Aqueduct (water supply)

An aqueduct is a watercourse constructed to carry water from a source to a distribution point far away. In modern engineering, the term aqueduct is used for any system of pipes, canals and other structures used for this purpose; the term aqueduct often refers to a bridge on an artificial watercourse. The word is derived from ducere. Aqueducts were used in ancient Greece, ancient Egypt, ancient Rome. In modern times, the largest aqueducts of all have been built in the United States to supply the country's biggest cities; the simplest aqueducts are small ditches cut into the earth. Much larger channels may be used in modern aqueducts. Aqueducts sometimes run for all of their path through tunnels constructed underground. Modern aqueducts may use pipelines. Agricultural societies have constructed aqueducts to irrigate crops and supply large cities with drinking water. Although associated with the Romans, aqueducts were devised much earlier in Greece and the Near East and Indian subcontinent, where peoples such as the Egyptians and Harappans built sophisticated irrigation systems.

Roman-style aqueducts were used as early as the 7th century BC, when the Assyrians built an 80 km long limestone aqueduct, which included a 10 m high section to cross a 300 m wide valley, to carry water to their capital city, Nineveh. The Indian subcontinent is believed to have some of the earliest aqueducts. Evidence can be found at the sites of Karnataka; the massive aqueducts near river Tungabhadra supplying irrigation water were once 15 miles long. The waterways supplied water to royal bath tubs. In Oman from the Iron Age, in Salut and other sites, a system of underground aqueducts called falaj or qanāts were constructed, a series of well-like vertical shafts, connected by sloping horizontal tunnels. There are three types of falaj: Daudi with underground aqueducts Ghaili requiring a dam to collect the water Aini whose source is a water springThese enabled large scale agriculture to flourish in a dry land environment. In Persia from early times a system of underground aqueducts called qanāts were constructed, a series of well-like vertical shafts, connected by sloping tunnels.

This technique: taps into subterranean water in a manner that delivers water to the surface without need for pumping. The water drains relying on gravity, with the destination lower than the source, an upland aquifer. Allows water to be transported long distances in hot dry climates without losing a large proportion of the source water to seepage and evaporation. Throughout Petra, the Nabataean engineers took advantage of every natural spring and every winter downpour to channel water where it was needed, they constructed aqueducts and piping systems that allowed water to flow across mountains, through gorges and into the temples and gardens of Petra's citizens. Walking through the Siq, one can spot the remains of channels that directed water to the city center, as well as durable retention dams that kept powerful flood waters at bay. On the island of Samos, the Tunnel of Eupalinos was built during the reign of Polycrates, it is considered an underground aqueduct and brought fresh water to Pythagoreion for a thousand years.

Roman aqueducts were built in all parts of the Roman Empire, from Germany to Africa, in the city of Rome, where they totalled over 415 kilometres. The aqueducts supplied fresh water to public baths and for drinking water, in large cities across the empire, set a standard of engineering, not surpassed for more than a thousand years. Bridges, built in stone with multiple arches, were a distinctive feature of Roman aqueducts and hence the term aqueduct is applied to a bridge for carrying water. Near the Peruvian town of Nazca, an ancient pre-Columbian system of aqueducts called Puquios were built and are still in use today, they were made of intricately placed stones, a construction material used by the Nazca culture. The time period in which they were constructed is still debated, but some evidence supports circa A. D. 540–552, in response to drought periods in the region. The Guayabo National Monument of Costa Rica, a park covering the largest archaeological site in the country, contains a system of aqueducts.

The complex network of uncovered and covered aqueducts still functions well. The aqueducts are constructed from rounded river stones, which are made of volcanic rock; the civilization that constructed the aqueduct system remains a mystery to archaeologists. When Europeans saw the Aztec capital Tenochtitlán, early in the 16th century, the city was watered by two aqueducts. One of these, Chapultepec Aqueduct, built circa 1420, was rebuilt by the Spanish three hundred years later. Tracing part of its path over now-gone Lake Texcoco, only a fragment remains in Mexico City today. Extensive usage of elaborate aqueducts have been found to have been used in ancient Sri Lanka; the best example is the Yoda Ela or Jaya Ganga, an 87 kilometres long water canal carrying excess water between two artificial reservoirs with a gradient of 10 to 20 cm per kilometer during the fifth century AD. However, the ancient engineering methods in calculating the exact elevation between the two reservoirs and the exact gradient of the canal to such fine precision had been lost with the fall of the civilization in 13th Century.

