Modification of D-W model for corrosion rate of shale gas pipeline under the synergistic corrosion of SRB and CO2

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xingyu Peng ◽  
Xinyue Liu
Keyword(s):  
Corrosion Rate ◽  
Shale Gas ◽  
Correlation Method ◽  
Most Probable Number ◽  
Linear Regression Method ◽  
Corrosion Morphology ◽  
Probable Number ◽  
Content Type ◽  
Gray Correlation ◽  
Weight Loss Method

Purpose The purpose of this paper is to develop an equation for the synergistic corrosion of SRB and CO2 based on the D-W model. Design/methodology/approach The bacterial types in the a and ß pipelines were studied by the most probable number method, and the corrosion morphology of L360 in pipeline water samples was studied by surface analysis. The corrosion rate of L360 was studied using the weight loss method. The gray correlation method was used to calculate the degree of correlation between the influencing factors of corrosion under the synergistic effect of CO2 and SRB. The curve obtained from PIPESIM software and experiments data was then fitted using multiple non-linear regression method by MATLAB software. Findings The equation was used to predict the corrosion of the ß pipeline for verification, and it was found that seven out of ten excavation sites were within a 20% error range. Originality/value Using the gray correlation method, an equation that considers synergistic corrosion of SRB and CO2 has been developed based on the D-W model. The equation could be used to predict the corrosion rate of shale gas gathering pipelines through SRB and CO2 synergistic corrosion.

scholarly journals Long-Term Study of Vibrio parahaemolyticus Prevalence and Distribution in New Zealand Shellfish

2015 ◽  
Vol 81 (7) ◽  
pp. 2320-2327 ◽  
Author(s):  
C. D. Cruz ◽  
D. Hedderley ◽  
G. C. Fletcher
Keyword(s):  
New Zealand ◽  
Vibrio Parahaemolyticus ◽  
Most Probable Number ◽  
Pcr Analysis ◽  
Potential Hazard ◽  
Probable Number ◽  
Content Type ◽  
The North ◽  
Long Term Study ◽  
Food Borne

ABSTRACTThe food-borne pathogenVibrio parahaemolyticushas been reported as being present in New Zealand (NZ) seawaters, but there have been no reported outbreaks of food-borne infection from commercially grown NZ seafood. Our study determined the current incidence ofV. parahaemolyticusin NZ oysters and Greenshell mussels and the prevalence ofV. parahaemolyticustdhandtrhstrains. Pacific (235) and dredge (21) oyster samples and mussel samples (55) were obtained from commercial shellfish-growing areas between December 2009 and June 2012. TotalV. parahaemolyticusnumbers and the presence of pathogenic genestdhandtrhwere determined using the FDA most-probable-number (MPN) method and confirmed using PCR analysis. In samples from the North Island of NZ,V. parahaemolyticuswas detected in 81% of Pacific oysters and 34% of mussel samples, while the numbers ofV. parahaemolyticustdhandtrhstrains were low, with just 3/215 Pacific oyster samples carrying thetdhgene.V. parahaemolyticusorganisms carryingtdhandtrhwere not detected in South Island samples, andV. parahaemolyticuswas detected in just 1/21 dredge oyster and 2/16 mussel samples. Numbers ofV. parahaemolyticusorganisms increased when seawater temperatures were high, the season when most commercial shellfish-growing areas are not harvested. The numbers ofV. parahaemolyticusorganisms in samples exceeded 1,000 MPN/g only when the seawater temperatures exceeded 19°C, so this environmental parameter could be used as a trigger warning of potential hazard. There is some evidence that the totalV. parahaemolyticusnumbers increased compared with those reported from a previous 1981 to 1984 study, but the analytical methods differed significantly.

scholarly journals Repeated Anaerobic Microbial Redox Cycling of Iron

2011 ◽  
Vol 77 (17) ◽  
pp. 6036-6042 ◽  
Author(s):  
Aaron J. Coby ◽  
Flynn Picardal ◽  
Evgenya Shelobolina ◽  
Huifang Xu ◽  
Eric E. Roden
Keyword(s):  
Microbial Communities ◽  
Microscopic Analysis ◽  
Redox Cycling ◽  
Most Probable Number ◽  
Rrna Gene ◽  
Electron Microscopic ◽  
16S Rrna Gene Analysis ◽  
Probable Number ◽  
Content Type ◽  
Floodplain Sediments

