The Shanghai International Settlement originated from the 1863 merger of the British and American enclaves in Shanghai, in which parts of the Qing Empire would hold extraterritorially under the terms of a series of Unequal Treaties until 1941. The settlements were established following the defeat of the Qing army by the British in the First Opium War. Under the terms of the Treaty of Nanking, the five treaty ports including Shanghai were opened to foreign merchants, overturning the monopoly held by the southern port of Canton under the Canton System; the British established a base on Hong Kong under an extensive lease. American and French involvement followed on the heels of the British and their enclaves were established north and south of the British area. Unlike the colonies of Hong Kong and Macau, where Great Britain and Portugal enjoyed full sovereignty in perpetuity, the foreign concessions in China remained under Chinese sovereignty. In 1854, the three countries created the Shanghai Municipal Council to serve all their interests, but, in 1862, the French concession dropped out of the arrangement.

The following year the British and American settlements formally united to create the Shanghai International Settlement. As more foreign powers entered into treaty relations with China, their nationals became part of the administration of the settlement, but it always remained a predominantly British affair until the growth of Japan's involvement in the late 1930s; the international settlement came to an abrupt end in December 1941 when Japanese troops stormed in following the attack on Pearl Harbor. In early 1943, new treaties signed by Chiang Kai-shek's Republican government formally ended the extraterritorial privileges of Americans and Britons, although its terms were moot until the recovery of Shanghai following Japan's 1945 surrender; the French surrendered their privileges in a separate 1946 agreement. Although Europeans had shown more interest in Canton than Shanghai early on for commercial advantages, the port's strategic position was key to British interests as the island nation declared war against China in 1839 known as the first Anglo-Chinese Opium War.

The first settlement in Shanghai for foreigners was the British settlement, opened in 1843 under the terms of the Treaty of Nanking, one of the many unequal treaties China incurred in opposition to its European trading partners.. The settlement was bordered at north by the right bank of the Suzhou River before it flows into the Huangpu, at east by the Huangpu, at south by a channel, the Yang-King-Pang which will be the future boundary with the French concession. On the orders of Sir Henry Pottinger, first Governor-general of Hong Kong, Captain George Balfour of the East India Company's Madras Artillery arrived as Britain's first consul in Shanghai on 8 November 1843 aboard the steamer Medusa; the next morning Balfour sent word to the circuit intendant of Shanghai, Gong Mujiu, requesting a meeting, at which he indicated his desire to find a house to live in. Balfour was told no such properties were available, but on leaving the meeting, he received an offer from a pro-British Cantonese named Yao to rent a large house within the city walls for four hundred dollars per annum.

Balfour, his interpreter Walter Henry Medhurst, surgeon Dr. Hale and clerk A. F. Strachan moved into the luxuriously furnished 52-room house immediately, it served as the consulate during construction of a Western-style building within the official Settlement boundaries just to the south of Suzhou Creek. This was completed within a year; this soon became the epicenter of the British settlement. Afterward both the French and the Americans signed treaties with China that gave their citizens extraterritorial rights similar to those granted to the British, but their respective nationals accepted that the foreign settlement came under British consular jurisdiction. However, it must be understood that Shanghai has been from the beginning a settlement, not a possession; the British Government annexed Hong Kong, which became British territory, subject to British law. The land on which the Foreign Settlement of Shanghai was created was, on the other hand, only leased to the British Government; that is proved by the fact.

The Sino-American Treaty of Wanghia was signed in July 1844 by Chinese Qing government official Qiying, the Viceroy of Liangguang, who held responsibility for the provinces of Guangdong and Guangxi, Massachusetts politician Caleb Cushing, dispatched with orders to "save the Chinese from the condition of being an exclusive monopoly in the hands of England" as a consequence of the 1842 Nanking treaty. Under the Treaty of Wanghia, Americans gained the same rights as those enjoyed by the British in China's treaty ports, it contained a clause that carved out Shanghai as an extraterritorial zone within Imperial China, though it did not give the American government a true legal concession. It was only in 1845 that Britain followed in America's footsteps and signed a land-deal to allow Britons to rent land in Shanghai in perpetuity; the American consular presence did not create a problem for the British because it was never intended to have a post in person. Since American traders in China were prohibited from engaging in the opium trade, their business transactions were conducted under the auspices of British firms.

