Predicting Shear Capacity of RC Beams Strengthened with NSM FRP Using Neural Networks

This research aims to predict the shear capacity of NSM FRP beams using the neural network method. The study investigates the key considerations and the necessary analysis for this prediction. NSM FRP beams are reinforced concrete beams that are strengthened with near-surface mounted (NSM) fiber-reinforced polymer (FRP) composites. Accurately predicting their shear capacity is important for ensuring their safety and reliability in real-world applications. The neural network method is a machine learning approach that is increasingly used in engineering analysis and design. The study explores how this method can be used to predict the shear capacity of NSM FRP beams and what factors should be taken into account in this analysis. The research also discusses the analytical approach required for this prediction, highlighting the necessary steps for obtaining accurate results. Overall, this study provides valuable insights into the use of the neural network method for predicting the shear capacity of NSM FRP beams. The findings can help inform future research and practical applications in the field of structural engineering, contributing to the development of safer and more reliable structures

Multi-period supplier selection under price uncertainty

Cataloged from PDF version of article.We consider a problem faced by a procurement manager who needs to purchase a large volume of multiple items over multiple periods from multiple suppliers that provide base prices and discounts. Discounts are contingent on meeting various conditions on total volume or spend, and some are tied to future realizations of random events that can be mutually verified. We formulate a scenario-based multi-stage stochastic optimization model that allows us to consider random events such as a drop in price because of the most favoured customer clauses, a price change in the spot market or a new discount offer. We propose certainty-equivalent heuristics and evaluate the regret of using them. We use our model for three bidding events of a large manufacturing company. The results show that considering most favored customer clauses in supplier offers may create substantial savings that may surpass the savings from regular discount offers

A Study of Zero-Out Auctions: Testbed Experiments of a Process of Allocating Private Rights to the Use of Public Property

The study examines a proposal to auction rights to land at a major airport and return the auction revenues to the winners. Experiments with such auctions are reported. New econometric models of the process are developed and evaluated

Rigidity of Linearly Constrained Frameworks

We consider the problem of characterising the generic rigidity of bar-joint frameworks in R d in which each vertex is constrained to lie in a given affine subspace. The special case when d = 2 was previously solved by I. Streinu and L. Theran in 2010. We will extend their characterisation to the case when d ≥ 3 and each vertex is constrained to lie in an affine subspace of dimension t, when t = 1, 2 and also when t ≥ 3 and d ≥ t(t−1). We then point out that results on body-bar frameworks obtained by N. Katoh and S. Tanigawa in 2013 can be used to characterise when a graph has a rigid realisation as a d-dimensional body-bar framework with a given set of linear constraints

Highly Transparent, Flexible, and Thermally Stable Superhydrophobic ORMOSIL Aerogel Thin Films

Cataloged from PDF version of article.We report preparation of highly transparent, flexible, and thermally stable superhydrophobic organically modified silica (ORMOSIL) aerogel thin films from colloidal dispersions at ambient conditions. The prepared dispersions are suitable for large area processing with ease of coating and be:ing directly applicable without requiring any pre- or post-treatment on a variety of surfaces including glass, wood, and plastics. ORMOSIL films exhibit and retain superhydrophobic behavior up to 500 degrees C and even on bent flexible substrates. The surface of the films can be converted from superhydrophobic (contact angle of 179.9 degrees) to superhydrophilic (contact angle of <5 degrees) by calcination at high temperatures. The wettability of the coatings can be changed by tuning the calcination temperature and duration. The prepared films also exhibit low refractive index and high porosity making them suitable as multifunctional coatings for many application fields including solar cells, flexible electronics, and lab on papers

Glycosaminoglycan mimetric peptide nanofibers promote mineralization by osteogenic cells

Cataloged from PDF version of article.Bone tissue regeneration is accomplished by concerted regulation of protein-based extracellular matrix components, glycosaminoglycans (GAGs) and inductive growth factors. GAGs constitute a significant portion of the extracellular matrix and have a significant impact on regulating cellular behavior, either directly or through encapsulation and presentation of growth factors to the cells. In this study we utilized a supramolecular peptide nanofiber system that can emulate both the nanofibrous architecture of collagenous extracellular matrix and the major chemical composition found on GAGs. GAGs and collagen mimetic peptide nanofibers were designed and synthesized with sulfonate and carboxylate groups on the peptide scaffold. The GAG mimetic peptide nanofibers interact with bone morphogenetic protein-2 (BMP-2), which is a critical growth factor for osteogenic activity. The GAG mimicking ability of the peptide nanofibers and their interaction with BMP-2 promoted osteogenic activity and mineralization by osteoblastic cells. Alkaline phosphatase activity, Alizarin red staining and energy dispersive X-ray analysis spectroscopy indicated the efficacy of the peptide nanofibers in inducing mineralization. The multifunctional and bioactive microenvironment presented here provides osteoblastic cells with osteogenic stimuli similar to those observed in native bone tissue

