Structural Failure Rate Research Articles

Water pipe failure prediction and risk models: state-of-the-art review

This review paper presents the current state-of-the-art pertains to water pipe failure prediction and risk assessment, published in the last ten years (2009–2019). This paper has been motivated by the lack of comprehensive review articles that integrates water network failure and risk modeling. Some of the current practices reviewed the pipe condition and its failure. Others focused on the statistical prediction models, whereas the rest outlined failure prediction models of large diameter mains only. The mainstream of the current practice, highlighted in this paper characterizes the structural deterioration and failure rates using various statistical techniques, whereas the remainder of research covers a proliferation of machine learning and soft computing applications to forecast and model the pipeline risk of failure. The review offers descriptions of the models together with their proposed methodologies, algorithms and equations, contributions and drawbacks, comparisons and critiques, and types of data used to develop the models using the bibliographic review method. Finally, future work and research challenges are recommended to assist the civil engineering research community in setting a clear agenda for the upcoming research.

Research on Single-Phase Grounding Fault Location Technology

In view of the complex structure, large scale and high failure rate of distribution network, as well as many branch lines, large transition resistance, difficult to detect fault signals and difficult to locate accurately., A single-phase grounding fault location method based on single-terminal measurement for distribution network with multi-dominant transmission lines is proposed. This method can solve the problem of reliable monitoring of small current grounding fault through data processing and analysis of measuring units installed at substation equipment and line end, find grounding fault line in time, find fault point, and adopt corresponding treatment measures to block the impact scope of user branch line accident, restore the power supply of non-fault line as soon as possible, and reduce the outage time. Providing further reliable power supply fundamentally solves the problems of reliability and safety of power supply in distribution network. This method only needs to synchronously measure the voltage and current at each end of the line when the parameters of the line are known. The method is simple and the measurement accuracy is high. By locating the single-phase-to-ground fault of multi-dominant power lines, the results show that the method is correct and accurate.

Surgical Management of Irreparable Rotator Cuff Tears: What Works, What Does Not, and What Is Coming.

➤ The term functionally irreparable rotator cuff tear (FIRCT) is intended to capture patients who would experience failure of an attempted primary rotator cuff repair because of the extent of cuff muscle and tendon damage and other patient-related factors.➤ Debridement, biceps tenodesis, and/or partial repair of the torn rotator cuff may reduce pain and improve function for selected patients with a FIRCT.➤ Static soft-tissue restraints to abnormal glenohumeral head translation, such as implantation of an absorbable balloon in the subacromial space or superior capsular reconstruction (SCR), appear to reduce pain and improve function, although some have reported a relatively high structural failure rate with SCR.➤ When improvement of strength is the primary goal of treatment, tendon transfers provide a viable treatment alternative; most tendon transfers for management of a FIRCT are currently performed with arthroscopically assisted techniques.➤ Transfer of the lower portion of the trapezius has emerged as a successful alternative to transfer of the latissimus dorsi, whereas transfer of the latissimus dorsi to the lesser tuberosity is being explored as an alternative to transfer of the pectoralis major for functionally irreparable subscapularis tears.

Arthroscopic repair of isolated subscapularis tears: clinical outcome and structural integrity with a minimum follow-up of 4.6 years

After isolated subscapularis repair, improvement in shoulder function has been reported at short-term review. The purpose of this study was to determine whether arthroscopic subscapularis repair provides durable improvement in objective and subjective shoulder function with a low structural retear rate. All patients treated with arthroscopic repair of an isolated subscapularis tear between August 2003 and December 2012 with a minimum follow-up period of 4.6 years were identified from our database. A number of patients in our study cohort underwent a prior complete midterm assessment, which allowed a subgroup analysis to detect changes in structural integrity and corresponding function. Clinical and radiographic outcomes, including outcomes on conventional radiography and magnetic resonance imaging or ultrasound, were assessed. The study enrolled 36 shoulders with a mean patient age of 57.7 years (range, 31-75 years; standard deviation, 10.6 years). The mean follow-up period was 8.6 years (range, 4.6-13.9 years; standard deviation, 2.44 years). Internal rotation to the thoracic vertebrae was achieved in 94% of cases and was significantly improved (P < .001) compared with the preoperativesituation. The mean relative Constant score improved from 68% preoperatively to 93% at final follow-up (P < .001). Magnetic resonance imaging evaluation showed a rerupture rate of 2.7% (1 of 36 shoulders). Twenty patients underwent previous complete midterm assessment (mean, 2.9 years; range, 1-4.5 years), with comparisons between midterm and long-term follow-up showing comparable results without statistically significant deterioration. Functional and subjective improvements in shoulder function are maintained at a mean follow-up of more than 8 years after isolated subscapularis repair and are associated with a low structural failure rate of the repair.

A New Probabilistic Framework for Structural System Fragility and Sensitivity Analysis of Concrete Gravity Dams

Concrete gravity dams are widely constructed owing to their advantages of low maintenance cost and relatively low risk of sudden failure. However, the structural failure rate has been reported to be higher than other dam types. Although various studies have been conducted to assess the structural fragility of concrete gravity dams, not enough emphasis was placed on system-level fragility and sensitivity analyses, which provide crucial information for mitigating dam failure. This study proposes a new probabilistic framework for system fragility and sensitivity analysis by employing a finite element model for concrete gravity dams. The proposed framework consists of four steps, namely, structural analysis modeling considering the realistic loading conditions, component fragility analysis employing finite element reliability analysis, system fragility analysis employing system reliability analysis, and system sensitivity analysis using the finite difference method, which require several numerical algorithms and computational techniques. The proposed framework is applied to a numerical example of a typical concrete gravity dam in South Korea, and the analysis is completed successfully. As a result, the example dam is found to be relatively more vulnerable to sliding and concrete overstress than ground overstress. In addition, it is revealed that the dam system is more likely to fail in the overflow part than in the non-overflow part. The most critical factor in preventing these failures is the concrete mass density, followed by the silt mass density and the concrete compressive strength. Based on these analysis results, it is confirmed that the proposed framework provides valuable information for risk-informed structural design and failure mitigation of concrete gravity dams.

The main influencing factors of soil mechanical characteristics of the gravity erosion environment in the dry-hot valley of Jinsha river

AbstractThe dry-hot valley region counts as one of the most eco-sensitive zones in China, the issue of soil erosion is critical in regional ecological environment, soil mechanical property is one of the primary factors confining the occurrence of erosion, and it is attached crucial significance to in ascertaining the characteristics and principal factors of soil mechanics, and how to prevent and control soil erosion in arid red soil area of dry-hot valley. Through monitoring field location and directly shearing, the soil mechanical characteristics and the primary influencing factors of the mass erosion environment in the basin were ascertained. As the result indicates: (1) The soil moisture content, cohesion and internal friction angle are evidently correlated with each other abiding by power function, the relationship among soil cohesion, internal friction angle and volume moisture content goes as:$$\begin{array}{} \displaystyle c=80.107e^{-5.451\frac{{\it\omega}}{1.64\,+\,{\it\omega}}},\phi=65.646{\rm e}^{-3.325\frac{\omega}{1.64\,+\,\omega}}; \end{array}$$(2) The soil being large in pore radius vary in number and distribution evidently with structure and destruction degree (P&lt;0.05). Soil aggregation was also significantly different (P&lt;0.05), with the increasing of structural failure rate, the shear strength of soil decreased, and the probability of damage was increased as the external load increaseing. (3) The disintegration of soil can be effectively decelerated, and anti-disintegration ability of soil can be enhanced by the root system. The impact exerted by plant root system on shear strength of soil decreased as soil got deeper, more than a certain depth can be ignored; the impact exerted by plant root system on small-scale gravitational erosion was particularly evident, whereas the impact exerted by large-scale mass erosion was comparatively small. The ability of plant roots to optimize soil resistance was primarily through the roots shorter than 2 mm, the effective fibrous roots in the soil of the Leucaena Benth and the Dodonaea angustifolia were comparatively small, and the root of the herbaceous plants was comparatively large.

Effect of different vegetation restoration types on fundamental parameters, structural characteristics and the soil quality index of artificial soil

Outside soil spray seeding (OSSS), the technology of spraying an artificial soil mixture onto the surface of cut slopes for creating a bed for plant species to germinate and grow, has been widely used to restore cut slopes. The vegetation cover can effectively resist soil erosion, improve soil quality and facilitate the ecological restoration of cut slopes. However, researchers have different views on what kind of vegetation cover is best to improve artificial soil quality and enhance the structural stability of cut slopes. To evaluate the effect of different vegetation restoration types on the artificial soil of cut slopes restored with OSSS, various soil samples were obtained from four treatments [herbaceous-only vegetation restoration slopes (HS); mixed vegetation restoration type slope I, composed of herbs and shrubs (MSI); mixed vegetation restoration type slope II, composed of herbs, shrubs and trees (MSII); and natural slopes (NS)]. Three slopes were selected for HS, MSI, MSII and NS, respectively, for a total of twelve slopes. The soil properties measured included some fundamental parameters (physical, chemical and biological parameters) and structural characteristics (bias coefficients, peak convex coefficient, fractal dimension, structural failure rate and soil erodibility). Principal component analysis (PCA) and ascending and descending functions were used to determine an integrated soil quality index (SQI). The results showed that there are significant differences in fundamental parameters, structural characteristics and the SQI between HS and other treatments, while the same properties, except SQI, were not significantly different between MSI and MSII. These findings imply that the HS is not suitable for long-term restoration on cut slopes, whereas MSII is a better vegetation construction model for the ecological restoration of cut slopes. However, there is still a huge disparity in these soil properties between the cut slopes and NS; this difference is attributable to the NS having a soil optimization process with long-term no human interference. Therefore, more effective management measures should be implemented to promote the ecological restoration of cut slopes.

Current concepts in the primary management of irreparable posterosuperior rotator cuff tears without arthritis.

Various procedures exist for patients with irreparable posterosuperior rotator cuff tears (IRCT). At present, no single surgical option has demonstrated clinical superiority.There is no panacea for treatment and patients must be aware, in cases of palliative or non-prosthetic options, of an alarming rate of structural failure (around 50%) in the short term.The current review does not support the initial use of complex and expensive techniques in the management of posterosuperior IRCT.Further prospective and comparative studies with large cohort populations and long-term follow-up are necessary to establish effectiveness of expensive or complicated procedures such as superior capsular reconstruction (SCR), subacromial spacers or biological augmentation as reliable and useful alternative treatments for IRCT.Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.180002

An Update on Scaffold Devices for Rotator Cuff Repair

The annual volume of rotator cuff repairs in the United States is roughly 250,000, and failure rates still range from 20% to 70% in most studies despite significant advances in surgical technique and rehabilitation protocols. Even many “healed” repairs continue to have pain, weakness, and dysfunction, a phenomenon that may be explained by “Failure with continuity,” where the healing tendon retracts from the repaired location without a structural defect, leaving interposed scar tissue. To improve clinical outcomes, there is a need to minimize the rate of structural failure and minimize the failure with continuity that occurs after rotator cuff repair. Scaffold devices, in the form of extracellular matrix or synthetic grafts, hold promise in their abilities to mechanically and/or biologically augment repair sites. However, these devices can be technically challenging to apply, and the surgeon must be proficient in their use. To justify the increased operative time and cost associated with their use, we must also demonstrate the ability of these devices to improve structural and clinical outcomes.

The texture, structure and nutrient availability of artificial soil on cut slopes restored with OSSS – Influence of restoration time

Outside soil spray seeding (OSSS) is widely used to restore cut slopes in southwest of China, and artificial soil is often sprayed onto cut slopes to establish a soil layer for revegetation. The stability of artificial soil layer and its supply of water and nutrients for plants is crucial for successful restoration. To evaluate the long-term effectiveness of OSSS, the texture, structure and nutrient availability of artificial soil were studied, various soil samples were obtained from three cut slopes with different restoration time (restored with OSSS in 1996, 2003 and 2007 respectively) and one natural developed slope (NS). The properties measured including soil particle size distribution (PSD), texture, fractal dimension of PSD (Dm), the bias (CS) and peak convex (CE) coefficients of aggregate size distribution, structure failure rate, bulk density, moisture, pH, soil organic carbon (SOC), calcium carbonate content, Available nitrogen (NA), Available phosphorus (PA), and Available potassium (KA). The results showed that different restoration time resulted in significant differences in soil PSD, Dm, CS, CE, structure failure rate, bulk density, moisture, pH, NA, and KA. And these properties improved with increasing restoration age. However, there is still a huge disparity in soil texture, structure, and the availability of nutrients and moisture between the cut slopes and NS over a restoration period of up to 17 years, and this is caused by the little fine particles and the lack of slow release fertilizers and organic fertilizers in the artificial soil, resulting in poorer soil structure stability, retention and availability of moisture and nutrients on the cut slopes. Overall, the OSSS technique shows a long-term effectiveness in southwest of China, but there is still room for improvement.

Nationwide Longitudinal Follow-Up ofRiata Leads Under Advisory at 3AnnualScreenings: Report From the Netherlands Heart Rhythm Association DeviceAdvisory Committee.

This study sought to determine prospectively the rate of conductor externalization (CE), and whether this was associated with electrical failure. The Riata family of defibrillator leads was placed under U.S. Food and Drug Administration advisory as of November 28, 2011 because of high rates of CE. A nationwide cohort established in 2012 of 1,029 patients with recalled Riata leads with 147 CE were followed until death, lead discontinuation, or 3 annual screenings with fluoroscopy and device interrogation. Follow-up of 882 patients with normal baseline fluoroscopy revealed incident overt CE in 95 leads (11%) after median risk time of 2.9 years, yielding an incidence rate of 4.9 (95% confidence interval [CI]: 3.9 to 5.9) per 100 patient-years. The incidence rate was significantly higher in 8-F Riata leads than in 7-F Riata ST leads (7.0 vs. 3.2 per 100 patient-years; p< 0.001). Electrical follow-up demonstrated electrical abnormality in 77 leads, resulting in an incidence rate of 4.0 (95% CI: 3.2 to 5.0) per 100 patient-years. The incidence rate of electrical abnormalities was not different between leads without CE and those with CE (3.9 vs. 5.2 per 100 patient-years; p= 0.39). The development of CE is progressive in nature with an incidence rate of new CE of 4.9 per 100 patient-years, with a higher rate for 8-F Riata leads than for 7-F Riata ST leads. Despite the high rate of structural failure, no association between development of CE and electrical failure was observed.

The Impact of Re-tear on the Clinical Outcome after Rotator Cuff Repair Using Open or Arthroscopic Techniques - A Systematic Review.

Background:It is generally accepted that rotator cuff repair gives satisfactory results in the long term, although most studies have so far shown a fairly high rate of structural failure or re-tear. The purpose of this review study is to assess whether failure of the repaired cuff to heal could negatively affect the functional outcome.Methods:This article includes an extensive Internet PubMed based research in the current English-language literature including level I to level V studies as well as systematic reviews.Results:According to this extended study research, the results are mixed; certain reports show that patients with a healed rotator cuff repair have improved function and strength compared to those with structural failure, whereas other studies support the generally perceived concept that tendon re-tear does not lead to inferior clinical outcome.Conclusion:Further high-level prospective studies with larger numbers of patients and longer follow up are needed to overcome the current debate over function between healed and failed rotator cuff repairs.

Compression tests of Fusarium graminearum ascocarps provide insights into the strength of the perithecial wall and the quantity of ascospores

The plant pathogenic ascomycete Fusarium graminearum produces perithecia on corn and small grain residues. These perithecia forcibly discharge ascospores into the atmosphere. Little is known about the relationship among the strength of the perithecial wall, the age of the perithecium, and the quantity of ascospores produced. We used a mechanical compression testing instrument to examine the structural failure rate of perithecial walls from three different strains of F. graminearum (two wild type strains, and a mutant strain unable to produce asci). The force required to compress a perithecium by one micrometer (the mean perithecium compression constant, MPCC) was used to determine the strength of the perithecial wall. Over the course of perithecial maturation (5–12days after the initiation of perithecial development), the MPCC was compared to the number of ascospores contained inside the perithecia. The MPCC increased as perithecia matured, from 0.06Nμm−1 at 5d to 0.12Nμm−1 at 12d. The highest number of ascospores was found in older perithecia (12d). The results indicated that for every additional day of perithecial aging, the perithecia become more resilient to compression forces. Every additional day of perithecial aging resulted in ∼900 more ascospores. Knowledge of how perithecia respond to external forces may provide insight into the development of ascospores and the accumulation of turgor pressure. In the future, compression testing may provide a unique method of determining perithecial age in the field, which could extend to management practices that are informed by knowledge of ascospore release and dispersal.

Massive Rotator Cuff Repair With All-Arthroscopic Patch Augmentation: A Surgical Technique

Surgical management of massive rotator cuff tears is plagued by structural failure rates as high as 94%. Multiple arthroscopic and open techniques have been described, but there is no current gold standard. Biological healing at the tendon footprint is key to avoiding failure. Xenograft patch placement has been described as a possible technique to augment the biology of rotator cuff repair when tendon quality is compromised. The purpose of this article is to describe an all-arthroscopic technique of patch augmentation for repair of massive rotator cuff tears.

Platelet-rich Plasma in the Management of Arthroscopic Rotator Cuff Repair: Update 2016

Arthroscopic rotator cuff repair has shown a high rate of patient satisfaction. Multiple studies, however, have shown significant structural failure rates. Platelet-rich plasma seemed to be a safe, reasonable way to provide growth factors to improve these rates of healing. While preliminary results were encouraging, higher-level studies with longer-term follow-up have not borne out the early enthusiasm for the use of platelet-rich plasma. The reason for this failure is multifactorial, and includes differences in products as prepared, variations in growth factor concentrations both between patients and even day to day in the same patient. Timing and technique of application also remain to be resolved. Although complications have been minimal, the lack of long-term benefit and cost of the material indicate that this material cannot be recommended in its current preparations.

The physico-chemical properties and structural characteristics of artificial soil for cut slope restoration in Southwestern China.

