Sharif Digital Repository

Many companies face challenges in reducing their supply chain costs while increasing sustainability and customer service levels. A comprehensive framework for a sustainable closed-loop supply chain (CLSC) network is a practical solution to these challenges. Hence, for the first time, this study considers an integrated multi-objective mixed-integer linear programming (MOMILP) model to design sustainable CLSC networks with cross-docking, location-inventory-routing, time window, supplier selection, order allocation, transportation modes with simultaneous pickup, and delivery under uncertainty. An intelligent simulation algorithm is proposed to produce CLSC network data with probabilistic... 

Since the advent of blockchain technology (BT), extensive research has explored using this technology in non-financial cases. The healthcare industry is one of the non-financial sectors that BT has significantly impacted. In this paper, for the first time, barriers to implement BT-based platforms from a balanced scorecard perspective in the healthcare sector are introduced, and these barriers are prioritized using a structural approach based on the weighted influence non-linear gauge system. Unlike other structural models such as decision-making trial and evaluation laboratory (DEMATEL), in this approach, both strength and influence intensity of components are considered in the ranking... 

The disasters caused by epidemic outbreaks is different from other disasters due to two specific features: their long-term disruption and their increasing propagation. Not controlling such disasters brings about severe disruptions in the supply chains and communities and, thereby, irreparable losses will come into play. Coronavirus disease 2019 (COVID-19) is one of these disasters that has caused severe disruptions across the world and in many supply chains, particularly in the healthcare supply chain. Therefore, this paper, for the first time, develops a practical decision support system based on physicians' knowledge and fuzzy inference system (FIS) in order to help with the demand... 

Municipal solid waste (MSW) directly impacts community health and environmental degradation; therefore, the management of MSW is crucial. Medical waste is a specific type of MSW which is generally divided into two categories: infectious and non-infectious. Wastes generated by coronavirus disease 2019 (COVID-19) are classified among infectious medical wastes; moreover, these wastes are hazardous because they threaten the environment and living organisms if they are not appropriately managed. This paper develops a bi-objective mixed-integer linear programming model for medical waste management during the COVID-19 outbreak. The proposed model minimizes the total costs and risks, simultaneously,... 

In the real world, there are complex decision-making problems in which a variety of intertwined factors and hierarchical structures exist, and it is difficult or impossible to solve these problems using classical methods. The prioritization of circular economy (CE) adoption barriers is one such complex problem that cannot be solved using current classical methods. Hence, in this paper, for the first time, a new method, namely, FBWDS, is developed. FBWDS derives from the combination of fuzzy best–worst method (BWM), fuzzy decision-making trial and evaluation laboratory (DEMATEL), and Supermatrix structure. This proposed method establishes weights of the intertwined factors in hierarchical... 

Since the advent of blockchain technology (BT), extensive research has explored using this technology in non-financial cases. The healthcare industry is one of the non-financial sectors that BT has significantly impacted. In this paper, for the first time, barriers to implement BT-based platforms from a balanced scorecard perspective in the healthcare sector are introduced, and these barriers are prioritized using a structural approach based on the weighted influence non-linear gauge system. Unlike other structural models such as decision-making trial and evaluation laboratory (DEMATEL), in this approach, both strength and influence intensity of components are considered in the ranking... 

Al-Zn-Mg-Cu alloys (7xxx series Al alloys) are extensively used for their superior mechanical and corrosion performance. These properties are microstructure-sensitive and highly dependent on the formation, growth and coarsening of precipitates. To date, a wide variety of ageing procedures have been developed to tailor the evolved microstructures so as to yield a good combination of mechanical capacity and corrosion resistance of 7xxx series Al alloys. Among these methods, isothermal ageing, multi-stage ageing, non-isothermal ageing, retrogression and re-ageing (RRA), and stress ageing (i.e. creep ageing) are the most significant. In the present review, all of these approaches are... 

After an earthquake, the residual stiffness and strength of structural elements are typically estimated based on a qualitative visual inspection of cracks that is prone to error. In this paper a new approach is proposed to automatically estimate the updated stiffness and strength of damaged unreinforced masonry walls by characterization of crack patterns by a mathematical index. It is shown that structural and textural fractal dimensions of a crack pattern reflect the extent of cracking and the type of cracking or crushing, i.e., whether the cracks pass through joints or whether bricks have been damaged and crushed. Using results of six quasi-static cyclic tests on unreinforced brick masonry... 

In order to optimize the aging treatment of Mg-1.8Zn-0.7Si-0.4Ca alloy, different times and temperatures of solid solution and age hardening were applied to the alloy specimens. Microstructures and mechanical properties of the specimens were investigated using the optical microscopy, field emission scanning electron microscopy equipped with an energy dispersive x-ray spectrometer, x-ray diffraction, hardness, and shear punch tests. The lowest hardness and strength were achieved by solution treating of the alloy at 500 °C for 8 h, presenting the optimal condition for solution treatment of the alloy. The microstructural examinations revealed three different precipitates consisting of CaMgSi,... 

The concept of a nonlinear transfer function of a fibre-optic communication link is reviewed. Also an approximation of the nonlinear transfer function is introduced, which allows to define an equivalent single-span model of a dispersion-managed multi-span system. In this paper we will show its limits of validity and try to extent these limits by enhancing the theoretical model. In this respect we will discuss the impact of dispersion precompensation and show the influence of residual dispersion per span, number of spans and local dispersion on transmission systems with on-off keying and differential phase-shift keying modulation formats. This approach allows fast assessment of the... 

