Effect of heat treatment on microstructure and corrosion behavior of Al6061 alloy weldment

In this research, the corrosion behavior and microstructure of Al6061 alloy welded by GTAW (Gas tungsten arc welding) and followed by various heat treatments have been investigated. The microstructure of both weld metal (WM) and base metal (BM) was studied using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Corrosion behavior was investigated in 3.5 wt.% NaCl aqueous solution. Results indicated that BM consists of Fe-rich coarse intermetallic particles. These particles were found to act as cathodic regions with respect to surrounding matrix. Potentiodynamic polarization curves confirmed that WM is cathode rather than BM in different heat treatment cycles. Moreover, it was found that heat treatment led to displacement of the BM corrosion potential to noble direction. Observations of corroded surfaces confirmed localized corrosion.     

ILSBMR: improved LSBMR (ILSBMR) method

The Least Significant Bit Matching Revisited (LSBMR) is among the most commonly used methods on image steganography, aiming to make only smaller changes in an image. While security is considered as one of the basic evaluation criteria for steganography techniques and notably, LSBMR can be easily recognized due to its well-known structure, it is important to find a way to help improve this approach so that it might cause less variation in the image and also increase security. To this end, the current paper deploys divided blocks of the original cover image and a selection of the best layout to embed secret message bits from each block into color images by using LSBMR. The simulation results indicate that this improved method makes small changes in the image and increases its security, compared to the LSBMR technique.     

Novel Brønsted acidic ionic liquids catalyzed one-pot reaction of highly green regioselective thiocyanation of N-containing aromatic and heteroaromatic compounds at room temperature

In this method, a novel Brønsted acidic ionic liquid silica-supported pyridinium sulfonic acid thiocyanate {SiO₂@[Pyridine-SO₃H]SCN} and sulfonic acid-functionalized pyridinium chloride {[PSA]Cl} were easily synthesized and characterized. In the first method, {SiO₂@[Pyridine-SO₃H]SCN as a novel and environmentally friendly catalyst with one acidic functional group and one thiocyanation agent group was ef?ciently used for the synthesis of aryl and heteroaryl thiocyanates via the condensation of anilines, indoles, pyrroles, and their derivatives in the presence of H₂O₂ as a green oxidant in EtOH:H₂O (1:1) at room temperature. In the second method, {[PSA]Cl} as a new ionic liquid and environmentally friendly catalyst with one acidic functional group was used for the simple and efficient synthesis of aryl and heteroaryl thiocyanates via the condensation of anilines, indoles, pyrroles, and their derivatives with NH₄SCN in the presence of H₂O₂ as a green oxidant in EtOH:H₂O (1:1) at room temperature. A simple experimental procedure, clean reaction profile, use of an inexpensive catalyst, and recyclability of the catalyst are some of the advantages of the procedure. Also, one of the advantages of the first method is the non-usage of NH₄SCN or KSCN in the reaction.     

Gossip-Based Computation of a Gaussian Mixture Model for Distributed Multimedia Indexing

This paper deals with pattern recognition in a distributed computing context of the peer-to-peer type, that should be more and more interesting for multimedia data indexing and retrieval. Our goal is estimating of class-conditional probability densities, that take the form of Gaussian mixture models (GMM). Originally, we propagate GMMs in a decentralized fashion (gossip) in a network, and aggregate GMMs from various sources, through a technique that only involves little computation and that makes parsimonious usage of the network resource, as model parameters rather than data are transmitted. The aggregation is based on iterative optimization of an approximation of a KL divergence allowing closed-form computation between mixture models. Experimental results demonstrate the scheme to the case of speaker recognition.     

