Misplaced Pages

#25974

95-652: The Pokagon are descendants of the residents of allied Potawatomi villages that were historically located along the St. Joseph , Paw Paw and Kalamazoo rivers in what are now southwest Michigan and northern Indiana. They were the only Potawatomi band to gain permission from the United States government to remain in Michigan after Indian removal in the 1830s. The tribe has been federally recognized since 1994 legislation affirmed its status; it has established self-government. Some believe

190-461: A BGA heat sink directly to the component. The clips make use of the gap created by the ball grid array (BGA) between the component underside and PCB top surface. The clips therefore require no holes in the PCB. They also allow for easy rework of components. For larger heat sinks and higher preloads, push pins with compression springs are very effective. The push pins, typically made of brass or plastic, have

285-555: A community center. In a competition for federal stimulus funds, the Pokagon were granted $ 2 million from the Department of Housing and Urban Development to build a planned community center at their tribal center in Dowagiac. The 8,500-square-foot (790 m) building has been designed to satisfy Silver LEED standards, and incorporates a number of innovations to reduce its energy use and create

380-457: A fan, but in all instances, eventually to the environment. Two additional design factors also influence the thermal/mechanical performance of the thermal design: As power dissipation of components increases and component package size decreases, thermal engineers must innovate to ensure components won't overheat . Devices that run cooler last longer. A heat sink design must fulfill both its thermal as well as its mechanical requirements. Concerning

475-411: A flexible barb at the end that engages with a hole in the PCB; once installed, the barb retains the pin. The compression spring holds the assembly together and maintains contact between the heat sink and component. Care is needed in selection of push pin size. Too great an insertion force can result in the die cracking and consequent component failure. For very large heat sinks, there is no substitute for

570-439: A heat sink, this means that heat does not distribute uniformly through the heat-sink base. The spreading resistance phenomenon is shown by how the heat travels from the heat source location and causes a large temperature gradient between the heat source and the edges of the heat sink. This means that some fins are at a lower temperature than if the heat source were uniform across the base of the heat sink. This nonuniformity increases

665-407: A rectangular copper body. Fin efficiency is one of the parameters that makes a higher-thermal-conductivity material important. A fin of a heat sink may be considered to be a flat plate with heat flowing in one end and being dissipated into the surrounding fluid as it travels to the other. As heat flows through the fin, the combination of the thermal resistance of the heat sink impeding the flow and

760-454: A satellite in space, a 100 °C (373 K) surface facing the Sun will absorb a lot of radiant heat, because the Sun 's surface temperature is nearly 6000 K, whereas the same surface facing deep space will radiate a lot of heat, since deep space has an effective temperature of only several Kelvin. Heat dissipation is an unavoidable by-product of electronic devices and circuits. In general,

855-716: A sustainable building: including a green roof , thick concrete flooring to act as a heat sink , windows to the south to gain winter sun and heat, and geothermal systems. In 2018 the Field Museum in Chicago, which stands on Pokagon land, included a tribal member in its advisory committee of scholars and museum professionals. The committee is tasked with informing the transformation of the Native North American Hall to incorporate perspectives and voices of Native peoples and Indigenous nations. A decreasing number of elders among

950-448: A thermal resistance (heat sink to ambient air) ranging from 0.4 °C/W for a large sink meant for TO-3 devices, up to as high as 85 °C/W for a clip-on heat sink for a TO-92 small plastic case. The popular 2N3055 power transistor in a TO-3 case has an internal thermal resistance from junction to case of 1.52 °C/W . The contact between the device case and heat sink may have a thermal resistance between 0.5 and 1.7 °C/W , depending on

1045-421: A variety of heat-generating bodies to a heat sink. Placing a conductive thick plate as a heat-transfer interface between a heat source and a cold flowing fluid (or any other heat sink) may improve the cooling performance. In such arrangement, the heat source is cooled under the thick plate instead of being cooled in direct contact with the cooling fluid. It is shown that the thick plate can significantly improve

SECTION 10

#1732851081026

1140-418: A vital habitat for resident species as well, such as wild turkey ( Meleagris gallopavo ), coyote ( Canis latrans ), fox, beaver ( Castor canadensis ), mink ( Neogale vison ), Indiana bat ( Myotis sodalis ), eastern box turtle ( Terrapene carolina carolina ), and the rare spotted turtle ( Clemmys guttata ) and northern redbelly snake ( Storeria occipitomaculata occipitomaculata ), both protected by