ABSTRACTSome nitrate- and Fe(III)-reducing microorganisms are capable of oxidizing Fe(II) with nitrate as the electron acceptor. This enzymatic pathway may facilitate the development of anaerobic microbial communities that take advantage of the energy available during Fe-N redox oscillations. We examined this phenomenon in synthetic Fe(III) oxide (nanocrystalline goethite) suspensions inoculated with microflora from freshwater river floodplain sediments. Nitrate and acetate were added at alternate intervals in order to induce repeated cycles of microbial Fe(III) reduction and nitrate-dependent Fe(II) oxidation. Addition of nitrate to reduced, acetate-depleted suspensions resulted in rapid Fe(II) oxidation and accumulation of ammonium. High-resolution transmission electron microscopic analysis of material from Fe redox cycling reactors showed amorphous coatings on the goethite nanocrystals that were not observed in reactors operated under strictly nitrate- or Fe(III)-reducing conditions. Microbial communities associated with N and Fe redox metabolism were assessed using a combination of most-probable-number enumerations and 16S rRNA gene analysis. The nitrate-reducing and Fe(III)-reducing cultures were dominated by denitrifyingBetaproteobacteria(e.g.,Dechloromonas) and Fe(III)-reducingDeltaproteobacteria(Geobacter), respectively; these same taxa were dominant in the Fe cycling cultures. The combined chemical and microbiological data suggest that bothGeobacterand variousBetaproteobacteriaparticipated in nitrate-dependent Fe(II) oxidation in the cycling cultures. Microbially driven Fe-N redox cycling may have important consequences for both the fate of N and the abundance and reactivity of Fe(III) oxides in sediments.

Corrosion behaviors of X70 steel under direct current interference

2019 ◽  
Vol 66 (3) ◽  
pp. 307-316 ◽  
Author(s):  
Jun Wang ◽  
Zili Li ◽  
Gan Cui ◽  
JianGuo Liu ◽  
Chuanping Kong ◽  
...  
Keyword(s):  
Weight Loss ◽  
Corrosion Rate ◽  
Soil Solution ◽  
Direct Current ◽  
Polarization Curves ◽  
Solution Ph ◽  
Corrosion Morphology ◽  
Content Type ◽  
Tafel Polarization ◽  
Corrosion Behaviors

Purpose The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution. Design/methodology/approach The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy. Findings The results showed that E-I polarization curves under 200-1,200 A/m2 interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution. Originality/value All tests were conducted at a relative higher DC density (200-1,200 A/m2). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.

Combination of experiments and CFD analysis for in-flight wings deflections estimation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamid Reza Ovesy ◽  
Ali Gharibi ◽  
Reza Khaki
Keyword(s):  
Correlation Method ◽  
Linear Regression Method ◽  
Cfd Analysis ◽  
Concentrated Load ◽  
Flight Tests ◽  
Content Type ◽  
Aerodynamic Loads ◽  
Rear Wing ◽  
Alternative Approach ◽  
Ground Test

Purpose This study aims to develop a new correlation method for prediction of in-flight wings deflections by integration of the experimental ground tests with computational fluid dynamics (CFD) analysis. Design/methodology/approach The ground test results are implemented in the curve fitting process to determine deflections at 66 specific points (SPs) on the front and rear wing torque box. By using the obtained deflections and the corresponding applied loads, an experimental deflection equation (EDE) for each point is established through the Castigliano’s theorem. The CFD aerodynamic loads of typical aircraft, which have been obtained earlier by the authors, are once again used in the current research. The total applied loads to each part are achieved via summation of inertia and aerodynamic loads. The obtained loads are transformed to the equivalent concentrated loads at the SPs. By substituting the concentrated load values in the EDEs, the SPs deflections are achieved for mentioned flight conditions. The resulted deflections and the corresponding input flight parameters, i.e. M and α, are incorporated into a linear regression method for development of the appropriate in-flight deflection equations (IFDEs). The validity of IFDEs is approved by comparing IFDEs’ deflections with the corresponding ones calculated through EDEs for different flight conditions. Findings As an alternative approach to the fairly expensive flight tests, the IFDEs can be used to predict the in-flight wing deflections with comparable degree of accuracy. Originality/value Prediction of actual wing deflections distributions without flight tests execution at any given flight condition.

scholarly journals Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

2016 ◽  
Vol 83 (5) ◽  
Author(s):  
Vaibhav C. Gole ◽  
Rebecca Woodhouse ◽  
Charles Caraguel ◽  
Talia Moyle ◽  
Jean-Loup Rault ◽  
...  
Keyword(s):  
Production System ◽  
Salmonella Enterica ◽  
Egg Production ◽  
Production Systems ◽  
Most Probable Number ◽  
Probable Number ◽  
Content Type ◽  
Free Range ◽  
Phage Types ◽  
Positive Correlations

