Abstract: The purpose of the study was to determine the amount of Palm Kernel Oil (PKO) extracted from a packed bed of palm kernels in a supercritical fluid extractor using supercritical carbon dioxide (SC-CO2) as an environmental friendly solvent. Further, the study sought to ascertain the values of the overall mass transfer coefficient (K) of PKO evaluation through a mass transfer model, at constant temperature of 50 °C, 60 °C, and 70 °C and pressures range from 27.6 MPa, 34.5 MPa, 41.4 MPa and 48.3 MPa respectively. Finally, the study also seeks to demonstrate the application of the overall mass transfer coefficient values in relation to temperature and pressure. The overall mass transfer coefficient was found to be dependent pressure at each constant temperature of 50 °C, 60 °C and 70 °C. The overall mass transfer coefficient for PKO in a packed bed of palm kernels was found to be in the range of 1.21X 10-4 m min-1 to 1.72 X 10-4 m min-1 for a constant temperature of 50 °C and in the range of 2.02 X 10-4 m min-1 to 2.43 X 10-4 m min-1 for a constant temperature of 60 °C. Similar increasing trend of the overall mass transfer coefficient from 1.77 X 10-4 m min-1 to 3.64 X 10-4 m min-1 was also observed at constant temperature of 70 °C within the same pressure range from 27.6 MPa to 48.3 MPa.
Abstract: Most of ignition delay correlations studies have been
developed in a constant volume bombs which cannot capture the
dynamic variation in pressure and temperature during the ignition
delay as in real engines. Watson, Assanis et. al. and Hardenberg
and Hase correlations have been developed based on experimental
data of diesel engines. However, they showed limited predictive
ability of ignition delay when compared to experimental results. The
objective of the study was to investigate the dependency of ignition
delay time on engine brake power. An experimental investigation of
the effect of automotive diesel and water diesel emulsion fuels on
ignition delay under steady state conditions of a direct injection diesel
engine was conducted. A four cylinder, direct injection naturally
aspirated diesel engine was used in this experiment over a wide range
of engine speeds and two engine loads. The ignition delay
experimental data were compared with predictions of Assanis et. al.
and Watson ignition delay correlations. The results of the
experimental investigation were then used to develop a new ignition
delay correlation. The newly developed ignition delay correlation has
shown a better agreement with the experimental data than Assanis et.
al. and Watson when using automotive diesel and water diesel
emulsion fuels especially at low to medium engine speeds at both
loads. In addition, the second derivative of cylinder pressure which is
the most widely used method in determining the start of combustion
was investigated.
Abstract: Dehydration of methanol to dimethyl ether (DME)
over a commercial Al2O3 catalyst was studied in an isothermal integral
fixed bed reactor. The experiments were performed on the temperature
interval 513-613 K, liquid hourly space velocity (LHSV) of 0.9-2.1h-1,
pressures between 0.1 and 1.0 MPa. The effect of different operation
conditions on the dehydration of methanol was investigated in a
laboratory scale experiment. A new intrinsic kinetics equation based
on the mechanism of Langmuir-Hinshelwood dissociation adsorption
was developed for the dehydration reaction by fitting the expressions
to the experimental data. An activation energy of 67.21 kJ/mol was
obtained for the catalyst with the best performance. Statistic test
showed that this new intrinsic kinetics equation was acceptable.
Abstract: Curing of paints by exposure to UV radiations is
emerging as one of the best film forming technique as an alternative
to traditional solvent borne oxidative and thermal curing coatings.
The composition and chemistry of UV curable coatings and role of
multifunctional and monofunctional monomers, oligomers, and
photoinitiators have been discussed. The limitations imposed by
thermodynamic equilibrium and tendency for acrylic double bond
polymerizations during synthesis of multifunctional acrylates have
been presented. Aim of present investigation was thus to explore the
reaction variables associated with synthesis of multifunctional
acrylates. Zirconium oxychloride was evaluated as catalyst against
regular acid functional catalyst. The catalyzed synthesis of glyceryl
acrylate and neopentyl glycol acrylate was conducted by variation of
following reaction parameters: two different reactant molar ratios-
1:4 and 1:6; catalyst usage in % by moles on polyol- 2.5, 5.0 and 7.5
and two different reaction temperatures- 45 and 75 0C. The reaction
was monitored by determination of acid value and hydroxy value at
regular intervals, besides TLC, HPLC, and FTIR analysis of
intermediates and products. On the basis of determination of reaction
progress over 1-60 hrs, the esterification reaction was observed to
follow 2nd order kinetics with rate constant varying from 1*10-4 to
7*10-4. The thermal and catalytic components of second order rate
constant and energy of activation were also determined. Uses of
these kinetic and thermodynamic parameters in design of reactor for
manufacture of multifunctional acrylate ester have been presented.
