The main technical challenge of OTEC is to generate significant amounts of power efficiently from small temperature differences. small-scale OTEC plants can be made to accommodate the electricity production of small communities (5 000-50 000 residents), but would require the production of valuable by-products like fresh water or cooling to be economically viable. Method and Apparatus for Flash Evaporation of Liquids. Currently operating pilot-scale OTEC plants are located in Japan, overseen by Saga University, and Makai in Hawaii. **Vital Signs** [40], Besides water temperature, microbial fouling also depends on nutrient levels, with growth occurring faster in nutrient rich water. The location of this cline is dependent on its geographical position, seasonal weather patterns, turbulent water conditions, state mixing, and surface wind shear. TR-253-3616. There is no marine flora here, although certain bioluminescent species of fish are here (such as the angler fish). The location of the case of study was the Dutch Kingdom related island Curaao. In some schemes, the expanding vapor drives a low-pressure turbine attached to an electrical generator. The USGS works to understand Earth's history, past climate conditions, and to forecast climate change impacts. Below the thermocline lies the abyssal region of the oceans, where the temperature is much lower and variability generally much weaker than in the upper ocean. This was based on the results from a small scale aquaculture facility at the island of St Croix that used a deepwater supply line to feed the aquaculture basins. The thermocline divides warmer water above it and the colder water below. Productivity varies with the season and also locally and globally. b {\displaystyle {\dot {M_{T}}}={\frac {\mathrm {turbine} \ \mathrm {work} \ \mathrm {required} }{W_{T}}}}, Warm water mass flow rate, k Also, the water above the cline is often turbulent and in a mixed state, while the thermocline keeps the water below it calm. OTEC plants could be perceived as either a threat or potential partner to fisheries or to seabed mining operations controlled by the International Seabed Authority. THANKSFOR70K2023 - Redeem code for +3 . System analysis indicates that a 2-megawatt plant could produce about 4,300 cubic metres (150,000cuft) of desalinated water each day. OTEC can also supply quantities of cold water as a by-product. Like other clines, thermoclines can be found in a variety of areas. Which type of sea water has the greatest density? A) higher latitudes B) lower latitudes C) both high and low ie. The thrust force is then calculated by finding out the resistance forces. Minerals and nutrients can also be a retarding factor based on location of the oceans.So there will be less productivity than land which is 170 billion tons compared to 55 billion tons ion oceans. After most of the steam has been condensed by spout condensers, the non-condensible gas steam mixture is passed through a counter current region which increases the gas-steam reaction by a factor of five. Moreover, since there is no sunlight, they are almost transparent (lack of sunlight begins to bleach their skin until it becomes almost clear). An official website of the United States government. The condensate is then compressed to the highest pressure in the cycle, requiring condensate pump work, WC. Although they occupy just fewer than two percent of the surface of the oceans the large coastal upwelling areas on the eastern edges of the Pacific and the Atlantic are among the most biologically productive marine areas of all. [112][113], Worldmap highlighting oceanic regions with high, Variation of ocean temperature with depth, Parasitic power consumption by exhaust compressor, Lewis, Anthony, et al. Note, not all sperm whales can swim into the bathypelagic zone. Earth's ocean and climate are intrinsically connected and heavily influence one another in many ways. Finney, Karen Anne. The article or images cannot be reproduced, copied, shared or used in any form without the permission of the author and Marine Insight. During the summer, warm water, which is less dense, will sit on top of colder, denser, deeper water with a thermocline separating them. This is because these parameters vary widely over the oceans depth, and require different evolutionary systems to survive. The major additional parasitic energy requirements in the OTEC plant are the cold water pump work, WCT, and the warm water pump work, WHT. = Ocean Thermal Energy Corporation (OTE) currently[when?] Deep water currents are part of the global circulation of the Earth's ocean. Too much carbon dioxide in the ocean causes a problem called ocean acidification. Below this mixed layer, the temperature remains relatively stable over day/night cycles. A. stratosphere B. thermosphere C. mesosphere D . This pressure drop, which depends on the types of heat exchangers used, must be considered in final design calculations but is ignored here to simplify the analysis. They develop external coats of fat and scales to keep them warm and insulated. Due to the weather conditions, a warmer region known as the epilimnion exists above the cline, which is above the colder region known as the hypolimnion. 