cause and effect of corrosion

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Effect of corrosion on abrasive wear in a range of materials

Effect of corrosion on abrasive wear in a range of materials

The two ceramics, Zirconia and Diamond-Like Carbon (DLC) coating, exhibited superior resistance to sliding abrasion. Studies have shown that the erodent must be 1.2 times harder than the target to cause severe fracture in abrasion events [27]. Hence, the excellent performance of the ceramics is associated with their high bulk hardness. The immunity of ceramics to corrosion provides additional advantages in engineering cases were corrosion abrasion is apparent. However, the fluid sealing engineering parts experience more than one deterioration phenomena which makes their mitigation more challenging. Corrosion-abrasion and impact is one of the most aggressive degradation events which can occur on mechanical seals (valve and seats). To counteract this type of damage, the selected material must exhibit good corrosion resistance, a great bulk hardness and relatively high fracture toughness to undertake the high impact energies. Although the Zirconia ceramic and the DLC coating exhibit great abrasion resistance, their low fracture toughness (up to 7 MPa · m 1/2 ) make them vulnerable to cracking at high impact energies. Their low fracture toughness and their high manufacturing cost (refer to Figure 8) are the main selection drawbacks for fluid sealing applications.
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Effect of corrosion on abrasive wear in a range of materials

Effect of corrosion on abrasive wear in a range of materials

The two ceramics, Zirconia and Diamond-Like Carbon (DLC) coating, exhibited superior resistance to sliding abrasion. Studies have shown that the erodent must be 1.2 times harder than the target to cause severe fracture in abrasion events [27]. Hence, the excellent performance of the ceramics is associated with their high bulk hardness. The immunity of ceramics to corrosion provides additional advantages in engineering cases were corrosion abrasion is apparent. However, the fluid sealing engineering parts experience more than one deterioration phenomena which makes their mitigation more challenging. Corrosion-abrasion and impact is one of the most aggressive degradation events which can occur on mechanical seals (valve and seats). To counteract this type of damage, the selected material must exhibit good corrosion resistance, a great bulk hardness and relatively high fracture toughness to undertake the high impact energies. Although the Zirconia ceramic and the DLC coating exhibit great abrasion resistance, their low fracture toughness (up to 7 MPa · m 1/2 ) make them vulnerable to cracking at high impact energies. Their low fracture toughness and their high manufacturing cost (refer to Figure 8) are the main selection drawbacks for fluid sealing applications.
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Study on Effect of Corrosion in Blended Cements

Study on Effect of Corrosion in Blended Cements

Bong SeokJang, Byung Hwan Oh (2010) studied the effects of non-uniform corrosion distribution, cover-to-rebar diameter ratio, and concrete compressive strength on the cracking pressure of concrete cover. The study indicates that the pressures to cause cracking of concrete cover under non-uniform corrosion conditions are much smaller than those under uniform corrosion case. HuiYu, Xianming Shi, William H. Hartt, Baotong Lu (2010) studied the Time-to- corrosion (Ti) of reinforcement in concrete and chloride threshold content (Cth) are important service life determinants for reinforced concrete structures in chloride-laden environments. The results indicate that the corrosion initiation of rebar in concrete slabs depends upon both cement alkalinity and superplasticizer.
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Effect of Gas Flaring on Corrosion of Metals

Effect of Gas Flaring on Corrosion of Metals

The results from this work show that water from the flare zone of Ogbogu flow station has a higher corrosive effect on metals as a result of gas flaring which is mainly the primary cause of the high corrosive effect of the water on metals. The flared gas which is as a result of drilling activities going on within Egi area releases poisonous gases to the atmosphere, such as includes: Carbon dioxide (CO 2 ),

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Effect of Nanocrystalline Structure on the Corrosion of a Fe20Cr Alloy

Effect of Nanocrystalline Structure on the Corrosion of a Fe20Cr Alloy

Literature suggests that the process used to produce nanocrystalline surfaces may cause significant chemical and physical changes in addition to the grain refinement [14]. As such, in the light of issues described above, for the investigation of role of nanocrystalline structure on the corrosion behaviour of Fe-Cr alloys, it is necessary to produce the test specimen with the grain size in two distinct sizes by similar route. As such, Fe20Cr alloy tests specimens used in the current study were prepared by ball-milling followed by annealing, compaction and sintering; to the best of authors’ knowledge this is the first study addressing the passivation behaviour of ball-milled nanocrystalline Fe-Cr based alloys.
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Localized Deformation as a Primary Cause of Irradiation Assisted Stress Corrosion Cracking

Localized Deformation as a Primary Cause of Irradiation Assisted Stress Corrosion Cracking

