969 resultados para Corner Reflector


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The term autophagic cell death (ACD) initially referred to cell death with greatly enhanced autophagy, but is increasingly used to imply a death-mediating role of autophagy, as shown by a protective effect of autophagy inhibition. In addition, many authors require that autophagic cell death must not involve apoptosis or necrosis. Adopting these new and restrictive criteria, and emphasizing their own failure to protect human osteosarcoma cells by autophagy inhibition, the authors of a recent Editor's Corner article in this journal argued for the extreme rarity or nonexistence of autophagic cell death. We here maintain that, even with the more stringent recent criteria, autophagic cell death exists in several situations, some of which were ignored by the Editor's Corner authors. We reject their additional criterion that the autophagy in ACD must be the agent of ultimate cell dismantlement. And we argue that rapidly dividing mammalian cells such as cancer cells are not the most likely situation for finding pure ACD.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Nationally, there are questions regarding the design, fabrication, and erection of horizontally curved steel girder bridges due to unpredicted girder displacements, fit-up, and locked-in stresses. One reason for the concerns is that up to one-quarter of steel girder bridges are being designed with horizontal curvature. There is also an urgent need to reduce bridge maintenance costs by eliminating or reducing deck joints, which can be achieved by expanding the use of integral abutments to include curved girder bridges. However, the behavior of horizontally curved bridges with integral abutments during thermal loading is not well known nor understood. The purpose of this study was to investigate the behavior of horizontal curved bridges with integral abutment (IAB) and semi-integral abutment bridges (SIAB) with a specific interest in the response to changing temperatures. The long-term objective of this effort is to establish guidelines for the use of integral abutments with curved girder bridges. The primary objective of this work was to monitor and evaluate the behavior of six in-service, horizontally curved, steel-girder bridges with integral and semi-integral abutments. In addition, the influence of bridge curvature, skew and pier bearing (expansion and fixed) were also part of the study. Two monitoring systems were designed and applied to a set of four horizontally curved bridges and two straight bridges at the northeast corner of Des Moines, Iowa—one system for measuring strains and movement under long term thermal changes and one system for measuring the behavior under short term, controlled live loading. A finite element model was developed and validated against the measured strains. The model was then used to investigate the sensitivity of design calculations to curvature, skew and pier joint conditions. The general conclusions were as follows: (1) There were no measurable differences in the behavior of the horizontally curved bridges and straight bridges studied in this work under thermal effects. For preliminary member sizing of curved bridges, thermal stresses and movements in a straight bridge of the same length are a reasonable first approximation. (2) Thermal strains in integral abutment and semi-integral abutment bridges were not noticeably different. The choice between IAB and SIAB should be based on life – cycle costs (e.g., construction and maintenance). (3) An expansion bearing pier reduces the thermal stresses in the girders of the straight bridge but does not appear to reduce the stresses in the girders of the curved bridge. (4) An analysis of the bridges predicted a substantial total stress (sum of the vertical bending stress, the lateral bending stress, and the axial stress) up to 3 ksi due to temperature effects. (5) For the one curved integral abutment bridge studied at length, the stresses in the girders significantly vary with changes in skew and curvature. With a 10⁰ skew and 0.06 radians arc span length to radius ratio, the curved and skew integral abutment bridges can be designed as a straight bridge if an error in estimation of the stresses of 10% is acceptable.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The AASHO specifications for highway bridges require that in designing a bridge, the live load must be multiplied by an impact factor for which a formula is given, dependent only upon the length of the bridge. This formula is a result of August Wohler's tests on fatigue in metals, in which he determined that metals which are subjected to large alternating loads will ultimately fail at lower stresses than those which are subjected only to continuous static loads. It is felt by some investigators that this present impact factor is not realistic, and it is suggested that a consideration of the increased stress due to vibrations caused by vehicles traversing the span would result in a more realistic impact factor than now exists. Since the current highway program requires a large number of bridges to be built, the need for data on dynamic behavior of bridges is apparent. Much excellent material has already been gathered on the subject, but many questions remain unanswered. This work is designed to investigate further a specific corner of that subject, and it is hoped that some useful light may be shed on the subject. Specifically this study hopes to correlate, by experiment on a small scale