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108-622: The Beijing Weather Modification Office form a part of China's nationwide weather control effort, believed to be the world's largest; it employs 37,000 people nationwide, who seed clouds by firing rockets and shells loaded with silver iodide into them. According to Zhang Qiang, head of the Office, cloud seeding increased precipitation in Beijing by about one-eighth in 2004; nationwide, similar efforts added 210 cubic kilometres (7.4 × 10 ^  cu ft) of rain between 1995 and 2003. The work of

216-474: A crystalline structure like ice. In mid-altitude clouds, the usual seeding strategy has been based on the fact that the equilibrium vapor pressure is lower over ice than over water. The formation of ice particles in supercooled clouds allows those particles to grow at the expense of liquid droplets. If sufficient growth takes place, the particles become heavy enough to fall as precipitation from clouds that otherwise would produce no precipitation. This process

324-413: A boost, where it is added through the turbocharger, to mix with diesel fuel droplets. Propane droplets' very high hydrogen content helps the diesel fuel to burn hotter and therefore more completely. This provides more torque, more horsepower, and a cleaner exhaust for the trucks. It is normal for a 7-liter medium-duty diesel truck engine to increase fuel economy by 20 to 33 percent when a propane boost system

432-457: A chimney, (known as lower heating value ) is −2043.455 kJ/mol. The lower heat value is the amount of heat available from burning the substance where the combustion products are vented to the atmosphere; for example, the heat from a fireplace when the flue is open. The density of propane gas at 25 °C (77 °F) is 1.808 kg/m , about 1.5× the density of air at the same temperature. The density of liquid propane at 25 °C (77 °F)

540-576: A cloud seeding project, created in response to lower water levels for hydroelectric power due to dry weather. In February of that year, a group of officials from the SLAF, Ceylon Electricity Board , and meteorology and irrigation departments were sent to Thailand to study rainmaking projects carried out by the Department of Royal Rainmaking and Agricultural Aviation . On March 22, a Harbin Y-12 flew over

648-466: A few experiments at GE's Schenectady Research Lab. He was dismayed to find that the deep freezer was not cold enough to produce a "cloud" using breath air. He decided to move the process along by adding a chunk of dry ice just to lower the temperature of his experimental chamber. To his astonishment, as soon as he breathed into the deep freezer, he noted a bluish haze, followed by an eye-popping display of millions of microscopic ice crystals, reflecting

756-639: A flight that began in upstate New York on 13 November 1946. Schaefer was able to cause snow to fall near Mount Greylock in western Massachusetts after he dumped six pounds (2.5 kg) of dry ice into the target cloud from a plane after a 60-mile (100 km) easterly chase from the Schenectady County Airport . Dry ice and silver iodide agents are effective in changing super-cooled clouds' physical chemistry, and thus useful in augmenting winter snowfall over mountains and, under certain conditions, in lightning and hail suppression. While not

864-435: A gas, has also been used. It can produce ice crystals at higher temperatures than silver iodide. After promising research, the use of hygroscopic materials, such as table salt , is becoming more popular. When cloud seeding, increased snowfall takes place when temperatures within the clouds are between −20 and −7 °C. Freezing nucleation is induced by the introduction of substances similar to silver iodide, which has

972-456: A gas, very high pressure is required to store useful quantities. This poses the hazard that, in an accident, just as with any compressed gas cylinder (such as a CO 2 cylinder used for a soda concession) a CNG cylinder may burst with great force, or leak rapidly enough to become a self-propelled missile. Therefore, CNG is much less efficient to store than propane, due to the large cylinder volume required. An alternative means of storing natural gas

1080-472: A long enough time to show statistically any change from natural variations. An attempt by the U.S. military to modify hurricanes in the Atlantic basin using cloud seeding in the 1960s was called Project STORMFURY . Scientists tested four hurricanes across eight days and observed decreased wind speeds of 10% to 30% on four of these days. They originally attributed the lack of results to faulty execution, but

1188-515: A new technique, hygroscopic seeding for enhancement of rainfall in warm clouds is enjoying a revival, based on positive indications from research in South Africa, Mexico, and elsewhere. The hygroscopic material most commonly used is table salt. It is postulated that hygroscopic seeding causes the droplet size spectrum in clouds to become more maritime (bigger drops) and less continental, stimulating rainfall through coalescence. From 1967 to 1972,

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1296-516: A payload of electric-charge emission instruments and customized sensors that fly at low altitudes and deliver an electric charge to air molecules. This method produced a significant rainstorm in July 2021. For instance, in Al Ain it rained 6.9 millimeters on 20–21 July. An electronic mechanism was tested in 2010, when infrared laser pulses were directed to the air above Berlin by researchers from

1404-469: A popular choice for barbecues and portable stoves because its low −42 °C boiling point makes it vaporise inside pressurised liquid containers (it exists in two phases, vapor above liquid). It retains its ability to vaporise even in cold weather, making it better-suited for outdoor use in cold climates than alternatives with higher boiling points like butane. LPG powers buses, forklifts, automobiles, outboard boat motors, and ice resurfacing machines , and

1512-399: A significant risk of fire or explosion. Vendors and advocates of hydrocarbon refrigerants argue against such bans on the grounds that there have been very few such incidents relative to the number of vehicle air conditioning systems filled with hydrocarbons. Propane is also instrumental in providing off-the-grid refrigeration, as the energy source for a gas absorption refrigerator and