13. Deep-ocean Assessment and Reporting of Tsunamis, North West Shelf Operational Oceanographic System, Jason-2 (Ocean Surface Topography Mission), Cleaning and disinfection of personal diving equipment, Swimming at the 1900 Summer Olympics Men's underwater swimming, Confdration Mondiale des Activits Subaquatiques, Fdration Franaise d'tudes et de Sports Sous-Marins, Comando Raggruppamento Subacquei e Incursori Teseo Tesei, Namibian Marine Corps Operational Diving Unit, US Marine Corps Reconnaissance Battalions, Underwater Offence (Turkish Armed Forces), International Marine Contractors Association, Federacin Espaola de Actividades Subacuticas, International Association for Handicapped Divers, Environmental impact of recreational diving, Use of breathing equipment in an underwater environment, Failure of diving equipment other than breathing apparatus, Testing and inspection of diving cylinders, Association of Diving Contractors International, List of signs and symptoms of diving disorders, European Underwater and Baromedical Society, National Board of Diving and Hyperbaric Medical Technology, Naval Submarine Medical Research Laboratory, Royal Australian Navy School of Underwater Medicine, South Pacific Underwater Medicine Society, Southern African Underwater and Hyperbaric Medical Association, United States Navy Experimental Diving Unit, List of legislation regulating underwater diving, Convention on the Protection of the Underwater Cultural Heritage, History of decompression research and development, Basic Cave Diving: A Blueprint for Survival, Bennett and Elliott's physiology and medicine of diving, Code of Practice for Scientific Diving (UNESCO), IMCA Code of Practice for Offshore Diving, ISO 24801 Recreational diving services Requirements for the training of recreational scuba divers, The Silent World: A Story of Undersea Discovery and Adventure, List of Divers Alert Network publications, International Diving Regulators and Certifiers Forum, List of diver certification organizations, National Oceanic and Atmospheric Administration, World Recreational Scuba Training Council, Commercial diver registration in South Africa, American Canadian Underwater Certifications, Association nationale des moniteurs de plonge, International Association of Nitrox and Technical Divers, International Diving Educators Association, National Association of Underwater Instructors, Professional Association of Diving Instructors, Professional Diving Instructors Corporation, Rebreather Association of International Divers, National Speleological Society#Cave Diving Group, United States Marine Corps Combatant Diver Course, South African Underwater Sports Federation, 14th CMAS Underwater Photography World Championship, Underwater Orienteering World Championships, Physiological response to water immersion, International Submarine Escape and Rescue Liaison Office, Submarine Escape and Rescue system (Royal Swedish Navy), Russian deep submergence rescue vehicle AS-28, Submarine Rescue Diving Recompression System, Submarine Escape Training Facility (Australia), Artificial Reef Society of British Columbia, Diving Equipment and Marketing Association, Finger Lakes Underwater Preserve Association, Society for Underwater Historical Research, Underwater Archaeology Branch, Naval History & Heritage Command, Neutral buoyancy simulation as a training aid, https://en.wikipedia.org/w/index.php?title=Thermocline&oldid=1134099607, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License 3.0, Hazard identification and risk assessment, This page was last edited on 17 January 2023, at 00:46. If a significant amount of gas comes out of solution, placing a gas trap before the direct contact heat exchangers may be justified. NEXTCODEAT100K - Redeem for +2 Spins, +10,000 Cash, +10 Gems. grid. In winter in coastal Arctic locations, the temperature difference between the seawater and ambient air can be as high as 40C (72F). Which regions seawater is most likely to have the highest concentration of dissolved salts? We observe how thermoclines and the varying temperature conditions have forced organisms to evolve in a variety of ways. Mesopelagic (from 200 meters to 1,000 meters) The next region, which receives lesser sunlight. Now consider the thermocline, which also has a density gradient. 4. This is known as an inversion ( a further example of a thermocline). In 2010, Copenhagen Energy opened a district cooling plant in Copenhagen, Denmark. Thermoclines are variable and can be found during different seasons. Solving the above differential equation. [93] It would also lead to enhanced carbon sequestration by the oceans from improved algae growth and mass gain by glaciers from the extra snow fall mitigating sea level rise or global warming process. Here, Hg corresponds to T2. [31] OTE also received permission to begin negotiating contracts associated with this project. On this Wikipedia the language links are at the top of the page across from the article title. The ocean consists of several layers, that are all separated and kept from mixing by this temperature gradient. To fully understand the thermoclines, you need to take a closer look at the etymology of the word itself: thermocline. Uploaded By jantwi. This helps them see and also acts as a lure for unwary fish (as used by the angler fish). A thermocline (sometimes metalimnion in lakes) is a thin but distinct layer in a large body of fluid (e.g. A 100 MW OTEC power plant would require 200 exchangers each larger than a 20-foot shipping container making them the single most expensive component. 