F-4 Phantom II in the Vietnam War

F-4 Phantom II in the Vietnam War In 1952, McDonnell Aircraft began internal studies to determine which service branch was most in need of a new aircraft. Led by Preliminary Design Manager Dave Lewis, the team found that the US Navy would soon require a new attack aircraft to replace the F3H Demon. The designer of the Demon, McDonnell began revising the aircraft in 1953, with the goal of improving performance and capabilities. Creating the Superdemon, which could achieve Mach 1.97 and was powered by twin General Electric J79 engines, McDonnell also created an aircraft that was modular in that different cockpits and nose cones could be affixed to the fuselage depending on desired mission. The US Navy was intrigued by this concept and requested a full-scale mock-up of the design. Assessing the design, it ultimately passed as it was satisfied with the supersonic fighters already in development such as the Grumman F-11 Tiger and Vought F-8 Crusader.  Ã‚   Design Development Altering the design to make the new aircraft an all-weather fighter-bomber featuring 11 external hardpoints, McDonnell received a letter of intent for two prototypes, designated YAH-1, on October 18, 1954. Meeting with the US Navy the following May, McDonnell was handed a new set of requirements calling for an all-weather fleet interceptor as the service had aircraft to fulfill the fighter and strike roles. Setting to work, McDonnell developed the XF4H-1 design. Powered by two J79-GE-8 engines, the new aircraft saw the addition of a second crewman to serve as a radar operator. In laying out the XF4H-1, McDonnell placed the engines low in the fuselage similar to its earlier F-101 Voodoo and employed variable geometry ramps in the intakes to regulate airflow at supersonic speeds. Following extensive wind tunnel testing, the outer sections of the wings were given  12 ° dihedral (upward angle) and the tailplane  23 ° anhedral (downward angle). Additionally, a dogtooth indentation was inserted in the wings to enhance control at higher angles of attack. The results of these alterations gave the XF4H-1 a distinctive look. Utilizing titanium in the airframe, the XF4H-1s all-weather capability was derived from the inclusion of the AN/APQ-50 radar. As the new aircraft was intended as an interceptor rather than a fighter, early models possessed nine external hardpoints for missiles and bombs, but no gun. Dubbed the Phantom II, the US Navy ordered two XF4H-1 test aircraft and five YF4H-1 pre-production fighters in July 1955. Taking Flight On May 27, 1958, the type made its maiden flight with Robert C. Little at the controls. Later that year, the XF4H-1 entered into competition with the single-seat Vought XF8U-3. An evolution of the F-8 Crusader, the Vought entry was defeated by the XF4H-1 as the US Navy preferred the latters performance and that the workload was split between two crew members. After additional testing, the F-4 entered production and commenced  carrier suitability trials in early 1960. Early in production, the aircrafts radar was upgraded to the more powerful  Westinghouse AN/APQ-72. Specifications (F-4E Phantom II) General Length: 63 ft.Wingspan: 38 ft. 4.5 in.Height: 16 ft. 6 in.Wing Area: 530 sq. ft.Empty Weight: 30,328 lbs.Loaded Weight: 41,500 lbs.Crew: 2 Performance Power Plant: 2 Ãâ€" General Electric J79-GE-17A axial compressor turbojetsCombat Radius: 367 nautical milesMax. Speed: 1,472 mph (Mach 2.23)Ceiling: 60,000 ft. Armament 1 x M61 Vulcan 20 mm Gatling cannonUp to 18,650 lbs. of weapons on nine external hardpoints, including air-to-air missiles, air-to-ground missiles, and most types of bombs Operational History Setting several aviation records just prior to and in the years after introduction, the F-4 became operational on December 30, 1960, with VF-121. As the US Navy transitioned to the aircraft in the early 1960s, Secretary of Defense Robert McNamara pushed to create a single fighter for all branches of the military. Following an F-4Bs victory over the F-106 Delta Dart in Operation Highspeed, the US Air Force requested two of the aircraft, dubbing them the F-110A Spectre. Evaluating the aircraft, the USAF developed requirements for their own version with an emphasis on the fighter-bomber role. Vietnam Adopted by the USAF in 1963, their initial variant was dubbed the F-4C. With the US entry in the Vietnam War, the F-4 became one of the most identifiable aircraft of the conflict. US Navy F-4s flew their first combat sortie as part of Operation Pierce Arrow on August 5, 1964. The F-4s first air-to-air victory occurred the following April when Lieutenant (j.g.) Terence M. Murphy and his radar intercept officer, Ensign Ronald Fegan, downed a Chinese MiG-17. Flying primarily in the fighter/interceptor role, US Navy F-4s downed 40 enemy aircraft to a loss of five of their own. An additional 66 were lost to missiles and ground fire. Also flown by the US Marine Corps, the F-4 saw service from both carriers and land bases during the conflict. Flying ground support missions, USMC F-4s claimed three kills while losing 75 aircraft, mostly to ground fire. Though the latest adopter of the F-4, the USAF became its largest user. During Vietnam, USAF F-4s fulfilled both air superiority and ground support roles. As F-105 Thunderchief losses grew, the F-4 carried more and more of the ground support burden and by the end of the war was the USAFs primary all-around aircraft. To support this change in mission, specially equipped and trained F-4 Wild Weasel squadrons were formed with the first deploying in late 1972. In addition, a photo reconnaissance variant, the RF-4C, was used by four squadrons. During the Vietnam War, the USAF lost a total of 528 F-4s (of all types) to enemy action with the majority being down by anti-aircraft fire or surface-to-air missiles. In exchange, USAF F-4s downed 107.5 enemy aircraft. The five aviators (2 US Navy, 3 USAF) credited with ace status during the Vietnam War all flew the F-4. Changing Missions Following Vietnam, the F-4 remained the principal aircraft for both the US Navy and USAF. Through the 1970s, the US Navy began replacing the F-4 with the new F-14 Tomcat. By 1986, all F-4s had been retired from frontline units. The aircraft remained in service with the USMC until 1992, when the last airframe was replaced by the F/A-18 Hornet. Through the 1970s and 1980s, the USAF transitioned to the F-15 Eagle and F-16 Fighting Falcon. During this time, the F-4 was retained in its Wild Weasel and reconnaissance role. These two latter types, the F-4G Wild Weasel V and RF-4C, deployed to the Middle East in 1990, as part of Operation Desert Shield/Storm. During operations, the F-4G played a key role in suppressing Iraqi air defenses, while the RF-4C collected valuable intelligence. One of each type was lost during the conflict, one to damage from ground fire and the other to an accident. The final USAF F-4 was retired in 1996, however several are still in use as target drones. Issues As the F-4 was initially intended as an interceptor, it was not equipped with a gun as planners believed that air-to-air combat at supersonic speeds would be fought exclusively with missiles. The fighting over Vietnam soon showed that engagements quickly became subsonic, turning battles which often precluded the use of air-to-air missiles. In 1967, USAF pilots began mounting external gunpods on their aircraft, however the lack of a leading gunsight in the cockpit made them highly inaccurate. This issue was addressed with the addition of an integrated 20 mm M61 Vulcan gun to the F-4E model in the late 1960s. Another problem that frequently arose with the aircraft was the production of black smoke when the engines were run at military power. This smoke trail made the aircraft easy to spot. Many pilots found ways to avoid producing the smoke by running one engine on afterburner and the other at reduced power. This provided an equivalent amount of thrust, without the telltale smoke trail. This issue was addressed with the Block 53 group of the F-4E which included smokeless J79-GE-17C (or -17E) engines. Other Users The second-most produced Western jet fighter in history with 5,195 units, the F-4 was extensively exported. Nations that have flown the aircraft include Israel, Great Britain, Australia, and Spain. While many have since retired the F-4, the aircraft has been modernized and is still use (as of 2008) by Japan, Germany, Turkey, Greece, Egypt, Iran, and South Korea.

Should the Ruler Always Keep His Word Essay Example | Topics and Well Written Essays - 2250 words

Should the Ruler Always Keep His Word - Essay Example It is possible to present power from an unusual perspective. This task was the most relevant to Machiavelli and he managed to open the eyes of his fans and follower and the coming generations on the real essence of power, and on power of the words. In the majority of cases Princes are focused on their own interests. They are selfish and prudent; they do not care about their people at all. Machiavelli has been focused on the relevance of the ruler and the meaning of his word. Further on this paper considers controversial and challenging moments of the statement that a ruler should not keep his word. A word of a ruler Machiavelli inspires readers. They love him for sincerity, unexpected expressions, feelings and emotions. Machiavelli claims: â€Å"One ought not, of course, to call it  virtu  to massacre one’s fellow citizens, to betray one’s friends, to break one’s word, to be without mercy and without religion. By such means one can acquire power but not glor y† (Prince online). Nowadays, the majority of politicians are focused on power. They consider it as an enormous blessing and there is no doubt that even the modern politicians cannot look further than their nose. Machiavelli and his feeling of patriotism, multiplied by a possibility to exist among other politicians and clerk were the main triggers for further developments of his political ideas. Actually, Machiavelli described people as masters and slaves. A former group of people is more powerful and it is appropriate for them to take care about themselves only. Slaves, or common people, in accordance with Machiavelli, are narrow-minded and follow the laws of the ruler, like an obedient herd of ships (Bagley, 1989). Therefore, it is possible to suggest, that Machiavelli wants to describe a dual nature of a human being. There are two origins in the nature of every man: on the one hand, we choose: "What [classical writers] intended to convey, with this story of rulers’ b eing educated by someone who was half beast and half man, was that it is necessary for a ruler to know when to act like an animal and when like a man; and if he relies on just one or the other mode of behavior he cannot hope to survive" (Prince online). This explanation can be correlated with a developed system of people, i.e. Masters and Slaves (Alter, 1999). Masters know how to behave with their slaves; they impose perverted laws on them and they have no doubts that their Slaves would follow all their needs and wants. When it goes about Masters’ words or the ways of behavior, they have sharp minds and can easily choose appropriate strategies and the ways of behavior. A Master uses beasty features, turns into a lion and can easily conquer his enemies. A Master turns into a fox, when he wants to conduct his cunning laws and create traps for his Slaves. On the one hand, it is appropriate for a ruler to choose different strategies of behavior. Otherwise it is impossible to reig n. On the other hand, what can be said about a ruler if he does not keep his word? He can lose respect and trust of his people. Only a feeling of fear can prevent people from real protesting. In this case, the Prince can behave in whatever he wants, because he will get no resistance from people around him. There are many things, which are permitted for the king, but these deeds are forbidden for a slave. Machiavelli claims that there are many sins and every man

