Abstract: There are several means to measure the oxidation of edible oils, such as the acid value, the peroxide value, and the anisidine value. However, these means require large quantities of reagents and are time-consuming tasks. Therefore, a more convenient and time-saving way to measure the oxidation of edible oils is required. In this report, an edible oil condition sensor was fabricated by using single-walled nanotubes (SWNT). In order to test the sensor, oxidized edible oils, each one at a different acid value, were prepared. The SWNT sensors were immersed into these oxidized oils and the resistance changes in the sensors were measured. It was found that the conductivity of the sensors decreased as the oxidation level of oil increased. This result suggests that a change of the oil components induced by the oxidation process in edible oils is related to the conductivity change in the SWNT sensor.
Abstract: The steam cracking reactions are always accompanied with the formation of coke which deposits on the walls of the tubular reactors. The investigation has attempted to control catalytic coking by the applying aluminum, zinc and ceramic coating like aluminum-magnesium by thermal spray and pack cementation method. Rate of coke formation during steam cracking of naphtha has been investigated both for uncoated stainless steel (with different alloys) and metal coating constructed with thermal Spray and pack cementation method with metal powders of Aluminum, Aluminum-Magnesium, zinc, silicon, nickel and chromium. The results of the study show that passivating the surface of SS321 with a coating of Aluminum and Aluminum-Magnesium can significantly reduce the rate of coke deposition during naphtha pyrolysis. SEM and EDAX techniques (Philips XL Series) were used to examine the coke deposits formed by the metal-hydrocarbon reactions. Our objective was to separate the different stages by identifying the characteristic morphologies.
Abstract: Total liquid ventilation can support gas exchange in animal models of lung injury. Clinical application awaits further technical improvements and performance verification. Our aim was to develop a liquid ventilator, able to deliver accurate tidal volumes, and a computerized system for measuring lung mechanics. The computer-assisted, piston-driven respirator controlled ventilatory parameters that were displayed and modified on a real-time basis. Pressure and temperature transducers along with a lineal displacement controller provided the necessary signals to calculate lung mechanics. Ten newborn lambs (
Abstract: Ciprofloxacin (CIP) and Carbamazepine (CBZ), nonbiodegradable pharmaceutical residues, were become emerging pollutants in several aquatic environments. The objectives of this research were to study the possibility to recover these pharmaceuticals residues from pharmaceutical wastewater by increasing the selective adsorption on synthesized functionalized porous silicate, comparing with powdered activated carbon (PAC). Hexagonal mesoporous silicate (HMS), functionalized HMSs (3- aminopropyltriethoxy, 3- mercaptopropyltrimethoxy and noctyldimethyl) were synthesized and characterized physico-chemical characteristics. Obtained adsorption kinetics and isotherms showed that 3-mercaptopropyltrimethoxy functional groups grafted on HMS provided highest CIP and CBZ adsorption capacities; however, it was still lower than that of PAC. The kinetic results were compatible with pseudo-second order. The hydrophobicity and hydrogen bonding might play a key role on the adsorption. Furthermore, the capacities were affected by varying pH values due to the strength of hydrogen bonding between targeted compounds and adsorbents. Electrostatic interaction might not affect the adsorption capacities.
Abstract: Environmental contamination is a common problem in ex-industrial and industrial sites. This article gives a brief description of general applied environmental investigation methodologies and possible remediation applications in Latvia. Most of contaminated areas are situated in former and active industrial, military areas and ports. Industrial and logistic activities very often have been with great impact for more than hundred years thus the contamination level with heavy metals, hydrocarbons, pesticides, persistent organic pollutants is high and is threatening health and environment in general. 242 territories now are numbered as contaminated and fixed in the National Register of contaminated territories in Latvia. Research and remediation of contamination in densely populated areas are of important environmental policy domain. Four different investigation case studies of contaminated areas are given describing the history of use, environmental quality assessment as well as planned environmental management actions. All four case study locations are situated in Riga - the capital of the Republic of Latvia. The aim of this paper is to analyze the situation and problems with management of contaminated areas in Latvia, give description of field research methods and recommendations for remediation industry based on scientific data and innovations.