1620-519: A snowstorm in November 2009. This People's Republic of China -related article is a stub . You can help Misplaced Pages by expanding it . Cloud seeding Cloud seeding is a type of weather modification that aims to change the amount or type of precipitation , mitigate hail or disperse fog. The usual objective is to increase rain or snow, either for its own sake or to prevent precipitation from occurring in days afterward. Cloud seeding

1728-465: A study to gauge its viability locally. In Southeast Asia , open-burning haze pollutes the regional environment. Cloud seeding has been used to improve the air quality by encouraging rainfall. On 20 June 2013, Indonesia said it will begin cloud-seeding operations following reports from Singapore and Malaysia that smog caused by forest and bush fires in Sumatra have disrupted daily activities in

1836-422: A visible flame. The enthalpy of combustion of propane gas where all products return to standard state, for example where water returns to its liquid state at standard temperature (known as higher heating value ), is (2,219.2 ± 0.5) kJ/mol, or (50.33 ± 0.01) MJ/kg. The enthalpy of combustion of propane gas where products do not return to standard state, for example where the hot gases including water vapor exit

1944-533: Is "difficult to show clearly that cloud seeding has a very large effect". Environmental and health impacts are considered minimal due to the low concentrations of substances used. But concerns persist over the potential accumulation of seeding agents in sensitive ecosystems. The practice has a long history, with initial experiments dating back to the 1940s, and has been used for various purposes, including agricultural benefits, water supply augmentation, and event planning. Legal frameworks primarily focus on prohibiting

2052-438: Is 0.493 g/cm , which is equivalent to 4.11 pounds per U.S. liquid gallon or 493 g/L. Propane expands at 1.5% per 10 °F. Thus, liquid propane has a density of approximately 4.2 pounds per gallon (504 g/L) at 60 °F (15.6 °C). As the density of propane changes with temperature, this fact must be considered every time when the application is connected with safety or custody transfer operations. Propane

2160-415: Is a popular choice for barbecues and portable stoves because the low boiling point of −42 °C (−44 °F) makes it vaporize as soon as it is released from its pressurized container. Therefore, no carburetor or other vaporizing device is required; a simple metering nozzle suffices. Blends of pure, dry "isopropane" [isobutane/propane mixtures of propane (R-290) and isobutane (R-600a)] can be used as

2268-486: Is a simple asphyxiant . Unlike natural gas , it is denser than air. It may accumulate in low spaces and near the floor. When abused as an inhalant , it may cause hypoxia (lack of oxygen), pneumonia , cardiac failure or cardiac arrest . Propane has low toxicity since it is not readily absorbed and is not biologically active . Commonly stored under pressure at room temperature, propane and its mixtures will flash evaporate at atmospheric pressure and cool well below

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2376-524: Is as a cryogenic liquid in an insulated container as liquefied natural gas (LNG). This form of storage is at low pressure and is around 3.5 times as efficient as storing it as CNG. Unlike propane, if a spill occurs, CNG will evaporate and dissipate because it is lighter than air. Propane is much more commonly used to fuel vehicles than is natural gas, because that equipment costs less. Propane requires just 1,220 kilopascals (177 psi) of pressure to keep it liquid at 37.8 °C (100 °F). Propane

2484-581: Is commonly used for camping and recreational vehicles. It has also been proposed to use propane as a refrigerant in heat pumps . Since it can be transported easily, it is a popular fuel for home heat and backup electrical generation in sparsely populated areas that do not have natural gas pipelines. In June 2023, Stanford researchers found propane combustion emitted detectable and repeatable levels of benzene that in some homes raised indoor benzene concentrations above well-established health benchmarks. The research also shows that gas and propane fuels appear to be

2592-454: Is delivered to end-users via small or medium-sized individual cylinders, while empty cylinders are removed for refilling at a central location. There are also community propane systems, with a central cylinder feeding individual homes. In the U.S., over 190,000 on-road vehicles use propane, and over 450,000 forklifts use it for power. It is the third most popular vehicle fuel in the world, behind gasoline and diesel fuel . In other parts of

2700-467: Is far less than current refrigerants, propane was chosen as one of five replacement refrigerants approved by the EPA in 2015, for use in systems specially designed to handle its flammability. Such substitution is widely prohibited or discouraged in motor vehicle air conditioning systems, on the grounds that using flammable hydrocarbons in systems originally designed to carry non-flammable refrigerant presents

2808-455: Is known as "static" seeding. Seeding of warm-season or tropical cumulonimbus (convective) clouds seeks to exploit the latent heat released by freezing. This strategy of "dynamic" seeding assumes that the additional latent heat adds buoyancy, strengthens updrafts, ensures more low-level convergence, and ultimately causes rapid growth of properly selected clouds. Cloud seeding chemicals may be dispersed by aircraft or by dispersion devices on

2916-544: Is known as a BLEVE or boiling liquid expanding vapor explosion . The Kingman Explosion involved a railroad tank car in Kingman, Arizona, U.S., in 1973 during a propane transfer. The fire and subsequent explosions resulted in twelve fatalities and numerous injuries. Propane is produced as a by-product of two other processes, natural gas processing and petroleum refining . The processing of natural gas involves removal of butane , propane, and large amounts of ethane from

