Misplaced Pages

#109890

164-490: The name Tsumeb is generally pronounced "SOO-meb". The name is not a derivative of German , Afrikaans , or English . It has been suggested that it comes from Nama and means either "Place of the moss" or "Place of the frog". Perhaps this old name had something to do with the huge natural hill of green, oxidized copper ore that existed there before it was mined out. The town was founded in 1905 by German colonial power and celebrated its 100th year of existence in 2005. Tsumeb

328-557: A concrete sleeper factory. Just a few kilometres North of Tsumeb, the construction of the 40 MW Otjikoto Biomass Power Station began in 2024, with an expected completion in 2027. Every year the Tsumeb Municipality organises the Tsumeb Copper Festival. More than 200 small and medium enterprises (SMEs) and bigger exhibitors showcase their products and services at the annual fair. The festival takes place annually during

492-460: A de facto official language of Namibia after the end of German colonial rule alongside English and Afrikaans , and had de jure co-official status from 1984 until its independence from South Africa in 1990. However, the Namibian government perceived Afrikaans and German as symbols of apartheid and colonialism, and decided English would be the sole official language upon independence, stating that it

656-406: A diver propulsion vehicle , or a sled pulled from the surface. Other equipment needed for scuba diving includes a mask to improve underwater vision, exposure protection by means of a diving suit , ballast weights to overcome excess buoyancy, equipment to control buoyancy , and equipment related to the specific circumstances and purpose of the dive, which may include a snorkel when swimming on

820-402: A second language , and 75–100   million as a foreign language . This would imply the existence of approximately 175–220   million German speakers worldwide. German sociolinguist Ulrich Ammon estimated a number of 289 million German foreign language speakers without clarifying the criteria by which he classified a speaker. As of 2012 , about 90   million people, or 16% of

984-587: A "commonly used" language and the Pan South African Language Board is obligated to promote and ensure respect for it. Cameroon was also a colony of the German Empire from the same period (1884 to 1916). However, German was replaced by French and English, the languages of the two successor colonial powers, after its loss in World War I . Nevertheless, since the 21st century, German has become

1148-493: A "single-hose" open-circuit 2-stage demand regulator, connected to a single back-mounted high-pressure gas cylinder, with the first stage connected to the cylinder valve and the second stage at the mouthpiece. This arrangement differs from Émile Gagnan's and Jacques Cousteau 's original 1942 "twin-hose" design, known as the Aqua-lung, in which the cylinder pressure was reduced to ambient pressure in one or two stages which were all in

1312-402: A "sled", an unpowered device towed behind a surface vessel that conserves the diver's energy and allows more distance to be covered for a given air consumption and bottom time. The depth is usually controlled by the diver by using diving planes or by tilting the whole sled. Some sleds are faired to reduce drag on the diver. To dive safely, divers must control their rate of descent and ascent in

1476-431: A backplate, and the cylinders rested directly against the diver's back. Early scuba divers dived without a buoyancy aid. In an emergency they had to jettison their weights. In the 1960s adjustable buoyancy life jackets (ABLJ) became available, which can be used to compensate for loss of buoyancy at depth due to compression of the neoprene wetsuit and as a lifejacket that will hold an unconscious diver face-upwards at

1640-404: A capacity of 1,500. The main road leads north, to Ondangwa and onwards to Oshakati and Angola . To the north-east a newly constructed Bituminous Road towards Tsintsabis leads to Katwitwi Border Post and Angola . To the east, through Grootfontein , the road leads towards Rundu and Katima Mulilo and to the south, through Otavi to Otjiwarongo and Windhoek . Tsumeb is connected to

1804-422: A frame and skirt, which are opaque or translucent, therefore the total field-of-view is significantly reduced and eye-hand coordination must be adjusted. Divers who need corrective lenses to see clearly outside the water would normally need the same prescription while wearing a mask. Generic corrective lenses are available off the shelf for some two-window masks, and custom lenses can be bonded onto masks that have

SECTION 10

#1732859020110

1968-556: A greater need for regularity in written conventions. While the major changes of the MHG period were socio-cultural, High German was still undergoing significant linguistic changes in syntax, phonetics, and morphology as well (e.g. diphthongization of certain vowel sounds: hus (OHG & MHG "house") → haus (regionally in later MHG)→ Haus (NHG), and weakening of unstressed short vowels to schwa [ə]: taga (OHG "days")→ tage (MHG)). A great wealth of texts survives from

2132-456: A higher oxygen content, known as enriched air or nitrox , has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives. Open-circuit scuba systems discharge the breathing gas into the environment as it is exhaled, and consist of one or more diving cylinders containing breathing gas at high pressure which

2296-467: A kilometre deep and the water was collected and pumped as far as the capital, Windhoek . The mine has since been opened up again by a group of local entrepreneurs ("Ongopolo Mining"). A fair amount of oxidized ore remains to be recovered in the old upper levels of the mine. It is highly unlikely, though, that the deepest levels will ever be reopened. The other notable feature of the town is the metal smelter, previously owned by Namibia Custom Smelters, which

2460-402: A line held by the diver indicates the position of the diver to the surface personnel. This may be an inflatable marker deployed by the diver at the end of the dive, or a sealed float, towed for the whole dive. A surface marker also allows easy and accurate control of ascent rate and stop depth for safer decompression. Various surface detection aids may be carried to help surface personnel spot

2624-448: A low-pressure hose from the first stage, delivers the breathing gas at ambient pressure to the diver's mouth. The exhaled gases are exhausted directly to the environment as waste through a non-return valve on the second stage housing. The first stage typically has at least one outlet port delivering gas at full tank pressure which is connected to the diver's submersible pressure gauge or dive computer, to show how much breathing gas remains in

2788-408: A mask than normal-sighted people. Diving masks and helmets solve this problem by providing an air space in front of the diver's eyes. The refraction error created by the water is mostly corrected as the light travels from water to air through a flat lens, except that objects appear approximately 34% bigger and 25% closer in water than they actually are. The faceplate of the mask is supported by

2952-504: A more conservative approach for a SCR than for a CCR, but decompression computers with a real-time oxygen partial pressure input can optimise decompression for these systems. Because rebreathers produce very few bubbles, they do not disturb marine life or make a diver's presence known at the surface; this is useful for underwater photography, and for covert work. For some diving, gas mixtures other than normal atmospheric air (21% oxygen, 78% nitrogen , 1% trace gases) can be used, so long as

3116-453: A native tongue today, mostly descendants of German colonial settlers . The period of German colonialism in Namibia also led to the evolution of a Standard German-based pidgin language called " Namibian Black German ", which became a second language for parts of the indigenous population. Although it is nearly extinct today, some older Namibians still have some knowledge of it. German remained

3280-413: A number of applications, including scientific, military and public safety roles, but most commercial diving uses surface-supplied diving equipment when this is practicable. Scuba divers engaged in armed forces covert operations may be referred to as frogmen , combat divers or attack swimmers. A scuba diver primarily moves underwater using fins worn on the feet, but external propulsion can be provided by

3444-679: A popular foreign language among pupils and students, with 300,000 people learning or speaking German in Cameroon in 2010 and over 230,000 in 2020. Today Cameroon is one of the African countries outside Namibia with the highest number of people learning German. In the United States, German is the fifth most spoken language in terms of native and second language speakers after English, Spanish , French , and Chinese (with figures for Cantonese and Mandarin combined), with over 1 million total speakers. In

