Ahmad Fuad Ab Ghani, Mohamad Kamarul Anwar Sahar, Muhammad Ridzuan Husyairi Azmi, Nurul Izzati Medon, Muhammad Syazwan Samsuri, Muhammad Syurabil Abdani
There are several types of grating, such as platform, bridge decks and filters. In design process, there
are several important terms that have to be prioritised; engineering design, strength to weight ratio, cost,
maintainability, reparability etcetera. Advanced materials, such as composite materials offer great
strength to weight ratio and high mechanical properties for grating fabrication. Furthermore the
reparability and maintenance problems could be solved as it is anti corrosion and the long service life
attribute of composite makes it a great design material for replacement of conventional steel or
aluminium. Bio composites, such as bamboo and coir fiber yield advantage in terms of less cost and
abundance availability compared to commercial unidirectional composite materials, such as glass fiber
reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP) which is considerably
expensive yet possess higher mechanical properties. This papers presents a conceptual design of
grating design utilizing bamboo composite as material. Pugh method has been chosen as design criteria
selection matrix in finalizing the design of industrial grating for scaffolding (Pugh, 1991).
This article presents a Wall Climbing Robot (WCR) that able to move on ferromagnetic vertical surface to carry out visual inspection process. Visual inspection process is important in the industry to check the condition of storage tank, surface of building, piping or equipment thus can prevents structures collapsing or explosion which would bring a huge loss to the company. Moreover, most of the structures nowadays is expose under the sun and rain, corrosion and cracks could easily occur on the surface after exposing under sunlight and rain a long period of time. Therefore the periodic visual inspection process need to be carry out to detect the damaged occur on the surface of the structure and take action at the fastest time to ensure the safety of the structures and extend the lifespan of the structures. With the well maintenance to the structures, the condition of the structures is monitored and the lifespan is longer. The risk of collapse of the building is decrease by a large margin. Normally, the periodic visual inspection process is performed by operator. Sometime the temporary scaffolding is needed to reach the higher place to carry out the inspection. However, this method create a hazardous environment to the operator and cause the safety of the operator threatened. Therefore, the proposed WCR could help operator to work at the hazardous environment. The permanent magnet is used to provide adhesion for WCR, thus WCR able to move on vertical ferromagnetic surface. The WCR is controlled by operator via wireless remote to reach the higher place or the hazardous environment. The operator then can stream the on the real time images via web browser which connected to the same network with the WCR. Hence, the condition of the surface can be observed.
Treated Rhizopora mucronata tannin (RMT) as a corrosion inhibitor for carbon steel and copper in oil and gas facilities was investigated. Corrosion rate of carbon-steel and copper in 3wt% NaCl solution by RMT was studied using chemical (weight loss method) and spectroscopic (FTIR) techniques at various temperatures in the ranges of 26-90°C. The weight loss data was compared to the electrochemical by the application of Faraday's law for the conversion of corrosion rate data from one system to another. The inhibitive efficiency of RMT was compared with commercial inhibitor sodium benzotriazole (BTA-S). The best concentration of RMT was 20% (w/v), increase in concentration of RMT decreased the corrosion rate and increased the inhibitive efficiency. Increase in temperature increased the corrosion rate and decreased the inhibitive efficiency but, the rate of corrosion was mild with RMT. The FTIR result shows the presence of hydroxyl group, aromatic group, esters and the substituted benzene group indicating the purity of the tannin. The trend of RMT was similar to that of BTA-S, but its inhibitive efficiency for carbon-steel was poor (6%) compared to RMT (59%). BTA-S was efficient for copper (76%) compared to RMT (74%) at 40% (w/v) and 20% (w/v) concentration respectively. RMT was efficient even at low concentration therefore, the use of RMT as a cost effective and environmentally friendly corrosion inhibiting agent for carbon steel and copper is herein proposed.
