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921.
922.
Amin Montazeri Ehsan Bahmanpour Majid Safarabadi 《Advanced Engineering Materials》2023,25(17):2300273
Cellular hexagonal (conventional) and re-entrant (auxetic) honeycombs are applicable in automotive, construction, and protective engineering. Auxetic structures own excellent energy absorption and flexural behavior due to their special deformation under loading. This work explores the performance of additively manufactured polylactic acid (PLA)- and thermoplastic polyurethane (TPU)-based hexagonal and re-entrant honeycombs under flexural loading via experimental three-point bending (TPB) tests and finite-element analysis (FEA). 3D-printed conventional and auxetic cellular structures are filled with polyurethane (PU) foam and their energy absorption capacity and flexural modulus are compared with hollow structures. The results reveal that TPU-based structures’ energy absorption capacity and flexural modulus improve significantly, whereas the PLA-based structures’ performance deteriorates when filled with PU foam. Moreover, re-entrant honeycombs are better reinforced with foam in comparison to the hexagonal honeycombs, as the re-entrant's unit cell is more spacious than the hexagonal unit cell. Finally, parametric studies are performed via FEA to investigate the influence of geometric parameters of structures and flexural loading setup on the performance of the honeycombs, showing that structures with thicker struts and higher cell angle can act stiffer under TPB. The outcomes of this research indicate the promising performance of foam-filled TPU-based auxetic structures. 相似文献
923.
Seyyed Koorosh Hosseini Bahram Soltani Soulgani Jalal Foroozesh Ehsan Haji Bolouri 《Journal of surfactants and detergents》2023,26(1):83-96
Foam injection contributes to improved oil recovery through flow diversion, reduction of interfacial tension (IFT), and wettability alteration of the rock while its stability is an issue. In this article, nitrogen-foam was optimally formulated using fluorocarbon tubiguard protect (FTP) surfactant stabilized with sodium dodecyl sulfate (SDS) co-surfactant that was later experimentally considered for oil recovery in a fractured carbonate rock taken from an oil field in the Middle East. The results showed that the 5:1 volume ratio of fluorocarbon surfactant and SDS (FS51) generates a stable foaming agent with ability of changing the wettability of the carbonate rock surfaces to an intermediate gas-wet state. A series of core-flood experiments at HPHT conditions were also carried out and designed to properly represent matrix-fracture media using both a horizontally and vertically oriented setup. The oil saturated cores were flooded with nitrogen gas first followed by foam injection. It was concluded that foam can divert the gas to flow from fractures to the matrix blocks and result in a significant oil recovery. The contact angle tests that performed after core-flood experiments revealed the wettability changes of fracture surfaces from an oil-wet to a gas-wet state. This allows gas to be imbibed into the matrix blocks by capillary force and results in enhancement of ultimate oil recovery. This study revealed that trapped oil in matrixes blocks that had not been drained during the gas injection process could be produced by designing a stable foam that sustainably diverts injected fluid from fractures to matrix zone. 相似文献
924.
Farhadi Ladan Mohtashami Mahnaz Saeidi Jafar Azimi-nezhad Mohsen Taheri Ghadir Khojasteh-Taheri Roshanak Rezagholizade-Shirvan Alieh Shamloo Ehsan Ghasemi Ahmad 《Journal of Inorganic and Organometallic Polymers and Materials》2022,32(5):1637-1649
Journal of Inorganic and Organometallic Polymers and Materials - The production of silver nanoparticles (AgNPs) using chemical synthesis routes require hazardous and toxic solvents. Nowadays, there... 相似文献
925.
Yaser Khojasteh-Salkuyeh Omid Ashrafi Ehsan Mostafavi Philippe Navarri 《加拿大化工杂志》2023,101(10):5446-5459
Mitigating CO2 emissions from industries and other sectors of our economy is a critical component of building a sustainable economy. This paper investigates two different methanol synthesis routes based on CO2 utilization (CO2 capture and utilization [CCU], and tri-reforming of methane [TRM]), and compares the results with the conventional methanol production using natural gas as the feedstock (NG-MeOH). A comprehensive techno-economic analysis (TEA) model that includes the findings of the life cycle assessment (LCA) models of methanol production using various CO2 utilization pathways is conducted. Economic analysis is conducted by developing a cost model that is connected to the simulation models for each production route. Compared to the conventional process (with a GHG emission of 0.6 kg CO2/kg MeOH), the lifecycle GHG reduction of 1.75 and 0.41 kg CO2/kg MeOH are achievable in the CCU and TRM pathways, respectively. Furthermore, the results indicate that, under current market conditions and hydrogen production costs, methanol production via CO2 hydrogenation will result in a cost approximately three times higher than that of the conventional process. The integrated TEA–LCA model shows that this increased cost of production equates to a required life cycle GHG reduction credit of $279 to $422 per tonne of CO2 utilized, depending on construction material and selected pathway. Additionally, when compared to the CO2 hydrogenation route, the tri-reforming process (TRM-MeOH) can result in a 42% cost savings. Furthermore, a minimum financial support of $56 per tonne utilized CO2 will be required to make the TRM-MeOH process economically viable. 相似文献
926.