In modern times, the largest aqueducts of all have been built in the United States to supply the country's biggest cities. The Catskill Aqueduct carri


Xiafs was a file system for the Linux kernel, conceived and developed by Frank Xia and was based on the MINIX file system. Today it is obsolete and not in use, except in some historic installations. Linux used the MINIX file system, but it had a number of limitations. For example, the length of filenames was limited to 14 characters and the partition size was limited to 64 MB. To replace the MINIX file system, the extended file system was developed. However, ext retained some problems such as the lack of some date stamps. Two contenders for replacing ext were developed: ext2 and Xiafs; the two file systems were included in the standard kernel in December 1993. Ext2 and Xiafs had the same goal: To offer good performance, reasonable limitations, fixing the flaws of ext. Xiafs was more stable than ext2, but being a minimalistic modification of the MINIX file system, it was not well suited for future extension; the end result was that Xiafs changed little while ext2 evolved rapidly improving stability and performance, adding extensions.

Ext2, after some shakedown time became the standard file system of Linux. Since ext2 has developed into a mature and robust file system. Xiafs and the original ext were removed from Linux version 2.1.21, as they were no longer in use and were not maintained. Ext2, ext3, their successor ext4 are in the Linux kernel; as an exercise in computer history and as a file system tutorial, Xiafs was ported to modern Linux in 2013. Xiafs was less powerful and offered less functionality than ext2; the maximum size of a file was 64 MiB and the maximum size of a partition was 2 GiB. While this was an improvement over ext, it did not measure up to ext2. Xiafs used less disk space for its control structures and it had greater stability at that time. List of file systems Comparison of file systems A modern implementation of Xiafs

KidsAlive Charity

Kids Alive International is a Christian nonprofit organization founded to support child and community development. KAI's stated belief is that "every child deserves to live free from the bondage of hunger and exploitation." 1916 Official founding of the Home of Onesiphorus in Taian, China, by Rev. and Mrs. Leslie Anglin; the ministry began when the Anglins opened their home to widows in the province. 1921 Leslie Anglin made a trip to a severe famine area, to rescue children. 1937 The home had a yearly average of 95 % of whom graduated from the home's school. 1948 Dar El Awlad Boys' Home opened in Lebanon. 1953 Mission School established in Hong Kong for children of Chinese refuge families. 1962 Hong Kong missionaries started a Home for Boys with 15 boys. 1975 Civil War began in Lebanon, ending in 1992. KAI continued operating there during this time. 1983 Name changed to Kids Alive International. 1992 ANIJA School in Dominican Republic opened with first grade. Hauna Schools in Hauna Village, Papua New Guinea, affiliated with Kids Alive.

2000 Kids Alive began ministry in Africa, affiliating with the Mt. Kenya Boys’ Home, a year opened a children’s home in Lusaka, Zambia. 2004 Kids Alive Peru purchased land for the Care Center in the Manchay slum of Lima, with the goal of identifying and helping single mothers find work to support their kids. Kids Alive Schools KAI's schools vary depending on the country and community, but all aim to provide modern facilities and technology wherever possible, consistent teacher certification and ongoing training, up-to-date curriculum, stringent safety and security measures. KAI has schools in Dominican Republic, Haiti, Kenya, Papua New Guinea, Zambia. Care Centers and Medical Clinics KAI states that care centers “provide quality supervision, stimulating activities, healthy role models, nutritious meals and snacks, help with homework, counseling when necessary”. Medical clinics provide vaccinations, nutritional evaluations, basic first aid care, referrals to community medical facilities for advanced care.

Family-style Residential Homes KAI's stated goal is that a child should, if at all possible, remain with his or her natural family. In cases where children are abandoned or appear to be orphans, KAI can work with authorities to locate a child’s parents or other close family members; when a child has no home or is deemed unsafe in their own home because of abuse or exploitation concerns, KAI places them in small, family-style homes with dedicated caregivers.“Keeping Families Together” When a child has biological, extended, or adoptive family willing to provide care but unable to afford the basics, KAI offers assistance with nutrition, medical care, sometimes entrepreneurial help. Children are able to remain in a familiar setting with those who love them while receiving advantages their families cannot provide on their own. Lebanon 1948 Taiwan 1971 Dominican Republic 1989 Guatemala 1992 Peru 1992 Romania 1999 Kenya 2000 Zambia 2001 Haiti 2002 Sudan 2006 South Sudan 2011 Myanmar 2017 In the fiscal year 2016, Kids Alive reported $12,920,490.00 in revenue.

Of that amount, 85% went directly to programs and projects, 7.8% to administrative costs, 7% to fundraising. Kids Alive International has earned Charity Navigator’s 16th consecutive 4-star rating, a rating received by less than 1% of charities evaluated. According to Charity Navigator, this means that KAI outperforms most charities in the US for financial efficiency and transparency. On Charity Navigator’s “Top 10 Charities with the Most Consecutive 4-Star Ratings”, Kids Alive is the only one in its category with an overall score of 100. Kids Alive International Kids Alive Partner UK Kids Alive Taiwan KAI Guatemala Mission Work President Matt Parker - Growing as a Leader NWI Times - Kids Alive International Christian Alliance for Orphans - Kids Alive International Evangelical Council for Financial Accountability - Kids Alive International