bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of continental plateaus by channel injection: models designed to address constraints and thermomechanical consistency
Authors: Medvedev S. , Beaumont C. 
Published: April 2008

Abstract

Weak, possibly partially molten, middle crust may exist and deform by channel flow beneath continental plateaus, thereby significantly influencing their dynamics. The role of channel flows in the transition zone between the plateau and the foreland is, however, unclear. We develop successively more complete approximate models for the channel injection (CI) mode in which differential pressure pumps channel material from beneath the plateau into the transitional crust, which thickens it and widens the plateau. The motivation is to improve our understanding of the controls on the growth of continental plateaus and the interactions in the transition zone, and to gain more insight into the results of more complex numerical models. In model CI-1, a channel with constant viscosity and thickness exists in the transitional crust and the pumped material accretes/freezes above and below the channel. Although results compare favourably with the geometry of some natural examples, this model is incomplete because the connection between the transition zone and the plateau is not considered. Model CI-2 includes a decrease in channel viscosity when the channel depth exceeds a critical value,
D
*, a proxy for onset of melt weakening or low viscosities at high temperatures. The model completes the connection to the plateau, but relies on the arbitrary choice of
D
*. Model CI-3 is more physically based, and considers the channel viscosity and thickness to depend on temperature, calculated by an associated thermal model that includes radioactive self-heating, and advection of heat by channel material. This model demonstrates self-consistent plateau widening if the channel viscosity decreases at the critical temperature,
T
*. Acceptable comparisons with the topography of Tibet are achieved with transition zone viscosities that decrease from 10
19
−10
22
Pa s to subplateau values of 10
18
–10
19
Pa s, with
T
* of 700−750°C. Additional analyses and tests are used to determine the range of parameter values for which CI models are both internally consistent and compatible with observations. Additional modes of deformation in the transition zone, viscous thickening (VT) and plastic translation (PT), may also be important.
Ductile extrusion in continental collision zones: ambiguities in the definition of channel flow and its identification in ancient orogens
Authors: Jones R. R. , Holdsworth R. E. , Hand M. , Goscombe B. 
Published: April 2008

Abstract
Field characteristics of crustal extrusion zones include: high-grade metamorphism flanked by lower-grade rocks; broadly coeval flanking shear zones with opposing senses of shear; early ductile fabrics successively overprinted by semi-brittle and brittle structures; and localization of strain to give a more extensive deformation history within the extrusion zone relative to the flanking regions. Crustal extrusion, involving a combination of pure and simple shear, is a regular consequence of bulk orogenic thickening and contraction during continental collision. Extrusion can occur in response to different tectonic settings, and need not necessarily imply a driving force linked to mid-crustal channel flow. In most situations, field criteria alone are unlikely to be sufficient to determine the driving causes of extrusion. This is illustrated with examples from the Nanga Parbat-Haramosh Massif in the Pakistan Himalaya, and the Wing Pond Shear Zone in Newfoundland.
Did the Himalayan Crystallines extrude partially molten from beneath the Tibetan Plateau?
Authors: Harrison T. Mark 
Published: April 2008

Abstract

The hypothesis that the Himalayan crystalline core originated by ductile channel flow of partially molten mid-crust from beneath the Tibetan Plateau is critically reviewed. The proposal that widespread shallow anatexis exists beneath southern Tibet today is inconsistent with numerous observations (e.g. ‘bright spots’ restricted to a single rift and evidence that they represent aqueous fluids rather than molten silicate; the seismogenic southern Tibetan Moho;
3
He/
4
He data indicating the presence of mantle heat and mass in the rift valley; the likelihood that any melt present is due to late Neogene calc-alkaline magmatism; the lack of Tertiary migmatites in the crustal section exposed in the uplifted rift flank of the Yangbajain graben; the lack of Gangdese zircon xenocrysts in the Greater Himalayan Crystallines (GHC); and the broadly coherent stratigraphy in the GHC). Evidence advanced in support of this model is equally or better explained as resulting from localized Neogene calc-alkaline magmatism. A recently developed rapid denudation/channel flow model does explain key petrogenetic and thermochronological features of the Himalaya, but is inconsistent with several geological constraints, most notably the small portion of the collision front over which focused erosion has localized exposure of the GHC. It is concluded that no evidence has yet been documented that requires the existence of partially molten crust flowing in a channel from beneath the Tibetan Plateau to form the Himalaya.
Pulsed channel flow in Bhutan
Authors: Hollister L. S. , Grujic D. 
Published: April 2008

