Rehabilitation Techniques to Improve Long-Term Performances of Highway-Railway At-Grade Crossings

2011 ◽  
Author(s):  
Jerry G. Rose
Keyword(s):  
Smooth Surface ◽  
Unit Cost ◽  
Complete Removal ◽  
Layered System ◽  
Cooperative Effort ◽  
Railway Line ◽  
Railway Company ◽  
Railway Traffic ◽  
Long Life

The primary purpose of the highway-railway at-grade crossing is to provide a smooth surface for the safe passage of rubber-tired vehicles across the railroad. The crossing support and surface in the jointly used area represent a significantly expensive unit cost of the highway and railway line. The ideal highway crossing will maintain a smooth surface and stable trackbed for a long period of time. This will reduce costly, frequent disruptions to highway and railway traffic (to adjust the track or renew the surface due to rideability concerns), while concurrently providing improved operating performance and long life. Technology is available for rapidly renewing highway crossings within one day using a panel system with specifically designed layered support and premium materials. The procedure involves complete removal of the old crossing panel and trackbed materials — and replacing them with an asphalt underlayment layer, a pre-compacted ballast layer, a new track panel, and a new crossing surface. A cooperative effort between the local highway agency and the railway company will reduce costs, improve the quality of the finished product, and reduce outage of the highway and railroad. A major objective is to minimize disruption to both highway and railway traffic during the renewal process in addition to extending the life of the crossing. Suggested procedures, based on experiences for several installations, are presented. Typical schedules are for the railroad to be to be out-of-service for a maximum of four hours and for the highway to be closed only eight to twelve hours. Results are presented for crossings instrumented with pressure cells to document Pressure levels within the layered portion of the crossing structure. In addition, long-term Settlement measurements and assessments for several crossings are documented. The measurements indicate significantly reduced long-term settlements of crossings incorporating the rapid-renewal, layered system, while maintaining acceptable smoothness levels. These long-term performance evaluations indicate this practice ensures long-life, economical, smooth crossings for improved safety and operating performances for both highway agencies and railway companies.

Rehabilitation, Assessment and Management Practices to Ensure Long-Life, High Performance Highway-Railway At-Grade Crossings

2014 ◽  
Author(s):  
Brett Malloy ◽  
Jerry G. Rose ◽  
Reginald R. Souleyrette
Keyword(s):  
Decision Making ◽  
Smooth Surface ◽  
Performance Evaluations ◽  
Layered System ◽  
Decision Making Process ◽  
Railway Traffic ◽  
Long Life ◽  
Grade Crossings

