Ground state factorization of heterogeneous spin models in magnetic fields

The exact factorized ground state of a heterogeneous (ferrimagnetic) spin model which is composed of two spins ($\rho, \sigma$) has been presented in detail. The Hamiltonian is not necessarily translational invariant and the exchange couplings can be competing antiferromagnetic and ferromagnetic arbitrarily between different sub-lattices to build many practical models such as dimerized and tetramerized materials and ladder compounds. The condition to get a factorized ground state is investigated for non-frustrated spin models in the presence of a uniform and a staggered magnetic field. According to the lattice model structure we have categorized the spin models in two different classes and obtained their factorization conditions. The first class contains models in which their lattice structures do not provide a single uniform magnetic field to suppress the quantum correlations. Some of these models may have a factorized ground state in the presence of a uniform and a staggered magnetic field. However, in the second class there are several spin models in which their ground state could be factorized whether a staggered field is applied to the system or not. For the latter case, in the absence of a staggered field the factorizing uniform field is unique. However, the degrees of freedom for obtaining the factorization conditions are increased by adding a staggered magnetic field.Comment: 16 pages, 6 figures, 1 table, Accepted in Progress of Theoretical Physic

Factorized ground state for a general class of ferrimagnets

We have found the exact (factorized) ground state of a general class of ferrimagnets in the presence of a magnetic field which covers the frustrated, anisotropic and long range interactions for arbitrary dimensional space. In particular cases, our model represents the bond-alternating, ferromagnet-antiferromagnet and also homogeneous spin $s$ model. The factorized ground state is a product of single particle kets on a bipartite lattice composed of two different spins ($\rho, \sigma$). The spin waves analysis around the exact ground state show two branch of excitations which is the origin of two dynamics of the model. The signature of these dynamics is addressed as a peak and a broaden bump in the specific heat.Comment: 4 pages and 2 figures, some typos correcte

Explorations Into Continuity: An Heuristic, Artistic Inquiry into the Interplay Between Work as a Dance/Movement Therapist and Service within the Bahá’í Community

The purpose of this thesis was to explore the concept of integration between two main aspects of my life: my professional career as a dance/movement therapist on an inpatient adolescent behavioral health unit, and service guided by Bahá’í teachings in a neighborhood-based setting. Literature reviewed encompassed instances of Rudolf von Laban’s Effort elements found in the Bahá’í Writings, as well as research on the integration between the mind, body and spirit, the history of religion and mental health, and the current relationship between religion and mental health. Both artistic inquiry and heuristic methodologies were used to guide my research. Through Moustakas’s method of data analysis – immersion, incubation, illumination, explication, and creative synthesis – certain themes surfaced that shed light on my personal embodied experience of integration, and its implications both in a dance/movement therapy (DMT) and religious vein. Two major themes included the role of improvisation in integration and the shift from fragmented language and movement to bodily integration found through utilization of the Laban Movement Analysis (LMA) Body category, in place of Effort. This study informs not only my own orientation towards integration, but also provides a platform from which both dance/movement therapists and any faith-based mental health practitioners can conceptualize integration and make it a more conscious part of their work

The Studies of Garnet Deposits of Iran from Industrial Application Point of View

Garnet is a natural abrasive industrial mineral which produced by four producer In three countries. Garnets include igneous Rocks have formed under metamorphosed and limestone foliated . The most important of the garnet deposits of Iran is located in Koh-E-Gabri, Hamadan and Sangbast in Mashhad .In Iran Garnet is sold about 187$/t, but the range of price in other countries is approximately 160-280$/t. The information about Import and Export and determining the real price of Garnet in Iran is not avail-able definitely. According to the economical and engineer-ing evaluation accomplished on Garnets mine of Iran ,it shows that this mine with greatest Rate of Return ( IRR = 34 %) is one of the best and the most hopeful Garnets mine in Iran. the mines such as Azandrain and Sangbast in Mashahad haven't shown hopeful result Due to its nature

The Characterization and Classification Studies of Bent-onite Mines in IRAN for Application in Drilling and Foundry by AHP Technique

Bentonite is a clay groups which is a very important in todays industry, according to its chemical and physical properties. The most of the consumption of Bentonite in IRAN are in the fields of drilling and foundry. According to the drilling and foundry standards of IRAN, about 25 Bentonite mines have been identified and classified and lastly decided by AHP (Analytical Hierarchy Process) technique. More than 300 tests about the parameters like wetness, swelling, compressive strength, dry strength, pH, methylen blue, gelling index, yield, viscosity, plastic viscosity, filter loss and sieve analysis have been investigated. The Tashtabkhor mine with highest score (19.85) and the Chahkeshmir mine with lowest score (4.523) in drilling and the Boteh gaz mine with highest score (19.37) and the Gol khandan mine with lowest score (5.094)in foundry, were the mines selected amount 25 mines

Phase diagram of the XXZ ferrimagnetic spin-(1/2, 1) chain in the presence of transverse magnetic field

We investigate the phase diagram of an anisotropic ferrimagnet spin-(1/2, 1) in the presence of a non-commuting (transverse) magnetic field. We find a magnetization plateau for the isotropic case while there is no plateau for the anisotropic ferrimagnet. The magnetization plateau can appear only when the Hamiltonian has the U(1) symmetry in the presence of the magnetic field. The anisotropic model is driven by the magnetic field from the N\'{e}el phase for low fields to the spin-flop phase for intermediate fields and then to the paramagnetic phase for high fields. We find the quantum critical points and their dependence on the anisotropy of the aforementioned field-induced quantum phase transitions. The spin-flop phase corresponds to the spontaneous breaking of Z2 symmetry. We use the numerical density matrix renormalization group and analytic spin wave theory to find the phase diagram of the model. The energy gap, sublattice magnetization, and total magnetization parallel and perpendicular to the magnetic field are also calculated. The elementary excitation spectrums of the model are obtained via the spin wave theory in the three different regimes depending on the strength of the magnetic field.Comment: 14 pages, 11 eps figure

