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    3D Bioprinting of oxygenated cell-laden gelatin methacryloyl constructs

    , Article Advanced Healthcare Materials ; Volume 9, Issue 15 , 2020 Erdem, A ; Darabi, M. A ; Nasiri, R ; Sangabathuni, S ; Ertas, Y. N ; Alem, H ; Hosseini, V ; Shamloo, A ; Nasr, A. S ; Ahadian, S ; Dokmeci, M. R ; Khademhosseini, A ; Ashammakhi, N ; Sharif University of Technology
    Wiley-VCH Verlag  2020
    Cell survival during the early stages of transplantation and before new blood vessels formation is a major challenge in translational applications of 3D bioprinted tissues. Supplementing oxygen (O2) to transplanted cells via an O2 generating source such as calcium peroxide (CPO) is an attractive approach to ensure cell viability. Calcium peroxide also produces calcium hydroxide that reduces the viscosity of bioinks, which is a limiting factor for bioprinting. Therefore, adapting this solution into 3D bioprinting is of significant importance. In this study, a gelatin methacryloyl (GelMA) bioink that is optimized in terms of pH and viscosity is developed. The improved rheological properties... 

    Modeling of pressure line behavior of a common rail diesel engine due to injection and fuel variation

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 39, Issue 3 , 2017 , Pages 661-669 ; 16785878 (ISSN) Mohebbi, M ; Aziz, A. A ; Hamidi, A ; Hajialimohammadi, A ; Hosseini, V ; Sharif University of Technology
    Springer Verlag  2017
    Common rail diesel engines with electronic fuel injection can accurately meter the fuel injection quantity with more accurate fuel injection control capability. In this work a common rail fuel injection system of a single cylinder diesel engine has been proposed and the important parameters like injection pressure, energizing time and high pressure pipes diameter and length are designed such that to be compatible with the engine basic design in case of pressure waves and injected mass variations. A one-dimensional approach has been used to model the injector using AMESim code in which Adiabatic models have been used to model injector system. Injected mass quantity has been calculated for... 

    Modeling particle deposition in the respiratory system during successive respiratory cycles

    , Article Scientia Iranica ; Volume 27, Issue 1 B , February , 2020 , Pages 215-228 Nemati, H ; Saidi, M. S ; Hosseini, V ; Sharif University of Technology
    Sharif University of Technology  2020
    This study uses a 5-lobe symmetric model to investigate total, lobar and generational particle deposition fractions in the lungs during successive cycles. It was found that for the particle size between 0.05 and 2 μm and the tidal volumes greater than 1000 ml, the effect of successive cycles helped predict more deposition fraction per cycle up to about 16% than that of a single cycle. The mentioned range of tidal volumes corresponds to light or heavy physical activities. Therefore, it can be understood that people, when physically active, exposed to particulate matter within the mentioned size range are at higher health risk as compared to both the resting state and the same state... 

    Availability analysis on combustion of n-heptane and isooctane blends in a reactivity controlled compression ignition engine

    , Article Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering ; Volume 232, Issue 11 , 2018 , Pages 1501-1515 ; 09544070 (ISSN) Mohebbi, M ; Reyhanian, M ; Ghofrani, I ; Aziz, A. A ; Hosseini, V ; Sharif University of Technology
    SAGE Publications Ltd  2018
    Unfortunately, energy demands and destruction of the environment from uncontrolled manipulation of fossil fuels have increased. Climate change concerns have resulted in the rapid use of new, alternative combustion technologies. In this study, reactivity controlled compression ignition (RCCI) combustion, which can simply be exploited in internal combustion (IC) engines, is investigated. To introduce and identify extra insightful information, an exergy-based study was conducted to classify various irreversibility and loss sources. Multidimensional models were combined with the primary kinetics mechanism to investigate RCCI combustion, incorporating the second law of thermodynamics. The... 

    Assessment of emission reduction scenarios with a focus on the impact of vehicle fleets on tehran air quality: case study

    , Article Transportation Research Record ; Volume 2673, Issue 5 , 2019 , Pages 197-207 ; 03611981 (ISSN) Shahbazi, H ; Hosseini, V ; Torbatian, S ; Hamedi, M ; Sharif University of Technology
    SAGE Publications Ltd  2019
    In recent years, the city of Tehran has frequently experienced severe air pollution episodes, and the increase in the use of vehicles has exacerbated this critical situation. It is unclear to what extent each vehicle category contributes to the production of pollution during a pollution event. For this purpose, a combination of the weather research and forecasting (WRF) and the Comprehensive Air Quality Model with Extensions (CAMx) modeling systems was used to simulate the distributions of pollutant concentrations over Tehran in a pollution episode from December 3 to 23, 2017. First, the performance of the modeling system was evaluated with respect to the simulation outputs against... 

