Abstract: Microstructural and electrical properties of
Cu-chromium alloy (Cu-Cr) dispersed with vapor-grown carbon fiber
(VGCF) prepared by powder metallurgy (P/M) process have been
investigated. Cu-0.7 mass% Cr pre-alloyed powder (Cu-Cr) made by
water atomization process was used as raw materials, which contained
solid solute Cr elements in Cu matrix. The alloy powder coated with
un-bundled VGCF by using oil coating process was consolidated at
1223 K in vacuum by spark plasma sintering, and then extruded at
1073 K. The extruded Cu-Cr alloy (monolithic alloy) had 209.3 MPa
YS and 80.4 IACS% conductivity. The extruded Cu-Cr with 0.1
mass% VGCF composites revealed a small decrease of YS compared
to the monolithic Cu-Cr alloy. On the other hand, the composite had a
higher electrical conductivity than that of the monolithic alloy. For
example, Cu-Cr with 0.1 mass% VGCF composite sintered for 5 h
showed 182.7 MPa YS and 89.7 IACS% conductivity. In the case of
Cu-Cr with VGCFs composites, the Cr concentration was observed
around VGCF by SEM-EDS analysis, where Cr23C6 compounds were
detected by TEM observation. The amount of Cr solid solution in the
matrix of the Cu-Cr composites alloy was about 50% compared to the
monolithic Cu-Cr sintered alloy, and resulted in the remarkable
increment of the electrical conductivity.
Abstract: Extracting and determining chlorophyll pigments
(chlorophyll a and b) in green leaves are the procedures based on the
solvent extraction of pigments in samples using N,Ndimethylformamide
as the extractant. In this study, two species of
soluble inorganic selenium forms, selenite (SeIV) and selenate (SeVI)
at different concentrations were investigated on maize plants that
were growing in nutrient solutions during 2 weeks and at the end of
the experiment, amounts of chlorophyll a and b for first and second
leaves of maize were measured. In accordance with the results we
observed that our regarded Se concentrations in both forms of SeIV
and SeVI were not effective on maize plants’ chlorophyll a and b
significantly although high level of 3 mg.kg-1 SeIV had negative affect
on growth of the samples that had been treated by it but about SeVI
samples we did not observe this state and our different considered
SeVI concentrations were not toxic for maize plants.
Abstract: The concentrations of heavy metals in sediments of
Qua Iboe River Estuary (QIRE) were monitored at four different
sampling locations in wet and dry seasons. A preliminary survey to
determine the four sampling stations along the river continuum
showed that the area spanned between
Abstract: In this paper, we propose a system for preventing gas
risks through the use of wireless communication modules and
intelligent gas safety appliances. Our system configuration consists of
an automatic extinguishing system, detectors, a wall-pad, and a
microcomputer controlled micom gas meter to monitor gas flow and
pressure as well as the occurrence of earthquakes. The automatic fire
extinguishing system checks for both combustible gaseous leaks and
monitors the environmental temperature, while the detector array
measures smoke and CO gas concentrations. Depending on detected
conditions, the micom gas meter cuts off an inner valve and generates
a warning, the automatic fire-extinguishing system cuts off an external
valve and sprays extinguishing materials, or the sensors generate
signals and take further action when smoke or CO are detected.
Information on intelligent measures taken by the gas safety appliances
and sensors are transmitted to the wall-pad, which in turn relays this as
real time data to a server that can be monitored via an external network
(BcN) connection to a web or mobile application for the management
of gas safety. To validate this smart-home gas management system, we
field-tested its suitability for use in Korean apartments under several
scenarios.
Abstract: Phthalates are ubiquitous environmental pollutants
well known because of their endocrine disrupting activity in human
organism. The aim of our study was, by biological monitoring,
investigate exposure to phthalates of Roma ethnicity group i.e.
children and adults from 5 families (n=29, average age 11.8 ± 7.6
years) living in western Slovakia. Additionally, we analysed some
associations between anthropometric measures, questionnaire data
i.e. socio-economic status, eating and drinking habits, practise of
personal care products and household conditions in comparison with
concentrations of phthalate metabolites. We used for analysis of urine
samples high performance liquid chromatography and tandem mass
spectrometry (HPLC-MS/MS) to determine concentrations of
phthalate metabolites monoethyl phthalate (MEP), mono-n-butyl
phthalate (MnBP), mono-iso-butyl phthalate (MiBP), mono(2-ethyl-
5-hydroxyhexyl) phthalate (5OH-MEHP), mono(2-ethyl-5-oxohexyl)
phthalate (5oxo-MEHP) and mono(2-etylhexyl) phthalate (MEHP).
Our results indicate that ethnicity, lower socioeconomic status and
different housing conditions in Roma population can affect urinary
concentration of phthalate metabolites.