Rehabilitating and/or replacement of highway-railway at-grade crossings frequently accounts for major track maintenance expenses for the U.S. highway governmental agencies and the railroad industry. Substantial numbers of crossings deteriorate at a more rapid rate than the abutting trackbed and pavement. This is largely due to the structural implications of the combined highway and railway loadings within the jointly used crossing area and difficultly in maintaining adequate drainage within the immediate crossing area. A highway-railway at-grade crossing is designed to fulfill its primary purpose of providing a smooth surface for the safe passage of rubber-tired vehicles across the railroad. The jointly used area represents a significantly expensive unit cost of the highway and railway line. Ideally a highway crossing will maintain a smooth surface and stable trackbed for a long period of time. This reduces costly and frequent disruptions to highway and railway traffic when the track needs adjusting or the surface needs replacing due to rideability concerns. Technology is available for “fast-tracking” the renewal of highway crossings within one day (if desired) using a panel system with specifically designed layered support and premium materials. The procedure involves complete removal of the old crossing panel and trackbed materials. The replacement consists of an asphalt underlayment layer, a pre-compacted ballast layer, a new track panel, and a new crossing surface. The composition of the asphalt layer is similar to that used for highways. It replaces all, or a portion of, the typical granular subballast layer. A cooperative effort between the local highway agency and the railway company will ideally reduce costs, improve the quality of the finished product, and reduce outage of the highway and railroad during the rehabilitation process. A major objective is to minimize disruption to both highway and railway traffic during the renewal process in addition to improving the performance and extending the life of the crossing. Typical schedules are for the railroad to be out-of-service for a maximum of four hours and for the highway to be closed only eight to twelve hours, when length of closure is an issue of importance. Numerous long-term tests and performance evaluations of heavy trafficked railway and highway crossings are presented herein. Pressure cells have been imbedded within the trackbed to document pressure levels within the layered portion of the crossing structure due to loadings from trains and highway vehicles. In addition, long-term settlement measurements and assessments for several crossings are documented. The measurements indicate significantly reduced long-term settlements of crossings incorporating the rapid-renewal, layered system, while maintaining acceptable smoothness levels. In addition, standard practices and specifications are presented for several highway agencies and railway companies using this technology for their crossing renewal programs. These long-term performance evaluations indicate this practice ensures long-life, economical, smooth crossings for improved safety and operating performances. The application of this technology continues to increase and it is considered a standard practice in many areas of the country. A crossing management technique (model decision-making process) is described for assessing the optimum engineering solutions to restore desired smoothness, minimize subsequent settlement, and ensure acceptable long-term performances for highway-railway at-grade crossings. These are site-specific and based on historical performance, the present observed performance and condition, and measurable parameters for the particular crossing. The model decision-making process includes three options, depending on the source(s) of the crossing roughness. The process can involve merely making improvements to the quality of the pavement approaches. Another scenario can be to replace only the deteriorated crossing surface. The most involved solution is the complete renewal of the crossing surface, track panel, and underlying support to rectify a chronic problem that may be inhibiting the crossing from achieving optimum performance.

Mathematical modeling of fluid movement inside the eyeball during intravitreal injection

2021 ◽  
pp. 106-109
Author(s):  
D.V. Lipatov ◽  
◽  
S.A. Skladchikov ◽  
N.P. Savenkova ◽  
V.V. Novoderezkin ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Residence Time ◽  
Complex Structure ◽  
Posterior Vitreous Detachment ◽  
Vitreous Body ◽  
Complete Removal ◽  
Intravitreal Injections ◽  
The World

Background. The avalanche-like growth of intravitreal injections in the world has significantly increased interest in the hemodynamics of the processes that occur in the eye when a drug is injected into the vitreous cavity. Every year, the number of intravitreally used drugs and promising areas in which they can be used is growing. This also applies to the creation of new combined medicines and the development of drugs with a long-term therapeutic effect. Aims. Create mathematical model of eyeball to evaluate the movement of the drug substance in it; to estimate the time of the drug's presence in the eye cavity before its complete removal, to characterize the ways of its removal from the eye cavity; to assess the significance of posterior vitreous detachment during the time when the drug is present in the eye cavity; to evaluate the effect on the hydrodynamics of the depth of drug administration. Results. When the drug is administered closer to the center of the eyeball, its residence time increases in comparison with the parietal administration. With a complete posterior detachment of the vitreous body, the time of finding the drug in the eye is prolonged compared to its absence. The obtained results of mathematical modeling of the movement of the drug administered intravitreally cannot be mechanically transferred to the human eye, due to the more complex structure of the latter. Key words: intravitreal injections, vitreous body, mathematic computing.

scholarly journals Meningiomas of pineal region in children

2007 ◽  
Vol 65 (4a) ◽  
pp. 1000-1006 ◽  
Author(s):  
Hamilton Matushita ◽  
Fernando Campos Pinto ◽  
José Píndaro Pereira Plese
Keyword(s):  
Clinical Presentation ◽  
Complete Removal ◽  
Pineal Region ◽  
Total Resection ◽  
Long Term Follow Up ◽  
One Year ◽  
Velum Interpositum ◽  
Transtentorial Approach

Meningiomas are uncommon tumors in children and either more rarely encountered in the pineal region. We report two cases of meningioma of the pineal region in children. One of these cases was a five years-old girl and the other a one year-old boy. No specific clinical presentation or tomographic examinations findings was identified before treatment, suggestive of a diagnosis of menigioma. The clinical and laboratory features were very similar to the most common tumors of the pineal region. Prior to the surgery, the histology of these tumors was not suspected. Both patients underwent direct surgery and complete removal was achieved by a suboccipital transtentorial approach. The tumors originated from velum interpositum in both cases. At the follow up, one case presented with recurrence six years later, and she underwent a reoperation with total resection without morbidity. Long-term follow up presented no other recurrences.