SECTION 20

#1732859020110

3608-423: A result, divers can stay down longer or require less time to decompress. A semi-closed circuit rebreather injects a constant mass flow of a fixed breathing gas mixture into the breathing loop, or replaces a specific percentage of the respired volume, so the partial pressure of oxygen at any time during the dive depends on the diver's oxygen consumption and/or breathing rate. Planning decompression requirements requires

3772-475: A result, the surviving texts are written in highly disparate regional dialects and exhibit significant Latin influence, particularly in vocabulary. At this point monasteries, where most written works were produced, were dominated by Latin, and German saw only occasional use in official and ecclesiastical writing. While there is no complete agreement over the dates of the Middle High German (MHG) period, it

3936-524: A safe continuous maximum, which reduces the inert gas (nitrogen and/or helium) partial pressure in the breathing loop. Minimising the inert gas loading of the diver's tissues for a given dive profile reduces the decompression obligation. This requires continuous monitoring of actual partial pressures with time and for maximum effectiveness requires real-time computer processing by the diver's decompression computer. Decompression can be much reduced compared to fixed ratio gas mixes used in other scuba systems and, as

4100-401: A shorter surface interval between dives. The increased partial pressure of oxygen due to the higher oxygen content of nitrox increases the risk of oxygen toxicity, which becomes unacceptable below the maximum operating depth of the mixture. To displace nitrogen without the increased oxygen concentration, other diluent gases can be used, usually helium , when the resultant three gas mixture

4264-478: A single front window or two windows. As a diver descends, they must periodically exhale through their nose to equalise the internal pressure of the mask with that of the surrounding water. Swimming goggles are not suitable for diving because they only cover the eyes and thus do not allow for equalisation. Failure to equalise the pressure inside the mask may lead to a form of barotrauma known as mask squeeze. Masks tend to fog when warm humid exhaled air condenses on

4428-425: A sulfide deposit rich in many metals. A non-arid environment plentiful in oxygen-rich groundwater contributed to leaching and re-deposition of these elements as new minerals, sometimes in crystalline formations. There are rare secondary minerals of Pb, Cu, Zn, As, Sb and, reflecting the ore deposit chemistry, Ge, Ga and Cd as well. Minerals first described from Tsumeb include, according to Mindat.org : Tsumeb

4592-509: A tropical coral reef ). The removal ("ditching" or "shedding") of diver weighting systems can be used to reduce the diver's weight and cause a buoyant ascent in an emergency. Diving suits made of compressible materials decrease in volume as the diver descends, and expand again as the diver ascends, causing buoyancy changes. Diving in different environments also necessitates adjustments in the amount of weight carried to achieve neutral buoyancy. The diver can inject air into dry suits to counteract

4756-403: A tube below 3 feet (0.9 m) under the water. Most recreational scuba diving is done using a half mask which covers the diver's eyes and nose, and a mouthpiece to supply the breathing gas from the demand valve or rebreather. Inhaling from a mouthpiece becomes second nature very quickly. The other common arrangement is a full-face mask which covers the eyes, nose and mouth, and often allows

4920-580: Is a recognized minority language in the following countries: In France, the High German varieties of Alsatian and Moselle Franconian are identified as " regional languages ", but the European Charter for Regional or Minority Languages of 1998 has not yet been ratified by the government. Namibia also was a colony of the German Empire, from 1884 to 1915. About 30,000 people still speak German as

5084-413: Is a risk of getting the anti-fog agent in the eyes. Water attenuates light by selective absorption. Pure water preferentially absorbs red light, and to a lesser extent, yellow and green, so the colour that is least absorbed is blue light. Dissolved materials may also selectively absorb colour in addition to the absorption by the water itself. In other words, as a diver goes deeper on a dive, more colour

Tsumeb - Misplaced Pages Continue

5248-437: Is absorbed by the water, and in clean water the colour becomes blue with depth. Colour vision is also affected by the turbidity of the water which tends to reduce contrast. Artificial light is useful to provide light in the darkness, to restore contrast at close range, and to restore natural colour lost to absorption. Dive lights can also attract fish and a variety of other sea creatures. Protection from heat loss in cold water

5412-502: Is affected by woody plant encroachment . The soil around Tsumeb varies in quality from very fertile red loam through black turf to chalky clay and loam. The district is thus suitable for intensified farming and crop production. There is an abundance of ground water and regular rainfall in the summer months. Irrigation makes the area even more productive . Farmers in the area grow citrus fruits with much success. The main crops grown are maize , sorghum and sunflowers . Cattle farming

5576-486: Is also commonly referred to as the scuba set. As one descends, in addition to the normal atmospheric pressure at the surface, the water exerts increasing hydrostatic pressure of approximately 1 bar (14.7 pounds per square inch) for every 10 m (33 feet) of depth. The pressure of the inhaled breath must balance the surrounding or ambient pressure to allow controlled inflation of the lungs. It becomes virtually impossible to breathe air at normal atmospheric pressure through

5740-596: Is also notable for its broad spectrum of dialects , with many varieties existing in Europe and other parts of the world. Some of these non-standard varieties have become recognized and protected by regional or national governments. Since 2004, heads of state of the German-speaking countries have met every year, and the Council for German Orthography has been the main international body regulating German orthography . German

5904-401: Is also widespread. Ohorongo Cement was established in 2007. The plant is situated between Tsumeb and Otavi on Farm Sargberg approximately 45 km south of Tsumeb. The plant has a production capacity of 650000 tonnes per annum, almost double the demand of the Namibian domestic market. It is owned by Schwenk KG . Limestone reserves appear to be adequate for approximately 300 years. Tsumeb has

6068-546: Is an Indo-European language that belongs to the West Germanic group of the Germanic languages . The Germanic languages are traditionally subdivided into three branches: North Germanic , East Germanic , and West Germanic . The first of these branches survives in modern Danish , Swedish , Norwegian , Faroese , and Icelandic , all of which are descended from Old Norse . The East Germanic languages are now extinct, and Gothic

6232-415: Is an acronym for " Self-Contained Underwater Breathing Apparatus " and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas , usually compressed air , affording them greater independence and movement than surface-supplied divers , and more time underwater than free divers. Although the use of compressed air is common, a gas blend with

6396-544: Is below 15 °C (60 °F) or for extended immersion in water above 15 °C (60 °F), where a wetsuit user would get cold, and with an integral helmet, boots, and gloves for personal protection when diving in contaminated water. Dry suits are designed to prevent water from entering. This generally allows better insulation making them more suitable for use in cold water. They can be uncomfortably hot in warm or hot air, and are typically more expensive and more complex to don. For divers, they add some degree of complexity as

6560-467: Is called trimix , and when the nitrogen is fully substituted by helium, heliox . For dives requiring long decompression stops, divers may carry cylinders containing different gas mixtures for the various phases of the dive, typically designated as travel, bottom, and decompression gases. These different gas mixtures may be used to extend bottom time, reduce inert gas narcotic effects, and reduce decompression times. Back gas refers to any gas carried on

6724-472: Is called the "German Sprachraum ". German is the official language of the following countries: German is a co-official language of the following countries: Although expulsions and (forced) assimilation after the two World wars greatly diminished them, minority communities of mostly bilingual German native speakers exist in areas both adjacent to and detached from the Sprachraum. Within Europe, German

