Use of tire derived aggregate in tunnel cut-and-cover

A case-history is reported in which tire derived aggregate (TDA) was successfully applied to reduce the weight of fill upon a cut-and-cover railway tunnel. Subsequent 3D numerical analyses are used to explore the effect of different assumptions about the constitutive model of the TDA material. Alternative dispositions of TDA around the tunnel section are also examined. Reductions of up to 60% in lining bending moment may be achieved. For the case analyzed the elastic description of the TDA has little influence on tunnel lining loads, although is important for fill settlement estimates.Peer ReviewedPostprint (author's final draft

Materiales Supramoleculares basados en Redes Autoensambladas por Interacciones de Enlace de Hidrógeno Cooperativas

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Orgáncia. Fecha de lectura: 13-02-202

The half-sine method: a new accurate location method based on wavelet transform for transmission-line protection from single-ended measurements

In this work, a new and accurate method based on the wavelet transform is proposed for fault location in transmission-line systems. The proposed wavelet method consists of the analysis of the transient signal measured at a single end of the transmission line. Aerial current modes are used, and zero modes are included in the fault-detection scheme for low fault-inception angles. The fault distance is evaluated using the wavelet modulus maxima technique and a method based on the response to a half-sine voltage is proposed to overcome drawbacks arising from the limited sampling frequency and low fault-inception angle. The fault distance is calculated using the difference between the time when a 100 kHz half-sine signal is sent and the time when the derivative signal is received. The proposed algorithm is tested considering harmonic distortion and varying fault resistance, ground resistivity, location and inception angle. The high accuracy of the proposed algorithm is obtained even for faults close to the bus and low inception angle

Characterization of parasitic impedance in PCB using a flexible test probe based on a curve-fitting method

Switching in power semiconductors with emerging materials such as silicon carbide (SiC) leads to undesired overvoltages and oscillations that limit switching frequency, largely due to impedance in the current commutation loop. Minimizing this parasitic impedance in printed circuit boards (PCB) requires precise characterization. To this end, this work presents a new measurement method based on obtaining S-parameters with a vector network analyzer (VNA) and on using a shielded flexible probe with mobile test terminals. The flexible probe uses a metal shielding plane perpendicular to the PCB to prevent the main measurement errors resulting from the variation in the magnetic flux responsible for loop inductance during the VNA frequency sweep. The proposed curve-fitting procedure consists of measuring the characteristic impedance and propagation time of the traces, considering they form ideal transmission lines. These values are used for a nonlinear least squares adjustment for the actual line (with losses). Finally, an experimental assembly with microstrip transmission lines was developed to validate the proposed method experimentally. The experimental results were compared with those obtained by using a rigid test fixture as a reference, those calculated analytically and those obtained from partial element equivalent circuit (PEEC) simulation. The curve-fitting method yields better results than the analytical and the simulation methods and they exhibit (up to 350 MHz) precisions of 1.37% in the characteristic impedance measurement and of 0.81% in the propagation time

Thermodynamic and Kinetic Stabilities of G-Quadruplexes in Apolar Solvents

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Organic Letters, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.orglett.6b03606In contrast to more polar media, G-quadruplex assembly reveals remarkably high thermodynamic and kinetic stability in toluene solutions. Depending on the substituents installed at the lipophilic guanosine, either a dodecamer or an octamer complex is formed in the presence of K+ or Na+ salts that resist conditions of high dilution and elevated temperatures without exhibiting significant dissociation. Moreover, kinetic exchange between complexed and uncomplexed G is slow enough in NMR to monitor G-quadruplex formation along a day time scaleThe EU (ERC-Starting Grant 279548) and MINECO (CTQ2014-57729-P) is gratefully acknowledged. E.F. thanks Sharif University of Technology of Iran for financial support. M.M.-A. acknowledges a FPI grant from MINEC

Traffic Control Magnetic Loops Electric Characteristics Variation Due to the Passage of Vehicles Over Them

"(c) 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."The effect on the buried magnetic loop response when vehicles pass over them is determined. A program is designed and used to obtain the magnetic profile of several vehicles when passing over a rectangular loop. The theoretical values are compared with the actual measurements and the accuracy of the model is checked. Besides, a new oscillator circuit, a component of which is the loop, is presented. Induction change is used to cause the oscillation frequency modification of circuit, which in turn is one of the changes used for vehicles detection, identification and classification.This work was supported in part by the City Council of Valencia in Spain and in part by Company ETRA I+D S.A.Mocholí Salcedo, A.; Arroyo Núñez, JH.; Milián Sánchez, VM.; Verdú Martín, GJ.; Arroyo Nuñez, A. (2017). Traffic Control Magnetic Loops Electric Characteristics Variation Due to the Passage of Vehicles Over Them. IEEE Transactions on Intelligent Transportation Systems. 18(6):1540-1548. doi:10.1109/TITS.2016.2612579S1540154818

A survey of islanding detection methods for microgrids and assessment of non-detection zones in comparison with grid codes

Detection of unintentional islanding is critical in microgrids in order to guarantee personal safety and avoid equipment damage. Most islanding detection techniques are based on monitoring and detecting abnormalities in magnitudes such as frequency, voltage, current and power. However, in normal operation, the utility grid has fluctuations in voltage and frequency, and grid codes establish that local generators must remain connected if deviations from the nominal values do not exceed the defined thresholds and ramps. This means that islanding detection methods could not detect islanding if there are fluctuations that do not exceed the grid code requirements, known as the non-detection zone (NDZ). A survey on the benefits of islanding detection techniques is provided, showing the advantages and disadvantages of each one. NDZs size of the most common passive islanding detection methods are calculated and obtained by simulation and compared with the limits obtained by ENTSO-E and islanding standards in the function of grid codes requirements in order to compare the effectiveness of different techniques and the suitability of each one