Immobilization of sulfur by constructing three-dimensional nitrogen rich carbons for long life lithium–sulfur batteries

2017 ◽  
Vol 5 (18) ◽  
pp. 8360-8366 ◽  
Author(s):  
Yingbin Tan ◽  
Zhihui Zheng ◽  
Shiting Huang ◽  
Yongzhe Wang ◽  
Zhonghui Cui ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Cycling Performance ◽  
N Content ◽  
Lithium Sulfur Batteries ◽  
Long Life ◽  
Pyridinic N ◽  
Lithium Sulfur

A 3D nanostructured NCNTs–CS–ZIF-8(C) hybrid with high pyridinic-N content exhibits stable long-term cycling performance.

scholarly journals A Conservative Approach to a Peripheral Ameloblastoma

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Rocco Borrello ◽  
Elia Bettio ◽  
Christian Bacci ◽  
Marialuisa Valente ◽  
Stefano Sivolella ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Soft Tissues ◽  
Complete Removal ◽  
The Other ◽  
Conservative Approach ◽  
Choice Of Treatment ◽  
Long Term Follow Up ◽  
One Year

Peripheral Ameloblastoma (PA) is the rarest variant of ameloblastoma. It differs from the other subtypes of ameloblastoma in its localization: it arises in the soft tissues of the oral cavity coating the tooth bearing bones. Generally, it manifests nonaggressive behavior and it can be treated with complete removal by local conservative excision. In this study we report a case of PA of the maxilla in a 78-year-old female patient and we describe the four different histopathological patterns revealed by histological examination. After local excision and diagnosis, we planned a long term follow-up: in one year no recurrence had been reported. The choice of treatment is illustrated in Discussion.

A borate decorated anion-immobilized solid polymer electrolyte for dendrite-free, long-life Li metal batteries

2019 ◽  
Vol 7 (34) ◽  
pp. 19970-19976 ◽  
Author(s):  
Cheng Ma ◽  
Yiming Feng ◽  
Fangzhou Xing ◽  
Lin Zhou ◽  
Ying Yang ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Polymer Electrolyte ◽  
Solid Polymer Electrolyte ◽  
Transference Number ◽  
High Ionic Conductivity ◽  
Solid Polymer ◽  
Lithium Metal ◽  
Lithium Metal Batteries ◽  
Long Life

A borate decorated anion-immobilized solid polymer electrolyte effectively integrates high ionic conductivity, high Li+ transference number and reasonably mechanical integrity, enabling long-term cycling stability for dendrite-free lithium metal batteries.

scholarly journals Long-Term Projection of Renewable Energy Technology Diffusion

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4261 ◽  
Author(s):  
Tadeusz Skoczkowski ◽  
Sławomir Bielecki ◽  
Joanna Wojtyńska
Keyword(s):  
Renewable Energy ◽  
Technology Diffusion ◽  
Renewable Energy Sources ◽  
Unit Cost ◽  
Learning Curves ◽  
Novel Technologies ◽  
The Future ◽  
Term Energy ◽  
The Eu

