Evaluation of inulin and aloe vera as green corrosion inhibitors for mild steel in 15% HCl

REACH legislation and PARCOM recommendations are driving research in environmental friendly alternatives to the highly toxic compounds currently used as corrosion inhibitors. Here two candidate plant extract green corrosion inhibitors are evaluated by direct comparison with commercially used corrosion inhibitors propargyl alcohol and 2-mercaptobenzimidazole. The two candidate green corrosion inhibitors are: 1. commercially available powdered inulin, extracted from Jerusalem artichoke; 2. aloe vera gel extracted directly from the plants. Immersion tests and weight loss measurements are used to determine the behaviour and inhibition efficiency as a function of concentration and temperatures of 20 ⁰C to 60 ⁰C for mild steel in 15% HCl. Results show that inulin and aloe vera act as corrosion inhibitors over the range of conditions used, the optimal concentration for both was 10%, compared to 0.4% for the commercial corrosion inhibitors. Inhibition efficiencies of up to 86% and 84% were observed for inulin and aloe vera respectively, compared to values of over 95% for the commercial corrosion inhibitors. There is some variation of behaviour for inulin and aloe vera with time and temperature

Fatigue Performance Enhancement of Selectively Laser Melted Aluminum Alloy by Heat Treatment

We measured the stress-strain behaviour and fatigue performance of the aluminium alloy Al-Si10-Mg manufactured by selective laser melting (SLM). This process, specifically the rapid cooling of the metal from its molten state, results in a fine microstructure, generally providing high hardness but poor ductility. We used a heat treatment to alter the microstructure of the material from its as-built state. This significantly improved the ductility and fatigue performance. The elongation at break for the heat treated material was nearly three times greater than that observed for the as-built material, and the fatigue strength at 106 cycles was around 1.6 times as high. Combined with the design freedoms of additive manufacture, this development increases the suitability of lightweight SLM parts for use in the aerospace and automotive sectors, where good fatigue performance is essential.Mechanical Engineerin

Green corrosion inhibitors: amino acids and plant extracts

Corrosion inhibitors are chemicals that are used in many industries to control corro-sion. As they are injected into process streams they have to be continually replen-ished in order to maintain protection. Many chemicals used are environmentally un-friendly highly toxic compounds including chromates and arsenic compounds. REACH legislation and PARCOM recommendations as well as general environmen-tal concerns are driving an effort to find acceptable alternatives to conventional cor-rosion inhibitors. Promising initial work in the open literature has already identified several alternative green corrosion inhibitors, including plant extracts that have po-tential to be used as more environmentally acceptable corrosion inhibitors. However, to date a lot of the work has been done on a trial and error basis with little considera-tion of the mechanisms of inhibition or any detailed characterisation of the inhibited surface. Three candidate types of environmentally friendly corrosion inhibitors are identified as worth of further consideration: the amino acids histidine and tryptophan, aloe vera plant extract and plants with high inulin contents. Initial results on the effectiveness of the amino acids in protecting mild steel in an acidic environment are determined via immersion tests and weight loss measurements. The evolution of the inhibition film is studied using electrochemical measurements. Experiments are carried out at tem-peratures of 20 ⁰C to 60 ⁰C. Results are compared with those from the widely used corrosion inhibitor propargyl alcohol. The amino acids show some effectiveness as corrosion inhibitors in the environment used however further work on other candidate green corrosion inhibitors, including full lifecycle costing, is required to fully assess their potential. 1 Introductio

Finite covers of random 3-manifolds

A 3-manifold is Haken if it contains a topologically essential surface. The Virtual Haken Conjecture posits that every irreducible 3-manifold with infinite fundamental group has a finite cover which is Haken. In this paper, we study random 3-manifolds and their finite covers in an attempt to shed light on this difficult question. In particular, we consider random Heegaard splittings by gluing two handlebodies by the result of a random walk in the mapping class group of a surface. For this model of random 3-manifold, we are able to compute the probabilities that the resulting manifolds have finite covers of particular kinds. Our results contrast with the analogous probabilities for groups coming from random balanced presentations, giving quantitative theorems to the effect that 3-manifold groups have many more finite quotients than random groups. The next natural question is whether these covers have positive betti number. For abelian covers of a fixed type over 3-manifolds of Heegaard genus 2, we show that the probability of positive betti number is 0. In fact, many of these questions boil down to questions about the mapping class group. We are lead to consider the action of mapping class group of a surface S on the set of quotients pi_1(S) -> Q. If Q is a simple group, we show that if the genus of S is large, then this action is very mixing. In particular, the action factors through the alternating group of each orbit. This is analogous to Goldman's theorem that the action of the mapping class group on the SU(2) character variety is ergodic.Comment: 60 pages; v2: minor changes. v3: minor changes; final versio

Indentation creep and anisotropy in magnesium oxide and gemanium

SIGLEAvailable from British Library Document Supply Centre- DSC:D171303 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Green corrosion inhibitors: amino acids and plant extracts

Corrosion inhibitors are chemicals that are used in many industries to control corro-sion. As they are injected into process streams they have to be continually replen-ished in order to maintain protection. Many chemicals used are environmentally un-friendly highly toxic compounds including chromates and arsenic compounds. REACH legislation and PARCOM recommendations as well as general environmen-tal concerns are driving an effort to find acceptable alternatives to conventional cor-rosion inhibitors. Promising initial work in the open literature has already identified several alternative green corrosion inhibitors, including plant extracts that have po-tential to be used as more environmentally acceptable corrosion inhibitors. However, to date a lot of the work has been done on a trial and error basis with little considera-tion of the mechanisms of inhibition or any detailed characterisation of the inhibited surface. Three candidate types of environmentally friendly corrosion inhibitors are identified as worth of further consideration: the amino acids histidine and tryptophan, aloe vera plant extract and plants with high inulin contents. Initial results on the effectiveness of the amino acids in protecting mild steel in an acidic environment are determined via immersion tests and weight loss measurements. The evolution of the inhibition film is studied using electrochemical measurements. Experiments are carried out at tem-peratures of 20 ⁰C to 60 ⁰C. Results are compared with those from the widely used corrosion inhibitor propargyl alcohol. The amino acids show some effectiveness as corrosion inhibitors in the environment used however further work on other candidate green corrosion inhibitors, including full lifecycle costing, is required to fully assess their potential. 1 Introductio

Laboratory evaluation of a vibrating orifice monodisperse aerosol generator

SIGLEAvailable from British Library Lending Division - LD:9091.9F(AEEW-R--1901) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Evolution of pH in a radwaste repository Internal reactions between concrete consituents

10.00; DOE/RW--89.025 pt. 2Available from British Library Document Supply Centre- DSC:9091.9F(AERE-R--12939) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Evolution of pH in a radwaste repository Experimental simulation of cement leaching

8.00; DOE/RW--89.025 pt. 1Available from British Library Document Supply Centre- DSC:9091.9F(AERE-R--12594) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo