1,063 research outputs found
A Sawtooth Permanent Magnetic Lattice for Ultracold Atoms and BECs
We propose a new permanent magnetic lattice for creating periodic arrays of
Ioffe-Pritchard permanent magnetic microtraps for holding and controlling
ultracold atoms and Bose-Einstein condensates (BECs). Lattice can be designed
on thin layer of magnetic films such as . In
details, we investigate single layer and two crossed layers of sawtooth
magnetic patterns with thicknesses of 50 and 500nm respectively with a
periodicity of 1m. Trap depth and frequencies can be changed via an
applied bias field to handle tunneling rates between lattice sites. We present
analytical expressions and using numerical calculations show that this lattice
has non-zero potential minima to avoid majorana spin flips. One advantage of
this lattice over previous ones is that it is easier to manufacture.Comment: 8 pages, 6 figure
Mass Movement Landslide (Jun 10, 2005) Along Sarab- Ardebil Main Road (West Slope Savalan Volcanic Mountain)- Azerbaijan- Iran
In Azerbaijan, development of landslide hazard areas is occurring at a greater rate than in previous years. Mass movements (landslides, Mass wasting) may take place suddenly and catastrophically, resulting in debris and snow avalanches, lahars, rock falls, flows (debris, quick clay, loess and dry or wet sand and silt) .The region under survey is located in a valley named “ILANJIG”. Its slope is about 30 to 40 percent and the main road of Tabriz- Sarab- Ardebil is routed across this valley. This valley is a Fault Valley and residual signs of old landslides can be observed along the valley. Construction of Tabriz- Ardebil main road was started in 1991 and completed in 1997. Because of poor design of the road, and due to continuous penetration of rain and water from melted snow into the mass clay layers and its volume swelling, shear strength of clay decreased and heavy loads from upper volcanic rock blocks lead to sudden fracture and resulted in a huge landslide. Approximate volume of main landslide was [1.6x106]/0.2[m3/km2]. Landslides are the most predictable geological hazards, among other natural hazards
Effect of municipal wastewater with manure and fertilizer on yield and quality characteristics of forage in corn
In order to study the effects of wastewater with two kinds of fertilizers (manure and chemical fertilizer) on yield and quality characteristics of forage in corn, a field experiment was conducted in the Universityof Zabol in Iran during 2007 growing season. The experiment was conducted in split plot design with three replications. The treatment were comprised of two levels of irrigation water (W1 = Well water andW2 = Wastewater) in the main plot and five levels of fertilizer (F1 = Control; F2 = Manure, 30 ton/ha; F3 = Manure, 15 ton/ha; F4 = NPK: 350, 200 and 100 kg/ha; and F5 = NPK: 175, 100 and 50 kg/ha) in the subplot. Results showed that irrigation with wastewater significantly increases the fresh and dry forage yield of corn than well water. Treatment of treated wastewater also had a significant influence on crude protein content, ash percentage and macro elements (N, P and K) contents in corn forage (P < 5%). But wastewater had no significant effect on Fe, Mn and Zn elements content. The highest fresh and dry forage yield and the most crude protein content, ash percentage and macro elements (N, P and K) contents were obtained from F4 (NPK: 350, 200 and 100 kg/ha) treatment. However, the highest Fe, Mn and Zn elements content were obtained from F2 (Manure: 30 ton/ha) treatment
Cooling Flows of Self-Gravitating, Rotating, Viscous Systems
We obtain self-similar solutions that describe the dynamics of a
self-gravitating, rotating, viscous system. We use simplifying assumptions; but
explicitly include viscosity and the cooling due to the dissipation of energy.
By assuming that the turbulent dissipation of energy is as power law of the
density and the speed v_{rms} and for a power-law dependence of viscosity on
the density, pressure, and rotational velocity, we investigate turbulent
cooling flows. It has been shown that for the cylindrically and the spherically
cooling flows the similarity indices are the same, and they depend only on the
exponents of the dissipation rate and the viscosity model. Depending on the
values of the exponents, which the mechanisms of the dissipation and viscosity
determine them, we may have solutions with different general physical
properties. The conservation of the total mass and the angular momentum of the
system strongly depends on the mechanisms of energy dissipation and the
viscosity model.Comment: 19 pages, 5 figures, To appear in ApJ (scheduled for the v574, July
20, 2002
Internet Addiction and its Predictors in Guilan Medical Sciences Students, 2012
Background: Internet is one of the technologies of the modern era that is being extensively used around the world. It is believed that excessive Internet use can be pathological and addictive. Though, academic use of the Internet is primarily intended for learning and research, students are one of the groups at risk of Internet addiction.
Objectives: Due to the expanding use of Internet among the university students, this study was conducted to examine the Internet addiction and its predictors among Guilan University of Medical Sciences students.
Materials and Methods: A cross-sectional study was conducted on 583 students during the first semester of 2012. A two-stage stratified random sampling was conducted and a two-part instrument was used for data collection. The first part of the instrument was consisted of questions about demographic characteristics and the second part was the Young's Internet addiction inventory. Chi-square, Kruskal-Wallis testes, Spearman correlation coefficient and ranked logistic regression were used for data analysis.
Results: About 5.7% of the students were moderately dependent to the Internet, while 44.1% were at risk for Internet addiction. Significant relationships were observed between the Internet addiction with age (P < 0.001), gender (P < 0.001), marital status (P < 0.001), major (P = 0.016), Grade point average (P = 0.017), semester of studying (P = 0.009) and student residence place (P = 0.014). However, no significant relationship was observed between the internet addiction score and level of discipline, parental job status and education level or the students’ accommodation.
Conclusion: About half of the participants in this study were at risk of Internet addiction. This finding can be a warning sign for the authorities in universities to pay more attention to this issue. A wide range of education along with empowering programs may be needed to inform the university students about the advantages and disadvantages of internet and the correct manner of using it
Multibody expansion of the local integrals of motion: How many pairs of particle-hole do we really need to describe the quasiparticles in the many-body localized phase?
The emergent integrability in a many-body localized (MBL) system can be well
characterized by the existence of the complete set of local integrals of motion
(LIOMs). Such exactly conserved and exponentially localized operators are often
understood as quasiparticle operators which can be expanded in terms of
single-particle operators dressed with different numbers of particle-hole
pairs. Here, we consider a one-dimensional XXZ spin- Heisenberg chain
in the presence of a random field and try to quantify the corrections needed to
be considered in the picture of quasiparticles associated with LIOMs due to the
presence of particle-hole excitations. To this end, we explicitly present the
multibody expansion of LIOM creation operators of the system in the MBL regime.
We analytically obtain the coefficients of this expansion and discuss the
effect of higher-order corrections associated with different numbers of
particle-hole excitations. Our analysis shows that depending on the
localization length of the system, there exist a regime in which the
contributions that come from higher-order terms can break down the effective
one-particle description of the LIOMs and such quasiparticles become
essentially many-body-like
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