Abstract: In this paper static scheme of under-frequency based load shedding is considered for chemical and petrochemical industries with islanded distribution networks relying heavily on the primary commodity to ensure minimum production loss, plant downtime or critical equipment shutdown. A simplistic methodology is proposed for in-house implementation of this scheme using underfrequency relays and a step by step guide is provided including the techniques to calculate maximum percentage overloads, frequency decay rates, time based frequency response and frequency based time response of the system. Case study of FFL electrical system is utilized, presenting the actual system parameters and employed load shedding settings following the similar series of steps. The arbitrary settings are then verified for worst overload conditions (loss of a generation source in this case) and comprehensive system response is then investigated.
Abstract: Investigations on the accumulation of heavy metals in
water and sediments of river Ogbese were carried out between
December 2010 and February 2011 using Atomic Absorption
Spectrophotometer. Etheria elliptica a sessile organism was also used
to determine the concentration of heavy metal in the aquatic
environmental. In water, Cu had the highest concentration (0.55 –
0.13 mg/l ±0.1) while in sediments, the highest value obtained was in
Fe (1.46-3.89mg/l±0.27). The minimum concentrations recorded
were in Pb; which was below detectable level. The result also
revealed that the shell accumulate more heavy metals than the flesh
of the mussel with Cu in the shell exhibiting a negative correlation
with all the metals in the flesh. However, the condition factor (K)
value is 6.44, an indication of good health. The length-weight
relationship is expressed as W = -0.48 x L 1.94 (r2 = 0.29) showing the
growth pattern to be negatively allometric.
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: Freelancing in IT has seen an increased popularity
during the last years mainly because of the fast Internet adoption in
the countries with emerging economies, correlated with the
continuous seek for reduced development costs as well with the rise
of online platforms which address planning, coordination and various
development tasks. This paper conducts an overview of the most
relevant Freelance Marketplaces available and studies the market
structure, distribution of the workforce and trends in IT freelancing.
Abstract: The paper shows the necessity of farm diversification
in accordance with the current trends in agricultural sector of
Georgia. The possibilities for the diversification and the
corresponding economic policy are suggested.
The causes that hinder diversification of farms are revealed,
possibilities of diversification are identified and the ability of
increasing employment through diversification is proved. Index of
harvest diversification is calculated based on the areas used for
cereals and legumes, potatoes and vegetables and other food crops.
Crop and livestock production indexes are analyzed; correlation
between crop capacity index and value added per worker and per
hectare is studied.
Based on the research farm diversification strategies and priorities
of corresponding economic policy are presented. Based on the
conclusions relevant recommendations are suggested.
Abstract: Family has a crucial role in maintaining the
physical, social and mental health of the children. Most of the
mental and anxiety problems of children reflect the complex
interpersonal situations among family members, especially parents.
In other words, anxiety problems of the children are correlated
with deficit relationships of family members and improper
childrearing styles. The parental child rearing styles leads to
positive and negative consequences which affect the children’s
mental health. Therefore, the present research was aimed to
compare the parental childrearing styles and anxiety of children
with stuttering and normal population. It was also aimed to study
the relationship between parental child rearing styles and anxiety
of children. The research sample included 54 boys with stuttering
and 54 normal boys who were selected from the children (boys) of
Tehran, Iran in the age range of 5 to 8 years in 2013. In order to
collect data, Baum-rind Childrearing Styles Inventory and Spence
Parental Anxiety Inventory were used. Appropriate descriptive
statistical methods and multivariate variance analysis and t test for
independent groups were used to test the study hypotheses.
Statistical data analyses demonstrated that there was a significant
difference between stuttering boys and normal boys in anxiety (t =
7.601, p< 0.01); but there was no significant difference between
stuttering boys and normal boys in parental childrearing styles (F =
0.129). There was also not found significant relationship between
parental childrearing styles and children anxiety (F = 0.135, p<
0.05). It can be concluded that the influential factors of children’s
society are parents, school, teachers, peers and media. So, parental
childrearing styles are not the only influential factors on anxiety of
children, and other factors including genetic, environment and
child experiences are effective in anxiety as well. Details are
discussed.