Tsumeb - Misplaced Pages Continue

6888-430: Is complicated by the existence of several varieties whose status as separate "languages" or "dialects" is disputed for political and linguistic reasons, including quantitatively strong varieties like certain forms of Alemannic and Low German . With the inclusion or exclusion of certain varieties, it is estimated that approximately 90–95 million people speak German as a first language , 10–25   million speak it as

7052-400: Is facilitated by ascending on a line with a buoy at the top. The diver can remain marginally negative and easily maintain depth by holding onto the line. A shotline or decompression buoy are commonly used for this purpose. Precise and reliable depth control are particularly valuable when the diver has a large decompression obligation, as it allows the theoretically most efficient decompression at

7216-520: Is generally seen as ending when the 1346–53 Black Death decimated Europe's population. Modern High German begins with the Early New High German (ENHG) period, which Wilhelm Scherer dates 1350–1650, terminating with the end of the Thirty Years' War . This period saw the further displacement of Latin by German as the primary language of courtly proceedings and, increasingly, of literature in

7380-595: Is generally seen as lasting from 1050 to 1350. This was a period of significant expansion of the geographical territory occupied by Germanic tribes, and consequently of the number of German speakers. Whereas during the Old High German period the Germanic tribes extended only as far east as the Elbe and Saale rivers, the MHG period saw a number of these tribes expanding beyond this eastern boundary into Slavic territory (known as

7544-421: Is greater per unit of depth near the surface. Minimising the volume of gas required in the buoyancy compensator will minimise the buoyancy fluctuations with changes in depth. This can be achieved by accurate selection of ballast weight, which should be the minimum to allow neutral buoyancy with depleted gas supplies at the end of the dive unless there is an operational requirement for greater negative buoyancy during

7708-641: Is home to a number of primary and secondary schools as well as an Adult Education Center, which resorts under the Ministry of Education and Culture . 19°15′S 17°42′E  /  19.250°S 17.700°E  / -19.250; 17.700 German language German (German: Deutsch , pronounced [dɔʏtʃ] ) is a West Germanic language in the Indo-European language family , mainly spoken in Western and Central Europe . It

7872-533: Is known as a buoyancy control device or buoyancy compensator. A backplate and wing is an alternative configuration of a scuba harness with a buoyancy compensation bladder known as a "wing" mounted behind the diver, sandwiched between the backplate and the cylinder or cylinders. Unlike stabilizer jackets, the backplate and wing is a modular system, in that it consists of separable components. This arrangement became popular with cave divers making long or deep dives, who needed to carry several extra cylinders, as it clears

8036-559: Is less closely related to languages based on Low Franconian dialects (e.g., Dutch and Afrikaans), Low German or Low Saxon dialects (spoken in northern Germany and southern Denmark ), neither of which underwent the High German consonant shift. As has been noted, the former of these dialect types is Istvaeonic and the latter Ingvaeonic, whereas the High German dialects are all Irminonic; the differences between these languages and standard German are therefore considerable. Also related to German are

8200-427: Is located at the "wrong end" of Tsumeb railway station , leaving it a dead end, though a second triangle is provided for through trains to bypass the station. Tsumeb Airport is an airstrip east of town. Tsumeb is governed by a municipal council that has seven seats. Nico Kaiyamo is one of the well-known and established local politicians. In the 2010 local authority election , a total of 3,120 votes were cast in

8364-483: Is not possible to use a weight to sound them. Otjikoto, which has poor visibility (owing to pollution from agricultural fertilizers used nearby), is at least 60 m deep. The water in Guinas is completely clear and well over 100 m deep. Divers who have performed bounce-dives in Guinas to 80 m (strictly speaking, beyond the safe depth for such dives, especially given the altitude of the lake above sea level) have reported that there

SECTION 50

#1732859020110

8528-475: Is notable for the huge mineralized pipe that led to its foundation. The origin of the pipe has been hotly debated. The pipe penetrates more or less vertically through the Precambrian Otavi dolomite for at least 1,300 m. One possibility is that the pipe was actually a gigantic ancient cave system and that the rock filling it is sand that seeped in from above. If the pipe is volcanic, as some have suggested, then

8692-621: Is now commonly referred to as technical diving for decades. One reasonably widely held definition is that any dive in which at some point of the planned profile it is not physically possible or physiologically acceptable to make a direct and uninterrupted vertical ascent to surface air is a technical dive. The equipment often involves breathing gases other than air or standard nitrox mixtures, multiple gas sources, and different equipment configurations. Over time, some equipment and techniques developed for technical diving have become more widely accepted for recreational diving. Oxygen toxicity limits

8856-435: Is one of the major languages of the world . German is the second-most widely spoken Germanic language , after English, both as a first and as a second language . German is also widely taught as a foreign language , especially in continental Europe (where it is the third most taught foreign language after English and French), and in the United States. Overall, German is the fourth most commonly learned second language, and

9020-587: Is one of the three biggest newspapers in Namibia and the only German-language daily in Africa. An estimated 12,000 people speak German or a German variety as a first language in South Africa, mostly originating from different waves of immigration during the 19th and 20th centuries. One of the largest communities consists of the speakers of "Nataler Deutsch", a variety of Low German concentrated in and around Wartburg . The South African constitution identifies German as

9184-401: Is partly derived from Latin and Greek , along with fewer words borrowed from French and Modern English . English, however, is the main source of more recent loanwords . German is a pluricentric language ; the three standardized variants are German , Austrian , and Swiss Standard German . Standard German is sometimes called High German , which refers to its regional origin. German

9348-430: Is recovered; this has advantages for research, military, photography, and other applications. Rebreathers are more complex and more expensive than open-circuit scuba, and special training and correct maintenance are required for them to be safely used, due to the larger variety of potential failure modes. In a closed-circuit rebreather the oxygen partial pressure in the rebreather is controlled, so it can be maintained at

9512-452: Is supplied to the diver at ambient pressure through a diving regulator . They may include additional cylinders for range extension, decompression gas or emergency breathing gas . Closed-circuit or semi-closed circuit rebreather scuba systems allow recycling of exhaled gases. The volume of gas used is reduced compared to that of open-circuit, so a smaller cylinder or cylinders may be used for an equivalent dive duration. Rebreathers extend

9676-510: Is the Sachsenspiegel , the first book of laws written in Middle Low German ( c.  1220 ). The abundance and especially the secular character of the literature of the MHG period demonstrate the beginnings of a standardized written form of German, as well as the desire of poets and authors to be understood by individuals on supra-dialectal terms. The Middle High German period

9840-750: Is the most spoken native language within the European Union . It is the most widely spoken and official (or co-official) language in Germany , Austria , Switzerland , Liechtenstein , and the Italian autonomous province of South Tyrol . It is also an official language of Luxembourg , Belgium and the Italian autonomous region of Friuli-Venezia Giulia , as well as a recognized national language in Namibia . There are also notable German-speaking communities in France ( Alsace ),

10004-566: Is the only language in this branch which survives in written texts. The West Germanic languages, however, have undergone extensive dialectal subdivision and are now represented in modern languages such as English, German, Dutch , Yiddish , Afrikaans , and others. Within the West Germanic language dialect continuum, the Benrath and Uerdingen lines (running through Düsseldorf - Benrath and Krefeld - Uerdingen , respectively) serve to distinguish

SECTION 60

#1732859020110

10168-481: Is understood in all areas where German is spoken. Approximate distribution of native German speakers (assuming a rounded total of 95 million) worldwide: As a result of the German diaspora , as well as the popularity of German taught as a foreign language , the geographical distribution of German speakers (or "Germanophones") spans all inhabited continents. However, an exact, global number of native German speakers

10332-402: Is upwards. The buoyancy of any object immersed in water is also affected by the density of the water. The density of fresh water is about 3% less than that of ocean water. Therefore, divers who are neutrally buoyant at one dive destination (e.g. a freshwater lake) will predictably be positively or negatively buoyant when using the same equipment at destinations with different water densities (e.g.

