Formation and analysis of stack cracks in a pipeline steel

Extensive cracking of the type known as stack cracking was demonstrated in a cathodically charged X65 microalloyed pipeline steel containing a weldment. It is shown that the formation and propagation of rolling-plane cracks, which constitute the primary stages of the stack cracking, is due to local concentration of hydrogen gas pressure and a lowering of the cohesive strength of a number of interfaces by hydrogen. The characteristic S-shape of individual cracks which occurred during the linking up of cracks was attributed to stress interactions at crack tips and cleavage cracking normal to the rolling plane. An explanation of hydrogen embrittlement fracture is given in terms of electronic state modifications of the steel, including charge polarization.     

Gamma irradiation of (styrene butadiene rubber)/(devulcanized waste rubber) blends modified by organoclay

In this study, the physicomechanical properties and morphology evolution of irradiated (styrene butadiene rubber)/(devulcanized waste rubber)/(organically modified montmorillonite) nanocomposites were realized. The improvement in the physicomechanical properties provides a possible mechanism on how organically modified montmorillonite influences the general properties of irradiated nanocomposites. X‐ray diffraction data illustrated that there is an increase in the basal spacing of sodium montmorillonite clay due to modification and/or polymer intercalation. The results of mechanical properties showed that the as‐prepared nanocomposites have superior irradiation‐resistant properties to the (styrene butadiene rubber)/(devulcanized waste rubber) blend. J. VINYL ADDIT. TECHNOL., 24:50–57, 2018. © 2015 Society of Plastics Engineers     

Multivariate High-Order Attacks of Shuffled Tables Recomputation

Masking schemes based on tables recomputation are classical countermeasures against high-order side-channel attacks. Still, they are known to be attackable at order d in the case the masking involves d shares. In this work, we mathematically show that an attack of order strictly greater than d can be more successful than an attack at order d. To do so, we leverage the idea presented by Tunstall, Whitnall and Oswald at FSE 2013: We exhibit attacks which exploit the multiple leakages linked to one mask during the recomputation of tables. Specifically, regarding first-order table recomputation, improved by a shuffled execution, we show that there is a window of opportunity, in terms of noise variance, where a novel highly multivariate third-order attack is more efficient than a classical bivariate second-order attack. Moreover, we show on the example of the high-order secure table computation presented by Coron at EUROCRYPT 2014 that the window of opportunity enlarges linearly with the security order d. These results extend that of the CHES ’15 eponymous paper. Here, we also investigate the case of degree one leakage models and formally show that the Hamming weight model is the less favorable to the attacker. Eventually, we validate our attack on a real ATMEL smartcard.     

Liver is not essential for solute transport during peritoneal dialysis

Based on theoretical calculations on solute exchange capacities of various peritoneal tissues, the liver has been predicted to account for up to 43% of the permeability-surface area product (PS) of the entire peritoneal "membrane" for a small solute (sucrose) during peritoneal dialysis (PD). In these calculations, the abdominal wall and the diaphragm were found to contribute only approximately 10 to 15% of the total PS. However, evisceration has in previous studies been shown to affect the PS characteristics during PD only marginally (10 to 30%). In such evisceration experiments the liver was usually not removed, and therefore it has been suggested that an intact liver might have significantly contributed to the solute exchange under these premises. We assessed the peritoneal PS of 51Cr-EDTA (constantly infused intravenously) and the plasma-to-peritoneal clearance (ClB-->P) of 125I-human serum albumin (RISA) (given as an i.v. bolus) in Wistar rats during acute PD. In one group of rats the liver surface was sealed off using Histoacrylate glue (N = 6) and in another group a 90% hepatectomy was performed, the remaining portion of the liver, usually the right lower lobe, being sealed off by glue (N = 6). A third group was sham operated to serve as control (N = 12). The PS for 51Cr-EDTA was 0.32 +/- 0.03(+/- SE) ml. min-1 (N = 12) during control, 0.32 +/- 0.04 ml.min-1 after "sealing" of the liver surface (N = 6, P > 0.1) and 0.40 +/- 0.03 after hepatectomy (N = 6, P > 0.1), that is, remained unchanged after experimental intervention. The CIB-->P of RISA during control was 5.88 +/- 1.0 microliter.min-1 (N = 10), and was not altered after hepatectomy, 6.17 +/- 0.48 microliters.min-1 (N = 5, P > 0.1), but slightly increased after liver surface sealing (9.69 +/- 1.09 microliters.min-1, N = 5, P < 0.05). In conclusion, the present experiments indicate that the liver does not play an essential role in the overall solute exchange between the plasma and the peritoneal cavity (PC) during PD.     

Integrating SLAM and gas distribution mapping (SLAM-GDM) for real-time gas source localization

Gas distribution mapping (GDM) learns models of the spatial distribution of gas concentrations across 2D/3D environments, among others, for the purpose of localizing gas sources. GDM requires run-time robot positioning in order to associate measurements with locations in a global coordinate frame. Most approaches assume that the robot has perfect knowledge about its position, which does not necessarily hold in realistic scenarios. We argue that the simultaneous localization and mapping (SLAM) algorithm should be used together with GDM to allow operation in an unknown environment. This paper proposes an SLAM-GDM approach that combines Hector SLAM and Kernel DM?+?V through a map merging technique. We argue that Hector SLAM is suitable for the SLAM-GDM approach since it does not perform loop closure or global corrections, which in turn would require to re-compute the gas distribution map. Real-time experiments were conducted in an environment with single and multiple gas sources. The results showed that the predictions of gas source location in all trials were often correct to around 0.5–1.5 m for the large indoor area being tested. The results also verified that the proposed SLAM-GDM approach and the designed system were able to achieve real-time operation.     