ABSTRACT The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variable-number tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates (n = 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA, ironA, and misL. There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters. IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella serovars in a free-range egg production system. Given that there is increasing demand for free-range eggs, it is essential to understand the risks associated with such a production system.

scholarly journals Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Arman Abdullah ◽  
Nordin Yahaya ◽  
Norhazilan Md Noor ◽  
Rosilawati Mohd Rasol
Keyword(s):  
Weight Loss ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Sulfate Reducing Bacteria ◽  
Desulfovibrio Vulgaris ◽  
Corrosion Morphology ◽  
Sulfate Reducing ◽  
Weight Loss Method ◽  
Loss Method ◽  
Reducing Bacteria

Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP), and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR) of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr forDesulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.

scholarly journals Distribution and Characterization of Salmonella enterica Isolates from Irrigation Ponds in the Southeastern United States

2015 ◽  
Vol 81 (13) ◽  
pp. 4376-4387 ◽  
Author(s):  
Zhiyao Luo ◽  
Ganyu Gu ◽  
Amber Ginn ◽  
Mihai C. Giurcanu ◽  
Paige Adams ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Geometric Mean ◽  
Multidrug Resistant ◽  
Most Probable Number ◽  
Sample Type ◽  
Probable Number ◽  
Content Type ◽  
Safety Standards ◽  
Produce Contamination ◽  
Southern Georgia

ABSTRACTIrrigation water has been implicated as a likely source of produce contamination bySalmonella enterica. Therefore, the distribution ofS. entericawas surveyed monthly in irrigation ponds (n= 10) located within a prime agricultural region in southern Georgia and northern Florida. All ponds and 28.2% of all samples (n= 635) were positive forSalmonella, with an overall geometric mean concentration (0.26 most probable number [MPN]/liter) that was relatively low compared to prior reports for rivers in this region.Salmonellapeaks were seasonal; the levels correlated with increased temperature and rainfall (P< 0.05). The numbers and occurrence were significantly higher in water (0.32 MPN/liter and 37% of samples) than in sediment (0.22 MPN/liter and 17% of samples) but did not vary with depth. Representative isolates (n= 185) from different ponds, sample types, and seasons were examined for resistance to 15 different antibiotics; most strains were resistant to streptomycin (98.9%), while 20% were multidrug resistant (MDR) for 2 to 6 antibiotics. DiversiLab repetitive extragenic palindromic-element sequence-based PCR (rep-PCR) revealed genetic diversity and showed 43 genotypes among 191 isolates, as defined by >95% similarity. The genotypes did not partition by pond, season, or sample type. Genetic similarity to known serotypes indicated Hadar, Montevideo, and Newport as the most prevalent. All ponds achieved the current safety standards for genericEscherichia coliin agricultural water, and regression modeling showed that theE. colilevel was a significant predictor for the probability ofSalmonellaoccurrence. However, persistent populations ofSalmonellawere widely distributed in irrigation ponds, and the associated risks for produce contamination and subsequent human exposure are unknown, supporting continued surveillance of this pathogen in agricultural settings.

scholarly journals Correlation between Quantitative PCR and Culture-Based Methods for Measuring Enterococcus spp. over Various Temporal Scales at Three California Marine Beaches

2011 ◽  
Vol 78 (4) ◽  
pp. 1237-1242 ◽  
Author(s):  
Reagan R. Converse ◽  
John F. Griffith ◽  
Rachel T. Noble ◽  
Richard A. Haugland ◽  
Kenneth C. Schiff ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Membrane Filtration ◽  
Empirical Relationship ◽  
Time Of Day ◽  
Most Probable Number ◽  
Spatial And Temporal Variability ◽  
Culture Methods ◽  
Fecal Indicator ◽  
Probable Number ◽  
Content Type

ABSTRACTSeveral studies have examined how fecal indicator bacteria (FIB) measurements compare between quantitative PCR (qPCR) and the culture methods it is intended to replace. Here, we extend those studies by examining the stability of that relationship within a beach, as affected by time of day and seasonal variations in source.Enterococcusspp. were quantified at three southern California beaches in the morning and afternoon using two qPCR assays, membrane filtration, and defined-substrate testing. While qPCR and culture-based measurements were consistently and significantly correlated, strength of the correlation varied both among and within beaches. Correlations were higher in the morning (0.45 < ρ < 0.74 [P< 0.002]) than in the afternoon (0.18 < ρ < 0.45 [P< 0.021]) and higher when the fecal contamination was concentrated (0.38 < ρ < 0.83 [P< 0.001]) than when it was diffuse (0.19 < ρ < 0.34 [P< 0.003]). The ratios of culture-based and qPCR results (CFU or most probable number [MPN] per calibrator cell equivalents [CCE]) also varied spatially and temporally. Ratios ranged between 0.04 and 0.85 CFU or MPN per CCE and were lowest at the beach affected by diffuse pollution. Patterns in the ratios over the course of the day were dissimilar across beaches, increasing with time at one beach and decreasing at another. The spatial and temporal variability we observed indicate that the empirical relationship between culture-based and qPCR results is not universal, even within a beach.