Sayed Aref Ghoreishee Mohammad Shahrokhi Ehsan Vafa Ali Moradvandi 《International Journal of Adaptive Control and Signal Processing》2023,37(3):666-693
This paper investigates design of an adaptive fixed-time fault-tolerant decentralized controller for a class of uncertain multi-input multi-output (MIMO) switched large-scale non-strict interconnected systems under arbitrary switching subject to unknown control directions, quantized nonlinear inputs, actuator failures unknown external disturbances, and unmodeled dynamics. In addition to interconnected terms, time-varying delayed interconnected terms have been considered in the system model which makes it more general than previous works in the literature. The proposed controller can handle switched systems with unknown switching signal and different types of input nonlinearities including, saturation, backlash, and dead-zone. The singularity problem in designing the fixed time controller has been solved. The quantizer and actuators fault parameters are assumed to be unknown. The Razumikhin lemma has been used to deal with the delayed interconnected terms. To cope with the system unknown dynamics, neural networks (NNs) have been applied and by updating the maximum norms of the networks weight vectors the computational load has been reduced. The explosion of complexity occurring in the traditional back-stepping technique has been avoided by applying dynamic surface control (DSC). Finally, by defining an appropriate common Lyapunov function (CLF), fixed-time convergence of system outputs and the closed-loop system stability have been established. The effectiveness of the proposed controller has been shown via simulation study. 相似文献
927.
Minmin Shao Ashkan Bigham Satar Yousefiasl Cynthia K. Y. Yiu Yarabahally R. Girish Matineh Ghomi Esmaeel Sharifi Serap Sezen Ehsan Nazarzadeh Zare Ali Zarrabi Navid Rabiee Ana Cláudia Paiva-Santos Serena Del Turco Baolin Guo Xiangdong Wang Virgilio Mattoli Aimin Wu 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(19):2207057
Oxidative damage and infection can prevent or delay tissue repair. Moreover, infection reinforces reactive oxygen species (ROS) formation, which makes the wound's condition even worse. Therefore, the need for antioxidant and antibacterial agents is felt for tissue regeneration. There are emerging up-and-coming biomaterials that recapitulate both properties into a package, offering an effective solution to turn the wound back into a healing state. In this article, the principles of antioxidant and antibacterial activity are summarized. The review starts with biological aspects, getting the readers to familiarize themselves with tissue barriers against infection. This is followed by the chemistry and mechanism of action of antioxidant and antibacterial materials (dual function). Eventually, the outlook and challenges are underlined to provide where the dual-function biomaterials are and where they are going in the future. It is expected that the present article inspires the designing of dual-function biomaterials to more advanced levels by providing the fundamentals and comparative points of view and paving the clinical way for these materials. 相似文献
928.
Dr. Muhammad Ehsan Dr. Haoqing Wang Dr. Satoshi Katsube Chastine F. Munk Dr. Yang Du Taeyeol Youn Soyoung Yoon Prof. Bernadette Byrne Prof. Claus J. Loland Prof. Lan Guan Prof. Brian K. Kobilka Prof. Pil Seok Chae 《Chembiochem : a European journal of chemical biology》2022,23(7):e202200027
Integral membrane proteins pose considerable challenges to high resolution structural analysis. Maintaining membrane proteins in their native state during protein isolation is essential for structural study of these bio-macromolecules. Detergents are the most commonly used amphiphilic compounds for stabilizing membrane proteins in solution outside a lipid bilayer. We previously introduced a glyco-diosgenin (GDN) detergent that was shown to be highly effective at stabilizing a wide range of membrane proteins. This steroidal detergent has additionally gained attention due to its compatibility with membrane protein structure study via cryo-EM. However, synthetic inconvenience limits widespread use of GDN in membrane protein study. To improve its synthetic accessibility and to further enhance detergent efficacy for protein stabilization, we designed a new class of glyco-steroid-based detergents using three steroid units: cholestanol, cholesterol and diosgenin. These new detergents were efficiently prepared and showed marked efficacy for protein stabilization in evaluation with a few model membrane proteins including two G protein-coupled receptors. Some new agents were not only superior to a gold standard detergent, DDM (n-dodecyl-β-d -maltoside), but were also more effective than the original GDN at preserving protein integrity long term. These agents represent valuable alternatives to GDN, and are likely to facilitate structural determination of challenging membrane proteins. 相似文献
929.
Yangzhi Zhu Rohollah Nasiri Elham Davoodi Shiming Zhang Sourav Saha Matthew Linn Lu Jiang Reihaneh Haghniaz Martin C. Hartel Vadim Jucaud Mehmet R. Dokmeci Anna Herland Ehsan Toyserkani Ali Khademhosseini 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(11):2207017
The contact lens (CL) industry has made great strides in improving CL-wearing experiences. However, a large amount of CL wearers continue to experience ocular dryness, known as contact lens-induced dry eye (CLIDE), stemming from the reduction in tear volume, tear film instability, increased tear osmolarity followed by inflammation and resulting in ocular discomfort and visual disturbances. In this article, to address tear film thinning between the CL and the ocular surface, the concept of using a CL with microchannels to deliver the tears from the pre-lens tear film (PrLTF) to the post-lens ocular surface using in vitro eye-blink motion is investigated. This study reports an eye-blink mimicking system with microfluidic poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogel with integrated microchannels to demonstrate eye-blink assisted flow through microchannels. This in vitro experimental study provides a proof-of-concept result that tear transport from PrLTF to post-lens tear film can be enhanced by an artificial eyelid motion in a pressure range of 0.1–5 kPa (similar to human eyelid pressure) through poly(HEMA) microchannels. Simulation is conducted to support the hypothesis. This work demonstrates the feasibility of developing microfluidic CLs with the potential to help prevent or minimize CLIDE and discomfort by the enhanced transport of pre-lens tears to the post-lens ocular surface. 相似文献
930.
Nadeem Muhammad Ilyas Samina Haq Ehsan Ul Ahmed Furqan Zain-ul-Abdein Muhammad Karim Muhammad Ramzan Abdul Zaidi Syed Farrukh Alam 《SILICON》2022,14(5):2337-2349
Silicon - This research aims to study the behavior of silica based geopolymeric material (22–28%Si) from granitic waste. Granitic waste in powder form was used as main precursor in... 相似文献