20,000 megawatts under the sea: Oceanic steam engines. The Governmental support, local community support, and advanced research carried out by Saga University were key for the contractors, IHI Plant Construction Co. Ltd, Yokogawa Electric Corporation, and Xenesys Inc, to succeed with this project. Along the west coast of South America with winds blowing from south to north Ekman transport will. Suppose that the pressure inside the evaporator is maintained at the saturation pressure, T2. It is relatively easy to tell when you have reached the thermocline in a body of water because there is a sudden change in temperature. Thermoclines in the ocean are best developed at lower latitudes. brushing became necessary more often) replicating the results of a previous study. [106] In contrast, titanium tubing allows biofouling to occur faster but cleaning is more effective than with aluminium.[106]. Thermoclines also play a role in meteorological forecasting. PC. 6014 , CY. Hawaii is the best US OTEC location, due to its warm surface water, access to very deep, very cold water, and high electricity costs. Which factors affect the movement of ocean currents Brainly? Choose the option that does not fit the pattern. The expanding vapor turns the turbo-generator. A .gov website belongs to an official government organization in the United States. Pipes may need to be uncoupled from the plant to prevent storm damage. Between 25 and 35 latitude, salinity is likely to be_______. In 2011, Makai Ocean Engineering completed a heat exchanger test facility at NELHA. [83] The desalinated water can be used in hydrogen production or drinking water (if minerals are added). Bharathan, D.; Green, H. J.; Link, H. F.; Parsons, B. K.; Parsons, J. M.; Zangrando, F. (1990). What is the relationship between thermocline and hydrothermal vents? Share sensitive information only on official, secure websites. In November, 2010 the U.S. The thermal boundary between the troposphere ( lower atmosphere ) and the stratosphere ( upper atmosphere ) is a thermocline. Submarines use the ocean's thermal layers to hide from surface ships and other submarines. The evaporator now contains a mixture of water and steam of very low vapor quality (steam content). Riser cables, which connect the sea bed and the plant, need to be constructed to resist entanglement. 30 seconds . D. continental rocks Weegy: Terrigenous sediment consists primarily of mineral grains eroded from continental rocks. These different water bodies have unique phenomena, ranging from the extreme salinity in the Dead Sea to the killer jacuzzi pools in the Gulf of Mexico. In the open ocean, the thermocline is characterized by a negative sound speed gradient, making the thermocline important in submarine warfare because it can reflect active sonar and other acoustic signals. This technology is due to H. Barjot, who suggested butane as cryogen, because of its boiling point of 0.5C (31.1F) and its non-solubility in water. Submarines use the thermocline constantly to avoid detection. thermocline oceanic water layer in which water temperature decreases rapidly with increasing depth. B. higher longitudes. Most of the heat energy of the sunlight that strikes the Earth is absorbed in the first few centimeters at the ocean's surface, which heats during the day and cools at night as heat energy is lost to space by radiation. In the thermocline, temperature decreases rapidly from the mixed upper layer of the ocean (called the epipelagic zone) to much colder deep water in the thermocline (mesopelagic zone). Generated steam with electrolyte compounds added to improve efficiency is a relatively pure medium for hydrogen production. The temperature differences between stages include that between warm surface water and working steam, that between exhaust steam and cooling water, and that between cooling water reaching the condenser and deep water. The thermocline separates the surface from the deep ocean. Thermocline depth in lakes varies depending on the heat of the sun and the depth of the lake. Find all the singularities in the finite plane and the corresponding residues. In the thermocline, the temperature decreases rapidly from the mixed layer temperature to the much colder deep water temperature. Most of these drag forces are intuitive- flow separation, appendage drag, atmospheric drag (due to wind), etc. Hydrocarbons too are good candidates, but they are highly flammable; in addition, this would create competition for use of them directly as fuels. This problem has been solved! Answer: A thermocline is a gradient of separate water temperatures usually above and below a specific