Petroleum
Petroleum is a occurring, yellowish-black liquid found in geological formations beneath the Earth's surface. It is refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation using a fractionating column. It consists of occurring hydrocarbons of various molecular weights and may contain miscellaneous organic compounds; the name petroleum covers both occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms zooplankton and algae, are buried underneath sedimentary rock and subjected to both intense heat and pressure. Petroleum has been recovered by oil drilling. Drilling is carried out after studies of structural geology, sedimentary basin analysis, reservoir characterisation have been completed, it is refined and separated, most by distillation, into a large number of consumer products, from gasoline and kerosene to asphalt and chemical reagents used to make plastics and pharmaceuticals.
Petroleum is used in manufacturing a wide variety of materials, it is estimated that the world consumes about 95 million barrels each day. The use of petroleum as fuel is controversial due to its impact on global warming and ocean acidification. Fossil fuels, including petroleum, need to be phased out by the end of 21st century to avoid "severe and irreversable impacts for people and ecosystems", according to the UN's Intergovernmental Panel on Climate Change; the word petroleum comes from Medieval Latin petroleum, which comes from Latin petra', "rock", Latin oleum, "oil". The term was used in the treatise De Natura Fossilium, published in 1546 by the German mineralogist Georg Bauer known as Georgius Agricola. In the 19th century, the term petroleum was used to refer to mineral oils produced by distillation from mined organic solids such as cannel coal, refined oils produced from them. Petroleum, in one form or another, has been used since ancient times, is now important across society, including in economy and technology.
The rise in importance was due to the invention of the internal combustion engine, the rise in commercial aviation, the importance of petroleum to industrial organic chemistry the synthesis of plastics, solvents and pesticides. More than 4000 years ago, according to Herodotus and Diodorus Siculus, asphalt was used in the construction of the walls and towers of Babylon. Great quantities of it were found on the banks of the river Issus, one of the tributaries of the Euphrates. Ancient Persian tablets indicate the medicinal and lighting uses of petroleum in the upper levels of their society; the use of petroleum in ancient China dates back to more than 2000 years ago. In I Ching, one of the earliest Chinese writings cites that oil in its raw state, without refining, was first discovered and used in China in the first century BCE. In addition, the Chinese were the first to use petroleum as fuel as early as the fourth century BCE. By 347 AD, oil was produced from bamboo-drilled wells in China. Crude oil was distilled by Arabic chemists, with clear descriptions given in Arabic handbooks such as those of Muhammad ibn Zakarīya Rāzi.
The streets of Baghdad were paved with tar, derived from petroleum that became accessible from natural fields in the region. In the 9th century, oil fields were exploited in the area around Azerbaijan; these fields were described by the Arab geographer Abu al-Hasan'Alī al-Mas'ūdī in the 10th century, by Marco Polo in the 13th century, who described the output of those wells as hundreds of shiploads. Arab and Persian chemists distilled crude oil in order to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century, it has been present in Romania since the 13th century, being recorded as păcură. Early British explorers to Myanmar documented a flourishing oil extraction industry based in Yenangyaung that, in 1795, had hundreds of hand-dug wells under production. Pechelbronn is said to be the first European site where petroleum has been used; the still active Erdpechquelle, a spring where petroleum appears mixed with water has been used since 1498, notably for medical purposes.
Oil sands have been mined since the 18th century. In Wietze in lower Saxony, natural asphalt/bitumen has been explored since the 18th century. Both in Pechelbronn as in the coal industry dominated the petroleum technologies. Chemist James Young noticed a natural petroleum seepage in the Riddings colliery at Alfreton, Derbyshire from which he distilled a light thin oil suitable for use as lamp oil, at the same time obtaining a more viscous oil suitable for lubricating machinery. In 1848, Young set up a small business refining the crude oil. Young succeeded, by distilling cannel coal at a low heat, in creating a fluid resembling petroleum, which when treated in the same way as the seep oil gave similar products. Young found that by sl
Human Development Index
The Human Development Index is a statistic composite index of life expectancy and per capita income indicators, which are used to rank countries into four tiers of human development. A country scores a higher HDI when the lifespan is higher, the education level is higher, the GNI per capita is higher, it was developed by Pakistani economist Mahbub ul Haq, with help from Gustav Ranis of Yale University and Meghnad Desai of the London School of Economics, was further used to measure a country's development by the United Nations Development Program's Human Development Report Office. The 2010 Human Development Report introduced an Inequality-adjusted Human Development Index. While the simple HDI remains useful, it stated that "the IHDI is the actual level of human development", "the HDI can be viewed as an index of'potential' human development"; the index does not take into account several factors, such as the net wealth per capita or the relative quality of goods in a country. This situation tends to lower the ranking for some of the most advanced countries, such as the G7 members and others.
