Fuzzy logic power system stabilizer in multimachine stability studies

Power system stabilizers (PSS) work well at the particular network configuration and steady state conditions for which they were designed. Once conditions change, their performance degrades. This can be overcome by an intelligent nonlinear PSS based on fuzzy logic. Such a fuzzy logic power system stabilizer (FLPSS) is developed, using speed and power deviation as inputs, and provides an auxiliary signal for the excitation system of a synchronous motor in a multimachine power system environment. The FLPSS's effect on the system damping is then compared with a conventional power system stabilizer's (CPSS) effect on the system. The results demonstrate an improved system performance with the FLPSS and also that the FLPSS is robust

Controller structure and design of firing angle controllers for (unit connected) HVDC systems

This paper investigates the control of a HVDC link, fed from an AC source through a controlled rectifier and feeding an AC line through a controlled inverter. The overall objective is to maintain maximum possible link voltage at the inverter while regulating the link current. In this paper the practical feedback design issues are investigated with a view of obtaining simple, robust designs that are easy to evaluate for safety and operability. The investigations are applicable to back-to-back links used for frequency decoupling and to long DC lines. The design issues discussed include: (i) a review of overall system dynamics to establish the time scale of different feedback loops and to highlight feedback design issues; (ii) the concept of using the inverter firing angle control to regulate link current when the rectifier firing angle controller saturates; and (iii) the design issues for the individual controllers including robust design for varying line conditions and the trade-off between controller complexity and the reduction of nonlinearity and disturbance effects

Variation in the hindgut microbial communities of the Florida manatee, Trichechus manatus latirostris over winter in Crystal River, Florida

The Florida manatee, Trichechus manatus latirostris, is a hindgut-fermenting herbivore. In winter, manatees migrate to warm water overwintering sites where they undergo dietary shifts and may suffer from cold-induced stress. Given these seasonally induced changes in diet, the present study aimed to examine variation in the hindgut bacterial communities of wild manatees overwintering at Crystal River, west Florida. Faeces were sampled from 36 manatees of known sex and body size in early winter when manatees were newly arrived and then in mid-winter and late winter when diet had probably changed and environmental stress may have increased. Concentrations of faecal cortisol metabolite, an indicator of a stress response, were measured by enzyme immunoassay. Using 454-pyrosequencing, 2027 bacterial operational taxonomic units were identified in manatee faeces following amplicon pyrosequencing of the 16S rRNA gene V3/V4 region. Classified sequences were assigned to eight previously described bacterial phyla; only 0.36% of sequences could not be classified to phylum level. Five core phyla were identified in all samples. The majority (96.8%) of sequences were classified as Firmicutes (77.3 ± 11.1% of total sequences) or Bacteroidetes (19.5 ± 10.6%). Alpha-diversity measures trended towards higher diversity of hindgut microbiota in manatees in mid-winter compared to early and late winter. Beta-diversity measures, analysed through permanova, also indicated significant differences in bacterial communities based on the season.

Graenum Berger papers, undated, (1825)-2002

Contains correspondence, minutes, reports, clippings, manuscripts, research materials, journal articles, photographs and publications; primarily relating to Berger's involvement with Ethiopian Jewry and his efforts to bring about their rescue through the organization he formed, the American Association for Ethiopian Jews. Also contains material from Berger's other interests- his writings, travels through the world and to Israel and Ethiopia, community affiliations, research in Black American Jews, profession as a Jewish social work executive, his commitment to Jewish causes and to Israel. There are also many personal and biographical materials from the numerous long-term friendships and associations he established.

Solar coronal magnetic fields derived using seismology techniques applied to omnipresent sunspot waves

