Academic literature on the topic 'Location-specific lifing'

AbstractThe present paper describes a probabilistic framework to predict the fatigue life and failure mode under various thermo-mechanical loading conditions. Specifically, inclusion- and matrix-driven competing failure modes are examined within nickel-based superalloys. The critical accumulated plastic strain energy density (APSED) is employed as a unified metric to predict fatigue crack initiation in metals, which is favorable due to the usage of a single unknown parameter and its capability to predict failure across loading conditions and failure modes. In this research, we characterize the temperature-dependent variation of the critical APSED using a Bayesian inference framework and predict the competing failure modes in a coarse grain variant of RR1000 with varying strain range and temperature. The critical APSED appears to decrease along a vertically reflected sigmoidal curve with increasing temperature. Further, (a) the prediction of a failure mode, (b) failure mode associated with the minimum life, and (c) the change in the location associated with the matrix-driven failure mode with increasing temperature and decreasing strain range are consistent with the experimentally observed trends in RR1000, as well as other Nickel-based superalloys, documented in the literature. Finally, for each simulated loading condition, the uncertainty in the fatigue life is quantified as a prediction interval computed based on a $$95\%$$ 95 % confidence level of the critical APSED and the computed APSED from simulations. The overall framework provides a promising step towards microstructural-based fatigue life determination of components and enables a location-specific lifing approach.

Borehole water intakes of underground water are widely used for water supply of agricultural towns, urban settlements, small and large cities and megacities. The number of consumers in these localities determines the number of water intakes, the number of wells, their productivity, location and connection to the prefabricated water conduits. Due to the increase in the use of underground water, the existing water intakes are being reconstructed and expanded. These works are accompanied by grouting of failed wells, their re-drilling, drilling of additional wells, re-laying of old and laying of new prefabricated water conduits. All this causes the complexity of the configuration of prefabricated water conduits due to the construction of jumpers and rings, the emergence of new wells with connection lines. Under the new conditions, in order to properly develop water intake operating modes which meet the minimum energy consumption for lifting and delivering a required volume of water to the collection-and-control tanks, to accurately choose the appropriate water lifting equipment in wells, to develop measures for intensifying water intake alongside with a forecast of their efficiency and to optimize the operation of the water intake, it is necessary to create its mathematical model that allows performing complex calculations. Water intakes with ramified prefabricated water conduits, as well as with an area scheme of the location of wells and a ring scheme of the connection of prefabricated water conduits are the most difficult object for mathematical modeling. The methods of calculating such water intakes are not sufficiently reflected in the literature, and there are no specific examples of calculation. The present article aims to clarify the methodology for calculating borehole water intakes with ramified prefabricated water conduits and with a ring scheme of their connection.

AbstractFlooding is routinely one of the most deadly weather-related hazards in the United States, which highlights the need for more hydrometeorological research related to forecasting these hazardous events. Building upon previous literature, a synergistic study analyzes hydrometeorological aspects of major urban flood events in the United States from 1977 through 2014 caused by locally heavy precipitation. Primary datasets include upper-air soundings and climatological precipitable water (PW) distributions. A major finding of this work is that major urban flood events are associated with extremely anomalous PW values, many of which exceeded the 99th percentile of the associated climatological dataset and all of which were greater than 150% of the climatological mean values. However, of the 40 cases examined in this study, only 15 had PW values that exceeded 50.4 mm (2 in.), illustrating the importance of including the location-specific PW climatology in a PW analysis relevant to the potential for flash floods. Additionally, these events revealed that, despite geographic location and time of year, most had a warm cloud depth of at least 6 km, which is defined here as the layer between the lifting condensation level and the height of the −10°C level. A “composite” flood sounding was also calculated and revealed a characteristically tropical structure, despite cases related to tropical cyclones being excluded from the study.

For tFor t For tFor the imaging advantages of aspheric optical component, it has been widely used in the aviation, aerospace, defense and civilian high-technology. Aspherical surface shape test is a key factor restricted aspheric processing and a complex sophisticated testing techniques. The well known measurement methods are faulty. Each method has advantages and disadvantages; many methods cannot be used for online testing. In this paper，the geometric principle of a swing-arm profilometer as a novel method to measure aspherics is introduced．The deviation between the actual and the ideal of aspherical surface shape is confirmed by the high-precision measurement for the vertical height with a specific path on the aspherical optical surfaces. By adjusting the location of measuring devices to maintain the distance of rotation center to the center of workpiece equal to the length of swing-arm,we can achieve the measurement for the workpiece of different machining tool. The measurement system mainly consists of the lifting and landing system of the high-precision axis,the high-precision level turntable rotary table, the high rigidity measuring arm and the high precision measurement sensors. And the follow-up data processing puts forward a number of error correction models at the same time. The advantages of the measurement method are that the measurement sports is only a simple turning motion .It will be helpful to reduce measurement errors and improve the efficiency of measurement.

It is known that a person who has suffered a spinal cord injury, in addition to sensitivity, locomotion, intestinal and urinary function impairment, regardless of the injury location, must also face sexual function impairment. Each person reacts differently, no matter how similar the injuries can be. The present study, which was an exploratory, descriptive, transversal, applied field study of quantitative nature, was carried out in three hospitals and two physical therapy clinics in the city of Ribeirao Preto, state of Sao Paulo, Brazil, with the objective of evaluating women with spinal cord injuries treated from January 1, 2000 to July 31, 2004. The study population consisted of 81 women. Thirty women were excluded as they did not meet the inclusion criteria: 12 of them had diagnoses that were not related to spinal cord injury, 11 could not be located, 6 died and one refused to participate in the study. Age range in which the spinal cord injury predominated was 18 to 37 years (38%). After the injury, 27% remained single, 28% remained with their partners; regarding the degree of schooling, Grade School predominated (49%) and 9% were illiterate. They presented traumatic etiology (100%) at the lumbar level (53%), followed by cervical (27%), thoracic (16%) and sacral (4%) levels. Of the external causes of the injury, car accident (29%) was the most prevalent, followed by falls (12%), firearm injury, weight lifting, being hit by a car, and motorcycle accident (8% each), shallow-water diving and being beaten up (2% each), and knife injury, sports activities, fall of object on the head, practicing radical sports and fall from one’s height added up to 16% of the women and among them, 94% are elderly. The “Changes in Sexual Functioning Questionnaire” (CSFQ) scale showed that 90% of the sample presented sexual dysfunction regarding the sexual pleasure variable, orgasm dysfunction (90%), desire/frequency dysfunction (76%), sexual interest dysfunction (72%) and arousal dysfunction (92%). This study confirmed that the patient with spinal cord injury presents specific complexities and particularities and that the scarcity of studies on the specific sexuality of women with spinal cord injuries does not offer a specific care that encompasses the social, psychological and physical dimensions, as well as the continuing homecare, establishing a rehabilitation process without quality.

Today, despite the progress made in dental implantology, the problem of rehabilitation of patients with significant bone atrophy in parodontal diseases has not been fully studied. The study aims to review the current views of various authors on the aetiology and treatment of parodontal diseases, which caused multiple tooth loss and bone atrophy in patients with occlusal pathology, based on the literature sources of scientific and medical information. Object and methods of study. Analytical study of scientific and medical literature on the treatment of multiple and partial tooth loss in patients with parodontal diseases in bone atrophy with impaired jaw relationships and orthopaedic rehabilitation using dental implantation and methods of bone augmentation of the mandible and maxilla. The use of implants in orthopaedic treatment expands the possibilities of using fixed prostheses, satisfying patients functionally and aesthetically. In case when the preservation of teeth becomes impossible or impractical to ensure proper treatment of the patient, they can be removed and replaced with dentures on dental implants. According to Misch C. [6], the masticatory load, which is exerted on the bone tissue of the jaws by an implant, increases the density of the bone structure. When teeth are lost due to parodontitis, there is atrophy of the alveolar ridge and a change in the structure of bone tissue, which is characterized by an increase in the porosity of the cancellous bone [4;5;7]. Sufficient bone volume and density in the area of the planned implantation are the main and important parameters for achieving normalized primary implant stabilization [11]. Partial and complete loss of teeth, as well as parodontal diseases, are always accompanied by the bone tissue of alveolar bone tissue of varying severity [1;4;5;13]. Signs of parodontal diseases in dentition defects are always more pronounced than in intact dental arch. The disease progresses rapidly, the dentition is destroyed if appropriate occlusal therapy is not performed [13;14]. Systemic factors and comorbidities in patients also play a significant role in reducing the bone volume of the jaws. The relationship between decreased bone density and age-related hormonal changes in women, as well as at the gender level, has been studied. Thus, women have changes in bone architecture and less dense arrangement of trabeculae in the jawbones than men [15].Bone tissue has a distinguishing feature – loss of multiple teeth or parodontal diseases lead to a redistribution of functional load, which causes its resorption [7;20]. In this regard, tooth extraction inevitably leads to a decrease in bone volume. The success of dental implantation on the maxilla became partially possible due to the introduction of sinus lifting with the use of osteoplastic materials [12;20;21]. According to some scientists[21], the autogenous bone graft is the gold standard in regenerative processes due to its osteoinductive, osteoconductive, and osteointegration properties, which are necessary for the restoration of lost bone tissue. The use of dentin in human teeth as an autograft was first described in a clinical case report in 2003 [23]. In recent experiments, these materials have proven to be a real alternative to the bone graft. Thanks to the work of a group of researchers [23;24], significant efforts were made in the basic and clinical study to find the best bone graft material for osseointegration of implants in the maxillary sinus. The autogenous dentin graft (AutoBT; Korea Tooth Bank, Seoul, Korea) was first developed in 2008, and several clinical studies have praised the use of AutoBT in the sinus compared to other grafts. Given the current development of advanced technologies in dental implantation, dentists use navigation templates in their practice, which are made using CAD CAM technology to improve the quality of care for patients who have indications for dental implantation. New diagnostic approaches allow us to virtually plan, simplify, and speed up surgery, to ensure accuracy. Thanks to this technology, dentists optimize the location of dental implants, taking into account the difficult conditions specific to patients with parodontal pathology.

Abstract Background Strengthening weakened ligament tissues with injectable fillers to improve their supportive effect may achieve the aesthetic goal of face lifting. Objectives The aim of our study was to design an injectable technique for enhancing the true facial ligaments and dissect the ligaments to provide anatomical guidance for effective injection. Methods Six true facial ligaments were chosen as target anatomical sites for injection. Specimens were dissected, and three-dimensional images were reconstructed to confirm the exact location of each injection site and to confirm that the proposed injection routes will not cause dangerous vascular damage. A total of five patients received the injections; three-dimensional images were taken before and after the injections for comparison and clinical outcome assessments. Results The injection technique was designed to target six true facial ligaments, as follows. Site 1 targeted the temporal ligamentous adhesion region to lift the lateral ends of the eyebrows. Site 2 targeted the region of the lateral orbital thickening to lift the lateral canthus. Site 3 and site 4 targeted the zygomatic retaining ligaments and zygomatic cutaneous ligaments, respectively, to augment the soft tissues of the midface. Site 5 targeted the region of the maxillary ligament to lessen the nasolabial folds, and site 6 targeted the mandibular ligament to reduce the marionette line. Conclusions This site-specific injection technique targeting the true ligaments may lead to increased efficiency and accuracy of face rejuvenation and exert a lifting effect.

Objective: Movement efficiency can be quantified during physical tasks by measuring the rate of change of acceleration (jerk). Jerk captures the smoothness of a motion and has been used to quantify movement for upper extremity and torso-based tasks. We collected triaxial accelerometer data during four physical tasks commonly performed in the work place to determine if jerk increases with physiologic strain.Methods: Participants completed a circuit of activities that mimicked the demands of manual labor in hot (40°C) and temperate (18°C) conditions. The circuit included walking on a treadmill carrying a load on the shoulder, lifting objects from the floor to the table, using a dead blow to strike the end of a heavy steel beam, and a kneeling rope pull. After the 9 min circuit, the participant had a standing rest for 1 min before repeating the circuit 3 additional times. Participants were instrumented with four 3-axis accelerometers (Actigraph wGT3X) secured to the torso, wrist, and upper arm.Results: There were 20 trials in the hot condition and 12 trials in the temperate condition. Heart rate and core body temperature increased during both protocols (p < 0.001). Measures of jerk varied by accelerometer location and activity. During treadmill walking, the wrist, torso, arm accelerometers measured higher jerk during the fourth circuit in the hot condition. During the lifting task, mean jerk increased in the hot condition in all accelerometers. Max jerk increased in the temperate condition in the arm accelerometer and jerk cost increased in the hot condition in the torso and arm accelerometers.Conclusions: Forty minutes of paced work performed in the heat resulted in increased acceleration and jerk in accelerometers placed on the torso, arm, and wrist. The accelerometers most consistently reporting these changes were task specific and suggest that a limited number of worn sensors could identify the onset of fatigue and increased injury risk.

Service lives for critical rotating parts in aero engine gas turbines are declared using deterministic lifing calculations based on fixed point values of key mechanical properties and factors to allow for the scatter. However, novel probabilistic lifing algorithms have been developed, which are able to take into account the degree of scatter in the material properties throughout the component. Process simulation software has been developed to predict the material flow, residual stresses, microstructure and properties in components during the disc forging operations to ensure robust manufacturing routes. This allows the changes in the materials microstructure, and the mechanical property variation throughout the component, to be predicted as the crack initiation and propagation properties are significantly dependent on the grain structure. These two strains of research have been combined in an attempt to increase the reliability of service life predictions through modelling the scatter in the mechanical properties resulting from manufacturing variation. Results will be presented which indicate that significant life benefits can be obtained by adopting a location specific lifing method based on this approach.

Abstract Modern industrial gas turbines must be capable of operational flexibility to fulfill the requirements of a changing power industry. At one extreme, turbines are required to run for extended periods of time at full load conditions to satisfy base load applications. At the other extreme, turbines are exposed to high cycles to satisfy peaking applications. Industrial gas turbine components that operate in the hot gas path are therefore subjected to loads that can lead to damage from both creep and fatigue. The traditional design approach is based on worst case operational scenarios. These worst case assumptions compound and typically result in a single damage mechanism and bounding location, which represents the minimum life of the turbine. In contrast, condition based assessments tend to consider multiple operating scenarios, which may result in different damage mechanisms and potentially different bounding locations. Condition based assessments of gas turbines therefore require sophisticated lifing routines that can identify these peak damage locations for a range of damage mechanisms and load states, to ensure reliability and availability of industrial gas turbines for flexible operation. Digital assets are a key element of modern condition based maintenance. However, a large fleet of diversely operated gas turbines results in an equally large number of digital assets. This produces specific challenges around data processing and storage of large machine datasets. Full order methods, such as Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) are traditional approaches to predicting temperatures and loads on key components in industrial gas turbines. These models are computationally expensive and are therefore suited to idealized engine cycles. However, digital assets are used to analyze actual operational data and therefore require Reduced Order Models (ROMs) to manage large data sets within a reasonable time frame for optimal asset management. Key to this is determining the bounding assessment locations. Structural integrity design codes provide a number of methods for assessing key damage mechanisms. This paper presents a comprehensive framework to use elements from these various codes to identify life limiting locations. This is a critical aspect of developing effective digital assets for condition based asset management. The approach provides a qualitative assessment of damage based on simple elastic finite analyses for typical engine load cycles. The method identifies locations with a high potential for the fundamental damage mechanisms including: creep, fatigue and oxidation and it allows for the assessment of elastic shakedown and ratcheting. Creep assessments in design codes typically consider only stress rupture. However, for cooled gas path components the stresses are both thermally and mechanically driven. The stress rupture approach is therefore insufficient to capture the full effects of creep and may misidentify key locations. The approach presented here addresses this shortfall by additionally considering creep strain due to stress relaxation, in addition to other damage mechanisms.

Abstract A multibody model of an electric go-kart was developed in Msc-Adams Car software to simulate the vehicle’s dynamic performance. In contrast to an ICE kart, its electric counterpart bares an extra weight load accounted for the batteries and other powertrain components. The model is inspired on a prototype vehicle developed at Universidad de los Andes. The prototype was built on top of an ICE frame where a PMAC motor, controller, battery pack and the subsequent powertrain components were installed. A petrol-based Go-kart weight distribution was defined as baseline and several variants of the electric adaptation with different weight distributions were constructed. The main objective of the model is to evaluate different configurations and identify the ones that can give performance advantages. Step steer simulations ran at 40 km/h (64 mph) were analyzed to assess the dynamic performance of the vehicle for different configuration of the battery bank placement. For most iterations of powertrain location, considerable differences in dynamic response were obtained and the handling balance was identified as Understeer contrary to a priori thoughs. Understeer gradient, weight distribution for both axles, trajectory among other results of interest were observed in the simulations. The model allowed to showcase the effect of redistribution of weight on the dynamic behavior in this specific application. Among the main consequences lies the fact that battery distribution can affect the lifting of the internal rear tire and the detriment in turning effectiveness.