    Investigating the effect of the heat transfer correlation on the predictability of a multi-zone combustion model of a hydrogen-fuelled spark ignition engine

    , Article Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering ; Volume 230, Issue 1 , 2016 , Pages 70-81 ; 09544070 (ISSN) Tabatabaie, T ; Ehteram, M. A ; Hosseini, V ; Sharif University of Technology
    SAGE Publications Ltd 
    Research on the heat transfer in hydrogen-fuelled spark ignition engines indicates that the two most common heat transfer correlations, namely the Annand correlation and the Woschni correlation, cannot perfectly predict the heat flux during the engine cycle. This questions the accuracy of thermodynamic hydrogen engine models because the heat transfer is one of the important submodels in the development of a thermodynamic model. In addition, the Hohenberg correlation and the Shudo-Suzuki correlation have not been evaluated for hydrogen engines. In this study, a thermodynamic model of the closed cycle of a spark ignition engine is developed with a multi-zone combustion submodel to predict the... 

    Annual and seasonal spatial models for nitrogen oxides in Tehran, Iran

    , Article Scientific Reports ; Volume 6 , 2016 ; 20452322 (ISSN) Amini, H ; Taghavi Shahri, S. M ; Henderson, S. B ; Hosseini, V ; Hassankhany, H ; Naderi, M ; Ahadi, S ; Schindler, C ; Künzli, N ; Yunesian, M ; Sharif University of Technology
    Nature Publishing Group 
    Very few land use regression (LUR) models have been developed for megacities in low- and middle-income countries, but such models are needed to facilitate epidemiologic research on air pollution. We developed annual and seasonal LUR models for ambient oxides of nitrogen (NO, NO2, and NOX) in the Middle Eastern city of Tehran, Iran, using 2010 data from 23 fixed monitoring stations. A novel systematic algorithm was developed for spatial modeling. The R 2 values for the LUR models ranged from 0.69 to 0.78 for NO, 0.64 to 0.75 for NO 2, and 0.61 to 0.79 for NOx. The most predictive variables were: distance to the traffic access control zone; distance to primary schools; green space; official... 

    Network autoregressive model for the prediction of covid-19 considering the disease interaction in neighboring countries

    , Article Entropy ; Volume 23, Issue 10 , 2021 ; 10994300 (ISSN) Sioofy Khoojine, A ; Shadabfar, M ; Hosseini, V. R ; Kordestani, H ; Sharif University of Technology
    MDPI  2021
    Predicting the way diseases spread in different societies has been thus far documented as one of the most important tools for control strategies and policy-making during a pandemic. This study is to propose a network autoregressive (NAR) model to forecast the number of total currently infected cases with coronavirus disease 2019 (COVID-19) in Iran until the end of December 2021 in view of the disease interactions within the neighboring countries in the region. For this purpose, the COVID-19 data were initially collected for seven regional nations, including Iran, Turkey, Iraq, Azerbaijan, Armenia, Afghanistan, and Pakistan. Thenceforth, a network was established over these countries, and the... 

    Large eddy simulation of GDI single-hole and multi-hole injector sprays with comparison of numerical break-up models and coefficients

    , Article Journal of Applied Fluid Mechanics ; Volume 9, Issue 2 , 2016 , Pages 1013-1022 ; 17353572 (ISSN) Zamani, H ; Hosseini, V ; Afshin, H ; Allocca, L ; Baloo, M ; Sharif University of Technology
    Isfahan University of Technology  2016
    In the present study the fuel spray of a gasoline direct injected engine with multi-hole injector is simulated. Simulation inputs data, injection flow rate and spray cone angle are obtained from previous experimental studies. Log-normal distribution with different standard deviation is used for initial droplet size as the primary break-up model in order to reach the agreement between experimental and calculated spray tip penetration. As the first step, only one plume of spray injected into a quiescent air environment is simulated and validated by varying break-up model and standard deviation. Then, with coefficient obtained from the single jet simulation all six spray jets are simulated... 

    Investigation of the effect of reformer gas on PRFs HCCI combustion based on exergy analysis

    , Article International Journal of Hydrogen Energy ; Volume 41, Issue 7 , 2016 , Pages 4278-4295 ; 03603199 (ISSN) Neshat, E ; Saray, R. K ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2016
    Lack of a direct method to control combustion timing is one of the main disadvantages of homogeneous charge compression ignition (HCCI) engines. Fuel blending, in which two fuels with different auto-ignition characteristics are blended, can be used to control combustion timing. Utilizing different additives is another method for HCCI combustion control. The aim of this research is investigation on the effect of reformer gas addition on the availability terms in HCCI engines fueled with primary reference fuels (PRFs). A multi zone model (MZM) coupled with a semi detailed chemical kinetics mechanism is used for calculation of different terms of exergy analysis. Heat and mass transfer between... 