The aluminium-silicon (Al-Si) based on Metal Matrix Composites (MMCs) is widely used in lightweight
constructions and transport applications requiring a combination of high strength and ductility. A grain
refinement plays a crucial role in improving characteristics and properties of Al alloys. In this investigation,
titanium diboride (TiB2) and scandium (Sc) inoculants were added to the Al-Si alloys for grain refinement of
an alloy. In this investigation, the corrosion resistance rate of Al-Si cast alloy reinforced by TiB2 and Sc were
measured by potentiostat (AUTOLAB) instrument. The aim of this research is to investigate the corrosion
rate for Al-Si-TiB2-Sc composites that immersed in different concentration of acidic solutions. Besides, the
immersion time of acidic solutions also was investigated. All the samples were prepared accordingly for
ASTM standard by the composition of 6.0 wt% TiB2 and 0.6wt% Sc. All the samples undergo cold mounting
technique for easy handling on corrosion tests. Then the samples were immersed in two different
concentrations acidic medium solutions, which were 0.1.and 1.0 M hydrochloric acids (HCl). The corrosion
rate also was investigated for immersion samples of 1.0 M HCl for 21 days. From the results obtained, added
TiB2 and Sc onto Al-Si alloy gave the better properties in corrosion resistance. Corrosion rates to reduce when
the samples were immersed in a lower concentration of acidic medium, 0.1 HCl. However, there are some
significant on the result but it still following the corrosion rates trend. Thus, improvements to reinforcement
content need to be done in further research to cover the lack of this corrosion rates trend.
Corrosion is a natural deterioration process that destructs metal surface. Metal of highly
protected by passivation layer such as Stainless Steel 316L also undergoes pitting corrosion
when continuously exposed to aggressive environment. To overcome this phenomenon, application
of epoxy based coating with addition of zinc oxide- poly (3,4-ethylenedioxythiophene)
doped with poly (styrene sulphonate) hybrid nanocomposite additive was introduced as
paint/metal surface coating. The compatibility between these two materials as additive
was studied by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD),
Field Emission Scanning Electron Microscopy/Energy-Dispersive X-ray spectroscopy (FESEM/EDX)
and Transmission Electron Microscopy (TEM) analysis. The effect of nanocomposite
wt.% in epoxy based coating with immersion duration in real environment on corrosion
protection performance was analyzed through potentiodynamic polarization analysis. The
main finding showed that addition of hybrid nanocomposite had increased corrosion protection
yet enhanced corrosion process when excess additives was loaded into epoxy coating.
Addition of 2 wt.% ZnO-PEDOT:PSS was found significantly provided optimum corrosion
protection to stainless steel 316L as the corrosion rate for 0 day, 15 days and 30 days of
immersion duration is 0.0022 mm/yr, 0.0004 mm/yr and 0.0015 mm/yr; respectively.
Sterilisation is an essential step in the reprocessing of reusable dental instruments including burs that have become contaminated, or potentially contaminated. Transmission of disease or infection may happen as an effect of improper sterilisation of the reused instruments. Dental burs are one of the essential tools in any conservative dental procedures, which undergo multiple sterilisation cycles before being discarded. However, repeated sterilisation process is associated with the reduction in cutting efficiency of a bur that is potentially due to corrosion. Thus, this study aims to compare the effect of two sterilisation methods on cutting efficiency of a diamond bur that is commonly used in dental procedures. Methods: 30 fissure diamond burs were randomly divided into three sterilisation groups: Group A (dry heat), B (steam under pressure) and C (control). Each bur was used to cut teeth for 45 seconds for ten cycles. Between cuts, the burs underwent sterilisation based on their sterilisation groups. Amount of cutting weight was measured after each cut. Results: This study shows that no significant difference (p>0.05) in the cutting efficiency of the burs following sterilisation of Groups A and B. However, there is a significant mean difference (p
A study has been presented on the effects of intrinsic mechanical parameters, such as surface stress, surface elastic modulus, surface porosity, permeability and grain size on the corrosion failure of nanocomposite coatings. A set of mechano-electrochemical equations was developed by combining the popular Butler-Volmer and Duhem expressions to analyze the direct influence of mechanical parameters on the electrochemical reactions in nanocomposite coatings. Nanocomposite coatings of Ni with Al₂O₃, SiC, ZrO₂ and Graphene nanoparticles were studied as examples. The predictions showed that the corrosion rate of the nanocoatings increased with increasing grain size due to increase in surface stress, surface porosity and permeability of nanocoatings. A detailed experimental study was performed in which the nanocomposite coatings were subjected to an accelerated corrosion testing. The experimental results helped to develop and validate the equations by qualitative comparison between the experimental and predicted results showing good agreement between the two.