Abstract: High pressure adsorption of carbon dioxide on zeolite
13X was investigated in the pressure range (0 to 4) Mpa and
temperatures 298, 308 and 323K. The data fitting is accomplished
with the Toth, UNILAN, Dubinin-Astakhov and virial adsorption
models which are generally used for micro porous adsorbents such as
zeolites. Comparison with experimental data from the literature
indicated that the virial model would best determine results. These
results may be partly attributed to the flexibility of the virial model
which can accommodate as many constants as the data warrants.
Abstract: In the Lost Foam Casting process, melting point
temperature of metal, as well as volume and rate of the foam
degradation have significant effect on the mold filling pattern.
Therefore, gas generation capacity and gas gap length are two
important parameters for modeling of mold filling time of the lost
foam casting processes. In this paper, the gas gap length at the liquidfoam
interface for a low melting point (aluminum) alloy and a high
melting point (Carbon-steel) alloy are investigated by the
photography technique. Results of the photography technique
indicated, that the gas gap length and the mold filling time are
increased with increased coating thickness and density of the foam.
The Gas gap lengths measured in aluminum and Carbon-steel,
depend on the foam density, and were approximately 4-5 and 25-60
mm, respectively. By using a new system, the gas generation
capacity for the aluminum and steel was measured. The gas
generation capacity measurements indicated that gas generation in
the Aluminum and Carbon-steel lost foam casting was about 50 CC/g
and 3200 CC/g polystyrene, respectively.
Abstract: Theobjective of this study was to evaluate the optimal
treatment condition of Fenton oxidation process to removal
contaminant in soil slurry contaminated by petroleum hydrocarbons.
This research studied somefactors that affect the removal efficiency
of petroleum hydrocarbons in soil slurry including molar ratio of
hydrogen peroxide (H2O2) to ferrous ion(Fe2+), pH condition and
reaction time.The resultsdemonstrated that the optimum condition
was that the molar ratio of H2O2:Fe3+ was 200:1,the pHwas 4.0and
the rate of reaction was increasing rapidly from starting point to 7th
hour and destruction kinetic rate (k) was 0.24 h-1. Approximately
96% of petroleum hydrocarbon was observed(initialtotal petroleum
hydrocarbon (TPH) concentration = 70±7gkg-1)
Abstract: Borate minerals have attracted considerable attention in the past years due to their structural chemistry and mechanical properties in several industries. Recently, increasing attention has been paid to the use of; synthetically produced magnesium borates as catalysts reinforcing material for plastics, the conversion of hydrocarbons, electro-conductive treating agent, anti-wear and anti-corrosion materials. Magnesium borates can be synthesized by several methods such as; hydrothermal and solid-state (thermal) processes. In this study the hydrothermal production method was applied at the modest temperature of 80C along with convenient crystal growth. Using MgCl2.6H2O, H3BO3, and NaOH as starting materials, 30, 60, 120, 240 minutes of reaction times were studied. After all, the crystal structure and the morphology of the products were examined by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). As a result the forms of Admontite and Mcallisterite minerals were synthesized.
Abstract: There is need to explore emerging technologies based on carbon nanotube electronics as the MOS technology is approaching its limits. As MOS devices scale to the nano ranges, increased short channel effects and process variations considerably effect device and circuit designs. As a promising new transistor, the Carbon Nanotube Field Effect Transistor(CNTFET) avoids most of the fundamental limitations of the Traditional MOSFET devices. In this paper we present the analysis and comparision of a Carbon Nanotube FET(CNTFET) based 10(A current mirror with MOSFET for 32nm technology node. The comparision shows the superiority of the former in terms of 97% increase in output resistance,24% decrease in power dissipation and 40% decrease in minimum voltage required for constant saturation current. Furthermore the effect on performance of current mirror due to change in chirality vector of CNT has also been investigated. The circuit simulations are carried out using HSPICE model.