Cut slopes are frequently generated by construction work in hilly areas, and artificial soil is often sprayed onto them to promote ecological rehabilitation. The artificial soil properties are very important for effective management of the slopes. This paper uses fractal and moment methods to characterize soil particle size distribution (PSD) and aggregates composition. The fractal dimension (D) showed linear relationships between clay, silt, and sand contents, with coefficients of determination from 0.843 to 0.875, suggesting that using of D to evaluate the PSD of artificial soils is reasonable. The bias (CS) and peak convex (CE) coefficients showed significant correlations with structure failure rate, moisture content, and total porosity, which validated the moment method to quantitatively describe soil structure. Railway slope (RS) soil has lower organic carbon and soil moisture, and higher pH than natural slope soil. Overall, RS exhibited poor soil structure and physicochemical properties, increasing the risk of soil erosion. Hence, more effective management measures should be adopted to promote the restoration of cut slopes.

High volume hydraulic fracturing operations: potential impacts on surface water and human health

High volume, hydraulic fracturing (HVHF) processes, used to extract natural gas and oil from underground shale deposits, pose many potential hazards to the environment and human health. HVHF can negatively affect the environment by contaminating soil, water, and air matrices with potential pollutants. Due to the relatively novel nature of the process, hazards to surface waters and human health are not well known. The purpose of this article is to link the impacts of HVHF operations on surface water integrity, with human health consequences. Surface water contamination risks include: increased structural failure rates of unconventional wells, issues with wastewater treatment, and accidental discharge of contaminated fluids. Human health risks associated with exposure to surface water contaminated with HVHF chemicals include increased cancer risk and turbidity of water, leading to increased pathogen survival time. Future research should focus on modeling contamination spread throughout the environment, and minimizing occupational exposure to harmful chemicals.

Arthroscopic rotator cuff repair in the weight-bearing shoulder

In wheelchair-dependent individuals, pain often develops because of rotator cuff tendon failure and/or osteoarthritis of the glenohumeral joint. The purposes of this study were to investigate (1) specific rotator cuff tear patterns, (2) structural healing, and (3) clinical outcomes after arthroscopic rotator cuff repair in a cohort of wheelchair-dependent patients. Forty-six shoulders with a mean follow-up of 46 months (range, 24-82 months; SD, 13 months) from a consecutive series of 61 shoulders in 56 patients (46 men and 10 women) undergoing arthroscopic rotator cuff repair were available for analysis. Clinical outcome analysis was performed using the Constant-Murley score, the Subjective Shoulder Value, and the American Shoulder and Elbow Surgeons score. The integrity of the repair was analyzed by ultrasound. Of the shoulders, 87% had supraspinatus involvement, 70% had subscapularis involvement, and 57% had an anterosuperior lesion involving both the supraspinatus and subscapularis. Despite an overall structural failure rate of 33%, the patients showed improvements in the Constant-Murley score from 50 points (range, 22-86 points; SD, 16 points) preoperatively to 80 points (range, 40-98 points; SD, 12 points) postoperatively and in the American Shoulder and Elbow Surgeons score from 56 points (range, 20-92 points; SD, 20 points) preoperatively to 92 points (range, 53-100 points; SD, 10 points) postoperatively, with a mean postoperative Subjective Shoulder Value of 84% (range, 25%-100%; SD, 17%). Failure of the rotator cuff in weight-bearing shoulders occurs primarily anterosuperiorly. Arthroscopic rotator cuff repair leads to a structural failure rate of 33% but satisfactory functional results with high patient satisfaction at midterm follow-up.

CREDO: Electrical and Structural Failure Rates of Endocardial Leads

CREDO: Electrical and Structural Failure Rates of Endocardial Leads

Wood placement in river restoration: fact, fiction, and future direction

Despite decades of research on wood in rivers, the addition of wood as a river restoration technique remains controversial. We reviewed the literature on natural and placed wood to shed light on areas of continued debate. Research on river ecology demonstrates that large woody debris has always been a natural part of most rivers systems. Although a few studies have reported high structural failure rates (&gt;50%) of placed instream wood structures, most studies have shown relatively low failure rates (&lt;20%) and that placed wood remains stable for several years, though long-term evaluations of placed wood are rare. The vast majority of studies on wood placement have reported improvements in physical habitat (e.g., increased pool frequency, cover, habitat diversity). Studies that have not reported improvements in physical habitat often found that watershed processes (e.g., sediment, hydrology, water quality) had not been addressed. Finally, most evaluations of fish response to wood placement have shown positive responses for salmonids, though few studies have looked at long-term watershed-scale responses or studied a wide range of species.