The index is based on the human development approach, developed by ul Haq framed in terms of whether people are able to "be" and "do" desirable things in life. Examples include—Being: well fed, healthy; the freedom of choice is central—someone choosing to be hungry is quite different from someone, hungry because they cannot afford to buy food, or because the country is in a famine. The origins of the HDI are found in the annual Human Development Reports produced by the Human Development Report Office of the United Nations Development Programme; these were devised and launched by Pakistani economist Mahbub ul Haq in 1990, had the explicit purpose "to shift the focus of development economics from national income accounting to people-centered policies". To produce the Human Development Reports, Mahbub ul Haq formed a group of development economists including Paul Streeten, Frances Stewart, Gustav Ranis, Keith Griffin, Sudhir Anand, Meghnad Desai. Nobel laureate Amartya Sen utilized Haq's work in his own work on human capabilities.
Haq believed that a simple composite measure of human development was needed to convince the public and politicians that they can and should evaluate development not only by economic advances but improvements in human well-being. Published on 4 November 2010, the 2010 Human Development Report calculated the HDI combining three dimensions: A long and healthy life: Life expectancy at birth Education index: Mean years of schooling and Expected years of schooling A decent standard of living: GNI per capita In its 2010 Human Development Report, the UNDP began using a new method of calculating the HDI; the following three indices are used: 1. Life Expectancy Index = LE − 20 85 − 20 LEI is 1 when Life expectancy at birth is 85 and 0 when Life expectancy at birth is 20.2. Education Index = MYSI + EYSI 2 2.1 Mean Years of Schooling Index = MYS 15 Fifteen is the projected maximum of this indicator for 2025. 2.2 Expected Years of Schooling Index = EYS 18 Eighteen is equivalent to achieving a master's degree in most countries.3.
Income Index = ln − ln ln − ln II is 1 when GNI per capita is $75,000 and 0 when GNI per capita is $100. The HDI is the geometric mean of the previous three normalized indices: HDI = LEI ⋅ EI ⋅ II 3. LE: Life expectancy at birth MYS: Mean years of schooling EYS: Expected years of schooling GNIpc: Gross national income at purchasing power parity per capita The HDI combined three dimensions last used in its 2009 Report: Life expectancy at birth, as an index of population health and longevity to HDI Knowledge and education, as measured by the adult literacy rate and the combined primary and tertiary gross enrollment ratio. Standard of living, as indicated by the natural logarithm of gross domestic product per capita at purchasing power parity; this methodology was used by the UNDP until their 2011 report. The formula defining the HDI is promulgated by the United Nations Development Programme. In general, to transform a raw variable, say x, into a unit-free index between 0 and 1 (which allo
Arable land
Arable land is, according to one definition, land capable of being ploughed and used to grow crops. In Britain, it was traditionally contrasted with pasturable land such as heaths which could be used for sheep-rearing but not farmland. A quite different kind of definition is used by various agencies concerned with agriculture. In providing statistics on arable land, the FAO and the World Bank use the definition offered in the glossary accompanying FAOSTAT: "Arable land is the land under temporary agricultural crops, temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporarily fallow; the abandoned land resulting from shifting cultivation is not included in this category. Data for ‘Arable land’ are not meant to indicate the amount of land, cultivable." A more concise definition appearing in the Eurostat glossary refers to actual, rather than potential use: "land worked generally under a system of crop rotation." Cultivation of the land is an important process to make land arable by loosening and tilling of the soil.