Microbiologically influenced corrosion (MIC) is among the common corrosion types for buried and deep-water pipelines that result in costly repair and pipeline failure. Sulfate-reducing bacteria (SRB) are commonly known as the culprit of MIC. The aim of this work is to investigate the performance of combination of ultrasound (US) irradiation and ultraviolet (UV) radiation (known as Hybrid soliwave technique, HyST) at pilot scale to inactivate SRB. The influence of different reaction times with respect to US irradiation and UV radiation and synergistic effect toward SRB consortium was tested and discussed. In this research, the effect of HyST treatment toward SRB extermination and corrosion studies of carbon steel coupon upon SRB activity before and after the treatment were performed using weight loss method. The carbon steel coupons immersed in SRB sample were exposed to HyST treatment at different time of exposure. Additionally, Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy were used to investigate the corrosion morphology in verifying the end product of SRB activity and corrosion formation after treatment. Results have shown that the US irradiation treatment gives a synergistic effect when combined with UV radiation in mitigating the SRB consortium.
Corrosion prevention in biomaterials has become crucial particularly to overcome inflammation and allergic reactions caused by the biomaterials' implants towards the human body. When these metal implants contacted with fluidic environments such as bloodstream and tissue of the body, most of them became mutually highly antagonistic and subsequently promotes corrosion. Biocompatible implants are typically made up of metallic, ceramic, composite and polymers. The present paper specifically focuses on biocompatible metals which favorably used as implants such as 316L stainless steel, cobalt-chromium-molybdenum, pure titanium and titanium-based alloys. This article also takes a close look at the effect of corrosion towards the implant and human body and the mechanism to improve it. Due to this corrosion delinquent, several surface modification techniques have been used to improve the corrosion behavior of biocompatible metals such as deposition of the coating, development of passivation oxide layer and ion beam surface modification. Apart from that, surface texturing methods such as plasma spraying, chemical etching, blasting, electropolishing, and laser treatment which used to improve corrosion behavior are also discussed in detail. Introduction of surface modifications to biocompatible metals is considered as a "best solution" so far to enhanced corrosion resistance performance; besides achieving superior biocompatibility and promoting osseointegration of biocompatible metals and alloys.
A corrosive environment leaves in-service conductive structures prone to subsurface corrosion which poses a severe threat to the structural integrity. It is indispensable to detect and quantitatively evaluate subsurface corrosion via non-destructive evaluation techniques. Although the gradient-field pulsed eddy current technique (GPEC) has been found to be superior in the evaluation of corrosion in conductors, it suffers from a technical drawback resulting from the non-uniform field excited by the conventional pancake coil. In light of this, a new GPEC probe with uniform field excitation for the imaging of subsurface corrosion is proposed in this paper. The excited uniform field makes the GPEC signal correspond only to the field perturbation due to the presence of subsurface corrosion, which benefits the corrosion profiling and sizing. A 3D analytical model of GPEC is established to analyze the characteristics of the uniform field induced within a conductor. Following this, experiments regarding the imaging of subsurface corrosion via GPEC have been carried out. It has been found from the results that the proposed GPEC probe with uniform field excitation not only applies to the imaging of subsurface corrosion in conductive structures, but provides high-sensitivity imaging results regarding the corrosion profile and opening size.
The protection of concrete structures against corrosion in marine environments has always been a challenge due to the presence of a saline solution-A natural corrosive agent to the concrete paste and steel reinforcements. The concentration of salt is a key parameter influencing the rate of corrosion. In this paper, we propose an optical fiber-based salinity sensor based on bundled multimode plastic optical fiber (POF) as a sensor probe and a concave mirror as a reflector in conjunction with an intensity modulation technique. A refractive index (RI) sensing approach is analytically investigated and the findings are in agreement with the experimental results. A maximum sensitivity of 14,847.486/RIU can be achieved at RI = 1.3525. The proposed technique is suitable for in situ measurement and monitoring of salinity in liquid.