test bridge, the upper limits of impact utilizing a stationary, oscillating load to represent axle loads moving past a given point. The experiments were performed on a small scale bridge which is located in the basement of the Iowa Engineering Experiment Station. The bridge is a 25 foot simply supported span, 10 feet wide, supported by four beams with a composite concrete slab. It is assumed that the magnitude of the predominant forcing function is the same as the magnitude of the dynamic force produced by a smoothly rolling load, which has a frequency determined by the passage of axles. The frequency of passage of axles is defined as the speed of the vehicle divided by the axle spacing. Factors affecting the response of the bridge to this forcing function are the bridge stiffness and mass, which determine the natural frequency, and the effects of solid damping due to internal structural energy dissipation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This research, initiated in October 1992, was located at the intersection of Blairs Ferry Road and Lindale Drive in the City of Marion. The wall is located on the southeast corner of the intersection. Reinforced retaining wall construction started with a five inch base of roadstone with one inch of sand for leveling purposes. One and one-half to two feet of one inch clean stone was placed behind the blocks. A four inch perforated plastic pipe was placed approximately nine inches from the bottom of the one inch clean stone. The Tenswal, tensar geogrid was placed at every third layer. Openings in the Tenswal are hooked over plastic dowels in the blocks. The tenswal reaches from the face of the wall back 5' to 8'. The cost for constructing this wall was $124,400. The wall has performed well for the past five years. The wall improves the aesthetics of a high traffic volume intersection of an urban area. Many positive comments have been received by the city regarding its appearance. The City of Marion has been pleased with the wall and has used this type of wall on subsequent projects.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Summary: Feeling mirror - reflector of feeling states during meaningful learning experiences

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El propòsit d’aquest estudi és analitzar quin és l’índex d’efectivitat en diferents situacions a pilota aturada (penals, faltes sense barrera i córners) en el futbol platja dins el context d’equips amateurs que participen en els tornejos de Blanes i Tossa de Mar. A l’hora de realitzar-lo he tingut en compte una sèrie de variables, com ara la precisió del colpeig, el tipus de colpeig, la superfície de contacte o la situació inicial de la pilota, és a dir, des d’on provenia la trajectòria inicial d’ aquesta, tot comprovant també com canvien els resultats en funció de la zona i del costat que es realitza el remat. Respecte els resultats, aquests demostren que l’índex d’efectivitat en aquest tipus d’accions és més baix en relació amb altres esports semblants com el futbol i el futbol sala.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

L’objectiu del present estudi va consistir en estudiar el percentatge de gols a pilota aturada de la Lliga BBVA i la Premier League, establint el percentatge d’efectivitat de cadascuna d’elles. A més, es volia analitzar la freqüència de les diferents tipus d’accions a pilota aturada i substituir el terme estratègia per accions a pilota aturada. Amb aquest objectiu es van analitzar 80 partits disputats per equips de futbol professional en la temporada 2012-13 de la Lliga BBVA i la Premier League mitjançant l’anàlisi de vídeos. Les variable dependent era la consecució o no del gol, tenint com a variables independents 4 tipus d’accions a pilota aturada: tirs lliures directes, tirs lliures indirectes, córners i penals. Els resultats indiquen un major número de gols provinents d’accions a pilota aturada en la Lliga BBVA que en la Premier League, 29,8% per un 23,4% respectivament. Tot i això, s’ha comprovat com els percentatges d’efectivitat són pràcticament idèntics: 4,54% a la Lliga BBVA i 4,58% a la Premier League. Finalment, s’ha identificat el córner com l’acció que més es produeix en el joc, seguit de les faltes directes, els penals i les faltes indirectes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

L’aprenentatge de la lectoescriptura és complex. Aprendre a llegir i escriure implica dominar moltes habilitats. A l’escola habitualment es treballa de forma mecànica i poc significativa. L’objectiu d’aquest projecte és conèixer si les lletres de confegir de Maria Montessori encara tenen vigència en l’actualitat. En aquest sentit, s’ha valorat el racó on hi ha aquest material, ja existent a l’escola, per posteriorment fer una proposta de millora i desenvolupar-la dins el marc d’una aula de P5. A través d’algunes situacions reals d’aula volem il·lustrar les possibilitats de la nostra proposta. L’experiència realitzada amb infants de l’últim curs d’Educació Infantil indica que treballar el procés de lectoescriptura amb aquest material és una bona eina per atendre a la diversitat existent a les aules actuals.