Authors:S. Pourmortazavi, S. Hajimirsadeghi, and S. Hosseini
Thermogravimetry (TG) and differential thermal analysis
(DTA) in the non-isothermal mode have been used to examine the thermal behaviour
of the micron sized aluminum (Al) powder/potassium chlorate pyrotechnic systems
in air, in relation to the behaviour of the individual constituents. The effects
of different parameters of Al powder, such as particle size and its content
in the mixtures, on their thermal property were investigated. The results
showed that, the reactivity of Al powder in air increases as the particle
size decreases. Also, it was found that neat Al with 5 m particle sizes
(Al5) has a fusion temperature of about 647C,
that for 18 m powder (Al18) is 660C. Pure
potassium chlorate has a fusion temperature around 356C and decomposes
at 472C. DTA curves for Al5/KClO3
(30:70) mixture showed a maximum peak temperature for the ignition of mixture
at 485C. Also, by increasing the particle size of Al powder, the ignition
temperature of the mixture increased. On the other hand, the oxidation temperature
increased by enhancing the Al content of the mixtures. In this particular
study, we observed that the width of reaction peak for the mixtures corresponds
to their Al contents of samples.
Authors:S. Masoud Hosseini, A. Moghadassi, and Dale Henneke
This article presents a model, based on dimensionless groups, to predict the viscosity of nanoparticle suspensions, nanofluids.
This empirical model expresses the viscosity of a nanofluid as a function of the following: viscosity of the base liquid,
particle volume fraction, particle size, properties of the surfactant layer, and temperature. According to this model, viscosity
changes nonlinearly with nanoparticle loading. Compared to other models, the new model is in good agreement with experimentally
determined viscosity data for alumina–water nanofluids.
Authors:S. Hosseini, A. Moghadassi, D. Henneke, and Ali Elkamel
Changes in the thermal conductivities of paraffin and mono ethylene glycol (MEG) as a function of β-SiC nanoparticle concentration
and size was studied. An enhancement in the effective thermal conductivity was found for both fluids (i.e., both paraffin
and MEG) upon the addition of nanoparticles. Although an enhancement in thermal conductivity was found, the degree of enhancement
depended on the nanoparticle concentration in a complex way. An increase in particle-to-particle interactions is thought to
be the cause of the enhancement. However, the enhancement became muted at higher particle concentrations compared to lower
ones. This phenomenon can be related to nanoparticles interactions. An improvement in the thermal conductivities for both
fluids was also found as the nanoparticle size shrank. It is believed that the larger Brownian motion for smaller particles
causes more particle-to-particle interactions, which, in turn, improves the thermal conductivity. The role that the base-fluid
plays in the enhancement is complex. Lower fluid viscosities are believed to contribute to greater enhancement, but a second
effect, the interaction of the fluid with the nanoparticle surface, can be even more important. Nanoparticle-liquid suspensions
generate a shell of organized liquid molecules on the particle surface. These organized molecules more efficiently transmit
energy, via phonons, to the bulk of the fluid. The efficient energy transmission results in enhanced thermal conductivity.
The experimentally measured thermal conductivities of the suspensions were compared to a variety of models. None of the models
proved to adequately predict the thermal conductivities of the nanoparticle suspensions.
Authors:S. Hosseini, A. Mohamad, A. Kadhum, and W. Wan Daud
A study concerned to thermogravimetric analysis is performed in cesium dihydrogen phosphate (CsH2PO4) that was synthesized, using cetyltrimethylammonium-bromide (CTAB), polyoxyethylene-polyoxypropylene (F-68) and mixture of
(F-68:CTAB) with two mole ratio 0.06 and 0.12 as surfactant. The dehydration behavior of particles was studied using thermal
gravimetric analysis and differential scanning calorimetric. Subsequently, the experimental results indicated that the first
dehydration temperature in the range of 237–239 °C upon heating, the second peaks occur at temperature range 290–295 °C and
overlapping in the thermogravimetric events is observed. The mass loss values are obtained in the range of 6.62–6.97 wt% that
is less than reported theoretical value 7.8 wt%. These values show well compatibility of reaction CsH2PO4 to Cs2H2P2O7 with 3.92 wt% whereas mass loss value of CsH2PO4 to CsPO3 is less than theoretical value 7.8 wt%. The activation energy of two steps dehydration are calculated using Kissinger equation
for the samples synthesized via CTAB and (F-68) with minimum value mass loss 6.62% and maximum value mass loss 6.97%, respectively.
