Improved convective ice microphysics parameterization in the NCAR CAM model

2021 ◽  
Author(s):  
Lin Lin ◽  
Qiang Fu ◽  
Xiaohong Liu ◽  
Yunpeng Shan ◽  
Scott E. Giangrande ◽  
...  
Keyword(s):  
Ice Microphysics ◽  
Cam Model

scholarly journals Practical method for the fast generation of a CAM model for jet engine parts

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110027
Author(s):  
Byung Chul Kim ◽  
Ilhwan Song ◽  
Duhwan Mun
Keyword(s):  
Computer Aided Design ◽  
Feature Recognition ◽  
Practical Method ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Jet Engine ◽  
Computer Aided ◽  
Cad Models ◽  
Cam Model

Manufacturers of machine parts operate computerized numerical control (CNC) machine tools to produce parts precisely and accurately. They build computer-aided manufacturing (CAM) models using CAM software to generate code to control these machines from computer-aided design (CAD) models. However, creating a CAM model from CAD models is time-consuming, and is prone to errors because machining operations and their sequences are defined manually. To generate CAM models automatically, feature recognition methods have been studied for a long time. However, since the recognition range is limited, it is challenging to apply the feature recognition methods to parts having a complicated shape such as jet engine parts. Alternatively, this study proposes a practical method for the fast generation of a CAM model from CAD models using shape search. In the proposed method, when an operator selects one machining operation as a source machining operation, shapes having the same machining features are searched in the part, and the source machining operation is copied to the locations of the searched shapes. This is a semi-automatic method, but it can generate CAM models quickly and accurately when there are many identical shapes to be machined. In this study, we demonstrate the usefulness of the proposed method through experiments on an engine block and a jet engine compressor case.

scholarly journals The Estimation of Hydrometeor Profiles from Wideband Microwave Observations

2000 ◽  
Vol 39 (10) ◽  
pp. 1645-1656 ◽  
Author(s):  
Gail M. Skofronick-Jackson ◽  
James R. Wang
Keyword(s):  
High Frequency ◽  
Cloud Water ◽  
Tropical Ocean ◽  
Low Frequencies ◽  
High Frequencies ◽  
Atmospheric Research ◽  
Brightness Temperatures ◽  
Microphysical Properties ◽  
Ice Microphysics ◽  
Updraft Region

Abstract Profiles of the microphysical properties of clouds and rain cells are essential in many areas of atmospheric research and operational meteorology. To enhance the understanding of the nonlinear and underconstrained relationships between cloud and hydrometeor microphysical profiles and passive microwave brightness temperatures, estimations of cloud profiles for an anvil region, a convective region, and an updraft region of an oceanic squall were performed. The estimations relied on comparisons between radiative transfer calculations of incrementally estimated microphysical profiles and concurrent dual-altitude wideband brightness temperatures from the 22 February 1993 flight during the Tropical Ocean and Global Atmosphere Coupled Ocean–Atmosphere Response Experiment. The wideband observations (10–220 GHz) are necessary for estimating cloud profiles reaching up to 20 km. The low frequencies enhance the rain and cloud water profiles, and the high frequencies are required to detail the higher-altitude ice microphysics. A microphysical profile was estimated for each of the three regions of the storm. Each of the three estimated profiles produced calculated brightness temperatures within ∼10 K of the observations. A majority of the total iterative adjustments were to the estimated profile’s frozen hydrometeor characteristics and were necessary to match the high-frequency calculations with the observations. This requirement indicates a need to validate cloud-resolving models using high frequencies. Some difficulties matching the 37-GHz observation channels on the DC-8 and ER-2 aircraft with the calculations simulated at the two aircraft heights (∼11 km and 20 km, respectively) were noted, and potential causes were presented.

scholarly journals The Lagrangian ice microphysics code LCM: Introduction, current developments and benefits

