Abstract: Ionic liquids are well known as green solvents, reaction media and catalysis. Here, three different sulfonic acid functional ionic liquids prepared in the laboratory are used as catalysts in alkylation of p-cresol with tert-butyl alcohol. The kinetics on each of the catalysts was compared and a kinetic model was developed based on the product distribution over these catalysts. The kinetic parameters were estimated using Marquadt's algorithm to minimize the error function. The Arrhenius plots show a curvature which is best interpreted by the extended Arrhenius equation.
Abstract: This paper describes the design and development of pico-hydro generation system using consuming water distributed to houses. Water flow in the domestic pipes has kinetic energy that potential to generate electricity for energy storage purposes in addition to the routine activities such as laundry, cook and bathe. The inherent water pressure and flow inside the pipe from utility-s main tank that used for those usual activities is also used to rotate small scale hydro turbine to drive a generator for electrical power generation. Hence, this project is conducted to develop a small scale hydro generation system using consuming water distributed to houses as an alternative electrical energy source for residential use.
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: The expression of LFA-1 diverges from the
physiological condition, thus active targeting carrier can provide the
benefits from difference into LFA-1 expression in various conditions.
Here, the selectivity of cIBR-conjugated nanoparticles (cIBR-NPs),
in terms of uptake, was investigated using PBMCs, Mixed PBMCMolt-
3 cells and Molt-3 cells. The expressions of LFA-1 on Molt-3
cells, from flow cytometry and Western blot, possessed the highest
level whereas PBMCs showed the lowest level. The kinetic uptake
profiles of cIBR-NPs were obtained by flow cytometry, which the
degree of cellular uptake presented a similar trend with the level of
LFA-1 indicating the influence of LFA-1 expression on the cellular
uptake of cIBR-NPs. The conformation of LFA-1 had a slight effect
on the cellular uptake of cIBR-NPs. Overall we demonstrated that
cIBR-NPs enhanced cellular uptake and improved the selectivity of
drug carriers to LFA-1 on the leukemia cells, which related with the
order of LFA-1 expression.
Abstract: Chicken feathers were used as biosorbent for Pb
removal from aqueous solution. In this paper, the kinetics and
equilibrium studies at several pH, temperature, and metal
concentration values are reported. For tested conditions, the Pb
sorption capacity of this poultry waste ranged from 0.8 to 8.3 mg/g.
Optimal conditions for Pb removal by chicken feathers have been
identified. Pseudo-first order and pseudo-second order equations
were used to analyze the experimental data. In addition, the sorption
isotherms were fitted to classical Langmuir and Freundlich models.
Finally, thermodynamic parameters for the sorption process have
been determined. In summary, the results showed that chicken
feathers are an alternative and promising sorbent for the treatment of
effluents polluted by Pb ions.
Abstract: The conventional production of biodiesel from crude
palm oil which contains large amounts of free fatty acids in the
presence of a homogeneous base catalyst confronts the problems of
soap formation and very low yield of biodiesel. To overcome these
problems, free fatty acids must be esterified to their esters in the
presence of an acid catalyst prior to alkaline-catalyzed
transesterification. Sulfated metal oxides are a promising group of
catalysts due to their very high acidity. In this research, aluminadoped
sulfated tin oxide (SO4
2-/Al2O3-SnO2) catalysts were prepared
and used for esterification of free fatty acids in crude palm oil in a
batch reactor. The SO4
2-/Al2O3-SnO2 catalysts were prepared from
different Al precursors. The results showed that different Al
precursors gave different activities of the SO4
2-/Al2O3-SnO2 catalysts.
The esterification of free fatty acids in crude palm oil with methanol
in the presence of SO4
2-/Al2O3-SnO2 catalysts followed first-order
kinetics.
