CyberKnife reference dosimetry: An assessment of the impact of evolving recommendations on correction factors and measured dose

2020 ◽  
Vol 47 (8) ◽  
pp. 3573-3585
Author(s):  
Nicole Buchegger ◽  
Garry Grogan ◽  
Ben Hug ◽  
Chris Oliver ◽  
Martin Ebert
Keyword(s):  
Correction Factors ◽  
Measured Dose ◽  
The Impact

scholarly journals A new approach to radon temporal correction factor based on active environmental monitoring devices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Dicu ◽  
B. D. Burghele ◽  
M. Botoş ◽  
A. Cucoș ◽  
G. Dobrei ◽  
...  
Keyword(s):  
Radon Concentration ◽  
Residential Buildings ◽  
Indoor Radon ◽  
Smart Device ◽  
Correction Factors ◽  
Indoor Radon Concentration ◽  
Radon Measurements ◽  
The Impact ◽  
Monitoring Devices ◽  
Temporal Correction

AbstractThe present study aims to identify novel means of increasing the accuracy of the estimated annual indoor radon concentration based on the application of temporal correction factors to short-term radon measurements. The necessity of accurate and more reliable temporal correction factors is in high demand, in the present age of speed. In this sense, radon measurements were continuously carried out, using a newly developed smart device accompanied by CR-39 detectors, for one full year, in 71 residential buildings located in 5 Romanian cities. The coefficient of variation for the temporal correction factors calculated for combinations between the start month and the duration of the measurement presented a low value (less than 10%) for measurements longer than 7 months, while a variability close to 20% can be reached by measurements of up to 4 months. Results obtained by generalized estimating equations indicate that average temporal correction factors are positively associated with CO2 ratio, as well as the interaction between this parameter and the month in which the measurement took place. The impact of the indoor-outdoor temperature differences was statistically insignificant. The obtained results could represent a reference point in the elaboration of new strategies for calculating the temporal correction factors and, consequently, the reduction of the uncertainties related to the estimation of the annual indoor radon concentration.

C-130H Centre Wing Lower Surface Tang Blend Repair Management

2014 ◽  
Vol 891-892 ◽  
pp. 1071-1076
Author(s):  
Ross Stewart ◽  
Alvin Ng ◽  
Stuart Trezise ◽  
Phillip East ◽  
Kevin Jackson
Keyword(s):  
Finite Element ◽  
Management Strategy ◽  
Damage Tolerance ◽  
Element Model ◽  
Lower Surface ◽  
Correction Factors ◽  
Worst Case ◽  
Damage Maps ◽  
Management Advice ◽  
The Impact

The RAAF found significant corrosion on the C-130H fleet Centre Wing Lower Surface (CWLS) panels at the tangs adjacent to the rainbow fittings. Repair of this corrosion involves blends and spot facing, and often requires the addition of a doubler to reinforce the region. All RAAF C-130H aircraft had various combinations of spot faces, blends and in some cases doublers at this location. Due to the number and combination of repairs, providing fleet wide management advice is problematic. The fleet condition was assessed from damage maps, repairs and previous analyses. From this a number of worst case configurations were determined. A Finite Element Model was developed and used to determine the bearing and by-pass loads in each fastener row of the panel tangs. Stress intensity correction factors were developed for cracks growing from or to a spot face using Stress Check. These correction factors were applied on top of geometry factors for the baseline configuration. A Damage Tolerance Assessment (DTA) was performed to assess the impact of spot face and blend repairs on the centre wing lower surface panel tangs, in order to develop a fleet wide management strategy. Based on the results for the repair cases, it was shown that the repairs identified in the damage maps could be managed within the existing safety by inspection program.