In this work, binary Zn-0.5Al and ternary Zn-0.5Al-xMg alloys with various Mg contents were investigated as biodegradable materials for implant applications. Compared with Zn-0.5Al (single phase), Zn-0.5Al-xMg alloys consisted of the α-Zn and Mg2(Zn, Al)11 with a fine lamellar structure. The results also revealed that ternary Zn-Al-Mg alloys presented higher micro-hardness value, tensile strength and corrosion resistance compared to the binary Zn-Al alloy. In addition, the tensile strength and corrosion resistance increased with increasing the Mg content in ternary alloys. The immersion tests also indicated that the corrosion rates in the following order Zn-0.5Al-0.5Mg
A new technique was accepted to fill the porosity of Al coating applied by arc thermal spray process to enhance corrosion resistance performance in artificial ocean water. The porosity is the inherent property of arc thermal spray coating process. In this study, applied coating was treated with different concentrations of ammonium phosphate mono basic (NH4H2PO4: AP) solution thereafter dried at room temperature and kept in humidity chamber for 7d to deposit uniform film. The corrosion resistance of Al coating and treated samples have been evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic techniques with exposure periods in artificial ocean water. Electrochemical techniques, X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM) and field emission-scanning electron microscopy (FE-SEM) indicated that phosphate ion would have been retarding corrosion of Al coating effectively. The formation of AHP (Ammonium Aluminum Hydrogen Phosphate Hydrate: NH4)3Al5H6(PO4)8.18H2O) on Al coating surface after treatment with AP is nano sized, crystalline and uniformly deposited but after exposure them in artificial ocean water, they form AHPH (Aluminum hydroxide phosphate hydrate Al3(PO4)2(OH)3(H2O)5) that is very protective, adherent, uniform and plate like morphology of corrosion products. The AHPH is sparingly soluble and adherent to surface and imparted improved corrosion resistance.
Baram Delta Operation had been producing oil and gas since 1960's and serious pipelines failure was reported in the year of 2005. The final investigation has concluded that one of the species of bacteria that has been identified to cause microbiologically influenced corrosion, specifically known as sulfate reducing bacteria (SRB) was found to be one of the potential contributing factors to the incidents. This work investigates the potential use of ultraviolet (UV) radiation to inhibit the SRB consortium that was cultivated from the crude oil in one of the main trunk lines at Baram Delta Operation, Sarawak, Malaysia. The impact of UV exposure to bio-corrosion conditions on carbon steel coupon in certain samples for 28 days was discussed in this study. The samples were exposed to UV radiation based on variations of parameters, namely: time of UV exposure; and power of UV lamp. The significant changes on the amount of turbidity reading and metal loss of the steel coupon were recorded before and after experiment. The results showed that SRB growth has reduced rapidly for almost 90% after the UV exposure for both parameters as compared to the abiotic samples. Metal loss values were also decreased in certain exposure condition. Additionally, field emission scanning electron microscopy (FESEM) coupled with energy dispersive spectroscopy (EDS) was performed to observe the biofilm layer formed on the metal surface after its exposure to SRB. The evidence suggested that the efficiency of UV treatment against SRB growth could be influenced by the particular factors studied
Concrete durability determines service life of structures. It can though, be weakened by aggressive environmental conditions. For instance, bio-corrosion process is due to the presence and activity of microorganisms which produce sulphuric acid to form sulphate deterioration of concrete materials. The problems related to durability and repair systems are due to lack of suitable concrete materials. The use bacteria for concrete repairing and plugging of pores and cracking in concrete has been recently explored. Previous studies had proved the possibility of using specific bacteria via bio concrete as a sustainable method for improving concrete properties. Thus, lack of information on the application of bio concrete exposed to extreme condition was the motivation for this research.
