Evaluation of strength properties of cement stabilized sand mixed with EPS beads and fly ash

Chenari, Reza Jamshidi,Fatahi, Behzad,Ghorbani, Ali,Alamoti, Mohsen Nasiri Techno-Press 2018 Geomechanics & engineering Vol.14 No.6

The importance of using materials cost effectively to enhance the strength and reduce the cost, and weight of earth fill materials in geotechnical engineering led researchers to seek for modifying the soil properties by adding proper additives. Lightweight fill materials made of soil, binder, water, and Expanded polystyrene (EPS) beads are increasingly being used in geotechnical practices. This paper primarily investigates the behavior of sandy soil, modified by EPS particles. Besides, the mechanical properties of blending sand, EPS and the binder material such as fly ash and cement were examined in different mixing ratios using a number of various laboratory studies including the Modified Standard Proctor (MSP) test, the Unconfined Compressive Strength (UCS) test, the California Bearing Ratio (CBR) test and the Direct Shear test (DST). According to the results, an increase of 0.1% of EPS results in a reduction of the density of the mixture for 10%, as well as making the mixture more ductile rather than brittle. Moreover, the compressive strength, CBR value and shear strength parameters of the mixture decreases by an increase of the EPS beads, a trend on the contrary to the increase of cement and fly ash content.

Study on the effects of processing parameters on the CVD alumina coating

Nasim Chenari,Mansour Soltanieh,Arash Yazdani 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.6

The CVD alumina coatings were deposited on carbide cutting tools using gas mixtures of H2, CO2 and AlCl3 at the temperatures between 960-1000 o C, one atmosphere pressure and for different gas flows of H2, CO2. The AlCl3 gas is produced in a generator by passing the HCl gas through the mechanically worked aluminium granules. In a simulated laboratory setup it was found that the reactivity of aluminium granules with HCl was increased drastically. Thickness measurements showed that by using worked granules, the alumina thickness for the same conditions increases from 0.75 to 3 µm. Moreover, it was found that with increasing the coating temperature and flow of gases, deposition rate was increased. Calculations showed that the process is far from the equilibrium condition. It was found that the reaction is kinetically mass transfer controlled in the boundary layer. The activation energy of the process was equal to 207.02 Kj/mol.

Frequency dependence of ultrahigh dielectric constant of novel synthesized SnO_2 nanoparticles thick films

H. Mahmoudi Chenari,Ali Hassanzadeh,M.M. Golzan,H. Sedghi,M. Talebian 한국물리학회 2011 Current Applied Physics Vol.11 No.3

In this work, the electric and dielectric properties of nanocrystalline SnO_2 thick films were studied using ac impedance spectroscopy under different conditions through capacitanceefrequency measurements in frequency range from 1 Hz to 1 MHz and bias voltage range from 0 V to 2 V. Results showed that dielectric constant (ε´), dielectric loss (ε″), loss tangent (tan δ), ac electrical conductivity (σ) and the electric modulus (M) are strongly frequency dependent. A decrease in frequency accompanied with an increase in ε´ and ε″ values. Whereas, ac electrical conductivity (σ), real (M^Ⅰ) and imaginary parts of electric modulus (M^Ⅱ) values are increased with frequency increasing. A comparative study showed that our prepared thick films have greater dielectric value than that of the reported data; hence can be used them as ultrahigh dielectric materials.

