Sharif Digital Repository

This study proposes a scheme for optimizing the extraction of Damask rose essential oil under supercritical conditions. The effects of temperature, pressure, and static time on the extraction process were investigated using response surface methodology (RSM). The results showed that increasing pressure and static time had a positive effect on extraction, while increasing temperature had a negative effect. The optimal conditions for extraction were found to be 45 °C, 180 bar, and 180 min, with an efficiency of approximately 92% and a content of 54.2% for 2-phenylethanol. The extraction process was modeled using Peng–Robinson equations based on equilibrium data, with values of kij and lij... 

An industrial-scale reactor for ethylene production was modeled using the oxidative dehydrogenation of ethane (ODHE) in a multi-tubular reactor system, examining a variety of parameters affecting reactor performance. The model showed that a double-bed multi-tubular reactor with intermediate air injection scheme was superior to a single-bed design, due to the increased ethylene selectivity while operating under lower oxygen partial pressures. The optimized reactor length for 100% oxygen conversion was theoretically determined for both reactor designs. The use of a distributed oxygen feed with a limited number of injection points indicated a significant improvement on the reactor performance... 

This study investigated the mode I fracture behavior of double cantilever beam (DCB) epoxy adhesive joints with similar adherends on the both sides (i.e., aluminum-aluminum or copper-copper) at different strain rates; i.e., quasi-static (∼10−3 s−1), low (∼7 s−1) and intermediate (∼14 s−1) rates. The fracture energy of the DCB joint in Al-adhesive-Al specimens decreased (i.e., by ∼62%, p = 0.0013) with an increase in the applied strain rate from quasi-static to low values, while it remained almost unchanged with further increase of stain rate to intermediate range (p > 0.05). For Cu-adhesive-Cu cases, however, the fracture energy was found to be almost insensitive to the applied strain rate... 

The latest research studies on Steel Plate Shear Walls (SPSWs) suggest that the use of large-sized openings in infill plates calls for the use of heavy stiffeners or special measures for ensuring system stability. This study explores the effect of introduction of large unstiffened openings in SPSWs. A number of single story SPSWs with solid infill plates and their corresponding models with unstiffened openings are designed and analyzed numerically. In addition, this study provides a comparison of the experimental and numerical results obtained from the finite element models of SPSWs with openings. The results indicate the acceptable behavior of the specimens even at high levels of drift in... 

The effect of condensate blockage on the pressure drop near the well bore has been studied. Two types of single well simulations have been conducted and pressure drop due to condensate blockage has been quantified based on variation of gas relative permeabilities in near well bore area. The relationship of condensate banking pressure drop, gas rate and reservoir quality has been presented. It is shown that for a poor reservoir quality, condensate blockage can increase the pressure drop up to 200% of the pressure drop in the tubing  

Fast pose estimation (PE) plays a vital role for agile autonomous robots in successfully carrying out their tasks. While Global Navigation Satellite Systems (GNSS) such as Global Positioning System (GPS) have been traditionally used along with Inertial Navigation Systems (INS) for PE, their viability is compromised in indoor and urban environments due to their low update rates and inadequate signal coverage. Visual-Inertial Odometry (VIO) is gaining popularity as a practical alternative to GNSS/INS systems in GNSS-denied environments. Among various VIO-based methods, the Multi-State Constraint Kalman Filter (MSCKF) has garnered significant attention due to its robustness, speed and accuracy.... 

With the increasing tendency to use the Additive manufacturing (AM) process and especially the Selective laser melting (SLM), improving the properties of the AM part becomes essential. Among the governing parameters for producing an AM part, part build orientation (PBO) is the most important one that can improve the properties by an appropriate adjusting. In this study, the surface roughness, build time, and mechanical properties of AM part are optimized and the results will be selected based on each objective function (OF) importance. To achieve this purpose, the OF for each property is derived from the literature. Then the OFs meta-modeled through the Kriging method and sample points of... 

An industrial scale propylene production via oxidative dehydrogenation of propane (ODHP) in multi-tubular reactors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows. Herein, a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence olefin over V2O5/γ-Al2O3 catalyst was presented. Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions, gas process and coolant temperatures, as well as other parameters affecting the reactor performance such... 

Realistic simulation of tool-tissue interactions can help to develop more effective surgical training systems and simulators. This study uses a finite element and meshless modeling approach to simulate the grasping procedure of a large intra-abdominal organ, i.e. a kidney, during laparoscopic surgery. Results indicate that the accuracy of the meshless method is comparable with that of the finite element method, with root mean square errors in the range of 0.8 to 2.3 mm in different directions. For the model presented in this study, the computational cost of the meshless method was much less than that of the finite element model  

Silk fibroin (SF) as a natural biopolymer holds great potential in biomedical research because of its biocompatibility, easy processability and high strength properties. However, slow gelation time has narrowed its applications, specifically in cell-laden microparticle production due to insufficient crosslinkable moieties. This study aimed to develop cell-laden silk fibroin-phenol (SF-Ph) microparticle through co-flow microfluidic system using SF conjugated Ph moieties whereas covalent crosslinking is mediated with horseradish peroxidase (HRP) in the presence of hydrogen peroxide (H2O2). For this, the SF-Ph was synthesized through carbodiimide condensation crosslinking reaction. Aqueous...