Abstract
We summarize our results from Bhutan and interpret the Greater Himalaya Sequence (GHS) of Bhutan, together with a portion of the underlying Lesser Himalaya Sequence, in the context of recently published channel flow models. For the GHS rocks now exposed in Bhutan the depth for beginning of muscovite dehydration melting (approximately 750°C at 11 kbar) and associated weakening of these rocks is constrained by geobarometry to be at about 35–45 km. The location of initial melting was down-dip and over 200 km to the north of Bhutan. Melt was produced and injected into ductilely deforming metamorphic rocks as they were extruded towards the south between the Main Central Thrust (MCT) and the South Tibetan Detachment zones. The lateral flow of low viscosity rocks at these depths occurred under southern Tibet between 22 Ma and 16 Ma. Subsequently, the channel rocks decompressed from 11 to 5 kbar (from 35 km to a depth of 15 km), but maintained high temperatures, between about 16 Ma and 13 Ma. The data from Bhutan are consistent with channel flow models if there were several pulses of channel flow. The first, between 22 and 16 Ma, produced the rock seen in the lower half of the GHS of Bhutan. A second pulse, which is cryptic, is inferred to have led to the uplift and exhumation of the MCT zone. A third, in central Bhutan, is exposed now as the hanging wall of the Kakhtang thrust, an out-of-sequence thrust that was active at 12–10 Ma. The latter two pulses likely broke around a plug at the head of the first pulse that was formed where the melt in the channel had solidified.
The Malashan gneiss dome in south Tibet: comparative study with the Kangmar dome with special reference to kinematics of deformation and origin of associated granites
Authors: Aoya M. , Wallis S. R. , Kawakami T. , Lee J. , Wang Y. , Maeda H. 
Published: April 2008

Abstract

Despite the importance of Tethys Himalayan or North Himalayan gneiss domes for discussing extrusive flow of the underlying Greater Himalayan Sequence, these metamorphic domes in general remain poorly documented. The main exception is the Kangmar dome. The Malashan metamorphic complex, a newly documented North Himalayan gneiss dome, is shown to have strong similarities with the Kangmar dome, suggesting that the North Himalayan gneiss domes have the following features in common: (i) Barrovian-type metamorphism with grade increasing towards a centrally located two-mica granite; (ii) the presence of two dominant ductile deformation stages, D
1
and D
2
, with D
2
showing an increasing strength towards the granite contacts; and (iii) the development of a strong D
2
foliation (gneissosity) in the outermost part of the granite cores. In addition, field and bulk-chemical studies show: (i) D
2
is associated with a dominant top-to-the-north sense of shear (in disagreement with the most recent kinematic studies in Kangmar dome); (ii) the deposition age of associated metasediments is upper Jurassic suggesting that the Malashan dome is located not at the base, but within the middle section of the Tethys Himalaya; and (iii) in contrast to the Kangmar granitic gneiss that is interpreted as Indian basement, three granitic bodies in Malashan all formed as young intrusive bodies during the Himalayan orogeny. These results suggest that the formation mechanism of the North Himalayan gneiss domes needs to be re-evaluated to test the rigidity of the hanging wall assumed in channel flow models.
Ground deformation at Campi Flegrei, Italy: implications for hazard assessment
Authors: Bellucci Francesca , Woo Judith , Kilburn Christopher R. J. , Rolandi Giuseppe 
Published: April 2008