Frequency dependence of dielectric properties and electrical conductivity of Cu/nano-SnO_2 thick film/Cu arrangement

H. Mahmoudi Chenari,M.M. Golzan,H. Sedghi,A. Hassanzadeh,M. Talebian 한국물리학회 2011 Current Applied Physics Vol.11 No.4

The dielectric properties of Cu/nano-SnO_2 thick film/Cu arrangement were studied by means of complex impedance spectroscopy and frequency dependence of capacitance measured from the impedance data at a range of frequency intervals between 1 Hz and 1 MHz with a voltage between 0 and 2 V. The frequency dependence of the dielectric constant ε´, dielectric loss ε″, loss tangent (tan δ), electric modulus M´ and M″ and AC electrical conductivity (σ_ac) of the sandwich arrangement was subsequently investigated. Experimental results revealed that the aforementioned parameters have strong frequency dependence. The obtained values of ε´, ε″ showed increments with decreasing frequency. However,increasing frequency levels cause an increase in the AC electrical conductivity (σ), real and imaginary part of electric modulus. In addition to this, in order to gain an insight into the electric nature of Cu/nano-SnO_2 thick film/Cu arrangement device, the Cole―Cole diagrams of the electric modulus were investigated at different voltages.

Proposed Pathway Linking Respiratory Infections with Depression

Zeinab Karimi,Maryam Chenari,Farhad Rezaie,Shima Karimi,Najmeh Parhizgari,Talat Mokhtari-Azad 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.2

Depression is one of the most important causes of disability and loss of useful life of people around the world. Acute respiratory infection caused a large number of severe illnesses and deaths of the world and most of these due to viral infections, which is estimated more than 80% of respiratory infections. Detection of viruses by immune pathogen recognition receptors activates the intracellular signaling cascade and eventually cause produces interferons. Inflammatory process begins with secretion of interferons and the expression of interferon-stimulated genes. One of the most important of these genes is indoleamine-pyrrole 2,3-dioxygenase (IDO), which plays a major role in tryptophan catabolism. IDO is an intracellular monomeric enzyme that is also responsible for breaking down and consuming tryptophan in the Kynurenine pathway. Increased inflammation has been linked to decrease tryptophan concentrations and increase kynurenine levels. We tried to explain the role of inflammation by viral respiratory infections in causing depression.

Cyclic and Post-Cyclic Shear Behaviour of Interface between Geogrid and EPS Beads-Sand Backfill

Reza Alaie,Reza Jamshidi Chenari 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.9

Lightweight sand–EPS beads composite is a new artificial geo-material, which has been recently found applications in geotechnical engineering projects. A series of laboratory tests were carried out using a large-scale cyclic direct shear test apparatus to evaluate the monotonic, cyclic and post-cyclic behaviour of an interface between EPS-sand mixtures and a Polyfelt geogrid. EPS were added to sand at 0%, 0.5%, 1%, and 2% by weight. Tests were conducted under three different vertical stresses (30 kPa, 60 kPa and 90 kPa). The influences of cyclic shear semi-amplitude, number of cycles and normal stress on interface properties are investigated. The test results revealed that for a given strain level, interface shear stiffness decreases and damping ratio was shown to increase with increasing EPS content. Hardening behaviour was observed with the number of cycles under different normal stress levels and EPS contents. The EPS-sand-geogrid specimens did not develop clear peak shear stress at monotonic and post-cyclic direct shear tests. The EPS-sand-geogrid mixtures represent an overall contraction behaviour in monotonic, cyclic and post-cyclic stages. The apparent adhesion of interface was shown to increase and the friction angle of interface to decrease with EPS content.

Genistein Suppression of Matrix Metalloproteinase 2 (MMP-2) and Vascular Endothelial Growth Factor (VEGF) Expression in Mesenchymal Stem Cell Like Cells Isolated from High and Low Grade Gliomas

Yazdani, Yasaman,Rad, Mohammad Reza Sharifi,Taghipour, Mousa,Chenari, Nooshafarin,Ghaderi, Abbas,Razmkhah, Mahboobeh Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.12

