Showing 4 results for Karimaei
N. Aleyasin , S. Karimaei , M. Talebi , M. Kashanian , Gh.r. Irajian ,
Volume 4, Issue 3 (Summer 2018)
Abstract
Aims: Diagnosis of Listeria monocytogenes infections is critical for epidemiological study and prevention of diseases. This study aimed at identifying L. monocytogenes isolates, using Loop-Mediated Isothermal Amplification Method (LAMP).
Materials & Methods: Listeria strains were obtained from clinical and seafood specimen. All listeria strains were identified by standard microbiological and biochemical tests. The LAMP assay was performed at 65°C with a detection limit of 2.5 ng/μl for 46 min. Specific primers for the hylA gene were used to identify L. monocytogenes. The specificity of the assay was assessed, using DNA from L. monocytogenes ATCC 7644 and L. ivanovii ATCC 19119 and non-Listeria strains. Sensitivity of the LAMP assay was compared with polymerase chain reaction (PCR) method. Amplification LAMP products were visualized via calcein and manganous ions as well as agarose gel electrophoresis.
Findings: A total of 191 samples were obtained, including clinical and food samples. Then, 21 (10.9%) isolates were recovered from specimens. The LAMP results showed high sensitivity (97.2%) and specificity (100 %). The LAMP assay was higher sensitive than of the PCR assay.
Conclusion: This data showed that this method could be used as a sensitive, rapid, and simple identification tool for diagnosis of L. monocytogenes isolates and it may be suitable for epidemiological study plans.
Volume 14, Issue 10 (1-2015)
Abstract
In this paper, 5 samples of one kind of swirl injector with tangential inlets, which has been designed and manufactured by using CNC, have been tested. Above injector has a spray cone in the shape of very thin layer because it is formed an air core in injector center. In fact, this is a one-fluid injector but its operation is two-phase. In order to detect acceptable injector among them, characterization tests have been done in the propulsion laboratory of Tarbiat Modarres University for all sample injectors. The methods of experimental characterization have been described in detail in current paper and also important parameters introduced. In these tests, injection uniformity, symmetry, mass flow rate versus pressure difference and some other parameter such as spray cone angle are investigated. Experimental results have been compared with design points. Finally, one injector has been selected as a suitable and nearer to theoretical design injector among them. The selected injector can be used for validation of numerical analysis results and also doing some complemental microscopic experiments. The results show good agreement between theoretical predictions and experimental results.
Volume 17, Issue 3 (5-2017)
Abstract
Prediction of spray droplet diameter distribution depends on the various parameters such as physical properties, fluid velocity, and discharge environment and injector geometry. The stage of forming droplets has a great variety in size and therefore will be predictable with a statistical approach. The maximum entropy principle is one of the most popular and best ways to predict the spray droplet size distribution along with the conservation equations. Due to some drawbacks in this model, the predicted results do not match well with the experimental data. It is suggested to improve the available energy source in the MEP model equation by numerical solution of flow inside the injector based on the CFD technique. This will enhance the calculation accuracy of the turbulent kinetic energy of the output spray. In fact, by using this sub-model in the maximum entropy model, the prediction accuracy of the spray characteristics is improved. Also, the requirement of the maximum entropy model to the experimental data as inputs has been reduced. By the present coupled model, the effect of spray upstream on the droplet size distribution can be considered with a good accuracy. The results show a close agreement with the available experimental data.
Volume 21, Issue 3 (5-2021)
Abstract
Sustainability helps the environment by reducing the consumption of non-renewable natural resources. Concrete uses a significant amount of non-renewable resources. Efforts aimed at producing environmentally friendly concrete can play a major role in securing sustainable construction. Candidate technologies for sustainable concrete materials include the incorporation of supplementary cementitious materials (SCMs) such as fly ash, silica fume and granulated blast furnace slag as a partial replacement for portland cement; the incorporation of recycled materials in concrete production. As a result, an experimental investigation was conducted to study the hardened properties of concrete constructed with 10% and 15% recycled tires (coarse and fine) as well as 6% silica fume. This experimental program consisted of ten mix designs. The hardened properties (compressive strength and tensile splitting strength) of concrete were compared with the provisions of the international design codes (U.S., Australia, Canada, Europe, and Japan). Results of this study show that using coarse recycled tires in the mix designs decreases compressive strengths between 35% and 45% and splitting tensile strength up to 20%. To overcome inferior hardened properties of recycled tire concrete mixes, silica fume (6%) has been added to the recycled tire concrete mixes. Results of the mixes including both recycled tire concrete and silica fume show better hardened properties compared with the mixes without silica fume, but still the hardened properties of the mixes with recycled tire and silica fume are less than the conventional concrete.