    Effect of reformer gas blending on homogeneous charge compression ignition combustion of primary reference fuels using multi zone model and semi detailed chemical-kinetic mechanism

    , Article Applied Energy ; Volume 179 , 2016 , Pages 463-478 ; 03062619 (ISSN) Neshat, E ; KhoshbakhtiSaraya Saray, R ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2016
    This study mainly aims to investigate the effect of reformer gas (RG) addition on the performance of homogeneous charge compression ignition (HCCI) engines using a multi zone model. The developed model is validated using a wide range of experimental data of a cooperative fuel research engine. Blended fuels of isooctane and n-heptane, known as primary reference fuels, with different octane numbers are used as the main engine fuel. A semi detailed chemical-kinetic mechanism containing 101 species and 594 reactions is used to simulate the combustion of blended fuels. The study is performed with different percentages of RG (0–30%). The results show that RG reduces the rate of some H abstraction... 

    Seasonal trends, chemical speciation and source apportionment of fine PM in Tehran

    , Article Atmospheric Environment ; Volume 153 , 2017 , Pages 70-82 ; 13522310 (ISSN) Arhami, M ; Hosseini, V ; Zare Shahne, M ; Bigdeli, M ; Lai, A ; Schauer, J. J ; Sharif University of Technology
    Elsevier Ltd  2017
    Frequent air pollution episodes have been reported for Tehran, Iran, mainly because of critically high levels of fine particulate matter (PM2.5). The composition and sources of these particles are poorly known, so this study aims to identify the major components and heavy metals in PM2.5along with their seasonal trends and associated sources. 24-hour PM2.5samples were collected at a main residential station every 6 days for a full year from February 2014 to February 2015. The samples were analyzed for ions, organic carbon (including water-soluble and insoluble portions), elemental carbon (EC), and all detectable elements. The dominant mass components, which were determined by means of... 

    The effect of diethyl ether addition on performance and emission of a reactivity controlled compression ignition engine fueled with ethanol and diesel

    , Article Energy Conversion and Management ; Volume 174 , 2018 , Pages 779-792 ; 01968904 (ISSN) Mohebbi, M ; Reyhanian, M ; Hosseini, V ; Said, M. F. M ; Abdul Aziz, A ; Sharif University of Technology
    Elsevier Ltd  2018
    Reactivity controlled compression ignition has been introduced to implement controllable, clean, and high thermal efficiency without undermining the advantages of premixed combustion. However, simultaneous auto-ignition introduced by reactivity controlled combustion challenges the combustion under higher load operations. This experimental study incorporates a dual phase heat release concept with the purpose of improving the performance of reactivity controlled compression ignition engine. Different ratios of ethanol/diethyl-ether blends (from 0% to 40% diethyl ether and 70% premixed ratio) were applied to a light duty diesel engine at various combustion timings and engine loads. The diesel... 

    Modeling the formation of traditional and non-traditional secondary organic aerosols from in-use, on-road gasoline and diesel vehicles exhaust

    , Article Journal of Aerosol Science ; Volume 124 , 2018 , Pages 68-82 ; 00218502 (ISSN) Esmaeilirad, S ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2018
    In this study, we implement a numerical model to predict secondary organic aerosol (SOA) formation from semi- and intermediate-volatility organic compounds emitted from in-use gasoline and diesel vehicles. The model is formulated based on the volatility basis set (VBS) approach, and it accounts for OH oxidation of unspeciated low-volatility organics, which are classified by their volatility. This model incorporates SOA formation data from smog chamber and emission measurements of vehicle exhaust in a Hybrid framework to calculate the contribution of both traditional and non-traditional SOA precursors to total SOA formation observed in photo-oxidation experiments. Emission and SOA formation... 

    A novel regression imputation framework for Tehran air pollution monitoring network using outputs from WRF and CAMx models

    , Article Atmospheric Environment ; Volume 187 , 2018 , Pages 24-33 ; 13522310 (ISSN) Shahbazi, H ; Karimi, S ; Hosseini, V ; Yazgi, D ; Torbatian, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Missing or incomplete data in short or long intervals is a common problem in measuring air pollution. Severe issues may arise when dealing with missing data for time-series prediction schemes or mean analysis. This study aimed to develop a new regression imputation framework to impute missing values in the hourly air quality data set of Tehran and enhance the applicability of Tehran Air Pollution Forecasting System (TAPFS). The proposed framework was designed based on three types of features including measurements of other stations, WRF and CAMx physical models. In this framework, elastic net and neuro-fuzzy networks were efficiently combined in a two-layer structure. The framework was... 