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The routine maintenance along Iowa's highways and roadways during the summer growing season is a time consuming and costly endeavor. Trimming around guardrail posts and delineator posts is especially costly due to the handwork required. Trimming costs account for approximately 50% of the shoulder mowing costs according to expense figures obtained from the Iowa Department of Transportation (DOT), Office of Maintenance. The FY 2001 statewide trimming costs for the Iowa DOT was approximately $430,000 ($305,000 labor, $125,000 equipment and materials). This product would be required to perform well for 9-21 years, on average, in order to recoup the cost of installation. This includes the durability of the product, but not the cost of repair due to traffic damage, snowplow and wing damage, or damage caused by mowing operations. Maintenance costs associated with vegetation creep over the mats and repair costs would extend the required service life. As a result of resource realignment, the Iowa DOT roadside maintenance policy, for FY 2003 and the future, will be to eliminate trimming around delineator posts unless the reflector is obstructed. This policy change will effectively eliminate the need for weed control mats due to the significant reduction in trimming. The use of the weed control mats could be justified in areas that are dangerous to maintenance workers such as guardrail installations in high traffic areas. Because the delineator posts are further from the edge of the traveled roadway, there is a reduced risk to the maintenance workforce while hand trimming. Because the DuroTrim Vegetation Control Mats appear to have performed adequately in the field trial, they could be considered for use, where safety conditions warrant. That use should be limited, however, due to the considerable initial cost and changes in Iowa DOT roadside maintenance policy. Application should be limited to instances where the use of the DuroTrim Vegetation Control Mats would have a significant impact on the safety of the roadside maintenance workers. The cost savings, due to the elimination of the trimming and mowing alone, is not enough to justify their use in most situations at their current cost. The test sections will continue to be monitored periodically so that approximate service life can be determined.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This year we present three papers on recent advances in paediatrics from the fields of neonatology, adolescent medicine and Duchenne muscular dystrophy. 1. Recent studies question the application of pure oxygen for neonatal reanimation and suggest that lower concentrations or even air may be more adequate for the reanimation of most newborns. 2. Bullying is an aggressive, repetitive and intentionally blessing behaviour. It is observed mainly at school and the victims are usually children with a weak personality or children suffering from chronic diseases. The doctor's role is to detect this behaviour and to help protect the victims. 3. The respiratory surveillance of patients with Duchenne muscular dystrophy is the corner-stone of their management. An algorithm allows to time correctly the initiation of non-invasive ventilation and to insure as long as possible a good life quality.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Storm Lake, the state's fourth largest natural lake, has been the centerpiece of significant economic development, including a resort, water park, and state marina. While there have been considerable improvements to the lake's water quality through a major on-going lake restoration program and watershed project, the Little Storm Lake area still needs to be addressed. Little Storm Lake is a 190 acre area on the nmihwest side of Storm Lake. The water level in both areas is based on the dam height located on the southeast corner of Storm Lake. Approximately 70% of the water from the watershed flows through Little Storm Lake. Little Storm Lake originally had the ability to remove much of the sediment and nutrients from incoming waters. However, due to degradation, proper wetland function has been compromised. Under normal hydrologic conditions Little Storm Lake has the potential to function as a sediment trap for Storm Lake, but tllis capacity is overwhelmed during high flows. Little Storm Lake is at or near its sediment trapping capacity, which results in higher sediment transport into Storm Lake. Resuspension of sediments due to wind and other in-lake dynamics, such as rough fish, further exacerbate the total turbidity from suspended sediment and results in movement of sediment from Little Storm Lake into Storm Lake. This project includes a fish barrier and water retention structure between Little Storm Lake and Storm Lake and the construction of a pumping station and associated equipment. The project involves periodic dewatering of Little Storm Lake during years of favorable climatological conditions to consolidate the sediments and revegetate the area. Construction of the fish banier would aid restoration efforts by preventing rough fish from destroying the vegetation and would decrease recruitment of rough fish by limiting their spawning area. In the future, if the diminished trapping capacity of Little Storm Lake still results in sediment moving into Storm Lake, a dredging project would be initiated to deepen Little Storm Lake.