Hydrogen technology through water electrolyzer systems has attracted a great attention to overcome the energy crisis. So, rationally designed non-noble metal based-electrocatalysts with high activity and durability can lead to high performance water electrolyzer systems and high purity hydrogen generation. Herein, a facile two-step method: hydrothermal and electrodeposition, respectively, are developed to decorate highly porous three-dimensional binder-free structure NiFeO/NiO nanosheets array on Ni foam (NiFeO/NiO/NF) with robust adhesion as a high-performance electrode for Hydrogen Evolution Reaction (HER). The electrodeposition process applied after the initial hydrothermal process... 

New techniques for Class-AB Operational Transconductance Amplifiers (OTAs) are presented. These new techniques are two topologies based on current boosting in class-AB stage which achieve considerable improvement of Slew Rate and Gain-Bandwidth while maintaining the same power consumption as the conventional design. Circuit level analysis and simulation results of proposed circuits in 0.18μm CMOS technology for gain, GBW, slew rate, and settling time are presented to prove the effectiveness of the proposed design method  

In this paper, first we shall define a list of technology transfer barriers in the biotechnology field through interviews and literature reviews. Next, we shall categorize them into four major categories of technology, and at last introduce all of the hypotheses on the existence of relationship between each part of technology and failure in the technology transfer process. Questionnaires consisting of two parts were created and handed out to all of the specialists and biotechnology idea-holders in the Iranian National Research center of Biotechnology, Lidco Co, Iran Pastor Institute, Biotechnology Department of University of Tehran, etc. Going on, we've evaluated the factors' validity... 

Most researches on the application of the adjoint method in turbine blade design are concentrated on the aerodynamic shape optimization without considering the heat transfer to/from the blade material. In this study, the adjoint method is extended to the conjugate heat transfer problems in which the viscous flow field is coupled to heat transfer in the solid region. Introducing a new adjoint variable in the solid domain, a heat adjoint equation is derived which is coupled with the energy adjoint equation in the fluid zone at the fluid/solid interface. The detailed mathematical description associated with the derivation of the heat adjoint equation with corresponding boundary conditions are... 

This article presents a novel identification approach which can deal with nonlinear and time-varying characteristics of complex dynamic systems, especially an aerial vehicle in the entire flight envelope. A set of local sub-models are first developed at different operating points of the system, and subsequently a self-organizing multi-model ensemble is introduced to aggregate the outputs of the local models as a single model. The number of employed local models in the proposed multi-model ensemble is optimized using a novel self-organizing approach. Also, wavelet neural networks, which combine both the universal approximation property of neural networks and the wavelet decomposition... 

L-tryptophan functionalized AgNPs were successfully fabricated using a one-pot synthesis method and assessed as a colorimetric probe for rapid and accurate determination of Mg2+ ions. The developed sensor showed a selective response towards Mg2+ with no interference from Ca2+ in the wide concentration range of 1–200 µM. The sensor's response was optimized in the pH range of 9–10, which can be attributed to the protonation of amine groups and their interaction with Mg2+ ions. The stability and selectivity of the sensor were examined in different salt (NaCl) and other metal ions, respectively. The L-tryptophan-AgNPs sensor detected Mg2+ with the limit of detection of 3 µM, which is way lower... 

In this paper, we propose what we believe is a novel sensitive micro-optoelectromechanical systems (MOEMS) accelerometer based on intensity modulation by using a one-dimensional photonic crystal. The optical sensing system of the proposed structure includes an air-dielectric multilayer photonic bandgap material, a laser diode (LD) light source, a typical photodiode (1550 nm) and a set of integrated optical waveguides. The proposed sensor provides several advantages, such as a relatively wide measurement range, good linearity in the whole measurement range, integration capability, negligible cross-axis sensitivity, high reliability, and low air-damping coefficient, which results in a wider... 

In the present work, the effect of brazing pa rameters on the properties of the brazed joint of pure titanium and 304 stainless steel (304SS) was investigated. Three different Ag-Cu filler metals were used, while the temperature and time of brazing were in the range of 800-950°C and 5-45 minutes, respectively. The microstructural observations show that, depending on the brazing conditions, different intermetallic phases such as CuTi2, CuTi, Cu3Ti4, and FeTi were formed at the phases interface. Based on the microstructural observations, a model was developed to characterize the formation of phases at the interfaces and brazed joint. The results show that, while some phases may form during the... 

Empirical drift capacity models for in-plane loaded unreinforced masonry (URM) walls are derived from results of quasi-static cyclic shear-compression tests. The experimentally determined drift capacities are, however, dependent on the applied demand, i.e., on the loading protocol that is used in the test. These loading protocols differ between test campaigns. The loading protocols applied in tests are also different from the displacement histories to which URM walls are subjected in real earthquakes. In the absence of experimental studies on the effect of loading histories on the wall response, this article presents numerical simulations of modern unreinforced clay block masonry walls that... 

Displacement-based assessment procedures require as input reliable estimates of the deformation capacity of all structural elements. For unreinforced masonry (URM) walls, current design codes specify the in-plane deformation capacity as empirical equations of interstory drift. National codes differ with regard to the parameters that are considered in these empirical drift capacity equations, but the inhomogeneity of datasets on URM wall tests renders it difficult to validate the hypotheses with the currently available experimental data. This paper contributes to the future development of such empirical relationships by investigating the sensitivity of the drift capacity to the shear span,...