Multi-Scale Analysis for Assessing the Impact of Material Composition and Weave on the Ultimate Strength of GFRP Stiffened Panels

A micro-meso-macro analysis framework based on the multi-scale method was employed to analyse the mechanical behaviour of marine GFRP stiffened panels. The study aims to establish a procedure for assessing the impact of material composition and weave on the ultimate strength of GFRP stiffened panels. The ultimate strength assessment was an essential step in the design process, and the investigation of construction materials has a great benefit to the lightweight design of marine composite structures. The micro- and meso-scale RVE models of components used in GFRP materials are established, and their failure criteria and stiffness degradation models are created using the user-defined material subroutine VUMAT in ABAQUS. The equivalent material properties at the micro-scale (meso-scale) obtained by a homogenisation method are used to define the meso-scale (macro-scale) mechanical properties in the finite element analyses. The multi-scale method assesses the macro-mechanics of composites, and it is shown that the ultimate strength of GFRP stiffened panels is mainly determined by the failure of CSM fibre bundles and WR yarns. Parametric study of the meso-mechanics of composite materials can provide an analysis tool to obtain the optimal macro ultimate strength of the composite stiffened panel

Optimization of Scanning and Counting Sensor Layout for Full Route Observability with a Bi-Level Programming Model

Utilizing the data obtained from both scanning and counting sensors is critical for efficiently managing traffic flow on roadways. Past studies mainly focused on the optimal layout of one type of sensor, and how to optimize the arrangement of more than one type of sensor has not been fully researched. This paper develops a methodology that optimizes the deployment of different types of sensors to solve the well-recognized network sensors location problem (NSLP). To answer the questions of how many, where and what types of sensors should be deployed on each particular link of the network, a novel bi-level programming model for full route observability is presented to strategically locate scanning and counting sensors in a network. The methodology works in two steps. First, a mathematical program is formulated to determine the minimum number of scanning sensors. To solve this program, a new ‘differentiating matrix’ is introduced and the corresponding greedy algorithm of ‘differentiating first’ is put forward. In the second step, a scanning map and an incidence matrix are incorporated into the program, which extends the theoretical model for multiple sensors’ deployment and provides the replacement method to reduce total cost of sensors without loss of observability. The algorithm developed at the second step involved in two coefficient matrixes from scanning map and incidence parameter enumerate all possibilities of replacement schemes so that cost of different combination schemes can be compared. Finally, the proposed approach is demonstrated by comparison of Nguyen-Dupuis network and real network, which indicates the proposed method is capable to evaluate the trade-off between cost and all routes observability

Calibration and development of safety performance functions for two-way stop-control intersections on rural two-lane highways in Louisiana

The first edition of the Highway Safety Manual (HSM) contains a simplistic version of the crash prediction model for two-way stop-controlled intersections (TWSC) on rural two-lane highways. This model considers AADT on major and minor roads, with the base conditions defined as no intersection skewness, no turning lanes, and no lighting. A crash modification factor (CMF) will be applied if an intersection has conditions different from the base condition. However, the HSM model does not take account of curvature. It is well known that curved TWSC intersections are less safe than non-curved ones, particularly on rural two-lane roadways. This paper presents the development of crash prediction models incorporating intersection geometrics for TWSC intersections on rural two-lane highways in Louisiana. Then, it compares the results from the developed model with the calibrated HSM model. The negative binomial model was used with 5126 TWSC intersections verified one by one, including both three- and four-leg intersections from all parishes (counties). The estimation results indicate that AADT, curve radius, and intersection skewness angle significantly impact expected crash frequency for both three- and four-leg intersections. This research utilizes cumulative residual plots, mean absolute error, and root mean square error for comparative analysis of HSM models, HSM models with calibration, and Louisiana-specific models. The results show that Louisiana-specific SPFs outperformed the calibrated SPFs with superior reliability. Calibration factors of 0.58 for three-leg intersections and 0.46 for four-leg intersections are estimated, suggesting that the original HSM model overpredicts crashes in Louisiana

Thermally Induced Increase in Energy Transport Capacity of Silkworm Silks

ABSTRACT: This work reports on the first study of thermally induced effect on energy transport in single filaments of silkworm (Bombyx mori) fibroin degummed mild (type 1), moderate (type 2), to strong (type 3). After heat treatment from 140 to 220 C, the thermal diffusivity of silk fibroin type 1, 2, and 3 increases up to 37.9, 20.9, and 21.5%, respectively. Our detailed scanning electron microscopy study confirms that the sample diameter change is almost negligible before and after heat treatment. Raman analysis is performed on the original and heat

Bone-targeting drug delivery system of biomineral-binding liposomes loaded with icariin enhances the treatment for osteoporosis

Abstract Background Osteoporosis is a bone-incapacitating malady and it is characterized by obvious bone mass loss and bone microarchitecture deterioration. Current treatments for osteoporosis have many limitations, including the non-obvious therapeutic effect and long-term safety issues. Icariin is a pharmacologically active flavonoid glycoside, which shows potential application in treatment of osteoporosis. But its clinical application is limited by the inherent disadvantages such as poor water solubility, first pass effect after oral administration, and low bioavailability. Moreover, due to lack of targeting ability, icariin cannot accumulate at the local diseased region to provide early protection from fractures. To solve the application problems of icariin and enhance its therapeutic effects on osteoporosis, this work aimed to design a targeting drug delivery system of biomineral-binding liposomes (BBL) mediated by pyrophosphate ions. Results Biomineral-binding liposomes enhanced the binding ability of liposomes with hydroxyapatite particles. It increased the serum level of alkaline phosphatase and reduced that of tartrate-resistant acid phosphatase 5b. Meanwhile, BBL increased the mechanical strength of femoral midshaft, preserving the trabecular bone microarchitecture. Moreover, BBL could initiate bone turnover/remodeling of rats with osteoporosis. Conclusions This drug targeting delivery system of BBL loading with icariin showed more therapeutic advantages than the free icariin for the treatment of osteoporosis, which may be a kind of valid candidate in future osteoporosis therapy