Abstract: Chemical reaction and diffusion are important phenomena in quantitative neurobiology and biophysics. The knowledge of the dynamics of calcium Ca2+ is very important in cellular physiology because Ca2+ binds to many proteins and regulates their activity and interactions Calcium waves propagate inside cells due to a regenerative mechanism known as calcium-induced calcium release. Buffer-mediated calcium diffusion in the cytosol plays a crucial role in the process. A mathematical model has been developed for calcium waves by assuming the buffers are in equilibrium with calcium i.e., the rapid buffering approximation for a one dimensional unsteady state case. This model incorporates important physical and physiological parameters like dissociation rate, diffusion rate, total buffer concentration and influx. The finite difference method has been employed to predict [Ca2+] and buffer concentration time course regardless of the calcium influx. The comparative studies of the effect of the rapid buffered diffusion and kinetic parameters of the model on the concentration time course have been performed.
Abstract: Malate dehydrogenase-glutamate oxaloacetate
aminotransferase (MDh-GOAT) enzyme complex (the EC) was
isolated and purified from wheat and rise, their some main physicchemical
properties were studied. Michael-s constants of the EC
MDh-GOAT to malate, glutamate and NAD were investigated. This
kinetic results show a high relationship to glutamate. Taking into
account important role of the the EC in catabolism of glutamate – the
central amino acid of a nitric exchange, there is a sharp necessity of
deeper studying of this enzyme complex. Therefore the basic purpose
of the work is studying the basic physical and chemical properties of
this enzyme complex discovered by us, which would be very
important for understanding the mechanisms of reaction catalyzed by
the EC.
Abstract: The purpose of this study was to understand the main
sources of copper (Cu) accumulation in target organs of tilapia
(Oreochromis mossambicus) and to investigate how the organism
mediate the process of Cu accumulation under prolonged conditions.
By measuring both dietary and waterborne Cu accumulation and total
concentrations in tilapia with biokinetic modeling approach, we were
able to clarify the biokinetic coping mechanisms for the long term Cu
accumulation. This study showed that water and food are both the
major source of Cu for the muscle and liver of tilapia. This implied
that control the Cu concentration in these two routes will be correlated
to the Cu bioavailability for tilapia. We found that exposure duration
and level of waterborne Cu drove the Cu accumulation in tilapia. The
ability for Cu biouptake and depuration in organs of tilapia were
actively mediated under prolonged exposure conditions. Generally,
the uptake rate, depuration rate and net bioaccumulation ability in all
selected organs decreased with the increasing level of waterborne Cu
and extension of exposure duration.Muscle tissues accounted for over
50%of the total accumulated Cu and played a key role in buffering the
Cu burden in the initial period of exposure, alternatively, the liver
acted a more important role in the storage of Cu with the extension of
exposures. We concluded that assumption of the constant biokinetic
rates could lead to incorrect predictions with overestimating the
long-term Cu accumulation in ecotoxicological risk assessments.
Abstract: Characterization and evaluation of the activity of Vespa basalis DPP-IV, which expressed in Spodoptera frugiperda 21 cells. The expression of rDPP-IV was confirmed by SDS–PAGE, Western blot analyses, LC-MS/MS and measurement of its peptidase specificity. One-step purification by Ni-NTA affinity chromatography and the total amount of rDPP-IV recovered was approximately 6.4mg per liter from infected culture medium; an equivalent amount would be produced by 1x109 infected Sf21 insect cells. Through the affinity purification led to highly stable rDPP-IV enzyme was recovered and with significant peptidase activity. The rDPP-IV exhibited classical Michaelis–Menten kinetics, with kcat/Km in the range of 10-500 mM-1×S-1 for the five synthetic substrates and optimum substrate is Ala-Pro-pNA. As expected in inhibition assay, the enzymatic activity of rDPP-IV was significantly reduced by 80 or 60% in the presence of sitagliptin (a DPP-IV inhibitor) or PMSF (a serine protease inhibitor), but was not apparently affected by iodoacetamide (a cysteine protease inhibitor).
Abstract: Residual dye contents in textile dyeing wastewater have complex aromatic structures that are resistant to degrade in biological wastewater treatment. The objectives of this study were to determine the effectiveness of nanoscale zerovalent iron (NZVI) to decolorize Reactive Black 5 (RB5) and Reactive Red 198 (RR198) in synthesized wastewater and to investigate the effects of the iron particle size, iron dosage and solution pHs on the destruction of RB5 and RR198. Synthesized NZVI was confirmed by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The removal kinetic rates (kobs) of RB5 (0.0109 min-1) and RR198 (0.0111 min-1) by 0.5% NZVI were many times higher than those of microscale zerovalent iron (ZVI) (0.0007 min-1 and 0.0008 min-1, respectively). The iron dosage increment exponentially increased the removal efficiencies of both RB5 and RR198. Additionally, lowering pH from 9 to 5 increased the decolorization kinetic rates of both RB5 and RR198 by NZVI. The destruction of azo bond (N=N) in the chromophore of both reactive dyes led to decolorization of dye solutions.