1235-548: A wall of water, 3 to 5 feet (0.91 to 1.52 m) high, up the river at St. Joseph and Benton Harbor. This raised the level of the river by 4 to 5 feet (1.2 to 1.5 m). The cause of the seiche was unknown, but has been attributed to a sudden squall or change in atmospheric pressure. Factories located in South Bend because of access to the river and hydro-power created in the East and West Races. The water rights to what would become

1330-634: A wide meandering route generally northwest through Niles and past Berrien Springs . Just North of Niles it receives the Dowagiac River . It divides St. Joseph and Benton Harbor , receiving the Paw Paw River from the north approximately 1 mile (1.6 km) from its mouth in St. Joseph on Lake Michigan. There are 190 dams in the St. Joseph River watershed, and 17 on the river mainstem. Most of these dams block fish passage, although fish ladders constructed on

1425-563: Is a full-service police department, servicing all areas within the Tribe's jurisdiction. The Tribal Police are charged with enforcing federal, state, and local laws, including the Pokagon Band Code of Offenses. The Pokagon Band Gaming Commission was established the in 2007 as an independent subdivision. The Gaming Commission regulates all gaming conducted within Pokagon Band jurisdiction under

1520-523: Is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature. In computers, heat sinks are used to cool CPUs , GPUs , and some chipsets and RAM modules. Heat sinks are used with other high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light-emitting diodes (LEDs), where

1615-866: Is building a hydroelectric dam on the waterway. The project was funded by the University of Notre Dame . Two sites in the river basin, Moccasin Bluff and Fort St. Joseph , are listed on the U.S. National Register of Historic Places . Carey Mission , Fort Miami , and Burnett Trading Post are listed as State Registered Historic Sites . Before European settlement, the watershed was dominated by deciduous forests consisting of maple, ash, oak, elm, walnut, and beech species, along with pockets of white, red and jack pine species. There were also prairies up to several miles across, which were grazed by elk ( Cervus canadensis ), white-tailed deer ( Odocoileus virginianus ), moose ( Alces alces ), and bison ( Bison bison ). By 1900

1710-445: Is for rough surfaces, the major contribution to the resistance is made by the gaps. To decrease the thermal contact resistance, the surface roughness can be decreased while the interface pressure is increased. However, these improving methods are not always practical or possible for electronic equipment. Thermal interface materials (TIM) are a common way to overcome these limitations. Properly applied thermal interface materials displace

1805-517: Is frequently air, but can also be water, refrigerants or oil. If the fluid medium is water, the heat sink is frequently called a cold plate. In thermodynamics a heat sink is a heat reservoir that can absorb an arbitrary amount of heat without significantly changing temperature. Practical heat sinks for electronic devices must have a temperature higher than the surroundings to transfer heat by convection, radiation, and conduction. The power supplies of electronics are not absolutely efficient, so extra heat

1900-426: Is increased by decreasing the fin aspect ratio (making them thicker or shorter), or by using a more conductive material (copper instead of aluminium, for example). Another parameter that concerns the thermal conductivity of the heat-sink material is spreading resistance. Spreading resistance occurs when thermal energy is transferred from a small area to a larger area in a substance with finite thermal conductivity. In

1995-453: Is low, such as a flat non-finned panel with low airflow, radiative cooling can be a significant factor. Here the surface properties may be an important design factor. Matte-black surfaces radiate much more efficiently than shiny bare metal. A shiny metal surface has low emissivity. The emissivity of a material is tremendously frequency-dependent and is related to absorptivity (of which shiny metal surfaces have very little). For most materials,

SECTION 20

#1732851081026

2090-536: Is mechanically soft. Aluminium alloys 6060 (low-stress), 6061 , and 6063 are commonly used, with thermal conductivity values of 166 and 201 W/(m·K) respectively. The values depend on the temper of the alloy. One-piece aluminium heat sinks can be made by extrusion , casting , skiving or milling . Copper has excellent heat-sink properties in terms of its thermal conductivity, corrosion resistance, biofouling resistance, and antimicrobial resistance (see also Copper in heat exchangers ). Copper has around twice

2185-535: Is more expensive than tape, but provides a greater mechanical bond between the heat sink and component, as well as improved thermal conductivity. The epoxy chosen must be formulated for this purpose. Most epoxies are two-part liquid formulations that must be thoroughly mixed before being applied to the heat sink, and before the heat sink is placed on the component. The epoxy is then cured for a specified time, which can vary from 2 hours to 48 hours. Faster cure time can be achieved at higher temperatures. The surfaces to which

2280-430: Is one of the most cost-effective heat sink attachment materials. It is suitable for low-mass heat sinks and for components with low power dissipation. It consists of a thermally conductive carrier material with a pressure-sensitive adhesive on each side. This tape is applied to the base of the heat sink, which is then attached to the component. Following are factors that influence the performance of thermal tape: Epoxy

