Two Poems

Encina Mei Roh is a second year Political Science major at Simon Fraser University. She is the founder and co president of the Writer’s Art, which leads free poetry programs at nursing homes and recreation centers throughout the lower mainland. Apart from her work as a legal intern and tutor for SFU, she enjoys writing and painting

Study on interfacial heat transfer coefficient at metal/die interface during high pressure die casting process of AZ91D alloy

The high pressure die casting (HPDC) process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today’s manufacturing industry.In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were Measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC) was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger,and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified,when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior

Light anti-nuclei production in pp collisions at s\sqrt{s}=7 and 14 TeV

A dynamically constrained coalescence model based on the phase space quantization and classical limit method was proposed to investigate the production of light nuclei (anti-nuclei) in non-single diffractive (NSD) pp collisions at $\sqrt{s}$=7 and 14 TeV. This calculation was based on the final hadronic state in the PYTHIA and PACIAE model simulations, the event sample consisted of 1.2$\times 10^8$ events in both simulations. The PACIAE model calculated $\bar D$ yield of 6.247$\times 10^{-5}$ in NSD pp collisions at $\sqrt{s}$=7 TeV is well comparing with the ALICE rough datum of 5.456$\times 10^{-5}$. It indicated the reliability of proposed method in some extent. The yield, transverse momentum distribution, and rapidity distribution of the $\bar D$, $^3{\bar{He}}$, and $_{\bar\Lambda} ^3{\bar H}$ in NSD pp collisions at $\sqrt{s}$=7 and 14 TeV were predicted by PACIAE and PYTHIA model simulations. The yield resulted from PACIAE model simulations is larger than the one from PYTHIA model. This might reflect the role played by the parton and hadron rescatterings.Comment: 5 pages, 2 figure

Trace initial interaction from final state observable in relativistic heavy ion collisions

In order to trace the initial interaction in ultra-relativistic heavy ion collision in all azimuthal directions, two azimuthal multiplicity-correlation patterns -- neighboring and fixed-to-arbitrary angular-bin correlation patterns -- are suggested. From the simulation of Au + Au collisions at 200 GeV by using the Monte Carlo models RQMD with hadron re-scattering and AMPT with and without string melting, we observe that the correlation patterns change gradually from out-of-plane preferential one to in-plane preferential one when the centrality of collision shifts from central to peripheral, meanwhile the anisotropic collective flow v_2 keeps positive in all cases. This regularity is found to be model and collision energy independent. The physics behind the two opposite trends of correlation patterns, in particular, the presence of out-of-plane correlation patterns at RHIC energy, are discussed.Comment: 5pages, 4figure

The Optimal Inventory Policy with the Reusable Raw Material and Imperfect Items

This paper covers four topics regarding inventory models, namely reusable raw material, the EPQ model, imperfect-quality items, and the present value method. The relevant cost value used in traditional EPQ models does not include the stockholding cost of raw material, which makes such models unsuitable for investigating production. Because people in the world are attempting to reduce the impact of environmental impairment and increasing market competition, all products are manufactured from 100% reusable raw material and are screened during the manufacturing process. By taking the fixed proportion of imperfect-quality items and the time value into account and applying the present value method to analyze optimal inventory policies, this study creates a modified EPQ inventory model that is close to real life we meet. Furthermore, this model aims to promote the reputation of a company and ascertain its costs accurately

On Holographic Dual of the Dyonic Reissner-Nordstr\"om Black Hole

It is shown that the hidden conformal symmetry, namely $SO(2,2) \sim SL(2,R)_L \times SL(2,R)_R$ symmetry, of the non-extremal dyonic Reissner-Nordstr\"om black hole can be probed by a charged massless scalar field at low frequencies. The existence of such hidden conformal symmetry suggests that the field theory holographically dual to the 4D Reissner-Nordstr\"om black hole indeed should be a 2D CFT. Although the associated AdS$_3$ structure does not explicitly appear in the near horizon geometry, the primary parameters of the dual CFT$_2$ can be exactly obtained without the necessity of embedding the 4D Reissner-Nordstr\"om black hole into 5D spacetime. The duality is further supported by comparing the absorption cross sections and real-time correlators obtained from both the CFT and the gravity sides.Comment: 18 pages, no figure, typos correcte

Twofold Hidden Conformal Symmetries of the Kerr-Newman Black Hole

In this paper, we suggest that there are two different individual 2D CFTs holographically dual to the Kerr-Newman black hole, coming from the corresponding two possible limits --- the Kerr/CFT and Reissner-Nordstr\"om/CFT correspondences, namely there exist the Kerr-Newman/CFTs dualities. A probe scalar field at low frequencies turns out can exhibit two different 2D conformal symmetries (named by $J$- and $Q$-pictures, respectively) in its equation of motion when the associated parameters are suitably specified. These twofold dualities are supported by the matchings of entropies, absorption cross sections and real time correlators computed from both the gravity and the CFT sides. Our results lead to a fascinating "microscopic no hair conjecture" --- for each macroscopic hair parameter, in additional to the mass of a black hole in the Einstein-Maxwell theory, there should exist an associated holographic CFT$_2$ description.Comment: 21 pages, 1 figure, typos correcte

Morpholinium 4-amino-5-meth­oxy-2-methyl­benzensulfonate

In the crystal structure of the title compound, C4H10NO+·C8H10NO4S−, the components are linked by N—H⋯O hydrogen bonds, forming a centrosymmetric 2:2 aggregate. The aggregates are further connected by N—H⋯O hydrogen bonds between the anions, forming a double-tape structure along the a axis

6-Isopropyl-5-meth­oxy-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one

In the title compound, C14H15N5O2, the whole mol­ecule apart from the terminal C atoms of the isopropyl group is located on a crystallographic mirror plane. An intra­molecular C—H⋯N hydrogen-bonding inter­action may stabilize the mol­ecular conformation. The crystal packing features weak slipped π–π inter­actions between the pyrimidine and the phenyl rings of symmetry-related mol­ecules [centroid–centroid distance = 3.746 (1)Å, slippage of 1.574 Å]