According to Food and Agriculture Organization of the United Nations the world's arable land amounted to 1,407 M ha, out of a total 4,924 M ha land used for agriculture, as for year 2013. Agricultural land, not arable according to the FAO definition above includes: Permanent crop – land that produces crops from woody vegetation, e.g. orchardland, coffee plantations, rubber plantations, land producing nut trees. Other non-arable land includes land, not suitable for any agricultural use. Land, not arable, in the sense of lacking capability or suitability for cultivation for crop production, has one or more limitations e.g. lack of sufficient fresh water for irrigation, steepness, adverse climate, excessive wetness with impracticality of drainage, excessive salts, among others. Although such limitations may preclude cultivation, some will in some cases preclude any agricultural use, large areas unsuitable for cultivation are agriculturally productive. For example, US NRCS statistics indicate that about 59 percent of US non-federal pasture and unforested rangeland is unsuitable for cultivation, yet such land has value for grazing of livestock.
In British Columbia, Canada, 41 percent of the provincial Agricultural Land Reserve area is unsuitable for production of cultivated crops, but is suitable for uncultivated production of forage usable by grazing livestock. Similar examples can be found in many rangeland areas elsewhere. Land incapable of being cultivated for production of crops can sometimes be converted to arable land. New arable land makes more food, can reduce starvation; this outcome makes a country more self-sufficient and politically independent, because food importation is reduced. Making non-arable land arable involves digging new irrigation canals and new wells, desalination plants, planting trees for shade in the desert, fertilizer, nitrogen fertilizer, reverse osmosis water processors, PET film insulation or other insulation against heat and cold, digging ditches and hills for protection against the wind, greenhouses with internal light and heat for protection against the cold outside and to provide light in cloudy areas.
This process is extremely expensive. An alternative is the Seawater Greenhouse which desalinates water through evaporation and condensation using solar energy as the only energy input; this technology is optimized to grow crops on desert land close to the sea. Some examples of infertile non-arable land being turned into fertile arable land are: Aran Islands: These islands off the west coast of Ireland, were unsuitable for arable farming because they were too rocky; the people covered the islands with a shallow layer of sand from the ocean. Today, crops are grown there though, the islands are still considered non-arable. Israel: The construction of desalination plants along Israel's coast allowed agriculture in some areas that were desert; the desalination plants, which remove the salt from ocean water, have created a new source of water for farming and washing. Slash and burn agriculture uses nutrients in wood ash. Terra preta, fertile tropical soils created by adding charcoal; some examples of fertile arable land being turned into infertile land are: Droughts like the'dust bowl' of the Great Depression in the U.
S. turned farmland into desert. Rainforest deforestation: The fertile tropical forests are converted into infertile desert land. For example, Madagascar's central highland plateau has become totally barren, as a result of slash-and-burn deforestation, an element of s
Maize
Maize known as corn, is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits. Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. However, little of this maize is consumed directly by humans: most is used for corn ethanol, animal feed and other maize products, such as corn starch and corn syrup; the six major types of maize are dent corn, flint corn, pod corn, flour corn, sweet corn. Maize is the most grown grain crop throughout the Americas, with 361 million metric tons grown in the United States in 2014. 40% of the crop—130 million tons—is used for corn ethanol. Genetically modified maize made up 85% of the maize planted in the United States in 2009. Sugar-rich varieties called sweet corn are grown for human consumption as kernels, while field corn varieties are used for animal feed, various corn-based human food uses, as chemical feedstocks.
Maize is used in making ethanol and other biofuels. Most historians believe. Recent research in the early 21st century has modified this view somewhat. An influential 2002 study by Matsuoka et al. has demonstrated that, rather than the multiple independent domestications model, all maize arose from a single domestication in southern Mexico about 9,000 years ago. The study demonstrated that the oldest surviving maize types are those of the Mexican highlands. Maize spread from this region over the Americas along two major paths; this is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands. Archaeologist Dolores Piperno has said: A large corpus of data indicates that it was dispersed into lower Central America by 7600 BP and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP. Since even earlier dates have been published. According to a genetic study by Embrapa, corn cultivation was introduced in South America from Mexico, in two great waves: the first, more than 6000 years ago, spread through the Andes.