The synthesized multifunctional acrylates were used to formulate and
apply UV curable clear coat followed by determination of curing
characteristics and mechanical properties of cured film. The overall
curing rates less than 05 min. were easily attained indicating
economical viability of radiation curable system due to faster
production schedules
Abstract: IFP Group Technology “Sulfrex process" was used in
Iran-s South Pars Gas Complex Refineries for removing sulfur
compounds such as mercaptans, carbonyl sulfide and hydrogen
sulfide, which uses sulfonated cobalt phthalocyanine dispersed in
alkaline solution as catalyst. In this technology, catalyst and alkaline
solution were used circularly. However the stability of catalyst due to
effect of some parameters would reduce with the running of the unit
and therefore sweetening efficiency would be decreased. Hence, the
aim of this research is study the factors effecting on the stability of
catalyst.
Abstract: In this work, biohydrogen production via dark
fermentation from alcohol wastewater using upflow anaerobic sludge
blanket reactors (UASB) with a working volume of 4 L was
investigated to find the optimum conditions for a maximum hydrogen
yield. The system was operated at different COD loading rates (23,
31, 46 and 62 kg/m3d) at mesophilic temperature (37 ºC) and pH 5.5.
The seed sludge was pretreated before being fed to the UASB system
by boiling at 95 ºC for 15 min. When the system was operated under
the optimum COD loading rate of 46 kg/m3d, it provided the
hydrogen content of 27%, hydrogen yield of 125.1 ml H2/g COD
removed and 95.1 ml H2/g COD applied, hydrogen production rate of
18 l/d, specific hydrogen production rate of 1080 ml H2/g MLVSS d
and 1430 ml H2/ L d, and COD removal of 24%.
Abstract: Density functional theory (DFT) calculations were performed to calculate aluminum-27, boron-11, and nitrogen-14 quadrupole coupling constant (CQ) in the representative considered model of (6, 0) boron nitride-aluminum nitride nanotube junction (BN-AlNNT) for the first time. To this aim, 1.3 nm length of BNAlN consisting of 18 Al, 18 B, and 36 N atoms was selected where the end atoms capped by hydrogen atoms. The calculated CQ values for optimized BN-AlNNT system reveal different electrostatic environment in the mentioned system. The calculations were performed using the Gaussian 98 package of program.
Abstract: CO2 is the primary anthropogenic greenhouse gas,
accounting for 77% of the human contribution to the greenhouse
effect in 2004. In the recent years, global concentration of CO2 in the
atmosphere is increasing rapidly. CO2 emissions have an impact on
global climate change. Anthropogenic CO2 is emitted primarily from
fossil fuel combustion. Carbon capture and storage (CCS) is one
option for reducing CO2 emissions. There are three major approaches
for CCS: post-combustion capture, pre-combustion capture and
oxyfuel process. Post-combustion capture offers some advantages as
existing combustion technologies can still be used without radical
changes on them.
There are several post combustion gas separation and capture
technologies being investigated, namely; (a) absorption, (b)
cryogenic separation, (c) membrane separation (d) micro algal biofixation
and (e) adsorption. Apart from establishing new techniques,
the exploration of capture materials with high separation performance
and low capital cost are paramount importance. However, the
application of adsorption from either technology, require easily
regenerable and durable adsorbents with a high CO2 adsorption
capacity. It has recently been reported that the cost of the CO2
capture can be reduced by using this technology. In this paper, the
research progress (from experimental results) in adsorbents for CO2
adsorption, storage, and separations were reviewed and future
research directions were suggested as well.