3024-457: Is much cleaner than that of coal or unleaded gasoline. Propane's per-BTU production of CO 2 is almost as low as that of natural gas. Propane burns hotter than home heating oil or diesel fuel because of the very high hydrogen content. The presence of C–C bonds , plus the multiple bonds of propylene and butylene , produce organic exhausts besides carbon dioxide and water vapor during typical combustion. These bonds also cause propane to burn with

3132-525: Is not suited for most vehicle fuels. HD-5 is a specification that establishes a maximum concentration of 5% propene in propane. Propane and other LP gas specifications are established in ASTM D-1835. All propane fuels include an odorant , almost always ethanethiol , so that the gas can be smelled easily in case of a leak. Propane as HD-5 was originally intended for use as vehicle fuel. HD-5 is currently being used in all propane applications. Typically in

3240-726: Is often a constituent of liquefied petroleum gas (LPG), which is commonly used as a fuel in domestic and industrial applications and in low-emissions public transportation; other constituents of LPG may include propylene , butane , butylene , butadiene , and isobutylene . Discovered in 1857 by the French chemist Marcellin Berthelot , it became commercially available in the US by 1911. Propane has lower volumetric energy density than gasoline or coal, but has higher gravimetric energy density than them and burns more cleanly. Propane gas has become

3348-741: Is present for complete combustion, carbon monoxide , soot ( carbon ), or both, are formed as well: C 3 H 8 + 9 2 O 2 ⟶ 2 CO 2 + CO + 4 H 2 O + heat {\displaystyle {\ce {C3H8 + 9/2 O2 -> 2 CO2 + CO + 4 H2O + heat}}} C 3 H 8 + 2 O 2 ⟶ 3 C + 4 H 2 O + heat {\displaystyle {\ce {C3H8 + 2 O2 -> 3 C + 4 H2O + heat}}} The complete combustion of propane produces about 50 MJ/kg of heat. Propane combustion

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3456-519: Is rated HD-5 (Heavy Duty 5%). HD-5 grade has a maximum of 5 percent butane, but propane sold in Europe has a maximum allowable amount of butane of 30 percent, meaning it is not the same fuel as HD-5. The LPG used as auto fuel and cooking gas in Asia and Australia also has very high butane content. Propylene (also called propene) can be a contaminant of commercial propane. Propane containing too much propene

3564-537: Is that theft is much more difficult than with gasoline or diesel fuels. Propane is also used as fuel for small engines , especially those used indoors or in areas with insufficient fresh air and ventilation to carry away the more toxic exhaust of an engine running on gasoline or diesel fuel. More recently, there have been lawn-care products like string trimmers , lawn mowers and leaf blowers intended for outdoor use, but fueled by propane in order to reduce air pollution . Many heavy-duty highway trucks use propane as

3672-411: Is unable to say with assurance which, if any, seeding techniques produce positive effects. In the 55 years following the first cloud-seeding demonstrations, substantial progress has been made in understanding the natural processes that account for our daily weather. Yet scientifically acceptable proof for significant seeding effects has not been achieved". A 2010 Tel Aviv University study claimed that

3780-486: Is undertaken by dispersing substances into the air that serve as cloud condensation or ice nuclei . Common agents include silver iodide , potassium iodide , and dry ice, with hygroscopic materials like table salt gaining popularity due to their ability to attract moisture. Techniques vary from static seeding, which encourages ice particle formation in supercooled clouds to increase precipitation, to dynamic seeding, designed to enhance convective cloud development through

3888-610: Is used for heat and cooking in recreational vehicles and campers . Propane is becoming popular as a replacement refrigerant (R290) for heatpumps also as it offers greater efficiency than the current refrigerants: R410A / R32, higher temperature heat output and less damage to the atmosphere for escaped gasses - at the expense of high gas flammability. Propane was first synthesized by the French chemist Marcellin Berthelot in 1857 during his researches on hydrogenation . Berthelot made propane by heating propylene dibromide (C 3 H 6 Br 2 ) with potassium iodide and water. Propane

3996-537: Is used. It is cheaper because propane is much cheaper than diesel fuel. The longer distance a cross-country trucker can travel on a full load of combined diesel and propane fuel means they can maintain federal hours of work rules with two fewer fuel stops in a cross-country trip. Truckers, tractor pulling competitions, and farmers have been using a propane boost system for over forty years in North America. The North American standard grade of automotive-use propane

4104-643: The Eureka organization in 2001 for an invention that is beneficial to the world. In 2009, Jordan received permission from Thailand to use the technique. On 12 October 2005 the European Patent Office granted to King Bhumibol Adulyadej the patent EP 1 491 088 Weather modification by royal rainmaking technology . The budget of the Department of Royal Rainmaking and Agricultural Aviation in FY2019

4212-471: The Maskeliya Reservoir at 8000 feet, dispersing cloud seeding chemicals. Rain arrived the next day on March 23, though project members had expected it to appear earlier on the 22nd. News First proclaimed that the pilot project had "proven to be a success", while Mongabay described it as a "failed attempt" that had "fallen short" and highlighted various climate experts who recommended that

4320-681: The National Oceanic and Atmospheric Administration (NOAA; Department of Commerce). Reclamation sponsored several cloud-seeding research projects under the umbrella of Project Skywater from 1964 to 1988, and NOAA conducted the Atmospheric Modification Program from 1979 to 1993. The sponsored projects were carried out in several states and two countries (Thailand and Morocco), studying both winter and summer cloud seeding. From 1962 to 1988 Reclamation developed cloud seeding applied research to augment water supplies in

4428-504: The University of Geneva . The experimenters posited that the pulses would encourage atmospheric sulfur dioxide and nitrogen dioxide to form particles that would then act as seeds. Whether cloud seeding is effective in producing a statistically significant increase in precipitation is a matter of academic debate, with contrasting results depending on the study in question and contrasting opinion among experts. A study conducted by

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4536-435: The haze began in early-August. Johor Water Regulatory Body is focus to produce rain over dams with critically low water levels. They use Cessna 340 with tubes of ioidise salt their operation base is at Senai Airport WMKJ. The Thailand Royal Rainmaking Project ( Thai : โครงการฝนหลวง , RTGS :  khrongkan fon luang ) was initiated in November 1955 by King Bhumibol Adulyadej . Thai farmers repeatedly suffered

4644-559: The pygmy possum , among other species, as well as recent high-level algal blooms in once pristine glacial lakes. Research 50 years ago and analysis by the former Snowy Mountains Authority led to the cessation of the cloud seeding program in the 1950s with non-definitive results. Formerly, cloud seeding was rejected in Australia on environmental grounds because of concerns about the pygmy possum. The claims of negative environmental impact are disputed by peer-reviewed research, as summarized by

4752-779: The revolution of 1978, in the years 1989 to 1995, cloud fertilization was carried out in a scattered manner using ground generators in the heights of Shirkuh, Yazd. Then, with the announcement of the Minister of Energy in February 1996, the National Center for Cloud Fertility Research and Studies was established in Yazd and officially started working in 1997. Israel conducted experimental cloud seeding for seven years from 2014 to 2021. The practice involved emitting silver iodide from airplanes and ground stations and took place only in

4860-643: The space group P2 1 /n. The low space-filling of 58.5% (at 90 K), due to the bad stacking properties of the molecule, is the reason for the particularly low melting point. Propane undergoes combustion reactions in a similar fashion to other alkanes . In the presence of excess oxygen, propane burns to form water and carbon dioxide . C 3 H 8 + 5 O 2 ⟶ 3 CO 2 + 4 H 2 O + heat {\displaystyle {\ce {C3H8 + 5 O2 -> 3 CO2 + 4 H2O + heat}}} When insufficient oxygen

4968-510: The 1930s included the introduction of railroad tank car transport, gas odorization, and the construction of local bottle-filling plants. The year 1945 marked the first year that annual LP gas sales reached a billion gallons. By 1947, 62% of all U.S. homes had been equipped with either natural gas or propane for cooking. In 1950, 1,000 propane-fueled buses were ordered by the Chicago Transit Authority , and by 1958, sales in

5076-550: The 2008 Olympic Games in order to have a dry Olympic season. In February 2009, China also blasted iodide sticks over Beijing to artificially induce snowfall after four months of drought, and blasted iodide sticks over other areas of northern China to increase snowfall. The snowfall in Beijing lasted for approximately three days and led to the closure of 12 main roads around Beijing. At the end of October 2009 Beijing claimed it had its earliest snowfall since 1987 due to cloud seeding. According to "research paper from Tsinghua University,

5184-662: The Bureau of Reclamation sponsored a six-state research program from 2002 to 2006 called the "Weather Damage Modification Program". A 2003 study by the United States National Academy of Sciences urges a national research program to clear up remaining questions about weather modification's efficacy and practice. In Australia , the Commonwealth Scientific and Industrial Research Organisation (CSIRO) conducted major trials between 1947 and

5292-546: The Chinese government used cloud-seeding techniques to force rainfall the evening before the celebration event. This rainfall lowered the amount of PM2.5 pollution by more than two-thirds. That helped improve the air quality at the time from "moderate" to "good". In India , cloud seeding operations were conducted during the years 1983, 1984–87, and 1993–94 by the Tamil Nadu Government due to severe drought. In

5400-486: The Chinese weather authorities used weather modification to ensure the sky was clear and lower air pollution" on July 1, 2021. The Chinese Communist party celebrated its centenary on July 1 with a major celebration. The celebration took place in Tiananmen Square. The paper was published on November 26, 2021 in a peer-review journal called Environment Science (via South China Morning Post) . The research shows that

5508-475: The Clean Water Act of 1977 and 1987 to establish regulations on this type of pollution." Cloud seeding over Kosciuszko National Park  – a biosphere reserve – is problematic in that several rapid changes of environmental legislation were made to enable the trial. Environmentalists are concerned about the uptake of elemental silver in a highly sensitive environment affecting

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5616-605: The December 2015 EIA figure for the East Coast at $ 2.67 per gallon and the Midwest at $ 1.43 per gallon. As of August 2018 , the average US propane retail cost was approximately $ 2.48 per gallon. The wholesale price of propane in the U.S. always drops in the summer as most homes do not require it for home heating. The wholesale price of propane in the summer of 2018 was between 86 cents to 96 cents per U.S. gallon, based on

5724-626: The Desert Research Institute in Reno, claimed that new technology and research has produced reliable results that make cloud seeding a dependable and affordable water supply practice for many regions. Moreover, in 1998 the American Meteorological Society held that "precipitation from supercooled orographic clouds (clouds that develop over mountains) has been seasonally increased by about 10%." Despite