Nepotism Essay Example | Topics and Well Written Essays - 2000 words

Nepotism - Essay Example There are several concepts that should be engaged in the analysis while considering the nature of nepotism. To begin with, it would not be an exaggeration to suggest that the notion of integrity is something that is heavily damaged by the issue in question (McNamee, 2004, p. 87). Indeed, granting positions or preferences to family member can hardly be compatible with integrity of an organization. The next concept that is of great important when it comes to a fair examination of it is the idea of competition. As it has already been noted, people have to fight for their success and should be rewarded accordingly. The practice of nepotism grants a person an advantage that ruins the entire system of competition in the society and does not allow people to advance. Finally, the concept of meritocracy is something that should also be engaged while considering the impact that nepotism has on the society. It certainly would be an ideal situation when people are rewarded according to their mer its, but it is something that the social environment should be moving forward to; however, the practice of nepotism just makes this state of affairs unrealistic and reinforces the inequality among the people. In other words, the very existence of it does not allow the society evolve properly. That is why nepotism might be seen as a direct result of the inertia that has been guiding the process of development of the society for a considerable time. Nevertheless, it is quite obvious that is this practice is not taken care of, it will lead to a dead end. Keeping in mind that people will never want to stop evolution of their civilization, there is no other way but to deal with nepotism. That is why nepotism might be seen as a direct result of the inertia that has been guiding the process of development of the society for a considerable time. Nevertheless, it is quite

Diversity in the Work Place Research Paper Example | Topics and Well Written Essays - 1250 words

Diversity in the Work Place - Research Paper Example The workplace diversity is developed based on the principles of EEO (Equal Employment Opportunity). It focuses on ensuring the fact that all the employees should have an equal access to the employment opportunities and conditions. Diversity means acceptance and valuing of these differences which are inherent in each and every individual and recognition of the contribution where a diverse workforce will enhance the performance and effectiveness of the organizations. The key aspect of such workplace diversity is the contribution which is made to the organization in order to set it free from all the discriminations and harassments. Challenges in the workplace diversity Some of the challenges which concern the workplace diversity process are Cultural and language barriers The cultural and language barriers are needed to be overcome for the diversity programs to be successful. Ineffective communication might result in the lack of a proper teamwork within the organization (D'Almeida, 2007) . Resistance to change Sometimes the employees refuse to accept and adapt to changes in the cultural and social environment in their workplace. This results in a resistance to fast progress of the organization. IBM The company which has been chosen for understanding the workplace diversity and its importance within an organization is IBM. International Business Machine Corporation is one of the American multinational corporations. It’s headquarter is located in Armonk, New York. The company manufactures as well as markets computer hardware and software and also offers other services like hosting, consulting etc. in various areas ranging from the mainframe computers to the nanotechnology (IBM, 2013). It is presently employing 434,246 employees (IBM, 2012). The company was established in the year 1911 on the merger of three big companies i.e. Tabulating Machine Company, the Computing Scale Company and the International Time Recording Company (The Atlantic, 2013; IBM, 2007). IBM : Views Regarding Workplace Diversity In order to remain competitive, IBM believes that it needs an employee population which understands the markets where the company serves its products and services (IBM, 2008). The company requires an employee population uniting all the different cultures, professions, perspectives, geographical origin etc. into one global integrated enterprise (IBM, 2010). The goal of the company is an enhancement of open-mindedness, awareness, knowledge, and respect for other cultures for building a stronger working team which can foster innovation. The diversity in IBM signifies that the difference is always expected, valued and encouraged within the organization so that each and every employee can be innovative, productive and achieve full potential. The mission of the company is creating such a culture, environment and climate where the talents from various regions would be valued and maximized by the utilization of this diverse talent in various fields whic h would result in the achievement of success for the corporation.

Calculations of the Spin Structure of Trimer Cr3

