SUMMARY / RELATED TOPICS

10BASE2

10BASE2 is a variant of Ethernet that uses thin coaxial cable terminated with BNC connectors to build a local area network. During the mid to late 1980s this was the dominant 10 Mbit/s Ethernet standard, but due to the immense demand for high speed networking, the low cost of Category 5 cable, the popularity of 802.11 wireless networks, both 10BASE2 and 10BASE5 have become obsolete, though devices still exist in some locations. As of 2011, IEEE 802.3 has deprecated this standard for new installations. The name 10BASE2 is derived from several characteristics of the physical medium; the 10 comes from the transmission speed of 10 Mbit/s. The BASE stands for baseband signalling, the 2 for a maximum segment length approaching 200 m. 10 Mbit/s Ethernet uses Manchester coding. A binary zero is indicated by a low-to-high transition in the middle of the bit period and a binary one is indicated by a high-to-low transition in the middle of the bit period. Manchester coding allows the clock to be recovered from the signal.

However, the additional transitions associated with it double the signal bandwidth. 10BASE2 coax cables have a maximum length of 185 metres. The maximum practical number of nodes that can be connected to a 10BASE2 segment is limited to 30 with a minimum distance of 50 centimetres between devices. In a 10BASE2 network, each stretch of cable is connected to the transceiver using a BNC T-connector, with one stretch connected to each female connector of the T; the T-connector must be plugged directly into the network adaptor with no cable in between. As is the case with most other high-speed buses, Ethernet segments have to be terminated with a resistor at each end; each end of the cable has a 50 ohm resistor attached. This resistor is built into a male BNC and attached to the last device on the bus; this is most connected directly to the T-connector on a workstation. If termination is missing, or if there is a break in the cable, the AC signal on the bus is reflected, rather than dissipated, when it reaches the end.

This reflected signal is indistinguishable from a collision, so no communication can take place. Some terminators have a metallic chain attached to them for grounding purposes; the cable should be grounded at one end. Grounding the terminators at both may produce a ground loop and can cause network outages or data corruption when swells of electricity traverse the coaxial cabling's outer shield; when wiring a 10BASE2 network, special care has to be taken to ensure that cables are properly connected to all T-connectors. Bad contacts or shorts are difficult to diagnose. A failure at any point of the network cabling tends to prevent all communications. For this reason, 10BASE2 networks can be difficult to maintain and were replaced by 10BASE-T networks, which provided a good upgrade path to 100BASE-TX. 10BASE2 networks cannot be extended without breaking service temporarily for existing users and the presence of many joints in the cable makes them vulnerable to accidental or malicious disruption.

There were proprietary systems that claimed to avoid these problems but these never became widespread due to a lack of standardization. 10BASE-T can be extended by making a new connection to a hub. A fault in a one hub connection does not compromise other connections to the hub. 10BASE2 systems do have a number of advantages over 10BASE-T. No hub is required as with 10BASE-T, so the hardware cost is minimal, wiring can be easy since only a single wire run is needed, which can be sourced from the nearest computer; these characteristics mean that 10BASE2 is ideal for a small network of two or three machines in a home where concealed wiring may be an advantage. For a larger complex office network, the difficulties of tracing poor connections make it impractical. For 10BASE2, by the time multiple home computer networks became common, the format had been superseded by 10BASE-T. 10BASE2 uses RG-58A/U cable or similar for a maximum segment length of 185 m as opposed to the thicker RG-8-like cable used in 10BASE5 networks with a maximum length of 500 m.

The RG-58 type wire used by 10BASE2 in addition to being smaller and much more flexible than the specialized RG-8 variant, was inexpensive. An Ethernet network interface controller may include the 10BASE2 transceivers and thus directly provide a 10BASE2 BNC connector, or it may offer an AUI connector that external transceivers can connect to; these can be transceivers for 10BASE2, but for 10BASE5 or 10BASE-T. Some NICs offer both BNC and AUI connectors, or other combinations including BNC and 10BASE-T. With multiple connections, only one connector is designed to be used at the same time. List of network buses This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later

Ajdovščina

Ajdovščina is a small town with a population of about 6,700, located in the Vipava Valley, Slovenia. It is the administrative centre of the Municipality of Ajdovščina; the first mentions of Ajdovščina go back to circa 2000 BC. In the Bronze Age and the Iron Age a fortified settlement stood on the nearby hill of Gradišče. In the early period of the Roman Empire, after a road was built from Aquileia towards Emona, a small post and goods station known as mansio Fluvio Frigido stood on the site of today's Ajdovščina. In the late 3rd century and the early 4th century a fortification system, Claustra Alpium Iuliarum, which run from the Kvarner Gulf to Cividale, was built by the Roman Empire, its centre was the fortress of Castra or Castrum ad Fluvio Frigido, the remains of which are today still visible in Ajdovščina. Despite the fact that the Italian border is less than 20 km away and that Ajdovščina was under Italian administration from 1918 to 1947, from 1927 as a commune of the Province of Gorizia, during Italian rule, the style of the town does not resemble that of a typical Italian town.

The strong bora winds would cause damage to the usual Italian house construction. Thus the population modified the classical Karst architecture for their own needs. After World War II Ajdovščina became the cultural centre of the upper Vipava Valley. Major industries include textile fabrics, food and furniture. Ajdovščina annexed the independent settlement of Šturje in 1953; the Hubelj River is the dividing line between the two largest parts of Ajdovščina, locally known as Šturje and Ajdovščina. During the pre-World War I years the river was the border between the Austrian lands of Gorizia and Gradisca and Carniola; the climate is Mediterranean (minimum temperature in winter −1 °C, maximum 17 °C. The town is located around 25 km from the Adriatic Sea; the parish church in Ajdovščina is dedicated to John the Baptist and belongs to the Diocese of Koper. It is built on the site of a Roman cemetery, its interior was painted by the local Baroque painter Anton Čebej. A second parish within the urban area of Ajdovščina is the Parish of Šturje, with the parish church dedicated to Saint George.