Two imines of different molecular sizes namely 3-(phenylimino) indolin-2-one (PII) and 3,3- (1,4-phenylenebis (azan-1-yl-1-ylidene) diindolin-2-one (PDI) were investigated for their corrosion inhibition on mild steel in 1 M HCl solution using electrochemical impedance spectroscopy (EIS). The bigger molecule PDI containing double the amount of isatin moiety exhibited higher inhibition efficiency of 87.3% while PII that contained monoisatin moiety showed a lower inhibition efficiency of 74.8%. Both compounds had an increase in inhibition efficiencies percentage as concentrations increased. Density functional theory (DFT) was used to determine the correlation between the corrosion inhibition efficiency and electronic parameters. The DFT calculations indicated that the corrosion inhibition efficiency was mainly dependant on the frontier orbital energy gap and the chemical softness/hardness of the imines.
The syntheses of salicylideneaniline (L1a) and 4-hydroxybenzalaniline (L1b) was carried out via condensation reaction giving yields of 80.74% and 81.65% respectively. The compounds were characterised by physical and spectroscopic techniques, namely melting point, micro elemental analysis (C, H and N), 1H Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectroscopy. The characteristic n(C=N) peaks were observed at 1615 cm-1 and 1575 cm-1 respectively. Chronoamperometry (CA) was employed to electrodeposit both compounds on mild steel at 0.1 M inhibitor concentration in 0.3 M NaOH at three different potentials, +0.8 V, +1.05 V and +1.7 V. Formation of yellow imine films was observed on the mild steel. The corrosion behaviour of coated and uncoated mild steel was studied using Linear Polarization Resistance (LPR) in 0.5 M NaCl. Coated mild steel showed better corrosion resistance and with the highest inhibition efficiency of 90.34%, L1a provides a better protection against corrosion for mild steel than L1b.
In the electrodeposition system, adding saccharin alters the properties of the metal deposits by changing the electrode kinetics of the deposited surface. In this study, nanocrystalline cobalt-iron (CoFe) coating was synthesised using the electrodeposition technique with different saccharin concentrations. The results obtained showed that the coating thickness increased while the grain size decreased from 51 nm to 40 nm when the saccharin concentration increased from 0 to 2 g/L. The nanocrystalline CoFe coating produced with 2 g/L of saccharin concentration resulted in the smallest particle size of 71.22 nm and the highest microhardness of 251.86 HV. From the salt spray test (24 and 48 hours) it was found that the use of saccharin at higher concentration of 2 g/L improves the corrosion resistance of the nanocrystalline CoFe coating significantly due to the change of surface morphology as well as the decrease in grain size.
Strength and durability are important characteristics of concrete and desired engineering properties. Exposure to aggressive environment threatens durability of concrete. Previous studies on bio-concrete using several types of bacteria, including sulphate reduction bacteria (SRB), had to increase durability of concrete have shown promising results. This study used mixtures designed according to concrete requirement for sea water condition with SRB composition of 3%, 5% and 7% respectively. The curing time were 28, 56 and 90 days respectively. The mechanical properties, namely compressive strength and water permeability, were tested using cube samples. The results showed compressive strength had higher increase than the control at 53.9 Mpa. The SRB with 3%composition had maximum water permeability. Thus, adding SRB in concrete specimens improves compressive strength and water permeability. This is particularly suitable for applications using chloride ion penetration (sea water condition) where corrosion tends to affect durability of concrete constructions.
316L stainless steel is a common biomedical material. Currently, biomedical parts are produced through powder injection molding (PIM). Carbon control is the most critical in PIM. Improper debinding can significantly change the properties of the final product. In this work, thermal debinding and sintering were performed in two different furnaces (i.e. laboratory and commercially available furnaces) to study the mechanical properties and corrosion resistance. Debounded samples were sintered in different atmospheres. The samples sintered in inert gas showed enhanced mechanical properties compared with wrought 316L stainless steel and higher corrosion rate than those sintered in the vacuum furnace. The densification and tensile strength of the hydrogen sintered samples increased up to 3% and 51%, respectively, compared with those of the vacuum-sintered samples. However, the samples sintered in inert gas also exhibited reduced ductility and corrosion resistance. This finding is attributed to the presence of residual carbon in debonded samples during debinding.