985 research outputs found
On the optimal arrangement of lines in
We show the optimal coherence of lines in is given by
the Welch bound whenever a skew Hadamard of order exists. Our proof uses
a variant of Hadamard doubling that converts any equiangular tight frame of
size into another one of size . Among , this produces equiangular tight frames of new sizes when ,
, , , , , , , , , , , ,
, , , , and
Edge Drain Performance
Edge drain systems are used on new highway construction projects and rehabilitation projects to reduce the moisture content of the pavement block and subgrade. Maintaining dry conditions in and around these components increases the subgrade strength and extends a pavement’s surface life. Edge drain systems can only operate effectively, however, if the entire subsurface drainage system functions properly. While many studies have demonstrated the benefits of edge drain systems, no comprehensive investigation of their performance has been undertaken in the state of Kentucky in over 20 years. After the Kentucky Transportation Cabinet (KYTC) identified problems with an edge drainage system along a segment of Interstate 275 in Kenton County, the agency commissioned researchers at the Kentucky Transportation Center (KTC) to evaluate the performance of edge drains on roadway segments that will be resurfaced in the coming years. Researchers comprehensively inspected 10 roadway segments, assessing several components of their edge drain systems. For edge drain systems with headwalls, researchers found that all headwalls (n =126) were in good condition and free of structural issues. Roughly 29% of the outfall waterways prevented the flow of water from the headwall, while 65% of the outlet waterways were blocked to some extent by gravel, mud, silt, or other debris, and 61% of the outlet pipes were obstructed. Of the edge drain systems draining to catch basin inserts or ditch bottom inlets (n = 110), outfall waterways were clear on 97% of the systems, but just 14% of the edge drains were unobstructed. Based on inspections, edge drain systems were classified as good, compromised, or undetermined (the final designation being used if conditions prevented a full inspection) and identified a probable failure mode. Approximate 75% of the problems found during inspections were related to maintenance, with the remainder the product of construction activities. To preserve edge drains in a functional condition, post-installation inspections should be conducted, and yearly inspections and cleanings of headwalls and outlet pipes completed. Other methods for outletting water (e.g., dry wells) can also be explored
Forensic Pavement Evaluation for US 31 W, Jefferson County, Kentucky Using Ground Penetrating Radar
The Kentucky Transportation Center (KTC) utilized ground penetrating radar technology to provide a forensic evaluation of the existing pavement structure for the US31W pavement rehabilitation Project in Jefferson County, KY. Processed ground penetrating radar data indicated that the integrity of the underlying concrete pavement beneath the asphalt pavement appears to be competent and structurally sound. The clay soil beneath the concrete pavement appears relatively dry and well compacted. The analyzed GPR data also indicated that the average asphalt layer varied by lane throughout the project from 4.89 to 7.59 inches +/- ½ inch and that the underlying concrete layer average varied by lane throughout the project from 6.59 to 8.12 inches +/- ½ inch. This information was shared with design engineers in efforts to select the most appropriate pavement rehabilitation repair
Determination of Constructed Pavement Layer Thicknesses Using Nondestructive Testing (NDT)
Using nondestructive testing (NDT) to measure the thickness of pavement layers can improve the overall life of a new concrete and/or asphalt pavement. Conventional test methods require the extraction of a core from the pavement section to verify its thickness. Currently, two NDT technologies are commercially available which eliminate or reduce the need to core the existing pavement for thickness verification. The MIT-Scan-T2 (T2) utilizes magnetic pulse induction coupled with preset metal plates to obtain a thickness value. Measurements can be obtained quickly to an accuracy of +/– 2 mm. Ground Penetrating Radar (GPR) uses electromagnetic radiation to determine pavement layer thickness. However, GPR data need to be calibrated with an actual core during the post-processing phase to obtain the highest accuracy. Additionally, the dielectric properties of pavement sections being assessed with GPR must first stabilize to accurately measure thickness. Generally, stabilization occurs approximately 28 days after the initial placement of the pavement
AID Project Summary Report for Intelligent Compaction
