Focused resolution of thin conducting layers by various dipole EM systems

Geophysics ◽  
1995 ◽  
Vol 60 (2) ◽  
pp. 381-389 ◽  
Author(s):  
Saurabh Kumar Verma ◽  
S. P. Sharma
Keyword(s):  
Narrow Range ◽  
Conducting Layer ◽  
Good Resolution ◽  
Fixed Frequency ◽  
Electromagnetic Sounding ◽  
Maximum Resolution ◽  
Thin Conducting ◽  
Wide Range ◽  
Target Layer ◽  
Separation Parameters

Electromagnetic sounding in the frequency domain can be performed in two ways—either by changing frequency at a location (frequency sounding) or by changing the transmitter‐receiver (T-R) separation using a fixed frequency (geometric sounding). These changes in frequency or separation parameters effect vertical scanning of conductivity distributions below the earth’s surface. In case of thin conducting layers, there could be an optimum range of frequencies or T-R separations that provide maximum resolution of the layer parameters. Thus, for a given buried target layer, it should be possible to find ranges of frequencies or separations that yield the best focusing. The present study deals with the focused resolution of a thin conducting layer in frequency sounding with variable T-R separation for four different dipole configurations. It is observed from the inversion of the data from various dipole electromagnetic (EM) systems that different T-R separations have different resolutions for the same target layer. It is also observed that for a particular loop system, the best resolution is observed at an optimum T-R separation. The resolution becomes poorer when the T-R separation is either increased or decreased from this particular separation. Thus it has been possible to propose a “zone of focusing” for various dipole EM configurations. The study reveals that this zone is broadest for the horizontal coplanar loops system, implying that this system yields good resolution over a wide range of T-R separations. Compared to this, the perpendicular loops system yields a very sharp peak implying that it resolves the target over a very narrow range of separations. However, the perpendicular loops system provides resolution most parsimoniously requiring the least T-R separation. This is followed by the vertical coplanar, vertical coaxial, and horizontal coplanar loops systems.

Validated Stability Indicating HPTLC Method for the Estimation of Amoxapine in Different Stress Conditions

2019 ◽  
Vol 15 (3) ◽  
pp. 273-279
Author(s):  
Shweta G. Rangari ◽  
Nishikant A. Raut ◽  
Pradip W. Dhore
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Analysis Data ◽  
Peak Height ◽  
Good Resolution ◽  
Stability Indicating ◽  
Limit Of Quantitation ◽  
Wide Range ◽  
Hptlc Method

Background:The unstable and/or toxic degradation products may form due to degradation of drug which results into loss of therapeutic activity and lead to life threatening condition. Hence, it is important to establish the stability characteristics of drug in various conditions such as in temperature, light, oxidising agent and susceptibility across a wide range of pH values.Introduction:The aim of the proposed study was to develop simple, sensitive and economic stability indicating high performance thin layer chromatography (HPTLC) method for the quantification of Amoxapine in the presence of degradation products.Methods:Amoxapine and its degraded products were separated on precoated silica gel 60F254 TLC plates by using mobile phase comprising of methanol: toluene: ammonium acetate (6:3:1, v/v/v). The densitometric evaluation was carried out at 320 nm in reflectance/absorbance mode. The degradation products obtained as per ICH guidelines under acidic, basic and oxidative conditions have different Rf values 0.12, 0.26 and 0.6 indicating good resolution from each other and pure drug with Rf: 0.47. Amoxapine was found to be stable under neutral, thermal and photo conditions.Results:The method was validated as per ICH Q2 (R1) guidelines in terms of accuracy, precision, ruggedness, robustness and linearity. A good linear relationship between concentration and response (peak area and peak height) over the range of 80 ng/spot to 720 ng/spot was observed from regression analysis data showing correlation coefficient 0.991 and 0.994 for area and height, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) for area were found to be 1.176 ng/mL and 3.565 ng/mL, whereas for height, 50.063 ng/mL and 151.707 ng/mL respectively.Conclusion:The statistical analysis confirmed the accuracy, precision and selectivity of the proposed method which can be effectively used for the analysis of amoxapine in the presence of degradation products.

scholarly journals Subject-specific multiscale modeling of aortic valve biomechanics