Abstract: Visfatin and apelin are two new adipokines that recently gained a special interest in diabetes research. This study was conducted to study the interplay between these two adipokines and their correlation with other inflammatory and biochemical parameters in type 2 diabetic (T2D) postmenopausal women with CAD. Visfatin and apelin were measured by enzyme-linked immunoassay (ELISA). Visfatin was found to be significantly higher in the following groups: T2D patients without CAD, non-obese and obese T2D patients with CAD when compared to control group. Apelin was found to be significantly lower in non-obese and obese T2D patients with CAD when compared to control group. Visfatin and apelin were found to be significantly associated with each other and with other biochemical parameters. The current study provides evidence for the interplay between visfatin and apelin through the inflammatory milieu characteristic of T2D and their possible role in the pathogenesis of CAD complication of T2D.
Abstract: High purity hydrogen and the valuable by-product of carbon nanotubes (CNTs) can be produced by the methane catalytic decomposition. The methane conversion and the performance of CNTs were determined by the choices of catalysts and the condition of decomposition reaction. In this paper, Ni/MgO and Ni/O-D (oxidized diamond) catalysts were prepared by wetness impregnation method. The effects of reaction temperature and space velocity of methane on the methane conversion were investigated in a fixed-bed. The surface area, structure and micrography were characterized with BET, XPS, SEM, EDS technology. The results showed that the conversion of methane was above 8% within 150 min (T=500) for 33Ni/O-D catalyst and higher than 25% within 120 min (T=650) for 41Ni/MgO catalyst. The initial conversion increased with the increasing temperature of the decomposition reaction, but their catalytic activities decreased rapidly while at too higher temperature. To decrease the space velocity of methane was propitious to promote the methane conversion, but not favor of the hydrogen yields. The appearance of carbon resulted from the methane decomposition lied on the support type and the condition of catalytic reaction. It presented as fiber shape on the surface of Ni/O-D at the relatively lower temperature such as 500 and 550, but as grain shape stacked on and overlayed on the surface of the metal nickel while at 650. The carbon fiber can form on the Ni/MgO surface at 650 and the diameter of the carbon fiber increased with the decreasing space velocity.
Abstract: The degradation of selected pharmaceuticals in some
water matrices was studied by using several chemical treatments. The
pharmaceuticals selected were the beta-blocker metoprolol, the
nonsteroidal anti-inflammatory naproxen, the antibiotic amoxicillin,
and the analgesic phenacetin; and their degradations were conducted
by using UV radiation alone, ozone, Fenton-s reagent, Fenton-like
system, photo-Fenton system, and combinations of UV radiation and
ozone with H2O2, TiO2, Fe(II), and Fe(III). The water matrices, in
addition to ultra-pure water, were a reservoir water, a groundwater,
and two secondary effluents from two municipal WWTP. The results
reveal that the presence of any second oxidant enhanced the
oxidation rates, with the systems UV/TiO2 and O3/TiO2 providing the
highest degradation rates. It is also observed in most of the
investigated oxidation systems that the degradation rate followed the
sequence: amoxicillin > naproxen > metoprolol > phenacetin. Lower
rates were obtained with the pharmaceuticals dissolved in natural
waters and secondary effluents due to the organic matter present
which consume some amounts of the oxidant agents.
Abstract: In a pilot plant scale of a fluidized bed reactor, a
reduction reaction of sodium sulfate by natural gas has been
investigated. Natural gas is applied in this study as a reductant. Feed
density, feed mass flow rate, natural gas and air flow rate
(independent parameters)and temperature of bed and CO
concentration in inlet and outlet of reactor (dependent parameters)
were monitored and recorded at steady state. The residence time was
adjusted close to value of traditional reaction [1]. An artificial neural
network (ANN) was established to study dependency of yield and
carbon gradient on operating parameters. Resultant 97% accuracy of
applied ANN is a good prove that natural gas can be used as a
reducing agent. Predicted ANN model for relation between other
sources carbon gradient (accuracy 74%) indicates there is not a
meaningful relation between other sources carbon variation and
reduction process which means carbon in granule does not have
significant effect on the reaction yield.
Abstract: The field of polymeric biomaterials is very important
from the socio-economical viewpoint. Synthetic carbohydrate
polymers are being increasingly investigated as biodegradable,
biocompatible and biorenewable materials. The aim of this study was
to synthesize and characterize some derivatives based on D-mannose.
