177 research outputs found
Application of seismic attributes in structural study and fracture analysis of DQ oil field, Iran
The determination of the most unstable areas in oil fields is critical for addressing engineering problems of wellbore and sand production as well as geologic problems such as understanding dynamic constraints on hydrocarbon migration and fracture permeability. In this research work, coherency seismic attribute has been used for the determination of the most critical areas in terms of drilling stabilities in the DQ oil field, Iran. The results obtained have shown that the (1) predominant features are the SSEâNNW and NâS trends (2) the central part of the DQ structure shows the highest concentration of segment bundles, (3) the segment bundles seem to be aligned along some lineaments oriented SEâNW and SSEâNNW, and (4) on the eastern and western margins of the map there is an anomalous concentration of segments oriented EâW. It can be concluded that coherency attribute is a valuable tool for structural analysis highlighting those areas containing unstable features
A Suspended Array of Square Patch Metamaterial Absorbers for Terahertz Applications
A suspended array of square metallic patches on a thin dielectric layer is introduced as a terahertz absorber. The absorber is fabricated on a metalized substrate and the device exhibits metamaterial behavior at specific frequencies determined by the size of the patches. It is feasible to place patches with different sizes in an array formation for a broadband absorber. Design of the absorber is described using electromagnetic simulations. The absorber structure was fabricated on a silicon wafer and its characteristics were measured using a terahertz time domain spectroscope. The measured data match well the simulations indicating strong absorption peaks in a band of 0.5-2 THz
Metastability in spin polarised Fermi gases and quasiparticle decays
We investigate the metastability associated with the first order transition from normal to superfluid phases in the phase diagram of two-component polarised Fermi gases.We begin by detailing the dominant decay processes of single quasiparticles.Having determined the momentum thresholds of each process and calculated their rates, we apply this understanding to a Fermi sea of polarons by linking its metastability to the stability of individual polarons, and predicting a region of metastability for the normal partially polarised phase. In the limit of a single impurity, this region extends from the interaction strength at which a polarised phase of molecules becomes the groundstate, to the one at which the single quasiparticle groundstate changes character from polaronic to molecular. Our argument in terms of a Fermi sea of polarons naturally suggests their use as an experimental probe. We propose experiments to observe the threshold of the predicted region of metastability, the interaction strength at which the quasiparticle groundstate changes character, and the decay rate of polarons
Back gating of a two-dimensional hole gas in a SiGe quantum well
A device comprising a low-resistivity, n-type, Si substrate as a back gate to a p-type (boron), remote-doped, SiGe quantum well has been fabricated and characterized. Reverse and forward voltage biasing of the gate with respect to the two-dimensional hole gas in the quantum well allows the density of holes to be varied from 8 Ă 1011 cmâ2 down to a measurement-limited value of 4 Ă 1011 cmâ2. This device is used to demonstrate the evolution with decreasing carrier density of a re-entrant insulator state between the integer quantum Hall effect states with filling factors 1 and 3
One-pot, three-component synthesis of novel ÎŽ-sultam scaffolds via N-sulfonylationâintramolecular Michael sequences.