The impact of inter-unit variations on small field dosimetry correction factors, with application to the CyberKnife system

2019 ◽  
Vol 64 (3) ◽  
pp. 035006 ◽  
Author(s):  
P Francescon ◽  
W Kilby ◽  
N Satariano ◽  
C Orlandi ◽  
S Elshamndy
Keyword(s):  
Small Field ◽  
Correction Factors ◽  
Small Field Dosimetry ◽  
The Impact

scholarly journals The influence of Gas Type on a Thermal Mass Flowmeter Calibration Results

2019 ◽  
Author(s):  
Oras ABBAS ◽  
Fabrice Mouchel
Keyword(s):  
Gas Injection ◽  
Thermal Mass ◽  
Actual Process ◽  
Correction Factors ◽  
Process Gas ◽  
K Factor ◽  
Multiple Process ◽  
Process Gases ◽  
Sweeping Gas ◽  
The Impact

The Thermal Mass Flowmeters (TMFMs) have been used for more than twenty years in the industry for various uses, including sweeping, gas injection, and welding. Their operational behaviors are still not well understood by operators. TMFMs, could be used with multiple process gases, and sometimes, highly toxic gases and they are generally calibrated with nitrogen or air. In the case of using a surrogate gas for calibration, a correction factor (k-factor) is required to estimate the flow of the process gas. Most of the time, these correction factors are indicated in the manufacturer’s instructions manual. In the field of metrology, k-factor plays a significant role in calibration results. Therefore, it is important to understand the influence of gas type used in calibration on the results if the process gas is employed or a surrogate gas with the recommended k-factor. The aim of this paper therefore is to discuss and evaluate the impact of using manufacturers k-factor in place of the actual process gas during calibration. The tests results presented within this article are considered concerning within the field of metrology.

A combined model approach for debris-flow impact forces

2021 ◽  
Author(s):  
Lukas Reider ◽  
Anna-Lisa Fuchs ◽  
Lisa Dankwerth ◽  
Susanna Wernhart ◽  
Roland Kaitna ◽  
...  
Keyword(s):  
Debris Flow ◽  
Correction Factor ◽  
Debris Flows ◽  
Flow Behaviour ◽  
Material Composition ◽  
Correction Factors ◽  
Additional Pressure ◽  
Impact Forces ◽  
Pressure Term ◽  
The Impact

<p>For the design of mitigation measures knowledge of debris-flow impact forces, usually estimated based on hydrostatic, hydrodynamic, or combined approaches, is essential. As these approaches are based on Newtonian fluids, they must be adjusted by empirical correction factors to account for the solid-fluid nature of debris flows. The values for the correction factors shown in the literature vary over a wide range and several studies showed a clear dependence with the Froude regime of debris flows.</p><p>To better understand the correction factors and to be able to calculate them using parameters that describe the flow behaviour a total of 32 experiments were conducted in the course of the project “Debris flow impact forces on bridge super structures (DEFSUP)”, funded by the Austrian Science Fund (FWF). Two different material compositions, different water contents as well as a total impact and a bypassing of the measuring block were tested.</p><p>The experimental setup designed within the project consists of a 4 m long semi-circular channel with a diameter of 300 mm and an inclination of 20°. The material is released from a rectangular reservoir in a dam-break scenario and accelerated with zero roughness on a length of 1.2 m and transferred to the semi-circle profile. The subsequently introduced roughness with a grain diameter of 1-2 mm generates a stationary phenomenological debris flow until it hits the measuring setup. With a starting volume of 50 kg, flow heights between 8 and 12 cm and velocities from 0.8 to 2.2 m/s were achieved according to the material composition and different water content. With these different mixtures a Froude-range from 0.6 to 3.6 was covered. In addition, normal stresses and pore water pressures were measured at the exact same point.</p><p>A detailed analysis of the measured impact forces together with the above mentioned measured parameters showed that the hydrodynamic correction factor is a constant mainly corresponding to the liquification ratio of the debris-flow mixture. Hence, the hydrodynamic correction factor can be regarded as a drag coefficient and seems to depend mainly on the internal friction of the flowing medium. At low Froude numbers measured impact forces exceed even a full momentum transfer if the mean bulk density is used for the calculation. This indicates that the impact forces can no longer be described by the hydrodynamic approach alone. For this reason, an additional pressure term based on a hydrostatic approach is considered in the combined concept. This additional pressure term depends on the dynamics of flow (Froude number) and can be modelled via a dynamic earth pressure coefficient.</p><p>The findings from these experiments contribute to a better prediction of debris-flows impact forces in terms of their material composition and flow behaviour.</p>

