133 research outputs found
Intense tera-hertz laser driven proton acceleration in plasmas
No full textWe investigate the acceleration of a proton beam driven by intense tera-hertz (THz) laser field from a near critical density hydrogen plasma. Two-dimension-in-space and three-dimension-in-velocity particle-in-cell simulation results show that a relatively long wavelength and an intense THz laser can be employed for proton acceleration to high energies from near critical density plasmas. We adopt here the electromagnetic field in a long wavelength (0.33 THz) regime in contrast to the optical and/or near infrared wavelength regime, which offers distinct advantages due to their long wavelength (λ = 350 μ m), such as the λ 2 scaling of the electron ponderomotive energy. Simulation study delineates the evolution of THz laser field in a near critical plasma reflecting the enhancement in the electric field of laser, which can be of high relevance for staged or post ion acceleration. © 2016 Author(s)
Pulsed EM field, close-range signal transfer in layered configurations - A time-domain analysis
No full textTera-Hertz SensingMicrowave Sensing, Signals & System
Fourier Optics Field Representations for the Design of Wide Field-of-View Imagers at Sub-millimetre Wavelengths
No full textTera-Hertz Sensin
Far-field beam pattern technique for high pointing accuracy characterization of GUSTO HEB mixer arrays
No full textTera-Hertz SensingQCD/DiCarlo LabImPhys/Optic
THz and Mid Infrared (TERA-MIR) semiconductor materials: From microscopic theory to industrial applications
No full textThe author discusses the main goals and recent achievements of MPNS COST ACTION MP1204, TERA-MIR Radiation: Materials, Generation, Detection and Applications, whose main objectives are to advance novel materials, concepts and device designs for generating and detecting THz and Mid Infrared radiation using semiconductor, superconductor, metamaterials and lasers and to beneficially exploit their common aspects within a synergetic approach. The unique networking and capacity-building capabilities provided by the COST framework are used to unify these two spectral domains from their common aspects of sources, detectors, materials and applications. A platform is developed to investigate the interdisciplinary topics in Physics, Electrical Engineering and Technology, Applied Chemistry, Materials Sciences and Biology and Radio Astronomy. The main emphasis is on new fundamental material properties, concepts and device designs that are likely to open the way to new products or to the exploitation of new technologies in the fields of sensing, healthcare, biology, and industrial applications
La canción rodia de la golondrina y la cerámica de Tera
No full textThe song of the Swallow, attested by Athenaeus, which Rhodian children sung while collecting from house to house, is important for Greek religion and poetry. It has a choral part and then another part sung by the exarchon, who is identified as the swallow.
Probably the song is related to a ritual where the “swallow”, which arrives in Spring, unites in “hieros gramos” with a woman of the country. The song has preserved, in ludic from, elements of a song of “welcome” as well as of a “paraclausithyron”: its erotic charter is without any doubt. The song is compared with similar songs in Greece and the author proposes, for the fresco of the swallow and several vessels decorated with swallows found in Tera, a relation with a cult of the swallow, from which the song would proceed in last instauce.No disponible
Gas Turbine Application to CO2 Pipeline: A Techno-Economic and Environmental Risk Analysis
No full textGas Turbines (GTs) are used extensively in pipelines to compress gas at
suitable points. The primary objective of this study is to look at CO2 return
pipelines and the close coupling of the compression system with advanced
prime mover cycles.
Adopting a techno-economic and environmental risk analysis (TERA) frame
work, this study conducts the modelling and evaluation of CO2 compression
power requirements for gas turbine driven equipment (pump and compressor).
The author developed and validated subroutines to implement variable stators
in an in-house GT simulation code known as Variflow in order to enhance the
off-design performance simulation of the code. This modification was achieved
by altering the existing compressor maps and main program algorithm of the
code. Economic model based on the net present value (NPV) method, CO2
compressibility factor model based on the Peng-Robinson equation of state and
pipeline hydraulic analysis model based on fundamental gas flow equation were
also developed to facilitate the TERA of selected GT mechanical drives in two
case scenarios. These case scenarios were specifically built around
Turbomatch simulated GT design and off-design performance which ensure that
the CO2 is introduced into the pipeline at the supercritical pressure as well as
sustain the CO2 pressure above a minimum designated pressure during
transmission along an adapted real life pipeline profile.
The required compression duty for the maximum and minimum CO2 throughput
as well as the operation site ambient condition, guided the selection of two GTs
of 33.9 MW and 9.4 MW capacities. At the site ambient condition, the off design
simulations of these GTs give an output of 25.9 MW and 7.6 MW respectively.
Given the assumed economic parameters over a plant life of 25 years, the NPV
for deploying the 33.9 MW GT is about £13.9M while that of the 9.4 MW GT is
about £1.2M. The corresponding payback periods (PBPs) were 3 and 7 years
respectively. Thus, a good return on investment is achieved within reasonable
risk. The sensitivity analysis results show a NPV of about £19.1M - £24.3M and
about £3.1M - £4.9M for the 33.9 MW and 9.4 MW GTs respectively over a 25 -
50% fuel cost reduction. Their PBPs were 3 - 2 years and 5 - 4 years
respectively. In addition, as the CO2 throughput drops, the risk becomes higher
with less return on investment. In fact, when the CO2 throughput drops to a
certain level, the investment becomes highly unattractive and unable to payback
itself within the assumed 25 years plant life. The hydraulic analysis results for
three different pipe sizes of 24, 14 and 12¾ inch diameters show an increase in
pressure drop with increase in CO2 throughput and a decrease in pressure drop
with increase in pipe size for a given throughput. Owing to the effect of elevation
difference, the 511 km long pipeline profile gives rise to an equivalent length of
511.52 km. Similarly, given the pipeline inlet pressure of 15 MPa and other
assumed pipeline data, the 3.70 MTPY (0.27 mmscfd) maximum average CO2
throughput considered in the 12¾ inch diameter pipeline results in a delivery
pressure of about 15.06 MPa. Under this condition, points of pressure spikes
above the pipeline maximum operating allowable pressure (15.3 MPa) were
obtained along the profile. Lowering the pipeline operating pressure to 10.5
MPa gives a delivery pressure of about 10.45 MPa within safe pressure limits.
At this 10.5 MPa, over a flat pipeline profile of same length, the delivery
pressure is about 10.4 MPa. Thus, given the operating conditions for the dense
phase CO2 pipeline transmission and the limit of this study, it is very unlikely
that a booster station will be required. So also, compressing the CO2 to 15 MPa
may no longer be necessary; which eliminates the need of combining a
compressor and pump for the initial pressure boost in order to save power. This
is because, irrespective of the saving in energy, the increase in capital cost
associated with obtaining a pump and suitable driver far outweighs the extra
expense incurred in acquiring a rated GT mechanical drive to meet the
compression duty
Causal pulses with rectangular spectral content: a tool for TD analysis of uwb antenna performance
No full textTera-Hertz SensingElectrical Engineering, Mathematics and Computer Scienc
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