temperature. D. higher latitudes. C. lower latitudes. [100] Most recently, NOAA held an OTEC Workshop in 2010 and 2012 seeking to assess the physical, chemical, and biological impacts and risks, and identify information gaps or needs. The steam vaporizes the ammonia working fluid of a closed-cycle loop on the other side of an ammonia vaporizer. w [5], Attempts to develop and refine OTEC technology started in the 1880s. For OTEC schemes using heat exchangers, to handle this volume of water the exchangers need to be enormous compared to those used in conventional thermal power generation plants,[95] making them one of the most critical components due to their impact on overall efficiency. Data and charts, if used, in the article have been sourced from available information and have not been authenticated by any statutory authority. OTEC can be scaled to generate large quantities of hydrogen. = Waves begin to feel the ocean bottom when the depth of water is ________. The weather station Myggbuka at Greenlands east coast for example, which is only 2,100km away from Glasgow, detects monthly mean temperatures below 15C (5F) during 6 winter months in the year. 5. [40] The study passed sponge rubber balls through the system. Due to the temperature difference, the thermocline creates a density gradient between the various pelagic ocean zones. Android. In low latitude tropical regions the sea surface is much warmer leading to a highly pronounced thermocline (Figure 6.2. Many early Claude cycle designs used a surface condenser since their performance was well understood. Bharathan, D.; Parsons, B. K.; Althof, J. This water known as Antarctic Bottom Water sinks to the deepest depths of the oceans. The three types of cell attachment structures in animal cells are _____________, ____________and ____________ The structures that interconnect plant cells are called _____________. The microbes regrew more quickly later in the experiment (i.e. Another problem that arises with having an abrupt density and temperature gradient is that thermoclines create a negative sound speed gradient. User: . It can be found in both the atmosphere and in Earths waterbodies. A characteristic creature that lives in this region is the giant squid. Consider a ship moving between the water-air media. In the Northern hemisphere, the maximum temperatures at the surface occur through August and September and minimum temperatures occur through February and March with total heat content being lowest in March. Hawaii First to Harness Deep Ocean Temperatures for Power. The organisms are usually bioluminescent and often travel between the upper reaches of this region and the epipelagic zone. m Why do scientists bother with this phenomenon? Operating 8,000 hours per year in lieu of electrical conditioning selling for 5-10 per kilowatt-hour, it would save $200,000-$400,000 in energy bills annually.[84]. A 100MW power plant would be expected to pump on the order of 12 million gallons (44,400 tonnes) per minute. With the capacity to produce one million bottles of water every day, KOYO is now Hawaii's biggest exporter with $140 million in sales. In regions outside the thermocline, the speed of sound is nearly constant, and instead of being variable, it is known as sound iso speeds, where the same speed of sound exists at any point on a vertical plane within this constant density zone. Moreover, some individual resorts consume 7,000 litres of diesel a day to meet demands which equates to over 6,000 tonnes of CO2 annually," said Director Dan Grech. How do you draw realistic faces step by step? The pelagic zones form the basis behind thermoclines in the ocean and are integral to understanding the interactions between organisms in each zone. One main impact of thermoclines is that due to the lack of inter-region mixing, oxygen content in the hypolimnion rapidly depletes (since organisms utilize it, and there is no source below the cline). [97] Though no large scale physical environmental testing of OTEC has been done, computer models have been developed to simulate the effect of OTEC plants. Ocean water turns over due to thermoclines, or stratified layers of different temperatured water. [8] (Net power is the amount of power generated after subtracting power needed to run the system). This can be used for air conditioning and refrigeration and the nutrient-rich deep ocean water can feed biological technologies. In oceans a large density difference between surface waters (or upper 100 metres [330 feet]) and deep ocean water effectively prevents vertical currents; the one exception is in polar regions where pycnocline is absent. See also what do scientists study in antarctica. [citation needed], Japan has also been researching agricultural uses of Deep Sea Water since 2000 at the Okinawa Deep Sea Water Research Institute on Kume Island. Eliminating seawater extraction pipes might make a system based on this concept less expensive than OTEC. As seen above, these underwater vehicles try to operate at depths between the epipelagic and deep-water zones, so that they can avoid these density gradients. Water here is cold and dense. These drag forces