Joint Leakage Research Articles

Development of Microbial Metabolic Processes to Repair Concrete Joint Leakage

This study proposes methods and examines the applicability of material generated from the metabolic processes of microorganisms to repair the leakage of concrete joints. Yeast was selected as the microorganism used for grout. The combination of yeast and a nutrition source with the largest amount of calcium carbonate extraction was found using the metabolic process of yeast. Calcium carbonate presence was determined by X-ray analysis. Water permeability of the concrete joint repaired with grout made from the largest yeast extraction was tested. From the results of the water permeability test, it is shown that grout made from the metabolic processes of yeast is capable of repairing a concrete joint.

Cooperative Beamforming for Cognitive Radio Systems with Asynchronous Interference to Primary User

In a cognitive radio (CR) network when a group of CR users acts as relays for a given CR user, a cooperative beamforming can be used to improve the quality of communications. However, this cooperative beamforming can introduce asynchronous interference at the primary receiver due to different propagation delays between different CR relays and the primary receiver. In this paper, we propose an innovative beamforming method that maximizes the received signal power at the secondary destination while keeping the asynchronous interference at the primary receiver below a target threshold. The presented numerical results show that the proposed beamforming method can significantly reduce the interference at the primary receiver compared to the zero forcing beamforming as well as joint leakage suppression method and thereby decreases the outage probability. This beamforming method is further extended for the case when the channels between the primary receiver and the CR relays are not known perfectly. Moreover, in this paper, we propose and investigate two relay selection strategies in conjunction with cooperative beamforming. The presented numerical results show that the relay selection schemes in conjunction with the cooperative beamforming method can further improve the received signal power at the secondary destination.

Is balloon osteoplasty attractive or questionable treatment for Hill-Sachs lesion?

Dear Editor, We have read the article “Balloon osteoplasty—a new technique for minimally invasive reduction and stabilisation of Hill-Sachs lesions of the humeral head: a cadaver study” by Sandmann et al. [1] with great interest. Hill-Sachs lesion treatment is very difficult regarding its widespread approaches. Too many treatment protocols can be found in current literature with different success rates. The balloon-osteoplasty technique may be seen as attractive, but we have many questions to the authors about this technique. We use balloon osteoplasty for fresh spinal compression fracture. If compression healed with fibrosis, balloon strength is not sufficient for restoration. Short tau inversion recovery (STIR) sequence is very sensitive for detecting vertebral oedema following fresh fractures or micro-fractures [2]. This study was performed on cadaveric bone and all fractures created manually and were therefore fresh. This is not the case with old Hill-Sachs fractures, which is why it is not so easy to restore height in Hill-Sachs lesions. Violatin might cause joint fracture and leakage to occur into the joint space. Is this technique effective for all kinds of Hill-Sachs lesions? Other technical complications from the inappropriate placement of instruments during balloon osteoplasty have resulted in a breach of the joint and inadvertent leakage of cement into the spinal canal. Your instruments were modified; thus, is the entrance point the same for all patients? And is one modified instrument sufficient for all kinds of Hill-Sachs lesions? What is the time of exposure to radiation? Is the modified instrument cost high? What is the ideal amount of augmentation necessary to restore a desirable degree of local strength and stiffness?

Failure analysis on weld joints between the elbow and straight pipes of a vacuum evaporator outlet

This study presents an analysis on a weld joint leakage accident between elbow and straight pipes that connect the inlet of a catalyst plant vacuum pump and the outlet of a vacuum evaporator tank. Moreover, the causes and mechanisms of material degradation are investigated by analyzing the chemical compositions and observing the microstructures with the use of a metallographic microscope and a scanning electron microscope. Energy dispersive spectroscopy was used on the test materials and corrosion products to examine the changes in the elements during material degradation. The results show that stress corrosion cracking caused the cracks and the leakage on the joints. The fracture morphologies were dominated by river cleavage and fan-shaped cleavage patterns. The existence of Cl− and residual stress from the installation of the elbow pipe and the heat effect of the welding process contributed to the stress corrosion cracking.

Inversion of pressure anomaly data for detecting leakage at geologic carbon sequestration sites

Leakage from abandoned wells and geologic faults represents one of the greatest risks to the integrity of geologic CO2 sequestration sites. The ability to detect leakage in a timely manner is, therefore, crucial for mitigating the potential adverse impacts of leakage to the public and environment. We present an inversion approach for recovering both leakage locations and rates by using observed pressure anomaly data. The approach is based on formulation of a linear system of equations using the unit-step response method, which is applicable to both analytical and numerical models. Because the resulting system is often ill conditioned, we investigate the efficacy of regularization methods for stabilizing the solutions. Further, when prior information is insufficient to restrict the number of search locations, a global optimization algorithm is used to solve the challenging problem of joint location and leakage history inversion. The performance of several linear inversion solvers is compared while considering effects such as measurement error and spatial heterogeneity. The results are promising and suggest that our pressure-anomaly-based leakage detection algorithm can be used to identify leaky wells in practice. It can be deployed as an integrated component of CO2 risk management frameworks.

Adjacent box girders without internal diaphragms or post-tensioned joints

In this paper, two non-posttensioned transverse connections are proposed for use in precast, prestressed concrete adjacent box-girder bridges. The proposed continuous connections are designed to transfer transverse shear and moment between adjacent boxes, eliminating the need for intermediate diaphragms. These connections are based on monolithic emulation of a multicell cast-in-place box-girder superstructure. The wide-joint connection consists of top and bottom reinforcement and a wide full-depth shear key filled with flowable concrete. The narrow-joint connection consists of full-depth grouted shear keys and top and bottom couplers. Design charts for different bridge configurations were developed using finite element models. Fatigue and monotonic load testing were performed on the proposed connections and one commonly used connection to evaluate their joint leakage, fatigue capacity, and ultimate capacity. Results indicate that the proposed connections outperform the current connection. The findings from this study indicate that the proposed connection could simplify box production, increase construction speed, and reduce construction cost.

Effect of Separating Load Eccentricity on the Clamp Load Loss in a Bolted Joint Using a Strain Hardening Model

Abstract A nonlinear model is proposed for studying the effect of the eccentricity of applied tensile forces on the clamp load loss in bolted joints that were initially tightened beyond the bolt elastic limit while the joint remained in the elastic range. A closed form solution is obtained for the amount of clamp load loss due to a cyclic separating force. The proposed model takes into account two sources of nonlinearity, namely, the strain hardening behavior of the yielded bolt material as well as the nonlinear deformation behavior of the clamped plates under an external separating load. After the initial tightening of the fastener past its elastic limit, the subsequent application of a tensile separating force on the joint tends to increase the fastener tension in a nonlinear fashion, and, simultaneously, reduce the clamping force in the bolted joint from its initial value. Upon the removal of the cyclic tensile load, the bolted joint system reaches a new equilibrium point between the residual fastener tension and the joint clamping force. At the new equilibrium point, the fastener tension is reduced from its preload due to its plastic elongation; simultaneously, a partial yet permanent loss in the clamp load level takes place. Excessive clamp load loss may lead to joint leakage, fastener loosening, or fatigue failure. For a known amplitude of the external cyclic tensile load, the increase in bolt tension and corresponding reduction in the joint clamp load are highly sensitive to the eccentricity of the tensile load (from the bolt center). Variables studied include the eccentricity value of the separating load, rate of strain hardening of the bolt material, compressive and tensile stiffness of the clamped plates, bolt stiffness, bolt preload, and magnitude of the separating tensile load.

Assembling Knowledge

This article highlights various topics covered in ASME Standard and Certification’s Guidelines for Pressure Boundary Bolted Joint Assembly. This major revision focuses on significant additions to capture proven assembly knowledge, which impacts safety, efficiency, best practice, and cost reduction. In addition, the revision recommends that gaskets be not reused. This inclusion was made based on field experience with joint leakage or flange facing damage where gaskets, in particular RTJ gaskets, are reused. Appendix P provides guidance and a series of checklists designed to guide the user through an investigation of joint leakage. ASME PCC-1-2010 represents a step change in the level of detail provided for guidance on bolted joint assembly and will represent a significant body of work for the international improvement of the integrity of bolted flanged joints. The undertaking and commitment by the subcommittee members was significant; however, it is believed that the benefit to industry from this revision will be commensurate.

Analysis of Bolt Joint Using the Finite Element Method

Analysis of Bolt Joint Using the Finite Element Method A numerical analysis of the initially clamped bolt joint subject to the working pressure is presented in the paper. Special, hexahedral 21- and 28-node isoparametric finite elements have been employed to model the contact zone. In this model, one takes into account loading due to the working pressure in the gap between the gasket and the flange arising as an effect of the progressing joint opening, what has not been considered in recent papers. Nonlinear stiffness characteristics of the bolt and the flange with the gasket are developed. Working pressure corresponding to the critical bolt force resulting in the joint leakage (complete opening between the gasket and the flange) is determined. FE computational results are compared with the available experimental results. The numerical results are presented using the authors' own graphical postprocessor.

Development of samarium [ 32P] phosphate colloid for radiosynoviorthesis applications: Preparation, biological and preliminary clinical studies experience

A new therapeutic radio colloid for radiosynoviorthesis (RS) applications is reported. The method of preparation involves the reaction of SmCl 3 carrier with carrier added [ 32P]H 3PO 4 in the presence of gelatin. The pure colloid was recovered by dialysis purification leading to radiochemical yield of around 90%. The radiochemical purity of the pure colloid formulated in isotonic saline was over 98%, for the usage period of 14 days, as assessed by paper chromatography. Ninety percent of colloid particles were in the size of 1–10 μm as evident from the laser diffraction particle size analysis, ideally suitable for the intended end use. Animal studies revealed complete retention of the radio colloid in the rabbit knee joint. The results of clinical trials in humans are satisfactory and encouraging, satisfactory retention of the colloid in the knee joint and negligible leakage into the systemic circulation.

Intra-articular injection of hyaluronate and indomethacin in rabbits with antigen-induced arthritis

Combined effects of hyaluronate and indomethacin in the treatment of rabbits with antigen-induced arthritis (AIA) were evaluated by assessing joint swelling, C-reactive protein (CRP) and prostaglandin E(2) (PGE(2)) levels with periodic intra-articular (ia) injections of hyaluronate alone (HA group) and with either a low or high concentration of indomethacin (LI-HA or HI-HA group). End-point analyses included matrix metalloproteinases-3 (MMP-3) activity and macroscopic and histological joint examinations. Results demonstrated that treatment in LI-HA and HI-HA groups resulted in statistically significant suppression of CRP, PGE(2, )and MMP-3 in comparison with those of HA group. Inhibition of serum CRP was only observed in LI-HA group. The order of serum MMP-3 inhibition was LI-HA>HI-HA>HA. Based on macroscopic and histological analyses of pannus formation, hyperplasia, inflammation, joint leakage and erosion, and loss of proteoglycan, the only statistically significant improvement was shown in LI-HA group compared to HA group and HI-HA group compared to control group.