2020 ◽  
Author(s):  
Simon Unterstrasser
Keyword(s):  
Crystal Growth ◽  
Turbulent Dispersion ◽  
Eddy Simulation ◽  
Ice Nuclei ◽  
Large Eddy ◽  
Radiative Impact ◽  
Ice Microphysics ◽  
Microphysical Processes ◽  
Aerosol Module ◽  
Les Model

<p>The Lagrangian Cirrus Module (LCM) is a Lagrangian (also known as particle-based) ice microphysics code that is fully coupled to the large-eddy simulation (LES) code EULAG. The ice phase is described by a large number of simulation particles (order 10<sup>6</sup> to10<sup>9</sup>) which act as surrogates for the real ice crystals. The simulation particles (SIPs) are advected and microphysical processes like deposition/sublimation and sedimentation are solved for each individual SIP. More specifically, LCM treats ice nucleation, crystal growth, sedimentation, aggregation, latent heat release, radiative impact on crystal growth, and turbulent dispersion. The aerosol module comprises an explicit representation of size-resolved non-equilibrium aerosol microphysical processes for supercooled solution droplets and insoluble ice nuclei.</p><p>First, an general introduction to particle-based microphysics coupled to a grid-based (Eulerian) LES model is given.<br>In the following, emphasis is put on highlighting the benefits of the Lagrangian approach by presenting a variety of simulation examples.</p>

scholarly journals THE IMPACT OF AGEING ON THE BITUMEN STIFFNESS MODULUS USING THE CAM MODEL

2018 ◽  
Vol 13 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Małgorzata CHOLEWIŃSKA ◽  
Marek IWAŃSKI ◽  
Grzegorz MAZUREK
Keyword(s):  
Complex Modulus ◽  
Surface Active Agent ◽  
Active Agent ◽  
Age Hardening ◽  
Fatty Amine ◽  
Modified Bitumen ◽  
Stiffness Modulus ◽  
The Impact ◽  
Cam Model

This article presents the results of the viscoelastic properties of the polymer-modified bitumen produced in Warm Mix Asphalt technology. A Fischer-Tropsch synthetic wax and a liquid surface-active agent (fatty amine) were used as bitumen viscosity-reducing modifiers. All tested parameters were determined after short-term and long-term ageing. The complex modulus G* and phase angle δ were measured with a cone-plate rheometer. All dynamic tests were performed at 60 °C within the frequency range from 0.005 Hz to 10 Hz. On the basis of the rheological index R determined using the Christensen−Anderson−Marasteanu (CAM) model, it was found that the fatty amine additive slowed down the age-hardening process in the bitumen. In contrast, the synthetic wax increased the stiffness of the bitumen at all levels tested, regardless of the type of ageing simulation process.

Advantages and limitations on combining radar dual - wavelength and polarimetric observations for ice microphysics retrievals

2021 ◽  
Author(s):  
Eleni Tetoni ◽  
Florian Ewald ◽  
Gregor Möller ◽  
Martin Hagen ◽  
Tobias Zinner ◽  
...  
Keyword(s):  
Dual Wavelength ◽  
Shape Estimation ◽  
Radar Observations ◽  
Microphysical Properties ◽  
Aspect Ratios ◽  
Retrieval Scheme ◽  
Mass Size ◽  
Ice Microphysics ◽  
German Aerospace ◽  
Size Relation

