Scientia Iranica
Volume:30 Issue: 3, May-June 2023

This research presents a novel extended thermodynamic analysis method which helps to answer the question that, the improvement of which equipment in a thermodynamic cycle is in priority. This novel analysis has 3 parts including extended energy, extended entropy, and extended exergy analyses. As a case study, a low-temperature geothermal Kalina cycle system-34 was analyzed. The results were compared with the outcomes of conventional and advanced exergy analyses. Conventional exergy analysis indicated that the condenser, evaporator, and turbine have the largest exergy destruction, respectively while according to advanced exergy analysis, condenser, turbine, and LTR have the highest priority for improvement, respectively. The improvement priority using the presented novel extended analysis was also given to condenser, turbine, and LTR, respectively which is the same as the results of advanced exergy while the presented novel method is less complicated compared to the advanced exergy analysis.

Best cancer treatment is the one which reduces the tumor’s density in minimum time with less side effects, considering the input limitations. In this paper, a tracking controller was designed to achieve the mentioned objectives, simultaneously. An ordinary differential equations (ODEs)-based mathematical model of a human’s body under chemovirotherapy was selected, which includes the uninfected and infected tumor cells, free viruses, immune cells, and a chemotherapeutic drug. Stability analysis was used to determine the sensible equilibrium points. For tracking purposes, a servo controller based on the entire eigenstructure assignment (EESA) approach was applied to the model, continuously and discretely. By regulating the command input properties, optimal treatment duration with limited drug dosage and virus dosage was determined. The results indicate that the discrete controller performs smoother than the continuous controller. In the discrete controller, optimum time interval for the injection of drugs and viruses was determined to propose an optimal treatment schedule.

In this research work, two different compositions of MR fluid samples with 24 and 30 percentage (%) volume fraction of carbonyl iron (CI) particles are prepared. Prepared MR fluid (MRF) samples contain carbonyl iron particles as a dispersive medium, silicone oil as a carrier fluid, and white lithium grease as an anti-settling agent. Influence of oscillating driving frequency, strain amplitude, magnetic field, and the percentage of CI particle on the rheological properties of the MR fluid samples are presented. Storage modulus and loss factor equations are estimated from the rheometry results using a linear regression method. The properties of MR fluid samples are taken to design and model the sandwich beams using ANSYS ACP software, where carbon epoxy composite material is used as the face layer and MR fluid as the core material. Modal, harmonic, and transient analysis studies have been conducted on all the modelled sandwich beams. Influence of MR fluid core material thickness, face layer thickness, CI particle volume percentage in the prepared MR fluid sample, and magnetic field on the vibrational response of the sandwich beams have been presented. Carbon-epoxy composites with an in-house made MRF sandwich beam has shown some significant results in the vibrational response.

The aim of this study is to investigate how the weibull distribution function is compatible with the wind data in the offshore regions. Especially with the increase in energy demand and the advancement of technology, the importance of wind energy has increased. Many academic studies on wind energy have been conducted and are being conducted at the same time. Determination of wind energy potential offshore and making investments in this area have accelerated today. Although many studies have been made in the field of wind energy, it is not sufficiently benefited from above-sea wind energy. The compatibility of wind data with Weibull Distribution Function (WDF) on land has been investigated in many academic studies and the results have been evaluated. However, the compatibility of the offshore wind data with the WDF has not been investigated sufficiently and there are steps to be taken in this regard. In this study, a point was selected in Iskenderun Gulf to examine the compatibility of offshore wind data with WDF function. In this study, six different methods are used to determine the parameters of the WDF and their performance are evaluated in different error analysis tests.

Considering the risk of infection in surgeries, maintaining an acceptable indoor air quality in the operating rooms (ORs) to ensure the health and safety of patients and surgical team is very essential. Since airflow is one of the primary mechanisms for transmitting of infections and pollution, it is crucial to examine the air distribution systems in the ORs. In the present study the effect of turbulent and laminar airflow (TAF/ LAF) systems on the air and CO2 distribution in an OR was examined. The effects of inlet and outlet configurations were evaluated for seven different models. The results indicated that the LAF systems is superior over TAF systems. Based on the findings, the LAF with the air curtain configuration brings about the minimum CO2 concentration level in the OR. The results showed that LAF with the air curtain model is able to decrease the CO2 concentration by about 64.66% and 88.96% on central plane, which passes along the body patient on 1.14 m and 1.7 m above the floor, respectively compared to the existing model.

The current study investigates the two-phase turbulentnanofluid flow insidein a heat exchanger tube equipped with a novel type of conical turbulators having two parallel rows of holes, for first time.The range of Reynolds number was between 4000and20000 under turbulent flow regime and uniform wall temperature condition.Water is considered as the base fluid and TiO2 nanoparticles with volume fractions of0–2.5% are added as the second phase to the base fluid.The effect of number of the conical insert turbulators, number of the holes and volume fraction of the nanoparticles on flow field,average Nusselt number,friction factor and performance evaluation criterion(PEC) have been numerically investigated.The results show that the proposed turbulators create vortices and recirculating currents that have significant effect on heat transfer.As number ofthe turbulators increases,Nusselt number increases obviously.However,the presence of holes also reduces the friction factor andpressure drop that is related to lower resistance in the flow path.In general,the use of perforated conical turbulators improves PEC by creating controlled turbulent flows.Onthe otherhand,the useof added nanoparticles also enhances heat transfer.The presented turbulators increase PEC up to43% compared to the smooth tube,if the parameters are determined properly.The maximum PEC of1.43 is obtained at M=8,N=4 and Re=4100,which shows good performance compared to othertypes of turbulators.

The aim of deploying hybrid nanofluids is to optimize the heat transfer features of the model under consideration. Hybrid nanofluids contain composite nanoparticles, which improve thermal conductivity. Here, Silver (Ag) and Graphene oxide (Go) are used as nanoparticles with kerosene oil as a base fluid. The impact of Ohmic heating, viscous dissipation, and thermal radiation are taken to model the problem of steady flow over a stretching/shrinking geometry. The governing equations are numerically solved by a built-in scheme, bvp4c in Matlab. Moreover, the existence of dual solutions is found for a given range of pertinent parameters. The impact of the melting heat transfer parameter is heeded on the coefficient of skin friction and Nusselt number for both hybrid nanofluid and nanoparticles. A comparison is established with the pre-existing results, which is in good agreement. It is noted that the values of the coefficient of skin friction for the stable branch decrease for a particular range of shrinking parameter; however, for the lower branch opposite trend is observed. The magnetic force decreases the flow field and energy distribution for the upper branch; however, enhances for lower branch.