The existing IASCC database can be evaluated with respect to the stacking fault energy to show that there is a strong correlation between IG cracking and SFE. The %IGSCC in irradiated austenitic alloys is shown as a function of SFE [16] in Figure 1-4. Note that there is a sharp threshold in IGSCC at a specific value of SFE (shown by the dashed line) such that high SFE alloys are resistant to IGSCC while low SFE alloys suffer much greater IGSCC. By far, the largest amount of data on IASCC is for 304 and 316 stainless steels. Generally, 316 SS is less susceptible to IASCC than is 304 SS. [4] By virtue of the higher Ni content in 316 SS, the SFE is higher, which correlates with greater IGSCC resistance. Figure 1-5 provides additional data plotted so as to show the combined effect of SFE and irradiation. Since IGSCC decreases with SFE but increases with dose,
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The effect of notches and pits on corrosion fatigue strength

The effect of notches and pits on corrosion fatigue strength

Corrosion fatigue is a phenomenon that results from the synergistic coupling of a corrosive environment and cyclic loading. The damage from corrosion fatigue is more severe than the summation o f the damage wrought by each form o f attack occurring separately. When considered in the broadest sense of environment-cyclic stress interaction, it can be seen that corrosion fatigue is a frequent cause o f in service failure, and in fact may well be the leading cause [93]. The fatigue part o f the failure is usually easily recognised by the flat fracture surface with striations and beach marks. The corrosion part of a failure is not easily seen, however a crack starting at the base o f a pit is considered conclusive evidence of corrosion fatigue. Corrosion fatigue can have huge effects on the fatigue strength o f materials. In many cases it has been observed that the fatigue limit seen with ferrous materials in air is lost. The loss o f fatigue limit can clearly been seen in Figure 28 [94] with both air and
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Effect of velocity in erosion corrosion

Effect of velocity in erosion corrosion

impact being spread out over a wider area (Levy, 1995). This will lead to a shallower depth of penetration and therefore the erosion damage will not significantly change even though the mass and size of the particle is greater. Another reason for this phenomenon is that as particles increase in size there are more particle interactions which may inhibit certain particles from contacting the metal surface. Larger particles at the metal surface may hinder other particles from coming in contact with the surface. Particles less than 175 micron yielded lower erosion rates than those in the range of 175-900 microns given above (Nesis.S and J.postlethwaite, 1993). This is because the smaller particles have less kinetic energy and therefore cause less erosion damage (Levy, 1995).
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Effect of Cracking on Corrosion of Steel in Concrete

Effect of Cracking on Corrosion of Steel in Concrete

by Reinhardt and Jooss (2003) where cracked concrete having crack widths of 0.05, 0.1 and 0.15 mm reduced the water flow rate by 97, 95 and 85%, respectively after 300 h of flow test. The concrete in their study contained about 10% fly ash and 10% micro silica. According to them the sig- nificant reduction in water flow is due to self-healing of the cracks. Their research also shows that higher temperatures such as 50 and 80 °C favour the growth of self-healed products in the same crack width than at 20 °C, presumably due to the faster hydration reaction at higher temperature. Evidence of effect of self-healing of micro-cracks on the water permeability of fibre reinforced cementitious com- posites (FRCCs) is also observed in Nishiwaki et al. (2014)’s study where water permeability significantly reduced in cracked FRCC having crack widths below 0.2 mm due to the self-healing of those cracks. The only reported study where the corrosion current of steel was measured in self- healed crack concrete containing fly ash and slag in a long term study of 15 years in marine environment (Mohammed et al. 2002). In that study three types of cements were used namely the OPC, slag cements of type A, B and C (SCA, SCB and SCC) and fly ash cement. Their results show that the small crack widths (* 0.5 mm) healed autogenously irrespective of type of binder in the concrete as evidenced by the measured low micro-cell current density shown in Fig. 15. Significantly lower current density were observed in above concretes containing smaller crack widths (e.g., below 0.3 mm crack width) (see the bottom graph in Fig. 15) than that of bigger crack widths as shown in top graph in Fig. 15. The formation of self-healed products on those smaller cracks is the cause for such low current density. Among various concretes having same crack width, the concretes containing fly ash and slag exhibited lower current density than that of control OPC concrete, even the concretes con- taining fly ash and slag having bigger crack widths (e.g., 0.2 and 0.3 mm) exhibited lower current densities than OPC concrete with 0.1 mm crack width. The continued poz- zolanic activity of fly ash and slag is responsible for the formation of more self-healed and hydration products on the crack surface which reduced the ingress of chloride ions and subsequent reduction of corrosion.
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3rd Person Cause And Effect Essay >>>CLICK HERE<<<