Calculations of the Spin Structure of Trimer Cr3 Calculation of Magnetic Properties by Generalized Spin Hamiltonian and Generation  of Global Entanglement: Cr Trimer in molecule and on surface Oleg V. Stepanyuk2, Oleg V. Farberovich1 1 Raymond and Bekerly Sackler Faculty of Exact Sciences,  School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978, Israel 2 Max Planck Institute of Microstructure Physics, Halle, Germany Here we present the results of the first-principles calculations of the spin structure of trimer Cr3  with the use of a density-functional scheme allowing for the non-collinear spin configurations in  [1]. Using the results of these calculations we determine the Heisenberg-Dirac-Van Vleck (HDVV)  Hamiltonian with anisotropic exchange couplings parameters linking the Cr ions with predominant  spin density. The energy pattern was found from the effective HDVV Hamiltonian acting in the  restricted spin space of the Cr ions by the application of the irreducible tensor operators (ITO)   technique. Comparison of the energy pattern with that obtained with the anisotropic exchange  models conventionally used for the analysis of this system and with the results of non-collinear  spin structure calculations show that our complex investigations provides a good description of the  pattern of the spin levels and spin structures of the nanomagnetic trimer Cr3. The results are   discussed in the view of a general problem of spin frustration related to the orbital degeneracy of  the antiferromagnetic ground state.   PACS numbers: I. INTRODUCTION Information technologies provide very interesting challenges  and an extremely wide playground in which scientists  working in materials science, chemistry, physics and  nano-fabrication technologies may find stimuli for novel  ideas. Curiously, the nanometre scale is the molecular  scale. So we may wonder whether, how or simply which  functional molecules can be regarded in some ways as  possible components of nanodevices. The goal is ambitious: it is not just a matter to store information in a 3dmetal  trimer on a non-magnetic substrate, but we may  think to process information with a trimer and then to  communicate information at the supramolecules containg  from magnetic 3d-metal trimer on a surface. Spins are alternative complementary to charges as degrees  of freedom to encode information. Recent examples,  like for instance the discovery and application of Giant  magnetoresistance in Spintronics, have demonstrated  the efficient use of spins for information technologies. Moreover, spins are intrinsically quantum entities and  they have therefore been widely investigated in the field  of quantum-information processing. Molecular nanomagnets  are real examples of finite spin chains (1D) or clusters  (0D), and therefore they constitute a new benchmark  for testing models of interacting quantum objects. New physics of molecular magnets feeds hopes of certain  prospective applications, and such hopes pose the  problem of understanding, improving, or predicting desirable  characteristics of these materials. The applications  which come into discussion are, for instance, magnetic  storage (one molecule would store one bit, with  much higher information storage density than accessible  with microdomains of present-day storage media or magnetic  nanoparticles of next future). In order to exploit  the quantum features for information processing, molecular  spin clusters have to fulfil some basic requirements. Magnetic transition metal nanostructures on nonmagnetic  substrates have attracted recently large attention  due to their novel and unusual magnetic properties[2,3]. The supported clusters experience both the  reduction of the local coordination number, as in free  clusters, as well as the interactions with the electronic  degrees of freedom of the substrate, as in embedded clusters.   The complex magnetic behavior is usually associated  with the competition of several interactions, such  as interatomic exchange and bonding interactions, and  in some cases noncollinear effects, which can give rise to  several metastable states close in energy. The ground  state can therefore be easily tuned by external action  giving rise to the switching between different states. In recent years, entanglement has attracted the attention  of many physicists working in the area of quantum  mechanics [1, 2]. This is due to the ongoing research in  the area of quantum information [3]. Theoretical studies  are also important in the context of spin interactions  inside two structured reservoirs [9] such as single magnetic  molecule (SMM) and metal cluster on nonmagnetic  surface. Cr is unique among the transition-metal  adatoms, because its half-filled valence configuration  (3d54s1) yields both a large magnetic moment and strong  interatomic bonding leading to magnetic frustration. We  apply our method to Cr trimers deposited on a Au(111)  surface and the trinuclear hydroxo-bridged chromium  ammine complex [Cr3(NH3)10(OH)4]Br5  · 3H2O. Low-lying excited states of a magnetic system are generally  described in terms of a general spin-Hamiltonian. For a magnetic system with many spin sites, this phenomenological  Hamiltonian is written as a sum of pairwise  spin exchange interactions between adjacent spin  sites in molecule and surface. In the present work we study entanglement between  the spin states in the spin spectrum. In our model, a  spin state interact with a continuum of the spin structure  at interval temperature 0 – 300 K, and entanglement  properties between the spin states in spin structure are  considered. Using global entanglement as a measure of  entanglement, we derive a pair of distributions that can  be interpreted as densities of entanglement in terms of  all the eigenvalue of the spin spectrum. This distribution  can be calculated in terms of the spectrum of spin excitation  of cluster surface and supramolecule. With these  new measures of entanglement we can study in detail  entanglement between the spin modes in spin structure. The method developed here, in terms of entanglement  distributions, can also be used when considering various  types of structured reservoirs [..]