Evidence of cultivation in Peru has been found dating to about 6700 years ago. The second wave, about 2000 years ago, through the lowlands of South America. Before domestication, maize plants grew only small, 25 millimetres long corn cobs, only one per plant. In Spielvogel's view, many centuries of artificial selection by the indigenous people of the Americas resulted in the development of maize plants capable of growing several cobs per plant, which were several centimetres/inches long each; the Olmec and Maya cultivated maize in numerous varieties throughout Mesoamerica. It was believed. Research of the 21st century has established earlier dates; the region developed a trade network based on surplus and varieties of maize crops. Mapuches of south-central Chile cultivated maize along with quinoa and potatoes in Pre-Hispanic times, however potato was the staple food of most Mapuches, "specially in the southern and coastal territories where maize did not reach maturity". Before the expansion of the Inca Empire maize was traded and transported as far south as 40°19' S in Melinquina, Lácar Department.
In that location maize remains were found inside pottery dated to 730 ±80 BP and 920 ±60 BP. This maize was brought across the Andes from Chile; the presence of maize in Guaitecas Archipelago, which constitute southernmost outspost of Pre-Hispanic agriculture, is reported by early Spanish explorers. However the Spanish may have misidentified the plant. After the arrival of Europeans in 1492, Spanish settlers consumed maize and explorers and traders carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in Christian belief only wheat could undergo transubstantiation and be transformed into the body of Christ; some Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities."
Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate. Maize spread to the rest of the world because of its ability to grow in diverse climates, it was cultivated in Spain just a few decades after Columbus's voyages and spread to Italy, West Africa and elsewhere. The word maize derives from the Spanish form of the indigenous Taíno word for mahiz, it is known by other names around the world. The word "corn" outside North America and New Zealand refers to any cereal crop, its meaning understood to vary geographically to refer to the local staple. In the United Stat
Niger Delta
The Niger Delta is the delta of the Niger River sitting directly on the Gulf of Guinea on the Atlantic Ocean in Nigeria. It is considered to be located within nine coastal southern Nigerian states, which include: all six states from the South South geopolitical zone, one state from South West geopolitical zone and two states from South East geopolitical zone. Of all the states that the region covers, only Cross River is not an oil-producing state; the Niger Delta is a densely populated region sometimes called the Oil Rivers because it was once a major producer of palm oil. The area was the British Oil Rivers Protectorate from 1885 until 1893, when it was expanded and became the Niger Coast Protectorate; the delta is a petroleum-rich region and has been the center of international controversy over pollution. The Niger Delta, as now defined by the Nigerian government, extends over about 70,000 km2 and makes up 7.5% of Nigeria's land mass. And cartographically, it consists of present-day Bayelsa and Rivers States.
In 2000, Obasanjo's regime included Abia, Akwa-Ibom, Cross River State, Edo and Ondo States in the region. Some 31 million people of more than 40 ethnic groups including the Bini, Esan, Igbo, Yoruba, Ijaw, Abua/Odual, Isoko, Ukwuani, Kalabari and Ogoni, are among the inhabitants of the political Niger Delta, speaking about 250 different dialects; the Niger Delta, the South South geopolitical zone are two different entities. The Niger Delta separates the Bight of Benin from the Bight of Bonny within the larger Gulf of Guinea; the area was the British Oil Rivers Protectorate from 1885 until 1893, when it was expanded and became the Niger Coast Protectorate. The core Niger Delta became a part of the eastern region of Nigeria, which came into being in 1951; the majority of the people were those from the colonial Calabar and Ogoja divisions, the present-day Ogoja, Ibibio, Efik and Ogoni peoples. The National Council of Nigeria and Cameroon was the ruling political party of the region; the NCNC became the National Convention of Nigerian Citizens, after western Cameroon decided to separate from Nigeria.
