6 resultados para COULOMB STAIRCASE
em Brock University, Canada
Resumo:
Four staircase lakes occupying a single watershed located in the Algoma District, north of Lake Superior were chosen for this study. I examined the subfossil diatom assemblage in the top twenty centimeters of the surface sediments in each of these four lakes in an attempt to reconstruct their respective past pH history. From these analyses it was possible to test the hypothesis that the rate of change of diatom inferred pH was not significantly different in lakes located one below the other in a single "staircase" within a single watershed system. My results indicated that the four Z lakes had been acid for at least the last century. The water color of the three upper Z lakes (Z1, Z2 and Z3) was brown (>30 Pt Co units). The bottom lake (Z4) was the only clear water lake in the system «5 Pt Co units). This bottom staircase lake had no muskeg development around its shoreline. The alkaliphilous diatoms in the Z watershed system were important in determining the diatom inferred pH of the four Z lakes. The centric diatoms were extremely rare in the clearwater bottom lake (Z4). The ecology of the Eupodiscales is perhaps important in the interpretation of sediment in the more acid environment. Lake Z4 was the only one that had a progressive as well as a significant decrease in its downcore diatom inferred pH since the early 1960's. This lead me to speculate that the humic substances present in the upper three brown water lakes (Z1, Z2 and Z3) were perhaps Important in buffering them against a further decrease in water pH even though they were located within an area which was sensitive to acid precipitation.
Resumo:
Black and white photographs, 19 cm x 24 cm of the interior of an unidentified house showing the staircase and landing, looking down a hallway to an exterior door. The photograph was taken by Wurts Brothers General Photographers of New York City (2 copies).
Resumo:
The algebraic expressions for the anharmonic contributions to the Debye-Waller factor up to 0(A ) and 0 L% ) £ where ^ is the scattering wave-vector] have been derived in a form suitable for cubic metals with small ion cores where the interatomic potential extends to many neighbours. This has been achieved in terms of various wave-vector dependent tensors, following the work of Shukla and Taylor (1974) on the cubic anharmonic Helmholtz free energy. The contribution to the various wave-vector dependent tensors from the coulomb and the electron-ion terms in the interatomic metallic potential has been obtained by the Ewald procedure. All the restricted multiple whole B r i l l o u i n zone (B.Z.) sums are reduced to single whole B.Z. sums by using the plane wave representation of the delta function. These single whole B.Z. sums are further reduced to the •%?? portion of the B.Z. following Shukla and Wilk (1974) and Shukla and Taylor (1974). Numerical calculations have been performed for sodium where the Born-Mayer term in the interatomic potential has been neglected because i t is small £ Vosko (1964)3 • *n o^er to compare our calculated results with the experimental results of Dawton (1937), we have also calculated the r a t io of the intensities at different temperatures for the lowest five reflections (110), (200), (220), (310) and (400) . Our calculated quasi-harmonic results agree reasonably well with the experimental results at temperatures (T) of the order of the Debye temperature ( 0 ). For T » © ^ 9 our calculated anharmonic results are found to be in good agreement with the experimental results.The anomalous terms in the Debye-Waller factor are found not to be negligible for certain reflections even for T ^ ©^ . At temperature T yy Op 9 where the temperature is of the order of the melting temperature (Xm) » "the anomalous terms are found to be important almost for all the f i ve reflections.
Resumo:
In 1818 Parkhurst Whitney built stairs leading to the river’s edge at Prospect Point. In 1825 Porter Brother replaced that staircase with a spiral one. In 1844 Whitney started a water powered incline railway there although the staircase was also used until 1890. In 1906 the water wheel was replaced by an electric power plant. There were lower buildings which included Shadow of the Rock which was a concession stand and also rented raincoats to the tourists. This was destroyed by fire and ice in 1892 and replaced by a chalet-style building in 1894-95. On July 6th, 1907 a cable on the incline railway broke. One person was killed and several sustained injuries. An elevator was constructed and it opened in January of 1910. It was condemned in 1954 when water entered the shaft, this was at the time of the collapse of Prospect Point which occurred at 4:50 pm. on July 28, 1954. This photograph was taken prior to 1954. Today the New York State Observation Tower stands at Prospect Point and The Maid of the Mist boat ride is available from the base of the tower. with information from: Niagara Falls Canada: a History by the Kiwanis Club of Stamford, Ontario
Resumo:
Brock’s Monument is owned by Parks Canada and maintained by the Niagara Parks Commission in collaboration with the Friends of Fort George and Niagara National Historic Sites. It is located in Queenston Heights Park atop the Niagara Escarpment. On March 14, 1815, Parliament passed an act to erect a monument to the memory of General Isaac Brock. A design by engineer Francis Hall was selected. He envisioned a 135 ft. tall Tuscan column, made out of stone with a winding staircase inside. By the spring of 1824, work had begun on the monument. In June of that year, the cornerstone was laid and William Lyon Mackenzie was in attendance at the ceremony. It was on October 13th, 1824 (the anniversary of Brock’s death) that 6000 people traveled to Queenston to inter the remains of Brock and Lieutenant-Colonel Macdonell. This was the second burial for both. After 3 years the tower had reached 135 feet, but there was no inscription at the base, the fence around the observation deck had not been installed and there was no statue of Brock. Hall submitted a plan to finish the statue, but he was turned down and a simple ornament was placed where the Brock statue should have been. A massive blast of gunpowder destroyed the monument in 1840. It is alleged that an American sympathizer with the Upper Canada Rebellion set off the blast. Brock and Macdonell’s bodies were reburied in the Hamilton Family Cemetery in Queenston. The present monument was rebuilt in 1853. William Thomas (designer of St. Michael’s Cathedral in Toronto) was the architect. Brock and Macdonell were once again laid to rest in separate vaults at the statue. In 1968, Brock’s Monument was declared a national historical site. In 2005, it was closed to the public due to safety concerns, but it reopened in 2010. Source: http://www.thecanadianencyclopedia.com/articles/brocks-monument-queenston-heights
Resumo:
Activated by elevations in myoplasmic calcium concentration, myosin light chain kinase (skMLCK) phosphorylates the regulatory light chains (RLCs) of fast muscle myosin. This covalent modification potentiates force production, but requires an investment of ATP. Our objective was to investigate the effect of RLC phosphorylation on the contractile economy (mechanical output:metabolic input) of fast twitch skeletal muscle. Extensor digitorum longus muscles isolated from Wildtype and skMLCK-/- mice mounted in vitro (25°C) were subjected to repetitive low-frequency stimulation (10Hz,15s) known to cause activation of skMLCK, and staircase potentiation of force. With a 3-fold increase in RLC phosphate content, Wildtype generated 44% more force than skMLCK-/- muscles over the stimulation period (P = .002), without an accompanied increase in energy cost (P = .449). Overall, the contractile economy of Wildtype muscles, with an intact RLC phosphorylation mechanism, was 73% greater than skMLCK /- muscles (P = .043), demonstrating an important physiological function of skMLCK during repetitive contractile activity.