An experimental study on the effect of thinning band on the sheet formability in negative incremental forming

In negative incremental forming, a characteristic thinning band occurs on the parts when wall angles approach the maximum obtainable [D. Young, J. Jeswiet, Wall thickness variations in single point incremental forming, Proceedings of the Institute of Mechanical Engineers, Part B, Journal of Engineering Manufacture 218 (2004) 1453–1459]. The effect of this ultra-thin band on the fracture occurrence of part was studied in the current investigation. It was found that the occurrence of a thinning band on the test specimen of a formability test does not mean an effect on the test result. A reduction in the formability due to the occurrence of the thinning band occurs only if the specimen fractures in the flange area. In order to evaluate the real forming limit of a sheet metal, a condition regarding the occurrence of part fracture is proposed.     

Factors affecting the functioning of solid state fluoride galvanic cells

Fluoride galvanic cells employing CaF₂ as electrolyte have not been as extensively employed for thermodynamic characterization of alloys and compounds as the oxide electrolyte cells based on stabilized zirconia. However, CaF₂ galvanic cells have many advantages over oxide electrolyte cells. These advantages, as well as the factors affecting the proper functioning of the CaF₂ cells, are discussed, highlighting the experimental aspects, such as the interfence by the gas phase, choice of the reference electrode, and the volatility and compatibility of the materials.     

Effect of Particle and Carbide Grain Sizes on a HVOAF WC-Co-Cr Coating for the Future Application on Internal Surfaces: Microstructure and Wear

The use of nanoscale WC grain or finer feedstock particles is a possible method of improving the performance of WC-Co-Cr coatings. Finer powders are being pursued for the development of coating internal surfaces, as less thermal energy is required to melt the finer powder compared to coarse powders, permitting spraying at smaller standoff distances. Three WC-10Co-4Cr coatings, with two different powder particle sizes and two different carbide grain sizes, were sprayed using a high velocity oxy-air fuel (HVOAF) thermal spray system developed by Castolin Eutectic-Monitor Coatings Ltd., UK. Powder and coating microstructures were characterized using XRD and SEM. Fracture toughness and dry sliding wear performance at three loads were investigated using a ball-on-disk tribometer with a WC-Co counterbody. It was found that the finer powder produced the coating with the highest microhardness, but its fracture toughness was reduced due to increased decarburization compared to the other powders. The sprayed nanostructured powder had the lowest microhardness and fracture toughness of all materials tested. Unlubricated sliding wear testing at the lowest load showed the nanostructured coating performed best; however, at the highest load this coating showed the highest specific wear rates with the other two powders performing to a similar, better standard.     

Stabilization of Indian peat using alkali-activated ground granulated blast furnace slag

Bulletin of Engineering Geology and the Environment - Peat is an exceptionally problematic soil for construction purposes and is often stabilized by traditional stabilizers (like cement), which...     

Deoxycholate‐Based Glycosides (DCGs) for Membrane Protein Stabilisation

Detergents are an absolute requirement for studying the structure of membrane proteins. However, many conventional detergents fail to stabilise denaturation‐sensitive membrane proteins, such as eukaryotic proteins and membrane protein complexes. New amphipathic agents with enhanced efficacy in stabilising membrane proteins will be helpful in overcoming the barriers to studying membrane protein structures. We have prepared a number of deoxycholate‐based amphiphiles with carbohydrate head groups, designated deoxycholate‐based glycosides (DCGs). These DCGs are the hydrophilic variants of previously reported deoxycholate‐based N‐oxides (DCAOs). Membrane proteins in these agents, particularly the branched diglucoside‐bearing amphiphiles DCG‐1 and DCG‐2, displayed favourable behaviour compared to previously reported parent compounds (DCAOs) and conventional detergents (LDAO and DDM). Given their excellent properties, these agents should have significant potential for membrane protein studies.     

The effect of structural properties and ground motion variables on the global response of structural systems

The uncertainty in the seismic demand of a structure, corresponding to uncertainties in ground motion and in structural properties, needs to be properly characterised in a reliability analysis. In this study, the sensitivity of structural response to major uncertain variables is investigated using the variance-based method in order to determine which variables are most significant. The Sobol’ decomposition, based on a Monte Carlo simulation, is used to decompose the variance of the response into contributions from the individual ground motion and structural properties as input variables. The formulation of a dynamic structural response using the random-vibration theory, based only on the frequency information of the excitation, can provide an important basis for analytical sensitivity analysis of a structural response. The results show that the uncertainties in ground motion are more significant than uncertainties in structural properties for global structural response, especially peak roof displacement and maximum inter-storey drift.     

A Catalyst‐Directed Remote Stereogenic Center Switch During the Site‐Selective Aldol Desymmetrization of Cyclohexanone‐Based Diketones

Site‐selectivity, differentiating members of the same functional group type on one substrate, is an emerging tactic for shortened advanced building block and biomolecule synthesis. Despite its potential, site‐selectivity remains less studied and especially so for ketone‐based substrates. During this work ketone site‐selectivity has been coupled with the chiral amine‐catalyzed aldol desymmetrization of 4‐keto‐substituted cyclohexanones, allowing three stereogenic centers to form in the aldol product while leaving the acyclic ketone unreacted. Unique here, compared to all previous 4‐substituted cyclohexanone desymmetrizations, is the first access to synthetically useful quantities of an epimeric (remote stereogenic center) aldol product. To demonstrate the value of these aldol products, we show their elaboration into eight keto‐acetonide and one keto‐lactone products. All compounds were isolated as single diastereomers and in high ee (≥96%). These efforts represent the first full characterization of aldol products with type III, Figure 2, relative stereochemistry, regardless of the enantiomer formed.

     

Security analysis of pure DDP-based cipher proper for multimedia and ubiquitous device

DDP-64, based on various controlled operations, is a 64-bit Feistel-like block cipher consisting of 10 rounds with a 128-bit key. It was designed to attempt to have a high security level and a high speed performance in hardware on ubiquitous computing systems and multimedia. In this paper, however, we show that DDP-64 doesn’t have a high security level, more precisely, we show that it is vulnerable to related-key differential attack. This attack, which is much faster than the key exhaustive search, requires about 2⁵⁴ data and 2⁵⁴ time complexities. This work is the first known cryptanalytic result on DDP-64 so far.     

Hybrid neural network for prediction of CO<Subscript>2</Subscript> solubility in monoethanolamine and diethanolamine solutions

The solubility of CO₂ in single monoethanolamine (MEA) and diethanolamine (DEA) solutions was predicted by a model developed based on the Kent-Eisenberg model in combination with a neural network. The combination forms a hybrid neural network (HNN) model. Activation functions used in this work were purelin, logsig and tansig. After training, testing and validation utilizing different numbers of hidden nodes, it was found that a neural network with a 3-15-1 configuration provided the best model to predict the deviation value of the loading input. The accuracy of data predicted by the HNN model was determined over a wide range of temperatures (0 to 120 °C), equilibrium CO₂ partial pressures (0.01 to 6,895 kPa) and solution concentrations (0.5 to 5.0M). The HNN model could be used to accurately predict CO₂ solubility in alkanolamine solutions since the predicted CO₂ loading values from the model were in good agreement with experimental data.