Effect of gasket of varying thickness on spark ignition engines

In the study of Toyota, In-line, 4 cylinders, spark ignition engine using gaskets of varying thicknesses (1.75mm, 3.5mm, 5.25mm, 7mm and 8.75mm) between the cylinder head and the engine block, the performance characteristics of the engine was investigated via the effect of engine speed on brake power, brake thermal efficiency, volumetric efficiency and exhaust temperature. To evaluate the performance characteristics for definite gasket (GK) thickness, the engine was operated between 200 – 4000 rpm, under steady state condition. The investigation reveals worsening engine performance with increasing gasket thickness though with improved volumetric efficiency for any given speed range.KEYWORDS: Brake thermal efficiency, volumetric efficiency, Exhaust temperatur

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

Corrosion inhibition of mild steel in 15 wt.% HCl by durum wheat

The toxicity of most commercial corrosion inhibitors and strict environmental legislations have required the development of environmentally-friendly, cheap and non-toxic inhibitors. The use of natural products, especially of plant origin as corrosion inhibitors has become an area of increasing research because plant extracts contain an incredibly rich source of natural chemical compounds which can be extracted by simple procedures at low-cost. Durum wheat was investigated in this work because functional groups were identified which suggested that it could be a promising potential inhibitor. The corrosion of mild steel in 15 wt.% HCl solution with and without Durum wheat was investigated and directly compared to results from two commercial corrosion inhibitors, propargyl alcohol and 2- mercaptobenzimidazole, under the same conditions, by comparing weight loss with and without inhibition. The durum wheat powder and adsorbed films were characterised by Fourier transform infrared spectroscopy (FTIR), and the exposed samples were characterised using SEM, EDS spectroscopy and surface profilometry. The effects of concentration, temperature (20-60°C) and immersion time (5-24 h) on the corrosion inhibition were investigated. Durum wheat was shown to be a successful green corrosion inhibitor with a room temperature inhibition efficiency of 97% (as compared to values of 99% and 97% for propargyl alcohol and 2 - mercapto benzimidazole respectively) and at a lower cost per l L of corrosive solution. However, at the severe corrosive conditions chosen for this research, the inhibition performance of both durum wheat and 2- mercaptobenzimidazole was influenced by time and temperature, and the durum wheat corrosion inhibition was reduced to 78% after 24 hours at 60°C, compared to 88% for 2- mercaptobenzimidazole. All the inhibitors investigated obeyed Langmuir adsorption isotherm

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

Corrosion inhibition of mild steel in 15 wt.% HCl by durum wheat

The toxicity of most commercial corrosion inhibitors and strict environmental legislations have required the development of environmentally-friendly, cheap and non-toxic inhibitors. The use of natural products, especially of plant origin as corrosion inhibitors has become an area of increasing research because plant extracts contain an incredibly rich source of natural chemical compounds which can be extracted by simple procedures at low-cost. Durum wheat was investigated in this work because functional groups were identified which suggested that it could be a promising potential inhibitor. The corrosion of mild steel in 15 wt.% HCl solution with and without Durum wheat was investigated and directly compared to results from two commercial corrosion inhibitors, propargyl alcohol and 2- mercaptobenzimidazole, under the same conditions, by comparing weight loss with and without inhibition. The durum wheat powder and adsorbed films were characterised by Fourier transform infrared spectroscopy (FTIR), and the exposed samples were characterised using SEM, EDS spectroscopy and surface profilometry. The effects of concentration, temperature (20-60°C) and immersion time (5-24 h) on the corrosion inhibition were investigated. Durum wheat was shown to be a successful green corrosion inhibitor with a room temperature inhibition efficiency of 97% (as compared to values of 99% and 97% for propargyl alcohol and 2 - mercapto benzimidazole respectively) and at a lower cost per l L of corrosive solution. However, at the severe corrosive conditions chosen for this research, the inhibition performance of both durum wheat and 2- mercaptobenzimidazole was influenced by time and temperature, and the durum wheat corrosion inhibition was reduced to 78% after 24 hours at 60°C, compared to 88% for 2- mercaptobenzimidazole. All the inhibitors investigated obeyed Langmuir adsorption isotherm

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

New putative antimicrobial candidates: In silico design of fish-derived antibacterial peptide-motifs

Antimicrobial resistance remains a great threat to global health. In response to the World Health Organizations’ global call for action, nature has been explored for novel and safe antimicrobial candidates. To date, fish have gained recognition as potential source of safe, broad spectrum and effective antimicrobial therapeutics. The use of computational methods to design antimicrobial candidates of industrial application has however, been lagging behind. To fill the gap and contribute to the current fish-derived antimicrobial peptide repertoire, this study used Support Vector Machines algorithm to fish out fish-antimicrobial peptide-motif candidates encrypted in 127 peptides submitted at the Antimicrobial Peptide Database (APD3), steered by their physico-chemical characteristics (i.e., positive net charge, hydrophobicity, stability, molecular weight and sequence length). The best two novel antimicrobial peptide-motifs (A15_B, A15_E) with the lowest instability index (−28.25, −22.49, respectively) and highest isoelectric point (pI) index (10.48 for each) were selected for further analysis. Their 3D structures were predicted using I-TASSER and PEP-FOLD servers while ProSA, PROCHECK, and ANOLEA were used to validate them. The models predicted by I-TASSER were found to be better than those predicted by PEP-FOLD upon validation. Two I-TASSER models with the lowest c-score of −0.10 and −0.30 for A15_B and A15_E peptide-motifs, respectively, were selected for docking against known bacterial-antimicrobial target-proteins retrieved from protein databank (PDB). Carbapenam-3-carboxylate synthase (PDB ID; 4oj8) yielded the lowest docking energy (−8.80 and −7.80 Kcal/mol) against motif A15_B and A15_E, respectively, using AutoDock VINA. Further, in addition to Carbapenam-3-carboxylate synthase, these peptides (A15_B and A15_E) were found to as well bind to membrane protein (PDB ID: 1by3) and Carbapenem synthetase (PDB: 1q15) when ClusPro and HPEPDOCK tools were used. The membrane protein yielded docking energy scores (DES): −290.094, −270.751; coefficient weight (CW): −763.6, 763.3 for A15_B and A15_E) whereas, Carbapenem synthetase (PDB: 1q15) had a DES of −236.802, −262.75 and a CW of −819.7, −829.7 for peptides A15_B and A15_E, respectively. Motif A15_B of amino acid positions 2–19 in Pleurocidin exhibited the strongest in silico antimicrobial potentials. This segment could be a good biological candidate of great application in pharmaceutical industries as an antimicrobial drug candidate

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

The past 2 years, during which waves of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants swept the globe, have starkly highlighted health disparities across nations. Tegally et al. show how the coordinated efforts of talented African scientists have in a short time made great contributions to pandemic surveillance and data gathering. Their efforts and initiatives have provided early warning that has likely benefited wealthier countries more than their own. Genomic surveillance identified the emergence of the highly transmissible Beta and Omicron variants and now the appearance of Omicron sublineages in Africa. However, it is imperative that technology transfer for diagnostics and vaccines, as well the logistic wherewithal to produce and deploy them, match the data-gathering effort