2375-437: Is produced that may be detrimental to the function of the device. As such, a heat sink is included in the design to disperse heat. Fourier's law of heat conduction shows that when there is a temperature gradient in a body, heat will be transferred from the higher-temperature region to the lower-temperature region. The rate at which heat is transferred by conduction, q k {\displaystyle q_{k}} ,

2470-459: Is proportional to the product of the temperature gradient and the cross-sectional area through which heat is transferred. When it is simplified to a one-dimensional form in the x direction, it can be expressed as: For a heat sink in a duct, where air flows through the duct, the heat-sink base will usually be hotter than the air flowing through the duct. Applying the conservation of energy, for steady-state conditions, and Newton's law of cooling to

2565-526: Is still very much in use. In general, a heat sink performance is a function of material thermal conductivity, dimensions, fin type, heat transfer coefficient , air flow rate, and duct size. To determine the thermal performance of a heat sink, a theoretical model can be made. Alternatively, the thermal performance can be measured experimentally. Due to the complex nature of the highly 3D flow in present applications, numerical methods or computational fluid dynamics (CFD) can also be used. This section will discuss

2660-548: Is the flared fin heat sink, where the fins are not parallel to one another. Flaring the fins decreases flow resistance and makes more air go through the heat-sink fin channel; otherwise, more air would bypass the fins. Slanting them keeps the overall dimensions the same, but offers longer fins. Examples of the three types are shown in the image on the right. Forghan, et al. have published data on tests conducted on pin fin, straight fin, and flared fin heat sinks. They found that for low air approach velocity, typically around 1 m/s,

2755-409: Is the need for holes in the PCB. Thermal contact resistance occurs due to the voids created by surface roughness effects, defects and misalignment of the interface. The voids present in the interface are filled with air. Heat transfer is therefore due to conduction across the actual contact area and to conduction (or natural convection) and radiation across the gaps. If the contact area is small, as it

2850-794: Is the third largest watershed draining to Lake Michigan. The land within its bounds is primarily used for agriculture . The river and its tributaries provide a variety of paddling and fishing environments. Historically, the river served as an important canoe transportation route for various Native American tribes, and for French Canadian Voyageurs . The St. Joseph River watershed drains 4,685 square miles (12,130 km ) from 15 counties: Berrien , Branch , Calhoun , Cass , Hillsdale , Kalamazoo , St. Joseph and Van Buren in Michigan and DeKalb , Elkhart , Kosciusko , LaGrange , Noble , St. Joseph and Steuben in Indiana. The watershed includes 3,742 river miles (6,022 km) and flows through and near

2945-418: Is to pack as much surface area into a given volume as possible, while working in any orientation of fluid flow. Kordyban has compared the performance of a pin-fin and a straight-fin heat sink of similar dimensions. Although the pin-fin has 194 cm surface area while the straight-fin has 58 cm , the temperature difference between the heat-sink base and the ambient air for the pin fin is 50 °C , but for

Pokagon Band of Potawatomi Indians - Misplaced Pages Continue

3040-521: The Illinois Country . European American settlement of the St. Joseph river basin area began to increase in earnest after southwestern Michigan was surveyed in 1829. From the early 1830s until 1846, the river bore various commodities from upstream to a busy port at St. Joseph, where they were loaded onto lake boats for shipment to Chicago and elsewhere. On April 11, 1893, a Lake Michigan seiche (a phenomenon similar to an ocean tsunami ) pushed

3135-643: The Ojibwe and Odawa Anishinaabe peoples, they migrated west to the Great Lakes region some 500–800 years ago in a "Great Migration." The Pokagon Band of Potawatomi Indians were party to 11 treaties with the federal government, with the major land cession being under the 1833 Treaty of Chicago . During the Indian removals , many Potawatomi bands were moved west, but Chief Leopold Pokagon negotiated to keep his Potawatomi band of 280 people in southwestern Michigan. They were

3230-775: The Old Sauk Trail , a major east-west Indian trail, crossed the river. The indigenous trade and navigation networks in the area allowed for extensive trade and movement of people, which allowed early Europeans access to the area in 1675 when Père Jacques Marquette was guided up the Mississippi River via the Illinois River , then to the Kankakee River and portaged to Sakiwasipi and then down to Lake Michigan. On November 1, 1679 René Robert Cavelier, Sieur de La Salle sailed southeast across Lake Michigan and built Fort Miami at

3325-549: The Potawatomi Chief Baw Beese . The river follows a zigzag route generally westward across southern Michigan, dipping into northern Indiana. From its headwaters, it flows initially northwest past Hillsdale into southeastern Calhoun County , then turns abruptly southwest to flow past Tekonsha , Union City , Sherwood , and Mendon . At Three Rivers it is joined from the north by the Rocky and Portage rivers, and by