5832-541: The Energy Information Administration (EIA) quotes a $ 2.995 per gallon average on the East Coast for October 2013, while the figure for the Midwest was $ 1.860 for the same period. As of December 2015 , the propane retail cost was approximately $ 1.97 per gallon, which meant filling a 500-gallon propane tank to 80% capacity costed $ 788, a 16.9% decrease or $ 160 less from November 2013. Similar regional differences in prices are present with

5940-614: The International Weather Modification Association. In 1891, Louis Gathmann suggested shooting liquid carbon dioxide into rain clouds to cause them to rain. During the 1930s, the Bergeron–Findeisen process theorized that supercooled water droplets present, while ice crystals are released into rain clouds, would cause rain. While researching aircraft icing , General Electric (GE)'s Vincent Schaefer and Irving Langmuir confirmed

6048-566: The Law on Water and its Nationalization, the then Ministry of Water and Electricity was obliged to provide the water needed by the country in various ways, including cloud fertilization. Accordingly, the Ministry of Energy between 1953 and 1957, in cooperation with a Canadian company and using aircraft and silver iodide compound fertilized the clouds that were over the Karaj and Jajrud dam area. After

6156-709: The NAS study was acquired in a separate study conducted by the Wyoming Weather Modification Pilot Project, but whereas the NAS study concluded that "it is difficult to show clearly that cloud seeding has a very large effect", the WWMPP study concluded that "seeding could augment the snowpack by a maximum of 3% over an entire season." In 2003, the US National Research Council (NRC) released a report stating, "science

6264-451: The Office is largely aimed at hail storm prevention or making rain to end droughts; they have also induced precipitation for purposes of firefighting or counteracting the effect of severe dust storms , as they did in the aftermath of one storm in April 2006 which dropped 300,000 tonnes of dust and sand on the city and was believed to have been the largest in five years. Their technology

6372-534: The Sierra Nevada of California and a 2004 independent panel of experts in Australia confirmed these earlier findings. "In 1978, an estimated 3,000 tonnes of silver were released into the US environment. This led the US Health Services and EPA to conduct studies regarding the potential for environmental and human health hazards related to silver. These agencies and other state agencies applied

6480-584: The U.S. had reached 7 billion US gallons (26,000,000 m ) annually. In 2004, it was reported to be a growing $ 8-billion to $ 10-billion industry with over 15 billion US gallons (57,000,000 m ) of propane being used annually in the U.S. During the COVID-19 pandemic , propane shortages were reported in the United States due to increased demand. The " prop- " root found in "propane" and names of other compounds with three-carbon chains

6588-518: The U.S. military's Operation Popeye cloud-seeded silver iodide to extend the monsoon season over North Vietnam , specifically the Ho Chi Minh Trail . The operation extended the monsoon period an average of 30 to 45 days in the targeted areas. The 54th Weather Reconnaissance Squadron carried out the operation to "make mud, not war". One private organization that offered, during the 1970s, to conduct weather modification (cloud seeding from

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6696-496: The United States National Academy of Sciences failed to find statistically significant support for cloud seeding's effectiveness. Based on its findings, Stanford University ecologist Jerry Bradley said: "I think you can squeeze out a little more snow or rain in some places under some conditions, but that's quite different from a program claiming to reliably increase precipitation." Data similar to that of

6804-759: The United States and Canada, LPG is primarily propane (at least 90%), while the rest is mostly ethane , propylene , butane , and odorants including ethyl mercaptan . This is the HD-5 standard, (maximum allowable propylene content, and no more than 5% butanes and ethane) defined by the American Society for Testing and Materials by its Standard 1835 for internal combustion engines. Not all products labeled "LPG" conform to this standard, however. In Mexico, for example, gas labeled "LPG" may consist of 60% propane and 40% butane. "The exact proportion of this combination varies by country, depending on international prices, on

6912-614: The Universities of Wyoming, Washington, UCLA, Utah, Chicago, NYU, Montana, and Colorado, and research teams at Stanford, Meteorology Research Inc., and Penn State University, and the South Dakota School of Mines and Technology, North Dakota, Texas A&M, Texas Tech, and Oklahoma. Cooperative efforts with state water resources agencies in California, Colorado, Montana, Kansas, Oklahoma, Texas, and Arizona assured that

7020-503: The applied research met state water management needs. HIPLEX also partnered with NASA, Environment Canada, and the National Center for Atmospheric Research ( NCAR ). From 2002 to 2006, in cooperation with six western states, Reclamation sponsored a small cooperative research program called the Weather Damage Modification Program. In the U.S., funding for research has declined in the last two decades. But

7128-432: The availability of components and, especially, on the climatic conditions that favor LPG with higher butane content in warmer regions and propane in cold areas". Propane is bought and stored in a liquid form, LPG. It can easily be stored in a relatively small space. By comparison, compressed natural gas (CNG) cannot be liquefied by compression at normal temperatures, as these are well above its critical temperature . As

7236-580: The circulating refrigerant in suitably constructed compressor-based refrigeration. Compared to fluorocarbons, propane has a negligible ozone depletion potential and very low global warming potential (having a GWP value of 0.072, 13.9 times lower than the GWP of carbon dioxide) and can serve as a functional replacement for R-12 , R-22 , R-134a , and other chlorofluorocarbon or hydrofluorocarbon refrigerants in conventional stationary refrigeration and air conditioning systems. Because its global warming effect

