METHOD FOR REFERENCE-BASED MANUFACTURING COST ESTIMATION – EVALUATION STUDY USING A PROTOTYPE

Within product development, manufacturing cost estimation provides a sound basis for design and management decisions. This secures companies profitability, but the effort is high and deep knowledge at the interface of design, manufacturing and costs is needed. These issues can be eased with automation enabled by semantic technologies. Therefore, the authors developed a method for reference-based manufacturing cost estimation and created a prototype. This research evaluates the method and the prototype. Observation, interview and questionnaire were conducted with ten experienced cost engineers at a large German manufacturing company. Based on its results, the study shows the methods contribution to lower estimation effort, while the impact on transparency and the knowledge base was only partly verified. The method steps show different automation potential, so an incremental automation should be considered. Even though semantic technologies show high potential for identifying reference system elements in this study, the limiting factor for automation in manufacturing cost estimation remains the low availability of product and manufacturing information and missing knowledge of its connection within product development

Mechanical Characterisation of Bond Formation during Overprinting of PEEK Laminates

The latest generation of high-temperature 3D printers enables the production of complex struc-tural components from aerospace-grade thermoplastics such as PEEK (polyether ether ketone). However, adding long or continuous fibres is currently limited, and thermal stresses introduced during the process restrict the maximum part dimensions. Combining 3D-printed components with continuous fibre-reinforced components into one hybrid structure has the potential to overcome such limitations. This work aims to determine whether in situ bonding between PEEK laminates and PEEK 3D printing during overprinting is feasible and which process parameters are significantly responsible for the bonding quality. To this end, the bonding is analysed ex-perimentally in two steps. Firstly, the influence of the process parameters on the thermal history and the strength of the bond is investigated. In the second step, a detailed investigation of the most critical parameters is carried out. The investigation showed the feasibility of overprinting with bonding strengths of up to 15 MPa. It was shown that the bonding strength depends pri-marily on the temperature in the interface. Additionally, the critical parameters to control the process were identified. The process influences that were displayed form the basis for future hy-brid component and process designs

OVERPRINTING OF LARGE-SCALE THERMOPLASTIC COMPOSITES IN FGF-PROCESS USING LOCAL PREHEATING

The rise of large-scale systems for Fused Granular Fabrication (FGF) of thermoplastics opens up new possibilities for manufacturing thermoplastic composites. One promising approach is the overprinting of continuous fibre-reinforced laminates to increase complexity and functionality of highperformance structures. However, overprinting aerospace-grade materials like Polyether Ether Ketone (PEEK) requires high substrate and ambient temperatures. The large-scale systems lack the possibility to use heated build chambers and can therefore overprint only to a limited extent. This work investigates the possibility of equipping the printer system with local preheating for high-temperature substrates. Therefore, a heating concept using hot air heating is developed and evaluated regarding heating efficiency and the influence of heating on print quality. The study was performed on a modified desktop printer, with which temperature measurements and mechanical testing were carried out. Based on this study, a prototype of a local preheating for a large-scale FGF system was designed, suitable for multiaxis overprinting PEEK laminates. The heating capability of high-temperature substrates was evaluated. Results show preheating temperatures of over 200 °C and significant improvement of the material quality of printed PEEK. The developed prototype forms the basis for further process and technology development fur future composite manufacturing

Product-Production-CoDesign: An Approach on Integrated Product and Production Engineering Across Generations and Life Cycles

Shorter product life cycles and high product variance nowadays require efficient engineering of products and production systems. Hereby a further challenge is that costs over the entire life cycle of the product and production system are defined early in the process. Existing approaches in literature and practice such as simultaneous engineering and design for manufacturing incorporate aspects of production into product engineering. However, these approaches leave potential for increasing efficiency unused because knowledge from past generations of products, production systems, and business models is not stored and reused in a formalized way and future generations are not considered in the respective current engineering process. This article proposes an approach for integrated product and production engineering across generations and life cycles of products and production systems. This includes the consideration of related business models to successfully establish the products on the market as well as the anticipation of future product and production system characteristics. The presented approach can reduce both development and manufacturing costs as well as time to market and opens the vast technological potential for product design to achieve additional customer benefits. Three case studies elaborate on aspects of the proposed approach and present its benefits

Arctic Seafloor Integrity Cruise No. MSM95 – (GPF 19-2_05)

The main aim of the MSM95 research expedition was to investigate and map physical impacts on the arctic seafloor in two distinct and contrasting Arctic areas (The Svalbard shelf edge and the HAUSGARTEN time series stations in the FRAM strait) with a range of research equipment. A ‘nested’ data approach was conducted in each research area, with broad seafloor mapping conducted initially with the R/V MARIA S. MERIAN onboard acoustic systems (The EM122 and EM712 bathymetric systems), followed by focused subsequent mapping conducted by PAUL 3000 automated underwater vehicle (AUV) sidescan and camera deployments, Ocean Floor Observation and Bathymetry System (OFOBS) towed sidescan and camera trawls and finally with very high resolution investigations conducted with a new mini-ROV launched directly from the OFOBS for close seafloor visual analysis. These data will be used to produce spatial distribution maps of iceberg and fishery impacts on the seafloor at three locations to the north, south and west of the Svalbard Archipelago, as well as maps of drop stone and topography variations across several of the HAUSGARTEN stations