10496-422: Is usually provided by wetsuits or dry suits. These also provide protection from sunburn, abrasion and stings from some marine organisms. Where thermal insulation is not important, lycra suits/diving skins may be sufficient. A wetsuit is a garment, usually made of foamed neoprene, which provides thermal insulation, abrasion resistance and buoyancy. The insulation properties depend on bubbles of gas enclosed within

10660-673: The Ostsiedlung ). With the increasing wealth and geographic spread of the Germanic groups came greater use of German in the courts of nobles as the standard language of official proceedings and literature. A clear example of this is the mittelhochdeutsche Dichtersprache employed in the Hohenstaufen court in Swabia as a standardized supra-dialectal written language. While these efforts were still regionally bound, German began to be used in place of Latin for certain official purposes, leading to

10824-457: The 1971–72 Namibian contract workers strike over the contract labor system and apartheid . Tsumeb, since its founding, has been primarily a mining town. The mine was originally owned by the OMEG (Otavi Minen- und Eisenbahn-Gesellschaft) and later by TCL (Tsumeb Corporation Limited) before its closure a few years ago, when the ore at depth ran out. The main shafts became flooded by ground water over

10988-627: The Alamanni , Bavarian, and Thuringian groups, all belonging to the Elbe Germanic group ( Irminones ), which had settled in what is now southern-central Germany and Austria between the second and sixth centuries, during the great migration. In general, the surviving texts of Old High German (OHG) show a wide range of dialectal diversity with very little written uniformity. The early written tradition of OHG survived mostly through monasteries and scriptoria as local translations of Latin originals; as

11152-533: The Aqua-Lung trademark, which was first licensed to the U.S. Divers company, and in 1948 to Siebe Gorman of England. Siebe Gorman was allowed to sell in Commonwealth countries but had difficulty in meeting the demand and the U.S. patent prevented others from making the product. The patent was circumvented by Ted Eldred of Melbourne , Australia, who developed the single-hose open-circuit scuba system, which separates

11316-557: The Czech Republic ( North Bohemia ), Poland ( Upper Silesia ), Slovakia ( Košice Region , Spiš , and Hauerland ), Denmark ( North Schleswig ), Romania and Hungary ( Sopron ). Overseas, sizeable communities of German-speakers are found in Brazil ( Blumenau and Pomerode ), South Africa ( Kroondal ), Namibia , among others, some communities have decidedly Austrian German or Swiss German characters (e.g. Pozuzo , Peru). German

11480-507: The Duke University Medical Center Hyperbaric Laboratory started work which identified the use of trimix to prevent the symptoms of high-pressure nervous syndrome . Cave divers started using trimix to allow deeper dives and it was used extensively in the 1987 Wakulla Springs Project and spread to the north-east American wreck diving community. The challenges of deeper dives and longer penetrations and

11644-522: The Early Middle Ages . German is an inflected language , with four cases for nouns, pronouns, and adjectives (nominative, accusative, genitive, dative); three genders (masculine, feminine, neuter) and two numbers (singular, plural). It has strong and weak verbs . The majority of its vocabulary derives from the ancient Germanic branch of the Indo-European language family, while a smaller share

11808-417: The European Union 's population, spoke German as their mother tongue, making it the second most widely spoken language on the continent after Russian and the second biggest language in terms of overall speakers (after English), as well as the most spoken native language. The area in central Europe where the majority of the population speaks German as a first language and has German as a (co-)official language

11972-514: The German states . While these states were still part of the Holy Roman Empire , and far from any form of unification, the desire for a cohesive written language that would be understandable across the many German-speaking principalities and kingdoms was stronger than ever. As a spoken language German remained highly fractured throughout this period, with a vast number of often mutually incomprehensible regional dialects being spoken throughout

12136-724: The Holy Roman Emperor Maximilian I , and the other being Meißner Deutsch , used in the Electorate of Saxony in the Duchy of Saxe-Wittenberg . Alongside these courtly written standards, the invention of the printing press led to the development of a number of printers' languages ( Druckersprachen ) aimed at making printed material readable and understandable across as many diverse dialects of German as possible. The greater ease of production and increased availability of written texts brought about increased standardisation in

12300-644: The Old High German language in several Elder Futhark inscriptions from as early as the sixth century AD (such as the Pforzen buckle ), the Old High German period is generally seen as beginning with the Abrogans (written c.  765–775 ), a Latin-German glossary supplying over 3,000 Old High German words with their Latin equivalents. After the Abrogans , the first coherent works written in Old High German appear in

12464-823: The Professional Association of Diving Instructors (PADI) announced full educational support for nitrox. The use of a single nitrox mixture has become part of recreational diving, and multiple gas mixtures are common in technical diving to reduce overall decompression time. Technical diving is recreational scuba diving that exceeds the generally accepted recreational limits and may expose the diver to hazards beyond those normally associated with recreational diving, and to greater risks of serious injury or death. These risks may be reduced by appropriate skills, knowledge and experience, and by using suitable equipment and procedures. The concept and term are both relatively recent advents, although divers had already been engaging in what

12628-640: The Sprachraum in Europe. German is used in a wide variety of spheres throughout the country, especially in business, tourism, and public signage, as well as in education, churches (most notably the German-speaking Evangelical Lutheran Church in Namibia (GELK) ), other cultural spheres such as music, and media (such as German language radio programs by the Namibian Broadcasting Corporation ). The Allgemeine Zeitung

12792-536: The Standard German language in its written form, and the Duden Handbook was declared its standard definition. Punctuation and compound spelling (joined or isolated compounds) were not standardized in the process. The Deutsche Bühnensprache ( lit.   ' German stage language ' ) by Theodor Siebs had established conventions for German pronunciation in theatres , three years earlier; however, this

12956-503: The Upper German dialects spoken in the southern German-speaking countries , such as Swiss German ( Alemannic dialects ) and the various Germanic dialects spoken in the French region of Grand Est , such as Alsatian (mainly Alemannic, but also Central–and   Upper Franconian dialects) and Lorraine Franconian (Central Franconian). After these High German dialects, standard German

13120-401: The carbon dioxide is removed from the diver's exhaled breath which has oxygen added and is recirculated. Oxygen rebreathers are severely depth-limited due to oxygen toxicity risk, which increases with depth, and the available systems for mixed gas rebreathers were fairly bulky and designed for use with diving helmets. The first commercially practical scuba rebreather was designed and built by

13284-427: The history of scuba equipment . By the turn of the twentieth century, two basic architectures for underwater breathing apparatus had been pioneered; open-circuit surface supplied equipment where the diver's exhaled gas is vented directly into the water, and closed-circuit breathing apparatus where the diver's carbon dioxide is filtered from exhaled unused oxygen , which is then recirculated, and oxygen added to make up