The Influence of Experimental Errors on the Correction Parameters of Finite Element Models

1997 ◽  
Author(s):  
Stefan Keye
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Numerical Models ◽  
Element Model ◽  
Finite Element Models ◽  
Correction Factors ◽  
Modal Data ◽  
Experimental Errors ◽  
Measurement Uncertainties ◽  
The Impact

Abstract A simulation study has been performed on the influence of experimental errors on the accuracy of finite element model corrections. The impact of measurement uncertainties on the sub-structure correction factors, natural frequencies, and mode shape correlation is investigated using simulated modal data. Different numerical models are used to assess the effects of modelization error magnitudes and locations.

Thermal Performance Prediction for High Power Processors at High Altitude

2005 ◽  
Author(s):  
Guoping Xu
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Thermal Performance ◽  
High Power ◽  
Air Flow ◽  
Measurement Data ◽  
Correction Factors ◽  
Flow Impedance ◽  
Impedance Curve ◽  
The Impact

A method to predict high power processor thermal performance in air-cooled electronic systems at high altitude is proposed in this paper. This method employs non-dimensional heat transfer and fluid flow parameters to evaluate the impact of high altitude conditions based on measurement data at sea level. Experimental data including fan/fan tray curve, system air flow impedance and processor heat sink performance for various air flow rates at sea level are required for the analysis. Altitude correction factors will be derived from nondimensional correlations. By using these altitude correction factors, the dimensional fan curve, system air flow impedance curve, and thermal performance curve may all be transformed from sea-level to high altitude. The proposed method can be applied to thermal performance predictions of forced convection electronic components with or without air-cooled heat sinks. The method can be used in a system with any flow regime: laminar, turbulent or a combination of both. This method will be demonstrated through an example of a high end server system.

scholarly journals CARRYING CAPACITY ASSESSMENT OF CIBEUREUM WATERFALLTOURISMINGUNUNG GEDE PANGRANGO NATIONAL PARK

2021 ◽  
Vol 25 (3) ◽  
pp. 203-211
Author(s):  
Anindika Putri Lakspriyanti ◽  
Meti Ekayani ◽  
Arzyana Sunkar
Keyword(s):  
Carrying Capacity ◽  
National Park ◽  
Management Strategy ◽  
Environmental Damage ◽  
Correction Factors ◽  
Nature Tourism ◽  
Tourism Management ◽  
Ticket Prices ◽  
Management Alternatives ◽  
The Impact

Waterfall has long been a popular tourist attraction with increasing number of visitors. High visitation would increase the risk of environmental damage, especially if the location of the tourism object is in a protected area that is still intact and rich in resources. One strategy to reduce the impact of recreational and nature tourism activities is through carrying capacity (CC) analysis. This study aims to 1) analyze the CC visitors of Cibeureum Waterfall and 2) provide a CC-based waterfall tourism management strategy. The research was conducted in October 2018 in Cibeureum Waterfall, TNGGP of West Java. The CC was estimated using the Cifuentes (1992) approach to calculate physical (PCC), real (RCC), and effective (ECC) CCs, by considering various correction factors. Interviews were also conducted with 100 visitors of Cibeureum Waterfall. In addition, interviews were also conducted with 5 key informants from the management side. The results showed that the daily PCC value was 800, exceeding the RCC (173) and ECC (86) values, indicating overcrowding. On the contrary, on weekdays, the number of visitors is below the RCC. These results indicated potential disturbance in Cibeureum Waterfall and its environment during holidays. Carrying capacity-based management alternatives that were recommended include increasing ticket prices on holidays and implement early booking system. From the managerial aspect, it is recommended to involve the NP partners during holidays for in-kind contributions. Keywords: carrying capacity, waterfall tourism, national park

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