Determination of susceptibility to intergranular corrosion of stainless steels type X5CrNi18-10 in field

In this paper, the DL EPR method (electrochemical potentiokinetic reactivation with double loop) was modified and used to study the susceptibility to intergranular corrosion and stress corrosion cracking of a stainless steel type X5CrNi18-10. The tests were performed in a special electrochemical cell, with the electrolyte in the gel form. Modified DL EPR method is characterized by simple and high accuracy measurements as well as repeatability of the test results. The indicator of susceptibility to intergranular corrosion (Qr/Qp)GBA obtained by modified DL EPR method is in a very good agreement with the same indicator obtained by standard DL EPR method. The modified DL EPR method is quantitative and highly selective method. Small differences in the susceptibility of the stainless steel type CrNi18-10 to intergranular corrosion and stress corrosion cracking can be determined. Test results can be obtained in a short time. The cost of tests performed by modified DL EPR method is much lower than the cost of tests by conventional chemical methods. Modified DL EPR method can be applied in the field on the stainless steels constructions

Natural peptides with antioxidant activity from Atlantic cod and Atlantic salmon residual material

Summary. Water-soluble peptides/proteins with molecular weight below 10 kDa were isolated from residual material of cod (liver, skin, and cod mix i.e. skin, frames, and viscera), and salmon (skin, and salmon mix i.e. skin, frames, and viscera) by cut-off filtration. Peptide motifs with reported bioactivity were identified in all samples by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) (Orbitrap), bioinformatics, and database search. Peptides with potential type 2 diabetes, cardio system, immunomodulation, prolyl endopeptidase (PEP), and antioxidant activity were detected. The potential antioxidant activity in the samples was confirmed by two antioxidant assays, namely hydroxyl radical scavenging activity (HRSA), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation decolorization assay. In these assays the salmon samples were found to possess higher antioxidant activity than the cod samples. All samples except the cod skin were found to have higher antioxidant activity than alanine-histidine (AH), a dipeptide with known antioxidant activity. Industrial relevance. Residual material from fisheries and aquaculture makes up large quantities of material. Although previously regarded as waste this material has valuable components that are of interest for the biotech industry. The fractionation process utilized in this work offers the possibility for simple isolation of interesting peptides with antioxidant activity. This method should be of interest for the food industry and biotech industry for product development

Grounding of Human Environments and Activities for Autonomous Robots

With the recent proliferation of robotic applications in domestic and industrial scenarios, it is vital for robots to continually learn about their environments and about the humans they share their environments with. In this paper, we present a framework for autonomous, unsupervised learning from various sensory sources of useful human ‘concepts’; including colours, people names, usable objects and simple activities. This is achieved by integrating state-of-the-art object segmentation, pose estimation, activity analysis and language grounding into a continual learning framework. Learned concepts are grounded to natural language if commentary is available, allowing the robot to communicate in a human-understandable way. We show, using a challenging, real-world dataset of human activities, that our framework is able to extract useful concepts, ground natural language descriptions to them, and, as a proof-of-concept, to generate simple sentences from templates to describe people and activities

Can Polarity-Inverted Surfactants Self-Assemble in Nonpolar Solvents

We investigate the self-assembly process of a surfactant with inverted polarity in water and cyclohexane using both all-atom and coarse grained hybrid particle-field molecular dynamics simulations. Unlike conventional surfactants, the molecule under study, proposed in a recent experiment, is formed by a rigid and compact hydrophobic adamantane moiety, and a long and floppy triethylene glycol tail. In water, we report the formation of stable inverted micelles with the adamantane heads grouping together into a hydrophobic core, and the tails forming hydrogen bonds with water. By contrast, microsecond simulations do not provide evidence of stable micelle formation in cyclohexane. Validating the computational results by comparison with experimental diffusion constant and small-angle X-ray scattering intensity, we show that at laboratory thermodynamic conditions the mixture resides in the supercritical region of the phase diagram, where aggregated and free surfactant states co-exist in solution. Our simulations also provide indications about how to escape this region, to produce thermodynamically stable micellar aggregates.Comment: 14 pages, 10 Figures, accepted for publication (2020

Wear resistance improvement of thermal plant fan mill impact plates based on numerical flow simulation

Numerical simulation of 3D multiphase flow is performed to determine the velocity field in the fan mill. The mixture model of the Euler-Euler approach is used. Recirculating gas is a primary phase that carries granular phases including the coal powder and sand. The latter causes heavy wear of mill impact plates. The optimal form of hardfacing geometry and technology has an impact both on velocity magnitude and direction of flow in such a way as to reduce plate wear. This paper presents results of surface modification (based on numerical simulation), implemented on impact plates of the fan mill in the Kostolac B power plant in Serbia. Fishbone hardfacing is made in order to increase the lifetime of impact plates and extend the period between overhauls of fan mills. The experimental tests of fishbone surfacing plates, in exploitation conditions, show that the applied modification, hardfacing technologies and coating materials, give expected results. The application of this hardfacing in the form of a fishbone is simpler, faster and more economical compared to complete overlaying and honeycomb impact plate surfacing. The relative weight loss of base plate after an 1440-hour period of exploitation is 8%, while the weight losses for the hard-faced plate is below 7%