3420-511: The Potawatomi and early settlers used spears, seines and dip nets to catch their annual supply of fish. The abundance of lake sturgeon made the area around Niles famous in the mid-to late-1800s. Fish up to 12 feet (3.7 m) long and 300 pounds (140 kg) were taken by anglers, and their roe was exported to Russia as caviar. Sturgeon used to migrate as far as Hillsdale County, Michigan , and Sturgeon Lake near Colon, Michigan , still bears

3515-722: The Prairie River from the east, after making an abrupt turn south. At Constantine it receives the Fawn River from the east. Next, after returning to a southwest course, it receives the Pigeon River from the east, near the Michigan– Indiana state line. In northern Indiana, the river flows west-southwest through Elkhart , Mishawaka , and South Bend , where it turns abruptly to north to re-enter southwestern Michigan in southeastern Berrien County . In southwestern Michigan, it follows

3610-442: The die temperature of the integrated circuit. Thermal adhesive or thermal paste improve the heat sink's performance by filling air gaps between the heat sink and the heat spreader on the device. A heat sink is usually made out of a material with a high thermal conductivity , such as aluminium or copper. A heat sink transfers thermal energy from a higher-temperature device to a lower-temperature fluid medium. The fluid medium

3705-590: The salmonid runs were extended to the Twin Branch Dam in Indiana, a distance of 63 miles (101 km) from Lake Michigan. This enabled the trout and salmon to spawn in coldwater tributaries such as McCoy Creek . Although completion of fish ladders on the lowest five mainstem dams in 1992 allowed salmonine passage as far as Twin Branch Dam in Mishawaka, Indiana , 94% of the fish that pass are salmon and trout, as

3800-582: The salmonids to run an additional 10 miles (16 km) upstream to the Buchanan Dam. In 1980 the Michigan Department of Natural Resources, Indiana Department of Natural Resources and United States Fish and Wildlife Service signed the "St. Joseph River Interstate Cooperative Salmonid Management Plan", which led to construction of fish ladders at the Buchanan, Niles, South Bend and Mishawaka dams. By 1992

3895-586: The East and West Races were claimed by Alexis Coquillard and Lathrop Taylor in 1831, when the city of South Bend was founded. Although the idea of digging a mill race (man-made canal) was put forth in 1835, a dam and the East and West Races were not constructed until 1843. The construction was done by the South Bend Manufacturing Company, incorporated in December 1842 for this very purpose. The South Bend Manufacturing Company thus became owner of

Pokagon Band of Potawatomi Indians - Misplaced Pages Continue

3990-709: The Gaming Regulatory Act, the federal Indian Gaming Regulatory Act , and the tribal-state Gaming Compact between the Band and the State of Michigan and Indiana . St. Joseph River (Lake Michigan) The St. Joseph River (known locally as the St. Joe ) is a 210-mile-long (340 km) river that flows in a generally westerly direction through southern Michigan and northern Indiana , United States , before emptying into Lake Michigan . The St. Joseph River drainage basin covers 4,685 square miles (12,130 km ), and

4085-540: The Kalamazoo-Portage, Elkhart-Goshen, Mishawaka-South Bend, and St. Joseph/Benton Harbor metropolitan areas. The St. Joseph River main stem is 206 miles (332 km) long, rising in southern Michigan in Hillsdale County flowing from Baw Beese Lake , within 5 miles (8 km) of the headwaters of the other St. Joseph River of the eastward-flowing Maumee River watershed. Baw Beese Lake was historically named for

4180-600: The Oliver Chilled Plow Works constructed a hydro-electric power plant on the waterway to supply electricity for light, heat, and power to the Oliver Opera House, Oliver Hotel, South Bend factories, and other Oliver buildings. Other sources of energy and changes in technology resulted in the canals no longer being used for industrial purposes. In the late 1940s the Indiana and Michigan Electric Company purchased

4275-714: The Pokagon Band government. The Tribal Court Judiciary consists of the Chief Judge, one Associate Judge, and three Appellate Court Justices. All members of the Judiciary are appointed by the Tribal Council to serve staggered four (4)-year terms. The Pokagon Tribal Police Department was established in 2003 to provide direct law enforcement services to the tribal members and visitors in the ten-county tribal geographic boundaries in Michigan and Indiana . The Pokagon Tribal Police Department

4370-547: The Potawatomi bands speak the language, but the Pokagon are participating in a program to restore teaching and use of the language: See Potawatomi language § Language revitalization . Members of the tribal council, including the chairman, are elected by members of the tribe. By their positions, they also serve as members of the Pokagon Gaming Authority. The Tribal Judiciary is a separate and independent branch of

4465-535: The Potawatomi originated as a people along the Atlantic coastline at the mouth of the St. Lawrence River. Archaeologists say they migrated south from Ontario about 1,000 years ago. Other tribal elders, including Michael Williams, told that Potawatomi originated at the mouth of the Grand River at its mouth at Lake Michigan or along the St. Joseph River near Mishawaka, Indiana. Some followers believe over centuries, along with

4560-431: The aforementioned methods for the determination of the heat sink thermal performance. One of the methods to determine the performance of a heat sink is to use heat transfer and fluid dynamics theory. One such method has been published by Jeggels, et al., though this work is limited to ducted flow. Ducted flow is where the air is forced to flow through a channel which fits tightly over the heat sink. This makes sure that all

4655-399: The air goes through the channels formed by the fins of the heat sink. When the air flow is not ducted, a certain percentage of air flow will bypass the heat sink. Flow bypass was found to increase with increasing fin density and clearance, while remaining relatively insensitive to inlet duct velocity. The heat sink thermal resistance model consists of two resistances, namely the resistance in

4750-412: The air that is present in the gaps between the two objects with a material that has a much-higher thermal conductivity. Air has a thermal conductivity of 0.022 W/(m·K) while TIMs have conductivities of 0.3 W/(m·K) and higher. When selecting a TIM, care must be taken with the values supplied by the manufacturer. Most manufacturers give a value for the thermal conductivity of a material. However,

4845-554: The air, and radiation . Heat transfer by radiation is a function of both the heat-sink temperature and the temperature of the surroundings that the heat sink is optically coupled with. When both of these temperatures are on the order of 0 °C to 100 °C, the contribution of radiation compared to convection is generally small, and this factor is often neglected. In this case, finned heat sinks operating in either natural-convection or forced-flow will not be affected significantly by surface emissivity . In situations where convection

SECTION 50

#1732851081026

4940-496: The case size and use of grease or insulating mica washer. The materials for heat sink applications should have high heat capacity and thermal conductivity in order to absorb more heat energy without shifting towards a very high temperature and transmit it to the environment for efficient cooling. The most common heat sink materials are aluminium alloys . Aluminium alloy 1050 has one of the higher thermal conductivity values at 229 W/(m·K) and heat capacity of 922 J/(kg·K), but

5035-583: The casino were on the Las Vegas Strip , it would be the second largest there. Architecturally the casino's rotunda is built in the style of the Potawatomi people's traditional lodges. A second, satellite casino, Four Winds Hartford , opened in 2011 in Hartford, Michigan . The tribe opened a third, Four Winds Dowagiac , in 2013 in Dowagiac, Michigan . The band has been limited to three casinos by its 2008 compact with

5130-744: The cities and streets in the Michigan area have adopted Potawatomi names. As a federally recognized tribe, the Pokagon Band were able to develop and open in 2007 the Four Winds New Buffalo casino on the Pokagon Reservation. It is located in New Buffalo Township , near New Buffalo, Michigan . The casino is operated in accordance with the Indian Gaming Regulatory Act and a compact with Michigan. It expanded in 2011 due to its success. The Chicago Tribune reported that if

5225-678: The die over the ambient air can be calculated. The idea of thermal resistance of a semiconductor heat sink is an approximation. It does not take into account non-uniform distribution of heat over a device or heat sink. It only models a system in thermal equilibrium and does not take into account the change in temperatures with time. Nor does it reflect the non-linearity of radiation and convection with respect to temperature rise. However, manufacturers tabulate typical values of thermal resistance for heat sinks and semiconductor devices, which allows selection of commercially manufactured heat sinks to be simplified. Commercial extruded aluminium heat sinks have

5320-685: The early 1980s, the East Race canal was re-excavated. It was converted to a man-made whitewater kayaking course, now known as the East Race Waterway. 41°40′34″N 86°14′42″W  /  41.676°N 86.245°W  / 41.676; -86.245 In 1984, the abandoned East Race canal in South Bend, whose outlets were both at the river, was converted into the East Race Waterway , North America's first artificial whitewater waterway and

5415-414: The efficiency of the heat sink will decline. For semiconductor devices used in a variety of consumer and industrial electronics, the idea of thermal resistance simplifies the selection of heat sinks. The heat flow between the semiconductor die and ambient air is modeled as a series of resistances to heat flow; there is a resistance from the die to the device case, from the case to the heat sink, and from

5510-407: The emissivity in the visible spectrum is similar to the emissivity in the infrared spectrum; however, there are exceptions – notably, certain metal oxides that are used as " selective surfaces ". In vacuum or outer space , there is no convective heat transfer, thus in these environments, radiation is the only factor governing heat flow between the heat sink and the environment. For

5605-437: The entire length of the main stem, if they are prepared to portage. Many of the larger tributaries offer opportunities for paddling, hiking, hunting, and fishing. A list of dams on the St. Joseph River. AKA Niles Dam Jack Mosley AKA Fairbanks Morse Dam St. Joseph River crossings are located in towns or cities within seven counties of two states . Heat sink A heat sink (also commonly spelled heatsink, )

5700-408: The epoxy is applied must be clean and free of any residue. The epoxy bond between the heat sink and component is semi-permanent/permanent. This makes re-work very difficult and at times impossible. The most typical damage caused by rework is the separation of the component die heat spreader from its package. More expensive than tape and epoxy, wire form z-clips attach heat sinks mechanically. To use

5795-511: The first of four in the United States. Locals first proposed in 1973 that the 19th-century waterway be reopened; construction began in August 1982 and the East Race reopened on June 29, 1984. Through the use of movable barriers and obstacles, the East Race can be configured to provide a whitewater course for recreational and competitive canoeing, kayaking and rafting. In 2021, the East Race was temporarily closed for construction. The City of South Bend

SECTION 60

#1732851081026

5890-533: The headwaters in southwestern Michigan, where travelers could make a portage to the St. Joseph River of the Maumee River watershed, which drained into Lake Erie . The second major transfer point was at South Bend, Indiana, where a short portage to the nearby Kankakee River allowed access to the Illinois River and subsequently to the Mississippi. Another major access point along river was at Niles, Michigan, where

5985-423: The heat dissipation ability of the component itself is insufficient to moderate its temperature. A heat sink is designed to maximize its surface area in contact with the cooling medium surrounding it, such as the air. Air velocity, choice of material, protrusion design and surface treatment are factors that affect the performance of a heat sink. Heat sink attachment methods and thermal interface materials also affect

6080-425: The heat lost due to convection, the temperature of the fin and, therefore, the heat transfer to the fluid, will decrease from the base to the end of the fin. Fin efficiency is defined as the actual heat transferred by the fin, divided by the heat transfer were the fin to be isothermal (hypothetically the fin having infinite thermal conductivity). These equations are applicable for straight fins: where Fin efficiency

6175-404: The heat sink base, R b {\displaystyle R_{b}} , and the resistance in the fins, R f {\displaystyle R_{f}} . The heat sink base thermal resistance, R b {\displaystyle R_{b}} , can be written as follows if the source is a uniformly applied the heat sink base. If it is not, then the base resistance

6270-411: The heat sink to the ambient air. The sum of these resistances is the total thermal resistance from the die to the ambient air. Thermal resistance is defined as temperature rise per unit of power, analogous to electrical resistance, and is expressed in units of degrees Celsius per watt (°C/W). If the device dissipation in watts is known, and the total thermal resistance is calculated, the temperature rise of

6365-400: The heat sink's effective thermal resistance. To decrease the spreading resistance in the base of a heat sink: A pin fin heat sink is a heat sink that has pins that extend from its base. The pins can be cylindrical, elliptical, or square. A second type of heat sink fin arrangement is the straight fin. A variation on the straight fin heat sink is a cross-cut heat sink. A third type of heat sink

6460-404: The heat transfer between the heat source and the cooling fluid by conducting the heat current in an optimal manner. The two most attractive advantages of this method are that no additional pumping power and no extra heat-transfer surface area, that is quite different from fins (extended surfaces). The heat transfer from the heat sink occurs by convection of the surrounding air, conduction through

6555-425: The interface between the two materials. The selection does not include the cost of the material. Electrical resistivity may be important depending upon electrical design details. Light-emitting diode (LED) performance and lifetime are strong functions of their temperature. Effective cooling is therefore essential. A case study of a LED based downlighter shows an example of the calculations done in order to calculate

6650-496: The ladders were not designed to permit passage of migrating native fish. Historically, the migrating native species included lake sturgeon ( Acipenser fulvescens ), bass (smallmouth and largemouth), redhorse (silver, golden, shorthead, river, and greater) ( Moxostoma ssp. ), walleye ( Sander vitreus ), lake trout ( Salvelinus namaycush ), lake whitefish ( Coregonus clupeaformis ), northern pike ( Esox lucius ) and American pickerel ( E. americanus vermiculatus ). Every spring

