Using the NILOA Transparency Framework: It\u27s All About the Process

When the St. John Fisher College Educational Assessment Leadership Team set out to make assessment information readily accessible, they looked to the NILOA Transparency Framework to serve as a guiding template. Recognizing its use nationally to clearly communicate the six assessment components with hexagons, they saw the NILOA model as the ideal format for the design of the institutional assessment website. Assessment results could be organized with the comprehensive, straightforward NILOA graphic. What they did not expect, however, was that the process of adopting the framework would transform not just how assessment “looked”, but how they saw it as well

Heterogeneity of the cancer cell line metabolic landscape

The unravelling of the complexity of cellular metabolism is in its infancy. Cancer-associated genetic alterations may result in changes to cellular metabolism that aid in understanding phenotypic changes, reveal detectable metabolic signatures, or elucidate vulnerabilities to particular drugs. To understand cancer-associated metabolic transformation, we performed untargeted metabolite analysis of 173 different cancer cell lines from 11 different tissues under constant conditions for 1,099 different species using mass spectrometry (MS). We correlate known cancer-associated mutations and gene expression programs with metabolic signatures, generating novel associations of known metabolic pathways with known cancer drivers. We show that metabolic activity correlates with drug sensitivity and use metabolic activity to predict drug response and synergy. Finally, we study the metabolic heterogeneity of cancer mutations across tissues, and find that genes exhibit a range of context specific, and more general metabolic control

Modelling cyclic moisture uptake in an epoxy adhesive

This paper presents a methodology for predicting moisture concentration in an epoxy adhesive under cyclic moisture absorption-desorption conditions. The diffusion characteristics of the adhesive were determined by gravimetric experiments under cyclic moisture conditions and the dependence of diffusion coefficient and saturated mass uptake on moisture history was determined. Non-Fickian moisture absorption was observed during absorption cycles while moisture desorption remained Fickian. The diffusion coefficient and saturated moisture content showed variation with absorption-desorption cycling. A finite element-based methodology incorporating moisture history was developed to predict the cyclic moisture concentration. A comparison is made between the new modelling methodology and a similar method that neglects the moisture history dependence. It was seen that the concentration predictions based on non-history dependent diffusion characteristics resulted in over-prediction of the moisture concentration in cyclic conditioning of adhesive joints. The proposed method serves as the first step in the formulation of a general methodology to predict the moisture dependent degradation and failure in adhesives

Fracture mechanics and damage mechanics based fatigue lifetime prediction of adhesively bonded joints subjected to variable amplitude fatigue

The first part of the paper describes an investigation into the behaviour of adhesively bonded single lap joints (SLJs) subjected to various types of variable amplitude fatigue (VAF) loading. It was seen that a small proportion of fatigue cycles at higher fatigue loads could result in a significant reduction in the fatigue life. Palmgren-Miner's damage sum tended to be less than 1, indicating damage accelerative load interaction effects. In the second part of the paper, fracture mechanics (FM) and damage mechanics (DM) approaches are used to predict the fatigue lifetime for these joints. Two FM based approaches were investigated, which differed with respect to the cycle counting procedure, however, both approaches were found to under-predict the fatigue lifetime for all the types of spectra used. This was attributed to the inability of the FM based models to simulate the crack initiation phase. A DM based approach was then used with a power law relationship between equivalent plastic strain and the damage rate. Good predictions were found for most of the spectra, with a tendency to over-predict the fatigue life

Environmentally-friendly surface treatments

The presentation will focus upon both existing and novel developmental processes for the replacement of the hexavalent chromium containing 40/50V Bengough-Stuart anodise (CAA), with particular emphasis on their resultant performance in structurally bonded systems. Two systems of particular interest are based upon a phosphoric acid based electrolytic deoxidiser (EPAD) studied in combination with a standard sulphuric acid anodise and an alternating current-direct current phosphoric-sulphuric (ACDCPSAA) anodise in a benign electrolyte. It has been shown that the EPAD provides an open porous structure in order to enhance adhesion to the modified sulphuric acid anodised (SAA) surface. Additionally, a post anodising (PAD) treatment has been used to further aid structural adhesion in combination with the aforementioned processes. As a control, the standard 40/50V Bengough-Stuart chromic acid anodising (CAA) has been used as a baseline performance indicator in adhesion tests. Adhesion levels have been established using single lap shear and modified wedge test configurations. Overall, excellent initial joint strengths and durability have been found with both EPAD and ACDCPSAA, suggesting that these environmentally benign treatments may be used as possible drop-in replacements for the currently used CAA process

Moisture absorption-desorption effects in adhesive joints

This paper presents a study of moisture absorption-desorption effects in single lap adhesive joints. Experiments were carried out to characterise the moisture uptake of the single part epoxide adhesive, FM73. Tensile testing of single lap joints manufactured from aluminium alloy 2024 T3 and O and FM73 adhesive was carried out after the joints were exposed to different conditioning environments. The experimental results revealed that the failure strength of the single lap joints with 2024 T3 adherends progressively degraded with time when conditioned at 50°C, immersed in water. However, the joint strength almost completely recovered after moisture was desorbed. The single lap joints with 2024 O adherends showed decreased strength for 28 days of conditioning, after which strength recovered, reaching a plateau after 56 days. Again, strength almost completely recovered on desorption of moisture. The strength recovery of the joints, after desorption of moisture, showed that the degradation of the adhesive was largely reversible. Analysis of the failure surfaces revealed that the dry joints failed cohesively in the adhesive layer and that the failure path moved towards the interface after conditioning. The failure mode then reverted back to cohesive failure after moisture desorption

Unified methodology for the prediction of the fatigue behaviour of adhesively bonded joints

A unified model is proposed to predict the fatigue behaviour of adhesively bonded joints. The model is based on a damage mechanics approach, wherein the evolution of fatigue damage in the adhesive is defined as a power law function of the micro-plastic strain. The model is implemented as an external subroutine for commercial finite element analysis software. Three dimensional damage evolution and crack propagation were simulated using this method and an element deletion technique was employed to represent crack propagation. The model was able to predict the damage evolution, crack initiation and propagation lives, strength and stiffness degradation and the backface strain during fatigue loading. Hence the model is able to unify previous approaches based on total life, strength or stiffness wearout, backface strain monitoring and crack initiation and propagation modelling. A comparison was made with experimental results for an epoxy bonded aluminium single lap joint and a good match was found

Strategies for the replacement of chromic acid anodising for the structural bonding of aluminium alloys

The 40/50V Bengough-Stuart chromic acid anodise process is widely used in demanding applications as a prebond treatment. This process has a number of disadvantages and its replacement is the subject of much interest in the aerospace, automotive and defence sectors, amongst others. This paper details a number of modifications to the standard boric-sulphuric acid anodising (BSAA) process specifically to achieve satisfactory structural bond performance. These included: variations in the deoxidiser and anodising parameters, and; the use of a post anodising dip. It has been demonstrated in these studies that there are three possible methods of providing excellent durability using a variation of the standard BSAA process: the use of an electrolytic phosphoric acid deoxidiser (EPAD); a high temperature anodise at 35°C, and; the use of a post anodise phosphoric acid dip (PAD)