The Drained Strength of Bentonite Enhanced Sand

INTRODUCTION Barriers with a low hydraulic conductivity are used as part of waste containment systems to prevent groundwater contamination by liquids from the waste. Commonly barriers are either a geomembrane (usually an HDPE sheet), a mineral layer or a combination of the two. Recently there has been increasing interest in the use of bentonite±sand mixtures as the mineral layer, in both land®ll liners and vertical cut-off walls, partly because they are less susceptible to frost damage and desiccation cracking than compacted clay (Dixon et al., 1985; Kraus et al., 1997). Currently there is uncertainty about the strength and bearing capacity of these materials. This note reports drained strength data for bentonite±sand mixtures and proposes that trends in these data are mainly the result of variations in the relative density of the sand

Herramienta para caracterización de mecanismos nacionales de inspección de alimentos

El Instituto Interamericano de Cooperación para la Agricultura (IICA) preparó la presente “Herramienta para caracterización de mecanismos nacionales de inspección de alimentos” en el afán de contribuir a que sus Países Miembros eleven el nivel de desempeño de su mecanismo de inspección de alimentos, que son parte integral y central de sus servicios de control de inocuidad de alimentos

Caracterización de capacidades nacionales de respuesta a emergencias en sanidad animal y protección vegetal

Esta guía pretende poner a disposición de los países un método que les ayude a determinar su grado de preparación en caso de una emergencia sanitaria o fitosanitaria. Los resultados pueden ser utilizados para identificar las fortalezas y debilidades, definir qué es necesario mejorar áreas, seguimiento de los logros, modernizar los procedimientos y preparar proyectos para el fortalecimiento institucional.This guide aims to provide countries with a method to help them determine their level of preparedness in the event of a sanitary or phytosanitary emergency. The results can be used to identify strengths and weaknesses, define what areas need to be improved, monitor achievements, modernize procedures and prepare projects for institutional strengthening

Granuloma central de células gigantes: presentación

El Granuloma Central de Células Gigantes (GCCG), es una rara lesión no odontogénica y benigna, que prevalece en sexo femenino entre la segunda y tercera década de vida. Generalmente asintomático, en sus estadios iniciales es de crecimiento lento y al superar los 5 cm adquiere un comportamiento más agresivo. Presentamos un caso clínico en mandíbula, detallando su diagnóstico y tratamiento; y una revisión de la literatura.The Central Granuloma of Giant Cells (CGGC) is a rare non-odontogenic and benign lesion, which prevails in the female sex between the second and third decade of life. Generally, asymptomatic, in its initial stages it is slow growing and when it exceeds 5 cm it acquires a more aggressive behavior. We present a clinical case in the jaw, detailing its diagnosis and treatment, and a review of the literature.Facultad de Ciencias Médica

Time-Dependent Fatigue Crack Propagation Behavior of Two Solid-Solution-Strengthened Ni-Based Superalloys—INCONEL 617 and HAYNES 230

The fatigue crack propagation (FCP) as well as the sustained loading crack growth (SLCG) behavior of two solid-solution-strengthened Ni-based superalloys, INCONEL 617 (Special Metals Corporation Family of Companies) and HAYNES 230 (Haynes International, Inc., Kokomo, IN), were studied at increased temperatures in laboratory air under a constant stress-intensity- factor (K) condition. The crack propagation tests were conducted using a baseline cyclic triangular waveform with a frequency of 1 3 Hz. Various hold times were imposed at the maximum load of a fatigue cycle to study the hold time effect. The results show that a linear elastic fracture mechanics (LEFM) parameter, stress intensity factor (K), is sufficient to describe the FCP and SLCG behavior at the testing temperatures ranging from 873 K to 1073 K (600 C to 800 C). As observed in the precipitation-strengthened superalloys, both INCONEL 617 and HAYNES 230 exhibited the time-dependent FCP, steady SLCG behavior, and existence of a damage zone ahead of crack tip. A thermodynamic equation was adapted to correlate the SLCG rates to determine thermal activation energy. The fracture modes associated with crack propagation behavior were discussed, and the mechanism of time-dependent FCP as well as SLCG was identified. Compared with INCONEL 617, the lower crack propagation rates of HAYNES 230 under the time-dependent condition were ascribed to the different fracture mode and the presence of numerous W-rich M6C-type and Cr-rich M23C6-type carbides. Toward the end, a phenomenological model was employed to correlate the FCP rates at cycle/time-dependent FCP domain. All the results suggest that an environmental factor, the stress assisted grain boundary oxygen embrittlement (SAGBOE) mechanism, is mainly responsible for the accelerated time dependent FCP rates of INCONEL 617 and HAYNES 230