6745-443: The latter, the component must remain in thermal contact with its heat sink with reasonable shock and vibration. The heat sink could be the copper foil of a circuit board, or a separate heat sink mounted onto the component or circuit board. Attachment methods include thermally conductive tape or epoxy, wire-form z clips , flat spring clips, standoff spacers, and push pins with ends that expand after installing. Thermally conductive tape

6840-401: The lower dams allow salmonine passage as far as the Twin Branch Dam in Mishawaka, Indiana . But, the fish ladders are not adequate for many native species, such as sturgeon , and the dams tend to be built on the higher gradient portions of the river, which are the most critical river habitats for fish spawning. saakiiweesiipiiwi (Outlet River, also historically spelt Sakiwasipi ), as it

6935-576: The mouth of the river. La Salle named the river La Rivière des Miamis (River of the Miamis). At the end of 1679, La Salle followed indigenous trade routes in the opposite direction of that taken by Marquette; heading up the St. Joseph River and portaging to the Kankakee River, getting as far west on the Illinois River as modern-day Peoria, Illinois , before returning to Fort Miami. After giving up on

7030-527: The name of this mighty fish. Now the spawning sturgeon rarely reach Niles, as they are impeded by the dam at Berrien Springs , reducing the length of the river used by them for spawning by 155 miles (249 km). Historically, ninety-seven species of fish were native to the St. Joseph River Basin. In 1994, the Friends of the St. Joe River (FotSJR), a non-profit conservation organization, was founded by Athens, Michigan , residents Al and Margaret Smith, to organize

7125-633: The only Potawatomi band who did not remove west of the Mississippi River. Under the Indian Reorganization Act of 1934, the Pokagon Band wanted to restore self-government and requested recognition as a tribe by the Department of the Interior , but were denied because of conditions of their treaties and the legislation. After years of petitioning, the Pokagon Band regained recognition in 1994 through legislation affirming their status. Many of

7220-415: The other side of the clip can be placed in the other anchor. The deflection develops a spring load on the component, which maintains very good contact. In addition to the mechanical attachment that the z-clip provides, it also permits using higher-performance thermal interface materials, such as phase change types. Available for processors and ball grid array (BGA) components, clips allow the attachment of

7315-517: The plan was developed, the river carried the greatest portion of atrazine into Lake Michigan. It is an agricultural herbicide associated with cancer even at low levels and is a very common contaminant of drinking water. The St. Joseph River is a trout and salmon sport fishery, encompassing 47 miles (76 km) of river in Michigan and 16 miles (26 km) in Indiana. The economic benefits to local Michigan and Indiana communities are estimated at several million dollars annually. Canoeists can travel

7410-524: The required heat sink necessary for the effective cooling of lighting system. The article also shows that in order to get confidence in the results, multiple independent solutions are required that give similar results. Specifically, results of the experimental, numerical and theoretical methods should all be within 10% of each other to give high confidence in the results. Temporary heat sinks are sometimes used while soldering circuit boards, preventing excessive heat from damaging sensitive nearby electronics. In

7505-589: The return of his ship, Le Griffon , in April 1680, he became the first European to walk the well traveled indigenous routes east across the Lower Peninsula of Michigan back to the Detroit River and Canada. The French established Fort St. Joseph at the crossroads of Old Sauk Trail and this well-established east–west trail in 1691. The watershed was later used as canoe route by early French fur trappers in

7600-489: The rights along the East Race canal. They began filling it in around 1954 for re-use for other purposes. In 1973 the Oliver Chilled Plow Works hydro-electric plant was demolished to make room for construction of the Century Center , which was completed in 1977. The West Race still exists as a canal North of Jefferson Boulevard and South of Colfax Avenue on the banks of Century Center, between Pier Park and Island Park. In

7695-470: The river communities to clean and restore the river. In 2002 FotSJR developed the St. Joseph River Watershed Management Plan, with grant support from the Michigan Department of Environmental Quality . The river delivers significant pollutants to Lake Michigan - including sewage overflows from riverside communities, sediments and toxic substances such as mercury and polychlorinated biphenyl (PCB). When

7790-417: The simplest case, this means partially gripping a component using a heavy metal crocodile clip, hemostat , or similar clamp. Modern semiconductor devices, which are designed to be assembled by reflow soldering, can usually tolerate soldering temperatures without damage. On the other hand, electrical components such as magnetic reed switches can malfunction if exposed to hotter soldering irons, so this practice

7885-501: The state of Michigan. In 2018 the tribe opened Four Winds South Bend in South Bend, Indiana , which it has claimed qualifies for gaming pursuant to specific provisions of the Indian Gaming Regulatory Act . In February 2021, the Pokagon Band of Potawatomi Indians announced the rollout of its online gaming platform, making it the 11th licensee to offer both online sports betting and casino gaming in Michigan. The tribe has invested revenues from gaming in building needed housing and plans

