4,432 research outputs found
Generalized -conformal change and special Finsler spaces
In this paper, we investigate the change of Finslr metrics which we refer to as a
generalized -conformal change. Under this change, we study some special
Finsler spaces, namely, quasi C-reducible, semi C-reducible, C-reducible,
-like, -like and -like Finsler spaces. We also obtain the
transformation of the T-tensor under this change and study some interesting
special cases. We then impose a certain condition on the generalized
-conformal change, which we call the b-condition, and investigate the
geometric consequences of such condition. Finally, we give the conditions under
which a generalized -conformal change is projective and generalize some
known results in the literature.Comment: References added, some modifications are performed, LateX file, 24
page
Assessment of rock slope stability and structurally controlled failures along Samma escarpment road, Asir Region (Saudi Arabia)
Samma escarpment road is located in Asir Region, Saudi Arabia. It is located NW of Abha city. This escarpment road represents a major corridor in the area which connects different cities and touristic resorts in the region. It is descended from Sudah plateau at about 2700 m above sea level (asl) toward Wadi al Aws at about 1500 m asl. The total length of the road section is about 8 km which is passing through a highly mountainous area characterized by a complex geological and structural elements. This road has been exposed to frequent slope failures from time to time due to various factors such as intense rain storms, different geological and structural elements (weak rocks, shear zones, and faults), road characteristics (different horizontal/vertical curvatures and narrow road section), and human activities (uncontrolled rock cuts). Many sliding events have been documented along this escarpment road, particularly during and following rainstorms. The purpose of this paper is to evaluate the geology and structures by applying the rock mass rating (RMR) and slope stability (structurally controlled failures) along the Samma escarpment road. The stability analysis was performed using two Dips and RockPack III programs with the help of RocLab software. The Summa escarpment rock cuts were classified into 51 stations which were investigated in detail. Results indicated that most rock stations are poor quality, and 31, 32, and 41 stations are stable, 4, 6, and 7 stations are marginally stable, and 16, 13, and 3 stations are potentially unstable due to planar, wedge, and toppling failures, respectively. Finally, different recommendations and remediation methods were suggested as mitigation measures
A Survey on Retrieval of Mathematical Knowledge
We present a short survey of the literature on indexing and retrieval of
mathematical knowledge, with pointers to 72 papers and tentative taxonomies of
both retrieval problems and recurring techniques.Comment: CICM 2015, 20 page
Calli Essential Oils Synergize with Lawsone against Multidrug Resistant Pathogens.
The fast development of multi-drug resistant (MDR) organisms increasingly threatens global health and well-being. Plant natural products have been known for centuries as alternative medicines that can possess pharmacological characteristics, including antimicrobial activities. The antimicrobial activities of essential oil (Calli oil) extracted from the Calligonum comosum plant by hydro-steam distillation was tested either alone or when combined with lawsone, a henna plant naphthoquinone, against MDR microbes. Lawsone showed significant antimicrobial activities against MDR pathogens in the range of 200-300 µg/mL. Furthermore, Calli oil showed significant antimicrobial activities against MDR bacteria in the range of 180-200 µg/mL, Candida at 220-240 µg/mL and spore-forming Rhizopus fungus at 250 µg/mL. Calli oil's inhibition effect on Rhizopus, the major cause of the lethal infection mucormycosis, stands for 72 h, followed by an extended irreversible white sporulation effect. The combination of Calli oil with lawsone enhanced the antimicrobial activities of each individual alone by at least three-fold, while incorporation of both natural products in a liposome reduced their toxicity by four- to eight-fold, while maintaining the augmented efficacy of the combination treatment. We map the antimicrobial activity of Calli oil to its major component, a benzaldehyde derivative. The findings from this study demonstrate that formulations containing essential oils have the potential in the future to overcome antimicrobial resistance
On Finslerized Absolute Parallelism spaces
The aim of the present paper is to construct and investigate a Finsler
structure within the framework of a Generalized Absolute Parallelism space
(GAP-space). The Finsler structure is obtained from the vector fields forming
the parallelization of the GAP-space. The resulting space, which we refer to as
a Finslerized Parallelizable space, combines within its geometric structure the
simplicity of GAP-geometry and the richness of Finsler geometry, hence is
potentially more suitable for applications and especially for describing
physical phenomena. A study of the geometry of the two structures and their
interrelation is carried out. Five connections are introduced and their torsion
and curvature tensors derived. Some special Finslerized Parallelizable spaces
are singled out. One of the main reasons to introduce this new space is that
both Absolute Parallelism and Finsler geometries have proved effective in the
formulation of physical theories, so it is worthy to try to build a more
general geometric structure that would share the benefits of both geometries.Comment: Some references added and others removed, PACS2010, Typos corrected,
Amendemrnts and revisions performe
Post-Test Analysis of SIRIO Facility Data by System Thermal-Hydraulic Codes for LFR Application
As part of the R&D activities supporting Generation IV innovative nuclear technologies, an experimental facility named SIRIO has been designed and constructed to test and validate a new concept of Decay Heat Removal system at a relevant scale for Gen-IV Lead-cooled Fast Reactor (LFR), in particular for the DEMO LFR ALFRED. This innovative system provides a safe long-term cooling condition of the reactor coolant system with no need of external action or energy supply, and claims capability to passively control the heat removed by the ultimate heat sink thanks to non-condensable gases.
This new concept is attractive for LFRs because it can prevent the early freezing of lead, which is a concern after the proper intervention of the DHRs. In addition, for water cooled reactors, passive control of heat transfer capability reduces the thermal stresses on the materials, smoothing the fluid internal thermal gradients and the depressurization rate.
In this work, SIRIO facility is described, along with the numerical model developed using the RELAP5/Mod3.3 thermal-hydraulic system code. Part of the efforts in the experimental campaign within the EU project PIACE aims at reproducing the conditions of ALFRED in Stage 2 configuration (i.e., loop and gas pressure set at 180 and 110 bar, respectively). The experimental outcomes are compared
with those obtained with RELAP5 code to validate the numerical tool for LFRs applications and to assess the code capability in reproducing two-phase natural circulation conditions with noncondensable gases and the system response during accidental scenarios
Magnetic resonance spectroscopy of perpendicularly magnetized permalloy multilayer disks
Using a Magnetic Resonance Force Microscope, we compare the ferromagnetic
resonance spectra of individual micron-size disks with identical diameter, 1
m, but different layer structures. For a disk composed of a single 43.3 nm
thick permalloy (Py) layer, the lowest energy mode in the perpendicular
configuration is the uniform precession. The higher energy modes are standing
spin-waves confined along the diameter of the disk. For a Cu(30)/Py(100)/Cu(30)
nm multilayer structure, it has been interpreted that the lowest energy mode
becomes a precession localized at the Cu/Py interfaces. When the multilayer is
changed to Py(100)/Cu(10)/Py(10) nm, this localized mode of the thick layer is
coupled to the precession of the thin layer
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