Sharif Digital Repository

Characterizing and modeling the fatigue performance of an asphalt binder is important when designing asphalt mixtures which can resist premature fatigue failure. Performance grading (PG) standards include the fatigue factor (G*.sinδ) to evaluate the fatigue resistance of asphalt binders. This criterion seems to be inaccurate, especially when applied to modified asphalt binders. American Association of State Highway and Transportation Officials (AASHTO) TP 101 has been designed to evaluate the fatigue resistance of asphalt binders using Schapery’s work potential theory. The damage evolution rate (α parameter) is the key element of this method and is calculated from the rheological properties... 

The main goal of this study is to investigate the effects of plaque structure on its stress distribution. Rupture of plaque causes cerebrovascular diseases which lead to high mortality rates all over the world. Computers are powerful tools to understand the mechanism of plaque rupture. In this study, 3D fluid structure interaction simulation is constructed in ABAQUS 6.13 to clarify the relation between stress distribution of plaque and its structure. A model of common carotid artery with distributed stenosis was chosen for the simulation. To investigate the effects of plaque structure on stress distribution, thickness of fibrous cap and lipid core size were varied in the stenosis.... 

Incorporation of reclaimed asphalt pavement (RAP) and crumb rubber (CR) materials into asphalt mixtures have been of great importance from sustainability point of view. Although, inclusion of RAP materials in asphalt mixtures improves the rutting resistance at high temperature, the low temperature (LT) and intermediate temperature (IT) cracking performance of RAP mixtures may need additional considerations. In this regard, different schemes of modification have been applied to RAP mixtures to address its performance weaknesses. This study evaluated the effect of RAP and CR in combination with Sasobit and hydrated lime on the cracking performance of asphalt mixtures. The LT and IT... 

Worldwide energy and environmental issues are forcing researchers to develop a green approach to produce a clean energy. However, traditional methods in reforming of fossil fuels to produce hydrogen (H2) are causing CO2 emission. Hydrogen is therefore an indirect greenhouse gas with a global warming potential. Hydrogen with high specific energy density can be considered as an efficient energy carrier as compared to fossil fuels. But hydrogen production from water splitting reaction has low efficiency, which limits its generation by green approach. For addressing this issue, different chemical hole scavengers have been applied, which is causing further environmental and economic problems. By... 

Magnetically separable inorganic-organic hybrid material H 5PW10V2O40/pyridino-Fe 3O4 (HPA/TPI-Fe3O4) nanoparticles provide an efficient and economic route for the synthesis of substituted bis(indolyl)methanes by the electrophilic substitution of indole with various aldehydes and ketones under solvent-free conditions with excellent yields in <30 min. This catalyst was prepared by the chemically anchoring H 5PW10V2O40 onto Fe3O 4 nanoparticles via the use of N-[3-(triethoxysilyl)propyl] isonicotinamide (TPI) linker. High catalytic activity and ease of recovery using an external magnetic field are additional eco-friendly attributes of this new catalytic system. The catalyst was recycled at... 

Background/Purpose: To prevent falling, a common incident with debilitating health consequences among stroke survivors, it is important to identify significant fall risk factors (FRFs) towards developing and implementing predictive and preventive strategies and guidelines. This review provides a systematic approach for identifying the relevant FRFs and shedding light on future directions of research. Methods: A systematic search was conducted in 5 popular research databases. Studies investigating the FRFs in the stroke community were evaluated to identify the commonality and trend of FRFs in the relevant literature. Results: twenty-seven relevant articles were reviewed and analyzed spanning... 

In the bone tissue engineering field (BTE), it is of significant importance to develop bioactive multifunctional scaffolds with enhanced osteoconductivity, osteoinductivity, and antibacterial properties required for lost bone tissue regeneration. In this work, a bioactive glass-ceramic scaffold was manufactured via a novel polymer-derived ceramics (PDC) manufacturing method. To gain antibacterial properties, the silver ions were incorporated in controlled amount along with other precursors in the PDC processing stage. Microstructural and structural properties of the fabricated silicate-phosphate glass-ceramic scaffold were evaluated by scanning electron microscopy (SEM) equipped with energy... 

In the bone tissue engineering field (BTE), it is of significant importance to develop bioactive multifunctional scaffolds with enhanced osteoconductivity, osteoinductivity, and antibacterial properties required for lost bone tissue regeneration. In this work, a bioactive glass-ceramic scaffold was manufactured via a novel polymer-derived ceramics (PDC) manufacturing method. To gain antibacterial properties, the silver ions were incorporated in controlled amount along with other precursors in the PDC processing stage. Microstructural and structural properties of the fabricated silicate-phosphate glass-ceramic scaffold were evaluated by scanning electron microscopy (SEM) equipped with energy... 

Nonspecific low back pain (NSLBP) constitutes a critical health challenge that impacts millions of people worldwide with devastating health and socioeconomic consequences. In today’s clinical settings, practitioners continue to follow conventional guidelines to categorize NSLBP patients based on subjective approaches, such as the STarT Back Screening Tool (SBST). This study aimed to develop a sensor-based machine learning model to classify NSLBP patients into different subgroups according to quantitative kinematic data, i.e., trunk motion and balance-related measures, in conjunction with STarT output. Specifically, inertial measurement units (IMU) were attached to the trunks of ninety-four... 

Let R be a ring and f(x1,..., xn) be a polynomial in noncommutative indeterminates x1,..., xn with coefficients from ℤ and zero constant. The ring R is said to be an f-ring if f(r1,..., rn) = 0 for all r1,..., rn of R and a virtually f-ring if for every n infinite subsets X1,..., Xn (not necessarily distinct) of R, there exist n elements r1 ∈ X1,...,rn ∈ Xn such that f(r1,..., rn) = 0. Let R* be the 'smallest' ring (in some sense) with identity containing R such that Char (R) = Char (R*). Then denote by ZR the subring generated by the identity of R* and denote by f̄R the image of f in ZR [x1,..., xn] (the ring of polynomials with coefficients in ZR in commutative indeterminates x1,..., xn).... 

To exert the optimum effect, the chemical exchange process to boron isotope separation was investigated. In this enrichment method the distillation of dimethyl ether-boron trifluoride complex, which was one of the most efficient industrial methods for purification of isotope boron-10, was optimized. In chemical exchange process of boron isotopes separation two chemical reactions occur. The first one is the decomposition reaction that is an endothermic reaction. The second one is the exchange reaction that is a pyrogenic reaction. With increasing temperature, the decomposition reaction is speeded while the exchange reaction is slowed down. Affecting on both decomposition and exchange... 

We have recently introduced a high-level extension for stochastic activity networks (SANs) called coloured stochastic activity networks (CSANs). CSANs have several distinguishing properties, which make them quite appropriate for modeling and evaluation of software performance and dependability. CSANs have introduced a construct called coloured place for data manipulation. A coloured place holds a list of tokens of a userdefined token type. CSAN models can be evaluated by state space analysis techniques or discrete-event simulation. However, their state spaces will become very large, even for a small CSAN model. For efficient evaluation of these models by state space analysis methods, we will...