The calculation results reveal that the reaction rate in the first step (CsH2PO4 → Cs2H2P2O7) is faster than the second step (CsH2PO4 → CsPO3). The weight loss values of the samples demonstrate that existence of CTAB can be considered as effective factor which prevents
more weight loss during the dehydration process.
The current method to detect antibody titre against infectious bursal disease virus (IBDV) in chickens is based on enzyme-linked immunosorbent assay (ELISA) using whole virus as coating antigen. Coating the ELISA plates requires a purified or at least semi-purified preparation of virus as antigen, which needs special skills and techniques. In this study, instead of using whole virus, recombinant protein of hexahistidine tag (His 6 tag) and VPX protein of IBDV expressed in
was used as an alternative antigen to coat the ELISA plates. There was a good correlation coefficient (R
= 0.972) between the results of the ELISA using plates coated with monoclonal antibody against His 6 tag and those of the commercial IBDV ELISA kit. Hence, His 6 tag and VPX recombinant protein expressed in
has the potential for the development of ELISA for the measurement of IBDV-specific antibody.
Authors:A. Moghadassi, S. Masoud Hosseini, D. Henneke, and A. Elkamel
Thermal conductivity is an important parameter in the field of nanofluid heat transfer. This article presents a novel model
for the prediction of the effective thermal conductivity of nanofluids based on dimensionless groups. The model expresses
the thermal conductivity of a nanofluid as a function of the thermal conductivity of the solid and liquid, their volume fractions,
particle size and interfacial shell properties. According to this model, thermal conductivity changes nonlinearly with nanoparticle
loading. The results are in good agreement with the experimental data of alumina-water and alumina-ethylene glycol based nanofluids.
Authors:Mahdi Sadeghi, Omid Kiavar, S. Hosseini, Rozhin Fatehi, and Claudio Tenreiro
The Nitinol stent was bombarded in a cyclotron at a flux rate of 4 μA/cm2 to produce 48V via 48Ti (p, n) 48V reaction. In this study dose distribution of 48V radioactive stent was investigated for renal arteries. Version X-2.6 of the MCNP Monte Carlo radiation transport system
code was employed to calculate dose distribution around the stent. As 48V is a mixed gamma and beta particle emitter, two separate runs of MCNP for both beta and gamma particles were performed and
the total deposited dose was acquired by adding the two mentioned values. In order to verify the simulation, the calculated
results have been compared with previous published data for the source. Calculated results show high dose gradient near the
stent and the maximum amount of dose deposits at the vessel wall. According to (AAPM) TG-60/149 protocol, the dosimetric parameters,
including geometry function, G(ρ,z), radial dose function, gL(ρ), and anisotropy function, F(ρ,z), were also determined.
Authors:Mahmoud Hosseini, H. Sadeghnia, S. Salehabadi, and M. Soukhtanloo
In the present study the contribution of estradiol in sex-dependent differences of pentylenetetrazole (PTZ)-induced seizures was investigated in rats. The rats were divided into four groups: 1) sham, 2) ovariectomized (OVX), 3) ovariectomized-estradiol (OVX-Est) and 4) male. The OVX-Est group received estradiol valerate (2 mg/kg; i.m/4 weeks) while, male, sham and OVX groups received vehicle. The animals were injected by PTZ (90 mg/kg). The latencies to minimal clonic seizures (MCS) and generalized tonic-clonic seizures (GTCS), were recorded. Serum 17β-estradiol and testosterone levels were also determined using an Elisa kit. GTCS latency in OVX rats was higher than in sham-operated animals (P < 0.05). MCS and GTCS latency in the male group was significantly higher than in the sham, OVX and OVX-Est groups (P < 0.001 and P < 0.01). There was no significant difference in MCS or GTCS latencies among OVX-Est, sham and OVX groups. Serum 17β-estradiol level in the OVX group was significantly lower than in the sham (P < 0.01) and in the OVX-Est group it was higher than in the sham, OVX and male groups (P < 0.01 and P < 0.001). Serum testosterone level in the male group was significantly higher than in all the other three groups (P < 0.001). It seems that testosterone probably has a more efficient role than estradiol in the gender dependent difference in seizure caused by PTZ in rats.