Turbulence recognition in free convective flow by thermal-video post-processing in the case of a thermal power plant mill

This paper presents a study of a free convection flow around the walls of a ventilation mill of the Thermal Power Plant "Kostolac B", Kostolac, Serbia. A combined method consists of thermography and software post-processing, PATS. The PATS is specially developed for recognition of turbulence zones by the custom processing of large input data sets from thermal videos. The calculations determine maximum temperature fluctuation i.e. peak-to-peak fluctuation at every spot during the recording time. Three thermal videos of the walls were analyzed. Maximum temperature fluctuation occurred in the zones close to the obstacles, which are thus recognized as one of the main sources of turbulence. Besides, PATS has recognized fine camera oscillations and mechanical movements of a flexible material near the dozer wall. The detected zones of turbulence correspond to the previous studies and to the theory. The method shows good potential in the field of free convective flow research through the improvement of testing efficiency and cost savings. State-of-the-art thermograph cameras and updated software are recommended

An Analysis of the Roles of the Practitioners in the Implementation of the Environmental Impact Assessment in South Africa

Various national, domestic, and international legal instruments provide for the significance of ensuring that, prior, during, and after any proposed or completed project, a thorough EIA must be carried out, to establish the extent of the impact and the effect of such a developmental project would have on the environment. To accomplish this, the role of Environmental Assessment Practitioners (EAP) became more imperative. This paper looks at the various roles of these practitioners, their professional advice based on their assessments, whether a project should get the go-ahead to continue or not, stating and indicating the imminent risks to the environment, how to mitigate them, and if need be how to abate the project

Korozioni potencijal nerđajućeg čelika 304 u sumpornoj kiselini

The potentiodynamic study of the electrochemical behavior of austenitic 304 stainless steel in deaerated aqueous sulfuric acid of pH 1 revealed that the steel achieved a stable corrosion potential of ca. - 0.350 V (SCE) independent of whether the electrode had previously been cathodically "activated" or anodically passivated. It was also shown that the experimentally observed anodic peak was not the usually obtained anodic passivation peak, as is the case with a number of metal, but an artifact due to the anodic oxidation of hydrogen absorbed during the previously employed cathodic polarization and hydrogen evolution, intended to activate the initially passive surface, or even hydrogen absorbed on the open circuit potential. It was shown that this potential establishes and electrochemical corrosion potential of the Wagner-Traud type due to the evolution of cathodic hydrogen on a passivated steel surface and anodic metal dissolution through the passive layer. It was impossible to activate 304 stainless steel in sulfuric acid of pH 1 by cathodic polarization, and the usually observed anodic peak obtained under these conditions should not be considered as an active metal dissolution process and a passivation anodic peak, but rather as an artifact due to the electrochemical oxidation of the in the steel absorbed hydrogen.Potenciodinamička ispitivanja elektrohemijskog ponašanja nerđajućeg čelika 304 u deaeriranoj sumpornoj kiselini sa pH 1 pokazala su da se na čeliku uspostavlja stabilan korozioni potencijal od - 0,350 V(ZKE) nezavisno od toga da li je elektroda prethodno katodno tretirana radi "aktivacije", ili je površina bila pasivirana. Pokazano je, takođe, da eksperimentalno dobijeni anodni maksimum na potenciodinamičkoj krivi pozitivnije od korozionog potencijala nije anodni pasivacioni maksimum koji se obično dobija pri anodnoj polarizaciji većeg broja metala u sličnim uslovima, već eksperimentalni artefakt koji nastaje zbog anodne oksidacije vodonika apsorbovanog unutar čelika tokom katodnog "aktiviranja" ili čak i pri dužem držanju na korozionom potencijalu. Pokazano je da je spontano formirani potencijal otvorenog kola zapravo korozioni potencijal koji nastaje kao mešoviti potencijal Vagner-Traudovog tipa suprotnim delovawem katodne reakcije izdvajanja vodonika na pasivnom sloju i anodnog rastvaranja čelika kroz pasivni sloj. Nije bilo mogućno katodnom "aktivacijom" i dugotrajnijom katodnom polarizacijom do značajno negativnih potencijala i vrlo velikih katodnih struja da se pasivni sloj ukloni i postigne aktivno elektrohemijsko rastvaranje metala bez prisustva pasivnog sloja, tj. slobodna metalna površina. Stoga, često eksperimentalno konstatovan anodni maksimum na ovakvim čelicima ne treba da se interpretira kao anodno rastvaranje sa pasivacionim maksimumom, već kao posledica anodne oksidacije apsorbovanog vodonika u pasivnom čeliku, a koji se pod ovim uslovima ne može elektrohemijski aktivirati, odn. depasivirati