Abstract: The separation of Hg (II) from produced water by
hollow fiber contactors (HFC) was investigation. This system
included of two hollow fiber modules in the series connecting. The
first module used for the extraction reaction and the second module
for stripping reaction. Aliquat336 extractant was fed from the organic
reservoirs into the shell side of the first hollow fiber module and
continuous to the shell side of the second module. The organic liquid
was continuously feed recirculate and back to the reservoirs. The feed
solution was pumped into the lumen (tube side) of the first hollow
fiber module. Simultaneously, the stripping solution was pumped in
the same way in tube side of the second module. The feed and
stripping solution was fed which had a countercurrent flow. Samples
were kept in the outlet of feed and stripping solution at 1 hour and
characterized concentration of Hg (II) by Inductively Couple Plasma
Atomic Emission Spectroscopy (ICP-AES). Feed solution was
produced water from natural gulf of Thailand. The extractant was
Aliquat336 dissolved in kerosene diluent. Stripping solution used was
nitric acid (HNO3) and thiourea (NH2CSNH2). The effect of carrier
concentration and type of stripping solution were investigated.
Results showed that the best condition were 10 % (v/v) Aliquat336
and 1.0 M NH2CSNH2. At the optimum condition, the extraction and
stripping of Hg (II) were 98% and 44.2%, respectively.
Abstract: This paper analyses the heat transfer performance and
fluid flow using different nanofluids in a square enclosure. The
energy equation and Navier-Stokes equation are solved numerically
using finite volume scheme. The effect of volume fraction
concentration on the enhancement of heat transfer has been studied
icorporating the Brownian motion; the influence of effective thermal
conductivity on the enhancement was also investigated for a range of
volume fraction concentration. The velocity profile for different
Rayleigh number. Water-Cu, water AL2O3 and water-TiO2 were
tested.
Abstract: A field study was conducted to evaluate the efficacy of
safflower plant for phytoremediation of contaminated soils. The
experiment was performed on an agricultural fields contaminated by
the Non-Ferrous-Metal Works near Plovdiv, Bulgaria. Field
experiments with randomized complete block design with five
treatments (control, compost amendments added at 20 and 40 t/daa,
and vermicompost amendments added at 20 and 40 t/daa) were
carried out. The quality of safflower seeds and oil (heavy metals and
fatty acid composition) were determined. Tested organic amendments
significantly influenced the chemical composition of safflower seeds
and oil. The compost and vermicompost treatments significantly
reduced heavy metals concentration in safflower seeds and oils, but
the effect differed among them. Addition of vermicompost and
compost leads to an increase in the content of palmitic acid and
linoleic acid, and a decrease in the stearic and oleic acids compared
with the control. A significant increase in the quantity of saturated
acids was observed in the variants with 20 t/daa of compost and 20
t/daa of vermicompost (9.1 and 8.9% relative to the control).
Safflower is a plant which is tolerant to heavy metals and can be
successfully used in the phytoremediation of heavy metal
contaminated soils. The processing of seeds to oil and using the
obtained oil for nutritional purposes will greatly reduce the cost of
phytoremediation.
Abstract: This work studied the isomerization of 1-butene over
hydrotalcite catalyst. The experiments were conducted at various gas
hourly space velocity (GHSV), reaction temperature and feed
concentration. No catalyst deactivation was observed over the
reaction time of 16 hours. Two major reaction products were trans-2-
butene and cis-2-butene. The reaction temperature played an
important role on the reaction selectivity. At high operating
temperatures, the selectivity of trans-2-butene was higher than the
selectivity of cis-2-butene while it was opposite at lower reaction
temperature. In the range of operating condition, the maximum
conversion of 1-butene was found at 74% when T = 673 K and GHSV
= 4 m3/h/kg-cat with trans- and cis-2-butene selectivities of 54% and
46%, respectively. Finally, the kinetic parameters of the reaction
were determined.
Abstract: The atmospheres in many cities along the coastal lines
in the world have been rapidly changed to coastal-industrial
atmosphere. Hence, it is vital to investigate the corrosion behavior of
steel exposed to this kind of environment. In this present study,
Electrochemical Impedance Spectrography (EIS) and film thickness
measurement were applied to monitor the corrosion behavior of
weathering steel covered with a thin layer of the electrolyte in a
wet-dry cyclic condition, simulating a coastal-industrial environment
at 25oC and 60% RH. The results indicate that in all cycles, the
corrosion rate increases during the drying process due to an increase in
anion concentration and an acceleration of oxygen diffusion enhanced
by the effect of the thinning out of the electrolyte. During the wet-dry
cyclic corrosion test, the long-term corrosion behavior of this steel
depends on the periods of exposure. Corrosion process is first
accelerated and then decelerated. The decelerating corrosion process is
contributed to the formation of the protective rust, favored by the
wet-dry cycle and the acid regeneration process during the rusting
process.