2021 ◽  
Author(s):  
G. Rossini ◽  
A. Caimi ◽  
A. Redaelli ◽  
E. Votta
Keyword(s):  
Aortic Valve ◽  
Boundary Conditions ◽  
Narrow Range ◽  
Radial Strain ◽  
Length Scale ◽  
Length Scales ◽  
Anatomical Features ◽  
Wide Range ◽  
Subject Specific ◽  
Cell Strains

AbstractA Finite Element workflow for the multiscale analysis of the aortic valve biomechanics was developed and applied to three physiological anatomies with the aim of describing the aortic valve interstitial cells biomechanical milieu in physiological conditions, capturing the effect of subject-specific and leaflet-specific anatomical features from the organ down to the cell scale. A mixed approach was used to transfer organ-scale information down to the cell-scale. Displacement data from the organ model were used to impose kinematic boundary conditions to the tissue model, while stress data from the latter were used to impose loading boundary conditions to the cell level. Peak of radial leaflet strains was correlated with leaflet extent variability at the organ scale, while circumferential leaflet strains varied over a narrow range of values regardless of leaflet extent. The dependency of leaflet biomechanics on the leaflet-specific anatomy observed at the organ length-scale is reflected, and to some extent emphasized, into the results obtained at the lower length-scales. At the tissue length-scale, the peak diastolic circumferential and radial stresses computed in the fibrosa correlated with the leaflet surface area. At the cell length-scale, the difference between the strains in two main directions, and between the respective relationships with the specific leaflet anatomy, was even more evident; cell strains in the radial direction varied over a relatively wide range ($$0.36-0.87$$ 0.36 - 0.87 ) with a strong correlation with the organ length-scale radial strain ($$R^{2}= 0.95$$ R 2 = 0.95 ); conversely, circumferential cell strains spanned a very narrow range ($$0.75-0.88$$ 0.75 - 0.88 ) showing no correlation with the circumferential strain at the organ level ($$R^{2}= 0.02$$ R 2 = 0.02 ). Within the proposed simulation framework, being able to account for the actual anatomical features of the aortic valve leaflets allowed to gain insight into their effect on the structural mechanics of the leaflets at all length-scales, down to the cell scale.

Effects of Response Range in Frequency Judgments of Common versus Uncommon Events

1996 ◽  
Vol 82 (3_suppl) ◽  
pp. 1371-1376 ◽  
Author(s):  
Kimihiko Yamagishi
Keyword(s):  
Cognitive Processes ◽  
High Frequency ◽  
Narrow Range ◽  
Frequency Estimation ◽  
Low Frequency ◽  
Social Facts ◽  
Frequency Judgments ◽  
Response Range ◽  
Wide Range ◽  
Wide Condition

Frequency estimation of social facts was compared between two methods of response elicitation. In the “narrow range” method, respondents answered questions like: “Out of 100 instances, how many instances belong to category X?”. In the “wide range” method, the same question was asked regarding “Out of 10,000.” A previous study in 1994 showed that judged frequencies were proportionally greater in the narrow condition than in the wide condition when subjects estimated the occurrence of low-frequency events. These results were interpreted to reflect cognitive processes of anchoring, wherein judged frequencies he close to small numbers within particular response ranges. The current work extends this argument to high-frequency events. In such cases, judgments about high-frequency events would be reached by similar cognitive processes operating toward the opposite direction. Hence, I predicted that judged frequencies for high-frequency events would be proportionally greater in the wide than in the narrow condition. Results were mostly consistent with these predictions. The relation to previous research is discussed.

Fabrication of periodic microscale stripes of silver by laser interference induced forward transfer and their SERS properties

2021 ◽  
Author(s):  
Huijuan Shen ◽  
Yaode Wang ◽  
Liang Cao ◽  
Ying Xie ◽  
Lu Wang ◽  
...  
Keyword(s):  
Film Thickness ◽  
Laser Fluence ◽  
Nano Particles ◽  
Good Resolution ◽  
Laser Interference ◽  
Ag Nps ◽  
Wide Range ◽  
Forward Transfer ◽  
Stripe Structure ◽  
Average Size