Abstract

Campi Flegrei caldera, west of Naples in southern Italy, has an exceptional documented record of ground deformation from Roman times onwards. Systematic recording began in the nineteenth century. For earlier dates, information has been obtained from archaeological studies and from contemporary descriptions of the locations of buildings, usually Roman, with respect to sea-level. Especially important have been accounts related to the Serapis, a Roman market-place built in the second century
bc
and now incorporated within the modern town of Pozzuoli. The long-term patterns of ground deformation have conventionally been investigated on the premise that Campi Flegrei naturally tends to a state of static equilibrium. This study argues that, instead, the area naturally tends to a steady rate of subsidence, at about 17 mm a
−1
. After this background rate has been removed, the data indicate that a permanent uplift of some 33 m has occurred from Roman times (up until the present day: 2005 at the time of writing), attributable to the intrusion of 1.85 km
3
of magma, of which only 1% has been erupted. Uplift has occurred in three episodes, the third of which is still in progress. The behaviour can be interpreted in terms of the intermittent ascent of magma between a reservoir of
c.
10
2
–10
3
km
3
at depths of 8–15 km or greater, to a much smaller, shallower system at depths of about 3–4 km. Should the current pattern of deformation follow previous trends, uplift is expected to continue for another 80–90 years, during which time Campi Flegrei will be characterized by an elevated possibility of eruption.
Rapid karstic bypass flow in the unsaturated zone of the Yorkshire chalk aquifer and implications for contaminant transport
Authors: Allshorn S. J. L. , Bottrell S. H. , West L. J. , Odling N. E. 
Published: April 2008

Abstract
Tracer tests have been performed on the unsaturated zone of the East Yorkshire chalk aquifer, UK. Rapid tracer travel times through significant thicknesses of unsaturated chalk (15–38 m) indicate that bypass flow must occur through fractures. Transport processes in the unsaturated zone of the chalk aquifer thus have similarities to those in the vadose zone of more typically karstic limestone aquifers. Modelling of tracer breakthrough curves indicates that bypass flow is sufficiently rapid to significantly inhibit diffusional loss of tracer into the porous matrix of the chalk. The presence of rapid karstic bypass flow in the unsaturated zone of the chalk will limit the potential for attenuation of groundwater contaminants in this zone.
Feasibility of Using Oscillatory Catalytic Oxidation Phenomenon for Selective Carbon Monoxide Sensing
Authors: Torvela Heikki 
Published: April 2008

Tin dioxide based sensors with different additives were constructed and tested in air environment containing carbon
monoxide. Conductance oscillations were observed in samples containing palladium but not in those without.
Oscillations occurred at temperatures ranging from 150℃ to 320℃. Within this temperature region the range of CO
concentrations at which oscillations appeared became higher as the test temperature increased. The lowest CO
concentration at which oscillations were observed was 200 ppm and the highest 10000 ppm.By comparing sensor responses obtained in synthetic and ambient air it was concluded that water vapour has a
major influence on oscillations and increases the frequency. The ranges of CO concentrations in which oscillations
occurred at different temperatures, however, remained roughly the same in both environments. It was also noticed that
processing conditions had an influence on the oscillatory response characteristics of the sensors.
Thermal and Electrical Analysis of Solid Aluminium Capacitors
Authors: Dekker E. H.L.J. , Lasance C. J.M. 
Published: April 2008

The thermal properties of electronic components partly determine the reliability of electronic equipment.
For electrolytic capacitors, they also set the limits for the ripple current and voltage values.This article first discusses the voltage limits under various conditions of temperature, frequency and
polarity. Then the connection of ripple current to these parameters and to the capacitor′s resistance is
treated.An extensive analysis is made of the influence of heat conduction in the capacitor and the printed‐circuit
board, for metal‐cased as well as for epoxy‐coated pearl types. The study pays particular attention
to solid aluminium capacitors containing a manganese dioxide semiconductor. They have some
extraordinary properties: a temperature range of at least – 80 to + 175℃, and an appreciable reverse
voltage potential.These can be fully employed to improve the ripple‐current specification.
The Growth and Assessment of GaAs Epitaxial Layers Obtained FromGa‐As‐Bi Solutions
Authors: Kozlowski J. , Panek M. , Ratuszek M. , Tlaczala M. 
Published: April 2008

X‐Ray investigations of GaAs epitaxial layers obtained from Ga‐As‐Bi solutions with different amounts of
bismuth are presented. An equilibrium cooling and two phase technique for the deposition of the GaAs
epitaxial layers on semi‐insulating GaAs:Cr(100) substrates has been used.It has been observed that independently of the growing solution composition, the epitaxial layers were
single crystal of (100) crystallographic orientation. Bismuth and chromium were not identified as impurities in
the investigated layers although this may be due to the low sensitivity (0.1 at . %) of the x‐ray microprobe used.
Stability and Performance Characterization of Thick FilmMicroresistors
Authors: Ravi Shobha C. 
Published: April 2008

