8 resultados para ROOT CANALS

em Brock University, Canada


Relevância:

20.00% 20.00%

Publicador:

Resumo:

A study has been conducted focusing on how the phosphorus renrx)val efficiency of a constructed wetland (CW) can be optimized through the selective enrichment of the substratum. Activated alumina and powdered iron were examined as possible enrichment compounds. Using packed glass column trials it was found that alumina was not suitable for the renx)val of ortho-phosphate from solution, while mixtures of powdered iron and quartz sand proved to be very efficient. The evaluation of iron/sand mixtures in CWs planted with cattails was performed in three stages; first using an indoor lab scale wetland, then an outdoor lab scale wetland, and finally in a small scale pilot project. For the lab scale tests, three basic configurations were evaluated: using the iron/sand as a pre-filter, in the root bed. and as a post filter. Primary lagoon effluent was applied to the test cells to simulate actual CW conditions, and the total phosphorus and iron concentrations of the influent and effluent were nfK)nitored. The pilot scale trials were limited to using only a post filter design, due to in-progress research at the pilot site. The lab scale tests achieved average renrK>val efficiencies greater than 91% for all indoor configurations, and greater than 97% for all outdoor configurations. The pilot scale tests had an average renK)val efficiency of 60%. This relatively low efficiency in the pilot scale can be attributed to the post filters being only one tenth the size of the lab scale test in terms of hydraulic loading (6 cm/day vs. 60 cm/day).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A simple method was developed for treating corn seeds with oxamyl. It involved soaking the seeds to ensure oxamyl uptake, centrifugation to draw off excess solution, and drying under a stream of air to prevent the formation of fungus. The seeds were found to have an even distribution of oxamyl. Seeds remained fungus-free even 12 months after treatment. The highest nonphytotoxic treatment level was obtained by using a 4.00 mg/mL oxamyl solution. Extraction methods for the determination of oxamyl (methyl-N'N'-dimethyl-N-[(methylcarbamoyl)oxy]-l-thiooxamimidate), its oxime (methyl-N',N'-dimethyl-N-hydroxy-1-thiooxamimidate), and DMCF (N,N-dimethyl-1-cyanoformanade) in seed" root, and soil were developed. Seeds were processed by homogenizing, then shaking in methanol. Significantly more oxamyl was extracted from hydrated seeds as opposed to dry seeds. Soils were extracted by tumbling in methanol; recoveries range~ from 86 - 87% for oxamyl. Root was extracted to 93% efficiency for oxamyl by homogenizing the tissue in methanol. NucharAttaclay column cleanup afforded suitable extracts for analysis by RP-HPLC on a C18 column and UV detection at 254 nm. In the degradation study, oxamyl was found to dissipate from the seed down into the soil. It was also detected in the root. Oxime was detected in both the seed and soil, but not in the root. DMCF was detected in small amounts only in the seed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The effect that plants {Typha latifolia) as well as root-bed medium physical and chemical characteristics have on the treatment of primary treated domestic wastewater within a vertical flow constructed wetland system was investigated. Five sets of cells, with two cells in each set, were used. Each cell was made of concrete and measured 1 .0 m X 1 .0 m and was 1.3 m deep. Four different root-bed media were tested : Queenston Shale, Fonthill Sand, Niagara Shale and a Michigan Sand. Four of the sets contained plants and a single type of root-bed medium. The influence of plants was tested by operating a Queenston Shale set without plants. Due to budget constraints no replicates were constructed. All of the sets were operated independently and identically for twenty-eight months. Twelve months of data are presented here, collected after 16 months of continuous operation. Root-bed medium type did not influence BOD5 removal. All of the sets consistently met Ontario Ministry of Environment (MOE) requirements (<25 mg/L) for BOD5 throughout the year. The 12 month average BOD5 concentration from all sets with plants was below 2.36 mg/L. All of the sets were within MOE discharge requirements (< 25 mg/L) for suspended solids with set effluent concentrations ranging from 1.53 to 14.80 mg/L. The Queenston Shale and Fonthill Sand media removed the most suspended solids while the Niagara Shale set produced suspended solids. The set containing Fonthill Sand was the only series to meet MOE discharge requirements (< Img/L) for total phosphorus year-round with a twelve month mean effluent concentration of 0.23 mg/L. Year-round all of the root-bed media were well below MOE discharge requirements (< 20mg/L in winter and < 10 mg/L in sumnner) for ammonium. The Queenston Shale and Fonthill Sand sets removed the most total nitrogen. Plants had no effect on total nitrogen removal, but did influence how nitrogen was cycled within the system. Plants increased the removal of suspended solids by 14%, BOD5 by 10% and total phosphorus by 22%. Plants also increased the amount of dissolved oxygen that entered the system. During the plant growing season removal of total phosphorus was better in all sets with plants regardless of media type. The sets containing Queenston Shale and Fonthill Sand media achieved the best results and plants in the Queenston Shale set increased treatment efficiency for every parameter except nitrogen. Vertical flow wetland sewage treatment systems can be designed and built to consistently meet MOE discharge requirements year-round for BOD5, suspended solids, total phosphorus and ammonium. This system Is generally superior to the free water systems and sub-surface horizontal flow systems in cold climate situations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Welland Canals Society was a coalition of business, tourism, heritage, and recreational groups that joined with the Regional Government in 1986 to promote the redevelopment of the Welland Canals Corridor. The mandate of the Society was to provide leadership and assistance to the public and private sectors in achieving heritage-sensitive and tourism/recreation-related economic development in the Welland Canals Corridor. The Society folded in 1991 due to government funding cuts.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