D-mannose was chemically modified to obtain 1-O-allyl-2,3:5,6-di-
O-isopropylidene-D-mannofuranose and 1-O-(2-,3--epoxy-propyl)-
2,3:5,6-di-O-isopropylidene-D-mannofuranose.
The chemical structure of the resulting compounds was
characterized by FT-IR and NMR spectroscopy, and by HPLC-MS.
Abstract: Efficient and safe plant operation can only be
achieved if the operators are able to monitor all key process
parameters. Instrumentation is used to measure many process
variables, like temperatures, pressures, flow rates, compositions or
other product properties. Therefore Performance monitoring is a
suitable tool for operators. In this paper, we integrate rigorous
simulation model, data reconciliation and parameter estimation to
monitor process equipments and determine key performance
indicator (KPI) of them. The applied method here has been
implemented in two case studies.
Abstract: A local wastewater treatment plant (WWTP)
experiencing poor nitrification tracked down high level of
surfactants in the plant-s influent and effluent. The aims of this project were to assess the potential inhibitory effect of surfactants on activated sludge processes. The effect of the
presence of TergitolNP-9, TrigetolNP-7, Trigetol15-S-9,
dodecylbenzene sulphonate (SDBS) and sodium dodecyl
sulfate (SDS) on activated sludge oxygen uptake rate (OUR) and nitrification were assessed. The average concentration of non-ionic and anionic
surfactants in the influent to the local WWTP were 7 and 8.7 mg/L, respectively. Removal of 67% to 90% of the non-ionic and 93-99% of the anionic surfactants tested were measured. All surfactants tested showed inhibitory effects both on OUR
and nitrification. SDS incurred the lowest inhibition whereas
SDBS and NP-9 caused severe inhibition to OUR and
Nitrification. Activated sludge flocs sizes slightly decreased
after 3 hours contact with the surfactant present in the test.
The results obtained indicated that high concentrations of
surfactants are likely to have an adverse effect on the
performance of WWTPs utilizing activated sludge processes.
Abstract: Sugarcane bagasses are one of the most extensively used agricultural residues. Using acid hydrolysis and fermentation, conversion of sugarcane bagasses to lactic acid was technically and economically feasible. This research was concerned with the solubility of lignin in ammonium hydroxide, acid hydrolysis and lactic acid fermentation by Lactococcus lactis, Lactobacillus delbrueckii, Lactobacillus plantarum, and Lactobacillus casei. The lignin extraction results for different ammonium hydroxide concentrations showed that 10 % (v/v) NH4OH was favorable to lignin dissolution. Acid hydrolysis can be enhanced with increasing acid concentration and reaction temperature. The optimum glucose and xylose concentrations occurred at 121 ○C for 1 hour hydrolysis time in 10% sulphuric acid solution were 32 and 11 g/l, respectively. In order to investigate the significance of medium composition on lactic acid production, experiments were undertaken whereby a culture of Lactococcus lactis was grown under various glucose, peptone, yeast extract and xylose concentrations. The optimum medium was composed of 5 g/l glucose, 2.5 g/l xylose, 10 g/l peptone and 5 g/l yeast extract. Lactococcus lactis represents the most efficient for lactic acid production amongst those considered. The lactic acid fermentation by Lactococcus lactis after 72 hours gave the highest yield of 1.4 (g lactic acid per g reducing sugar).
Abstract: Due to the low heavy metal concentrations, the
bottom ash from a 32 MW municipal district heating plant was
determined to be a potential forest fertilizer as such. However,
additional Ca would be needed, because its Ca concentration of 1.9-
% (d.w.) was lower than the statutory Finnish minimum limit value
of 6.0-% (d.w.) for Ca in forest fertilizer. Due to the elevated As
concentration (53.0 mg/kg; d.w.) in the fly ash from the 32 MW
municipal district heating plant, and Cr concentration (620 mg/kg;
d.w.) in the ash fraction (i.e. mixture of the bottom ash and fly ash)
from the 6 MW municipal district heating plant, which exceed the
limit values of 30 mg/kg (d.w.) and 300 mg/kg (d.w.) for As and Cr,
respectively, these residues are not suitable as forest fertilizers.
