Effects of chemical structure and morphology of graphene-related materials (GRMs) on melt processing and properties of GRM/polyamide-6 nanocomposites

In this work, different graphene-related materials (GRMs) and polyamide-6 (PA6) were melt compounded by twin screw extrusion. The GRMs prepared were graphene nanoplatelets (GNPs), graphene oxide (GO), reduced graphene oxide (rGO) and silane functionalised reduced graphene oxide (f-rGO). The GRMs had comparable lateral size (20-30μm), but different thickness and surface chemistry which resulted in different behaviour in processing of melt flow, maximum loading in the PA6 matrix (15%wt for GNPs, 10%wt for GO, 2%wt for rGO and 2.5%wt for f-rGO) as well as mechanical properties. A second extrusion phase produced formulations with lower concentration of GRMs. In the case of f-rGO/PA6, the melt flow index increased by over 76% at 0.5%wt loading compared with the pure PA6 resin, facilitating processing and dispersion of the flakes within the matrix and increasing the elastic modulus and tensile strength by 39%. However, high filler content above 10% has been achieved only for GNPs improving the elastic modulus by 50% at 15%wt

Live Heap Space Analysis for Languages with Garbage Collection

The peak heap consumption of a program is the maximum size of the live data on the heap during the execution of the program, i.e., the minimum amount of heap space needed to run the program without exhausting the memory. It is well-known that garbage collection (GC) makes the problem of predicting the memory required to run a program difficult. This paper presents, the best of our knowledge, the first live heap space analysis for garbage-collected languages which infers accurate upper bounds on the peak heap usage of a program’s execution that are not restricted to any complexity class, i.e., we can infer exponential, logarithmic, polynomial, etc., bounds. Our analysis is developed for an (sequential) object-oriented bytecode language with a scoped-memory manager that reclaims unreachable memory when methods return. We also show how our analysis can accommodate other GC schemes which are closer to the ideal GC which collects objects as soon as they become unreachable. The practicality of our approach is experimentally evaluated on a prototype implementation.We demonstrate that it is fully automatic, reasonably accurate and efficient by inferring live heap space bounds for a standardized set of benchmarks, the JOlden suite

Test Data Generation of Bytecode by CLP Partial Evaluation

We employ existing partial evaluation (PE) techniques developed for Constraint Logic Programming (CLP) in order to automatically generate test-case generators for glass-box testing of bytecode. Our approach consists of two independent CLP PE phases. (1) First, the bytecode is transformed into an equivalent (decompiled) CLP program. This is already a well studied transformation which can be done either by using an ad-hoc decompiler or by specialising a bytecode interpreter by means of existing PE techniques. (2) A second PE is performed in order to supervise the generation of test-cases by execution of the CLP decompiled program. Interestingly, we employ control strategies previously defined in the context of CLP PE in order to capture coverage criteria for glass-box testing of bytecode. A unique feature of our approach is that, this second PE phase allows generating not only test-cases but also test-case generators. To the best of our knowledge, this is the first time that (CLP) PE techniques are applied for test-case generation as well as to generate test-case generators

Professional Quality of Life and Emergency Department Nurses\u27 Communication Patterns

The purpose of this mixed methods embedded design study was to examine relationships between compassion satisfaction, burnout, compassion fatigue/secondary trauma, and perceived levels of communication difficulty in emergency room nurses employed at a health care system. Quantitative data was collected from a purposive sample of 43 emergency room nurses using the Professional Quality of Life Scale (ProQOL), the Silencing Response Scale, and a demographic form. The study\u27s embedded qualitative component was participants\u27 experiences with traumatic cases in the emergency room. Qualitative data was collected via telephone interview with 10 emergency room nurses obtained from a subset of the original sample and snowball sampling. The majority of participants reported low levels of compassion satisfaction on the ProQOL subscale (M = 38.63, SD 9.47), low levels of burnout and compassion fatigue/secondary trauma (M=21.4, SD 6.3 and M= 21.1, SD 5.2, respectively). Participants who worked in an urgent care setting scored highest (M= 44.3, SD 4.3) in perceived professional satisfaction in their ability as caregivers. The Silencing Response instrument yielded a mean score of 59.3, indicative of a moderate risk of communication difficulties for the entire sample. A correlation matrix indicated significant positive relationships between subscales of compassion satisfaction, burnout, compassion fatigue/secondary trauma, and the Silencing scale. Multiple regressions were conducted to explore the accuracy of the independent variables of compassion satisfaction, resource availability, burnout, compassion fatigue/secondary trauma, and years of experience as predictors of silencing scores. Partial regression coefficients on three separate models indicate compassion satisfaction, burnout, and compassion fatigue/secondary trauma significantly contribute to the models of predicting silencing response. Telephone interviews themes included pediatric traumas, discomfort, maintaining emotional control, obstructed communication, and deflection. The related themes potential support systems and available resources also potentially addressed decreased professional quality of life in emergency department nurses. This study contributes to the understanding of the relationship between professional quality of life and communication. The identification of relationships between the subscale items in concert with the participant interviews helped justify how coping strategies are implemented and is a first step in addressing deficiencies in communication

Towards a navigational logic for graphical structures

One of the main advantages of the Logic of Nested Conditions, defined by Habel and Pennemann, for reasoning about graphs, is its generality: this logic can be used in the framework of many classes of graphs and graphical structures. It is enough that the category of these structures satisfies certain basic conditions. In a previous paper [14], we extended this logic to be able to deal with graph properties including paths, but this extension was only defined for the category of untyped directed graphs. In addition it seemed difficult to talk about paths abstractly, that is, independently of the given category of graphical structures. In this paper we approach this problem. In particular, given an arbitrary category of graphical structures, we assume that for every object of this category there is an associated edge relation that can be used to define a path relation. Moreover, we consider that edges have some kind of labels and paths can be specified by associating them to a set of label sequences. Then, after the presentation of that general framework, we show how it can be applied to several classes of graphs. Moreover, we present a set of sound inference rules for reasoning in the logic.Peer ReviewedPostprint (author's final draft