fluids are injected over two phases, namely with
clean tube (7.5% HCl) and matrix aidizing with HCl (15%). The
stimulation results obtained are variable according to the type of
rock traversed and its mineralogical composition. These results show
that there has been an increase in production flow and head pressure
respectively from 1.99 m3 / h to 3.56 m3 / h and from 13 Kgf / cm2
to 20 kgf / cm2 in the sands formation having good petrophysical
properties of (porosity = 16%) and low amount of clay (Vsh = 6%).
Abstract: In this paper, an observer-based direct adaptive fuzzy sliding mode (OAFSM) algorithm is proposed. In the proposed algorithm, the zero-input dynamics of the plant could be unknown. The input connection matrix is used to combine the sliding surfaces of individual subsystems, and an adaptive fuzzy algorithm is used to estimate an equivalent sliding mode control input directly. The fuzzy membership functions, which were determined by time consuming try and error processes in previous works, are adjusted by adaptive algorithms. The other advantage of the proposed controller is that the input gain matrix is not limited to be diagonal, i.e. the plant could be over/under actuated provided that controllability and observability are preserved. An observer is constructed to directly estimate the state tracking error, and the nonlinear part of the observer is constructed by an adaptive fuzzy algorithm. The main advantage of the proposed observer is that, the measured outputs is not limited to the first entry of a canonical-form state vector. The closed-loop stability of the proposed method is proved using a Lyapunov-based approach. The proposed method is applied numerically on a multi-link robot manipulator, which verifies the performance of the closed-loop control. Moreover, the performance of the proposed algorithm is compared with some conventional control algorithms.
Abstract: The Oscillatory electroosmotic flow (OEOF) in power
law fluids through a microchannel is studied numerically. A
time-dependent external electric field (AC) is suddenly imposed
at the ends of the microchannel which induces the fluid motion.
The continuity and momentum equations in the x and y direction
for the flow field were simplified in the limit of the lubrication
approximation theory (LAT), and then solved using a numerical
scheme. The solution of the electric potential is based on the
Debye-H¨uckel approximation which suggest that the surface potential
is small,say, smaller than 0.025V and for a symmetric (z : z)
electrolyte. Our results suggest that the velocity profiles across
the channel-width are controlled by the following dimensionless
parameters: the angular Reynolds number, Reω, the electrokinetic
parameter, ¯κ, defined as the ratio of the characteristic length scale
to the Debye length, the parameter λ which represents the ratio
of the Helmholtz-Smoluchowski velocity to the characteristic length
scale and the flow behavior index, n. Also, the results reveal that
the velocity profiles become more and more non-uniform across the
channel-width as the Reω and ¯κ are increased, so oscillatory OEOF
can be really useful in micro-fluidic devices such as micro-mixers.
Abstract: From August to December of 2016, a diagnostic and strategic planning study was carried out on the supply chain of the company Agropecuaria GABO S.A. de C.V. The final product of the study was the development of the strategic plan and a project portfolio to meet the demands of the three links in the supply chain of the Roma tomato exported annually to the United States of America. In this project, the strategic objective of ensuring the proper handling of the product was selected and one of the goals associated with this was the employment of quantitative methods to support decision making. Considering the antecedents, the objective of this case study was to develop a model to analyze the behavioral dynamics in the distribution chain, from the logistics of storage and shipment of Roma tomato in 81-case pallets (11.5 kg per case), to the two pre-cooling rooms and eventual loading onto transports, seeking to reduce the bottleneck and the associated costs by means of a dynamic interface. The methodology used was that of system dynamics, considering four phases that were adapted to the purpose of the study: 1) the conceptualization phase; 2) the formulation phase; 3) the evaluation phase; and 4) the communication phase. The main practical conclusions lead to the possibility of reducing both the bottlenecks in the cooling rooms and the costs by simulating scenarios and modifying certain policies. Furthermore, the creation of the dynamic interface between the model and the stakeholders was achieved by generating interaction with buttons and simple instructions that allow making modifications and observing diverse behaviors.