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: A reliability-based methodology which uses structural demand hazard curves to consider the increment of the ductility demands of structures with tilting is proposed. The approach considers the effect of two orthogonal components of the ground motions as well as the influence of soil-structure interaction. The approach involves the calculation of ductility demand hazard curves for symmetric systems and, alternatively, for systems with different degrees of asymmetry. To get this objective, demand hazard curves corresponding to different global ductility demands of the systems are calculated. Next, Uniform Exceedance Rate Spectra (UERS) are developed for a specific mean annual rate of exceedance value. Ratios between UERS corresponding to asymmetric and to symmetric systems located in soft soil of the valley of Mexico are obtained. Results indicate that the ductility demands corresponding to tilted structures may be several times higher than those corresponding to symmetric structures, depending on several factors such as tilting angle and vibration period of structure and soil.
Abstract: The study discussed in this paper was conducted in an
attempt to investigate effects of different drying methods (line dry
and tumble dry) on viscose single jersey fabrics knitted with ring
yarn.
Abstract: Cortisol is essential to the regulation of the immune
system and yawning is a pathological symptom of multiple sclerosis
(MS). Electromyography activity (EMG) in the jaw muscles typically
rises when the muscles are moved and with yawning is highly
correlated with cortisol levels in healthy people. Saliva samples from
59 participants were collected at the start and after yawning, or at the
end of the presentation of yawning-provoking stimuli, in the absence
of a yawn, together with EMG data and questionnaire data: Hospital
Anxiety and Depression Scale, Yawning Susceptibility Scale,
General Health Questionnaire, demographic, health details. Exclusion
criteria: chronic fatigue, diabetes, fibromyalgia, heart condition, high
blood pressure, hormone replacement therapy, multiple sclerosis,
stroke. Significant differences were found between the saliva cortisol
samples for the yawners, t (23) = -4.263, p = 0.000, as compared with
the non-yawners between rest and post-stimuli, which was nonsignificant.
Significant evidence was found to support the Thompson
Cortisol Hypothesis suggesting that rises in cortisol levels are
associated with yawning. Further research is exploring the use of
cortisol as an early diagnostic tool for MS. Ethics approval granted
and professional code of conduct, confidentiality, and safety issues
are approved therein.
Abstract: A large amount of blast furnace slag is generated in
China. Most ground granulated blast furnace slag (GGBS) however
ends up in low-grade applications. Blast furnace slag, ground to an
appropriate fineness, can be used as a partial replacement of
cementitious material in concrete. The potential for using GGBS in
structural concrete, e.g. concrete beams and columns is investigated
at Xi’an Jiaotong-Liverpool University (XJTLU). With 50% of CEM
I cement replaced with GGBS, peak hydration temperatures
determined in a suspended concrete slab reduced by 20%. This
beneficiary effect has not been further improved with 70% of CEM I
replaced with GGBS. Partial replacement of CEM I with GGBS has a
retardation effect on the early-age strength of concrete. More GGBS
concrete mixes will be conducted to identify an ‘optimum’
replacement level which will lead to a reduced thermal loading,
without significantly compromising the early-age strength of
concrete.
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: 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: A numerical model has been developed to investigate the thermally triggered release kinetics for drug delivery using phase change material as shell of microcapsules. Biocompatible material n-Eicosane is used as demonstration. PCM shell of microcapsule will remain in solid form after the drug is taken, so the drug will be encapsulated by the shell, and will not be released until the target body part of lesion is exposed to external heat source, which will thermally trigger the release kinetics, leading to solid-to-liquid phase change. The findings can lead to better understanding on the key effects influencing the phase change process for drug delivery applications. The facile approach to release drug from core/shell structure of microcapsule can be well integrated with organic solvent free fabrication of microcapsules, using double emulsion as template in microfluidic aqueous two phase system.
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: 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: 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 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 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: The thermal performance of a solar water heating with
1.00 m2 flat plate collectors in Cascavel - PR, is which presented in
this article, paper presents the solution to leverage the marketing of
solar heating systems through detailed constituent materials of the
solar collector studies, these abundant materials in construction, such
as expanded polyethylene, PVC, aluminum and glass tubes, mixing
them with new materials to minimize loss of efficiency while
decreasing its cost. The system was tested during months and the
collector obtained maximum recorded temperature of outlet fluid of
55°C, while the maximum temperature of the water at the bottom of
the hot water tank was 35°C. The average daily energy collected was
19.6 MJ/d; the energy supplied by the solar plate was 16.2 MJ/d; the
loss in the feed pipe was 3.2 MJ/d; the solar fraction was 32.2%, the
efficiency of the collector was 45.6% and the efficiency of the system
was 37.8%.
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%.