Abstract The micro-stripe structure was prepared by laser interference induced forward transfer (LIIFT) technique, composed of Ag nano-particles (NPs). The effects of the film thickness with the carbon nano-particles mixed polyimide (CNPs@PI), Ag film thickness, and laser fluence were studied on the transferred micro-stripe structure. The periodic Ag micro-stripe with good resolution was obtained in a wide range of CNPs@PI film thickness from ~ 0.5 μm to ~ 1.0 μm for the Ag thin film ~ 20 nm. The distribution of the Ag NPs composing the micro-stripe was compact. Nevertheless, the average size of the transferred Ag NPs was increased from ~ 41 nm to ~ 197 nm with the change of the Ag donor film from ~ 10 nm to ~ 40 nm. With the increase of the laser fluence from 102 mJ•cm-2 to 306 mJ•cm-2 per-beam, the transferred Ag NPs became aggregative, improving the resolution of the corresponding micro-stripe. Finally, the transferred Ag micro-stripe exhibited the significant surface enhanced Raman scattering (SERS) property for rhodamine B (RhB). While the concentration of the RhB reached 10-10 mol•L-1, the Raman characteristic peaks of the RhB were still observed clearly at 622 cm-1, 1359 cm-1, and 1649 cm-1. These results indicate that the transferred Ag micro-stripe has potential application as a SERS chip in drug and food detection.

scholarly journals A biopsychosocial framework for recovery from COVID-19

2020 ◽  
Vol 40 (9/10) ◽  
pp. 1021-1039
Author(s):  
Kaz Stuart ◽  
Mark A. Faghy ◽  
Elaine Bidmead ◽  
Ruth Browning ◽  
Catriona Roberts ◽  
...  
Keyword(s):  
Living Arrangements ◽  
Design Methodology ◽  
Online Survey ◽  
Narrow Range ◽  
Analytical Framework ◽  
Content Type ◽  
Wide Range ◽  
Social Media Platforms ◽  
Practical Implications

PurposeThis paper proposes a biopsychosocial (BPS) analysis of COVID-19 experiences which enhances understanding of complex and interrelated factors and leads to the proposition of a BPS recovery framework.Design/methodology/approachOnline narrative research was used to explore people's experiences of COVID-19 and was conducted over a four-month period. The call was distributed via a short open-ended qualitative online survey advertised on social media platforms and 305 responses came from across England.FindingsThe findings illustrate people with a narrow range of BPS characteristics experienced over a wide range of BPS impacts which are nuanced, complex and dynamic. Left unaddressed these may create future adverse BPS characteristics. An integrated BPS framework for recovery is proposed to avoid such further negative outcomes from the pandemic.Research limitations/implicationsThe sample contained a bias in age, gender and living arrangements.Practical implicationsThe paper offers a clear framework to enable integrated holistic recovery/regrowth planning.Social implicationsUsing the framework would reduce social and health inequities which have been recently deepened by COVID-19 in the long-term.Originality/valueThe paper is original in its use of a BPS analytical framework.

scholarly journals The frequency of cortical microstimulation shapes artificial touch

2019 ◽  
Vol 117 (2) ◽  
pp. 1191-1200 ◽  
Author(s):  
Thierri Callier ◽  
Nathan W. Brantly ◽  
Attilio Caravelli ◽  
Sliman J. Bensmaia
Keyword(s):  
Neural Coding ◽  
Sensory Quality ◽  
Narrow Range ◽  
Low Frequencies ◽  
Pulse Trains ◽  
Sensation Magnitude ◽  
Frequency Judgments ◽  
Wide Range ◽  
Tactile Sensations

Intracortical microstimulation (ICMS) of the somatosensory cortex evokes vivid tactile sensations and can be used to convey sensory feedback from brain-controlled bionic hands. Changes in ICMS frequency lead to changes in the resulting sensation, but the discriminability of frequency has only been investigated over a narrow range of low frequencies. Furthermore, the sensory correlates of changes in ICMS frequency remain poorly understood. Specifically, it remains to be elucidated whether changes in frequency only modulate sensation magnitude—as do changes in amplitude—or whether they also modulate the quality of the sensation. To fill these gaps, we trained monkeys to discriminate the frequency of ICMS pulse trains over a wide range of frequencies (from 10 to 400 Hz). ICMS amplitude also varied across stimuli to dissociate sensation magnitude from ICMS frequency and ensure that animals could not make frequency judgments based on magnitude. We found that animals could consistently discriminate ICMS frequency up to ∼200 Hz but that the sensory correlates of frequency were highly electrode dependent: On some electrodes, changes in frequency were perceptually distinguishable from changes in amplitude—seemingly giving rise to a change in sensory quality; on others, they were not. We discuss the implications of our findings for neural coding and for brain-controlled bionic hands.

