scholarly journals Experimental Investigation on Corrosion of Cast Iron Pipes

2011 ◽  
Vol 2011 ◽  
pp. 1-17 ◽  
Author(s):  
H. Mohebbi ◽  
C. Q. Li
Keyword(s):  
Cast Iron ◽  
Service Life ◽  
Corrosion Behaviour ◽  
Experimental Program ◽  
Cast Irons ◽  
Remaining Service Life ◽  
Key Factor ◽  
Service Environments ◽  
Primary Form

It is well known that corrosion is the predominant mechanism for the deterioration of cast iron pipes, leading to the reduction of pipe capacity and ultimate collapse of the pipes. In order to assess the remaining service life of corroded cast iron pipes, it is imperative to understand the mechanisms of corrosion over a long term and to develop models for pipe deterioration. Although many studies have been carried out to determine the corrosion behavior of cast iron, little research has been undertaken to understand how cast iron pipes behave over a longer time scale than hours, days, or weeks. The present paper intends to fill the gap regarding the long-term corrosion behaviour of cast iron pipes in the absence of historical data. In this paper, a comprehensive experimental program is presented in which the corrosion behaviour of three exservice pipes was thoroughly examined in three simulated service environments. It has been found in the paper that localised corrosion is the primary form of corrosion of cast iron water pipes. It has also been found that the microstructure of cast irons is a key factor that affects the corrosion behaviour of cast iron pipes. The paper concludes that long-term tests on corrosion behaviour of cast iron pipes can help develop models for corrosion-induced deterioration of the pipes for use in predicting the remaining service life of the pipes.

Predicting the Remaining Service Life of Reinforced Concrete Members after Fire Exposure

2010 ◽  
Vol 163-167 ◽  
pp. 3094-3098
Author(s):  
Huai Liang Wang
Keyword(s):  
High Temperature ◽  
Service Life ◽  
Elevated Temperatures ◽  
Pullout Test ◽  
Empirical Models ◽  
Experimental Program ◽  
Percentage Reduction ◽  
Fire Exposure ◽  
Concrete Members ◽  
Remaining Service Life

An experimental program was conducted to investigate the effect of elevated temperatures on bond between reinforcing steel and concrete. By regressing the pullout test data, simple empirical models were proposed to predict the percentage reduction in bond strength accounted for effects of high temperature. Based on the empirical models, the resistance and the reliability of RC members after fire were analyzed using J.C. method. The engineering example indicates that the method of reliability analysis is suitable for predicting the change of post-fire resistance with temperature.

scholarly journals Verification of Actual Prestressing in Existing Pre-Tensioned Members

2021 ◽  
Vol 11 (13) ◽  
pp. 5971
Author(s):  
Jakub Kraľovanec ◽  
František Bahleda ◽  
Jozef Prokop ◽  
Martin Moravčík ◽  
Miroslav Neslušan
Keyword(s):  
Service Life ◽  
Prestressed Concrete ◽  
Concrete Structure ◽  
Comparative Method ◽  
Design Procedure ◽  
Experimental Program ◽  
Actual State ◽  
Prestress Losses ◽  
Remaining Service Life ◽  
Prestressing Force

In the case of prestressed concrete structures, information about the actual state of prestressing is an important basis for determining their load-carrying capacity as well as remaining service life. During the service life of the prestressed concrete structure, the initial level of prestressing is inevitably reduced as a result of the actions of various factors. These reductions of prestressing force are considered as prestress losses, which are influenced by construction stages, used materials, prestressing technology, or required length of service life. Available standards enable the determination of the expected values of prestress losses. Ultimately, their calculation is part of the design procedure of every prestressed concrete structure. However, aging and often neglected infrastructure in Europe is also exposed to factors, such as environmental distress, that are not considered in standard calculations. Therefore, verified and reliable methods for determining the actual state of prestressing are needed. This paper presents an experimental program of an indirect method for the evaluation of the value of prestressing force in seven prestressed concrete sleepers. Particularly, the non-destructive saw-cut method as a pivotal object of this study is performed and assessed. Furthermore, the Barkhausen noise technique is used as a comparative method. Subsequently, the experimental campaign is supported by the numerical analysis performed in the ATENA 3D software. Finally, the experimentally determined values of residual prestressing force are compared to the expected level of prestressing according to Eurocodes.