The church in the hamlet of Fužine north of the main town, dedicated to Saint Anthony of Padua belongs to this parish. Ivo Boscarol, businessman Anton Čebej, painter Miša Cigoj, dancesport athlete Milan Klemenčič, puppeteer Karel Lavrič, politician Danilo Lokar, author Julij Mayer, beekeeper Veno Pilon, painter Avgust Žigon, literary historian NK Primorje Ajdovščina municipal page ] Ajdovščina on Geopedia Ajdovščina Tourist Information Centre site Virtual Ajdovščina by Burger

Cyclone Monica

Severe Tropical Cyclone Monica was the most intense tropical cyclone, in terms of maximum sustained winds, on record to impact Australia, tied with Cyclone Marcus in 2018. The 17th and final storm of the 2005–06 Australian region cyclone season, Monica originated from an area of low pressure off the coast of Papua New Guinea on 16 April 2006; the storm developed into a Category 1 cyclone the next day, at which time it was given the name Monica. Travelling towards the west, the storm intensified into a severe tropical cyclone before making landfall in Far North Queensland, near Lockhart River, on 19 April 2006. After moving over land, convection associated with the storm became disorganised. On 20 April 2006, Monica began to re-intensify. Over the following few days, deep convection formed around a 37 km wide eye. Early on 22 April 2006, the Bureau of Meteorology assessed Monica to have attained Category 5 status, on the Australian cyclone intensity scale; the Joint Typhoon Warning Center upgraded Monica to a Category 5 equivalent cyclone, on the Saffir–Simpson Hurricane Scale.

The storm attained its peak intensity the following day with winds of 250 km/h and a barometric pressure of 916 hPa. On 24 April 2006, Monica made landfall at the same intensity. Rapid weakening took place as the storm moved over land. Less than 24 hours after landfall, the storm had weakened to a tropical low; the remnants of the former-Category 5 cyclone persisted until 28 April 2006 over northern Australia. In contrast to the extreme intensity of the cyclone little structural damage resulted from it. No injuries were reported to have occurred during the storm's existence and losses were estimated to be A$6.6 million. However, severe environmental damage took place. In the Northern Territory, an area about 7,000 km2 was defoliated by Monica's high wind gusts. In response to the large loss of forested area, it was stated that it would take several hundred years for the area to reflourish. Severe Tropical Cyclone Monica originated from an area of low pressure that formed early on 16 April 2006 off the coast of Papua New Guinea.

The low became organised, with deep convection developing over the low-pressure centre. That day, the Joint Typhoon Warning Center issued a Tropical Cyclone Formation Alert as the system became organised. Early the next day, the Bureau of Meteorology in Brisbane, Australia declared that the low had developed into a Category 1 cyclone on the Australian tropical cyclone scale, with winds reaching 65 km/h. Upon being classified as a cyclone, the storm was given the name Monica. At the same time, the JTWC designated Monica as Tropical Cyclone 23P. Monica tracked westward, towards Far North Queensland, in response to a low to mid-level ridge to the south. Low wind shear and good divergence in the path of the storm allowed for continued intensification as continued westward. Late on 17 April, Monica intensified with winds reaching 95 km/h. By 1200 UTC on 18 April, the Bureau of Meteorology upgraded Monica to a severe tropical cyclone, a Category 3 on the Australian scale; this followed an increase in a fluctuating central dense overcast.

Several hours the JTWC upgraded Monica to the equivalent of a Category 1 hurricane on the Saffir–Simpson Hurricane Scale. During the afternoon of 19 April, the storm made landfall 40 km south-southeast of the Lockhart River with winds of 130 km/h. At the same time, the JTWC assessed Monica to have intensified into a Category 2 equivalent storm with winds of 155 km/h. Shortly after making landfall, convection associated with the storm deteriorated and the outflow became fragmented. A shortwave trough to the south caused the ridge steering Monica to weaken, leading to the cyclone moving slower. After moving over land, the storm began to weaken, with the Bureau of Meteorology downgrading the storm to weaken to Category 1 cyclone and the JTWC downgraded the cyclone to a tropical storm; the following day, Monica moved offshore. Once back over water, favourable atmospheric conditions allowed the storm to intensify. Within 24-hours of moving over water, Monica re-attained severe tropical cyclone status.

Following a shift in steering currents, the storm slowed and turned north-westward. Steady intensification continued through 22 April as the storm remained in a region of low wind shear and favourable diffluence. Early on 22 April the Bureau of Meteorology upgraded Monica to a Category 5 severe tropical cyclone, the third of the season. By this time, a 37 km wide eye had developed within the central dense overcast of the cyclone; that day, the JTWC assessed Monica to have intensified into a Category 5-equivalent storm. Cyclone Monica attained its peak intensity on 23 April near Cape Wessel with a barometric pressure 916 hPa. Maximum winds were estimated at 250 km/h by the Bureau of Meteorology while the JTWC assessed it to have attained winds of 285 km/h. Using the Dvorak technique, the peak intensity of the cyclone was estimated at T-number of 7.5 according to the Satellite Analysis Branch, yet the Advanced Dvorak Technique of the CIMSS automatically estimated at T8.0, the highest ranking on the Dvorak Scale.

However, since the JTWC, SAB and CIMSS are not the official warning centres for Australian cyclones, these intensities remain unofficial. On 24 April, the mid-level ridge south of M