7344-559: The common practice of cloud seeding to improve rainfall, with materials such as silver iodide and frozen carbon dioxide, seems to have little if any impact on the amount of precipitation. A 2011 study suggested that airplanes may produce ice particles by freezing cloud droplets that cool as they flow around the tips of propellers, over wings or over jet aircraft, and thereby unintentionally seed clouds. This could have potentially serious consequences for particular hail stone formation. In 2016, Jeff Tilley, director of weather modification at

7452-619: The dominant source of benzene produced by cooking. In rural areas of North America, as well as northern Australia, propane is used to heat livestock facilities, in grain dryers, and other heat-producing appliances. When used for heating or grain drying it is usually stored in a large, permanently-placed cylinder which is refilled by a propane-delivery truck. As of 2014 , 6.2 million American households use propane as their primary heating fuel. In North America, local delivery trucks with an average cylinder size of 3,000 US gallons (11 m ), fill up large cylinders that are permanently installed on

7560-640: The early-1960s: Only the trial conducted in the Snowy Mountains produced statistically significant rainfall increases over the entire experiment. Hydro Tasmania (at the time still known as the Hydro Electric Commission) began experimenting with cloud-seeding over lake catchments in central Tasmania in the early 1960s in order to determine if their electricity-producing dams could be kept at high water levels through cloud seeding. Tasmania proved to be one place where cloud seeding

7668-478: The effects of drought. The king resolved to do something about it and proposed a solution to the dearth of rain: artificial rainmaking , or cloud seeding. The program is run by the Department of Royal Rainmaking and Agricultural Aviation. Thailand started a rain-making project in the late-1950s, known today as the Royal Rainmaking Project . Its first efforts scattered sea salt in the air to catch

7776-577: The floor to the pilot light on the furnace or water heater, and results in an explosion or fire. This property makes propane generally unsuitable as a fuel for boats. In 2007, a heavily investigated vapor-related explosion occurred in Ghent, West Virginia, U.S., killing four people and completely destroying the Little General convenience store on Flat Top Road , causing several injuries. Another hazard associated with propane storage and transport

7884-408: The freezing point of water. The cold gas, which appears white due to moisture condensing from the air, may cause frostbite. Propane is denser than air. If a leak in a propane fuel system occurs, the vaporized gas will have a tendency to sink into any enclosed area and thus poses a risk of explosion and fire. The typical scenario is a leaking cylinder stored in a basement; the propane leak drifts across

7992-426: The government conduct more research into the project's potential environmental effects before proceeding further. Liquid propane Propane ( / ˈ p r oʊ p eɪ n / ) is a three- carbon alkane with the molecular formula C 3 H 8 . It is a gas at standard temperature and pressure , but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it

8100-482: The ground (generators or canisters fired from anti-aircraft guns or rockets ). For release by aircraft, silver iodide flares are ignited and dispersed as an aircraft flies through the inflow of a cloud. When released by devices on the ground, the fine particles are carried downwind and upward by air currents after release. Since 2021, the United Arab Emirates have been using drones equipped with

8208-488: The ground using silver iodide flares) was Irving P. Krick and Associates of Palm Springs, California . They were contracted by Oklahoma State University in 1972 to conduct a seeding project to increase warm cloud rainfall in the Lake Carl Blackwell watershed . That lake was, at that time (1972–73), the primary water supply for Stillwater , Oklahoma , and was dangerously low. The project did not operate for

8316-659: The growing season in Montana, Kansas, and Texas from 1974 to 1979. In 1979, the World Meteorological Organization and other member-states led by the Government of Spain conducted a Precipitation Enhancement Project (PEP) in Spain, with inconclusive results due probably to location selection issues. Reclamation sponsored research at several universities, including Colorado State University,

8424-531: The humidity and dry ice to condense the humidity to form clouds. The project took about ten years of experiments and refinement. The first field operations began in 1969 above Khao Yai National Park . Since then the Thai government claims that rainmaking has been successfully applied throughout Thailand and neighboring countries. The king received recognition for the Royal Rainmaking Project from

8532-507: The military or hostile use of weather modification techniques, leaving the ownership and regulation of cloud-seeding activities to national discretion. Despite skepticism and debate over its efficacy and environmental impact, cloud seeding continues to be explored and applied in regions worldwide as a tool for weather modification. The most common chemicals used for cloud seeding include silver iodide , potassium iodide and dry ice (solid carbon dioxide). Liquid propane , which expands into

8640-818: The mixed scientific results, cloud seeding was attempted during the 2008 Summer Olympics in Beijing to coax rain showers out of clouds before they reached the city in order to prevent rain during the opening and closing ceremonies. Whether this attempt was successful is a matter of dispute, with Roelof Bruintjes, who leads the National Center for Atmospheric Research's weather-modification group, remarking, "we cannot make clouds or chase clouds away". With an NFPA 704 health hazard rating of 2, silver iodide can cause temporary incapacitation or possible residual injury to humans and other mammals with intense or chronic exposure. But several detailed ecological studies have shown negligible environmental and health impacts. The toxicity of silver and silver compounds (from silver iodide)

8748-536: The neighboring countries. On 25 June 2013, hailstones were reported to have fallen over some parts of Singapore. Despite NEA denials, some believe that the hailstones are the result of cloud seeding in Indonesia. In Malaysia, cloud seeding was first used in 1988 for three purposes: filling up dams, lessening the effects of haze, and fighting forest fires. In 2015, cloud seeding was done daily in Malaysia since

