Study of photochemical and sonochemical processes efficiency for degradation of dyes in aqueous solution

Afshin Maleki,Amir Hossein Mahvi,Roya Ebrahimi,Yahya Zandsalimi 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.6

The degradation of two commercially available dyestuffs (C.I. Reactive Black 5 and C.I. Disperse Orange 25) by ultraviolet radiation (UV), ultrasonic irradiation (US), UV/H2O2 and US/H2O2 processes was investigated in a laboratory-scale batch photoreactor equipped with a 55 W immersed-type low-pressure mercury vapor lamp and a sonoreactor with low frequency (42 kHz) plate type transducer at 170W of acoustic power. The toxicity was also evaluated in acute toxicity studies using Daphnia magna. Results showed that color removal efficiencies by US and US/H2O2processes were negligible for both dyes. Almost complete disappearance of Reactive Black 5 (97.9%) in UV/H2O2 process was possible after 5 min of irradiation. The maximum color removal efficiency of Disperse Orange 25 after 10min of irradiation, however, was only 9.2% and reached a maximum value of 41% after 120 min of irradiation. Pseudofirst order kinetics with respect to dyestuffs concentrations was found to fit all the experimental data. The results clearly showed that both dyes examined were toxic to D. magna and resulted in quite low LC50 values.

3D finite element modelling of composite connection of RCS frame subjected to cyclic loading

Mohammad Hossein Habashizadeh Asl,Mohammad Reza Chenaglou,Karim Abedi,Hassan Afshin 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.3

Composite special moment frame is one of the systems that are utilized in areas with low to high seismicity to deal with earthquake forces. Composite moment frames are composed of reinforced concrete columns (RC) and steel beams (S); therefore, the connection region is a combination of steel and concrete materials. In current study, a three dimensional finite element model of composite connections is developed. These connections are used in special composite moment frame, between reinforced concrete columns and steel beams (RCS). Finite element model is discussed as a most reliable and low cost method versus experimental procedures. Based on a tested connection model by Cheng and Chen (2005), the finite element model has been developed under cyclic loading and is verified with experimental results. A good agreement between finite element model and experimental results was observed. The connection configuration contains Face Bearing Plates (FBPs), Steel Band Plates (SBPs) enveloping around the RC column just above and below the steel beam. Longitudinal column bars pass through the connection with square ties around them. The finite element model represented a stable response up to the first cycles equal to 4.0% drift, with moderately pinched hysteresis loops and then showed a significant buckling in upper flange of beam, as the in test model.

Photo-oxidation of phenol in aqueous solution: Toxicity of intermediates

Amir Hossein Mahvi,Afshin Maleki,Mahmood Alimohamadi,Azar Ghasri 한국화학공학회 2007 Korean Journal of Chemical Engineering Vol.24 No.1

The effects of orthognathic surgery on auditory function

Farhad Ghorbani,Hossein Danesteh,Afshin Khoramnia,Saeid Tavanafar 대한악안면성형재건외과학회 2021 Maxillofacial Plastic Reconstructive Surgery Vol.43 No.-

BackgroundOrthognathic surgery is widely used in treating functional and skeletal problems. Any surgical procedure could cause side effects. ObjectivesThis study aimed to evaluate the potential changes in orthognathic surgery on the hearing function of patients. Materials and methodsThirty-one orthognathic surgery candidates were recruited in this study. Patients underwent either single or double jaw surgery. Pure tone audiometry (PTA), tympanometry, and Eustachian Tube Dysfunction Test (ETFT) were performed postoperatively at 24 h, 6 weeks, and 6 months after surgery. Patients were tabulated based on the type of maxilla and mandibular surgical movements (vertical and horizontal). ResultsPTA evaluation, based on horizontal or vertical movements, did not show significant differences, although vertical movements resulted in less change in hearing threshold. In other words, no significant changes occurred in patients’ hearing threshold after surgery. No significant difference was also observed between horizontal and vertical movements in the results of tympanometry. Negative changes were found in the results of ETFT in vertical movements, which returned to pre-surgery values in the final test. ConclusionsThe risk of minor changes in hearing function is probable during the first week after orthognathic surgery, but these negative changes will either totally fade or remain negligible. Patients gave informed consent preoperatively, and reassurance postoperatively is prudent.

