The high renaissance properties of porous three dimensional graphene using one step reduction and its application in flexible conductor

 A super conductive graphene with continuous three dimensional (3D) porous structures that can potentially be used as flexible conductors has been produced by one step reduction of graphene oxide (GO) film. The high renaissance properties have been demonstrated by mechanical and electrical results where a noticeable increase in the electrical conductivity to 3850 S/cm has been demonstrated after embedding the 3D graphene foam into nearly insulated polydimethylsiloxane (PDMS). The graphene integrated PDMS film has a higher strain up to 100% elongation compared with the strain of only 60% for PDMS. Fourier transform infrared (FTIR) and x-ray photoemission spectroscopy (XPS) results reveal that most oxidized groups have been removed, which contributes to the renaissance of most outstanding properties of graphene because of the recovery of sp2 carbon structures.

Modeling the effect of lead-free soldering on flexible substrates

Flexible Circuit Boards (FPCs) are now being widely used in the electronic industries especially in the areas of electronic packages. Due to European lead-free legislation which has been implemented since July 2006, electronic packaging industries have to switch to use in the lead-free soldering technology. This change has posed a number of challenges in terms of development of lead-free solders and compatible substrates. An increase of at least 20-50 degrees in the reflow temperature is a concern and substantial research is required to investigate a sustainable design of flexible circuit boards as carrier substrates. This paper investigates a number of design variables such as copper conductor width, type of substrate materials, effect of insulating materials, etc. Computer modeling has been used to investigate thermo-mechanical behavior, and reliability, of flexible substrates after they have been subjected to a lead- free solder processing. Results will show particular designs that behave better for a particular rise in peak reflow temperature. Also presented will be the types of failures that can occur in these substrates and what particular materials are more reliable.

Challenging endoscopy reprocessing guidelines: a prospective study investigating the safe shelf life of flexible endoscopes in a tertiary gastroenterology unit.

Professional prac− tice guidelines for endoscope reprocessing re− commend reprocessing endoscopes between each case and proper storage following repro− cessing after the last case of the list. There is lim− ited empirical evidence to support the efficacy of endoscope reprocessing prior to use in the first case of the day; however, internationally, many guidelines continue to recommend this practice. The aim of this study is to estimate a safe shelf life for flexible endoscopes in a high−turnover gastroenterology unit. Materials and methods: In a prospective obser− vational study, all flexible endoscopes in active service during the 3−week study period were mi− crobiologically sampled prior to reprocessing be− fore the first case of the day (n = 200). The main outcome variables were culture status, organism cultured, and shelf life. Results: Among the total number of useable samples (n = 194), the overall contamination rate was 15.5 %, with a pathogenic contamination rate of 0.5 %. Mean time between last case one day and reprocessing before the first case on the next day (that is, shelf life) was 37.62 h (SD 36.47). Median shelf life was 18.8 h (range 5.27± 165.35 h). The most frequently identified organ− ism was coagulase−negative Staphylococcus, an environmental nonpathogenic organism. Conclusions: When processed according to es− tablished guidelines, flexible endoscopes remain free from pathogenic organisms between last case and next day first case use. Significant re− ductions in the expenditure of time and resources on reprocessing endoscopes have the potential to reduce the restraints experienced by high−turnover endoscopy units and improve ser− vice delivery.

Object-centric process models and the design of flexible processes

Mainstream business process modelling techniques promote a design paradigm wherein the activities to be performed within a case, together with their usual execution order, form the backbone of a process model, on top of which other aspects are anchored. This paradigm, while eective in standardised and production-oriented domains, shows some limitations when confronted with processes where case-by-case variations and exceptions are the norm. In this thesis we develop the idea that the eective design of exible process models calls for an alternative modelling paradigm, one in which process models are modularised along key business objects, rather than along activity decompositions. The research follows a design science method, starting from the formulation of a research problem expressed in terms of requirements, and culminating in a set of artifacts that have been devised to satisfy these requirements. The main contributions of the thesis are: (i) a meta-model for object-centric process modelling incorporating constructs for capturing exible processes; (ii) a transformation from this meta-model to an existing activity-centric process modelling language, namely YAWL, showing the relation between object-centric and activity-centric process modelling approaches; and (iii) a Coloured Petri Net that captures the semantics of the proposed meta-model. The meta-model has been evaluated using a framework consisting of a set of work ow patterns. Moreover, the meta-model has been embodied in a modelling tool that has been used to capture two industrial scenarios.