8856-437: The northern parts of the country. Israel stopped the rain enhancement project in 2021 due to the experiment data showing that the practice was largely ineffective and expensive, and because there had been some recent years of unrelated significant rainfall. To counter drought and a growing population in a desert region, Kuwait is embarking on its own cloud seeding program, with the local Environment Public Authority conducting

8964-503: The outbreak of the battle, and a test commenced the following month. Results were disappointing; while it did not take long for the rain clouds to form and release precipitation, they often drifted away from Route Provinciale 41 in the process, reducing their ability to hinder Việt Minh logistics. In January 2019, the Sri Lanka Air Force (SLAF) and Ministry of Power, Energy and Business Development signed an agreement for

9072-538: The pilots the cloud that has a high concentration of super cooled liquid water. The aircraft will find the altitude where the temperatures are about -5 °C. This is the altitude at which the seeding agent is most active. Pakistan has undergone its first-ever artificial rain experiment using cloud seeding, in a move carried out with the help of the United Arab Emirates Punjab Chief Minister Mohsin Naqvi said there

9180-511: The propane consumed each year, with about 70% of that coming from Canada via pipeline and rail. The remaining 30% of imported propane comes to the United States from other sources via ocean transport. After it is separated from the crude oil, North American propane is stored in huge salt caverns . Examples of these are Fort Saskatchewan , Alberta ; Mont Belvieu, Texas ; and Conway, Kansas . These salt caverns can store 80,000,000 barrels (13,000,000 m ) of propane. As of October 2013 ,

9288-521: The property, or other service trucks exchange empty cylinders of propane with filled cylinders. Large tractor-trailer trucks, with an average cylinder size of 10,000 US gallons (38 m ), transport propane from the pipeline or refinery to the local bulk plant. The bobtail tank truck is not unique to the North American market, though the practice is not as common elsewhere, and the vehicles are generally called tankers . In many countries, propane

9396-425: The raw gas, to prevent condensation of these volatiles in natural gas pipelines. Additionally, oil refineries produce some propane as a by-product of cracking petroleum into gasoline or heating oil. The supply of propane cannot easily be adjusted to meet increased demand, because of the by-product nature of propane production. About 90% of U.S. propane is domestically produced. The United States imports about 10% of

9504-483: The release of latent heat . Methods of dispersion include aircraft and ground-based generators, with newer approaches involving drones delivering electric charges to stimulate rainfall, or infrared laser pulses aimed at inducing particle formation. Despite decades of research and application, cloud seeding's effectiveness remains a subject of debate among scientists, with studies offering mixed results on its impact on precipitation enhancement. Some studies suggest it

9612-468: The results came into question because of the lack of supercooled water in the hurricane and the inability to determine if the effects were due to human intervention or the natural processes of hurricanes. Two federal agencies have supported various weather modification research projects, which began in the early 1960s: The United States Bureau of Reclamation (Reclamation; Department of the Interior) and

9720-437: The retail cost of propane was approximately $ 2.37 per gallon, or roughly $ 25.95 per 1 million BTUs. This means that filling a 500-gallon propane tank, which is what households that use propane as their main source of energy usually require, cost $ 948 (80% of 500 gallons or 400 gallons), a 7.5% increase on the 2012–2013 winter season average US price. However, propane costs per gallon change significantly from one state to another:

9828-489: The state of New York. Schaefer's method altered a cloud's heat budget; Vonnegut's altered formative crystal structure, an ingenious property related to a good match in lattice constant between the two types of crystal . (The crystallography of ice later played a role in Vonnegut's brother Kurt Vonnegut 's novel Cat's Cradle ). The first attempt to modify natural clouds in the field through "cloud seeding" began during

9936-414: The strong light rays from the lamp illuminating a cross-section of the chamber. He instantly realized that he had discovered a way to change super-cooled water into ice crystals. The experiment was easily replicated, and he explored the temperature gradient to establish the −40 °C (−40 °F) limit for liquid water. Within the month, Schaefer's colleague, the atmospheric scientist Bernard Vonnegut ,

10044-606: The technique is still actively deployed there. The largest cloud seeding system is in the People's Republic of China . They believe that it increases the amount of rain over several increasingly arid regions, including its capital city, Beijing , by firing silver iodide rockets into the sky where rain is desired. There is even political strife caused by neighboring regions that accuse each other of "stealing rain" using cloud seeding. China used cloud seeding in Beijing just before

10152-580: The theory. Schaefer discovered the principle of cloud seeding in July 1946 through a series of serendipitous events. Following ideas he and Langmuir generated while climbing Mt. Washington in New Hampshire, Schaefer, Langmuir's research associate, created a way of experimenting with supercooled clouds using a deep freeze unit of potential agents to stimulate ice crystal growth, i.e., table salt, talcum powder, soils, dust, and various chemical agents with minor effect. Then, on July 14, 1946, he wanted to try

10260-927: The western U.S. The research focused on winter orographic seeding to enhance snowfall in the Rocky Mountains and Sierra Nevada, and precipitation in coast ranges of southern California. In California Reclamation partnered with the California Department of Water Resources ( CDWR ) to sponsor the Serra Cooperative Pilot Project (SCPP), based in Auburn , to conduct seeding experiments in the central Sierra. The University of Nevada and Desert Research Institute provided cloud physics, physical chemistry, and other field support. The High Plains Cooperative Pilot Project (HIPLEX) focused on convective cloud seeding to increase rainfall during

