Influencia del árido y materiales cementantes suplementarios en las propiedades de los morteros de cal hidratada

Hydrated lime is a historic material currently used in conservation. It hardens slowly by carbonation slowing construction however, supplementary cementitious materials accelerate hardening enhancing strength. Hydrated-lime mortars with rice husk ash–RHA-; ground granulated blastfurnace slag–GGBS- and increasing amounts of two aggregates were studied. Increasing aggregate lowered strength as interfacial zones proliferate; it lowered hygric properties and raised water demand. Aggregate content/composition didn’t affect the high water retention. For the higher aggregate contents (90 days), limestone mortars are c.20% stronger than silica mortars while the (1:1) silica sand mortars are 56% stronger in flexion. Additions increased strength with little impact on hygric properties. GGBS increased strength c.six times. RHA increased strength with little impact on hygric properties due to its great specific surface and high water-demand increasing porosity. GGBS and RHA properties ruling hydrate production and the kinetics of the pozzolanic reaction are considered partially responsible for the mortar property variation.La cal hydratada es un material histórico que se usa en conservación. Endurece despacio por carbonatacion pero materiales cementantes suplementarios aceleran su endurecimiento. Se estudian morteros de cal con escoria granulada molida de alto horno (GGBS) y ceniza de cascara de arroz (RHA) con cantidades variables de dos tipos de árido. GGBS multiplicó por 6 la resistencia mecánica del mortero de cal. RHA afectó ligeramente las propiedades hídricas por su elevada superficie específica que incrementa el agua de mezclado aumentando la porosidad. El aumento de árido redujo la resistencia mecánica, trabajabilidad y propiedades hídricas del mortero. La cantidad/composición del árido no afectó la alta retención de agua. Los morteros de árido de caliza (2:1 y 3:1) incrementaron un 20% su resistencia a la compresión con respecto a los de arena de sílice mientras que la resistencia a la flexión de los arena de sílice (1:1) es 56% superior que sus equivalentes de caliza

Minimal-memory realization of pearl-necklace encoders of general quantum convolutional codes

Quantum convolutional codes, like their classical counterparts, promise to offer higher error correction performance than block codes of equivalent encoding complexity, and are expected to find important applications in reliable quantum communication where a continuous stream of qubits is transmitted. Grassl and Roetteler devised an algorithm to encode a quantum convolutional code with a "pearl-necklace encoder." Despite their theoretical significance as a neat way of representing quantum convolutional codes, they are not well-suited to practical realization. In fact, there is no straightforward way to implement any given pearl-necklace structure. This paper closes the gap between theoretical representation and practical implementation. In our previous work, we presented an efficient algorithm for finding a minimal-memory realization of a pearl-necklace encoder for Calderbank-Shor-Steane (CSS) convolutional codes. This work extends our previous work and presents an algorithm for turning a pearl-necklace encoder for a general (non-CSS) quantum convolutional code into a realizable quantum convolutional encoder. We show that a minimal-memory realization depends on the commutativity relations between the gate strings in the pearl-necklace encoder. We find a realization by means of a weighted graph which details the non-commutative paths through the pearl-necklace. The weight of the longest path in this graph is equal to the minimal amount of memory needed to implement the encoder. The algorithm has a polynomial-time complexity in the number of gate strings in the pearl-necklace encoder.Comment: 16 pages, 5 figures; extends paper arXiv:1004.5179v

Preparation and spectroscopic studies of Hydroxyapatite embedded in Poly(N-Vinylpyrrolidone) matrix

Pure HAp powder was prepared by precipitation and HAp/PVP composites were prepared by casting technique. X-ray diffraction was performed to examine the crystallinity and the complexation between HAp and PVP when the amount of HAp increased. XRD and EDX analysis showed that the concentration 15 wt% is the most confirmation for the formation of HAp. SEM shows more than one form of HAp such as plates, needles and bundles in the morphological structure of pure HAp and 15 wt% of HAp. Two main weight loss regions and two peaks were observed in TGA and DSC thermograms that reveal reduction in the thermal stability of the prepared samples as HAp content increases. The activation energy of the films was decreased with increasing the concentration of HAp. DSC thermographs of the samples show that the values of the glass transition temperatures are decreased with increasing the content of HAp filler which suggest that HAp filler act as plasticizer. The conductivity–temperature plots show linear variation, which suggests an Arrhenius behavior. The conductivity increases with adding HAp content for low concentrations while decreased for the critical concentration (15 wt %) which confirms the XRD results

The Characteristic of Light Vehicles Emissions at Urban Roads in Makassar City

This study aims to analyze the characteristics of HC, NOx, SO2, CO, and CO2 emissions, originating from motor vehicle against vehicle travel time and average speed of vehicles on the main road networks, with heterogeneous traffic situation in the city of Makassar. Location studies conducted on eleven (11) roads, starting from 06:00 am until 20:00 pm. The survey data consists of the vehicle operational characteristics, including engine type, engine size and vehicle life-cycle, where derived from the secondary data. The primary data consists of travel time, vehicle emissions and vehicle speed. The emissions measurements performed with the emissions test equipment (portable measurement system), that is attached to the tool exhaust vehicle condition, moving on a highway with traffic flow heterogeneous situation. The results of the compilation data on vehicle operating characteristics obtained, 51 light vehicle categories with a percentage of 88.14% MPFI and Carburator engine types of 11.86%. The result shows that the amount of CO and CO2 emissions fluctuated over travel time and vehicle speed, while emissions of HC, NOx, and SO2 tends to be constant. The Lowest emissions of CO2 and CO on vehicle speeds ranging between 25-65 km/h and 35-65 km/h. The study results provide be a reference to the next research that is emission factor analysis for 51 light vehicle categories in operation in Makassar City

