Development of a void ratio-moisture ratio-net stress framework for the prediction of the volumetric behavior of unsaturated granular materials

Despite extensive research on the behavior of unsaturated fine-grained materials, there is still a lack of understanding of the volumetric behavior of unsaturated granular materials. In this research, a model has been developed to predict the fundamental volumetric behavior of unsaturated granular materials through loading and wetting state paths. In this regard, a loading-wetting surface was developed in a space of void ratio-moisture ratio-net stress. A distinctive feature of the proposed model is the relative simplicity in obtaining the model parameters using conventional geotechnical testing equipment. Two types of recycled granular materials, commonly applied in unbound pavements were used, namely, recycled crushed brick (CB) and excavation waste rock (WR). The uniqueness of the developed surface was evaluated by employing a number of loading and wetting state paths. The results indicate that the developed surface is unique in its loading state paths; however, it only shows uniqueness in its wetting state paths for stress levels greater than 2000 kPa. The proposed model seeks to introduce the application of the unsaturated soil mechanics theory, for predicting the behavior of granular materials in the field, by providing a practical and cost-effective methodology.     

SAPPHIRE: A toolkit for building efficient stream programs for medical video analysis

This paper describes the design and implementation of SAPPHIRE – a novel middleware and software development kit for stream programing on a heterogeneous system of multi-core multi-CPUs with optional hardware accelerators such as graphics processing unit (GPU). A stream program consists of a set of tasks where the same tasks are repeated over multiple iterations of data (e.g., video frames). Examples of such programs are video analysis applications for computer-aided diagnosis and computer-assisted surgeries. Our design goal is to reduce the implementation efforts and ease collaborative software development of stream programs while supporting efficient execution of the programs on the target hardware. To validate the toolkit, we implemented EM-Automated-RT software with the toolkit and reported our experience. EM-Automated-RT performs real-time video analysis for quality of a colonoscopy procedure and provides visual feedback to assist the endoscopist to achieve optimal inspection of the colon during the procedure. The software has been deployed in a hospital setting to conduct a clinical trial.     

Laboratory measurement of hydraulic conductivity functions of two unsaturated sandy soils during drying and wetting processes

The importance of applying unsaturated soil mechanics to geotechnical engineering design has been well understood. However, the consumption of time and the necessity for a specific laboratory testing apparatus when measuring unsaturated soil properties have limited the application of unsaturated soil mechanics theories in practice. Although methods for predicting unsaturated soil properties have been developed, the verification of these methods for a wide range of soil types is required in order to increase the confidence of practicing engineers in using these methods. In this study, a new permeameter was developed to measure the hydraulic conductivity of unsaturated soils using the steady-state method and directly measured suction (negative pore-water pressure) values. The apparatus is instrumented with two tensiometers for the direct measurement of suction during the tests. The apparatus can be used to obtain the hydraulic conductivity function of sandy soil over a low suction range (0–10 kPa). Firstly, the repeatability of the unsaturated hydraulic conductivity measurement, using the new permeameter, was verified by conducting tests on two identical sandy soil specimens and obtaining similar results. The hydraulic conductivity functions of the two sandy soils were then measured during the drying and wetting processes of the soils. A significant hysteresis was observed when the hydraulic conductivity was plotted against the suction. However, the hysteresis effects were not apparent when the conductivity was plotted against the volumetric water content. Furthermore, the measured unsaturated hydraulic conductivity functions were compared with predictions using three different predictive methods that are widely incorporated into numerical software. The results suggest that these predictive methods are capable of capturing the measured behavior with reasonable agreement.     

Light and Shape-Memory Polymers: Characterization,Preparation, Stimulation,and Application

Shape-memory polymers (SMPs) are smart materials that change shape when exposed to stimuli and have various applications in different fields due to their unique properties. Light, as a kind of electromagnetic radiation, plays an important role in understanding the structure-property relations of SMPs, preparing original shapes, using them as non-contact stimuli sources, and tuning the optical properties of SMPs. This review provides a comprehensive review of the involvement of light in structure-preparation-stimuli-application of SMPs. The review is divided into four sections. First, applications of optical/spectroscopic approaches that provide information for understanding structure-property relations in SMPs, especially during programming and recovery. Second, describes how to build SMPs with light, including different photochemical reactions and 3D photocuring technologies. Third, discusses how light is used to trigger the shape change of SMPs through both photochemical and photothermal mechanisms. Last, focuses on how to take advantage of the shape-memory effect to tune the optical characteristics of polymers, including various structures of SMP color-changing materials and their synthetic strategies. Future research could focus on developing efficient photothermal fillers, new 3D printing techniques for SMPs, exploring their use in biomedical and wearable devices, and optimizing SMPs for industrial applications.     