3rd Person Cause And Effect Essay >>>CLICK HERE<<<

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Effect of aspirin on all cause mortality in the healthy elderly

Effect of aspirin on all cause mortality in the healthy elderly

tors were unaware of the trial-group assignments. The adjudicators examined the progression of the final illness or incident and assigned an underly- ing cause of death, which was considered to be the single disease that was most likely to have initiated the trajectory toward death. Discordant adjudications were resolved through consensus. In cases of death in which relevant records could not be obtained, the underlying cause of death was based on International Classification of Diseases, 10th Revision (ICD-10), codes that were recorded on the death certificate or on the results of a search of the National Death Index.
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Semi-generative modelling: learning with cause and effect features

Semi-generative modelling: learning with cause and effect features

Finally, we wish to point out that our semi-generative model provides a general approach to SSL with cause and effect features which can also be applied to purely observational data, i.e., when no domain change occurs. It is then natural to ask whether we can give any guarantees that the semi-supervised solution will actually improve over—or at least not get worse than—the supervised one on the entire training set, when performing such SSL with cause and effect features. Recent work on such safe, pessimistic SSL has shown that for many popular surrogate losses such guarantees are impossible (Krijthe and Loog, 2016). However, in terms of the likelihood this is, in principle, possible, and for particular classifiers improvement can be shown to occur almost surely (Loog, 2016). As the semi- generative likelihood optimised by our approach seems to be a good performance indicator when our model is correct, such guarantees would thus be quite reassuring. Since our problem structure (X C → Y → X E ) gives rise to a more complex likelihood than the
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Effect of Corrosion Inhibitor in Mild Steel Bar

Effect of Corrosion Inhibitor in Mild Steel Bar

ABSTRACT: The explorative study made on corrosion of mild steel by accelerating corrosion by galvanostatic method. Different corrosion inhibitors as such paint coated, mortar coated, slurry coated and green corrosion inhibitor was used. This project intended to move our community towards green corrosion inhibitor. In view of this green corrosion inhibitor was developed from Azadirachtaindica (Neem) and Crossandrainfundibuliformis (Kanagamaram) plants leaves. The experimental results show that, the corrosion process alters the external surface by pitting. The rate of corrosion has been calculated by mass loss rate. The study clearly shows that the bar coated with slurry is efficient than other coating. The inhibition efficiency of the selected plant material on the mild steel dissolution in acidic media is assessed and found to be best replacement of inorganic with organic corrosion inhibitor, environmentally safe materials for corrosion resistance. Investigation results that corrosion rate is proportional to temperature and inversely proportional to pH medium. The present investigation is evident for the application and development of green corrosion inhibitor.
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Effect of Oilfield Produced Water on Corrosion of Pipeline

Effect of Oilfield Produced Water on Corrosion of Pipeline

type, and could inhibit both cathodic and anodic reaxtions. Silva et al. [11] investigated corrosion and inhibition of carbon steel in the simulating produced water generated in oil and gas extraction by weight loss, electrochemical methods and surface analysis. They indicated that the simulated produced water W 1 had a lower corrosion rate than W 2 , and iron dissolution was accompanied with an adsorbed

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Oxidative stress and nitration in neurodegeneration: Cause, effect, or association?

Oxidative stress and nitration in neurodegeneration: Cause, effect, or association?

Concluding comments and future directions Currently, there is sufficient documentation to place oxidative and nitrative processes in the center of the pathogenic mechanism that leads to neuronal loss and neurodegeneration. However, despite years of research efforts, the proximal sites of reactive-species generation remain elusive. A number of pathways have been identified as potential contributors, includ- ing the mitochondrial electron-transport chain, dopamine, membrane NADPH oxidases, and cytoso- lic flavoproteins. The most recent data have also iden- tified nitric oxide–derived reactive nitrogen interme- diates as critical contributors of protein modification and cell injury, providing potential targets for thera- peutic interventions. Consideration should be also given to inappropriate regulation of iron and other divalent redox metals such as copper, as well as to redox-inactive zinc. Recent data have identified genet- ic defects that lead to iron accumulation in neurode- generative diseases. Mutations in the gene that encodes the main iron-storage protein ferritin light polypeptide cause dominant adult-onset basal ganglia disease (75). Its presentation includes extrapyramidal features similar to those of Huntington disease and Parkinson disease with abnormal aggregation of fer- ritin and iron deposits. Abnormal iron accumulation and formation of α-synuclein inclusions that promi- nently feature tyrosine-nitrated α-synuclein are fea- tures of iron accumulation type 1 disease (76). This disease also presents with extrapyramidal dysfunction and a defect in the pantothenate kinase gene. As is mentioned above metals could drive the generation of strong oxidants and nitrating agents or directly be involved in the aggregation processes of proteins such as α-synuclein, amyloid, ferritin, or other proteins.
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Apoptotic mechanisms in Alzheimer neurofibrillary degeneration: cause or effect?