Superconducting Quantum Point contacts and Maxwell Potential

The quantization of the current in a superconducting quantum point contact is reviewed and the critical current is discussed at different temperatures depending on the carrier concentration as well by suggesting a constant potential in the semiconductor and then a Maxwell potential. When the Fermi wave length is comparable with the constriction width we showed that the critical current has a step-like variation as a function of the constriction width and the carrier concentration.Comment: 13 pages, 8 figures, some figures are clarified; scheduled to appear in an issue in MPLB Vo.21, (2007

Environmental sampling to assess the bioburden of Mycobacterium avium subspecies paratuberculosis in drylot pens on California dairies.

Mycobacterium avium subspecies paratuberculosis (MAP) is a bacterium that can cause substantial economic losses in infected dairy herds due to reduced milk production and increased cow-replacement costs. In order to control MAP in dairies with drylot pens, a standardized environmental sampling protocol to quantify MAP in fecal slurry was developed based on an existing protocol for freestall pens. Specifically, following a 24 h hold of the flush, a grab sample of approximately 10 ml of fecal slurry was collected every 1 m along the flush lane of the drylot pens, avoiding individual cow fecal pats. To determine the reliability and repatability of the new environmental sampling protocol for estimation of MAP bioburden at the pen level, two collectors simultaneously collected fecal slurry samples every day for 3 days from six drylot cow pens on two Central California dairies. During the study period no cow movement between pens was allowed with the exception of sick cows. The study herds had MAP seroprevalence of 5.8% and 3.2%, respectively, based on whole pen serum ELISA results. Variance components models for quantitative real-time PCR (qPCR) results showed samples collected from different pens on different dairies accounted for greater variablitiy in MAP concentration (65%), while samples collected by different collectors had the least variability (0.1%). In contrast, variability in MAP concentration in environmental samples collected on different days had 25% variability. The intraclass correlation coefficient showed high reliability (93%) of environmental sampling simultaneously by different collectors. In contrast, the reliability of environmental sampling at different days was 65%, which was similar to the reliability for sampling by different collectors on different days. Investigators can expect high reliability when employing the new environmental sampling protocol along with qPCR testing of environmental samples from drylot pens

Site-Specific Earthquake Ground Motions for the 12th Street and 14th Street Viaducts on Route 139 in Jersey City, New Jersey

The 12th and 14th Street Viaducts, which carry Route 139, are located west of the Holland Tunnel in Jersey City, New Jersey. The two viaducts, supported on pile foundations, provide access to and from the Holland Tunnel (which connects New York City and New Jersey) and are considered critical structures. The New Jersey Department of Transportation (NJDOT) has selected DMJM+HARRIS to perform design services including rehabilitation and seismic retrofit for the 12th Street and 14th Street Viaducts. The subsurface conditions play a major role in evaluating the structures behavior under a seismic event. At the project site, the subsurface conditions consist of the following six strata: Loose to Medium Dense Sand (Fill), Peat/Organic Silt, Normally Consolidated Silty Clay, Silt/Sand, Weathered Rock and Bedrock. The magnitude of the seismic event will influence the response of these soil strata. The purpose of this paper is to present the results of a site-specific earthquake ground motions on rock. A probabilistic seismic hazard analysis (PSHA) was developed for this site. In addition, the paper will also present the results of site response analysis performed to compute ground motions at footing level and their associated response spectra. Values of soil amplification between the spectral acceleration of the footing level and the bedrock response spectra will be calculated and presented. A comparison of the resulting data to the current design spectra as defined in the 1998 New York City Department of Transportation (NYCDOT) Seismic Design Guidelines is presented. In order to determine the effects of the site soils on bedrock motions, it was required to define a soil profile with layer thickness and dynamic soil properties. The dynamic soil properties for the soil profiles were derived using a correlation with shear wave velocities obtained from cross hole surveys and from a correlation with standard penetration tests. Fourteen (14) soil profiles with two hazard levels having a return period of 500 years (probability of exceedence of 10% in 50 years) and a return period of 2500 years (probability of exceedance of 2% in 50 years) will be compared to the NYCDOT Class C, D and E soil profiles, which are appropriate for this site. The site response spectra were developed for the two level seismic events, using the computer program SHAKE. Nonlinear soil behavior is approximated by equivalent linear techniques implemented in SHAKE

Wave Excitation in Disks Around Rotating Magnetic Stars

The accretion disk around a rotating magnetic star (neutron star, white dwarf or T Tauri star) is subjected to periodic vertical magnetic forces from the star, with the forcing frequency equal to the stellar spin frequency or twice the spin frequency. This gives rise bending waves in the disk that may influence the variabilities of the system. We study the excitation, propagation and dissipation of these waves using a hydrodynamical model coupled with a generic model description of the magnetic forces. The $m=1$ bending waves are excited at the Lindblad/vertical resonance, and propagate either to larger radii or inward toward the corotation resonance where dissipation takes place. While the resonant torque is negligible compared to the accretion torque, the wave nevertheless may reach appreciable amplitude and can cause or modulate flux variabilities from the system. We discuss applications of our result to the observed quasi-periodic oscillations from various systems, in particular neutron star low-mass X-ray binaries.Comment: Small changes/clarifications. To be published in ApJ, Aug.20,2008 issu