Abstract: Hydrothermal liquefaction (HTL) is a technique for obtaining clean biofuel from biomass in the presence of heat and pressure in an aqueous medium which leads to a decomposition of this biomass to the formation of various products. A role of operating conditions is essential for the bio-oil and other products’ yield and also quality of the products. The effects of these parameters were investigated in regards to the composition and yield of the products. Chlorellaceae microalgae were tested under different HTL conditions to clarify suitable conditions for extracting bio-oil together with value-added co-products. Firstly, different microalgae loading rates (5-30%) were tested and found that this parameter has not much significant to product yield. Therefore, 10% microalgae loading rate was selected as a proper economical solution for conditioned schedule at 250oC and 30 min-reaction time. Next, a range of temperature (210-290oC) was applied to verify the effects of each parameter by keeping the reaction time constant at 30 min. The results showed no linkage with the increase of the reaction temperature and some reactions occurred that lead to different product yields. Moreover, some nutrients found in the aqueous product are possible to be utilized for nutrient recovery.
Abstract: Lignocellolusic material is a substance that is resistant to be degraded by microorganisms or hydrolysis enzymes. To be used as materials for biofuel production, it needs pretreatment process to improve efficiency of hydrolysis. In this work, chemical pretreatments on rice straw using three diluted organic acids, including acetic acid, citric acid, oxalic acid, were optimized. Using Response Surface Methodology (RSM), the effect of three pretreatment parameters, acid concentration, treatment time, and reaction temperature, on pretreatment efficiency were statistically evaluated. The results indicated that dilute oxalic acid pretreatment led to the highest enhancement of enzymatic saccharification by commercial cellulase and yielded sugar up to 10.67 mg/ml when using 5.04% oxalic acid at 137.11 oC for 30.01 min. Compared to other acid pretreatment by acetic acid, citric acid, and hydrochloric acid, the maximum sugar yields are 7.07, 6.30, and 8.53 mg/ml, respectively. Here, it was demonstrated that organic acids can be used for pretreatment of lignocellulosic materials to enhance of hydrolysis process, which could be integrated to other applications for various biorefinery processes.
Abstract: Rice straw is lignocellulosic biomass which can be utilized as substrate for the biogas production. However, due to the property and composition of rice straw, it is difficult to be degraded by hydrolysis enzymes. One of the pretreatment methods that modify such properties of lignocellulosic biomass is the application of lignocellulose-degrading microbial consortia. The aim of this study is to investigate the effect of microbial consortia to enhance biogas production. To select the high efficient consortium, cellulase enzymes were extracted and their activities were analyzed. The results suggested that microbial consortium culture obtained from cattle manure is the best candidate compared to decomposed wood and horse manure. A microbial consortium isolated from cattle manure was then mixed with anaerobic sludge and used as inoculum for biogas production. The optimal conditions for biogas production were investigated using response surface methodology (RSM). The tested parameters were the ratio of amount of microbial consortium isolated and amount of anaerobic sludge (MI:AS), substrate to inoculum ratio (S:I) and temperature. Here, the value of the regression coefficient R2 = 0.7661 could be explained by the model which is high to advocate the significance of the model. The highest cumulative biogas yield was 104.6 ml/g-rice straw at optimum ratio of MI:AS, ratio of S:I, and temperature of 2.5:1, 15:1 and 44°C respectively.
Abstract: The distribution of a single global clock across a chip
has become the major design bottleneck for high performance VLSI
systems owing to the power dissipation, process variability and multicycle
cross-chip signaling. A Network-on-Chip (NoC) architecture
partitioned into several synchronous blocks has become a promising
approach for attaining fine-grain power management at the system
level. In a NoC architecture the communication between the blocks is
handled asynchronously. To interface these blocks on a chip
operating at different frequencies, an asynchronous FIFO interface is
inevitable. However, these asynchronous FIFOs are not required if
adjacent blocks belong to the same clock domain. In this paper, we
have designed and analyzed a 16-bit asynchronous micropipelined
FIFO of depth four, with the awareness of place and route on an
FPGA device. We have used a commercially available Spartan 3
device and designed a high speed implementation of the
asynchronous 4-phase micropipeline. The asynchronous FIFO
implemented on the FPGA device shows 76 Mb/s throughput and a
handshake cycle of 109 ns for write and 101.3 ns for read at the
simulation under the worst case operating conditions (voltage =
0.95V) on a working chip at the room temperature.
