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Showing 5 results for Noei
Preparation and Improvement of Shear Strength of a Water-Redispersible Waterborne Acrylic Adhesive for Making Cellulose Joints

Volume 3, Issue 1 (Spring 98 2019)
Abstract
Research subject: In recent years, many attempts have been devoted to industrial usage of bio-based adhesives, as a result of fossil resources shortage and unusual increase in oil-based products prices. Adhesion strength of this category of adhesives, however, needs improvement.
Research approach: In the current study, lap-shear strength of joints made of a natural polymer, Persian gum (PG), exuded from wild almond tree, and three various substrates, glass, poly(ethylene terephthalate), and cellulose fabric, was investigated. Furthermore, in order to prepare powder acrylic adhesive and evaluate its adhesion to aforementioned substrates, the gum dispersion was blended with synthesized poly(methyl methacrylate-co-butyl acrylate) random copolymer containing 30 wt.% methyl methacrylate (MBC30). Molecular interactions in PG, MBC30, and 50 wt. % PG-containing blend were characterized by Fourier transform infrared spectroscopy. Moreover, morphology of blends containing various amounts of PG was evaluated using scanning electron microscopy of their fractured cross sections.
Main results: The textile joint made with PG dispersion in water showed high shear strength of about 340 kPa. However, PG could not form a suitable joint with glass and polyester substrates, as a consequence of its inability to form a homogeneous film, excessive brittleness, and its inability to diffuse and mechanically interlock with the substrates. Results showed that using an adhesive system containing 50/50 PG/MBC30, besides enabling preparation of powder adhesive, shear strength increased to 20, 11, and 14-fold with respect to pristine MBC30 on glass, poly(ethylene terephthalate), and textile substrates, respectively. In other words, shear strength of an adhesive could be improved by promoting the adhesive constituents interactions and subsequent increase in the blend cohesiveness, on the one hand, and increment of its adhesion to substrate, on the other hand. In the current research, Persian gum was introduced as a water-redispersing agent for acrylic pressure-sensitive adhesives and new adhesive systems were invented with usability in cellulose industry.

Three new records of Collembola (Hexapoda) from Birjand (South Khorasan, Iran)

Volume 9, Issue 3 (9-2023)
Abstract

During samplings were performed during 2019 in Birjand area located in South Khorasan province, three species are identified from families Entomobryidae and Bourletiellidae. Drepanura tuxeni Nosek, 1964, Drepanosira gisini Nosek, 1964 and Cassagnaudiella c.f. gamae (Bretfeld, 1994) are newly reported for the Iranian fauna of Collembola. The material examined, brief description and some illustration were given. Cassagnaudiella c.f. gamae represents the second species record of the family Bourletiellidae from Iran.


Optimal Fractional order iterative learning control for single-link robot control

Volume 15, Issue 10 (1-2016)
Abstract
In this paper, a new type of iterative learning control systems with fractional order known as iterative learning control with fractional order derivative and iterative learning control with fractional proportional–derivative for linearized systems of single-link robot arm is introduced. First order derivative of classic Arimoto is used for tracking error in updating law of derivative iterative learning control. Suggested method in this paper implement tracking error for updating control law of iterative learning of fractional order. For the first time, nonlinear robot system is linearized by input feedback linearization. Then, convergence analysis of iterative learning control law of type PD^alpha is studied.In the next step, we define a criteria for parameters optimization of proposed controller by using Biogeography-based optimization algorithm. Both updating law of fractional order iterative learning control (D^alpha-type ILC and PD^alpha-type ILC) is applied on linearized robot arm and performance of both controller for different value of alpha is presented. For improving the performance of closed loop system, coefficient of fractional order iterative learning control (proportional and derivative coefficients) is optimized by BBO algorithm. Proposed iterative learning control is compared with common type of system.
Topology Optimization of Structure in the Fluid-Structure Interaction Problem using the Level Set Method

Volume 24, Issue 8 (August 2024)
Abstract
 This research focuses on topology optimization of fluid-structure interaction (FSI) problems using the level set method. To couple the fluid and structure equations, the Arbitrary Lagrangian-Eulerian (ALE) description is employed within a monolithic formulation. The use of ALE in FSI problems, while eliminating numerical instabilities caused by the convective term, enhances the speed and accuracy of finite element solutions in fluid-structure interaction. Additionally, considering the fluid in the unsteady state allows for the interpretation of optimal topology at any given moment of the analysis. The objective function of the optimal topology design problem is to minimize the structural compliance in the dry state, subject to a fixed volume of the design domain. To determine the normal velocity in the reaction-diffusion equation (RDE), adjoint sensitivity analysis based on pointwise gradients is used. The results obtained from this approach, compared to other topology optimization methods in the literature, demonstrate higher accuracy and clearer definition of structural boundaries.
Investigating the possible roles of mutations in axin1 and axin2 genes in colorectal cancer

Volume 28, Issue 2 (Spring 2025)
Abstract
Introduction: Colorectal cancer (CRC) is one of the leading cancers, following skin, breast, and stomach cancers. This study aimed to investigate the relationship between mutations in axin1 and axin2 in association with CRC.
Methods: Our study contains 147 fresh frozen samples from CRC patients, 25 normal samples, and 3 cell lines, including HT29, SW480, and CACO-2. The chosen SNPs from databases are placed in exon 5 of axin1, in exon 2 of axin1, and in exon 7 of axin2. By PCR-RFLP method, mutated samples were identified and sequenced.
Results: The results showed that mutations in the single-nucleotide polymorphism (SNP) in axin2 were observed in 1 out of 147 patient samples (0.68%). In the three sequences examined in axin2 (exon 7), mutations in SNP with rs79024445 at A2052C were observed. Statistical analysis of clinical and pathological data of patients showed a significant relationship between the tumor size factor and grade of cancer (P=0.016) as well as the degree of tumor diffusion to the lymph nodes factor with a grade of cancer (P=0.001).
Conclusion: The multi-factorial nature of cancer, the high genetic diversity of the Iranian population, and the limited statistical population could affect these outcomes. The observed mutations in each sample can also indicate the importance of personalized medicine in studying diseases
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