Nonlinear Strain Hardening Model for Predicting Clamp Load Loss in Bolted Joints

Abstract Closed form solution for the amount of clamp load loss due to an externally applied separating force is determined for a bolted assembly in which the fastener is initially tightened beyond its proportional limit. The joint may or may not have been yielded at initial assembly, however. After the initial tightening of the fastener, the joint is subsequently subjected to a tensile separating force, which further increases the fastener tensile stress into the nonlinear range. Such a separating force will simultaneously reduce the clamping force in the bolted joint. Upon the removal of the separating service load, the bolted joint system reaches a new equilibrium point between the fastener tension and the joint clamping force. At the new equilibrium point, the fastener tension is reduced from its value at initial assembly, due to the plastic elongation of the fastener. The reduction in fastener tension translates into a partial—yet permanent—loss of the clamping load, which may lead to joint leakage, loosening, or fatigue failure. A nonlinear strain hardening model is implemented in order to describe the fastener behavior past the proportional limit of its material, and to determine the clamp load loss due to the permanent set in the fastener after the separating force has been removed. In order to study the effect of strain hardening, various rates of strain hardening are used for modeling the behavior of the fastener material. The effect of three nondimensional variables on the amount of clamp load loss is investigated. This includes the joint-to-fastener stiffness ratio, the ratio of initial fastener tension to its elastic limit, and the ratio of the separating force to its maximum value that would cause joint separation to start. Analytical results are presented for a range of stiffness ratios that simulates both soft and hard joint applications.

Clamp Load Loss due to Fastener Elongation Beyond its Elastic Limit

The amount of clamp load due to an externally applied separating force is determined for a boiled assembly in which the fastener is elongated past its proportional limit, while the clamped joint remained within its elastic range. After the initial tightening of the fastener, the joint is subsequently subjected to a tensile separating force, which further increases the fastener tensile stress into the nonlinear range. Such separating force will simultaneously reduce the clamping force in the bolted joint. Upon the removal of the separating service load, the bolted joint system reaches a new equilibrium point between the fastener tension and the joint clamping force. At the new equilibrium point, the fastener tension is reduced from its value at initial assembly, due to the plastic elongation of the fastener. The reduction in fastener tension translates into a partial—yet permanent—loss of the clamping load that may lead to joint leakage, loosening, or fatigue failure. A nonlinear model is established in order to describe the fastener behavior past the proportional limit of its material, and to determine the clamp load loss due to the permanent set in the fastener after the separating force has been removed. Two fastener materials with significantly different rates of strain hardening are used for modeling the behavior of the bolted joint system. The effect of three nondimensional variables on the amount of clamp load loss is investigated. The first variable is the stiffness ratio of the joint and the fastener. The second is the ratio of initial fastener tension to the fastener elastic limit, and the third variable is the ratio of the separating force to the force that causes joint separation to start. Analytical results are presented for a range of stiffness ratios that simulates both soft and hard joint applications. Experimental verification of the analytical results is presented.

耳かき外傷によるアブミ骨底板骨折例

A case of fracture of the stapes footplate with ossicular disruption and perilymph fistula caused by earpick-induced trauma is reported. A 51-year-old female was presented with hearing loss and vertigo just after sticking an ear pick into her left ear. Pure tone audiometry showed a mixed hearing loss of 67.5dB. Nystagmus was not observed, and vertigo improved in a week. On exploratory tympanotomy, the fracture of the stapes footplate accompanying a dislocation of the incudo-stapedial joint and perilymphatic leakage from the oval window were found. The perilymph fistula was sealed with temporal fascia, and ossicular chain continuity was reconstructed by type N tympanoplasty. After the operation, the cochlear and vestibular symptoms improved.