13448-462: The pagan Germanic tradition. Of particular interest to scholars, however, has been the Hildebrandslied , a secular epic poem telling the tale of an estranged father and son unknowingly meeting each other in battle. Linguistically, this text is highly interesting due to the mixed use of Old Saxon and Old High German dialects in its composition. The written works of this period stem mainly from

13612-466: The technical diving community for general decompression diving , and has become a popular speciality for recreational diving. In the 1950s the United States Navy (USN) documented enriched oxygen gas procedures for military use of what is today called nitrox, and in 1970, Morgan Wells of NOAA began instituting diving procedures for oxygen-enriched air. In 1979 NOAA published procedures for

13776-466: The 'Tsumeb Ore Deposit' in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an IUGS Geological Heritage Site as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.' Near

13940-714: The Empire. Its use indicated that the speaker was a merchant or someone from an urban area, regardless of nationality. Prague (German: Prag ) and Budapest ( Buda , German: Ofen ), to name two examples, were gradually Germanized in the years after their incorporation into the Habsburg domain; others, like Pressburg ( Pozsony , now Bratislava), were originally settled during the Habsburg period and were primarily German at that time. Prague, Budapest, Bratislava, and cities like Zagreb (German: Agram ) or Ljubljana (German: Laibach ), contained significant German minorities. In

14104-718: The Frisian languages— North Frisian (spoken in Nordfriesland ), Saterland Frisian (spoken in Saterland ), and West Frisian (spoken in Friesland )—as well as the Anglic languages of English and Scots. These Anglo-Frisian dialects did not take part in the High German consonant shift, and the Anglic languages also adopted much vocabulary from both Old Norse and the Norman language . The history of

14268-524: The German language begins with the High German consonant shift during the Migration Period , which separated Old High German dialects from Old Saxon . This sound shift involved a drastic change in the pronunciation of both voiced and voiceless stop consonants ( b , d , g , and p , t , k , respectively). The primary effects of the shift were the following below. While there is written evidence of

14432-447: The German states; the invention of the printing press c.  1440 and the publication of Luther's vernacular translation of the Bible in 1534, however, had an immense effect on standardizing German as a supra-dialectal written language. The ENHG period saw the rise of several important cross-regional forms of chancery German, one being gemeine tiutsch , used in the court of

14596-675: The Germanic dialects that were affected by the High German consonant shift (south of Benrath) from those that were not (north of Uerdingen). The various regional dialects spoken south of these lines are grouped as High German dialects, while those spoken to the north comprise the Low German and Low Franconian dialects. As members of the West Germanic language family, High German, Low German, and Low Franconian have been proposed to be further distinguished historically as Irminonic , Ingvaeonic , and Istvaeonic , respectively. This classification indicates their historical descent from dialects spoken by

14760-646: The Irminones (also known as the Elbe group), Ingvaeones (or North Sea Germanic group), and Istvaeones (or Weser–Rhine group). Standard German is based on a combination of Thuringian - Upper Saxon and Upper Franconian dialects, which are Central German and Upper German dialects belonging to the High German dialect group. German is therefore closely related to the other languages based on High German dialects, such as Luxembourgish (based on Central Franconian dialects ) and Yiddish . Also closely related to Standard German are

14924-507: The MHG period. Significantly, these texts include a number of impressive secular works, such as the Nibelungenlied , an epic poem telling the story of the dragon -slayer Siegfried ( c.  thirteenth century ), and the Iwein , an Arthurian verse poem by Hartmann von Aue ( c.  1203 ), lyric poems , and courtly romances such as Parzival and Tristan . Also noteworthy

15088-417: The average lung volume in open-circuit scuba, but this feature is not available to the closed circuit rebreather diver, as exhaled gas remains in the breathing loop. This is a skill that improves with practice until it becomes second nature. Buoyancy changes with depth variation are proportional to the compressible part of the volume of the diver and equipment, and to the proportional change in pressure, which

15252-400: The breathing apparatus, diving suit , buoyancy control and weighting systems, fins for mobility, mask for improving underwater vision, and a variety of safety equipment and other accessories. The defining equipment used by a scuba diver is the eponymous scuba , the self-contained underwater breathing apparatus which allows the diver to breathe while diving, and is transported by the diver. It

15416-477: The buoyancy of a lifting device such as a buoyancy compensator, inflatable surface marker buoy or small lifting bag. The breathing gas is generally provided from a high-pressure diving cylinder through a scuba regulator. By always providing the appropriate breathing gas at ambient pressure, demand valve regulators ensure the diver can inhale and exhale naturally and without excessive effort, regardless of depth, as and when needed. The most commonly used scuba set uses

15580-553: The city. SWAPO won with approximately 75% of the vote. Of the four other parties seeking seats, Rally for Democracy and Progress (RDP) received approximately 15% of the vote, followed by United Democratic Front (UDF, 5%), All People's Party (APP, 2%), and the Democratic Turnhalle Alliance (DTA, 2%) Despite being on the ballot, the Congress of Democrats (CoD) did not receive a vote. The 2015 local authority election

15744-445: The cold inside of the faceplate. To prevent fogging many divers spit into the dry mask before use, spread the saliva over the inside of the glass and rinse it out with a little water. The saliva residue allows condensation to wet the glass and form a continuous wet film, rather than tiny droplets. There are several commercial products that can be used as an alternative to saliva, some of which are more effective and last longer, but there

15908-426: The compression effect and squeeze . Buoyancy compensators allow easy and fine adjustments in the diver's overall volume and therefore buoyancy. Neutral buoyancy in a diver is an unstable state. It is changed by small differences in ambient pressure caused by a change in depth, and the change has a positive feedback effect. A small descent will increase the pressure, which will compress the gas-filled spaces and reduce

16072-433: The cylinder. Less common are closed circuit (CCR) and semi-closed (SCR) rebreathers which, unlike open-circuit sets that vent off all exhaled gases, process all or part of each exhaled breath for re-use by removing the carbon dioxide and replacing the oxygen used by the diver. Rebreathers release few or no gas bubbles into the water, and use much less stored gas volume, for an equivalent depth and time because exhaled oxygen

16236-424: The depth and duration of a dive to avoid decompression sickness. Traditionally this was done by using a depth gauge and a diving watch, but electronic dive computers are now in general use, as they are programmed to do real-time modelling of decompression requirements for the dive, and automatically allow for surface interval. Many can be set for the gas mixture to be used on the dive, and some can accept changes in

16400-448: The depth reachable by underwater divers when breathing nitrox mixtures. In 1924 the US Navy started to investigate the possibility of using helium and after animal experiments, human subjects breathing heliox 20/80 (20% oxygen, 80% helium) were successfully decompressed from deep dives, In 1963 saturation dives using trimix were made during Project Genesis , and in 1979 a research team at

16564-430: The development of non-local forms of language and exposed all speakers to forms of German from outside their own area. With Luther's rendering of the Bible in the vernacular, German asserted itself against the dominance of Latin as a legitimate language for courtly, literary, and now ecclesiastical subject-matter. His Bible was ubiquitous in the German states: nearly every household possessed a copy. Nevertheless, even with

16728-452: The dialect so as to make the work as natural and accessible to German speakers as possible. Copies of Luther's Bible featured a long list of glosses for each region, translating words which were unknown in the region into the regional dialect. Luther said the following concerning his translation method: One who would talk German does not ask the Latin how he shall do it; he must ask the mother in

16892-399: The direction of intended motion and will reduce induced drag. Streamlining dive gear will also reduce drag and improve mobility. Balanced trim which allows the diver to align in any desired direction also improves streamlining by presenting the smallest section area to the direction of movement and allowing propulsion thrust to be used more efficiently. Occasionally a diver may be towed using