The EU aims at increasing the use of renewable energy sources (RES), mainly solar-photovoltaic (PV) and wind technologies. Projecting the future, in this respect, requires a long-term energy modeling which includes a rate of diffusion of novel technologies into the market and the prediction of their costs. The aim of this article has been to project the pace at which RES technologies diffused in the past or may diffuse in the future across the power sector. This analysis of the dynamics of technologies historically as well as in modeling, roadmaps and scenarios consists in a consistent analysis of the main parameters of the dynamics (pace of diffusion and extent of diffusion in particular markets). Some scenarios (REMIND, WITCH, WEO, PRIMES) of the development of the selected power generation technologies in the EU till 2050 are compared. Depending on the data available, the learning curves describing the expected development of PV and wind technologies till 2100 have been modeled. The learning curves have been presented as a unit cost of the power versus cumulative installed capacity (market size). As the production capacity increases, the cost per unit is reduced thanks to learning how to streamline the manufacturing process. Complimentary to these learning curves, logistic S-shape functions have been used to describe technology diffusion. PV and wind generation technologies for the EU have been estimated in time domain till 2100. The doubts whether learning curves are a proper method of representing technological change due to various uncertainties have been discussed. A critical analysis of effects of the commonly applied models for a long-term energy projection (REMIND, WITCH) use has been conducted. It has been observed that for the EU the analyzed models, despite differences in the target saturation levels, predict stagnation in the development of PV and wind technologies from around 2040. Key results of the analysis are new insights into the plausibility of future deployment scenarios in different sectors, informed by the analysis of historical dynamics of technology diffusion, using to the extent possible consistent metrics.

Cement within Cement Revision Hip Arthroplasty a Minimum 5 Year Follow-Up Study

1998 ◽  
Vol 8 (3) ◽  
pp. 129-137 ◽  
Author(s):  
J.P. Holland ◽  
F.A. Weber
Keyword(s):  
Femoral Stem ◽  
Femoral Shaft ◽  
Complete Removal ◽  
Senior Author ◽  
Long Term Results ◽  
Cemented Stem ◽  
Revision Hip Surgery

Complete removal of femoral shaft cement during revision hip surgery is a difficult task prone to complications. If the cement bone interface is intact however, is there a place for its preservation and re-use with a new cemented stem? The results are reported of 51 cement within cement femoral stem revisions carried out between 1984 and 1991 with a minimum of 5 years’ follow-up, and a mean of 7.8 years. Excluding patients lost or deceased, 39 hips in 38 patients were reviewed clinically and radiologically. Eighty-two percent of these were still functioning in situ, 72% were excellent or good using the HSS scoring system and 97% had no radiological evidence of loosening. Femoral stem failure due to aseptic loosening occurred in 4 cases (10%) between 4 and 12 years after revision. Comparing this series to a previous revision hip series by the senior author, there appears to be no deterioration in long term results using this technique, and a better long term radiological outcome.

scholarly journals Short- and Long-Term Effects of Nonconsciously Processed Ambient Scents in a Servicescape: Findings From Two Field Experiments

2019 ◽  
Vol 22 (4) ◽  
pp. 440-455 ◽  
Author(s):  
Anna Girard ◽  
Marcel Lichters ◽  
Marko Sarstedt ◽  
Dipayan Biswas
Keyword(s):  
Large Scale ◽  
Field Experiments ◽  
Field Studies ◽  
Long Term Effects ◽  
Short Term ◽  
Railway Company ◽  
Short And Long Term ◽  
Ambient Scents ◽  
Short Term Effects

Ambient scents are being increasingly used in different service environments. While there is emerging research on the effects of scents, almost nothing is known about the long-term effects of consumers’ repeated exposure to ambient scents in a service environment as prior studies on ambient scents have been lab or field studies examining short-term effects of scent exposure only. Addressing this limitation, we examine the short- and long-term effects of ambient scents. Specifically, we present a conceptual framework for the short- and long-term effects of nonconsciously processed ambient scent in olfactory-rich servicescapes. We empirically test this framework with the help of two large-scale field experiments, conducted in collaboration with a major German railway company, in which consumers were exposed to a pleasant, nonconsciously processed scent. The first experiment demonstrates ambient scent’s positive short-term effects on consumers’ service perceptions. The second experiment—a longitudinal study conducted over a 4-month period—examines scent’s long-term effects on consumers’ reactions and demonstrates that the effects persist even when the scent has been removed from the servicescape.

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