Forward-Secure 0-RTT Goes Live: Implementation and Performance Analysis in QUIC

Modern cryptographic protocols, such as TLS 1.3 and QUIC, can send cryptographically protected data in zero round-trip times (0-RTT) , that is, without the need for a prior interactive handshake. Such protocols meet the demand for communication with minimal latency, but those currently deployed in practice achieve only rather weak security properties, as they may not achieve forward security for the first transmitted payload message and require additional countermeasures against replay attacks. Recently, 0-RTT protocols with full forward security and replay resilience have been proposed in the academic literature. These are based on puncturable encryption, which uses rather heavy building blocks, such as cryptographic pairings. Some constructions were claimed to have practical efficiency, but it is unclear how they compare concretely to protocols deployed in practice, and we currently do not have any benchmark results that new protocols can be compared with. We provide the first concrete performance analysis of a modern 0-RTT protocol with full forward security, by integrating the Bloom Filter Encryption scheme of Derler et al. (EUROCRYPT 2018) in the Chromium QUIC implementation and comparing it to Google\u27s original QUIC protocol. We find that for reasonable deployment parameters, the server CPU load increases approximately by a factor of eight and the memory consumption on the server increases significantly, but stays below 400 MB even for medium-scale deployments that handle up to 50K connections per day. The difference of the size of handshake messages is small enough that transmission time on the network is identical, and therefore not significant. We conclude that while current 0-RTT protocols with full forward security come with significant computational overhead, their use in practice is not infeasible, and may be used in applications where the increased CPU and memory load can be tolerated in exchange for full forward security and replay resilience on the cryptographic protocol level. Our results also serve as a first benchmark that can be used to assess the efficiency of 0-RTT protocols potentially developed in the future

Factors affecting the nucleus-independent chemical shift in NMR studies of microporous carbon electrode materials

NMR spectroscopy has recently emerged as a powerful method for studying electrolyte species in microporous carbon electrodes used in capacitive energy storage devices. Key to this approach is the nucleus-independent chemical shift (NICS) which enables adsorbed species to be distinguished from those in the bulk electrolyte. The magnitude of the NICS is well known to be dependent on the distance of the adsorbed species from the carbon surface, and has therefore been used in several studies as a probe of the carbon pore size. However, the NICS can also be influenced by a number of other structural and chemical factors which are not always taken into account. To investigate this, we have carried out a systematic study of the factors influencing the NICS of aqueous electrolyte species adsorbed on polymer-derived activated carbon in the absence of an applied potential. We find that a number of effects arising from both the carbon structure as well as the behaviour and chemical properties of the electrolyte species can contribute to the observed NICS. In turn, the measurement of these effects provides important information about ion behaviour and reveals significant differences in the adsorption behaviour of different ions in the absence of an applied potential. In accordance with several computational studies, we find experimental evidence that the local concentration of spontaneously adsorbed alkali ions decreases with the pore size. This has potential implications for understanding the molecular-level mechanism of charge storage in capacitive devices

Amaze: a randomized controlled trial of adjunct surgery for atrial fibrillation

OBJECTIVES: Atrial fibrillation (AF) reduces survival and quality of life (QoL). It can be treated at the time of major cardiac surgery using ablation procedures ranging from simple pulmonary vein isolation to a full maze procedure. The aim of this study is to evaluate the impact of adjunct AF surgery as currently performed on sinus rhythm (SR) restoration, survival, QoL and costeffectiveness. METHODS: In a multicentre, Phase III, pragmatic, double-blinded, parallel-armed randomized controlled trial, 352 cardiac surgery patients with >3 months of documented AF were randomized to surgery with or without adjunct maze or similar AF ablation between 2009 and 2014. Primary outcomes were SR restoration at 1 year and quality-adjusted life years at 2 years. Secondary outcomes included SR at 2 years, overall and stroke-free survival, medication, QoL, cost-effectiveness and safety. RESULTS: More ablation patients were in SR at 1 year [odds ratio (OR) 2.06, 95% confidence interval (CI) 1.20–3.54; P = 0.009]. At 2 years, the OR increased to 3.24 (95% CI 1.76–5.96). Quality-adjusted life years were similar at 2 years (ablation - control -0.025, P = 0.6319). Significantly fewer ablation patients were anticoagulated from 6 months postoperatively. Stroke rates were 5.7% (ablation) and 9.1% (control) (P = 0.3083). There was no significant difference in stroke-free survival [hazard ratio (HR) = 0.99, 95% CI 0.64–1.53; P = 0.949] nor in serious adverse events, operative or overall survival, cardioversion, pacemaker implantation, New York Heart Association, EQ-5D-3L and SF-36. The mean additional ablation cost per patient was £3533 (95% CI £1321–£5746). Cost-effectiveness was not demonstrated at 2 years. CONCLUSIONS: Adjunct AF surgery is safe and increases SR restoration and costs but not survival or QoL up to 2 years. A continued follow-up will provide information on these outcomes in the longer term