Radiosynovectomy's clinical applications and cost effectiveness: A review

It is apparent that from the work of the authors and many others, including the work of Rivard, Sledge, Zuckerman, among others, that radiosynovectomy has an important role to play in providing effective treatment of affected joints associated with rheumatoid arthritis and other forms of arthritis as well as the hemophiliac joint. The treatment offers relief from the effects of recurrent joint effusion with an approximately 60% to 66% favorable response and from recurrent hemarthrosis in the hemophiliac joint with an approximately 75% to 80% favorable response. The impact of providing radiosynovectomy as an alternative to surgical synovectomy is seen, where postoperative side effects such as joint stiffness are avoided, improved quality of life is repeatedly documented, and the cost savings in health care dollars, particularly evident in the hemophiliac joint in this relatively small population, are potentially enormous. With almost two million people in the United States suffering from rheumatoid arthritis, the potential savings in health care dollars is also enormous. As with any use of in vivo radiopharmaceuticals, the potential for radiation-induced damage exists. However, with a 25 plus year record of use, more optimally configured radiopharmaceuticals, and the addition of maneuvers to minimize potential joint leakage, the risk of radiation induced damage appears to be minimal. It appears as though radiosynovectomy is an effective as well as cost-effective alternative to surgical synovectomy and is becoming the procedure of choice particularly in the hemophiliac patient with recurrent hemarthrosis and synovitis who has failed medical therapy. It is also the procedure of choice in patients for whom surgery is contraindicated because of the presence of clotting factor inhibitors.

Analysis of Flange Joints Under External Loads

Flange joint leakage is one of the common maintenance problems in refineries and chemical plants. This paper studies the effect of external loads on the strength and leakage behavior of flanged joints. Finite element and analytical methods are compared, and the proposed method is compared with leakage data. The common “equivalent pressure” method is shown to be very conservative, and a method of evaluating external loads is recommended.

Bolted flanged joint leakage analysis with non-linear gasket behaviour

A model for the bolted flanged joint was developed; one which allows the evaluation of the gasket and bolt load by analyzing the equilibrium configuration. The sealing capability of the joint is checked when the load-leakage gasket correlation is known. A three-dimensional graphic analysis is discussed. An approximate formula is introduced to ascertain the flange ring rotation. Sample problems with non-linear gasket behaviour are considered.

Repair of TMI‐1 OTSG tube failures. Use of a kinetic tube‐expansion process to resesal tubes within the upper tube sheet provides a cost‐effective and relatively low‐expousure repair process

TMI-1 is a 776 MWe pressurized-water reactor having two vertical, straight tube-and-shell, once-through steam generators (OTSGs). Extensive eddy-current (E/C) examination of the OTSG tubes, eventually revealed that over 8000 tubes in each generator had crack indications. In OTSG ''A'', 82% of the indications and, in OTSG ''B'', 97% of the indications, were within 5.08 cm (2 in.) of the top of the upper tube sheets. The use of a kinetic tube-expansion process to reseal the TMI-1 OTSG tubes within the upper tube sheet provided a cost-effective and relatively low man-rem exposure repair process. OTSG repairs were completed in June 1983 and post repair testing confirmed essentially no joint leakage when tested with nitrogen at a differential pressure of 1.03 X 10/sup 6/ Pa (150 psi). (JMT)

The Effect of Casing Wear on the Burst Strength of Casing—Part 1: Joint Leakage

A theoretical analysis has been performed to determine the effects of wear on the burst strength of casing. Burst failure occurs either by a leakage at the casing joint or by rupturing of the casing wall. Joint leakage and the effect of casing wear on joint leakage are discussed in this paper. Rupturing of the casing wall is treated in a companion paper [1]. The results of the analysis presented in this paper show that, for practical purposes, joint leakage under internal pressure is unaffected by casing wear.

The Effect of Casing Wear on the Burst Strength of Casing—Part 2: Statistical Burst Strength of Worn and Unworn Casing Strings

A theoretical analysis has been performed to determine the effects of wear on the burst strength of casing. Burst occurs either by a leakage at the casing joint or by a rupturing of the casing wall. The statistical nature of rupturing of casing is presented in this paper; joint leakage is discussed in a companion paper[1]. A method is presented in this paper that calculates the probable burst strength and confidence limits given the statistical distribution of casing properties; this method may be used for both worn and unworn casing. Using a limited set of casing properties, the analysis shows that the API methods for determining burst resistance may result in burst values that have very low probabilities of failure. In addition, the data used show that considerable casing wear can be tolerated before there is a significant probability of rupturing the casing wall under API calculated burst pressures.