Treatment of Lower Pole Renal Stones. Extracorporeal Shockwave Lithotripsy Versus Intrarenal and Percutaneous Surgery

Introducción: la litotricia extracorpórea por ondas de choque (LEOC) es el tratamiento usado en el 80-90% de los casos de litiasis renal. Las técnicas endourológicas como la cirugía intrarrenal retrógrada (CIR), la nefrolitotomía percutánea (NLP) y sus miniaturizaciones (miniperc) están ganando importancia gracias a su alta eficacia. Cuando se trata del cáliz inferior la litotricia extracorpórea es la que presenta peores resultados, pero es difícil determinar las indicaciones para tratar con una técnica concreta. El objetivo de esta revisión es determinar la eficacia y seguridad de estas técnicas en el manejo de la litiasis renal en cáliz inferior. Material y métodos: revisión de 12 estudios que evalúan resultados de una, dos o las tres técnicas en términos de eficacia, tiempo de intervención, estancia hospitalaria, complicaciones, maniobras auxiliares y re-tratamiento. Resultados: la LEOC presenta peores resultados cuando el cálculo es de mediano tamaño, menor tiempo de intervención y estancia, más complicaciones y altas tasas de re-tratamiento. La eficacia de la CIR y la NLP no se ve tan afectada por el tamaño de la litiasis, presentando buenos resultados y menores tasas de litiasis residuales, pero mayor tiempo de intervención y de estancia hospitalaria. Conclusiones: la litotricia extracorpórea presenta resultados inferiores, pero bastante aceptables considerando su baja invasividad y corta estancia hospitalaria, características que la hacen preferible en pacientes seleccionados. Las técnicas endourológicas demuestran una gran eficacia a expensas de ser más invasivas y costosas, aunque a veces sean preferibles para evitar la necesidad de re-tratamiento.Introduction: extracorporeal shockwave lithotripsy (SWL) is used in the 80-90% of the cases of renal lithiasis. Endourological techniques such as retrograde intrarenal surgery (RIRS) or percutaneous nephrolithotomy (PCNL) and its miniaturizations (miniperc) are gaining importance because they are highly effective treatments. Regarding the treatment of the nephrolithiasis of the lower pole, the extracorporeal lithotripsy presents worse results, but it still difficult to set up the indications to treat with a certain technique. The purpose of this review is to stablish the effectivity and safety profile of these techniques in the management of the lower renal pole lithiasis. Materials and Methods: we conducted a review of 12 studies that evaluate results of one, two or three of the techniques in terms of effectivity, operative time, hospital stay, complications, auxiliary procedures and re-treatment. Results: SWL presents lower stone-free rates when the lithiasis is medium or big sized, shorter operative time and hospital stay, more complications and high rates of re-treatment. The effectivity of RIRS and PCNL does not change a lot with larger lithiasis, presenting good results and lower residual lithiasis rates. The longer operative time was performed with RIRS and the longer hospital stay with PCNL. The complications rate varies, being more important with PCNL. Re-treatment rates are low with RIRS and PCNL. Conclusions: these three techniques show good results in the management of lower pole lithiasis, although SWL presents worse results in comparison, but considering its reduced invasiveness and short hospital stay, it is the chosen technique for many patients. Endourological techniques show better results at expense of their invasiveness and higher cost, although sometimes they are preferable in order to prevent re-treatment

Association between Physiological and Subjective Aspects of Pain and Disability in Post-Stroke Patients with Shoulder Pain: A Cross-Sectional Study

Background: Patients often experience pain as a result of a stroke. However, the mechanism of this pain remains uncertain. Our aim was to investigate the relationship between pressure pain thresholds (PPTs) and disability pain in patients with hemiplegic shoulder pain (HSP). Methods: Twenty-six post-stroke patients (age 53.35 +/- 13.09 years) and healthy controls (54.35 +/- 12.37 years) participated. We investigated spontaneous shoulder pain, disability pain perception through the shoulder pain and disability index (SPADI), and the PPTs over joint C5–C6, upper trapezius, deltoid, epicondyle, second metacarpal, and tibialis anterior, bilaterally. Results: The analysis of variance (ANOVA) showed significant differences in pain between groups (p < 0.001) and differences in the SPADI (p < 0.001) between groups but not between sides for PPTs over deltoid (group: p = 0.007; side: p = 0.750), epicondyle (group: p = 0.001; side: p = 0.848), and tibialis anterior (group: p < 0.001; side: p = 0.932). Pain in the affected arm was negatively associated with PPTs over the affected epicondyle (p = 0.003) and affected tibialis anterior (p = 0.009). Pain (SPADI) appeared negatively correlated with PPTs over the affected epicondyle (p = 0.047), and disability (SPADI) was negatively associated with PPTs over the affected tibialis anterior (p = 0.041). Conclusions: Post-stroke patients showed a relationship between widespread pressure pain hypersensitivity with lower PPT levels and pain disability perception, suggesting a central sensitization mediated by bilateral and symmetric pain patterns