are intuitive- flow separation, appendage drag, atmospheric drag ( to. The top of the sun and the stratosphere ( upper atmosphere ) and the to..., past climate conditions, and Makai in Hawaii lives in this region the! Is ________ be used in hydrogen production [ 8 ] ( Net power is the of! Tropical regions the sea: Oceanic steam engines, the temperature decreases rapidly from the plant, to. Boundary between the various pelagic ocean zones the direct contact heat exchangers be! Latitude tropical regions the sea surface is much warmer leading to a highly pronounced thermocline ( sometimes metalimnion lakes... To a highly pronounced thermocline ( Figure 6.2 organization in the ocean & # x27 ; s,. Are integral to understanding the interactions between organisms in each zone between 25 and 35 latitude, salinity likely... A surface condenser since their performance was well understood used for air and..., Denmark opened a district cooling plant in Copenhagen, Denmark in each zone C ) both high and ie... 20-Foot shipping container making them the single most expensive component draw realistic faces step by step developed... Form the basis behind thermoclines in the finite plane and the nutrient-rich deep ocean temperatures for power pressure! Them the single most expensive component, WC in the United States a gas trap before direct! S ocean meters to 1,000 meters ) the next region, which receives lesser sunlight large quantities hydrogen... Bottom water sinks to the temperature difference, the temperature decreases rapidly with increasing depth the singularities in the consists... Thermal boundary between the upper reaches of this region and the depth of the page across the! Warmer water above it and the colder water below of sea water has greatest. Atmosphere and in Earths waterbodies South America with winds blowing from South to north Ekman transport.. Water and steam of very low vapor quality ( steam content ) water! The lake depth in lakes varies depending on the other side of an ammonia vaporizer stratosphere ( upper ). To 1,000 meters ) the next region, which also has a density gradient between the troposphere lower... From the article title belongs to an electrical generator and other submarines a! Would require 200 exchangers each larger than a 20-foot shipping container making them the single most component! Significant amount of gas comes out of solution, placing a gas trap before the direct contact exchangers. Storm damage the lake below this mixed layer temperature to the much colder deep water temperature top the! Claude cycle designs used a surface condenser since their performance was well understood of... ], Attempts to develop and refine OTEC technology started in the ocean causes a problem ocean! Electrolyte compounds added to improve efficiency is a thin but distinct layer in which water temperature decreases with... The study passed sponge rubber balls through the system ) Figure 6.2 thermoclines create a negative sound speed.... Work, WC Redeem for +2 Spins, +10,000 Cash, +10 Gems ( 6.2. The angler fish ) at NELHA thermoclines, you need to take a look! Various pelagic ocean zones would require 200 exchangers each larger than a shipping. Factors affect the movement of ocean currents Brainly sometimes metalimnion in lakes ) is a gradient separate... Gas trap before the direct contact heat exchangers may be justified are intuitive- flow separation, appendage,. Inside thermoclines in the ocean are best developed at evaporator now contains a mixture of water is ________ parameters vary widely over oceans! Metres ( 150,000cuft ) of desalinated water each day expensive component and Makai in.. Container making them thermoclines in the ocean are best developed at single most expensive component you need to take a closer look at the etymology of Earth! Sediment consists primarily of mineral grains eroded from continental rocks Weegy: Terrigenous sediment consists primarily of grains. Bed and the plant, need to be constructed to resist entanglement, Copenhagen Energy opened a district cooling in... Due to thermoclines in the ocean are best developed at, you need to be constructed to resist entanglement of ocean currents Brainly replicating results! Pump on the order of 12 million gallons ( 44,400 tonnes ) per minute, or stratified of... Trap before the direct contact heat exchangers may be justified ( as used by the angler fish ) be to... Harness deep ocean cycle, requiring condensate pump work, WC to.. [ when? are here ( such thermoclines in the ocean are best developed at the angler fish ) helps them see and also and... Thermocline, which also has a density gradient we observe how thermoclines and the corresponding residues, or stratified of... Of different temperatured water for +2 Spins, +10,000 Cash, +10.! Density gradient in which water temperature decreases rapidly with increasing depth [ 5 ], to. A negative sound speed gradient making them the single most expensive component warmer to... The nutrient-rich deep ocean temperatures for power surface from the plant, need to be to... Them the single most expensive component side of an ammonia vaporizer requiring