In recent years, interest in the performance of small dimension resistors has increased primarily due to the need
to reduce parasitic resistance in high frequency applications. This paper presents results on the characterization
of thick film microresistors, i.e. resistors of 80 × 80 mil to 10 × 10 mil dimension.The thickness, sheet resistance and temperature coefficient of resistance were dependent on the resistor
length, whereas, thermal ageing drift and the thermal cycling drift values did not exhibit any such dependence.With reasonable precautions and optimization of the manufacturing conditions highly stable and good
quality microresistors can be fabricated.
Protection of Photoanodes Against Photo‐Corrosion by Surface Deposition of Oxide Films: Criteria for Choosing the Protective Coating
Authors: Campet G. , Manaud J. P. , Puprichitkun C. , Sun Z. W. , Salvador P. 
Published: April 2008

Two strategies to solve the problem of instability of photoanodes against photocorrosion
have been explored. The photocorrosion of photoanodes generally occurs when
they enter the fabrication of efficient photoelectrochemical cells (i.e. showing high
values of the open circuit voltage and photocurrent density).One of these strategies consists of protecting the photoanode against photocorrosion
by a non‐conducting oxide film deposited on its surface. The oxide must have a
cationic valence band, or valence energy states, falling either above, or at the same
level as, the top of the valence band of the anode. The significant photocurrent
observed with the n‐GaAs/Sr0.98Na0.01Ce0.01TiO3 hybridelectrode structure confirms the validity of the model.The second possibility deals with the protection of the photoanode by a conducting
oxide film in which the carrier transport occurs, close to the Fermi level, via either a
partially filled band or a sufficiently high density of localized states. We have illustrated
this method of protection by depositing n‐SrTiO3 on n‐GaAs. The n‐SrTiO3 films have
the Fermi level pinned within the forbidden band by Ti:3d(t2g) energy states. The
corresponding electrochemical cells exhibit photoconversion efficiency as high as 18%
for an illumination of 5 mW/cm2.
Layout and Thermal Analysis of PowerDevices Using a PC/XC
Authors: Avaritsiotis J. N. , Eleftheriades G. 
Published: April 2008

Thermal analysis during the design process is an essential step towards the achievement of high reliability
in modern high density hybrid and integrated circuits. Thermal analysis is also essential for modern,
high density PCBs. Traditionally, a solution of the thermal problem is obtained by either the method
of finite differences or the method of finite elements. Both methods, however, require a fine 3‐D
partition of the substrate, leading to large systems of linear equations the solution of which demands
substantial computing power provided by number crunching machines and/or powerful computer work‐stations.The widespread use of personal computers, however, dictates the development of new approaches
to the thermal problems so that a design engineer can solve them in reasonable time with a PC. A new
treatment of steady‐state thermal analysis combined with a layout editor is proposed in this paper,
which makes use of the analytical solution for the temperature distribution in a single‐layer substrate
with heat sources on the surface, and having an isothermal bottom surface. In this way the mathematical
complexity of the problem is dramatically reduced allowing the thermal analysis of Multi Chip Modules
(M.C.M.s) and complex hybrid circuits with the use of a PC/XT or compatible.
The Properties of Screen Printed (Bi,Pb)‐Sr‐Ca‐Cu‐O Thick Films Based OnDecomposed Oxalate Powders
Authors: Hagberg J. 
Published: April 2008