. II. THE THEORETICAL APPROACH In order to give a theoretical description of magnetic  dimer we exploit the irreducible tensor operator (ITO)  technique [ITO]. Let us consider a spin cluster of arbitrary  topology formed from an arbitrary number of magnetic  sites, N, with local spins S1, S2,, SN which, in  general, can have different values. A successive spin coupling  scheme is adopted: S1 + S2 = SËÅ"2, SËÅ"2 + S3 = SËÅ"3, , SNËÅ"à ´Ã¢â€š ¬Ã¢â€š ¬Ã¢â€š ¬1 + SN = S, where ËÅ" S represents the complete set of intermediate spin  quantum numbers SËÅ"k, with k=1,2,,N-1.The eigenstates  | và ¢Ã… ¸Ã‚ © of spin-Hamiltonian will be given by linear combinations  of the basis states | ( ËÅ" S)SMà ¢Ã… ¸Ã‚ ©: | và ¢Ã… ¸Ã‚ © = ÃŽ £ (~S )SM à ¢Ã… ¸Ã‚ ¨(~S )SM | và ¢Ã… ¸Ã‚ © | (~S )SMà ¢Ã… ¸Ã‚ ©, (1) where the coefficients à ¢Ã… ¸Ã‚ ¨( ËÅ" S)SM | và ¢Ã… ¸Ã‚ © can be evaluated once  the spin-Hamiltonian of the system has been diagonalized. Since each term of spin-Hamiltonian can be rewritten  as a combination of the irreducible tensor operators  technique[ITO].In [ITO] work focus on the main physical  interactions which determine the spin-Hamiltonian and  to rewrite them in terms of the ITO’s. The exchange  part of the spin-Hamiltonian is to introduced: Hspin = H0 + HBQ + HAS + HAN. (2) The first term H0 is the Heisenberg-Dirac Hamiltonian,  which represents the isotropic exchange interaction, HBQ  is the biquadratic exchange Hamiltonian, HAS is the antisymmetric  exchange Hamiltonian,and HAN represents  the anisotropic exchange interaction. Conventionally,  they can be expressed as follows [ITO]: H0 = −2 ÃŽ £ i;f Jif bSi bSf (3) HBQ = − ÃŽ £ i;f jif ( bSi bSf )2 (4) HAS = ÃŽ £ i;f Gif [ bSi Ãâ€" bSf ] (5) HAN = −2 ÃŽ £ i;f ÃŽ £ _ J_ if bS_ i bS_ f (6) with ÃŽ ± = x, y, z We can add to the exchange Hamiltonian  the term due to the axial single-ion anisotropy: HZF = ÃŽ £ i Di bSz(i)2 (7) where Jif and J_   if are the parameters of the isotropic and  anisotropic exchange iterations, jif are the coefficients of  the biquadratic exchange iterations,and Gif=-Gfi is the  vector of the antisymmetric exchange. The terms of the  spin-Hamiltonian above can be written in terms of the  ITO’s. Both the Heisenberg–Dirac and biquadratic exchange  are isotropic interactions. In fact, the corresponding  Hamiltonians can be described by rank-0 tensor operators  and thus have non zero matrix elements only  with states with the same total spin quantum number  S (ΔS,ΔM=0). The representative matrix can be decomposed  into blocks depending only on the value of S  and M. All anisotropic terms are described by rank-2  tensor operators which have non zero matrix elements  between state with ΔS=0, ±1, ±2 and their matrices can  not be decomposed into blocks depending only on total  spin S in account of the S–mixing between spin states  with different S. The single-ion anisotropy can be written  in terms of rank-2 single site ITO’s [ITO]. Finally,  the antisymmetric exchange term is the sum of ITO’s of  rank-1. The ITO technique has been used to design the MAGPACK  software [ITO1], a package to calculate the energy  levels, bulk magnetic properties, and inelastic neutron  scattering spectra of high nuclearity spin clusters that  allows studying efficiently properties of nanoscopic magnets. A. Calculation of the magnetic properties Once we have the energy levels, we can evaluate different  thermodynamic properties of the system as magnetization,  magnetic susceptibility, and magnetic specific  heat. Because anisotropic interactions are not included,  the magnetic properties of the anisotropic system do not  depend on the direction of the magnetic field. For this  reason one can consider the magnetic field directed along  arbitrary axis Z of the molecular coordinate frame that  is chosen as a spin quantization axis. In this case the  energies of the system will be à Ã‚ µ_(Ms)+geÃŽ ²MsHZ, where  Ãƒ Ã‚ µ_(Ms) are the eigenvalues of the Hamiltonian containing  magnetic exchange and double exchange contributions  (index ÃŽ ¼ runs over the energy levels with given total  spin protection Ms). Then the partition function in the  presence of the external magnetic field is given by: Z(HZ) = ÃŽ £ Ms;_ exp[−à Ã‚ µ_(Ms)/kT] ÃŽ £ Ms exp[−geÃŽ ²MsHZ/kT] (8) Using this expression one can evaluate the magnetic susceptibility  Ãâ€¡ and magnetization M by standart thermodinamical  definitions: χ = ( ∂M ∂H ) H!0 (9) M(H) = NkT ∂lnZ ∂H (10) B. Entanglement in N-spin system Entanglement has gained renewed interest with the development  of quantum information science. The problem  of measuring entanglement is a vast and lively field of research  in its own. In this section we attempt to solve the  problem of measuring entanglement in the N-spin cluster  and supramolecules systems. Based on the residual  entanglement [9] (Phys. Rev. A 71, 044301 (2005)), we  present the global entanglement for a N-spin state for the  collective measures of multiparticle entanglement. This  measures introduced by Meyer andWallach[..]. The MeyerWallach  (MW) measure written in the Brennen form (G.K.Brennen,Quantum.Inf.Comp.,v.3,619 (2003)) is: Q(ψ) = 2(1 − 1 N ÃŽ £N k=1 Tr[Ï 2 k]) (11) where Ï k is the reduced density matrix for k-th qubit.   