Low‐Energy Room‐Temperature Healing of Cellular Metals

Healing metallic materials involves high temperatures and large energy inputs. This work demonstrates rapid, effective, low‐energy, and room‐temperature healing of metallic materials by using electrochemistry and polymer‐coated cellular nickel to mimic the transport‐mediated healing of bone. The polymer coating enables selective healing only at the fracture site, electrochemical reactions transport metal ions from a metal source to fractured areas, and the cellular structure of the metal allows facile ion transport to healing sites and effective recovery of strength and toughness when the cellular metal is subjected to three types of damage (scission fracture, tensile failure, and plastic deformation). Using this strategy, samples fractured in tension and by scission recover 100% of their tensile strength in as little as 10 and 4 h of healing. The healing process is stochastic, thus a statistical method is used to quantify and predict the likelihood of achieving target healing strengths based on energy input. This electrochemistry‐based approach enables the first demonstration of room‐temperature healing of structural metallic materials and requires several orders of magnitude less energy than many previously reported metal healing techniques.     

Risk-Based Design of Flood Control Systems Considering Multiple Dependent Uncertainties

Due to random behavior of flood events and inaccuracies in measurements, design, analysis, and operation of flood control systems are subjected to several uncertainties. An important aspect in developing stochastic models for evaluating and analyzing more than one uncertainty is the dependence or independence of them. In flood control projects, hydrologic, hydraulic, geotechnical, and economic uncertainties are important considerations. In this paper, a stochastic Monte-Carlo simulation – optimization modeling approach is described for risk-based design of flood control levees (as a common structural flood control measure): considering multiple dependent uncertainties. It has been applied to the Leaf River reach in Hattiesburg, Mississippi for testing and evaluation of modeling results. Unlike a deterministic model that yields just one set of values for system dimensions, the stochastic model solution gives a range of values for each of them. One of the major reasons for limited field application of uncertainty analysis is difficulties in performing the modeling results in real world contexts. For closing the gap between theory and reality, design charts are developed in this study. This helps decision makers in identifying design values with desired and accepted risks.     

Synthetically engineered microbes reveal interesting principles of cooperation

Cooperation is ubiquitous in biological systems. However, if natural selection favors traits that confer an advantage to one individual over another, then helping others would be paradoxical. Nevertheless, cooperation persists and is critical in maintaining homeostasis in systems ranging from populations of bacteria to groupings of mammals. Developing an understanding of the dynamics and mechanisms by which cooperation operates is critical in understanding ecological and evolutionary relationships. Over the past decade, synthetic biology has emerged as a powerful tool to study social dynamics. By engineering rationally controlled and modulatable behavior into microbes, we have increased our overall understanding of how cooperation enhances, or conversely constrains, populations. Furthermore, it has increased our understanding of how cooperation is maintained within populations, which may provide a useful framework to influence populations by altering cooperation. As many bacterial pathogens require cooperation to infect the host and survive, the principles developed using synthetic biology offer promise of developing novel tools and strategies to treat infections, which may reduce the use of antimicrobial agents. Overall, the use of engineered cooperative microbes has allowed the field to verify existing, and develop novel, theories that may govern cooperative behaviors at all levels of biology.

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Engineered disulfide bonds in recombinant human interferon-{gamma}: the impact of the N-terminal helix A and the AB-loop on protein stability

Insertion sites for cysteines with optimal stereochemistry forthe formation of unstrained disulfide bridges were identifiedin recombinant human interferon- (rhu-IFN-) by computer modelling.We have engineered two different disulfide cross-linked mutants,containing a pair of symmetry-related disulfide bonds, whichstabilize the N-termini of both monomers of the homodimenc protein.Mutations E7C and S69C allow the formation of an intramonomerdisuffide bond between helices A and D. In contrast, the A17Cand H111C mutations lead to a covalent cross-link between bothmonomers. The AB-loop is linked to helix F. The fluorescenceproperties of native and disulfide cross-linked proteins werestudied as a function of guanidine hydrochloride concentration.Melting temperatures (T_m) were calculated from the decreasein CD ellipticity at 220 nm. The induction of the antiviraleffect was measured using A549 fibroblast cells infected withencephalomyocarditis virus. The ability to induce the expressionof the HLA-DR antigen in Colo 205 cells was determined by fluorescence-activatedcell scanning analysis. The stability of both mutants was stronglyenhanced against temperature- and cosolvent-induced unfolding.The T_m of mutant IFN- E7C/S69C was 15°C. All measured biologicalactivities of this mutant were equal to wild type. In the caseof the other mutant IFN- A17C/H111C, the T_m value was 25°C.This mutation abolishes nearly the entire biological activity(<1%) with no detectable changes of secondary structure inthe CD spectrum. Our results illustrate the importance of theN-terminal helix A and the AB-loop for the unfolding pathwayand thermodynamic stability of rhu-IFN-.