Influence of acute pulmonary vascular congestion on recoiling force of excised cats' lung

1959 ◽  
Vol 14 (6) ◽  
pp. 905-908 ◽  
Author(s):  
N. R. Frank
Keyword(s):  
Airway Pressure ◽  
Left Atrial ◽  
Technical Assistance ◽  
Narrow Range ◽  
Elastic Behavior ◽  
Tidal Breathing ◽  
Lung Volumes ◽  
Airway Pressures ◽  
Vascular Congestion ◽  
Wide Range

The effects of acute reversible pulmonary vascular congestion on the elastic behavior of excised cats' lungs were studied in 10 preparations. Measurements were made of changes in airway pressure at constantly held lung volumes over a wide range of deflation. To achieve vascular congestion left atrial pressure was raised to 20 and 30 cm H2O. Two effects were noted; one was that the slope of the volume-pressure relations of the lungs was slightly reduced at all levels of deflation, the other, the effect of vascular congestion on the recoiling force of the lungs was a function of the volume of the lungs at which congestion was induced. At large volumes (airway pressures of 5 cm H2O or more) recoiling force was increased; at intermediate volumes (airway pressures of 2.5 and 3 cm H2O) the change was negligible and, at smaller volumes, it was reduced in a manner consistent with the early work of von Basch. The findings suggest that there is a volume of the lungs, or perhaps a narrow range of volume, at which the lungs and blood vessels exert least mechanical stress on each other. This volume is believed to lie close to that in which tidal breathing occurs. Note: (With the Technical Assistance of Elcanor Gotz) Submitted on April 17, 1959

Responses of wheat to vernalization and photoperiod

1985 ◽  
Vol 36 (3) ◽  
pp. 347 ◽  
Author(s):  
JL Davidson ◽  
KR Christian ◽  
DB Jones ◽  
PM Bremner
Keyword(s):  
Flowering Time ◽  
Broad Spectrum ◽  
Narrow Range ◽  
Genetic Material ◽  
High Rainfall ◽  
Wide Range

The effects of vernalization and photoperiod on times from planting of seedlings to ear emergence were measured in 68 Australian and 49 overseas varieties of wheat, comprising a broad spectrum of genetic material, in a glasshouse in Canberra (latitude 35�S). Vernalization was carried out by growing germinated seedlings in the dark at 1-2�C for 6 weeks. Long photoperiods (16 h) separated unvernalized plants into two distinct groups, corresponding to commonly recognized spring and winter types. Responses to vernalization were generally small under natural photoperiods (11-15 h), but much more pronounced in long photoperiods, particularly with winter wheats. In a second experiment, 24 varieties of wheat gave widely different responses to vernalization treatments. With 8 weeks' vernalization and long photoperiods, all varieties reached ear emergence within 66 days, but in some winter wheats 4 weeks treatment had little effect and 6 weeks gave incomplete vernalization. Under the conditions of these experiments, Australian wheats showed a wide range of responses to photoperiod and a narrow range of responses to vernalization compared with overseas varieties. The need to investigate the control of flowering time in obtaining varieties suited to the high-rainfall zone of Australia is discussed.

Generation of Ultralow Tensions Over a Wide EACN Range Using Pennsylvania State U. Surfactants

1983 ◽  
Vol 23 (01) ◽  
pp. 73-80 ◽  
Author(s):  
E.E. Klaus ◽  
J.H. Jones ◽  
R. Nagarajan ◽  
T. Ertekin ◽  
Y.M. Chung ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Narrow Range ◽  
Carbon Number ◽  
Cyclic Ethers ◽  
Equivalent Weight ◽  
High Concentration ◽  
Low Concentration ◽  
Surfactant Solutions ◽  
Wide Range