Abstract: Prosperity of electronic equipment in photocopying
environment not only has improved work efficiency, but also has
changed indoor air quality. Considering the number of photocopying
employed, indoor air quality might be worse than in general office
environments. Determining the contribution from any type of
equipment to indoor air pollution is a complex matter. Non-methane
hydrocarbons are known to have an important role on air quality due
to their high reactivity. The presence of hazardous pollutants in
indoor air has been detected in one photocopying shop in Novi Sad,
Serbia. Air samples were collected and analyzed for five days, during
8-hr working time in three time intervals, whereas three different
sampling points were determined. Using multiple linear regression
model and software package STATISTICA 10 the concentrations of
occupational hazards and microclimates parameters were mutually
correlated. Based on the obtained multiple coefficients of
determination (0.3751, 0.2389 and 0.1975), a weak positive
correlation between the observed variables was determined. Small
values of parameter F indicated that there was no statistically
significant difference between the concentration levels of nonmethane
hydrocarbons and microclimates parameters. The results
showed that variable could be presented by the general regression
model: y = b0 + b1xi1+ b2xi2. Obtained regression equations allow to
measure the quantitative agreement between the variables and thus
obtain more accurate knowledge of their mutual relations.
Abstract: In this work, two fermentations at different
temperatures (25 and 30ºC), with cell recycling, were accomplished
to produce ethanol, using a mix of commercial substrates, xylose
(70%) and glucose (30%), as organic source for Scheffersomyces
stipitis. Five consecutive fermentations of 80 g L-1 (1º, 2º and 3º
recycles), 96 g L-1 (4º recycle) and 120 g L-1 (5º recycle)reduced
sugars led to a final maximum ethanol concentration of 17.2 and 34.5
g L-1, at 25 and 30ºC, respectively. Glucose was the preferred
substrate; moreover xylose startup degradation was initiated after a
remaining glucose presence in the medium. Results showed that yeast
acid treatment, performed before each cycle, provided improvements
on cell viability, accompanied by ethanol productivity of 2.16 g L-1 h-
1 at 30ºC. A maximum 36% of xylose was retained in the
fermentation medium and after five-cycle fermentation an ethanol
yield of 0.43 g ethanol/g sugars was observed. S. stipitis fermentation
capacity and tolerance showed better results at 30ºC with 83.4% of
theoretical yield referenced on initial biomass.
Abstract: The use of engineered nanomaterials has increased as
a result of their positive impact on many sectors of the economy,
including agriculture. Silver nanoparticles (AgNPs) are now used to
enhance seed germination, plant growth, and photosynthetic quantum
efficiency and as antimicrobial agents to control plant diseases. In
this study, we examined the effect of AgNP dosage on the seed
germination of three plant species: corn (Zea mays L.), watermelon
(Citrullus lanatus [Thunb.] Matsum. & Nakai) and zucchini
(Cucurbita pepo L.). This experiment was designed to study the
effect of AgNPs on germination percentage, germination rate, mean
germination time, root length and fresh and dry weight of seedlings
for the three species. Seven concentrations (0.05, 0.1, 0.5, 1, 1.5, 2
and 2.5 mg/ml) of AgNPs were examined at the seed germination
stage. The three species had different dose responses to AgNPs in
terms of germination parameters and the measured growth
characteristics. The germination rates of the three plants were
enhanced in response to AgNPs. Significant enhancement of the
germination percentage values was observed after treatment of the
watermelon and zucchini plants with AgNPs in comparison with
untreated seeds. AgNPs showed a toxic effect on corn root
elongation, whereas watermelon and zucchini seedling growth were
positively affected by certain concentrations of AgNPs. This study
showed that exposure to AgNPs caused both positive and negative
effects on plant growth and germination.
Abstract: We investigated the structure and electronic properties
of the compound Mg1-xBixO with varying concentrations of 0, ¼, ½,
and ¾ x bismuth in the the cesium chloride (CsCl), zinc-blende
(ZnS), nickel arsenide (NiAs) NaCl (rock-salt) and WZ (wurtzite)
phases. We calculated. The calculations were performed using the
first-principles pseudo-potential method within the framework of spin
density functional theory (DFT).
Abstract: A field study was conducted to evaluate the efficacy
of lavender for phytoremediation of contaminated soils. The
experiment was performed on an agricultural fields contaminated by
the Non-Ferrous-Metal Works near Plovdiv, Bulgaria. The
concentrations of Pb, Zn and Cd in lavender (roots, stems, leaves and
inflorescences) and in the essential oils of lavender were determined.