The development of a fatigue loading spectrum for small wind turbine blades

This paper details a formulation to create a fatigue loading procedure for the blade of a small wind turbine using a combination of detailed short-term aeroelastic and wind measurements and averaged long-term wind data from the Australian Bureau of Meteorology. Detailed aeroelastic measurements from the blade of an operating small wind turbine were acquired simultaneously with wind speed measurements and show that the blade does not respond instantaneously to all changes in wind speed. A methodology has been developed to create a fatigue loading procedure using the blade stress cycles determined from the detailed measurements in conjunction with long-term wind data. The proposed method overcomes the necessity to acquire long-term detailed operational data before developing a blade fatigue loading procedure without compromising on accuracy.     

Environmental Geochemistry of Leachate From Leached Brown Coal Ash

The long-term disposal of ash from brown coal combustion requires a thorough understanding of the geochemical controls on leachate quality. The geochemistry of leachate in ash generated from the combustion of coal in the Latrobe Valley region of Victoria, Australia, has been studied in the field and laboratory. The field studies, conducted over 14 months, showed active leaching and changes in leachate chemistry in the ash with mobilization of some trace elements. A further series of laboratory columns demonstrated similar leaching dynamics. Geochemical modeling indicated that both sulfate and carbonate minerals are the most likely solubility-controlling mineral phases in the ash. For regularly detected trace elements, such as As, Ba, and B but particularly Mo, Se, and Sr, the trends suggest that adsorption and coprecipitation controls are also important. The overall approach adopted in this paper has enabled a more realistic assessment of the controlling processes for solute transport during the active leaching phase of ash disposal, thereby improving long-term environmental management.     

An experimental investigation of the properties of cross-ply laminate used for manufacturing of small aircraft components

This paper discusses the observations and results from an experimental investigation of cross ply laminates used to construct major structural components of a small aircraft manufactured in Australia. The static and fatigue experimental results are compared with established models in composites analysis and with the available data in composite databases. An analysis was done to statistically quantify any deviation of actual properties from the calculated values and investigate the differences in designed and actual capacities/operational life of the components made using this laminates.     

Theoretical p-y Curves for Laterally Loaded Single Piles in Undrained Clay Using Bezier Curves

An alternative method was introduced for predicting the nonlinear p-y curves for monotonic unidirectional laterally loaded single piles in uniform undrained clay. On the basis of numerical studies, closed-form solutions were developed for locating the start of yield (ye); the ultimate yield point (yu); and the initial stiffness, Ki of the p-y curve. The nonlinear section of the curve between the start of the yield and the ultimate yield point was represented by Bezier polynomials (also known as de Casteljau’s algorithm). Using these relationships, a direct method of constructing the p-y curves was presented considering either tension failure or no tension failure of soils. For a typical pile configuration, the resulting load-deflection response was observed to compare favorably with the predictions from FLAC analysis and Matlock.     

Loose abrasive blasting as an alternative to slurry polishing of optical fibre end faces

A novel method of polishing the end face of an optical fibre by blasting it with loose dry abrasive grit travelling at high speeds is presented. The method, called loose abrasive blasting (LAB), is specifically designed to improve the surface quality of micro-lenses ground at the tips of optical fibres. Thus, the method described is suitable for polishing non-flat surfaces. Blasting is carried out by immersing the fibre tip in a stream of high kinetic energy abrasive grit. The surface finish attainable using LAB is compared with that of cleaved, ground and slurry polished fibre end faces. Optical microscopy photographs are presented as a qualitative comparison. The surface roughnesses are measured using atomic force microscopy (AFM). For cleaved fibres, the surface roughness improved by a factor of 2 and 6 for slurry polished and dry diamond blasted fibres, respectively.