Optical quenching and recovery of photoconductivity in single-crystal diamond

We study the photocurrent induced by pulsed-light illumination (pulse duration is several nanoseconds) of single-crystal diamond containing nitrogen impurities. Application of additional continuous-wave light of the same wavelength quenches pulsed photocurrent. Characterization of the optically quenched photocurrent and its recovery is important for the development of diamond based electronics and sensing

Influence of anodizing process on fatigue life of a machined aluminium alloy

In order to investigate the coupled effects of machining and anodizing processes on fatigue life of alloy 7010-T7451, a series of rotating bending fatigue tests were conducted at 60Hz. In the as machined condition, test results showed that fatigue life is surface roughness dependent and that fatigue life decreases with an increase in surface roughness and this effect is found to be more pronounced in high cycle fatigue where major portion of fatigue life is consumed in nucleating the cracks. Effects of pretreatments, like degreasing and pickling employed prior to anodizing, on fatigue life of the given alloy were also studied. Results demonstrated that degreasing showed no change in fatigue life while pickling had negative impact on fatigue life of specimens. The small decrease in fatigue life of anodized specimens as compare to pickled specimens is attributed to brittle and microcracking of the coating. Scanning electron microscopic (SEM) examination revealed multi-site crack initiation for the pickled and anodized specimens. SEM examination showed that pickling solution attacked the grain boundaries and intermetallic inclusions present on the surface resulting in pits formation. These pits are of primary concern with respect to accelerated fatigue crack nucleation and subsequent anodized coating formation

Preliminary report of hepatitis B virus genotype prevalence in Iran

Aim: To determine the prevalence of hepatitis B virus (HBV) genotypes in Iranian hepatitis B surface antigen (HBsAg) carriers, chronic hepatitis B and cirrhotic patients. Methods: A total of 109 HBsAg-positive patients were included in this study. HBV genotypes were determined by using INNO-LiPA methodology which is based on the reverse hybridization principle. Results: The distribution of patients with different stages of liver disease was as follows: 95 (86.4) chronic hepatitis, 11 (10) liver cirrhosis, and 3 (2.7) inactive carrier. Of the chronic hepatitis and liver cirrhosis patients, 26.4 were HBeAg-positive while 70 were HBeAg-negative. Genotype D was the only detected type found in all patients. Conclusion: Classifying HBV into genotypes has to be cost-effective and clinically relevant. Our study indicates that HBV genotype D prevails in the Mediterranean area, Near and Middle East, and South Asia. Continued efforts for understanding HBV genotype through international co-operation will reveal further virological diffierences of the genotypes and their clinical relevance. © 2006 The WJG Press. All rights reserved

Key traveller groups of relevance to spatial malaria transmission: a survey of movement patterns in four sub-Saharan African countries

Background: As malaria prevalence declines in many parts of the world due to widescale control efforts and as drug-resistant parasites begin to emerge, a quantitative understanding of human movement is becoming increasingly relevant to malaria control. However, despite its importance, significant knowledge gaps remain regarding human movement, particularly in sub-Saharan Africa. Methods: A quantitative survey of human movement patterns was conducted in four countries in sub-Saharan Africa: Mali, Burkina Faso, Zambia, and Tanzania, with three to five survey locations chosen in each country. Questions were included on demographic and trip details, malaria risk behaviour, children accompanying travellers, and mobile phone usage to enable phone signal data to be better correlated with movement. A total of 4352 individuals were interviewed and 6411 trips recorded. Results: A cluster analysis of trips highlighted two distinct traveller groups of relevance to malaria transmission: women travelling with children (in all four countries) and youth workers (in Mali). Women travelling with children were more likely to travel to areas of relatively high malaria prevalence in Mali (OR = 4.46, 95 % CI = 3.42–5.83), Burkina Faso (OR = 1.58, 95 % CI = 1.23–1.58), Zambia (OR = 1.50, 95 % CI = 1.20–1.89), and Tanzania (OR = 2.28, 95 % CI = 1.71–3.05) compared to other travellers. They were also more likely to own bed nets in Burkina Faso (OR = 1.77, 95 % CI = 1.25–2.53) and Zambia (OR = 1.74, 95 % CI = 1.34 2.27), and less likely to own a mobile phone in Mali (OR = 0.50, 95 % CI = 0.39–0.65), Burkina Faso (OR = 0.39, 95 % CI = 0.30–0.52), and Zambia (OR = 0.60, 95 % CI = 0.47–0.76). Malian youth workers were more likely to travel to areas of relatively high malaria prevalence (OR = 23, 95 % CI = 17–31) and for longer durations (mean of 70 days cf 21 days, p < 0.001) compared to other travellers. Conclusions: Women travelling with children were a remarkably consistent traveller group across all four countries surveyed. They are expected to contribute greatly towards spatial malaria transmission because the children they travel with tend to have high parasite prevalence. Youth workers were a significant traveller group in Mali and are expected to contribute greatly to spatial malaria transmission because their movements correlate with seasonal rains and hence peak mosquito densities. Interventions aimed at interrupting spatial transmission of parasites should consider these traveller groups