The measurement of the optical absorption cross section of photosystem 1 and photosystem 2 from whole live cells of porphyridium cruentum, in light state 1 and light state 2

The optical cross section of PS I in whole cells of Porphyridium cruentum (UTEX 161), held in either state 1 or state 2, was determined by measuring the change in absorbance at 820nm, an indication of P700+; the X-section of PS2 was determined by measuring the variable fluorescence, (Fv-Fo)/Fo, from PS2. Both cross-sections were 7 determined by fitting Poisson distribution equations to the light saturation curves obtained with single turnover laser flashes which varied in intensity from zero to a level where maximum yield occurred. Flash wavelengths of 574nm, 626nm, and 668nm were used, energy absorbed by PBS, by PBS and chla, and by chla respectively. There were two populations of both PSi and PS2. A fraction of PSi is associated with PBS, and a fraction of PS2 is free from PBS. On the transition S1->S2, only with PBS-absorbed energy (574nm) did the average X-section of PSi increase (27%), and that of PS2 decrease (40%). The fraction of PSi associated with PBS decreased, from 0.65 to 0.35, and the Xsection of this associated PS 1 increased, from 135±65 A2 to 400±300A2. The cross section of PS2 associated with PBS decreased from 150±50 A2 to 85±45 A2, but the fraction of PS2 associated with PBS, approximately 0.75, did not change significantly. The increase in PSi cross section could not be completely accounted for by postulating that several PSi are associated with a single PBS and that in the transition to state2, fewer PSi share the same number of PBS, resulting in a larger X-section. It is postulated that small changes occur in the attachment of PS2 to PBS causing energy to be diverted to the attached PSi. These experiments support neither the mobile-PBS model of state transitions nor that of spillover. From cross section changes there was no evidence of energy transfer from PS2 to PSi with 668nm light. The decrease in PS2 fluorescence which occurred at this wavelength cannot be explained by energy transfer; another explanation must be sought. No explanation was found for an observed decrease in PSi yield at high flash intensities.

Turbines Plans - General Arrangement of Shaft & Cross Section of Turbine, 1903

Two photographs of turbine drawings from the year 1903. The first drawing is titled "10000HP Turbines. Canadian Niagara Power Company. General Arrangement of Shaft." It was last revised 18 May, 1903. The second drawing is titled "10000HP Turbines Canadian Niagara Power Company. Cross Section of Turbine" This drawing revised 6 May, 1903 and 26 June, 1903.

Second interim report of the Canadian section and first joint report of the International Waterways Commission (1906)

Report of the Canadian section, dated April 25th, 1906, and report of the joint commission, dated May 3d, 1906, related to regulating the uses of the waters of the Niagara River and the preservation of the Falls.

Canadian Niagara Power Glass Slide - Drawing: Section thru Wheelpit

Drawing of "Section thru Wheelpit" dated September 1925. Shows unit no.1 through unit no.11, power house floor and water surface.

HG 186.15-186.25 Thin Section

Coarse grained sample with multiple fine grained domains. Clasts range from small to medium and sub-angular to sub-rounded. Mainly contains grain crushing (with grains crushed into one another) and short distance lineations. A few rotation structures are seen and fine grained sand domains can also be seen.

HG 186.80-186.85 Thin section

A coarse grained sample with clay rich domains. Grains range from small to medium and are sub-angular. Rotation structures can be seen around sub-rounded clasts. Lineations can be seen throughout the image, mainly short distance lineations. Small comet structures can also be seen throughout the images.

HG 186.9-187.0 D.E. Thin Section

Coarse grained sample with grains varying from small to medium in size. They range from sub-angular to sub-rounded in shape. The sample is abundant in lineations and comet structures. Minor amounts of grain stacking are present. Inclusions of a clay rich, fine grained domain.

HG 187.45-187.65 Thin Section

Coarse grained sediment with fine grained domains throughout. The clasts in the coarse grained domain range from sub-angular to sub-rounded. Short distance lineations are present throughout the sample. Organic rich domains (darker) are prevalent alongside fractured grains.

HG 188.60-188.70 Thin Section

Dark brown sediment with mainly small grains. Clasts are sub-angular. Abundant in lineations, grain stacking, and minor grain crushing. Lineations are oriented in multiple directions.

HG 195.45-195.55 Thin Section

Dark brown sediment with clasts ranging from small to large. The grains are sub-angular. Two main domains can be seen. Both are coarse grained, but one contains larger grains and potentially more clay material. Lineations are present throughout the sample in multiple directions. Minor rotation around a few larger clasts can be seen, as well as comet structures.

HG 196.20-196.30 Thin Section

Brown, coarse grained sediment , with clay material. Clasts range from small to large, and sub-angular to sub-rounded. Organic material can be seen. Lineations are abundant. Grain stacking edge-to-edge grain crushing can also be seen. Organic material can be seen. Edge-to-edge grain crushing is seen throughout the image. Contains the inclusion of a finer domain.

HG 198.20-198.35 Thin Section

Coarse grained brown sediment with angular-sub-angular grains. Contains mainly medium sized clasts with a few smaller aggregates. A dark organic rich domain can be seen within this sample. Grain crushing (edge-to-edge and into one another) can be seen alongside with grain stacks, and silt caps.

HG 206.85-206.95 Thin Section

Coarse grained sample with sub-angular to sub-rounded clasts. Clasts range from small to medium sized. Major grain crushing seen throughout the sample. Grain stacking and lineations are also present. A dark organic rich domain can be seen within the sample.

HG 215.65-215.75 Thin Section

Brown to dark brown sediment with small to medium sized clasts ranging from sub-angular to sub-rounded. This sample contains a coarse grained domain and a fine grained domain. Clear boundaries can be seen. Grain stacking can be seen in the coarse domain, while lineations are the dominant microstructure in the fine grained domain. Minor grain crushing can also be seen. Some of the coarser domain is rich in clay and organics.