The ruling party of eastern Nigeria did not seek to preclude the separation and encouraged it. The Eastern Region had the third and fifth largest indigenous ethnic groups in the country including Igbo, Efik-Ibibio and Ijaw. In 1953, the old eastern region had a major crisis due to the expulsion of professor Eyo Ita from office by the majority Igbo tribe of the old eastern region. Ita, an Efik man from Calabar, was one of the pioneer nationalists for Nigerian independence; the minorities in the region, the Ibibio, Efik and Ogoja, were situated along the southeastern coast and in the delta region and demanded a state of their own, the Calabar-Ogoja-Rivers state. The struggle for the creation of the COR state continued and was a major issue concerning the status of minorities in Nigeria during debates in Europe on Nigerian independence; as a result of this crisis, Professor Eyo Ita left the NCNC to form a new political party called the National Independence Party, one of the five Nigerian political parties represented at the conferences on Nigerian Constitution and Independence.
In 1961, another major crisis occurred when the eastern region of Nigeria allowed present-day Southwestern Cameroon to separate from Nigeria through a plebiscite while the leadership of the Northern Region took the necessary steps to keep Northwestern Cameroon in Nigeria, in present-day Adamawa and Taraba states. The aftermath of the 1961 plebiscite has led to a dispute between Cameroon and Nigeria over the small territory of Bakassi. A new phase of the struggle saw the declaration of an Independent Niger Delta Republic by Isaac Adaka Boro during Nigerian president Ironsi's administration, just before the Nigerian Civil War. Just before the Nigerian civil war, Southeastern State of Nigeria was created, which had the colonial Calabar division, colonial Ogoja division. Rivers State was created. Southeastern state and River state became two states for the minorities of the old eastern region, the majority Igbo of the old eastern region had a state called East Central state. Southeastern state was renamed Cross River state and was split into Cross River state and Akwa Ibom state.
Rivers state was divided into Rivers state and Bayelsa State. The people of the eastern region suffered and sustained many deaths during 1967–1970 Nigerian Civil War known as the Biafran War, in which the eastern region declared an independent state named Biafra, defeated, thereby preserving the sovereignty and indivisibility of the Nigerian state, which led to the loss of many souls. During the next phase of resistance in the Niger Delta, local communities demanded environmental and social justice from the federal government, with Ken Saro Wiwa and the Ogoni tribe as the lead figures for this phase of the struggle. Cohesive oil protests became most pronounced in 1990 with the publication of the Ogoni Bill of Rights; the indigents protested against the lack of economic development, e.g. schools, good roads, hospitals, in the region, despite all the oil wealth created. They complained about environmental pollution and destruction of their land and rivers by foreign oil companies. Ken Saro Wiwa and nine other oil activists from Movement for the Survival of the Ogoni People
Ude Oko Chukwu
Rt. Hon. Sir, Ude Oko Chukwu is a Nigerian accountant and politician who serves as the Deputy Governor of Abia State after he was elected into office in 2015 under the platform of the People's Democratic Party. Prior to his swearing-in as Deputy Governor, he had served as the Speaker of the 5th Abia State House of Assembly. Ude was born on 1 January 1962 into a Catholic family in Etitiama Nkporo, a town in the Ohafia local government area of Abia State, he completed his basic education at Ndi Elu Primary School and his secondary education at Nkporo Secondary School, Nkporo in 1970 and 1982 respectively. Ude served as an accountant for SMACS Computers and General Manager, CONTECH Ventures Ltd. between 1988 and 1996 before he went on to establish Chukwu Ude Oko Chukwu and Co. in 2001. He is a fellow of the Institute of Chartered Accountants of Nigeria, he became politically active in 2001 and in 2003 won a seat in the Abia State House of Assembly, representing Ohafia North Constituency. He was appointed Speaker of the 5th Abia State House of Assembly by Theodore Orji in 2011, a position he held until his election as Deputy Governor of Abia State
Cement
A cement is a binder, a substance used for construction that sets and adheres to other materials to bind them together. Cement is used on its own, but rather to bind sand and gravel together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Cement is the most used material in existence and is only behind water as the planet's most-consumed resource. Cements used in construction are inorganic lime or calcium silicate based, can be characterized as either hydraulic or non-hydraulic, depending on the ability of the cement to set in the presence of water. Non-hydraulic cement does not set under water. Rather, it sets as it reacts with carbon dioxide in the air, it is resistant to attack by chemicals after setting. Hydraulic cements set and become adhesive due to a chemical reaction between the dry ingredients and water; the chemical reaction results in mineral hydrates that are not water-soluble and so are quite durable in water and safe from chemical attack.
