Multi-objective robust design of energy-absorbing components using coupled process–performance simulations

The stochastic uncertainties associated with the material, process and product are represented and propagated to process and performance responses. A finite element-based sequential coupled process–performance framework is used to simulate the forming and energy absorption responses of a thin-walled tube in a manner that both material properties and component geometry can evolve from one stage to the next for better prediction of the structural performance measures. Metamodelling techniques are used to develop surrogate models for manufacturing and performance responses. One set of metamodels relates the responses to the random variables whereas the other relates the mean and standard deviation of the responses to the selected design variables. A multi-objective robust design optimization problem is formulated and solved to illustrate the methodology and the influence of uncertainties on manufacturability and energy absorption of a metallic double-hat tube. The results are compared with those of deterministic and augmented robust optimization problems.     

The effects of processing technology on the patulin content of juice during commercial apple juice concentrate production

 The effects of different treatments on the patulin content of apple juice during the production of industrial apple juice concentrate were investigated. Conventional clarification using a rotary vacuum precoat filter was found to be more effective than using ultrafiltration for the removal of patulin from apple juice. The average losses of patulin were 39% and 25% for conventional clarification and filtration, and ultrafiltration, respectively. Washing and handling appeared to be the most critical steps in removing patulin from apples since up to 54% could be removed using high-pressure water spraying. Received: 22 January 1998 / Revised version: 21 April 1998     

Innovation in hydrogen production

In this study, the critical perspectives of innovation are introduced for specifically for hydrogen production under a new concept (so-called: 18S concept), covering source, system, service, scope, staff, scale-up, safety, scheme, sector, solution, stakeholder, standardization, subsidy, stimulation, structure, strategy, support and sustainability. The roles of these specific conceptual items are discussed, and their importance is highlighted. Furthermore, the innovative methods in hydrogen production are assessed by using a ranking method for comparison and evaluation purposes. The results show that renewable sources, particularly hydro, geothermal and solar show a unique potential to support these innovative H₂ production systems. When the H₂ production systems are compared, the ones supporting heat recovery (thermal) and the photonic based options show better performance in terms of emissions, cost and efficiency.     

Investigation of carbon contamination in lost foam castings of low carbon steel

Lost foam casting(LFC) process is a special casting method in which polymeric foam patterns with refractory coatings are utilized as a mould component. In this work, four types of foam: expandable polyethylene(EPE), expandable polypropylene(EPP) and expandable polystyrene(EPS) foams with two different densities were employed as pattern materials. LFC and conventional green sand mould casting methods were used to cast a low carbon steel, A216 Grade WCB. Both casting processes were carried out at 1,580 °C. Chemical analysis results showed that the carbon contamination level was high and was influenced by pattern type. Metallographic investigations revealed a significant increase in the percentage of pearlite phase in all LFC samples. Densities of manufactured samples were calculated in order to evaluate porosity of the products. It was determined that the densities of the LFC samples were lower than the green sand mould cast reference sample(RS). Vickers hardness tests were also carried out and increments in hardness values with increased carbon content was observed.     

How can we improve foodborne disease surveillance systems: A comparison through EU and US systems

Foodborne diseases remain a major threat to global public health. Problems in detecting the threats at early stages in the supply chain due to defects in surveillance systems cannot be ignored. The primary goal of this article is to evaluate the capabilities of foodborne disease surveillance systems known for their effectiveness and functionality in order to highlight solutions for preventing and managing the outbreaks more effectively. For this purpose, early detection, notification and monitoring systems of the European Union (EU) and the United States were compared in terms of capability gaps and critical needs via an in-depth examination of two standout outbreaks.     

Partial mitral homograft: a new technique for mitral valve repair

Partial mitral homograft was used in 22 patients with localized lesions contraindicating a conventional valve repair. The etiologies of valve disease were: calcified rheumatic stenosis (n=14) and acute bacterial endocarditis (n=8). One patient died three months after surgery from cancer. Another patient required reoperation for residual stenosis 14 months postoperatively. All other patients had an excellent functional result with 19 patients in sinus rhythm. In this series, partial homograft replacement of the mitral valve significantly extended the possibilities of reconstructive surgery.     

Analyzing and comparing Montgomery multiplication algorithms

Montgomery multiplication methods constitute the core of modular exponentiation, the most popular operation for encrypting and signing digital data in public-key cryptography. In this article, we study the operations involved in computing the Montgomery product, describe several high-speed, space-efficient algorithms for computing MonPro(a, b), and analyze their time and space requirements. Our focus is to collect several alternatives for Montgomery multiplication, three of which are new. However, we do not compare the Montgomery techniques to other modular multiplication approaches     

RLC-ladder-network synthesis: signal-flow-graph approach

Using signal-flow graphs, a theorem is proved which gives the immittance functions of the ladder network of which the voltage transfer function is to be realised, and then the realisation of a given voltage transfer function by the use of this theorem is illustrated.     

New transformations in signal-flow graphs

New transformations are given which make it possible to transform a given signal-flow graph to any other one with the same nodes and the same node variables. Such transformations are useful in network synthesis by signal-flow graphs.