The problem of entanglement between a spin states in  N-spin systems is becoming more interesting when considering  clusters or molecules with a spectral gap in their  densities of states. For quantifying the distribution of  entanglement between the individual spin eigenvalues in  spin structure of N-spin system we use the density of entanglement. The density of entanglement ÃŽ µ(à Ã‚ µ_, à Ã‚ µ_, à Ã‚ µ)dà Ã‚ µ gives the entanglement between the spin eigenvalue à Ã‚ µ_ and spin eigenvalue à Ã‚ µ_ with in an energy interval à Ã‚ µ_ to à Ã‚ µ_ + dà Ã‚ µ_. One can show that entanglement distribution can be  written in terms of spectrum of spin exitation S(à Ã‚ µ_, à Ã‚ µ) = |c_|2 ÃŽ ´(à Ã‚ µ − à Ã‚ µ_) (12) and ÃŽ µ(à Ã‚ µ_, à Ã‚ µ_, à Ã‚ µ) = 2S(à Ã‚ µ_, à Ã‚ µ)S(à Ã‚ µ_, à Ã‚ µ) (13) where coefficient c_ = à ¢Ã… ¸Ã‚ ¨( ËÅ" S)SM | và ¢Ã… ¸Ã‚ © is eigenvector of the  spin-Hamiltonian of the cluster or supramolecule. Thus,  entanglement distributions can be derived from the excitation  spin spectrum Q(à Ã‚ µ) = 1− 2Δ2 Ï€2N ÃŽ £N _=1 |c_|2 (à Ã‚ µ − à Ã‚ µ_)2 + Δ2 ÃŽ £N _=_+1 |c_|2 (à Ã‚ µ − à Ã‚ µ_)2 + Δ2 (14) Though the very nature of entanglement is purely  quantum mechanical, we saw that it can persist for  macroscopic systems and will survive even in the thermodynamical  limit. In this section we discuss how it  behaves at finite temperature of thermal entanglement. The states in N-spin system describing a system in thermal  equilibrium states, are determined by the Generalized  spin-Hamiltonian and thermal density matrix Ï (T) = exp(−Hspin/kT) Z(HZ) (15) where Z(HZ) is the partition function of the N-spin system. The thermal entanglement is Q(à Ã‚ µ, T,HZ) = 1 − 2Δ2 Ï€2NZ(HZ)2 ÃŽ £N _=1 |c_|2 exp[−à Ã‚ µ_/kT] (à Ã‚ µ − à Ã‚ µ_)2 + Δ2 Ãâ€" (16) ÃŽ £N _=_+1 |c_|2 exp[−à Ã‚ µ_/kT] (à Ã‚ µ − à Ã‚ µ_)2 + Δ2 The demonstration of quantum entanglement, however,  can also be directly derived from experiments, without  requiring knowledge of the system state. This can be  done by using specific operators–the so-called entanglement  witnesses–whose expectation value is always positive  if the state Ï  is factorizable. It is quite remarkable  that some of these entanglement witnesses coincide  with well-known magnetic observables, such as energy  or magnetic susceptibility χ = dM/dB. In particular,  the magnetic susceptibility of N spins s, averaged over  three orthogonal spatial directions, is always larger than  a threshold value if their equilibrium state Ï  is factorizable: ÃŽ £ g χg > Ns/kBT [EW]. This should not be surprising,  since magnetic susceptibility is proportional to  the variance of the magnetization, and thus it may actually  quantify spin.spin correlation. The advantage in  the use of this criterion consists in the fact that it does  not require knowledge of the system Hamiltonian, provided  that this commutes with the Zeeman terms corresponding  to the three orthogonal orientations of the  magnetic field ÃŽ ± = x, y, z. As already mentioned, in  the case of the Cr3 trimer, the effective Hamiltonian includes,  besides the dominant Heisenberg interaction J ∠¼118 meV , smaller anisotropic terms G ∠¼ 1.1 meV and  D ∠¼ 0.18 meV , due to which the above commutation relations  are not fulfilled. This might, in principle, result in  differences between the magnetic susceptibility and the  entanglement witness WE (see Fig.). Apparently, the  difference is quite essential and therefore it is necessary to use a formula for global entanglement Q(ψ) in N-spin  system. 4 10−1 100 101 102 103 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 The calculated difference à ¯Ã¢â‚¬Å¡Ã‚ ½EW(T)−EWa(T)à ¯Ã¢â‚¬Å¡Ã‚ ½/EW(T)for Cr3 isosceles trimer T(K) à ¯Ã¢â‚¬Å¡Ã‚ ½EW(T)−EWa(T)à ¯Ã¢â‚¬Å¡Ã‚ ½/EW(T) FIG. 1: (Color online) The calculated difference j EW(T) à ´Ã¢â€š ¬Ã¢â€š ¬Ã¢â€š ¬ EWa(T) j =EW(T) for Cr3 isosceles trimer 0 100 200 300 400 0 2 4 6 0 0.2 0.4 0.6 0.8 1 1.2 Angle(Degrees) The calculated M(H) for Cr3 isosceles trimer H(T) M(à ¯Ã†â€™Ã‚ ¬B) FIG. 2: (Color online)Magnetization M(H) of the Cr3  isoscales trimer on metal surface as a function of angles from 0 to 360 degree C. Thermal global entanglement in static magnetic _eld 5 0 50 100 150 200 250 300 350 400 0 0.05 0.1 0.15 0.2 0.25 The calculated variation of M(H) vs angle (magnetization switching) Angle(Degrees) M(à ¯Ã†â€™Ã‚ ¬B) 0.1Ts 0.2Ts 0.5Ts 1.0Ts FIG. 3: (Color online)The calculated variation of M(H) vs  angle (magnetization switching) for Cr3 isoscales trimer   FIG. 4: (Color online)The calculated density of global entanglement  vs temperature and energy for Cr3 isoscales trimer 6 0 100 200 300 400 0 2 4 6 0 0.5 1 1.5 2 2.5 Angle(Degrees) The calculated M(H) for Cr3 molecular magnet H(T) M(à ¯Ã†â€™Ã‚ ¬B) FIG. 5: (Color online)Magnetization M(H) of the Cr3 molecular  magnet as a function of angles from 0 to 360 degree 0 50 100 150 200 250 300 350 400 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 The calculated variation of M(H) vs angle (magnetization switching) Angle(Degrees) M(à ¯Ã†â€™Ã‚ ¬B) 0.1Ts 0.2Ts 0.5Ts 1.0Ts FIG. 6: (Color online)The calculated variation of M(H) vs  angle (magnetization switching) for Cr3 molecular magnet 7 FIG. 7: (Color online)The calculated density of global entanglement  vs temperature and energy for Cr3 molecular magnet  FIG. 8: (Color online)The calculated entanglement for the  Cr3 isoscales trimer as a function of temperature and the  magnitude of the magnetic field Hpar. 8 FIG. 9: (Color online)The calculated entanglement for the  Cr3 isoscales trimer as a function of temperature and the  magnitude of the magnetic field Hper. FIG. 10: (Color online)The calculated entanglement for the  Cr3 isoscales trimer as a function of temperature and the magnitude  of the magnetic field Hav. 9 FIG. 11: (Color online)The calculated entanglement for the  Cr3 molecular magnet as a function of temperature and the  magnitude of the magnetic field Hav.