17056-514: The dive. Buoyancy and trim can significantly affect drag of a diver. The effect of swimming with a head up angle of about 15°, as is quite common in poorly trimmed divers, can be an increase in drag in the order of 50%. The ability to ascend at a controlled rate and remain at a constant depth is important for correct decompression. Recreational divers who do not incur decompression obligations can get away with imperfect buoyancy control, but when long decompression stops at specific depths are required,

17220-418: The diver is competent in their use. The most commonly used mixture is nitrox, also referred to as Enriched Air Nitrox (EAN or EANx), which is air with extra oxygen, often with 32% or 36% oxygen, and thus less nitrogen, reducing the risk of decompression sickness or allowing longer exposure to the same pressure for equal risk. The reduced nitrogen may also allow for no stops or shorter decompression stop times or

17384-435: The diver to breathe through the nose. Professional scuba divers are more likely to use full-face masks, which protect the diver's airway if the diver loses consciousness. Open-circuit scuba has no provision for using the breathing gas more than once for respiration. The gas inhaled from the scuba equipment is exhaled to the environment, or occasionally into another item of equipment for a special purpose, usually to increase

17548-475: The diver to carry an alternative gas supply sufficient to allow the diver to safely reach a place where more breathing gas is available. For open water recreational divers this is the surface. A bailout cylinder provides emergency breathing gas sufficient for a safe emergency ascent. For technical divers on a penetration dive, it may be a stage cylinder positioned at a point on the exit path. An emergency gas supply must be sufficiently safe to breathe at any point on

17712-467: The diver to navigate, a compass may be carried, and where retracing a route is critical, as in cave or wreck penetrations, a guide line is laid from a dive reel. In less critical conditions, many divers simply navigate by landmarks and memory, a procedure also known as pilotage or natural navigation. A scuba diver should always be aware of the remaining breathing gas supply, and the duration of diving time that this will safely support, taking into account

17876-669: The diver's back, usually bottom gas. To take advantage of the freedom of movement afforded by scuba equipment, the diver needs to be mobile underwater. Personal mobility is enhanced by swimfins and optionally diver propulsion vehicles. Fins have a large blade area and use the more powerful leg muscles, so are much more efficient for propulsion and manoeuvering thrust than arm and hand movements, but require skill to provide fine control. Several types of fin are available, some of which may be more suited for maneuvering, alternative kick styles, speed, endurance, reduced effort or ruggedness. Neutral buoyancy will allow propulsive effort to be directed in

18040-559: The diver, clipped to the harness below the shoulders and along the hips, instead of on the back of the diver. It originated as a configuration for advanced cave diving , as it facilitates penetration of tight sections of caves since sets can be easily removed and remounted when necessary. The configuration allows easy access to cylinder valves and provides easy and reliable gas redundancy. These benefits for operating in confined spaces were also recognized by divers who made wreck diving penetrations. Sidemount diving has grown in popularity within

18204-508: The diving engineer Henry Fleuss in 1878, while working for Siebe Gorman in London. His self-contained breathing apparatus consisted of a rubber mask connected to a breathing bag, with an estimated 50–60% oxygen supplied from a copper tank and carbon dioxide scrubbed by passing it through a bundle of rope yarn soaked in a solution of caustic potash, the system giving a dive duration of up to about three hours. This apparatus had no way of measuring

18368-507: The eastern provinces of Banat , Bukovina , and Transylvania (German: Banat, Buchenland, Siebenbürgen ), German was the predominant language not only in the larger towns—like Temeschburg ( Timișoara ), Hermannstadt ( Sibiu ), and Kronstadt ( Brașov )—but also in many smaller localities in the surrounding areas. In 1901, the Second Orthographic Conference ended with a (nearly) complete standardization of

18532-400: The equipment and dealing with the general hazards of the underwater environment , and emergency procedures for self-help and assistance of a similarly equipped diver experiencing problems. A minimum level of fitness and health is required by most training organisations, but a higher level of fitness may be appropriate for some applications. The history of scuba diving is closely linked with

18696-442: The equipment they are breathing from at the time. Several systems are in common use depending on the planned dive profile. Most common, but least reliable, is relying on the dive buddy for gas sharing using a secondary second stage, commonly called an octopus regulator connected to the primary first stage. This system relies entirely on the dive buddy being immediately available to provide emergency gas. More reliable systems require

18860-509: The first stage and demand valve of the pressure regulator by a low-pressure hose, puts the demand valve at the diver's mouth, and releases exhaled gas through the demand valve casing. Eldred sold the first Porpoise Model CA single-hose scuba early in 1952. Early scuba sets were usually provided with a plain harness of shoulder straps and a waist belt. The waist belt buckles were usually quick-release, and shoulder straps sometimes had adjustable or quick-release buckles. Many harnesses did not have

19024-403: The front and sides of the diver for other equipment to be attached in the region where it is easily accessible. This additional equipment is usually suspended from the harness or carried in pockets on the exposure suit. Sidemount is a scuba diving equipment configuration which has basic scuba sets , each comprising a single cylinder with a dedicated regulator and pressure gauge, mounted alongside

19188-697: The gas composition during use. During the 1930s and all through World War II , the British, Italians and Germans developed and extensively used oxygen rebreathers to equip the first frogmen . The British adapted the Davis Submerged Escape Apparatus and the Germans adapted the Dräger submarine escape rebreathers, for their frogmen during the war. In the U.S. Major Christian J. Lambertsen invented an underwater free-swimming oxygen rebreather in 1939, which

19352-432: The gas mix during the dive. Most dive computers provide a fairly conservative decompression model, and the level of conservatism may be selected by the user within limits. Most decompression computers can also be set for altitude compensation to some degree, and some will automatically take altitude into account by measuring actual atmospheric pressure and using it in the calculations. If the dive site and dive plan require

19516-435: The home, the children on the streets, the common man in the market-place and note carefully how they talk, then translate accordingly. They will then understand what is said to them because it is German. When Christ says ' ex abundantia cordis os loquitur ,' I would translate, if I followed the papists, aus dem Überflusz des Herzens redet der Mund . But tell me is this talking German? What German understands such stuff? No,

19680-450: The housing mounted to the cylinder valve or manifold. The "single-hose" system has significant advantages over the original system for most applications. In the "single-hose" two-stage design, the first stage regulator reduces the cylinder pressure of up to about 300 bars (4,400 psi) to an intermediate pressure (IP) of about 8 to 10 bars (120 to 150 psi) above ambient pressure. The second stage demand valve regulator, supplied by

19844-474: The influence of Luther's Bible as an unofficial written standard, a widely accepted standard for written German did not appear until the middle of the eighteenth century. German was the language of commerce and government in the Habsburg Empire , which encompassed a large area of Central and Eastern Europe . Until the mid-nineteenth century, it was essentially the language of townspeople throughout most of

20008-429: The large amounts of breathing gas necessary for these dive profiles and ready availability of oxygen-sensing cells beginning in the late 1980s led to a resurgence of interest in rebreather diving. By accurately measuring the partial pressure of oxygen, it became possible to maintain and accurately monitor a breathable gas mixture in the loop at any depth. In the mid-1990s semi-closed circuit rebreathers became available for