Abstract: Anaerobic Digestion has become a promising
technology for biological transformation of organic fraction of the
municipal solid wastes (MSW). In order to represent the kinetic
behavior of such biological process and thereby to design a reactor
system, development of a mathematical model is essential.
Addressing this issue, a simplistic mathematical model has been
developed for anaerobic digestion of MSW in a continuous flow
reactor unit under homogeneous steady state condition. Upon
simulated hydrolysis, the kinetics of biomass growth and substrate
utilization rate are assumed to follow first order reaction kinetics.
Simulation of this model has been conducted by studying sensitivity
of various process variables. The model was simulated using typical
kinetic data of anaerobic digestion MSW and typical MSW
characteristics of Kolkata. The hydraulic retention time (HRT) and
solid retention time (SRT) time were mainly estimated by varying
different model parameters like efficiency of reactor, influent
substrate concentration and biomass concentration. Consequently,
design table and charts have also been prepared for ready use in the
actual plant operation.
Abstract: Based on a global kinetics of direct dimethyl ether (DME) synthesis process from syngas, a steady-state one-dimensional mathematical model for the bubble column slurry reactor (BCSR) has been established. It was built on the assumption of plug flow of gas phase, sedimentation-dispersion model of catalyst grains and isothermal chamber regardless of reaction heats and rates for the design of an industrial scale bubble column slurry reactor. The simulation results indicate that higher pressure and lower temperature were favorable to the increase of CO conversion, DME selectivity, products yield and the height of slurry bed, which has a coincidence with the characteristic of DME synthesis reaction system, and that the height of slurry bed is lessen with the increasing of operation temperature in the range of 220-260℃. CO conversion, the optimal operation conditions in BCSR were proposed.
Abstract: Polarization modulation infrared reflection absorption
spectroscopy (PM-IRRAS) in combination with electrochemistry,
was employed to study the influence of surface charge (potential) on
the kinetics of bovine serum albumin (BSA) adsorption on a
biomedical-grade 316LVM stainless steel surface is discussed. The
BSA adsorption kinetics was found to greatly depend on the surface
potential. With an increase in surface potential towards more
negative values, both the BSA initial adsorption rate and the
equilibrium (saturated) surface concentration also increased. Both
effects were explained on the basis of replacement of well-ordered
water molecules at the 316LVM / solution interface, i.e. by the
increase in entropy of the system.
Abstract: The turbulent mixing of coolant streams of different
temperature and density can cause severe temperature fluctuations in
piping systems in nuclear reactors. In certain periodic contraction
cycles these conditions lead to thermal fatigue. The resulting aging
effect prompts investigation in how the mixing of flows over a sharp
temperature/density interface evolves. To study the fundamental
turbulent mixing phenomena in the presence of density gradients,
isokinetic (shear-free) mixing experiments are performed in a square
channel with Reynolds numbers ranging from 2-500 to 60-000.
Sucrose is used to create the density difference. A Wire Mesh Sensor
(WMS) is used to determine the concentration map of the flow in the
cross section. The mean interface width as a function of velocity,
density difference and distance from the mixing point are analyzed
based on traditional methods chosen for the purposes of
atmospheric/oceanic stratification analyses. A definition of the
mixing layer thickness more appropriate to thermal fatigue and based
on mixedness is devised. This definition shows that the thermal
fatigue risk assessed using simple mixing layer growth can be
misleading and why an approach that separates the effects of large
scale (turbulent) and small scale (molecular) mixing is necessary.