This allows setting in wet conditions or under water and further protects the hardened material from chemical attack. The chemical process for hydraulic cement found by ancient Romans used volcanic ash with added lime; the word "cement" can be traced back to the Roman term opus caementicium, used to describe masonry resembling modern concrete, made from crushed rock with burnt lime as binder. The volcanic ash and pulverized brick supplements that were added to the burnt lime, to obtain a hydraulic binder, were referred to as cementum, cimentum, cäment, cement. In modern times, organic polymers are sometimes used as cements in concrete. Non-hydraulic cement, such as slaked lime, hardens by carbonation in the presence of carbon dioxide, present in the air. First calcium oxide is produced from calcium carbonate by calcination at temperatures above 825 °C for about 10 hours at atmospheric pressure: CaCO3 → CaO + CO2The calcium oxide is spent mixing it with water to make slaked lime: CaO + H2O → Ca2Once the excess water is evaporated, the carbonation starts: Ca2 + CO2 → CaCO3 + H2OThis reaction takes time, because the partial pressure of carbon dioxide in the air is low.
The carbonation reaction requires that the dry cement be exposed to air, so the slaked lime is a non-hydraulic cement and cannot be used under water. This process is called the lime cycle. Conversely, hydraulic cement hardens by hydration. Hydraulic cements are made of a mixture of silicates and oxides, the four main components being: Belite; the silicates are responsible for the cement's mechanical properties—the tricalcium aluminate and brownmillerite are essential for formation of the liquid phase during the kiln sintering. The chemistry of these reactions is not clear and is still the object of research; the earliest known occurrence of cement is from twelve million years ago. A deposit of cement was formed after an occurrence of oil shale located adjacent to a bed of limestone burned due to natural causes; these ancient deposits were investigated in the 1970s. Cement, chemically speaking, is a product that includes lime as the primary curing ingredient, but is far from the first material used for cementation.
The Babylonians and Assyrians used bitumen to bind together burnt alabaster slabs. In Egypt stone blocks were cemented together with a mortar made of sand and burnt gypsum, which contained calcium carbonate. Lime was used by the ancient Greeks. There is evidence that the Minoans of Crete used crushed potshards as an artificial pozzolan for hydraulic cement. Nobody knows who first discovered that a combination of hydrated non-hydraulic lime and a pozzolan produces a hydraulic mixture —but such concrete was used by the Ancient Macedonians, three centuries on a large scale by Roman engineers. There is... a kind of powder. It is found in the neighborhood of Baiae and in the country belonging to the towns round about Mt. Vesuvius; this substance when mixed with lime and rubble not only lends strength to buildings of other kinds, but when piers of it are constructed in the sea, they set hard under water. The Greeks used volcanic tuff from the island of Thera as their pozzolan and the Romans used crushed volcanic ash with lime.
This mixture could set under water. The material was called pozzolana from the town of Pozzuoli, west of Naples where volcanic ash was extracted. In the absence of pozzolanic ash, the Romans used powdered brick or pottery as a substitute and they may have used crushed tiles for this purpose before discovering natural sources near Rome; the huge dome of the Pantheon in Rome and the massive Baths of Caracalla are examples of ancient structures made from these concretes, many of which still stand. The vast system of Roman aqueducts made extensive use of hydraulic cement. Roman concrete was used on the outside of buildings; the normal technique was to use brick facing material as the formwork for an infill of mortar mixed with an aggregate of broken pieces of stone, potsherds, recycled chunks of concrete, or other building ru
Nigeria