The only serious incident of political complaint against the Americans was in 1845, when the Stars and Stripes was raised by the acting US Consul, Henry G. Wolcott, who had just arrived in the

In fluid dynamics, Bickley jet is a steady two-dimensional laminar plane jet with large jet Reynolds number emerging into the fluid at rest, named after W. G. Bickley, who gave the analytical solution in 1937, to the problem derived by Schlichting in 1933 and the corresponding problem in axisymmetric coordinates is called as Schlichting jet; the solution is valid only for distances far away from the jet origin. Consider a steady plane emerging into the same fluid, a type of submerged jets from a narrow slit, supposed to be small. Let the velocity be in Cartesian coordinate and the axis of the jet be x axis with origin at the orifice; the flow is self-similar for large Reynolds number and can be approximated with boundary layer equations. ∂ u ∂ x + ∂ v ∂ y = 0, u ∂ u ∂ x + v ∂ u ∂ y = ν ∂ 2 u ∂ y 2, where ν is the kinematic viscosity and the pressure is everywhere equal to the outside fluid pressure. Since the fluid is at rest far away from the center of the jet u → 0 as y → ± ∞,and because the flow is symmetric about x axis v = 0 at y = 0,and since there is no solid boundary and the pressure is constant, the momentum flux M across any plane normal to the x axis must be the same M = 2 ρ ∫ 0 ∞ u 2 d y is a constant, where ρ which constant for incompressible flow.

The constant momentum flux condition can be obtained by integrating the momentum equation across the jet. ∫ − ∞ ∞ u ∂ u ∂ x d y + ∫ − ∞ ∞ v ∂ u ∂ y d y = − ∞ ∞, d d x ∫ − ∞ ∞ u 2 d y = 0, ⇒ ∫ 0 ∞ u 2 d y = constant. Where v ∂ u / ∂ y = ∂ / ∂ y − u ∂ v / ∂ y = ∂ / ∂ y + u ∂ u / ∂ x is used to simplify the above equation; the mass flux Q across any cross section normal to the x axis is not constant, because there is a slow entrainment of outer fluid into the jet, it's a part of the boundary layer solution. This can be verified by integrating the continuity equation a

Tetrapulmonata is a non-ranked supra-ordinal clade of arachnids. It is composed of the extant orders Thelyphonida, Schizomida and Araneae, it is the only supra-ordinal group of arachnids, supported in molecular phylogenetic studies. Two extinct orders are placed in this clade and Uraraneida. In 2016, a newly described fossil arachnid, was included in the Tetrapulmonata, it receives its name from the presence of paired book lungs occupying the second and third opisthosomal segments, although the posterior pair is absent in Schizomida and most araneomorph spiders. Previous synonyms of this lineage are rejected; the clade is referred to as Pantetrapulmonata. The name "Pulmonata" has been used for this group as as 2000, in the first paragraph of an article in Journal of Paleontology, but this creates an ambiguity because Pulmonata is a group of gastropods. In addition to the two pairs of book lungs, other synapomorphies of Tetrapulmonata include a large postcerebral pharynx, prosomal endosternite with four segmental components, subchelate chelicerae, a complex coxotrochanteral joint in the walking legs, a pretarsal depressor muscle arising in the patella, a pedicel formed, in part, by ventral elements of the second opisthomal segment and a spermatozoon axoneme with a 9+3 microtubule arrangement.

A cladogram published in 2014 divides the Tetrapulmonata into two clades, the Schizotarsata and the Serikodiastida. The Schizotarsata have walking legs II–IV with the tarsus having a specific pattern of three subsegments; the Serikodiastida share the ability to use silk. The sister clade to Tetrapulmonata is the extinct order Trigonotarbida. In 2016, a fossil arachnid from the Late Carboniferous age was described in the genus Idmonarachne. Based on its overall morphology, it was considered to belong to the Serikodiastida, although the presence of silk-producing spigots was not demonstrated. Like uraraneids, it lacked spinnerets, but it lacked a flagellum, thus resembling spiders. A cladogram based on morphology placed Idmonarachne between uraraneids and spiders: The Late Carboniferous appears to be a time when there was a greater diversity of tetrapulmonate arachnids. Jeffrey W. Shultz. 2007. "A phylogenetic analysis of the arachnid orders based on morphological characters". Zoological Journal of the Linnean Society 150:221-265..

Shultz on arachnid morphology At: Index of /mndi/Aracnologia At: Museu Nacional / UFRJ / Departamento de Invertebrados At: Museu Nacional / UFRJ