Abstract: Gas hydrates form when a number of factors co-exist:
free water, hydrocarbon gas, cold temperatures and high pressures are typical of the near mud-line conditions in a deepwater drilling
operation. Subsequently, when drilling with water based muds, particularly on exploration wells, the risk of hydrate formation
associated with a gas influx is high. The consequences of gas hydrate
formation while drilling are severe, and as such, every effort should be made to ensure the risk of hydrate formation is either eliminated
or significantly reduced. Thermodynamic inhibitors are used to reduce the free water content of a drilling mud, and thus suppress the
hydrate formation temperature. Very little experimental work has
been performed by oil and gas research companies on the evaluation
of gas hydrate formation in a water-based drilling mud. The main
objective of this paper is to investigate the experimental gas hydrate
formation for a mixture of methane, carbon dioxide & nitrogen in a
water-based drilling mud with or without presence of different
concentrations of thermodynamic inhibitors including pure salt and a
combination of salt with methanol or ethylene glycol at different
concentrations in a static loop apparatus. The experiments were
performed using a static loop apparatus consisting of a 2.4307 cm
inside diameter and 800 cm long pipe. All experiments were conducted at 2200 psia. The temperature in the loop was decreased at
a rate of 3.33 °F/h from initial temperature of 80 °F.
Abstract: This study aims to screen out and to optimize the
major nutrients for maximum carotenoid production and
antioxidation characteristics by Rhodotorula rubra. It was found that
supplementary of 10 g/l glucose as carbon source, 1 g/l ammonium
sulfate as nitrogen source and 1 g/l yeast extract as growth factor in
the medium provided the better yield of carotenoid content of 30.39
μg/g cell dry weight the amount of antioxidation of Rhodotorula
rubra by DPPH, ABTS and MDA method were 1.463%, 34.21% and
34.09 μmol/l, respectively.
Abstract: commercially produced in Malaysia granular
palm shell activated carbon (PSAC) was biomodified with
bacterial biomass (Bacillus subtilis) to produce a hybrid
biosorbent of higher efficiency. The obtained biosorbent was
evaluated in terms of adsorption capacity to remove copper
and zinc metal ions from aqueous solutions. The adsorption
capacity was evaluated in batch adsorption experiments where
concentrations of metal ions varied from 20 to 350 mg/L. A
range of pH from 3 to 6 of aqueous solutions containing metal
ions was tested. Langmuir adsorption model was used to
interpret the experimental data. Comparison of the adsorption
data of the biomodified and original palm shell activated
carbon showed higher uptake of metal ions by the hybrid
biosorbent. A trend in metal ions uptake increase with the
increase in the solution-s pH was observed. The surface
characterization data indicated a decrease in the total surface
area for the hybrid biosorbent; however the uptake of copper
and zinc by it was at least equal to the original PSAC at pH 4
and 5. The highest capacity of the hybrid biosorbent was
observed at pH 5 and comprised 22 mg/g and 19 mg/g for
copper and zinc, respectively. The adsorption capacity at the
lowest pH of 3 was significantly low. The experimental results
facilitated identification of potential factors influencing the
adsorption of copper and zinc onto biomodified and original
palm shell activated carbon.