‘The Father of Canadian Transportation’ is a term commonly associated with William Hamilton Merritt. Although he is most known for being one of the driving forces behind the building of the first Welland Canal, he was many things throughout his life; a soldier, merchant, promoter, entrepreneur and politician to name a few. Born on July 3, 1793 at Bedford, Westchester County, N.Y. to Thomas Merritt and Mary Hamilton, Merritt’s family relocated to Canada shortly after in 1796. The move came after Merritt’s father petitioned John Graves Simcoe for land in Upper Canada after serving under him in the Queen’s Rangers during the American Revolution. The family quickly settled into their life at Twelve Mile Creek in St. Catharines. Merritt’s father became sheriff of Lincoln County in 1803 while Merritt began his education in mathematics and surveying. After some brief travel and further education Merritt returned to Lincoln County, in 1809 to help farm his father’s land and open a general store. While a farmer and merchant, Merritt turned his attention to military endeavours. A short time after being commissioned as a Lieutenant in the Lincoln militia, the War of 1812 broke out. Fulfilling his duty, Merritt fought in the Battle of Queenston Heights in October of 1812, and numerous small battles until the Battle of Lundy’s Lane in July 1814. It was here that Merritt was captured and held in Cheshire, Massachusetts until the war ended. Arriving back in the St. Catharines area upon his release, Merritt returned to being a merchant, as well as becoming a surveyor and mill owner. Some historians hypothesize that the need to draw water to his mill was how the idea of the Welland Canals was born. Beginning with a plan to connect the Welland River with the Twelve mile creek quickly developed into a connection between the Lakes Erie and Ontario. Its main purpose was to improve the St. Lawrence transportation system and provide a convenient way to transport goods without having to go through the Niagara Falls portage. The plan was set in motion in 1818, but most living in Queenston and Niagara were not happy with it as it would drive business away from them. Along with the opposition came financial and political restraints. Despite these factors Merritt pushed on and the Welland Canal Company was chartered by the Upper Canadian Assembly on January 19, 1824. The first sod was turned on November 30, 1824 almost a year after the initial chartering. Many difficulties arose during the building of the canal including financial, physical, and geographic restrictions. Despite the difficulties two schooners passed through the canal on November 30, 1829. Throughout the next four years continual work was done on the canal as it expended and was modified to better accommodate large ships. After his canal was underway Merritt took a more active role in the political arena, where he served in various positions throughout Upper Canada. In 1851, Merritt withdrew from the Executive Council for numerous reasons, one of which being that pubic interest had diverted from the canals to railways. Merritt tried his hand at other public works outside transportation and trade. He looked into building a lunatic asylum, worked on behalf of War of 1812 veterans, aided in building Brock’s monument, established schools, aided refugee slaves from the U.S. and tried to establish a National Archives among many other feats. He was described by some as having “policy too liberal – conceptions too vast – views too comprehensive to be comprehensible by all”, but he still made a great difference in the society in which he lived. After his great contributions, Merritt died aboard a ship in the Cornwall canal on July 5, 1862. Dictionary of Canadian Biography Online http://www.biographi.ca/EN/ShowBio.asp?BioId=38719 retrieved October 2006 Today numerous groups carry on the legacy of Merritt and the canals both in the past and present. One such group is the Welland Canals Foundation. They describe themselves as: “. . . a volunteer organization which strives to promote the importance of the present and past Welland Canals, and to preserve their history and heritage. The Foundation began in 1980 and carries on events like William Hamilton Merritt Day. The group has strongly supported the Welland Canals Parkway initiative and numerous other activities”. The Welland Canals Foundation does not work alone. They have help from other local groups such as the St. Catharines Historical Society. The Society’s main objective is to increase knowledge and appreciation of the historical aspects of St. Catharines and vicinity, such as the Welland Canals. http://www.niagara.com/~dmdorey/hssc/dec2000.html - retrieved Oct. 2006 http://www.niagara.com/~dmdorey/hssc/feb2000.html - retrieved Oct. 2006