This study reviews data from five roadway construction projects on which intelligent compaction (IC) techniques were used to achieve the more uniform compaction of road-building materials. Kentucky Transportation Center (KTC) researchers looked at IC data collected from these projects — resulting in the production of eight analyzable data sets — to determine whether they complied with the special construction note included in contract documents. The report also compares the intelligent compaction measurement value (ICMV) collected on each project to traditional laboratory results. Researchers used Veta software to analyze geospatial data collected from IC machines during construction work. Of the data sets, three indicated the required minimum coverage pass count had been achieved, although these did not attain the required minimum coverage for ICMV. Three other data sets achieved minimum ICMV coverage, while the final two data sets did not reach minimum coverage for either metric. Regression analysis found no meaningful relationship between density and ICMV. Attention is also paid to challenges which arose during the review of IC data and feedback received from contractors about the use of IC. Contractors appreciate that IC is able to transmit real-time data to operators and provides access to the mat temperature, however they observed inconsistencies with the ICMV for mill/fill projects and on new construction. These inconsistencies are the product of several factors, including cuts, fills, soil types, and the amount of water in the roller. A special construction note with instructions for using IC on Federal-aid projects is included as well. It specifies materials and equipment requirements, contractor responsibilities, construction methods, payment, and performance measures
Bandpass switching in a nonlinear optical loop mirror
A novel device configuration is used to demonstrate wavelength-confined, a bandpass, switching in a nonlinear-optical loop mirror (WOLM). Demonstrated is a self-switching in the soliton regime using a partially reflecting Bragg grating as a wavelength-dependent loss element. Two wavelength operation in which a signal is switched through the use of cross phase modulation, are demonstrated. Observed is the operation of the device confined to wavelengths defined by the grating reflection band
Survey Kriteria Standar Usaha 7 Lokasi Wisata di Kabupaten Manggarai Barat Tahun 2019
As one of the leading destinations, Labuan Bajo offers several natural tourist attractions that are no less interesting. However, some destinations do not yet have a tourism ecosystem management that can balance ethics, aesthetics, economy, and locality to create excellence in quality tourist destinations. The University of Flores' research team has conducted a survey of standard facilities or standard criteria in 7 tourist sites in the West Manggarai district. The seven locations include Tado Village, Melo Traditional Village, Padar Island, Komodo Island, Rangko Cave, Batu Cermin Cave, Senanggoang Lake. The survey conducted aims to capture tourist destinations from three aspects, namely product, service, and management. Based on the results of the survey that has been conducted, it can be said that: several standard facilities in 7 tourist destinations have not been met. Suggestions are given to the Regency Government and managers of tourist destinations in West Manggarai Regency to work together to procure existing facilities and facilities so that tourism objects in the 7 locations become more organized and advanced
Sloped and Mitered Concrete Headwalls
The Kentucky Transportation Cabinet (KYTC) currently uses several pipe culvert end treatments, including standard headwalls, slope and flared headwalls, sloped and parallel headwalls, and safety metal ends. These treatments, however, can pose a safety hazard to motorists and those performing landscaping work (e.g., mowing). Crash statistics from 2012 through 2016 for Kentucky reveal that 49 fatalities and 148 incapacitating injuries occurred in incidents where culverts/headwalls were coded as the first harmful event on the police report. One solution to the safety hazards associated with standard pipe culvert headwalls is to use sloped and mitered concrete headwalls instead. To evaluate the viability of sloped and mitered concrete headwalls for widespread use, Kentucky Transportation Center (KTC) researchers reviewed industry guidance and best practices; observed, documented, and analyzed several projects on which sloped and mitered concrete headwalls were used; developed cost comparisons for sloped and mitered concrete headwalls and conventional headwalls, and evaluated specifications for sloped and mitered concrete headwalls adopted by other states. Sloped and mitered concrete headwalls conform with industry guidance and protect against significant vehicle damage. Observations of sloped and mitered concrete headwalls used on KYTC projects attested to the importance of establishing and applying unambiguous design and construction criteria. Specifically, the grade should be set before a slope and mitered headwall is installed. Furthermore, adding grate bars will improve performance as will securing pipe ends to the headwall. A sample of headwalls should be chosen for long-term monitoring purposes, with inspections conducted each year. Overall, sloped and mitered concrete headwalls are an attractive option given they can be installed quickly and without special equipment, their robust performance, and low cost compared to standard pipe culvert headwalls
- …