Abstract: The present work attempts to investigate the
combustion, performance and emission characteristics of an existing
single-cylinder four-stroke compression-ignition engine operated in
dual-fuel mode with hydrogen as an alternative fuel. Environmental
concerns and limited amount of petroleum fuels have caused interests
in the development of alternative fuels like hydrogen for internal
combustion (IC) engines. In this experimental investigation, a diesel
engine is made to run using hydrogen in dual fuel mode with diesel,
where hydrogen is introduced into the intake manifold using an LPGCNG
injector and pilot diesel is injected using diesel injectors. A
Timed Manifold Injection (TMI) system has been developed to vary
the injection strategies. The optimized timing for the injection of
hydrogen was 10^0 CA after top dead center (ATDC). From the study
it was observed that with increasing hydrogen rate, enhancement in
brake thermal efficiency (BTHE) of the engine has been observed
with reduction in brake specific energy consumption (BSEC).
Furthermore, Soot contents decrease with an increase in indicated
specific NOx emissions with the enhancement of hydrogen flow rate.
Abstract: This work proposes a data-driven multiscale based
quantitative measures to reveal the underlying complexity of
electroencephalogram (EEG), applying to a rodent model of
hypoxic-ischemic brain injury and recovery. Motivated by that real
EEG recording is nonlinear and non-stationary over different
frequencies or scales, there is a need of more suitable approach over
the conventional single scale based tools for analyzing the EEG data.
Here, we present a new framework of complexity measures
considering changing dynamics over multiple oscillatory scales. The
proposed multiscale complexity is obtained by calculating entropies of
the probability distributions of the intrinsic mode functions extracted
by the empirical mode decomposition (EMD) of EEG. To quantify
EEG recording of a rat model of hypoxic-ischemic brain injury
following cardiac arrest, the multiscale version of Tsallis entropy is
examined. To validate the proposed complexity measure, actual EEG
recordings from rats (n=9) experiencing 7 min cardiac arrest followed
by resuscitation were analyzed. Experimental results demonstrate that
the use of the multiscale Tsallis entropy leads to better discrimination
of the injury levels and improved correlations with the neurological
deficit evaluation after 72 hours after cardiac arrest, thus suggesting an
effective metric as a prognostic tool.
Abstract: The paper presents a new method for efficient
innovation process management. Even though the innovation
management methods, tools and knowledge are well established and
documented in literature, most of the companies still do not manage it
efficiently. Especially in SMEs the front end of innovation - problem
identification, idea creation and selection - is often not optimally
performed. Our eMIPS methodology represents a sort of "umbrella
methodology" - a well-defined set of procedures, which can be
dynamically adapted to the concrete case in a company. In daily
practice, various methods (e.g. for problem identification and idea
creation) can be applied, depending on the company's needs. It is
based on the proactive involvement of the company's employees
supported by the appropriate methodology and external experts. The
presented phases are performed via a mixture of face-to-face
activities (workshops) and online (eLearning) activities taking place
in eLearning Moodle environment and using other e-communication
channels. One part of the outcomes is an identified set of
opportunities and concrete solutions ready for implementation. The
other also very important result is connected to innovation
competences for the participating employees related with concrete
tools and methods for idea management. In addition, the employees
get a strong experience for dynamic, efficient and solution oriented
managing of the invention process. The eMIPS also represents a way
of establishing or improving the innovation culture in the
organization. The first results in a pilot company showed excellent
results regarding the motivation of participants and also as to the
results achieved.
Abstract: This paper presents effects of the mean operating
pressure on the optimal operating frequency based on temperature
differences across stack ends in a thermoacoustic refrigerator. In
addition to the length of the resonance tube, components of the
thermoacoustic refrigerator have an influence on the operating
frequency due to their acoustic properties, i.e., absorptivity,
reflectivity and transmissivity. The interference of waves incurs and
distorts the original frequency generated by the driver so that the
optimal operating frequency differs from the designs. These acoustic
properties are not parameters in the designs and be very complicated
to infer their responses. A prototype thermoacoustic refrigerator is
constructed and used to investigate its optimal operating frequency
compared to the design at various operating pressures. Helium and air
are used as working fluids during the experiments. The results
indicate that the optimal operating frequency of the prototype
thermoacoustic refrigerator using helium is at 6 bar and 490Hz or
approximately 20% away from the design frequency. The optimal
operating frequency at other mean pressures differs from the design
in an unpredictable manner, however, the optimal operating
frequency and pressure can be identified by testing.