20172-480: The largest and deepest underground lakes in the world lies a little to the east of Tsumeb, on a farm called Harasib . To reach the water in the cave one has either to abseil or to descend an ancient, hand-forged ladder that hangs free of the vertical dolomite walls of the cave for over 50 m. Here, too, SCUBA divers have descended as deep as they have dared (80 m) in the crystal-clear waters and have reported nothing but deep blue below them from one ledge of dolomite to

20336-428: The largest concentrations of German speakers are in the states of Rio Grande do Sul (where Riograndenser Hunsrückisch developed), Santa Catarina , and Espírito Santo . Scuba diving Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba

20500-592: The last weekend of October at the United Nations Park. The four-day event, which is aimed at boosting the economic competitiveness of the town, draws crowds from all corners of the country and beyond. It also facilitates indirect investments in the hospitality sector. The Evaristus Shikongo Correctional Facility in Tsumeb is one of Namibia's seven major prisons. Tsumeb's stadium, the Oscar Norich Stadium, has

20664-540: The lowest reasonably practicable risk. Ideally the diver should practice precise buoyancy control when the risk of decompression sickness due to depth variation violating the decompression ceiling is low. Water has a higher refractive index than air – similar to that of the cornea of the eye. Light entering the cornea from water is hardly refracted at all, leaving only the eye's crystalline lens to focus light. This leads to very severe hypermetropia . People with severe myopia , therefore, can see better underwater without

20828-466: The material, which reduce its ability to conduct heat. The bubbles also give the wetsuit a low density, providing buoyancy in water. Suits range from a thin (2 mm or less) "shortie", covering just the torso, to a full 8 mm semi-dry, usually complemented by neoprene boots, gloves and hood. A good close fit and few zips help the suit to remain waterproof and reduce flushing – the replacement of water trapped between suit and body by cold water from

20992-429: The mine produced about 30 million tons of ore yielding 1.7 Mt copper, 2.8 Mt lead 0.9 Mt zinc, as well as 80 t germanium. The average ore grade was 10% Pb, 4.3% Cu, 3.5% Zn, 100 ppm Ag, 50 ppm Ge. It is noted for 243 valid minerals and is the type location for 56 types of mineral. Some of the germanium minerals are only found in this mine. From 1971 to 1972, the Tsumeb mine had its operations temporarily stopped during

21156-402: The mother in the home and the plain man would say, Wesz das Herz voll ist, des gehet der Mund über . Luther's translation of the Bible into High German was also decisive for the German language and its evolution from Early New High German to modern Standard German. The publication of Luther's Bible was a decisive moment in the spread of literacy in early modern Germany , and promoted

21320-513: The national railway network operated by TransNamib . Tsumeb was for most of the 20th century the terminus of the line but in recent times the track has been extended a further 260 km to reach Ondangwa . There have been talks of extending the line to Oshikango and having the Government of Angola build a railroad from the north to connect the two countries together. The junction for the Ondangwa line

21484-585: The new name of the DTA) with 199 votes. Tsumeb has a hot semi-arid climate ( Köppen : BSh ), with hot summers and mild winters (with warm days and chilly nights). The average annual precipitation is 528 mm (21 in). Tsumeb belongs to the world's most prolific mineralogical sites. The minerals from Tsumeb are unsurpassed in variety and quality of form. At least 170 mineral species have been cataloged and 20 of these are found nowhere else. The concentration of ingredients for Tsumeb's mineral formations originates in

21648-435: The next with nothing discernible in the depths. The largest meteorite in the world, called Hoba , lies in a field about forty minutes' drive to the southeast of Tsumeb, at Hoba West. It is a nickel-iron meteorite of about 60 tonnes. There are 105 commercial farms around Tsumeb. The area consists largely of rolling hills covered in thorn bush. Tsumeb falls under the dry woodland, savanna vegetation zone. Much of farmland

21812-630: The ninth century, chief among them being the Muspilli , Merseburg charms , and Hildebrandslied , and other religious texts (the Georgslied , Ludwigslied , Evangelienbuch , and translated hymns and prayers). The Muspilli is a Christian poem written in a Bavarian dialect offering an account of the soul after the Last Judgment , and the Merseburg charms are transcriptions of spells and charms from

21976-409: The outside. Improved seals at the neck, wrists and ankles and baffles under the entry zip produce a suit known as "semi-dry". A dry suit also provides thermal insulation to the wearer while immersed in water, and normally protects the whole body except the head, hands, and sometimes the feet. In some configurations, these are also covered. Dry suits are usually used where the water temperature

22140-410: The overall buoyancy. When divers want to remain at constant depth, they try to achieve neutral buoyancy. This minimises the effort of swimming to maintain depth and therefore reduces gas consumption. The buoyancy force on the diver is the weight of the volume of the liquid that they and their equipment displace minus the weight of the diver and their equipment; if the result is positive , that force

22304-469: The planned dive profile at which it may be needed. This equipment may be a bailout cylinder , a bailout rebreather , a travel gas cylinder, or a decompression gas cylinder. When using a travel gas or decompression gas, the back gas (main gas supply) may be the designated emergency gas supply. Cutting tools such as knives, line cutters or shears are often carried by divers to cut loose from entanglement in nets or lines. A surface marker buoy (SMB) on

22468-464: The presence of the divers. The high percentage of oxygen used by these early rebreather systems limited the depth at which they could be used due to the risk of convulsions caused by acute oxygen toxicity . Although a working demand regulator system had been invented in 1864 by Auguste Denayrouze and Benoît Rouquayrol , the first open-circuit scuba system developed in 1925 by Yves Le Prieur in France

22632-462: The pronunciation of the ending -ig as [ɪk] instead of [ɪç]. In Northern Germany, High German was a foreign language to most inhabitants, whose native dialects were subsets of Low German. It was usually encountered only in writing or formal speech; in fact, most of High German was a written language, not identical to any spoken dialect, throughout the German-speaking area until well into the 19th century. However, wider standardization of pronunciation

22796-430: The recovery of this metal was always difficult for technical reasons. Many millions of tonnes of ore of spectacular grade were removed. A good percentage of the ore (called "direct smelting ore") was so rich that it was sent straight to the smelter situated near the town without having to be processed through the mineral enrichment plant. The Tsumeb mine is also renowned amongst mineral collectors . Between 1905 and 1996,

22960-424: The recreational scuba market, followed by closed circuit rebreathers around the turn of the millennium. Rebreathers are currently manufactured for the military, technical and recreational scuba markets, but remain less popular, less reliable, and more expensive than open-circuit equipment. Scuba diving equipment, also known as scuba gear, is the equipment used by a scuba diver for the purpose of diving, and includes

23124-417: The risk of decompression sickness is increased by depth variations while at a stop. Decompression stops are typically done when the breathing gas in the cylinders has been largely used up, and the reduction in weight of the cylinders increases the buoyancy of the diver. Enough weight must be carried to allow the diver to decompress at the end of the dive with nearly empty cylinders. Depth control during ascent

23288-400: The rock filling it (the "pseudo-aplite") is peculiar in the extreme. The pipe was mined in prehistoric times but those ancient workers barely scratched the surface. Most of the ore was removed in the 20th century by cut-and-fill methods. The ore was polymetallic and from it copper , lead , silver , gold , arsenic and germanium were won. There was also a fair amount of zinc present but