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Abstract: Root and root finding are concepts familiar to most branches of mathematics. In graph theory, H is a square root of G and G is the square of H if two vertices x,y have an edge in G if and only if x,y are of distance at most two in H. Graph square is a basic operation with a number of results about its properties in the literature. We study the characterization and recognition problems of graph powers. There are algorithmic and computational approaches to answer the decision problem of whether a given graph is a certain power of any graph. There are polynomial time algorithms to solve this problem for square of graphs with girth at least six while the NP-completeness is proven for square of graphs with girth at most four. The girth-parameterized problem of root fining has been open in the case of square of graphs with girth five. We settle the conjecture that recognition of square of graphs with girth 5 is NP-complete. This result is providing the complete dichotomy theorem for square root finding problem.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The soil-inhabiting insect-pathogenic fungus Metarhizium robertsii also colonizes plant roots endophytically, thus showing potential as a plant symbiont. M robertsii is not randomly distributed in soils but preferentially associates with the plant rhizosphere when applied in agricultural settings. Root surface and endophytic colonization of switchgrass (Panicum virgatum) and haricot beans (Phaseolus vulgaris) by M robertsii were examined after inoculation with fungal conidia. Light and confocal microscopies were used to ascertain this rhizosphere association. Root lengths, root hair density and emergence of lateral roots were also measured. Initially, M robertsii conidia adhered to, germinated on, and colonized, roots. Furthermore, plant roots treated with Metarhizium grew faster and the density of plant root hairs increased when compared with control plants. The onset of plant root hair proliferation was initiated before germination of M robertsii on the root (within 1-2 days). Plants inoculated with M robertsii AMAD2 (plant adhesin gene) took significantly longer to show root hair proliferation than the wild type. Cell free extracts of M robertsii did not stimulate root hair proliferation. Longer term (60 days) associations showed that M robertsii endophytically colonized individual cortical cells within bean roots. Metarhizium appeared as an amorphous mycelial aggregate within root cortical cells as well as between the intercellular spaces with no apparent damage to the plant. These results suggested that not only is M robertsii rhizosphere competent but displays a beneficial endophytic association with plant roots that results in the proliferation of root hairs. The biocontrol of bean (Phaseolis vulgaris) root rot fungus Fusarium solani f. sp. phaseolis by Metarhizium robertsii was investigated in vitro and in vivo. Dual cultures on Petri dishes showed antagonism of M robertsii against F. solani. A relative inhibition of ca. 60% of F. solani growth was observed in these assays. Cell free culture filtrates of M robertsii inhibited the germination of F. solani conidia by 83% and the inhibitory metabolite was heat stable. Beans plants colonized by M robertsii then exposed to F. solani showed healthier plant profiles and lower disease indices compared to plants not colonized by M robertsii. These results suggested that the insect pathogenic/endophytic fungus M robertsii could also be utilized as a biocontrol agent against certain plant pathogens occurring in the rhizosphere.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This copy is signed in the upper left hand corner by Mr. Dickson. Mr. Robert Dickson was one of the directors of the Welland Canal Office. The report covers meetings which were held: January 15-16, and 19 of 1830. The meetings were attended by Messrs. Blacklock, Mackenzie, Woodruff, Longley and Hopkins. Balance sheets are also included within the report. The report of the Welland Canal Company for 1829 is also included within this document, and this is dated December 31, 1829. Names at the end of the 1929 report are members of the Welland Canal Office and they include: John Henry Dunn, president; Henry J. Boulton, vice-president and William Allan, George Keefer, John J. Lefferty and Robert Dickson who were directors The report is dated January 26, 1830, and submitted by Thomas Horner, chairman of the Commons House of Assembly.