7980-493: The state of Michigan. The lower Pigeon River is home to the federally endangered Indiana Bat. In 1969, the Michigan Department of Natural Resources began stocking the lower 23 miles (37 km) of the river for steelhead trout ( Oncorhynchus mykiss ), Chinook salmon ( Oncorhynchus tshawytscha ) and coho salmon ( Oncorhynchus kisutch ). In 1975, Michigan constructed a fish ladder at the Berrien Springs Dam to enable

8075-508: The straight-fin it was 44 °C, or 6 °C better than the pin fin. Pin fin heat sink performance is significantly better than straight fins when used in their optimal application where the fluid flows axially along the pins rather than only tangentially across the pins. Cavities (inverted fins) embedded in a heat source are the regions formed between adjacent fins that stand for the essential promoters of nucleate boiling or condensation. These cavities are usually utilized to extract heat from

8170-489: The temperature nodes shown in the diagram gives the following set of equations: where Using the mean air temperature is an assumption that is valid for relatively short heat sinks. When compact heat exchangers are calculated, the logarithmic mean air temperature is used. The above equations show that: Natural convection requires free flow of air over the heat sink. If fins are not aligned vertically, or if fins are too close together to allow sufficient air flow between them,

8265-435: The temperature of the device or component will depend on the thermal resistance from the component to the environment, and the heat dissipated by the component. To ensure that the component does not overheat , a thermal engineer seeks to find an efficient heat transfer path from the device to the environment. The heat transfer path may be from the component to a printed circuit board (PCB), to a heat sink, to air flow provided by

8360-456: The thermal conductivity does not take into account the interface resistances. Therefore, if a TIM has a high thermal conductivity, it does not necessarily mean that the interface resistance will be low. Selection of a TIM is based on three parameters: the interface gap which the TIM must fill, the contact pressure, and the electrical resistivity of the TIM. The contact pressure is the pressure applied to

8455-522: The thermal conductivity of aluminium, around 400 W/(m·K) for pure copper. Its main applications are in industrial facilities, power plants, solar thermal water systems, HVAC systems, gas water heaters, forced air heating and cooling systems, geothermal heating and cooling, and electronic systems. Copper is three times as dense and more expensive than aluminium, and copper is less ductile than aluminum. One-piece copper heat sinks can be made by skiving or milling . Sheet-metal fins can be soldered onto

8550-410: The thermal performance is at least 20% better than straight fin heat sinks. Lasance and Eggink also found that for the bypass configurations that they tested, the flared heat sink performed better than the other heat sinks tested. Generally, the more surface area a heat sink has, the better its performance. Real-world performance depends on the design and application. The concept of a pin fin heat sink

8645-433: The threaded standoff and compression spring attachment method. A threaded standoff is essentially a hollow metal tube with internal threads. One end is secured with a screw through a hole in the PCB. The other end accepts a screw which compresses the spring, completing the assembly. A typical heat sink assembly uses two to four standoffs, which tends to make this the most costly heat sink attachment design. Another disadvantage

8740-545: The virgin forests were mostly logged, and the prairies largely converted to agricultural use, as were many drained wetlands. Among the unique natural features that remain in the watershed are prairie fens , coastal plain marshes, bogs , floodplain forests, hardwood swamps, and moist hardwood forests. Rare plants include prairie dropseed ( Sporobolus heterolepis ), rosinweed, tall beak rush, and umbrella grass. The wetlands and floodplain forests provide habitat to nearly half of all migratory birds in Indiana and Michigan and are

8835-605: The water power rights on the West Race canal, while Samuel L. Cottrell purchased the water rights along the East Race canal. In 1867 the South Bend Hydraulic Company purchased the rights to the East Race canal for $ 100. In 1903 the ownership of stock, property rights, and property of the South Bend Manufacturing Company on the West Race canal passed to the Oliver Chilled Plow Works . Over the next two years

8930-399: The z-clips, the printed circuit board must have anchors. Anchors can be either soldered onto the board, or pushed through. Either type requires holes to be designed into the board. The use of RoHS solder must be allowed for because such solder is mechanically weaker than traditional Pb/Sn solder. To assemble with a z-clip , attach one side of it to one of the anchors. Deflect the spring until

9025-554: Was called by the Miami people, was inhabited for thousands of years by various indigenous tribes as it served an essential trade avenue in the Great Lakes region. The most recent indigenous inhabitants of the area were the Miami and Potawatomi peoples. Two different portages allowed nearly continuous travel by canoe among different watersheds of the region. The first major transfer point was at

#25974