23452-464: The scientific use of nitrox in the NOAA Diving Manual. In 1985 IAND (International Association of Nitrox Divers) began teaching nitrox use for recreational diving. This was considered dangerous by some, and met with heavy skepticism by the diving community. Nevertheless, in 1992 NAUI became the first existing major recreational diver training agency to sanction nitrox, and eventually, in 1996,

23616-541: The states of North Dakota and South Dakota , German is the most common language spoken at home after English. As a legacy of significant German immigration to the country , German geographical names can be found throughout the Midwest region , such as New Ulm and Bismarck (North Dakota's state capital), plus many other regions. A number of German varieties have developed in the country and are still spoken today, such as Pennsylvania Dutch and Texas German . In Brazil,

23780-416: The suit must be inflated and deflated with changes in depth in order to avoid "squeeze" on descent or uncontrolled rapid ascent due to over-buoyancy. Dry suit divers may also use the gas argon to inflate their suits via low pressure inflator hose. This is because the gas is inert and has a low thermal conductivity. Unless the maximum depth of the water is known, and is quite shallow, a diver must monitor

23944-411: The surface, a cutting tool to manage entanglement, lights , a dive computer to monitor decompression status , and signalling devices . Scuba divers are trained in the procedures and skills appropriate to their level of certification by diving instructors affiliated to the diver certification organisations which issue these certifications. These include standard operating procedures for using

24108-502: The surface, and that can be quickly inflated. The first versions were inflated from a small disposable carbon dioxide cylinder, later with a small direct coupled air cylinder. A low-pressure feed from the regulator first-stage to an inflation/deflation valve unit an oral inflation valve and a dump valve lets the volume of the ABLJ be controlled as a buoyancy aid. In 1971 the stabilizer jacket was introduced by ScubaPro . This class of buoyancy aid

24272-496: The third most commonly learned second language in the United States in K-12 education. The language has been influential in the fields of philosophy, theology, science, and technology. It is the second most commonly used language in science and the third most widely used language on websites . The German-speaking countries are ranked fifth in terms of annual publication of new books, with one-tenth of all books (including e-books) in

24436-400: The time required to surface safely and an allowance for foreseeable contingencies. This is usually monitored by using a submersible pressure gauge on each cylinder. Any scuba diver who will be diving below a depth from which they are competent to do a safe emergency swimming ascent should ensure that they have an alternative breathing gas supply available at all times in case of a failure of

24600-402: The time spent underwater compared to open-circuit for the same metabolic gas consumption; they produce fewer bubbles and less noise than open-circuit scuba, which makes them attractive to covert military divers to avoid detection, scientific divers to avoid disturbing marine animals, and media divers to avoid bubble interference. Scuba diving may be done recreationally or professionally in

24764-430: The total volume of diver and equipment. This will further reduce the buoyancy, and unless counteracted, will result in sinking more rapidly. The equivalent effect applies to a small ascent, which will trigger an increased buoyancy and will result in an accelerated ascent unless counteracted. The diver must continuously adjust buoyancy or depth in order to remain neutral. Fine control of buoyancy can be achieved by controlling

24928-401: The town are two large sinkhole lakes, Lake Otjikoto and Lake Guinas ("Gwee-nus"). Guinas, at about 500 m in diameter, is somewhat larger in area than Otjikoto. A pioneering documentary movie about scuba diving in these lakes was made by Graham Ferreira in the early 1970s. The depths of the lakes are unknown, because towards the bottom both lakes disappear into lateral cave systems, so it

25092-410: The volume when necessary. Closed circuit equipment was more easily adapted to scuba in the absence of reliable, portable, and economical high-pressure gas storage vessels. By the mid-twentieth century, high pressure gas cylinders were available and two systems for scuba had emerged: open-circuit scuba where the diver's exhaled breath is vented directly into the water, and closed-circuit scuba where

25256-422: The water and be able to maintain a constant depth in midwater. Ignoring other forces such as water currents and swimming, the diver's overall buoyancy determines whether they ascend or descend. Equipment such as diving weighting systems , diving suits (wet, dry or semi-dry suits are used depending on the water temperature) and buoyancy compensators(BC) or buoyancy control device(BCD) can be used to adjust

25420-543: The world being published in German. German is most closely related to other West Germanic languages, namely Afrikaans , Dutch , English , the Frisian languages , and Scots . It also contains close similarities in vocabulary to some languages in the North Germanic group , such as Danish , Norwegian , and Swedish . Modern German gradually developed from Old High German , which in turn developed from Proto-Germanic during

25584-579: The written form of German. One of the central events in the development of ENHG was the publication of Luther's translation of the Bible into High German (the New Testament was published in 1522; the Old Testament was published in parts and completed in 1534). Luther based his translation primarily on the Meißner Deutsch of Saxony , spending much time among the population of Saxony researching

25748-429: Was a "neutral" language as there were virtually no English native speakers in Namibia at that time. German, Afrikaans, and several indigenous languages thus became "national languages" by law, identifying them as elements of the cultural heritage of the nation and ensuring that the state acknowledged and supported their presence in the country. Today, Namibia is considered to be the only German-speaking country outside of

25912-522: Was a manually adjusted free-flow system with a low endurance, which limited its practical usefulness. In 1942, during the German occupation of France , Jacques-Yves Cousteau and Émile Gagnan designed the first successful and safe open-circuit scuba, known as the Aqua-Lung . Their system combined an improved demand regulator with high-pressure air tanks. This was patented in 1945. To sell his regulator in English-speaking countries Cousteau registered

26076-498: Was accepted by the Office of Strategic Services . In 1952 he patented a modification of his apparatus, this time named SCUBA (an acronym for "self-contained underwater breathing apparatus"), which became the generic English word for autonomous breathing equipment for diving, and later for the activity using the equipment. After World War II, military frogmen continued to use rebreathers since they do not make bubbles which would give away

26240-593: Was again won by SWAPO which gained six seats and 3,149 votes. The remaining seat went to the DTA which gained 291 votes. The 2020 local authority election was also won by SWAPO which obtained 2,518 votes and gained four seats. The Independent Patriots for Change (IPC), an opposition party formed in August 2020, obtained 1,472 votes and gained two seats. The remaining seat went to the Popular Democratic Movement (PDM,

26404-530: Was an artificial standard that did not correspond to any traditional spoken dialect. Rather, it was based on the pronunciation of German in Northern Germany, although it was subsequently regarded often as a general prescriptive norm, despite differing pronunciation traditions especially in the Upper-German-speaking regions that still characterise the dialect of the area today – especially

26568-485: Was established on the basis of public speaking in theatres and the media during the 20th century and documented in pronouncing dictionaries. Official revisions of some of the rules from 1901 were not issued until the controversial German orthography reform of 1996 was made the official standard by governments of all German-speaking countries. Media and written works are now almost all produced in Standard German which

26732-439: Was nothing but powdery-blue water below them. Guinas has been in existence for so long that a unique species of fish, Tilapia guinasana , has evolved in its waters. When South Africa invaded German Southwest Africa , today's Namibia, in 1914, the retreating German forces eventually threw all of their weaponry and supplies into the deep waters of Otjikoto. Some of the material has been recovered for display in museums. One of

26896-478: Was sold by Weatherly International mining company to Dundee Corporation in 2010. The right of the smelter is currently owned by IXM . The Annual Copper Festival is a well-known event on the local festival calendar. In respect of it being 'one of the richest ore deposits with respect to variety, rarity and aesthetics of minerals in the world', the International Union of Geological Sciences (IUGS) included

#109890