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: Honeys are produced by Apis mellifera and stingless
bees (Meliponini) in Ecuador. We studied honey produced in
beeswax combs by Apis mellifera, and honey produced in pots by
Geotrigona and Scaptotrigona bees. Chloroform extracts of honey
were obtained for fast NMR spectra. The 1D spectra were acquired at
298 K, with a 600 MHz NMR Bruker instrument, using a modified
double pulsed field gradient spin echoes (DPFGSE) sequence.
Signals of 1H NMR spectra were integrated and used as inputs for
PCA, PLS-DA analysis, and labelled sets of classes were successfully
identified, enhancing the separation between the three groups of
honey according to the entomological origin: A. mellifera,
Geotrigona and Scaptotrigona. This procedure is therefore
recommended for authenticity test of honey in Ecuador.
Abstract: In this research the effect of moisture at three levels
(47, 57, and 67 w.b.%) on the physical properties of the Pofaki pea
variety including, dimensions, geometric mean diameter, volume,
sphericity index and the surface area was determined. The influence
of different moisture levels (47, 57 and 67 w.b.%), in two loading
orientation (longitudinal and transverse) and three loading speed (4,6
and 8 mm min-1) on the mechanical properties of pea such as
maximum deformation, rupture force, rupture energy, toughness and
the power to break the pea was investigated. It was observed in the
physical properties that moisture changes were affective at 1% on,
dimensions, geometric mean diameter, volume, sphericity index and
the surface area. It was observed in the mechanical properties that
moisture changes were effective at 1% on, maximum deformation,
rupture force, rupture energy, toughness and the power to break.
Loading speed was effective on maximum deformation, rupture
force, rupture energy at 1% and it was effective on toughness at 5%.
Loading orientation was effective on maximum deformation, rupture
force, rupture energy, toughness at 1% and it was effective on power
at 5%. The mutual effect of speed and orientation were effective on
rupture energy at 1% and were effective on toughness at 5%
probability. The mutual effect of moisture and speed were effective
on rupture force and rupture energy at 1% and were effective on
toughness 5% probability. The mutual effect of orientation and
moisture on rupture energy and toughness were effective at 1%.
Abstract: The paper is focused on the identification of limiting
environmental factors of individual industrial floors on which newly
developed polymer protection and repair systems with the use of
secondary raw materials will be used. These mainly include floors
with extreme stresses and special requirements for materials used. In
relation to the environment of a particular industrial floor, it is
necessary to ensure, for example, chemical stability, resistance to
higher temperatures, resistance to higher mechanical stress, etc. for
developed materials, which is reflected in the demands for the
developed material systems. The paper describes individual
environments and, in relation to them, also requirements for
individual components of the developed materials and for the
developed materials as a whole.
Abstract: Control of honey frauds is needed in Ecuador to
protect bee keepers and consumers because simple syrups and new
syrups with eucalyptus are sold as genuine honeys. Authenticity of
Ecuadorian commercial honeys was tested with a vortex emulsion
consisting on one volume of honey:water (1:1) dilution, and two
volumes of diethyl ether. This method allows a separation of phases
in one minute to discriminate genuine honeys that form three phase
and fake honeys that form two phases; 34 of the 42 honeys analyzed
from five provinces of Ecuador were genuine. This was confirmed
with 1H NMR spectra of honey dilutions in deuterated water with an
enhanced amino acid region with signals for proline, phenylalanine
and tyrosine. Classic quality indicators were also tested with this
method (sugars, HMF), indicators of fermentation (ethanol, acetic
acid), and residues of citric acid used in the syrup manufacture. One
of the honeys gave a false positive for genuine, being an admixture of
genuine honey with added syrup, evident for the high sucrose.
Sensory analysis was the final confirmation to recognize the honey
groups studied here, namely honey produced in combs by Apis
mellifera, fake honey, and honey produced in cerumen pots by
Geotrigona, Melipona, and Scaptotrigona. Chloroform extractions of
honey were also done to search lipophilic additives in NMR spectra.
This is a valuable contribution to protect honey consumers, and to
develop the beekeeping industry in Ecuador.
Abstract: The intrinsic contradictions of entrepreneurship
development and self-development strategies complicate the task of
reaching compliance between the state economic policy and the
company entrepreneurship policy: on the one hand, there is a
contradiction between the social and the competitive order within
economic order policy and on the other hand, the contradiction exists
between entrepreneurship strategy and entrepreneurship culture
within entrepreneurship policy.