A methodology to estimate remaining service life of grey cast iron water mains

2000 ◽  
Vol 27 (6) ◽  
pp. 1259-1272 ◽  
Author(s):  
Balvant Rajani ◽  
Jon Makar
Keyword(s):  
Cast Iron ◽  
Service Life ◽  
Structural Integrity ◽  
Residual Life ◽  
Grey Cast Iron ◽  
Remaining Service Life ◽  
Structural Resistance ◽  
Water Mains ◽  
Pipe Segment ◽  
Grey Cast

The decision to repair, renew, or replace existing old grey cast iron mains is typically based on performance indicators such as structural integrity, hydraulic efficiency, system reliability, and water quality. Structural integrity (often quantified as the number of main breaks per kilometre or mile per year) is the most common performance indicator. However, these indicators represent past performance, rather than expected future performance. Decisions based on performance indicators may not, therefore, accurately meet the real needs of the utility owner of the water distribution system. A preferred approach to make decisions on pipe repair and replacement is to determine the expected remaining service (residual) life of each pipe segment and ensure that the necessary work is performed before failure occurs. Past efforts to estimate remaining service life of water mains have been based on corrosion pit depth and estimated corrosion rate with no regard to the influence of corrosion on the structural resistance capacity of water mains. This paper describes a methodology to estimate the remaining service life of grey cast iron mains that takes corrosion pit induced changes in the structural resistance capacity into account. The methodology combines the residual resistance capacity of grey cast iron mains, anticipated corrosion rates, and the measurement of corrosion pits by direct inspection or non-destructive evaluation technology to predict when the factor of safety of an individual pipe segment will fall below a minimum acceptable value set by the utility owner, i.e., remaining service life. The estimate of remaining service life may then be used to schedule appropriate maintenance or replacement of grey cast iron mains.Key words: water mains, remaining service life, residual life, repair, renew, or rehabilitate water mains, corrosion models, pit and spun grey cast iron.

scholarly journals Continuous Modification of Cast Iron By the FLORET Method

2012 ◽  
Vol 12 (3) ◽  
pp. 43-48
Author(s):  
A. Hanus ◽  
P. Hanusová
Keyword(s):  
Cast Iron ◽  
Basic Structure ◽  
Operating Conditions ◽  
Spheroidal Graphite ◽  
Cast Irons ◽  
Advantages And Disadvantages ◽  
Operational Tests ◽  
Materials Used ◽  
Theoretical Foundations

Abstract Increasing demands on the utility properties of materials used for castings have led to the production of cast iron with a modified shape of graphite, where the required properties are achieved by a change in graphite shape, its size and layout, and a change in the basic structure of the metal. This paper is focused on the continuous method of producing spheroidal graphite FLOTRET. In the introductory section is summarized the theoretical foundations of the secondary treatment of cast irons, especially the FLOTRET flow method, describes the advantages and disadvantages of the method. The practical part is divided into laboratory and operational tests. Laboratory experiments were conducted on a laboratory-type modifier FLOTRET chamber, which was designed and hydraulically optimized. Experiments were focused on the effects of pressure altitude and amount of modifier on the residual values of magnesium, as conditions for a successful modification. The method was tested in two foundries under operating conditions and in one of them was observed a long-term modification process.

Attachment of oral bacteria to titanium surfaces: An SEM study

1994 ◽  
Vol 52 ◽  
pp. 468-469
Author(s):  
J. E. Laffoon ◽  
R. L. Anderson ◽  
J. C. Keller ◽  
C. D. Wu-Yuan
Keyword(s):  
Technical Problem ◽  
Titanium Implant ◽  
Oral Bacteria ◽  
Bacterial Cells ◽  
Thin Sections ◽  
Surface Ultrastructure ◽  
Sem Study ◽  
Key Factor ◽  
Titanium Surfaces

Titanium (Ti) dental implants have been used widely for many years. Long term implant failures are related, in part, to the development of peri-implantitis frequently associated with bacteria. Bacterial adherence and colonization have been considered a key factor in the pathogenesis of many biomaterial based infections. Without the initial attachment of oral bacteria to Ti-implant surfaces, subsequent polymicrobial accumulation and colonization leading to peri-implant disease cannot occur. The overall goal of this study is to examine the implant-oral bacterial interfaces and gain a greater understanding of their attachment characteristics and mechanisms. Since the detailed cell surface ultrastructure involved in attachment is only discernible at the electron microscopy level, the study is complicated by the technical problem of obtaining titanium implant and attached bacterial cells in the same ultra-thin sections. In this study, a technique was developed to facilitate the study of Ti implant-bacteria interface.Discs of polymerized Spurr’s resin (12 mm x 5 mm) were formed to a thickness of approximately 3 mm using an EM block holder (Fig. 1). Titanium was then deposited by vacuum deposition to a film thickness of 300Å (Fig. 2).