Circulation control (CC) is a high-lift methodology that can be used on a variety of aerodynamic applications. This technology has been in the research and development phase for over sixty years primarily for fixed wing aircraft where the early models were referred to as “blown flaps”. Circulation control works by increasing the near surface velocity of the airflow over the leading edge and/or trailing edge of a lifting surface This phenomenon keeps the boundary layer jet attached to the wing surface thus increasing the lift generated on the surface. The circulation control airflow adds energy to the lift force through conventional airfoil lift production and by altering the circulation of stream lines around the airfoil. For this study, a 10:1 aspect ratio elliptical airfoil with a chord length of 11.8 inches and a span of 31.5 inches was inserted into the West Virginia University Closed Loop Wind Tunnel and was tested at varying wind speeds (80, 100, and 120 feet per second), angle of attack (zero to sixteen degrees), and blowing coefficients, ranging from 0.0006 to 0.0127 depending on plenum pressure. By comparing the non-circulation controlled wing with the active circulation control data, a trend was found as to the influence of circulation control on the stall characteristics of the wing for trailing edge active control. For this specific case, when the circulation control is in use on the 10:1 elliptical airfoil, the stall angle decreased, from eight degrees to six degrees, while providing a 70% increase in lift coefficient. It should be noted that due to the trailing edge location of the circulation control exit jet, a “virtual” camber is created with the free stream air adding length to the overall airfoil. Due to this phenomena, the actual stall angle measured increased from eight degrees on the un-augmented airfoil, to a maximum of twelve degrees.

Abstract Volumetric gas reservoirs are driven by the compressibility of gas and a formation rock, and the ultimate recovery factor is independent of the production rate but depends on the reservoir pressure. The gas saturation in the volumetric reservoir is constant, and the gas volume is reduced causing pressure drop in the reservoir. Due to this reason, it is crucial to minimize the abandonment pressure to the lowest possible level. Concerning Dnipro-Donetsk Basin (DDB) gas reservoirs, it is widespread to recover sometimes more than 90% of the OGIP. Often, OGIP was estimated not considering lower permeability gas layers due to inaccurate logging equipment used in the past, causing that such layers were not included in the total netpay. This is one of the reasons for OGIP overestimation and higher recovery factors. On many P/Z graphs, we observe that at certain drawdown, lower permeability reservoirs kick in lifting up P/Z plot curve. Abandonment pressure is a major factor in determining recovery efficiency. Permeability and skin are usually the most critical factors in determining the magnitude of the abandonment pressure. Reservoirs with low permeability will have higher abandonment pressures than reservoirs with high permeability. A specific minimum flow rate must be sustained to keep the well unloading process, and a higher permeability will permit this minimum flow rate at lower reservoir pressure. Abandonment pressure will depend on wellhead pressure, friction and hydrostatic pressures in the system, pressure drop in reservoir, and pressure drop due to skin. This last factor is often neglected, which sometimes leads to a significant reduction of the recovery factor. It is common practice that skin factor and pressure drop due to the skin are solved with well stimulation. Also, well stimulation has its limits concerning the level of reservoir pressure. It is very common that the stimulation effect of low reservoir pressure well is negligible or even negative. This is caused by the minimum required drawdown to flow back a stimulating aqueous fluid out of the reservoir. The required minimum drawdown is caused by the Phase Trapping Coefficient (PTC), which drives reservoir stimulation fluid cleaning behavior. For water drive gas reservoirs, Cole (1969) suggests that the recovery is substantially less than recovery from bounded gas reservoirs. As a rule of thumb, recovery from a water-drive reservoir will be approximately 50 to 75% of the initial gas in place. The structural location of producing wells and the degree of water coning are essential considerations in determining ultimate recovery. In the cases studied in this paper, we consider gas and rock expansion reservoir energy, if abandonment pressure needs to be coupled with a water drive, then it is recommended to use a numerical, not analytical approach.