An analysis of carbone monoxide distribution in large tunnel fires

Atta Sojoudi,Hossein Afshin,Bijan Farhanieh 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.5

Fire events and the related toxicants such as CO are responsible for many fatalities in the current century. These hazardous events aremuch more dangerous when they occur in enclosed spaces. In the present study, a theoretical relation is developed for horizontal distributionof CO in a large tunnel fire. Then, the developed criterion is used to study the effect of some rudimentary parameters such as the heatrelease rate (HRR) of fire and tunnel's aspect ratio (AR) on CO and temperature stratification. Theoretical results of various heat releaserates and aspect ratios for horizontal distribution of CO are compared with numerical results using fire dynamics simulator (FDS5.5). It isfound that big fires have higher rates of CO concentration decay in comparison to the smaller ones due to higher air entrainment into thetravelling plume. It is indicated that the smoke travelling at higher values of tunnel AR, dilutes faster. Moreover, using FDS5.5, the relevantvariations in temperature and CO concentration are discussed for tunnel angles ranging from -20˚ to 20˚.

Self-pressurization analysis of the natural circulation integral nuclear reactor using a new dynamic model

Ali Farsoon Pilehvar,Mohammad Hossein Esteki,Afshin Hedayat,GHOLAM REZA ANSARIFAR 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.5

Self-pressurization analysis of the natural circulation integral nuclear reactor through a new dynamicmodel is studied. Unlike conventional pressurized water reactors, this reactor type controls the systempressure using saturated coolant water in the steam dome at the top of the pressure vessel. Selfpressurizationmodel is developed based on conservation of mass, volume, and energy by predictingthe condensation that occurs in the steam dome and the flashing inside the chimney using the partialdifferential equation. A simple but functional model is adopted for the steam generator. The obtainedresults indicate that the variable measurement is consistent with design data and that this new model isable to predict the dynamics of the reactor in different situations. It is revealed that flashing andcondensation power are in direct relation with the stability of the system pressure, without whichpressure convergence cannot be established.

Risk factors of inadequate emergence following general anesthesia with an emphasis on patients with substance dependence history

Makarem Jalil,larijani Amir Hossein,Eslami Babak,Jafarzadeh Afshin,Karvandian Kasra,Mireskandari Seyed Mohammad 대한마취통증의학회 2020 Korean Journal of Anesthesiology Vol.73 No.4

Background: This study aims to define the incidence and risk factors of both emergence agitation and hypoactive emergence in adult patients and substance-dependent patients following general anesthesia to elaborate on the risk factors and precise management of them. Methods: The study recruited 1,136 adult patients who received elective surgeries under general anesthesia for this prospective observational study. Inadequate emergence was determined according to the Richmond Agitation-Sedation Scale (RASS). Emergence agitation was defined as a RASS ≥ +1 point, and hypoactive emergence was defined as a RASS ≤ –2 points. Subgroup analyses were then conducted on patients with substance dependence. Results: Inadequate emergence in the post-anesthesia care unit (PACU) occurred in 20.3% of patients, including 13.9% with emergence agitation and 6.4% with hypoactive emergence. Ninety-five patients had a history of substance dependence. Compared to divorced patients, never-married and presently married patients, who underwent gynecological and thoracic surgeries, had a lower risk of agitation. Neurologic disorders, intraoperative blood loss, intraoperative morphine, and PACU analgesic drug administration were associated with increased agitation risk. Hypertension and psychological disorders, intraoperative opioids, and PACU Foley catheter fixation were associated with increased hypoactive emergence risk. Substance-dependent patients had higher risk for agitation (21.1%, P = 0.019) and hypoactive emergence (10.5%, P = 0.044). Conclusions: Inadequate emergence in PACU following general anesthesia is a significant problem correlated with several perioperative factors. Patients with a history of substance dependence appear to be more at risk of inadequate emergence than the general population.

