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Search Results: 1 - 10 of 1242 matches for " Mahdi Hadavi "
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A New Method of Voiced/Unvoiced Classification Based on Clustering  [PDF]
Mojtaba Radmard, Mahdi Hadavi, Mohammad Mahdi Nayebi
Journal of Signal and Information Processing (JSIP) , 2011, DOI: 10.4236/jsip.2011.24048
Abstract: In this paper, a new method for making v/uv decision is developed which uses a multi-feature v/uv classification algorithm based on the analysis of cepstral peak, zero crossing rate, and autocorrelation function (ACF) peak of short-time segments of the speech signal by using some clustering methods. This v/uv classifier achieved excellent results for identification of voiced and unvoiced segments of speech.
Nannostratigraphy and Palaeoecology of the Uppermost Mozduran Formation in the Jozak Section in West Kopet-Dagh (NE Iran)  [PDF]
Mohammad Anvar Moheghy, Fatemeh Hadavi
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.51003
Abstract:

This paper discusses the biostratigraphy and palaeoecology of calcareous nannofossils of the uppermost Mozduran Formation in the Jozak section in west Kopet-Dagh basin. The Mozduran Formation consists of white to grey Limestone. In the studied sections, samples are taken and prepared with smear slides. In the Jozak section, 17 species have been determined. Based on nannoplanktons and as a result of biostratigraphy studies, the nannofossil standard zones (CC4) are identified. According to this zone, the age of the studied thickness is Early Hauterivian in this section in west Kopet-Dagh basin. The presence of warm water indicators (Nannoconus, Watznaueria, Lithraphidites) suggests warm surface water conditions in the studied thickness. In the Jozak section based on Nannoconus spp.,

The Size Effect of TiO2 Anatase Nanoparticles on Photon Correlation Spectroscopy  [PDF]
Mohammad Saeed Hadavi, Soheil Sharifi, Somaye Jafari
Soft Nanoscience Letters (SNL) , 2012, DOI: 10.4236/snl.2012.24014
Abstract: In this work, the anataze phase of TiO2 nanoparticles was prepared by sol gel method. We changed time and temperature of calcinations to change size and property of nanoparticles. The Transmission Electron Microscopy and Scanning Electron Microscopy were used for characterization of the TiO2 nanoparticles. The nanoparticle size was increased with time and temperature. We found that the average size of samples was changed from 30 to 46 nm with changing temperature from 450℃ to 650℃ and at fixed temperature (450℃) with changing of calcination times from 1 to 3 hours, the size was changed from 30 to 58 nm. For study the dynamic of nanoparticles, the TiO2 nanoparticles were added to water with 2.4 weights present of particles to the water. The different size of TiO2 nanoparticles was studied with photon correlation spectroscopy. The relaxation time was increased with increasing of nanoparticle size and so diffusion coefficient was decreased.
Investigation of the Boundary between Abderaz and Kalat Formations Based on Calcareous Nannofossils in West Kopet-Dagh (NE IRAN)  [PDF]
Mohammad Anvar Moheghy, Fatemeh Hadavi, Behname Rahimi
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.33021
Abstract:

The biostratigraphy of calcareous nannofossils of the Cretaceous is investigated in the boundary between Abderaz and Kalat Formations through the record of species richness, diversity and distribution patterns in the west Kopet-Dagh region. The Kalat Formation comprising of coarse-grained detritus limestone with subordinate sandstone intercalations and the Abderaz Formation mainly consists of limestone, Shale and Limy marl. Nannofossils of this boundary in each of studied sections are listed and figured. 21 species in Ghalehzoo section, 29 species in Sheikh section and 19 species in Jozak section have been determined. Boistratigraphy based on calcareous nannofossil allow the identification of nannofossil standard zones CC21 and CC26 in all of sections, According to these zones in all of sections, the age of the studied thickness is Early Late Campanian-Late Late Maastrichtian in these sections.