Deletions of single extracellular loops affect pH sensitivity, but not voltage dependence, of the Escherichia coli porin OmpF

The molecular basis for the voltage and pH dependence of the Escherichia coli OmpF porin activity remains unknown. The L3 loop was previously shown not be involved in voltage dependence. Here we used seven OmpF mutants where single extracellular loops, except L3, were deleted one at a time. The proteins are expressed at levels comparable to wild-type and purified as trimers. Wild-type and mutant proteins were inserted into planar lipid bilayers for electrophysiological measurement of their activity. Current-voltage relationships show the typical porin channel closure at voltages greater than the critical voltage. Measurements of critical voltages for the seven deletion mutants showed no significant differences relative to wild-type, hence eliminating the role of single loops in voltage sensitivity. However, deletions of loops L1, L7 or L8 affected the tendency of channels to close at acidic pH. Wild-type channels close more readily at acidic pH and their open probability is decreased by approximately 60% at pH 4.0 relative to pH 7.0. For mutants lacking loop L1, L7 or L8, the channel open probability was found not to be significantly different at pH 4.0 than at pH 7.0. The other deletion mutants retained a pH sensitivity similar to the wild-type channel. Possible mechanistic scenarios for the voltage- and pH dependence of E.coli OmpF porin are discussed based on these results.     

An efficient technique for dairy wastewater treatment

The aim of this study was to consider the efficiency of the electro‐Fenton process for organic compound reduction in an industrial dairy effluent. Experiments were conducted to evaluate the effect of several parameters, such as reaction time, pH, H₂O₂/Fe²⁺ molar ratio and volume fraction of H₂O₂ to dairy wastewater (mL/L), on the process performance. The Taguchi technique was applied to investigate the optimum operating conditions. The optimum chemical oxygen demand removal (93.24%) was experimentally obtained at a pH value of 7.58, reaction time of 87.13, current density of 58.5, H₂O₂/Fe²⁺ molar ratio of 3.62 and volume fraction of H₂O₂ to dairy wastewater of 1.39 mL/L.     

Acute renal failure due to severe Landry-Guillain-Barré syndrome

BACKGROUND: Blood urea nitrogen (BUN) >60 mg/dl has been reported to occur commonly in patient's with severe Landry-Guillain-Barré syndrome. AIMS: To find out the cause for this high BUN we compared the renal function tests of 30 consecutive cases with severe Landry-Guillain-Barré syndrome to those of 30 controls. RESULTS: Acute renal failure occurred in seven patients with Landry-Guillain-Barré syndrome and none of the control group. Acute renal failure was found more in cases with Landry-Guillain-Barré syndrome compared to controls (P=0.0049). Six out of seven cases with Landry-Guillain-Barré syndrome and acute renal failure had dysautonomia and became oliguric while being in a hypotensive state. Of 30 patients with Landry-Guillain-Barré syndrome seven cases died. From eight patients with dysautonomia six cases who had acute renal failure died. The mortality rate was higher in cases with dysautonomia and acute renal failure (P = 0.0001 and 0.00001, respectively). Interestingly no glomerular disease was found. CONCLUSION: In conclusion acute renal failure can occur commonly in cases with severe Landry-Guillain-Barré syndrome particularly in those with dysautonomia, causing high mortality.     

UMOTS: an uncertainty-aware multi-objective genetic algorithm-based static task scheduling for heterogeneous embedded systems

Increasing manufacturing process variations due to aggressive technology scaling in addition to heterogeneity in design components are expected to cause serious challenges for future embedded system design steps including task scheduling. Process variation effects along with increased complexity in embedded applications result in design uncertainties, which in turn, reduce the accuracy and efficiency of traditional design approaches with deterministic values for the design component parameters. In this paper, a multi-objective task scheduling framework is proposed for embedded systems considering uncertainties in both hardware and software component parameters. The tasks which are modeled as a task graph are scheduled on a specific hardware platform consisting of processors and communication parts. Uncertainty is considered in both software (task parameters) and hardware (processor and communication parameters) of the embedded system. UMOTS takes advantages of a Monte-Carlo-based approach within a multi-objective genetic algorithm to handle the uncertainties in model parameters. The proposed approach finds the Pareto frontier, which is robust against uncertainties, in the objective space formed by performance, energy consumption, and reliability. The efficiency of UMOTS is investigated in the experimental results using real-application task graphs. In terms of Scheduling Length Ratio (SLR) and speedup, UMOTS provides 27.8% and 28.6% performance improvements in comparison to HSHD, one state-of-the-art task scheduling algorithm. Additionally, UMOTS, which is based on a multi-objective genetic optimization algorithms, finds robust Pareto frontier with 1%, 5% and 10% uncertainty in design indicators with respect to design limitations.