Investigation of heat transfer of the frame of entrance door encompassing phase change materials through computational fluid dynamics schemes

Solghar Alireza Arab,Ahsaei Seyed Hossein,Iranmanesh Afshin,Dehaj Mohammad Shafiey 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.8

Embedment of phase change materials (PCMs) in buildings elements is a technique to lower the heating and cooling demands. In the present study, a frame of entrance doors filled with the PCMs was simulated for a sunny summer day condition of Rafsanjan city in Iran. It was assumed that the frame is subjected to the indoor and outdoor temperature and solar radiation. The simulation was carried out through 2-D finite element method taking into account heat and mass transfer in the PCM. A parametric study was conducted to investigate the type of PCMs, the volume PCMs as well as their positions in the frame. The results were compared with a common frame filled with air. The obtained findings showed that RT-25 is more effective than capric acid, paraffin and P116. Maximum reduction of heat flux was observed to be 37.72% for the frame filled with RT-25 when its outside walls were in contact with the PCM. The results also reveal that the incorporation of the PCM is effective for passive thermal storage.

Experimental investigation of the effects of surfactant on the dynamics of formation process of liquid drops

Peyman Dastyar,Moloud Sadat Salehi,Bahar Firoozabadi,Hossein Afshin 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-

In the present study, the formation of surfactant-laden viscous drops in ambient air is experimentallyinvestigated using a high-speed digital camera. The mixtures of 90%, 92.5%, and 95% glycerol by weight inwater containing various concentrations of sodium dodecyl sulfate are chosen as the drop phasefluid. The focus of this work is to investigate the effects of concentration of surfactant dissolved in solutionswith different viscosities, on physical and geometrical parameters related to drop formation process,such as the drop elongation, minimum neck thickness, formation time, and the drop volume. Theformation of satellite drops and the influence of surfactant concentration on their size are also studied. The obtained results indicate that increasing the surfactant concentration and the viscosity of drop phasefluid, slows down the necking process and causes the drop detachment length to increase. The entireprocess of drop formation is divided into two stages, and it was found that adding surfactant to thesolutions has inverse effects on the duration of these two stages. It was also shown that surfactantaddition contributes to an increase in the size of the satellite drop due to generation of Marangonistresses on the surface of the drop's neck.

Engineered Probiotics for the Management of Congenital Metabolic Diseases: A Systematic Review

Meisam Barati,Erfan Mosharkesh,Amir Hossein Tahmassian,Maryam Khodaei,Masoumeh Jabbari,Ali Kalhori,Mohsen Alipour,Afshin Abdi Ghavidel,Sajad Khalili-Moghadam,Anwar Fathollahi,Sayed Hossein Davoodi 한국식품영양과학회 2024 Preventive Nutrition and Food Science Vol.29 No.1

Engineered probiotics (EPs) can be used to treat/manage chronic and congenital diseases. However, to the best of our knowledge, no systematic review has evaluated the effects of EPs on congenital metabolic disorders in murine models and human subjects. Thus, the present study systematically reviewed interventional studies that assessed the effects of EPs on congenital metabolic disorders. PubMed, Web of Science, and Scopus databases were searched up to February 2023 to retrieve related publications. Seventy-six articles were obtained in the primary step. After screening the titles/abstracts based on the inclusion and exclusion criteria, 11 papers were included. Finally, only seven articles were included after performing full-text evaluation. The included articles evaluated the effects of EPs on managing phenylketonuria (PKU, n=4) and hyperammonemia (n=3). Moreover, these studies examined mice and/or rats (n=6), monkeys (n=1), and humans (n=2). Studies on EPs and hyperammonemia revealed that some wild strains such as Lactobacillus plantarum have an innate ammonia-hyper-consuming potential; thus, there was no need to manipulate them. However, manipulation is needed to obtain a phenylalanine- metabolizing strain. In conclusion, EPs can be used to manage or treat congenital metabolic diseases including PKU.