Abstract: In most wheat growing moderate regions and
especially in the north of Iran climate, is affected grain filling by
several physical and abiotic stresses. In this region, grain filling often
occurs when temperatures are increasing and moisture supply is
decreasing. The experiment was designed in RCBD with split plot
arrangements with four replications. Four irrigation treatments
included (I0) no irrigation (check); (I1) one irrigation (50 mm) at
heading stage; (I2) two irrigation (100 mm) at heading and anthesis
stage; and (I3) three irrigation (150 mm) at heading, anthesis and
early grain filling growth stage, two wheat cultivars (Milan and
Shanghai) were cultured in the experiment. Totally raining was 453
mm during the growth season. The result indicated that biological
yield, grain yield and harvest index were significantly affected by
irrigation levels. I3 treatment produced more tillers number in m2,
fertile tillers number in m2, harvest index and biological yield. Milan
produced more tillers number in m2, fertile tillers in m2, while
Shanghai produced heavier tillers and grain 1000 weight. Plant height
was significant in wheat varieties while were not statistically
significant in irrigation levels. Milan produced more grain yield,
harvest index and biological yield. Grain yield shown that I1, I2, and
I3 produced increasing of 5228 (21%), 5460 (27%) and 5670 (29%)
kg ha-1, respectively. There was an interaction of irrigation and
cultivar on grain yields. In the absence of the irrigation reduced grain
1000 weight from 45 to 40 g. No irrigation reduced soil moisture
extraction during the grain filling stage. Current assimilation as a
source of carbon for grain filling depends on the light intercepting
viable green surfaces of the plant after anthesis that due to natural
senescence and the effect of various stresses. At the same time the
demand by the growing grain is increasing. It is concluded from
research work that wheat crop irrigated Milan cultivar could increase
the grain yield in comparison with Shanghai cultivar. Although, the
grain yield of Shanghai under irrigation was slightly lower than
Milan. This grain yield also was related to weather condition, sowing
date, plant density and location conditions and management of
fertilizers, because there was not significant difference in biological
and straw yield. The best result was produced by I1 treatment. I2 and
I3 treatments were not significantly difference with I1 treatment.
Grain yield of I1 indicated that wheat is under soil moisture
deficiency. Therefore, I1 irrigation was better than I0.
Abstract: The pollution of sediments sampled from the North
Port by polycyclic aromatic hydrocarbons (PAHs) was investigated.
Concentrations of PAHs estimated in the port sediments ranged from
199 to 2851.2 μg/kg dw. The highest concentration was found which
is closed to the Berth line, this locations affected by intensive
shipping activities and Land based runoff and they were dominated
by the high molecular weight PAHs (4–6- rings). Source
identification showed that PAHs originated mostly from the
pyrogenic source either from the combustion of fossil fuels, grass,
wood and coal (majority of the samples). Ecological Risk Assessment
on the port sediments presented that slightly adverse ecological
effects to biological community are expected to occur at the vicinity
of the stations 1 and 4. Thus PAHs are not considered as pollutants of
concern in the North Port.
Abstract: Sarkhoon gas plant, located in south of Iran, has been installed to removal H2S contained in a high pressure natural gas stream. The solvent used for the H2S removal from gaseous stream is 34% by weight (wt%) Di-ethanol amine (DEA) solutions. Due to increasing concentration of heat stable salt (HSS) in solvent, corrosivity of amine solution had been increased. Reports indicated that there was corrosion on the shell of regeneration column. Because source formation of HSS was unknown, we decided to control the amount of HSS at the limit less than 3% wt amine solvent. Therefore, two small columns were filled by strong anionic base and carbon active, and then polluted amine was passed through beds. Finally a temporary amine recovery package on industrial scale was made based on laboratory’s results. From economical point of view we could save $700000 beside corrosion occurrence of the stripping column has been vigorously decreased.
Abstract: In this study, multiwall carbon nanotubes (MWNTs)
were modified with nitric acid chemically and by dielectric barrier
discharge (DBD) plasma in an oxygen-based atmosphere. Used
carbon nanotubes (CNTs) were prepared by chemical vapour
deposition (CVD) floating catalyst method. For removing amorphous
carbon and metal catalyst, MWNTs were exposed to dry air and
washed with hydrochloric acid. Heating purified CNTs under helium
atmosphere caused elimination of acidic functional groups. Fourier
transformed infrared spectroscopy (FTIR) shows formation of
oxygen containing groups such as C=O and COOH. Brunauer,
Emmett, Teller (BET) analysis revealed that functionalization causes
generation of defects on the sidewalls and opening of the ends of
CNTs. Results of temperature-programmed desorption (TPD) and gas
chromatography(GC) indicate that nitric acid treatment create more
acidic groups than plasma treatment.