The synthesis of novel ÎŽ-sultam scaffolds utilizing one-pot, three-component reactions of 1,3-dicarbonyl compounds, primary aliphatic amines and substituted styrenesulfonyl chlorides is reported. A variety of six-membered sultams are obtained in moderate to good yields presumably via N-sulfonylationâintramolecular Michael addition sequences
Periodic array of complementary artificial magnetic conductor metamaterialsâbased multiband antennas for broadband wireless transceivers
Knowledge, Attitude, and Perception of Students Regarding Renewable Energies in Agriculture in Guilan, Iran
Transitioning from fossil to renewable energy is a global challenge, especially for countries with large fossil-fuel reserves and exports, such as Iran. This study analyses agricultural students' knowledge of, attitudes toward, and perceptions of renewable energies in the agriculture sector in Guilan Province in Iran. The research was based on a structured questionnaire comprising three sections: (i) respondents' socio-demographics; (ii) practicality and relevance of academic material and curriculum; and (iii) respondents' knowledge of and attitudes and perceptions toward renewable energies in agriculture. The results showed that students' attitudes regarding renewable energies ranked highest, and their perception was lowest. The results also showed a positive and significant relationship between the respondents' knowledge, marital status, age, and level of education. Moreover, respondents' age and educational level significantly impacted their attitudes. Cluster analysis divided students' behavior into three different clusters. These clusters were most affected by attitude. In clustering students' behavior towards using renewable energies, 38.5%, 33.5%, and 28% of respondents were positioned in the first, third, and second clusters, respectively. This is a pioneering study analyzing agricultural students' behavior regarding renewable energies in agriculture in Guilan Province, Iran. The results of this study can assist agricultural organizations, politicians in the field of energy, and local authorities in promoting sustainable energy in Guilan Province.Open Access funding is provided by the Qatar National Library.Scopu
Preclinical Incorporation Dosimetry of [18F]FACHâA Novel 18F-Labeled MCT1/MCT4 Lactate Transporter Inhibitor for Imaging Cancer Metabolism with PET
Overexpression of monocarboxylate transporters (MCTs) has been shown for a variety of human cancers (e.g., colon, brain, breast, and kidney) and inhibition resulted in intracellular lactate accumulation, acidosis, and cell death. Thus, MCTs are promising targets to investigate tumor cancer metabolism with positron emission tomography (PET). Here, the organ doses (ODs) and the effective dose (ED) of the first 18F-labeled MCT1/MCT4 inhibitor were estimated in juvenile pigs. Whole-body dosimetry was performed in three piglets (age: ~6 weeks, weight: ~13â15 kg). The animals were anesthetized and subjected to sequential hybrid Positron Emission Tomography and Computed Tomography (PET/CT) up to 5 h after an intravenous (iv) injection of 156 ± 54 MBq [18F]FACH. All relevant organs were defined by volumes of interest. Exponential curves were fitted to the timeâactivity data. Time and mass scales were adapted to the human order of magnitude and the ODs calculated using the ICRP 89 adult male phantom with OLINDA 2.1. The ED was calculated using tissue weighting factors as published in Publication 103 of the International Commission of Radiation Protection (ICRP103). The highest organ dose was received by the urinary bladder (62.6 ± 28.9 ”Sv/MBq), followed by the gall bladder (50.4 ± 37.5 ”Sv/MBq) and the pancreas (30.5 ± 27.3 ”Sv/MBq). The highest contribution to the ED was by the urinary bladder (2.5 ± 1.1 ”Sv/MBq), followed by the red marrow (1.7 ± 0.3 ”Sv/MBq) and the stomach (1.3 ± 0.4 ”Sv/MBq). According to this preclinical analysis, the ED to humans is 12.4 ”Sv/MBq when applying the ICRP103 tissue weighting factors. Taking into account that preclinical dosimetry underestimates the dose to humans by up to 40%, the conversion factor applied for estimation of the ED to humans would rise to 20.6 ”Sv/MBq. In this case, the ED to humans upon an iv application of ~300 MBq [18F]FACH would be about 6.2 mSv. This risk assessment encourages the translation of [18F]FACH into clinical study phases and the further investigation of its potential as a clinical tool for cancer imaging with PET
Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality
Strongly correlated quantum fluids are phases of matter that are
intrinsically quantum mechanical, and that do not have a simple description in
terms of weakly interacting quasi-particles. Two systems that have recently
attracted a great deal of interest are the quark-gluon plasma, a plasma of
strongly interacting quarks and gluons produced in relativistic heavy ion
collisions, and ultracold atomic Fermi gases, very dilute clouds of atomic
gases confined in optical or magnetic traps. These systems differ by more than
20 orders of magnitude in temperature, but they were shown to exhibit very
similar hydrodynamic flow. In particular, both fluids exhibit a robustly low
shear viscosity to entropy density ratio which is characteristic of quantum
fluids described by holographic duality, a mapping from strongly correlated
quantum field theories to weakly curved higher dimensional classical gravity.
This review explores the connection between these fields, and it also serves as
an introduction to the Focus Issue of New Journal of Physics on Strongly
Correlated Quantum Fluids: from Ultracold Quantum Gases to QCD Plasmas. The
presentation is made accessible to the general physics reader and includes
discussions of the latest research developments in all three areas.Comment: 138 pages, 25 figures, review associated with New Journal of Physics
special issue "Focus on Strongly Correlated Quantum Fluids: from Ultracold
Quantum Gases to QCD Plasmas"
(http://iopscience.iop.org/1367-2630/focus/Focus%20on%20Strongly%20Correlated%20Quantum%20Fluids%20-%20from%20Ultracold%20Quantum%20Gases%20to%20QCD%20Plasmas
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