Apoptotic mechanisms in Alzheimer neurofibrillary degeneration: cause or effect?

Alzheimer disease (AD), the most com- mon cause of dementia in the elderly, is associated with senile plaques and neurofibrillary tangles (NFTs), but the relationship between these two neuro- pathologic lesions has been difficult to discover. Senile plaques are heterogenous lesions composed of extracellular amyloid β protein (Aβ), dystrophic neuronal pro- cesses, and reactive glia (1), while NFTs are intracellular lesions composed of fila- mentous aggregates of the microtubule- associated protein tau (2). Genetic factors have implicated Aβ in the pathogenesis of AD since mutations are found in the Aβ precursor (APP) as well as in enzymes involved in the production of Aβ (reviewed
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Cybernetic Approach for Interdepartmental Cause effect Relationship Modelling

Cybernetic Approach for Interdepartmental Cause effect Relationship Modelling

Logistics has the task, as a cross functional department, of aligning the interdependencies between departments within the scope of holistic coordination [3]. One possibility of implementing these cross functions by way of logistical processes is to encourage collaboration between departments [26]. Collaboration in the sense of logistics is understood as collaboration between two or more departments (internal collaboration) or between two or more companies (external collaboration), in order to exchange information or resources, come to common decisions and to seek to achieve common objectives [27,28]. The impact of a lack of external collaboration in supply chains is comprehensively illustrated by the bullwhip effect [29,30]. Due to the lack of coordination and having no interchange of information in customer-supply relations, the bullwhip effect describes the increasing extreme fluctuations of demand levels in directions opposing the value adding process, the growing likelihood of supply delays and the consequent need to maintain higher stock levels. Possible results of closer collaboration may include increasing revenues, reducing costs, and achieving higher operative flexibility in order to respond to fluctuations in demand [30,31]. Against the background of a systematic development of collaboration between decision makers, it is necessary to shape the dimensions of cooperation, coordination and communication [32]. These three dimensions can be influenced by way of collaborative measures [33]. In the course of cooperation, key measures are boosting interdepartmental cooperation and transferring responsibilities to employees. Coordination covers the consideration of an overarching system of objectives by all decision makers as well as bundling of resources across all decision makers. Communication as the third dimension of collaboration includes the exchange of information between decision makers and the full consideration of knowledge existing amongst them.
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Effect of Microstructure on Corrosion of Structural and Advanced Alloys

Effect of Microstructure on Corrosion of Structural and Advanced Alloys

bars generally have an outer layer consisted of tempered martensite phase and an inner core made of ferrite-pearlite phases. The combination of different phases in these steel bars improves the load-bearing and ductility of these steels compare to the single-phase bars [10,12,15]. Unless specifically mentioned, both of the above-mentioned bars can be embedded in concrete [17,18], thus; in practice, both types of steels may be connected and used together. Since these steels have different phases and approximately 10% of the surafce was pre-eutectoid α-ferrite for as-received specimens while this amount for fine and coarse specimens were 18% and 6.5% of surface area, respectively. this connection could lead to corrosion, particularly in the joints, due to galvanic effect. The objective of this work was to evaluate and compare the passivation and corrosion behavior of steel bars with different microstructures, individually and when they were connected.
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EFFECT OF Ca2+ ON C02 CORROSION OF CARBON STEEL

EFFECT OF Ca2+ ON C02 CORROSION OF CARBON STEEL

The temperature strongly influences the C0 2 corrosion due to its effect on the rate of protective iron carbonate layer formation.Corrosion rates generally increase[r]

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Effect of Ggbfs on Corrosion Potential of Steel in Concrete

Effect of Ggbfs on Corrosion Potential of Steel in Concrete

concrete structures is one of the important reasons of premature failure in durability criteria, particularly along coastal regions. Supplementary cementitious materials (SCM) are widely used for enhancing the durability and other properties of concrete. In this paper an experimental investigation has been carried out to study the corrosion potential of steel in concrete when Ground Granulated Blast Furnace Slag (GGBFS) is added. Corrosion test specimen with 25% and 50% replacement of cement with GGBFS has been prepared along with the reference specimen with OPC (400 kg/m 3 ) and w/b ratio varied from 0.40 to 0.50. Alternate
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