Although these ash fractions cannot be used as a forest fertilizer as
such, they can be used for the landscaping of landfills or in industrial
and other areas that are closed to the public. However, an
environmental permit is then needed.
Abstract: In the process of polyethylene extrusion polymer
material similar to powder or granule is under compression, melting
and transmission operation and on base of special form, extrudate has
been produced. Twin-screw extruders are applicable in industries
because of their high capacity. The powder mixing with chemical
additives and melting with thermal and mechanical energy in three
zones (feed, compression and metering zone) and because of gear
pump and screw's pressure, converting to final product in latest plate.
Extruders with twin-screw and short distance between screws are
better than other types because of their high capacity and good
thermal and mechanical stress.
In this paper, process of polyethylene extrusion and various tapes
of extruders are studied. It is necessary to have an exact control on
process to producing high quality products with safe operation and
optimum energy consumption.
The granule size is depending on granulator motor speed. Results
show at constant feed rate a decrease in granule size was found whit
Increase in motor speed. Relationships between HDPE feed rate and
speed of granulator motor, main motor and gear pump are calculated
following as:
x = HDPE feed flow rate, yM = Main motor speed
yM = (-3.6076e-3) x^4+ (0.24597) x^3+ (-5.49003) x^2+ (64.22092)
x+61.66786 (1)
x = HDPE feed flow rate, yG = Gear pump speed
yG = (-2.4996e-3) x^4+ (0.18018) x^3+ (-4.22794) x^2+ (48.45536)
x+18.78880 (2)
x = HDPE feed flow rate, y = Granulator motor speed
10th Degree Polynomial Fit: y = a+bx+cx^2+dx^3... (3)
a = 1.2751, b = 282.4655, c = -165.2098,
d = 48.3106, e = -8.18715, f = 0.84997
g = -0.056094, h = 0.002358, i = -6.11816e-5
j = 8.919726e-7, k = -5.59050e-9
Abstract: This study investigated the removal efficiency of electrokinetic remediation of copper-contaminated soil at different combinations of enhancement reagents used as anolyte and catholyte. Sodium hydroxide (at 0.1, 0.5, and 1.0 M concentrations) and distilled water were used as anolyte, while lactic acid (at 0.01, 0.1, and 0.5 M concentrations), ammonium citrate (also at 0.01, 0.1, and 0.5 M concentrations) and distilled water were used as catholyte. A continuous voltage application (1.0 VDC/cm) was employed for 240 hours for each experiment. The copper content of the catholyte was determined at the end of the 240-hour period. Optimization was carried out with a Response Surface Methodology - Optimal Design, including F test, and multiple comparison method, to determine which pair of anolyte-catholyte was the most significant for the removal efficiency. "1.0 M NaOH" was found to be the most significant anolyte while it was established that lactic acid was the most significant type of catholyte to be used for the most successful electrokinetic experiments. Concentrations of lactic acid should be at the range of 0.1 M to 0.5 M to achieve maximum percent removal values.
Abstract: Boron minerals are very useful for various industrial
activities, such as glass industry and detergent industry, due to its
mechanical and chemical properties. During the production of boron
compounds, many of these are introduced into the environment in the
form of waste. Boron is also an important micro nutrient for the
plants to vegetate but if it exists in high concentrations, it could have
toxic effects. The maximum boron level in drinking water for human
health is given as 0.3 mg/L in World Health Organization (WHO)
standards. The toxic effects of boron should be noted especially for
dry regions, thus, in recent years, increasing attention has been paid
to remove the boron from waste waters. In this study, boron removal
is implemented by ion exchange process using Amberlite IRA-743
resin. Amberlite IRA-743 resin is a boron specific resin and it
belongs to the polymerizate sorbent group within the aminopolyol
functional group. Batch studies were performed to investigate the
effects of various experimental parameters, such as adsorbent dose,
initial concentration and pH, on the removal of boron. It is found
that, when the adsorbent dose increases removal of boron from the
liquid phase increases. However, an increase in the initial
concentration decreases the removal of boron. The effective pH
values for removal of boron are determined between 8.5 and 9.
Equilibrium isotherms were also analyzed by Langmuir and
Freundlich isotherm models. The Langmuir isotherm is obeyed better
than the Freundlich isotherm.