Discuss any 3 functions of operating systems.(9 marks)2. Discuss any 3 :: Computer Science

Discuss any 3 functions of operating systems.(9 marks)2. Discuss any 3 factors affecting the choice of an operating systems.(9 marks)3. Discuss the following types of operating systems.„à  Multi tasking Assignment 9 1. Discuss any 3 functions of operating systems. (9 marks) 2. Discuss any 3 factors affecting the choice of an operating systems. (9 marks) 3. Discuss the following types of operating systems. - Multi tasking - Multi processing - Multi user - Real time (12 marks) 1. 3 functions of operating systems are as follow: a) Manage the computer resources such as central processing unit, memory, disk drives and printer. In other words it acts like a translator which allows the application software to communicate with the computer hardware. b) Caretaker which making sure that date is saved in the right place, programs are loaded into memory properly and that the computer's filing system is all kept in order. c) Execute and provide services for applications software in other words as system tools (programs) used to monitor computer performance, debug problems, or maintain parts of the system. A set of libraries or functions which programs may use to perform specific tasks especially relating to interfacing with computer system components. 2. 3 factors affecting the choice of an operating system are as follow: a) Choice of processor and hardware for example if server machine is a Sun computer then will be forced to use Solaris which is Sun's version of UNIX. b) A hardware or software protocol, contained in the electronics of the disk controller and disk drive, that manages the exchange of data between the drive and computer. The most common interfaces for small computer systems are AT (IDE) and SCSI. c) Compatibility of computer networks types including LANs and WANs, for example UNIX and Window NT are usually use to become the mainframe of WANs networking system. 3. a)Multi tasking - In a multitasking operating system where multiple programs can be running at the same time, the operating system determines which applications should run in what order and how much time should be allowed for each application before giving another application a turn. Examples of multi tasking operating system are UNIX and Window 2000. b)Multi processing - An operating system capable of supporting and utilizing more than one computer processor for example Linux, UNIX, Windows 2000. c)Multi user - A multi user operating system allows for multiple users

Tetewterwtfete

Ms. Czapski’s 1st, 2nd, 5th, and 6th Hour Advanced Placement English Language and Composition Classes Name: __________________________________________ Hour: ________ Date: _____________________ Introduction to Writing the Precis DIRECTIONS: Please thoughtfully answer each of the following questions about Geoffrey Nunberg’s The –Ism Schism; How Much Wallop Can a Simple Word Pack, Ellen Goodman’s In Praise of a Snail’s Pace, and Ronald J. Glasser’s We are not Immune: Influenza, SARS, and the Collapse of Public Health. You may write directly on this worksheet. For Geoffrey Nunberg’s The Ism Schism; How Much Wallop Can a Simple Word Pack: 1. ) What is the complete name of the author of this article? _____________________ 2. ) Who is this author? What are his/her expertise in relation to this topic? What is his/her experience with this topic? How did he/she gain his/her knowledge to compose this article? Use a short phrase to answer this question: ____________________________________________________________ ______________________ 3. ) What is the genre of this work (what type of writing is it)? ________________________________________ 4. ) What is the complete title of the work? _______________________________________________________ 5. ) What is the publication date of this piece of writing? _____________________________________________ 6. ) Is any other interesting or noteworthy publication information included? If so, what? ___________________ 7. ) Please use a rhetorically accurate verb (such as â€Å"assert,† â€Å"argue, † â€Å"suggest,† â€Å"imply,† â€Å"claim,† etc. ); and a THAT clause containing the major assertion (thesis statement) about the work. Avoid the use of more general words such as â€Å"writes† and â€Å"states. † The THAT clause is designed to demand a complete statement: a grammatical subject (the topic of the essay) and predicate (the claim that is made about that topic). If the THAT clause is not employed, you will end up allowing â€Å"about† and â€Å"how† to slip out in stating the thesis: i. e. , â€Å"Sheridan Baker writes about attitudes in writing† or â€Å"†¦ states how attitudes affect writing†   Ã¢â‚¬â€ neither of which reports what he claims to be true about attitudes. _________________________________________________ ____________________________________________________________ __________________________ 8. ) Explain how the author develops and/or supports the thesis, preferably in chronological order – identifying the writing techniques he/she utilized to achieve this. Sometimes it works best to report the order of development: â€Å"The author develops this assertion first, by applying these techniques to two poems; second, by providing definitions; and third, by explaining the history of each approach. A more general statement may also work in the second sentence: â€Å"The author develops this idea by comparing and contrasting the lives of these two Civil War heroes. † In works of literature you may provide a short plot summary: â€Å"Hemingway develops this idea through a sparse narrative about the ‘initiation' of a young boy who observes in one night both a birth and a death. † ________________________________________________________ ____________________________________________________________ __________________________ 9. What is the author's apparent purpose of this piece (introduce with the infinitive â€Å"to†)? Try not to simply restate the thesis: â€Å"The author's purpose is to prove that†¦ † Remember that one’s purpose is always to put forward a thesis, but there are others as well. The infinitive â€Å"to† phrase should transcend a phrase such as â€Å"Her purpose is to inform;† look beyond such a simplistic response to assess what the author wants the audience to do or to feel as a result of reading the work. ____________________________________________ ____________________________________________________________ _________________________ 10. ) Provide a description of the intended audience and/or the relationship the author establishes with the audience. Ask yourself how the language of the work excludes certain audiences (non-specialists would not understand the terminology; children would not understand the irony) in order to see that the author did make certain assumptions about the pre-existing knowledge of the audience. You may also report the author's tone. ____________________________________________________________ ________________ ___________________________________________________________ _________________________ For Ellen Goodman’s In Praise of a Snail’s Pace: 1. ) What is the complete name of