Optimization of Process-Control Parameters for the Diameter of Electrospun Hydrophilic Polymeric Composite Nanofibers

A composite nanofiber composed of three polymers, namely polyvinyl alcohol/polyvinyl pyrrolidone/polyethylene oxide, is produced. The experiments are constructed using three design of experiment techniques, Taguchi L9, Taguchi L27, and Screening method. The experiments are verified using the analysis of variance (ANOVA) method and later a mathematical model is developed using the regression method. The impact of electrospun processing parameters, namely applied voltage, flow rate, and working distance, on nanofibers' diameter is measured. The working distance is a significant factor in controlling the size of the fiber diameter, while the applied voltage has the lowest effect on it. As a result of the regression equation, a Genetic algorithm is used to find the optimum variables for the required fiber diameter, which is 156 nm for flow rate = 0.001 mL h−1, voltage = 30 kV, and distance = 200 mm with a 3% difference from the experimental fiber diameter

Template free preparation of nanoporous organically modified silica thin films on flexible substrates

Cataloged from PDF version of article.We report the preparation and characterization of nanoporous organically modified silica (ormosil) thin films at room temperature and neutral pH conditions from homogeneous methyl silsesquioxane (MSQ) gels. Universally applicable and stable colloidal ormosil suspensions are prepared from the gels by sonication and coated to the substrates including glass, paper and plastics. The nanoporosity and thickness of the films can be tuned, which makes them suitable for certain applications including sensing, functional coatings, and low-dielectric materials. We demonstrate the antireflection property of the films on glass, cellulose acetate (CA) and polyetherimide (PEI) substrates. The films on CA and PEI retain their antireflection property after multiple bending cycles. Furthermore, films are intrinsically hydrophobic, over a wide pH range, with static contact angles up to 143° on paper and 123° on glass and CA. Producing nanoporous ormosil thin films on flexible substrates may expand their use in low cost electronic, optical devices and sensors, and lab-on-paper applications

Template-Directed Synthesis of Silica Nanotubes for Explosive Detection

Cataloged from PDF version of article.Fluorescent porous organic-inorganic thin films are of interest of explosive detection because of their vapor phase fluorescence quenching property. In this work, we synthesized fluorescent silica nanotubes using a biomineralization process through self-assembled peptidic nanostructures. We designed and synthesized an amyloid-like peptide self-assembling into nanofibers to be used as a template for silica nanotube formation. The amine groups on the peptide nanofibrous system were used for nucleation of silica nanostructures. Silica nanotubes were used to prepare highly porous surfaces, and they were doped with a fluorescent dye by physical adsorption for explosive sensing. These porous surfaces exhibited fast, sensitive, and highly selective fluorescence quenching against nitro-explosive vapors. The materials developed in this work have vast potential in sensing applications due to enhanced surface area. © 2011 American Chemical Society

Grating coupler integrated photodiodes for plasmon resonance based sensing

Cataloged from PDF version of article.In this work, we demonstrate an integrated sensor combining a grating-coupled plasmon resonance surface with a planar photodiode. Plasmon enhanced transmission is employed as a sensitive refractive index (RI) sensing mechanism. Enhanced transmission of light is monitored via the integrated photodiode by tuning the angle of incidence of a collimated beam near the sharp plasmon resonance condition. Slight changes of the effective refractive index (RI) shift the resonance angle, resulting in a change in the photocurrent. Owing to the planar sensing mechanism, the design permits a high areal density of sensing spots. In the design, absence of holes that facilitate resonant transmission of light, allows an easy-to-implement fabrication procedure and relative insensitivity to fabrication errors. Theoretical and experimental results agree well. An equivalent long-term RI noise of 6.3 x 10(-6) RIU/root Hz is obtained by using an 8 mW He-Ne laser, compared to a shot-noise limited theoretical sensitivity of 5.61 x 10(-9) RIU/root Hz. The device features full benefits of grating-coupled plasmon resonance, such as enhancement of sensitivity for non-zero azimuthal angle of incidence. Further sensitivity enhancement using balanced detection and optimal plasmon coupling conditions are discussed