Abstract: The Kinetics formation of labile Complex
Ag (I) tetra (p-carboxyphenyl) porphyrin, was investigated at 25oC
and I=0.1M (NaNO3). By spectrophotometric titration, the
composition ratio of the complex was established to be 2:1
(Ag : H2TCPP). The equilibrium constant, K, was found to be
log 10-6.53. Binding of the first Ag (I) was found to be rate
determining step with rate constant, k1= 4.67×102 . A plausible
mechanism is discussed. We discus theoretically why Ag(I)2TCPP is
unstable.
Abstract: The aim of this paper is to present the role of
myotonometry in assessment muscle viscoelasticity by measurement
of force index (IF) and stiffness (S) at thigh muscle groups. The
results are used for improve the muscle training. The method is based
on mechanic impulse on the muscle group, that involve a muscle
response like acceleration, speed and amplitude curves. From these
we have information about elasticity, stiffness beginning from
mechanic oscillations of muscle tissue. Using this method offer the
possibility for monitoring the muscle capacity for produce mechanic
energy, that allows a efficiency of movement with a minimal tissue
deformation.
Abstract: The hydrolysis kinetics of polycrystalline lithium hydride (LiH) in argon at various low humidities was measured by gravimetry and Raman spectroscopy with ambient water concentration ranging from 200 to 1200 ppm. The results showed that LiH hydrolysis curve revealed a paralinear shape, which was attributed to two different reaction stages that forming different products as explained by the 'Layer Diffusion Control' model. Based on the model, a novel two-stage rate equation for LiH hydrolysis reactions was developed and used to fit the experimental data for determination of Li2O steady thickness Hs and the ultimate hydrolysis rate vs. The fitted data presented a rise of Hs as ambient water concentration cw increased. However, in spite of the negative effect imposed by Hs increasing, the upward trend of vs remained, which implied that water concentration, rather than Li2O thickness, played a predominant role in LiH hydrolysis kinetics. In addition, the proportional relationship between vsHs and cw predicted by rate equation and confirmed by gravimetric data validated the model in such conditions.
Abstract: In the present research, steam cracking of two types of
feedstocks i.e., naphtha and ethane is simulated for Pyrocrack1-1 and
2/2 coil configurations considering two key parameters of coil outlet
temperature (COT) and coil capacity using a radical based kinetic
model. The computer model is confirmed using the industrial data
obtained from Amirkabir Petrochemical Complex. The results are in
good agreement with performance data for naphtha cracking in a
wide range of severity (0.4-0.7), and for ethane cracking on various
conversions (50-70). It was found that Pyrocrack2-2 coil type is an
appropriate choice for steam cracking of ethane at reasonable
ethylene yield while resulting in much lower tube wall temperature
while Pyrocrack1-1 coil type is a proper selection for liquid
feedstocks i.e. naphtha. It can be used for cracking of liquid
feedstocks at optimal ethylene yield whereas not exceeding the
allowable maximum tube temperature.
Abstract: Prolonged immobilization leads to significant
weakness and atrophy of the skeletal muscle and can also impair the
recovery of muscle strength following injury. Therefore, it is
important to minimize the period under immobilization and accelerate
the return to normal activity. This study examined the effects of heat
treatment and rest-inserted exercise on the muscle activity of the lower
limb during knee flexion/extension. Twelve healthy subjects were
assigned to 4 groups that included: (1) heat treatment + rest-inserted
exercise; (2) heat + continuous exercise; (3) no heat + rest-inserted
exercise; and (4) no heat + continuous exercise. Heat treatment was
applied for 15 mins prior to exercise. Continuous exercise groups
performed knee flexion/extension at 0.5 Hz for 300 cycles without rest
whereas rest-inserted exercise groups performed the same exercise but
with 2 mins rest inserted every 60 cycles of continuous exercise.
Changes in the rectus femoris and hamstring muscle activities were
assessed at 0, 1, and 2 weeks of treatment by measuring the
electromyography signals of isokinetic maximum voluntary
contraction. Significant increases in both the rectus femoris and
hamstring muscles were observed after 2 weeks of treatment only
when both heat treatment and rest-inserted exercise were performed.
These results suggest that combination of various treatment techniques,
such as heat treatment and rest-inserted exercise, may expedite the
recovery of muscle strength following immobilization.