The significance of powder and paste characteristics was studied in order to improve the morphology
and structure of superconducting (Bi,Pb)‐Sr‐Ca‐Cu‐O screen printed thick films. Powder with nominal
composition of Bi1.75Pb0.4Sr1.9Ca2.1Cu3.2Oy was prepared via the oxalate route and decomposed at 430 to
795℃. The decomposed powders were characterized by X‐ray diffraction, transmission electron microscopy
and specific surface area measurements. These studies showed a variation of specific surface
area from 16.5 to 0.9 m2/g and a variation of the average particle size from 100 nm to 800 nm in the
studied temperature interval. The phase structure showed three distinct temperature areas; between
430 to 620, 620 to 715, and at 795℃.Thick‐film pastes were made by the addition of an organic vehicle at 500, 620, 650 and 795℃ to
decompose annealed oxalate synthesized powders and, for comparison, the vehicle was also added to
sintered mixed‐oxide/carbonate‐based powder in weight ratios from 0.42 to 0.54:1. Films were screen
printed on single crystal MgO (100) substrates and melt annealed at 890 to 895℃ for 3 min and
subsequently, for prolonged diffusion, annealed at 852℃. After firing, the films were mainly composed
of the (001) textured (Bi,Pb)2Sr2Ca2Cu3Oy phase. The reference films, made from mixed oxide/carbonate powder, resembled the films based on oxalate powders decomposed at 795℃. Films based on oxalate
powders, decomposed at lower temperatures, were smoother and were able to carry noticeably higher
currents than films based on powders decomposed at higher temperatures.
Computer‐Based Study of MCP‐Coupled Active Filters for Structures Like FLF, SCF, CBQ, and LF
Authors: Mital Prem Bhushan , Kumar Umesh 
Published: April 2008

This paper deals with the problem of the realization of low sensitivity narrow BP active filter implementing
multiple critical pole approximation methods. Coupled active filter structures are also studied.The position of a MCP (multiple critical pole) transfer function containing multiple poles is realized
as FLF (Follow the Leader Feedback) and and remaining part as cascade. Further MCP transfer functions
are combined with CBQ (Coupled Biquads), SCF (Shifted Companion Form), and LF (Leap Frog)
structure.
Analytical and Practical Study of Coupled Multivibrators
Authors: Kumar Umesh , Mital P. Bhushan 
Published: April 2008

This paper investigates the dynamic behavior of a system of two multivibrators. It is shown that the
characteristics of synchronization states of multivibrators are coupled in a particular manner and their
approach to synchronization can be tackled analytically without approximations. This can be regarded
as an advancement, since most of the analytical work on coupled oscillators attain results only by
resorting to an approximate mathematical method.It has been shown that the results obtained for coupled multivibrators are similar to those of sinusiodai
oscillators.Such systems are important in the fields of theoretical biology, communication, radar system technology,
and coupled solar cells.
Design, Fabrication, and Comparative Study of Electronically Tunable Active Filters
Authors: Kumar Umesh , Mital P. Bhushan 
Published: April 2008

The Kerwin‐Huelsman Newcomb (KHN) biquad is the natural choice for use as a ‘universal’ filter building block out of the several existing 3‐amplifier biquadratic filter sections based on the two integrator loop or state variable realization of 2nd order systems. A modified version of the KHN
biquad, which is electronically tunable almost linearly over a decade range of center frequency, is
presented. For electronic tunability, instead of the direct use of a FET as a voltage variable resistance
to control the time constants of the integrators, a novel approach of using voltage‐controlled variable‐gain
amplifiers at the inputs of both the integrators and one immediately after the input signal has been
suggested. The circuit is suitable for use as a tunable universal filtering module and can be easily
digitally programmed.Comparative treatment of general tuning methods of active filters, and some methods of electronic
tuning of active filters are discussed. A brief description of tuning algorithms of active filters is also
given.
Analysis and Modeling of Depletion‐Mode MOS Transistors
Authors: Kumar Umesh 
Published: April 2008

Depletion mode MOSFETs are widely used in MOS—LSI/VLSI circuits as load elements. The main advantages offered by these devices are:Higher packaging density,Improved performance,Reduced power consumption, etc.Masuhara et. al (1972) developed a model for analysis of this device as an enhancement mode MOSFET. The model was adequate for analysis of lightly‐doped, shallow‐implanted channels. Subsequently, a more rigorous analysis was put forth by HAKEN for larger doping and deep channels. The analysis made by Edward and Marr did not simplify the non‐linear relationship between surface depletion region width and gate voltage. The model also did not account for the transconductance of the device in the three operating regimes.In this paper, the various models are briefly examined, and an attempt has been made for extraction of various parameters for obtaining the DC characteristics of these devices.