Shelf life study of handmade and industrially processed Minas frescal cheese

2019 ◽  
Vol 49 (6) ◽  
pp. 1207-1218
Author(s):  
Thamiris Evangelista Silva ◽  
Priscila Alonso dos Santos ◽  
Thamara Evangelista Silva ◽  
Kamilla Soares Silva ◽  
André Luiz Borges Machado ◽  
...  
Keyword(s):  
Microbiological Quality ◽  
Oxygen Demand ◽  
Storage Period ◽  
State Inspection ◽  
Most Probable Number ◽  
Probable Number ◽  
Content Type ◽  
Life Study ◽  
Thermotolerant Coliforms ◽  
Milk Pasteurisation

Purpose The purpose of this study is to characterize and compare the results of the inspection mark of handmade and industrially processed Minas frescal cheese. It is one of the most commonly made and consumed cheeses in Brazil, and its production processes range from handmade cheeses produced in small household production sites to cheeses manufactured in large dairy factories subject to federal inspection. Design/methodology/approach The samples were stored for 10 days at 4°C in a biochemical oxygen demand chamber. Cheeses were analyzed using physicochemical analyzes, yield and syneresis indices and microbiological analyses. Findings The cheese A met the criterion of regulatory classification for very high humidity (65.32 g/100 g), while cheese B did not meet the criterion (54.38 g/100 g). Cheeses A (19.01 g/100 g) and B (24 g/100 g) showed average fat contents that did not comply with current legislation. The most probable number per g of thermotolerant coliforms was outside the acceptable range (>24 × 102 MPN/g), and Salmonella spp. were present in the tested samples. The highest yield was observed for handmade cheese (an average of 5.35 L of milk to produce 1 kg of cheese), which had the highest syneresis during the storage period (p = 0.004), reaching 14.26% on the 10th day of storage. Originality/value Municipal and state inspection certificates do not ensure the microbiological quality of Minas frescal cheese, indicating flaws in the good manufacturing practices and/or in the milk pasteurisation stage.

scholarly journals Individual Predisposition to Staphylococcus aureus Colonization in Pigs on the Basis of Quantification, Carriage Dynamics, and Serological Profiles

2014 ◽  
Vol 81 (4) ◽  
pp. 1251-1256 ◽  
Author(s):  
Carmen Espinosa-Gongora ◽  
Jan Dahl ◽  
Anders Elvstrøm ◽  
Willem J. van Wamel ◽  
Luca Guardabassi
Keyword(s):  
Staphylococcus Aureus ◽  
Humoral Response ◽  
Nasal Carriage ◽  
Most Probable Number ◽  
Cross Sectional ◽  
Probable Number ◽  
Content Type ◽  
Luminex Assay ◽  
Nasal Swabs ◽  
Cross Sectional Design

ABSTRACTPrevious research onStaphylococcus aureusin pigs focused on livestock-associated methicillin-resistantS. aureus(MRSA) and had a qualitative cross-sectional design. This study aimed to elucidate the frequency, load, and stability ofS. aureusnasal carriage in pigs over time and investigated possible associations between carriage and immune response. Nasal swabs were collected three times weekly from 480 tagged adult pigs in 20 Danish production farms.S. aureusand MRSA were quantified on selective media by the most-probable-number method. The levels of IgG against 10S. aureusantigens in serum were quantified in selected pigs by a Luminex assay. All the farms were positive forS. aureusand 15 for MRSA, leading to overall prevalences of persistent and intermittent carriers and noncarriers of 24, 52, and 23%, respectively. Carriage frequency and nasal loads were significantly higher on MRSA-positive farms. Logistic-regression modeling revealed the presence of individual pigs characterized by high nasal loads (≥10,000 CFU per swab) and stable carriage regardless of farm- and pen-associated factors. On the other hand, the humoral response was strongly influenced by these environmental factors. The existence of a minority of shedders contributing to maintenance ofS. aureuswithin farms opens up new perspectives on the control of MRSA in pig farming.

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