the author of this article? __________________________________________ 2. ) Who is this author? What are his/her expertise in relation to this topic? What is his/her experience with this topic? How did he/she gain his/her knowledge to compose this article? Use a short phrase to answer this question: ____________________________________________________________ ______________________ 3. What is the genre of this work (what type of writing is it)? _________________________________________ 4. ) What is the complete title of the work? _______________________________________________________ 5. ) What is the publication date of this piece of writing? _____________________________________________ 6. ) Is any other interesting or noteworthy publication information included? If so, what? ___________________ 7. ) Please use a rhetorically accurate verb (such as â€Å"assert,† â€Å"argue,à ¢â‚¬  â€Å"suggest,† â€Å"imply,† â€Å"claim,† etc. ); and a THAT clause containing the major assertion (thesis statement) about the work. Avoid the use of more general words such as â€Å"writes† and â€Å"states. † The THAT clause is designed to demand a complete statement: a grammatical subject (the topic of the essay) and predicate (the claim that is made about that topic). If the THAT clause is not employed, you will end up allowing â€Å"about† and â€Å"how† to slip out in stating the thesis: i. e. , â€Å"Sheridan Baker writes about attitudes in writing† or â€Å"†¦ states how attitudes affect writing†   Ã¢â‚¬â€ neither of which reports what he claims to be true about attitudes. _________________________________________________ ____________________________________________________________ __________________________ 8. ) Explain how the author develops and/or supports the thesis, preferably in chronological order – identifying the writing techniques he/she utilized to achieve this. Sometimes it works best to report the order of development: â€Å"The author develops this assertion first, by applying these techniques to two poems; second, by providing definitions; and third, by explaining the history of each approach. A more general statement may also work in the second sentence: â€Å"The author develops this idea by comparing and contrasting the lives of these two Civil War heroes. † In works of literature you may provide a short plot summary: â€Å"Hemingway develops this idea through a sparse narrative about the ‘initiation' of a young boy who observes in one night both a birth and a death. † ________________________________________________________ ____________________________________________________________ __________________________ 9. What is the author's apparent purpose of this piece (introduce with the infinitive â€Å"to†)? Try not to simply restate the thesis: â€Å"The author's purpose is to prove that†¦ † Remember that one’s purpose is always to put forward a thesis, but there are others as well. The infinitive â€Å"to† phrase should transcend a phrase such as â€Å"Her purpose is to inform;† look beyond such a simplistic response to assess what the author wants the audience to do or to feel as a result of reading the work. ____________________________________________ ____________________________________________________________ _________________________ 10. ) Provide a description of the intended audience and/or the relationship the author establishes with the audience. Ask yourself how the language of the work excludes certain audiences (non-specialists would not understand the terminology; children would not understand the irony) in order to see that the author did make certain assumptions about the pre-existing knowledge of the audience. You may also report the author's tone. ____________________________________________________________ ________________ For Ronald J. Glasser’s We are not Immune: Influenza, SARS, and the Collapse of Public Health: 1. ) What is the complete name of the author of this article? __________________________________________ 2. ) Who is this author? What are his/her expertise in relation to this topic? What is his/her experience with this topic? How did he/she gain his/her knowledge to compose this article? Use a short phrase to answer this question: ____________________________________________________________ ______________________ 3. ) What is the genre of this work (what type of writing is it)? ________________________________________ 4. ) What is the complete title of the work? _______________________________________________________ 5. ) What is the publication date of this piece of writing? _____________________________________________ 6. ) Is any other interesting or noteworthy publication information included? If so, what? ___________________ 7. ) Please use a rhetorically accurate verb (such as â€Å"asser t,† â€Å"argue,† â€Å"suggest,† â€Å"imply,† â€Å"claim,† etc. ); and a THAT clause containing the major assertion (thesis statement) about the work. Avoid the use of more general words such as â€Å"writes† and â€Å"states. † The THAT clause is designed to demand a complete statement: a grammatical subject (the topic of the essay) and predicate (the claim that is made about that topic). If the THAT clause is not employed, you will end up allowing â€Å"about† and â€Å"how† to slip out in stating the thesis: i. e. , â€Å"Sheridan Baker writes about attitudes in writing† or â€Å"†¦ states how attitudes affect writing†   Ã¢â‚¬â€ neither of which reports what he claims to be true about attitudes. _________________________________________________ ____________________________________________________________ __________________________ 8. ) Explain how the author develops and/or supports the thesis, preferably in chronological order – identifying the writing techniques he/she utilized to achieve this. Sometimes it works best to report the order of development: â€Å"The author develops this assertion first, by applying these techniques to two poems; second, by providing definitions; and third, by explaining the history of each approach. A more general statement may also work in the second sentence: â€Å"The author develops this idea by comparing and contrasting the lives of these two Civil War heroes. † In works of literature you may provide a short plot summary: â€Å"Hemingway develops this idea through a sparse narrative about the ‘initiation' of a young boy who observes in one night both a birth and a death. † ________________________________________________________ ____________________________________________________________ __________________________ 9. ) What is the author's apparent purpose of this piece (introduce with the infinitive â€Å"to†)? Try not to simply restate the thesis: â€Å"The author's purpose is to prove that†¦ † Remember that one’s purpose is always to put forward a thesis, but there are others as well. The infinitive â€Å"to† phrase should transcend a phrase such as â€Å"Her purpose is to inform;† look beyond such a simplistic response to assess what the author wants the audience to do or to feel as a result of reading the work. ____________________________________________ ____________________________________________________________ __________________________