Granuloma central de células gigantes: presentación

El Granuloma Central de Células Gigantes (GCCG), es una rara lesión no odontogénica y benigna, que prevalece en sexo femenino entre la segunda y tercera década de vida. Generalmente asintomático, en sus estadios iniciales es de crecimiento lento y al superar los 5 cm adquiere un comportamiento más agresivo. Presentamos un caso clínico en mandíbula, detallando su diagnóstico y tratamiento; y una revisión de la literatura.The Central Granuloma of Giant Cells (CGGC) is a rare non-odontogenic and benign lesion, which prevails in the female sex between the second and third decade of life. Generally, asymptomatic, in its initial stages it is slow growing and when it exceeds 5 cm it acquires a more aggressive behavior. We present a clinical case in the jaw, detailing its diagnosis and treatment, and a review of the literature.Facultad de Ciencias Médica

Prisons for profit : America's crackdown on crime fuels a jailhouse boom. by Carl Mollins

As federal and state politicians impose laws and rules for tougher sentences and longer servitude before parole, the prison population expands explosively - and so do the costs of incarceration. One answer is to turn to the private sector

The Design of Bentonite-Sand Mixtures

One-dimensional and isotropic swelling tests, hydraulic conductivity tests and triaxial compression tests have been performed at applied stresses up to 450kPa on sodium bentonite powder, sand and compacted sodium bentonite-sand mixtures (5, 10, and 20% bentonite by dry weight). This was done to investigate the use of bentonite improved soils for waste containment, and study the fundamental geotechnical properties of bentonite-sand mixtures using a classical soil mechanics approach. It was found that air dried bentonite powder swells to reach a state described by a single straight line on a plot of void ratio against the logarithm of vertical effective stress, regardless of preparation technique. The gradient of this line was intermediate between a normal consolidation and rebound line for the same material indicating a different sample fabric when allowed to reach equilibrium from an initially dry state rather than the conventional fully saturated state. Swelling of bentonite-sand mixtures expressed in terms of the clay void ratio show a deviation from bentonite behaviour above a threshold stress which depends on the bentonite content. From this behaviour, a modified principle of effective stress has been proposed. Similar swelling relationships were found for samples under an isotropic confining stress. Hydraulic conductivity data for bentonite and mixtures indicate an approximately linear relationship between the logarithm of hydraulic conductivity and the logarithm of void ratio. Observed differences in hydraulic conductivity between bentonite and mixtures, when represented in terms of the clay void ratio, are attributed to the sand porosity and tortuosity. From a stress-dilatancy analysis of triaxial data, the peak strength of mixtures has been shown to depend on the sand relative density. This parameter indicates how the material will behave during shear. A threshold sand relative density has been postulated, which is dependent on the axial strain. Below the threshold value, it is likely that the stress-strain behaviour will be characteristic of the bentonite alone. A design model based on the clay void ratio, sand porosity and tortuosity, and sand relative density is presented, enabling the hydraulic conductivity or strength of a mixture to be estimated

The blind man's song

Gift of Dr. Mary Jane Esplen.Piano vocal [instrumentation]I lived all in darkness [first line]To this world I am blind [first line of chorus]F [key]Andante moderato [tempo]Albert Mollins (photograph) [illustration]No publisher's advertisement [note]This song composed by a blind man [note]On sale by Reliable Music Stores and through agents [note