Environmental analysis Essay Example | Topics and Well Written Essays - 250 words

Environmental analysis - Essay Example The rates used to charges in maintain and securing a website should be reduced and some information limited for the benefit of the hotels in Australia. Increasing overseas arrivals as threats result to struggling of negligible number of customers worldwide, a factor that leads to reduction of market share. Overseas countries offer cheap and incredible hotel services with the intention of scrambling for customers globally; hence, increasing competition. (Todd & Organization for Economic Co-operation and Development, 2008). The international organization in charge of hotels should endorse fair competition by setting a standard price for services offered in hotels globally. The policy will limit the chances of hotels offering extremely lower prices, which spoils business for other hotels globally, especially Australia. High GDP in Australia affects hotel industry negatively since the hotels have to pay additional taxes to the government to raise the capital to pay the debts (Faeth, 2010). Consequently, the annual income for the hotels is reduced by a big percentage exceptionally. Australia government should maintain high economic levels and avoid having debts that by ensuring that pay according to the initial agreement. This reduces the chances of hotels paying extra taxes to raise money for debts. High exchange rate frightens potential investors interested in Hotel industry. It is expensive to invest in the business, for example, constructing of international hotels in the country. Moreover, clients, especially visitors, find travelling costly because of the expensive fare. Domestic clients are forced to seek cheap services oversees. High exchange rate has caused unemployment and limitation in getting sufficient services from hotels, which are supposed to satisfy them (Sharma, 2005). Australia’s government should trade their dollar attractively to draw international

Positron Annihilation Essay Example | Topics and Well Written Essays - 2500 words

Positron Annihilation - Essay Example The gamma rays released can be detected and measured. A source of positrons and a detector for gamma radiation is required to study positron annihilation. The positron annihilation experiment involves the use of two detectors placed at an angle anywhere between 160-200Â °. 22Na and 60Co are used in the experiment. The scintillation detectors are used not only for the detection but also measurement of gamma radiation. Electronic counters are used for investigating the annihilation events. The observations made regarding the annihilation events in case of 22Na were found to be in agreement with theoretical considerations. The angular distribution of gamma rays from a 60Co source was also investigated. This part of the experiment provided rather convoluted information. The gamma rays resulting from annihilation events were found to be more spread rather than peaked. Such a behavior can be attributed to the changes in the angular momentum of the 60Co nucleus as it progresses through its unstable, excited state. Observations made in this experiment are in agreement with theoretical observations. The experiment demonstrates back-to-back emission of annihilation photons, peaking at 180Â °. The coincidence events for 22Na were found to be more reliable than for 60Co. Introduction. Collision of a low energy positron by an electron of low energy results in their annihilation, causing the production of gamma ray photons. They are responsible for carrying away the momentum and energy of the pair. e? + e+ > ? + ? These photon rays do not have enough mass and energy to result in the production of heavier particles. The process of positron annihilation satisfies certain laws of conservation such as the conservation of electric charge, conservation of total energy, and conservation of momentum (both linear and angular). The conservation of linear momentum and energy does not accommodate the creation of one photon but rather two gamma rays. The two gamma rays ensuing from the positron annihilation move in the opposite direction. The energy possessed by these two gamma rays is approximately 0.511 MeV (Mega electron Volts). Figure 1: Feynman diagram of positron annihilation (Booklet, 2012) The two gamma rays are created because there is no momentum in the system during annihilation as both the electron and the positron come to rest for a short moment. The momentum of the system cannot be conserved if only one proton is created in the process. The collective amount of 1.022 MeV energy of the two gamma rays that are moving in opposite directions satisfies the conservation of the momentum and energy. The positron used in the annihilation process is often obtained from the decay of a proton into a neutron, resulting in the release of a positron and a neutrino. Figure 2: Emission of positron and its annihilation (PET, 2007) The gamma rays released in the process of positron annihilation are both detectable and measurable. Time coincidence counting is a technique that is employed for studying radioactive materials. With this technique, radioactive materials can be detected and identified. The disintegration rates of the radioactive materials can also be calibrated with this technique. The absolute activity of the materials can be measured by counting th e radiation events occurring in the radioactive material. The radiation could comprise of beta and gamma rays and can be easily measured using the technique. During the decay of an unstable nucleus, several photons may be emitted in a cascade. 60Co nucleus is one such example. In 22Na, the decay product, which is a positron, annihilates in the source itself. To induce positron annihilation or study it, there is a need for a positron emitter. Various materials have been used