Klaus, E.E., Pennsylvania State U. Jones, J.H., Pennsylvania State U. Nagarajan, R., Pennsylvania State U. Ertekin, T., SPE. Pennsylvania State U. Chung, Y.M., Pennsylvania State U. Arf, G., Pennsylvania State U. Yarzumbeck, A.J., Pennsylvania State U. Dudenas, P., Pennsylvania State U. Abstract Saturated paraffinic and naphthenic hydrocarbons without aromatics have been vapor-phase oxidized to produce cyclic ethers and lesser amounts of olefins. These cyclic ethers appear to be effective cosurfactants for the preparation of slugs containing petroleum sulfonate surfactants. The cyclic-ether/olefin mixture has been reacted with SO from oleum or liquid SO to form sulfonates comprising a mixture of mono-, di-, and polysulfonates. The reaction products consisting of the sulfonates, unreacted oxidized products, and residual hydrocarbons have been extracted with isopropanol (IPA) to give two sulfonate fractions. The first fraction is predominantly monosulfonate with lesser quantities of disulfonates. The second fraction consists primarily of di-, tri-, and polysulfonates. The monosulfonate fraction in a low-concentration slug exhibits ultralow interfacial tension (IFT) against hydrocarbons of low equivalent alkane carbon number (EACN). The behavior of this fraction is similar to that of the commercial sulfonates in that its ability to generate low IFT is confined to a narrow range of EACN. To achieve low IFT's at higher EACN in the range of a Pennsylvania crude oil, it is necessary to raise the equivalent weight of the Pennsylvania State U. monosulfonate fraction by blending with a commercial sulfonate of higher equivalent weight. Recent studies show that by mixing, the two IPA fractions of the sulfonation products. a remarkably new surfactant behavior is obtained. In contrast to the behavior of other surfactants that yield ultralow tensions over only a narrow range of values of EACN, this mixture of mono- and polysulfonates generates low IFT's over a wide range of EACN extending from C5 to C12. The salt tolerance of monosulfonates and polysulfonates, either alone or in mixtures. is rather high and even at about 4 wt% NaC1, the surfactant solutions remain stable and yield low IFT's against crude oil. Introduction Chemical flooding processes for terliary oil recovery based on both low-concentration surfactant solutions (typically 2 to 3 wt% or less) and high-concentration surfactant solutions (about 10 wt%) are being investigated in a number of laboratory and field studies. In both types of processes, the ability of surfactant solutions to lower the IFT against crude oil is a major factor determining the oil displacement efficiency. A variety of surfactants, primarily sulfonates synthesized from aromatics present in petroleum fractions, have been identified as those possessing the physical and chemical properties required for the flooding process. The surfactant slug formulations typically consist of the sulfonates, electrolytes, and cosurfactants such as alcohols. The slug, when contacted with oil, can generate a microemulsion phase coexisting with oil and water phases. Low IFT's are found to occur at those conditions that favor the formation of the preceding three phases. Several investigations have focused on determining the conditions for the three- phase formation and IFT lowering in terms of the molecular structure and the molecular weight of the surfactant, the characteristics of the oil (namely, its EACN), salinity, surfactant concentration, and the type and amount of cosurfactant, if used. SPEJ P. 73^

scholarly journals Quantitative Analysis of Walking in a Decapod Crustacean, the Rock Lobster Jasus Lalandii: II. Spatial and Temporal Regulation of Stepping in Driven Walking

1983 ◽  
Vol 107 (1) ◽  
pp. 219-243 ◽  
Author(s):  
C. CHASSERAT ◽  
F. CLARAC
Keyword(s):  
Narrow Range ◽  
Decapod Crustacean ◽  
Power Stroke ◽  
Careful Study ◽  
Rock Lobster ◽  
Return Stroke ◽  
Temporal Regulation ◽  
Belt Speed ◽  
Precise Adjustment ◽  
Wide Range

Spatial and temporal stepping parameters have been studied in a rocklobster walking on a treadmill moving at a wide range of speeds. The stride and the return stroke (RS) duration remain more or less stable and independent of the belt speed. Nevertheless, these ‘invariant’ parameters can act as spatial and temporal buffers resulting in a very precise adjustment of individual steps. A careful study of the power stroke (PS) duration demonstrates that the rock-lobster, although constrained to walk at an imposed belt speed, continues to correct its leg speed over a narrow range when the speed is considerably different from its natural one. Ipsilateral phases are always speed dependent, with an interleg ascending delay that is almost constant. The contralateral phase between legs of the same pair is approximately constant. Some of the parameters described are greatly influenced by gradual or abrupt variations in the belt speed. For a given speed, there is no absolute significance in the step period and ipsilateral phase. At very slow speeds, the interleg relations are significantly changed and have been studied separately. The metachrony observed at other speeds is discussed in relation to data from other arthropods.

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