Design and preparation of binary-binary SnO2-ZnO:F/MgF2/SiO2 transparent conducting oxide coatings
Z Shahedi,S Hadavi
Iranian Journal of Physics Research , 2012,
Abstract: In this study, we prepared the binary-binary TCO compounds of SnO2-ZnO by the spray pyrolysis technique. We also investigated the role of MgF2/SiO2 antireflection coatings in reducing optical reflectance in the visible region of TCO. Before preparation , we simulated the optical transmition of the films for optimizing the layer thicknesses. The results of this study showed increasing of optical transmittance in the visible region of TCO by adding antireflection coating layers.
The efficacy of ketamine gargles on postoperative sore throat
Maryam Hadavi,Mohsen Rezaeian
Zahedan Journal of Research in Medical Sciences , 2011,
Abstract: Background: Sore throat is one of the major post-operative complications. Despite efforts to reduce sore throat, this complication is still one of the main problems after surgery. The aim of this study was to analyze the effectiveness of ketamine gargle on sore throat after tracheal intubation.Materials and method: This double blind clinical trial was performed on 120, ASA-I and II, patients undergoing elective surgery for herniorrhaphy under general anesthesia. Patients in group 1 were gargled 40 mg ketamine in 30mg saline and in group 2, only 30ml saline. For third group we did not do any intervention. Postoperative sore throat was graded at 0, 2, 4 and 24 h after operation on Verbal Analogue Scale (0-4).Results: Postoperative sore throat occurred less frequently in group 1, when compared with groups 2 and 3, but the difference was not significant. Frequently sore throat was reported at two hours after surgery. In this study, there was no severe (score 3) or very severe (score 4) sore throat. No systemic or local side effects were observed. Conclusion: In this study, ketamine gargle reduced the incidence and severity of post-operative sore throat. Therefore, gargling of ketamine solution is recommended for cases that need to tracheal intubation, especially when the probability of difficult intubation and post-operative sore throat is high
Effect of Added Extra Calcium Carbonate into the Diets, One Hour Before Starting Dark Period on Performance and Egg Quality of Laying Hens
H. Kermanshahi,A. Hadavi
International Journal of Poultry Science , 2006,
Abstract: In order to study the effect of four levels of extra calcium carbonate as limestone (0, 1, 2 and 3 g/hen/day, laying hen size, 3-4 mm) in a finished standard diets of laying hens, one hour before starting dark period, 160 Hy-line W36 laying hens, 85 weeks of age (after force molting) were selected and tested in a completely randomized block design with four treatments and four replicates. In a period of 8 weeks, feed intake (FI), egg weigh (EW), the number of cracked eggs (CE), the number of broken eggs (BE) and hen day egg production (HDEP) recorded daily. Eggshell quality including eggshell weight (ESW) and eggshell thickness (EST) were recorded every two weeks. CE, BE, ESW and EST were significantly improved by adding extra levels of calcium carbonate into the finished diets (P< 0.05). The highest incidence of CE and BE were seen in treatment one (control diet with no added extra calcium carbonate) and the lowest incidence of these traits were seen in treatment four (3 g/hen/day extra calcium carbonate). The best and the worst quality of ESW and EST were also seen in treatment four and one, respectively. Under the conditions of this study, it was concluded that use of 3g/hen/day extra calcium carbonate before starting the dark period in laying hens improves egg quality traits and therefore more benefits to egg producers and more healthy eggs for consumers.
Study on the Systemic Effect of Root-knot Nematode ( Meloidogyne javanica ) on Phenylalanine Ammonia Lyase Enzyme Activity in Tomato Root in the Interaction Between Root-Knot Nematode and Tomato Fusarium Wilt ( Fusarium oxysporum f.sp. lycopersici )
N. Sahebani,N. Hadavi
Journal of Science and Technology of Agriculture and Natural Resources , 2008,
Abstract: This research was conducted to study the effect of nematode (Meloidogyne javanica) on severity of tomato Fusarium wilt (Fusarium oxysporum f.sp. lycopersici race 1) and changes in Phenylalanine ammonia lyase (PAL) activity in split-root assays to show the possibility of systemic induced susceptibility caused by nematode to the fungus by local nematode infection. The results showed that the activity of nematode in one part of root confered susceptibility to Fusarium wilt in other part of the plant root and subsequently disease symptoms increased significantly in comparison to the control (without nematode inoculation). PAL specific activity showed a significant decrease in one half of split-root inoculated with fungus when the other half was inoculated with nematode as compared with the control (without nematode inoculation). Based on the results obtained in this study, nematode infection in one part of tomato plant root resulted in suppression of tomato defenses in all parts of the root, reduced tolerance or resistance to the fungus (as secondary pathogen) and intensified the fungal disease.
Towards Economic Single-Phase Motor  [PDF]
Mahdi Alshamasin
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.59058
Abstract:

Studying of operation balance in single-phase induction motors is an issue of interest due to the need for reducing the power consumption and increasing the motors’ life. The paper focuses on improving the motor performance by balancing the stator phase operation for the most common-used connection diagrams of single-phase capacitor-run induction motors (SPCRIMs) and three-phase induction motors (TPIMs) operating from single-phase supply (SPS). Therefore, a mathematical model is used to balance the motor operation by varying the frequency supply voltage. Characteristics of balancing parameters are investigated, various methods of motor balancing are presented and comparisons were done among these balancing methods.

Improvment of Free Convection Heat Transfer Rateof Rectangular Heatsink on Vertical Base Plates  [PDF]
HamidReza Goshayeshi, Mahdi Fahiminia, Mohammad Mahdi Naserian
Energy and Power Engineering (EPE) , 2011, DOI: 10.4236/epe.2011.34064
Abstract: In this paper, the laminar heat transfer of natural convection on vertical surfaces is investigated. Most of the studies on natural convection have been considered constantly whereas velocity and temperature domain, do not change with time, transient one are used a lot. Governing equations are solved using a finite volume approach. The convective terms are discretized using the power-law scheme, whereas for diffusive terms the central difference is employed. Coupling between the velocity and pressure is made with SIMPLE algorithm. The resultant system of discretized linear algebraic equations is solved with an alternating direction implicit scheme. Then a configuration of rectangular fins is put in different ways on the surface and heat transfer of natural convection on these surfaces without sliding is studied and finally optimization is investigated.
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