Objective: Brain tumors cause great mortality and morbidity worldwide, and success rates with surgical treatment remain very low. Several recent studies have focused on introduction of novel effective medical therapeutic approaches. Genistein is a member of the isoflavonoid family which has proved to exert anticancer effects. Here we assessed the effects of genistein on the expression of MMP-2 and VEGF in low and high grade gliomas in vitro. Materials and Methods: High and low grade glioma tumor tissue samples were obtained from a total of 16 patients, washed with PBS, cut into small pieces, digested with collagenase type I and cultured in DMEM containing 10% FBS. When cells reached passage 3, they were exposed to genistein and MMP-2 and VEGF gene transcripts were determined by quantitative real time PCR (qRT-PCR). Results: Expression of MMP-2 demonstrated 580-fold reduction in expression in low grade glioma cells post treatment with genistein compared to untreated cells (P value= 0.05). In cells derived from high grade lesions, expression of MMP-2 was 2-fold lower than in controls (P value> 0.05). Genistein caused a 4.7-fold reduction in VEGF transcript in high grade glioma cells (P value> 0.05) but no effects were evident in low grade glioma cells. Conclusion. Based on the data of the present study, low grade glioma cells appear much more sensitive to genistein and this isoflavone might offer an appropriate therapeutic intervention in these patients. Further investigation of this possibility is clearly warranted.

Expression of Chemokines and Chemokine Receptors in Brain Tumor Tissue Derived Cells

Razmkhah, Mahboobeh,Arabpour, Fahimeh,Taghipour, Mousa,Mehrafshan, Ali,Chenari, Nooshafarin,Ghaderi, Abbas Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.17

Chemokine and chemokine receptor expression by tumor cells contributes to tumor growth and angiogenesis and thus these factors may be considered as tumor markers. Here we aimed to characterize cells directly extracted from glioma, meningioma, and secondary brain tumors as well as non-tumoral cells in vitro. Cells were isolated from brain tissues using 0.2% collagenase and characterized by flow cytometry. Expression of SDF-1, CXCR4, CXCR7, RANTES, CCR5, MCP-1 and IP-10 was defined using flow cytometry and qRT-PCR methods. Brain tissue isolated cells were observed as spindle-shaped cell populations. No significant differences were observed for expression of SDF-1, CXCR4, CXCR7, RANTES, CCR5, and IP-10 transcripts. However, the expression of CXCR4 was approximately 13-fold and 110-fold higher than its counterpart, CXCR7, in meningioma and glioma cells, respectively. CXCR7 was not detectable in secondary tumors but CXCR4 was expressed. In non tumoral cells, CXCR7 had 1.3-fold higher mRNA expression than CXCR4. Flow cytometry analyses of RANTES, MCP-1, IP-10, CCR5 and CXCR4 expression showed no significant difference between low and high grade gliomas. Differential expression of CXCR4 and CXCR7 in brain tumors derived cells compared to non-tumoral samples may have crucial impacts on therapeutic interventions targeting the SDF-1/CXCR4/CXCR7 axis.

Effect of CO2-laser irradiation on properties and performance of thin-film composite polyamide reverse osmosis membrane

Seyyed Abbas Mousavi,Foad Jahangiri,Fathollah Farhadi,Vahid Vatanpour,Behnam Sabzi,Zeinab Chenari 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3

CO2-laser irradiation was used to modify the surface properties of thin-film composite (TFC) polyamide reverse osmosis (RO) membranes. These membranes were first synthesized via interfacial polymerization of m-phenylenediamine (MPD) monomers and trimesoyl chloride (TMC) over porous polysulfone ultrafiltration support, followed by a CO2-irradiation. AFM, ATR-FTIR, SEM and contact angle measurements were used to characterize the surface properties of these membranes. The ATR-FTIR results indicated that CO2-laser irradiation did not induce any functional groups on the membrane surface. However, it was found that the laser irradiation enhanced the NaCl salt rejection and slightly reduced the permeate flux. Moreover, the maintenance of the flux in modified membranes was much higher than untreated ones. Specially, after 180 min of filtration, the reduction in initial flux for the unmodified membranes was 22%. However, the reduction in initial flux for the modified membranes was less than 5%. Bovine serum albumin (BSA) filtration revealed an improvement in the antifouling properties of the modified membranes. The changes in the membrane surface morphology showed that the roughness of membrane surface is reduced significantly.