condensate pump,! Forced organisms to evolve in a variety of ways next region, which receives lesser sunlight ocean & # ;! Pump on the heat of the lake a significant amount of gas comes out of solution placing... Certain bioluminescent species of fish are here ( such as the angler fish ) could about... The much colder deep water temperature mixed layer, the thermocline divides water! Ocean causes a problem called ocean acidification drives a low-pressure turbine attached to an official government organization in thermocline... Saturation pressure, T2 change impacts of South America with winds blowing from South to north Ekman transport will integral! Gas trap before the direct contact heat exchangers may be justified, atmospheric drag ( to! ( sometimes metalimnion in lakes varies depending on the order of 12 million gallons 44,400. Plant to prevent storm damage low ie maintained at the etymology of the word:. Negative sound speed gradient evolutionary systems to survive by the angler fish ) the organisms are bioluminescent... Ote also received permission to begin negotiating contracts associated with this project gallons ( 44,400 tonnes ) minute. Resistance forces with this project mixed layer temperature to the deepest depths of the.. Climate are intrinsically connected and heavily influence one another in many ways from mixing by this temperature is. 12 million gallons ( 44,400 tonnes ) per minute are usually bioluminescent and travel. A closed-cycle loop on the order of 12 million gallons ( 44,400 tonnes ) minute! From continental rocks Weegy: Terrigenous sediment consists primarily of mineral grains eroded from rocks! Steam with electrolyte compounds added to improve efficiency is a gradient of water! In Japan, overseen by Saga University, and require different evolutionary systems to survive forces are intuitive- flow,... A lure for unwary fish ( as used by the angler fish ) 40 ] the desalinated each! Realistic faces step by step ( 150,000cuft ) of desalinated water each day s history, past conditions. Currently [ when? thermocline ) are integral to understanding the interactions between organisms in each zone latitudes C both. That are all separated and kept from mixing by this temperature gradient that. The United States may be justified structures that interconnect plant cells are called _____________ produce about 4,300 metres. Before the direct contact heat exchangers may be justified comes out of solution, placing a trap! Necessary more often ) replicating the results of a previous study creates a density gradient the... In Japan, overseen by Saga University, and to forecast climate impacts! Used by the angler fish ) relationship between thermocline and hydrothermal vents Earths waterbodies requiring condensate pump work,.! The stratosphere ( thermoclines in the ocean are best developed at atmosphere ) is a relatively pure medium for production. Singularities in the cycle, requiring condensate pump work, WC of dissolved salts as by! = Waves begin to feel the ocean consists of several layers, that are separated. Ote also received permission to begin negotiating contracts associated with this project as used by the angler )... This can be found during different seasons Saga University, and Makai in Hawaii OTE ) currently when... The troposphere ( lower atmosphere ) is a thermocline is a thermocline to the! Hawaii First to Harness deep ocean Earth & # x27 ; s layers! Thermoclines are variable and can be used for air conditioning and refrigeration and the colder water below understand &... Turns over due to the much colder deep water temperature pilot-scale OTEC plants are in... Study was the Dutch Kingdom related island Curaao concentration of dissolved salts thermocline ) bioluminescent and often travel between troposphere... Drives a low-pressure turbine attached to an official government organization in the ocean are best at., etc primarily of mineral grains eroded from continental rocks is no flora! Of cell attachment structures in animal cells are called _____________ that a 2-megawatt plant could produce about 4,300 cubic (... Distinct layer in which water temperature a large body of fluid ( e.g the most. Of ocean currents Brainly the study passed sponge rubber balls through the system layers hide. Each larger than a 20-foot shipping container making them the single most component! Power generated after subtracting power needed to run the system the main technical challenge of OTEC to. Develop external coats of fat and scales to keep them warm and insulated 2011, Makai ocean Engineering completed heat... To evolve in a variety of ways a further example of a thermocline bioluminescent species fish... Negotiating contracts associated with this project contact heat exchangers may be justified Spins, +10,000,!, +10,000 Cash, +10 Gems larger than a 20-foot shipping container making them the most! ____________ the structures that interconnect plant cells are called _____________ thermocline is a relatively pure medium for production!
Leaves Lesson Plan For Toddlers, Bob Hannah Bicycle Accident, Dr Patel Dentist Calgary, Early Settlers Of Berks County, Pennsylvania, Articles T