    Seasonal trends in the composition and sources of PM2.5 and carbonaceous aerosol in Tehran, Iran

    , Article Environmental Pollution ; Volume 239 , 2018 , Pages 69-81 ; 02697491 (ISSN) Arhami, M ; Zare Shahne, M ; Hosseini, V ; Roufigar Haghighat, N ; Lai, A. M ; Schauer, J. J ; Sharif University of Technology
    Elsevier Ltd  2018
    Currently PM2.5 is a major air pollution concern in Tehran, Iran due to frequent high levels and possible adverse impacts. In this study, which is the first of its kind to take place in Tehran, composition and sources of PM2.5 and carbonaceous aerosol were determined, and their seasonal trends were studied. In this regard, fine PM samples were collected every six days at a residential station for one year and the chemical constituents including organic marker species, metals, and ions were analyzed by chemical analysis. The source apportionment was performed using organic molecular marker-based CMB receptor modeling. Carbonaceous compounds were the major contributors to fine particulate mass... 

    Various effects of reformer gas enrichment on natural-gas, iso-octane and normal-heptane HCCI combustion using artificial inert species method

    , Article Energy Conversion and Management ; Volume 159 , March , 2018 , Pages 7-19 ; 01968904 (ISSN) Reyhanian, M ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2018
    Reformer gas (syngas) addition to main fuel is a practical solution for combustion timing control in HCCI engines. This study emphasizes the understanding of various effects of reformer gas (RG) addition, with composition of 75%vol H2 and 25%vol CO, in HCCI combustion by developing an artificial inert species method and using a detailed chemical kinetics multi-zone model. Three fuels (iso-octane, n-heptane, and natural gas) with different autoignition characteristics were used in this study. The developed multi-zone model was validated for mentioned fuels at various percentages of RG using six experimental cases of a single-cylinder CFR engine. The results showed that increasing reformer gas... 

    Performance and emissions of a reactivity controlled light-duty diesel engine fueled with n-butanol-diesel and gasoline

    , Article Applied Thermal Engineering ; Volume 134 , April , 2018 , Pages 214-228 ; 13594311 (ISSN) Mohebbi, M ; Reyhanian, M ; Hosseini, V ; Muhamad Said, M. F ; Aziz, A. A ; Sharif University of Technology
    Elsevier Ltd  2018
    Reactivity Controlled Compression Ignition can be extended over a wide spectrum of fuels and is anticipated as a promising strategy in meeting current and future emission regulations. In this study, the effect of n-butanol addition on combustion characteristics and emissions in a reactivity controlled engine was investigated experimentally. Different ratios of butanol-diesel blends at different settings of EGR and premixed ratios were applied to a light duty diesel engine. The butanol-diesel blends were directly injected into the combustion chamber while gasoline was injected at the intake port. Combustion phasing was maintained at 2.7 °CA for all of test points by adjusting fuel injection... 

    Black carbon and PM2.5 monitoring campaign on the roadside and residential urban background sites in the city of Tehran

    , Article Atmospheric Environment ; Volume 218 , 2019 ; 13522310 (ISSN) Taheri, A ; Aliasghari, P ; Hosseini, V ; Sharif University of Technology
    Elsevier Ltd  2019
    Fine particulate matter characterized as PM2.5 is the most important criteria air pollutant in the city of Tehran. Tehran is one of the most polluted cities of the Middle East based on annual mean PM2.5 concentrations. Tehran emission inventory shows the large contribution of mobile sources to the total particles. PM2.5 source apportionment studies show large fraction of black carbon (BC) in the total mass of PM2.5, especially during the cold seasons. BC is the product of incomplete combustion that is mainly derived from diesel engines and rich-burned gasoline carburetor engines on scooters and light-duty vehicles. The present study shows the results of a large experimental campaign in which... 

    Short-term associations between daily mortality and ambient particulate matter, nitrogen dioxide, and the air quality index in a Middle Eastern megacity

    , Article Environmental Pollution ; Volume 254 , 2019 ; 02697491 (ISSN) Amini, H ; Trang Nhung, N. T ; Schindler, C ; Yunesian, M ; Hosseini, V ; Shamsipour, M ; Hassanvand, M. S ; Mohammadi, Y ; Farzadfar, F ; Vicedo Cabrera, A. M ; Schwartz, J ; Henderson, S. B ; Künzli, N ; Sharif University of Technology
    Elsevier Ltd  2019
    There is limited evidence for short-term association between mortality and ambient air pollution in the Middle East and no study has evaluated exposure windows of about a month prior to death. We investigated all-cause non-accidental daily mortality and its association with fine particulate matter (PM2.5), nitrogen dioxide (NO2), and the Air Quality Index (AQI) from March 2011 through March 2014 in the megacity of Tehran, Iran. Generalized additive quasi-Poisson models were used within a distributed lag linear modeling framework to estimate the cumulative effects of PM2.5, NO2, and the AQI up to a lag of 45 days. We further conducted multi-pollutant models and also stratified the analyses by...