Lavender is a plant which is tolerant to heavy metals and can be
grown on contaminated soils, and which can be referred to the
hyperaccumulators of lead and the accumulators of cadmium and
zinc, and can be successfully used in the phytoremediation of heavy
metal contaminated soils. Favorable is also the fact that heavy metals
do not influence the development of the lavender, as well as on the
quality and quantity of the essential oil. The possibility of further
industrial processing will make lavender economically interesting
crops for farmers of phytoextraction technology.
Abstract: The strawberry tree (Arbutus unedo L.) is a small tree
or shrub from botanical Ericaceae family that grows spontaneously
nearby the Mediterranean basin and produce edible red fruits. A
traditional processed fruit application, in Mediterranean countries, is
the production of a spirit (known as aguardente de medronho, in
Portugal) obtained from the fermented fruit. The main objective of
our study was to contribute to the knowledge about the influence of
the degree of maturation of fruits in the volatile composition and
quality of arbutus spirit. The major volatiles in the three distillates
fractions (head, heart and tail) obtained from fermentation of two
different fruit maturation levels were quantified by GC-FID analysis
and ANOVA one-way was performed. Additionally, the total
antioxidant capacity and total phenolic compounds of both arbutus
fruit spirits were determined, by ABTS and Folin-Ciocalteau method,
respectively. The methanol concentration is higher (1022.39 g/hL
a.a.) in the spirit made from fruits with highest total soluble solids,
which is a value above the legal limit (1000 g/hL a.a.). Overall, our
study emphasizes, for the first time, the influence of maturation
degree of arbutus fruits in the spirit volatile composition and quality.
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: In the present work, Electrochemical Impedance
Spectrocopy (EIS) is applied to study the transport of different metal
cations through a cation-exchange membrane. This technique enables
the identification of the ionic-transport characteristics and to
distinguish between different transport mechanisms occurring at
different current density ranges. The impedance spectra are
dependent on the applied dc current density, on the type of cation and
on the concentration.
When the applied dc current density increases, the diameter of the
impedance spectra loops increases because all the components of
membrane system resistance increase. The diameter of the impedance
plots decreases in the order of Na(I), Ni(II) and Cr(III) due to the
increased interactions between the negatively charged sulfonic
groups of the membrane and the cations with greater charge. Nyquist
plots are shifted towards lower values of the real impedance, and its
diameter decreases with the increase of concentration due to the
decrease of the solution resistance.
Abstract: A total of 115 yeast strains isolated from local cassava
processing wastes were measured for crude protein content. Among
these strains, the strain MSY-2 possessed the highest protein
concentration (>3.5 mg protein/mL). By using molecular
identification tools, it was identified to be a strain of Pichia
kudriavzevii based on similarity of D1/D2 domain of 26S rDNA
region. In this study, to optimize the protein production by MSY-2
strain, Response Surface Methodology (RSM) was applied. The
tested parameters were the carbon content, nitrogen content, and
incubation time. Here, the value of regression coefficient (R2) =
0.7194 could be explained by the model which is high to support the
significance of the model. Under the optimal condition, the protein
content was produced up to 3.77 g per L of the culture and MSY-2
strain contains 66.8 g protein per 100 g of cell dry weight. These
results revealed the plausibility of applying the novel strain of yeast
in single-cell protein production.
Abstract: Coal is an important non-renewable energy source of
and can be associated with radioactive elements. In Figueira city,
Paraná state, Brazil, it was recorded high uranium activity near the
coal mine that supplies a local thermoelectric power plant. In this
context, the radon activity (Rn-222, produced by the Ra-226 decay in
the U-238 natural series) was evaluated in groundwater, river water
and effluents produced from the acid mine drainage in the coal reject
dumps. The samples were collected in August 2013 and in February
2014 and analyzed at LABIDRO (Laboratory of Isotope and
Hydrochemistry), UNESP, Rio Claro city, Brazil, using an alpha
spectrometer (AlphaGuard) adjusted to evaluate the mean radon
activity concentration in five cycles of 10 minutes. No radon activity
concentration above 100 Bq.L-1, which was a previous critic value
established by the World Health Organization. The average radon
activity concentration in groundwater was higher than in surface
water and in effluent samples, possibly due to the accumulation of
uranium and radium in the aquifer layers that favors the radon
trapping. The lower value in the river waters can indicate dilution and
the intermediate value in the effluents may indicate radon absorption
in the coal particles of the reject dumps. The results also indicate that
the radon activities in the effluents increase with the sample
acidification, possibly due to the higher radium leaching and the
subsequent radon transport to the drainage flow. The water samples
of Laranjinha River and Ribeirão das Pedras stream, which,
respectively, supply Figueira city and receive the mining effluent,
exhibited higher pH values upstream the mine, reflecting the acid
mine drainage discharge. The radionuclides transport indicates the
importance of monitoring their activity concentration in natural
waters due to the risks that the radioactivity can represent to human
health.