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Price Creek is a 13 mile long stream located in SE Benton County and the NE corner of Iowa County. It ends below the village of Amana where it flows into the Iowa River. The Iowa and Benton County Soil & Water Conservation Districts (SWCDs) applied (and were tentatively approved) for 319/WPF/WSPF funding to treat livestock and water quality issues in this watershed over the next three years. That project’s funds were allocated for a Project Coordinator, information and education activities, and cost share for Best Management Practices (BMPs) directed toward livestock issues and nutrient issues. Soil erosion and sedimentation are also problems in this 18,838 acre watershed. It is 64% HEL (highly erodible land) and 58% of it is cropped. With a coordinator working with Price Creek producers, this would be an excellent time to also address the soil loss and sedimentation issues in this watershed. We will offer additional cost share incentives on BMPs targeting soil erosion on the critical areas we’ve identified. We are applying to IWIRB for additional funding to allow us to cost share specific BMPs up to 75% to treat soil loss in these critical areas of the Price Creek Watershed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Portland cement concrete (PCC) pavement undergoes repeated environmental load-related deflection resulting from temperature and moisture variations across pavement depth. This has been recognized as resulting in PCC pavement curling and warping since the mid-1920s. Slab curvature can be further magnified under repeated traffic loads and may ultimately lead to fatigue failures, including top-down and bottom-up transverse, longitudinal, and corner cracking. It is therefore significant to measure the “true” degree of curling and warping in PCC pavements, not only for quality control (QC) and quality assurance (QA) purposes, but also for better understanding of its relationship to long-term pavement performance. Although several approaches and devices—including linear variable differential transducers (LVDTs), digital indicators, and some profilers—have been proposed for measuring curling and warping, their application in the field is subject to cost, inconvenience, and complexity of operation. This research therefore explores developing an economical and simple device for measuring curling and warping in concrete pavements with accuracy comparable to or better than existing methodologies. Technical requirements were identified to establish assessment criteria for development, and field tests were conducted to modify the device to further enhancement. The finalized device is about 12 inches in height and 18 pounds in weight, and its manufacturing cost is just $320. Detailed development procedures and evaluation results for the new curling and warping measuring device are presented and discussed, with a focus on achieving reliable curling and warping measurements in a cost effective manner.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In soccer, dead-ball moves are those in which the ball is returned to play from a stationary position following an interruption of play. The aim of this study was to analyse the effectiveness of one such dead-ball move, namely corner kicks, and to identify the key variables that determine the success of a shot or header following a corner, thereby enabling a model of successful corner kicks to be proposed. We recorded 554 corner kicks performed during the 2010 World Cup in South Africa and carried out a univariate, bivariate and multivariate analysis of the data. The results indicated that corners were of limited effectiveness in terms of the success of subsequent shots or headers. The analysis also revealed a series of variables that were significantly related to one another, and this enabled us to propose an explanatory model. Although this model had limited explanatory power, it nonetheless helps to understand the execution of corner kicks in practical terms.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The objective of this master's thesis is to evaluate the optimum performance of sixsectored hexagonal layout of WCDMA (UMTS) network and analyze the performance at the optimum point. The maximum coverage and the maximum capacity are the main concern of service providers and it is always a challenging task for them to achieve economically. Because the optimum configuration of a network corresponds to a configuration which minimizes the number of sites required to provide a target service probability in the planning area which in turn reduces the deployment cost. The optimum performance means the maximum cell area and themaximum cell capacity the network can provide at the maximum antenna height satisfying the target service probability. Hexagon layout has been proven as the best layout for the cell deployment. In this thesis work, two different configurations using six-sectored sites have been considered for the performance comparison. In first configuration, each antenna is directed towards each corner of hexagon, whereas in second configurationeach antenna is directed towards each side of hexagon. The net difference in the configurations is the 30 degree rotation of antenna direction. The only indoor users in a flat and smooth semi-urban environment area have been considered for the simulation purpose where the traffic distribution is 100 Erl/km2 with 12.2 kbps speech service having maximum mobile speed of 3 km/hr. The simulation results indicate that a similar performance can be achieved in both the configurations, that is, a maximum of 947 m cellrange at antenna height of 49.5 m can be achieved when the antennas are directed towards the corner of hexagon, whereas 943.3 m cell range atantenna height of 54 m can be achieved when the antennas are directed towards the side of hexagon. However, from the interference point of view the first configuration provides better results. The simulation results also show that the network is coverage limited in both the uplink and downlink direction at the optimum point.