Abstract: Pabdeh shaly formation (Paleocene-Oligomiocene)
has been expanded in Fars, Khozestan and Lorestan. The lower
lithostratigraphic limit of this formation in Shiraz area is
distinguished from Gurpi formation by purple shale. Its upper limit is
gradational and conformable with Asmari formation. In order to
study sequence stratigraphy and microfacies of Pabdeh formation in
Shiraz area, one stratigraphic section have been chosen (Zanjiran
section). Petrographic studies resulted in the identification of 9
pelagic and calciturbidite microfacies. The calciturbidite microfacies
have been formed when the sea level was high, the rate of carbonate
deposition was high and it slumped into the deep marine. Sequence
stratigraphy studies show that Pabdeh formation in the studied zone
consists of two depositional sequences (DS) that the lower contact is
erosional (purple shale - type one, SBI or type two, SB2) and the
upper contact is correlative conformity (type two, SB2).
Abstract: The rangelands, as one of the largest dynamic biomes
in the world, have very capabilities. Regulation of greenhouse gases
in the Earth's atmosphere, particularly carbon dioxide as the main
these gases, is one of these cases. The attention to rangeland, as
cheep and reachable resources to sequestrate the carbon dioxide,
increases after the Industrial Revolution. Rangelands comprise the
large parts of Iran as a steppic area. Rudshur (Saveh), as area index of
steppic area, was selected under three sites include long-term
exclosure, medium-term exclosure, and grazable area in order to the
capable of carbon dioxide’s sequestration of dominated species.
Canopy cover’s percentage of two dominated species (Artemisia
sieberi Besser & Stipa barbata Desf) was determined via establishing
of random 1 square meter plot. The sampling of above and below
ground biomass style was obtained by complete random. After
determination of ash percentage in the laboratory; conversion ratio of
plant biomass to organic carbon was calculated by ignition method.
Results of the paired t-test showed that the amount of carbon
sequestration in above ground and underground biomass of Artemisia
sieberi Besser & Stipa barbata Desf is different in three regions. It,
of course, hasn’t any difference between under and surface ground’s
biomass of Artemisia sieberi Besser in long-term exclosure. The
independent t-test results indicate differences between underground
biomass corresponding each other in the studied sites. Carbon
sequestration in the Stipa barbata Desf was totally more than
Artemisia sieberi Besser. Altogether, the average sequestration of the
long-term exclosure was 5.842gr/m², the medium-term exclosure was
4.115gr/m², and grazable area was 5.975gr/m² so that there isn’t
valuable statistical difference in term of total amount of carbon
sequestration to three sites.
Abstract: The aim of this study was to screen for
microorganism that able to utilize 3-N-trimethylamino-1-propanol
(homocholine) as a sole source of carbon and nitrogen. The aerobic
degradation of homocholine has been found by a gram-positive
Rhodococcus sp. bacterium isolated from soil. The isolate was
identified as Rhodococcus sp. strain A4 based on the phenotypic
features, physiologic and biochemical characteristics, and
phylogenetic analysis. The cells of the isolated strain grown on both
basal-TMAP and nutrient agar medium displayed elementary
branching mycelia fragmented into irregular rod and coccoid
elements. Comparative 16S rDNA sequencing studies indicated that
the strain A4 falls into the Rhodococcus erythropolis subclade and
forms a monophyletic group with the type-strains of R. opacus, and
R. wratislaviensis. Metabolites analysis by capillary electrophoresis,
fast atom bombardment-mass spectrometry, and gas
chromatography- mass spectrometry, showed trimethylamine (TMA)
as the major metabolite beside β-alanine betaine and
trimethylaminopropionaldehyde. Therefore, the possible degradation
pathway of trimethylamino propanol in the isolated strain is through
consequence oxidation of alcohol group (-OH) to aldehyde (-CHO)
and acid (-COOH), and thereafter the cleavage of β-alanine betaine
C-N bonds yielded trimethylamine and alkyl chain.