10368-547: The world, propane used in vehicles is known as autogas. In 2007, approximately 13 million vehicles worldwide use autogas. The advantage of propane in cars is its liquid state at a moderate pressure. This allows fast refill times, affordable fuel cylinder construction, and price ranges typically just over half that of gasoline. Meanwhile, it is noticeably cleaner (both in handling, and in combustion), results in less engine wear (due to carbon deposits) without diluting engine oil (often extending oil-change intervals), and until recently

10476-463: The years 2003 and 2004 Karnataka government initiated cloud seeding. Cloud seeding operations were also conducted in the same year through US-based Weather Modification Inc. in the state of Maharashtra . The company Srishti Aviation is actively involved in air defense with two Cessna 340 aircraft for its cloud seeding operations. On the ground at the radar facility the Meteorologist assigns

10584-644: Was 2,224 million baht . In Vietnam , during the leadup to and initial stages of the Battle of Điện Biên Phủ in 1954, the French Far East Expeditionary Corps looked into the possibility of using cloud seeding to impede Việt Minh flow of supplies through Route Provinciale 41, a dirt road leading into Điện Biên Phủ that would become more difficult to navigate during the rainy season . General Henri Navarre authorized research into using cloud seeding this way on March 16, just before

10692-446: Was also used to create snow on New Year's Day in 1997. Other proposed future uses for induced precipitation include lowering temperatures in summer, in hopes of reducing electricity consumption. More prominently, they were enlisted by the Chinese government to ensure that the 2008 Summer Olympics were free of rain, by breaking up clouds headed towards the capital and forcing them to drop rain on outlying areas instead. The office created

10800-553: Was credited with discovering another method for "seeding" super-cooled cloud water. Vonnegut accomplished his discovery at the desk, looking up information in a basic chemistry text and then tinkering with silver and iodide chemicals to produce silver iodide. Together with Professor Henry Chessin, of SUNY Albany , a crystallographer, he co-authored a publication in Science and received a patent in 1975. Both methods were adopted for use in cloud seeding during 1946 while working for GE in

10908-547: Was derived from " propionic acid ", which in turn was named after the Greek words protos (meaning first) and pion (fat), as it was the "first" member of the series of fatty acids . Propane is a colorless, odorless gas. Ethyl mercaptan is added as a safety precaution as an odorant , and is commonly called a "rotten egg" smell. At normal pressure it liquifies below its boiling point at −42 °C and solidifies below its melting point at −187.7 °C. Propane crystallizes in

11016-443: Was developed by Frank Peterson and its patent was granted on July 2, 1912. The 1920s saw increased production of LP gases, with the first year of recorded production totaling 223,000 US gallons (840 m ) in 1922. In 1927, annual marketed LP gas production reached 1 million US gallons (3,800 m ), and by 1935, the annual sales of LP gas had reached 56 million US gallons (210,000 m ). Major industry developments in

11124-654: Was drizzle in 'at least 10 areas' of Lahore, consistently ranked the most polluted city in the world. In Jakarta , cloud seeding was used to minimize flood risk in anticipation of heavy floods in 2013, according to the Agency for the Assessment and Application of Technology. In 1946, the Iranian government tried to fertilize Iran's clouds with the help of Americans, but it was unsuccessful. Then in 1947, in Article 19 of

11232-532: Was during this time that Snelling — in cooperation with Frank P. Peterson, Chester Kerr, and Arthur Kerr — developed ways to liquefy the LP gases during the refining of gasoline. Together, they established American Gasol Co., the first commercial marketer of propane. Snelling had produced relatively pure propane by 1911, and on March 25, 1913, his method of processing and producing LP gases was issued patent #1,056,845. A separate method of producing LP gas through compression

11340-663: Was found dissolved in Pennsylvanian light crude oil by Edmund Ronalds in 1864. Walter O. Snelling of the U.S. Bureau of Mines highlighted it as a volatile component in gasoline in 1910, which marked the "birth of the propane industry" in the United States. The volatility of these lighter hydrocarbons caused them to be known as "wild" because of the high vapor pressures of unrefined gasoline. On March 31, 1912, The New York Times reported on Snelling's work with liquefied gas, saying "a steel bottle will carry enough gas to light an ordinary home for three weeks". It

11448-475: Was highly effective. Various trials were undertaken between 1964 and 2005, and again between 2009 and 2016, but none have taken place since then. Hydro Tasmania also undertook soil and water survey samples and found negligible trace elements of the materials used for cloud seeding (such as silver iodine), and determined it did not have a detrimental effect on the environment. An Austrian study to use silver iodide seeding for hail prevention ran during 1981–2000, and

11556-467: Was relatively low-cost in North America. The octane rating of propane is relatively high at 110. In the United States the propane fueling infrastructure is the most developed of all alternative vehicle fuels. Many converted vehicles have provisions for topping off from "barbecue bottles". Purpose-built vehicles are often in commercially owned fleets, and have private fueling facilities. A further saving for propane fuel vehicle operators, especially in fleets,

11664-441: Was shown to be of low order in some studies. These findings likely result from the minute amounts of silver generated by cloud seeding, which are about one percent of industry emissions into the atmosphere in many parts of the world, or individual exposure from tooth fillings. Accumulations in the soil, vegetation, and surface runoff have not been large enough to measure above natural background. A 1995 environmental assessment in

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