A Possible Basis for Nondestructive Characterization of Ropes of Nylon 6

1997 ◽  
Vol 503 ◽  
Author(s):  
H. Jiang ◽  
M. K. Davis ◽  
R. K. Eby ◽  
P. Arsenovic
Keyword(s):  
Tensile Strength ◽  
Service Life ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Crystal Form ◽  
Nylon 6 ◽  
Remaining Service Life ◽  
Nondestructive Characterization ◽  
Fractional Content

ABSTRACTPhysical properties and structural parameters have been measured for ropes of nylon 6 as a function of the number of use operations. The fractional content of the α crystal form, sound velocity, birefringence, tensile strength and length all increase systematically and significantly with increasing the number of use operations. The fractional content of the γ crystal form and fiber diameter decrease with use. These trends indicate that the measurement of such properties and structural parameters, especially the length, provide a possible basis for establishing a reliable, rapid, and convenient nondestructive characterization method to predict the remaining service life of nylon 6 ropes.

Designing a CRM Framework for online & offline sports footwear retailers

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rodrigo Cueva ◽  
Guillem Rufian ◽  
Maria Gabriela Valdes
Keyword(s):  
Environmental Changes ◽  
Customer Relationship ◽  
Business Strategies ◽  
Economic Sectors ◽  
Running Shoes ◽  
Brick And Mortar ◽  
Key Factor ◽  
On Line ◽  
The Impact

The use of Customer Relationship Managers to foster customers loyalty has become one of the most common business strategies in the past years.  However, CRM solutions do not fill the abundance of happily ever-after relationships that business needs, and each client’s perception is different in the buying process.  Therefore, the experience must be precise, in order to extend the loyalty period of a customer as much as possible. One of the economic sectors in which CRM’s have improved this experience is retailing, where the personalized attention to the customer is a key factor.  However, brick and mortar experiences are not enough to be aware in how environmental changes could affect the industry trends in the long term.  A base unified theoretical framework must be taken into consideration, in order to develop an adaptable model for constructing or implementing CRMs into companies. Thanks to this approximation, the information is complemented, and the outcome will increment the quality in any Marketing/Sales initiative. The goal of this article is to explore the different factors grouped by three main domains within the impact of service quality, from a consumer’s perspective, in both on-line and off-line retailing sector.  Secondly, we plan to go a step further and extract base guidelines about previous analysis for designing CRM’s solutions focused on the loyalty of the customers for a specific retailing sector and its product: Sports Running Shoes.

ANALISA KETAHANAN AUS BESI COR EN-JN2019 DENGAN METODE FACTORIAL DESIGN TERHADAP UNSUR PADUAN DAN LAJU PENDINGINAN

2016 ◽  
Vol 6 (1) ◽  
pp. 11
Author(s):  
Kus Hanaldi
Keyword(s):  
Cast Iron ◽  
Factorial Design ◽  
Cast Irons ◽  
Wear Resistant

Salah satu material yang dapat digunakan pada kondisi lingkungan abrasif adalah white cast irons atau abrasion-resistant cast iron. EN-JN2019 adalah salah satu jenis besi cor yang dapat digunakan pada kondisi ini. Pada besi cor  ini terkandung unsur karbon, silikon, mangan, dan chromium. Analisa ketahanan aus material ini telah dilakukan dengan menggunakan factorial design terhadap dua kombinasi kandungan chromium (1% dan 2%), dua kombinasi kandungan silikon (1% dan 1,5%) dan dua kombinasi ketebalan sampel (5mm dan 30mm). Ketebalan sampel merupakan representasi dari laju pendinginan. Kajian terhadap kekerasan, struktur mikro, uji impact dan uji aus dari delapan sampel yang dihasilkan dari proses pengecoran telah dilaksanakan pula. Hasil pengujian kekerasan menunjukkan bahwa kekerasan menurun dengan meningkatnya ketebalan dan disertai dengan perubahan struktur mikro sebagai hasil dari laju pendinginan yang semakin lambat. Penambahan kandungan chromium meningkatkan kekerasan karena adanya pembentukan karbida. Penambahan kandungan silikon menurunkan kekerasan akibat pembentukan grafit yang lebih mudah. Pengaruh kandungan chromium dan silikon terhadap kekerasan memiliki ketergantungan  satu  dengan  lainnya,  karena  penambahan  silikon  menekan  pertumbuhan  karbida.  Dari  hasil pengujian impact didapatkan hasil, pada semua variasi chromium, silikon dan ketebalan tidak memiliki pengaruh terhadap harga impact. Sedangkan dari hasil pengujian keausan  didapatkan bahwa kekerasan  berbanding lurus dengan nilai wear resistant, semakin tinggi kekerasan maka nilai wear resistant akan semakin meningkat.Kata kunci: ketahanan aus, EN-JN2019, kandungan chromium, kandungan silikon, laju pendinginan, factorial design, pembentukan karbida.

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