Sunspots on the surface of the Sun are the observational signatures of intense manifestations of tightly packed magnetic field lines, with near-vertical field strengths exceeding 6,000 G in extreme cases1. It is well accepted that both the plasma density and the magnitude of the magnetic field strength decrease rapidly away from the solar surface, making high-cadence coronal measurements through traditional Zeeman and Hanle effects difficult as the observational signatures are fraught with low-amplitude signals that can become swamped with instrumental noise2, 3. Magneto-hydrodynamic (MHD) techniques have previously been applied to coronal structures, with single and spatially isolated magnetic field strengths estimated as 9–55 G (refs 4,5,6,7). A drawback with previous MHD approaches is that they rely on particular wave modes alongside the detectability of harmonic overtones. Here we show, for the first time, how omnipresent magneto-acoustic waves, originating from within the underlying sunspot and propagating radially outwards, allow the spatial variation of the local coronal magnetic field to be mapped with high precision. We find coronal magnetic field strengths of 32 ± 5 G above the sunspot, which decrease rapidly to values of approximately 1 G over a lateral distance of 7,000 km, consistent with previous isolated and unresolved estimations. Our results demonstrate a new, powerful technique that harnesses the omnipresent nature of sunspot oscillations to provide magnetic field mapping capabilities close to a magnetic source in the solar corona.

Sketch of the ship "Jane C. Woodruff"

A black and white copy of a sketch of the ship "Jane C. Woodruff". This appears to have been in a scrapbook. There is a slight tear which affects the picture slightly. [The Jane C. Woodruff was a barquentine ship built in St. Catharines in 1866 by Lewis Shikeluna. The ship belonged to John Battle who was an associate of Samuel D. Woodruff. She was named in honour of Samuel and his wife, Jane Caroline. She originated as a square timber trade boat before being converted into a 3 masted schooner. She collided with the "Mary Battle" in a snow squall in Georgian Bay. The ship passed out of existence in 1902].

List of Voters for the Town of St. Catharines, 1874

A paperback "List of Voters for the Town of St. Catharines, 1874" by Journal Steam Print. Richard Woodruff is listed as an owner on St. Paul Street in St. Thomas' Ward (p.8) and Samuel D. Woodruff is also listed as an owner in St. Thomas' Ward (p.8). Richard Woodruff is listed as an owner in St. George's War (p.16). There is an extra front cover included which is badly wrinkled and stained. There is a handwritten list within the back of the book which tallies the number of people in each ward.

Mallard Duck Feathers

These feathers are enclosed in an envelope which has "Sam D. Woodruff, Water Commissioner, City" written on the front.

Cemetery Sketches

Crudely drawn sketches including: Samuel D. Woodruff’s grave; a sketch which includes the inside of the [St. George’s] church; Lot no. 4 and Woodruff and Milton graves. One of the maps was dated Dec. 31, 1871, n.d.

List of Records of Deeds for Graves, St. Catharines

1 handwritten list of records of deeds for graves in the public cemetery of St. Catharines including: Deed no.133 between the Rector of St. George’s Church in St. Catharines and Samuel DeVeaux Woodruff for 480 square feet in section P. Deed no. 134 between the Rector and church wardens of St. George’s Church and Anne S. Sanderson for 208 square feet in section P and Deed no. 1235 between the City Council of St. Catharines and Samuel D. Woodruff for 336 square feet in section P, 1861, 1883.

Letter to Mr. Joseph Woodruff

Letter to Mr. Joseph Woodruff stating that the affidavit which was taken by him [Joseph Woodruff] over a year since of Richard and William Woodruff attesting to the death of Richard Clement and of James Duffin Cleveland for Lot no.30, Concession 2 of Enniskillen was held by Mr. Thomas Bell and agents. All of his papers were consumed by a fire. The writer asks for a new form to be drawn. [The letter is unsigned but is from Port Robinson and most likely written by Samuel D. Woodruff], Dec. 4, 1848.

Letter to Mr. Thomas Bell

Letter to Mr. Thomas Bell asking him to use all due diligence to bring this claim before the committee. [This letter is unsigned but is from Port Robinson and likely written by Samuel D. Woodruff], Dec. 15, 1848.

Letter from Port Robinson to Mr. Bell

Letter from Port Robinson to Mr. Bell acknowledging the receipt for the affidavits which were sent. The writer says that he is not the owner of the land as Mr. Bell supposes. The writer is anxious for this matter to be brought before the committee and says that this matter has been 2 years in Mr. Steer’s hands in neglect. [The letter is unsigned, but the writer is probably Samuel D. Woodruff], April 10, 1849.

Telegram from Montreal and Dominion Telegraph Companies’ Lines form with a note on it saying “will wait for receipt”

Telegram from Montreal and Dominion Telegraph Companies’ Lines form with a note on it saying “will wait for receipt”[ no sender nor receiver listed, most likely Louis Cabot to Samuel D. Woodruff], 1886.