<p>The challenge of the ice microphysical processes representation in numerical weather models is a well-known phenomenon as it can lead to high uncertainty due to the variety of ice microphysics. As ice microphysical properties can strongly affect the initiation of precipitation as well as the type and amount of it, we need to better understand the complexity of ice processes. To accomplish this, better microphysics information through ice retrievals from measurements is needed. The multi-wavelength radar method is nowadays becoming more and more popular in such microphysics retrievals. Taking advantage of different scattering regimes (Rayleigh or Mie), information about the size of atmospheric hydrometeors can be inferred using different radar bands. For this study, dual-wavelength reflectivity ratio measurements were combined with polarimetric measurements to estimate the size of ice hydrometeors. The measurements were obtained by using the synergy of the C-band POLDIRAD weather radar from the German Aerospace Center, located in Oberpfaffenhofen, and the Ka-band MIRA-35 cloud radar from the Ludwig Maximilian University of Munich. Along with the dual-wavelength dataset, the Differential Reflectivity (Z<sub>DR</sub>) from POLDIRAD was used as a polarimetric contribution for the shape estimation of the detected ice particles. The radar observations were compared with T-matrix scattering simulations for the development of a retrieval scheme of ice microphysics. In the course of these studies, different assumptions were considered in the simulations. To capture the size variability, a Gamma particle size distribution (PSD) with different values of median volume diameter (MVD) was used. The soft spheroid approximation was used to approximate the ice particle shapes and to simplify the calculation and variation of their aspect ratios and effective densities. The selection of the most representative mass-size relation was the most crucial for the scattering simulations. In this study, we explored the modified Brown and Francis as well as the aggregates mass-size relation. After comparing the simulations to radar observations, we selected the better fitting one, i.e. aggregates, excluding the Brown and Francis as the simulated particles appeared to be too fluffy. Using the aggregates formulas, Look-Up tables (LUTs) for MVD, aspect ratio, and IWC were developed and used in the ice microphysics retrieval scheme. Here, we present preliminary microphysics retrievals of the median size, shape, and IWC of the detected hydrometeors combining the simulations in LUTs with the radar observations from different precipitation events over the Munich area.</p>

The chick embryo chorioallantoic membrane model: a research approach for ex vivo and in vivo experiments

2021 ◽  
Vol 28 ◽  
Author(s):  
Ana Isabel Fraguas-Sánchez ◽  
Cristina Martín-Sabroso ◽  
Ana Isabel Torres-Suárez
Keyword(s):  
Animal Models ◽  
Chorioallantoic Membrane ◽  
New Drugs ◽  
Biological Research ◽  
Research Areas ◽  
Chick Chorioallantoic Membrane ◽  
Biodistribution Studies ◽  
Toxicological Studies ◽  
Cam Model

Background: The chick chorioallantoic membrane (CAM) model has attracted a great deal of interest in pharmaceutical and biological research as an alternative or complementary in vivo assay to animal models. Traditionally, CAM assay has been widely used to perform some toxicological studies, specifically to evaluate the skin, ocular and embryo toxicity of new drugs and formulations, and perform angiogenesis studies. Due to the possibility to generate the tumors onto the CAM, this model has also become an excellent strategy to evaluate the metastatic potential of different tumours and test the efficacy of novel anticancer therapies in vivo. Moreover, in the recent years, its use has considerably grown in other research areas, including the evaluation of new anti-infective agents, the development of biodistribution studies and tissue engineering research. Objectives: This manuscript provides a critical overview of the use of CAM model in pharmaceutical and biological research, especially to test the toxicity of new drugs and formulations and the biodistribution and the efficacy of novel anticancer and anti-infective therapies, analyzing its advantages and disadvantages compared to animal models. Conclusion: The chick chorioallantoic membrane model shows great utility in several research areas, such as cancer, toxicology, biodistribution studies and anti-infective therapies. In fact, it has become an intermediate stage between in vitro experiments and animal studies, and, in the case of toxicological studies (skin and ocular toxicity), has even replaced the animal models.

Metastatic potential of MDA435 and Hep2 cell lines in chorioallantoic membrane (CAM) model

2001 ◽  
Author(s):  
Ilana Teruszkin Balassiano ◽  
Sheila Alves de Paulo ◽  
Nathalie Henriques Silva ◽  
Maulori Curie Cabral ◽  
Maria da Gloria da Costa Carvalho
Keyword(s):  
Cell Lines ◽  
Chorioallantoic Membrane ◽  
Metastatic Potential ◽  
Hep2 Cell ◽  
Cam Model

Deciphering the Myth About Non-Compliance and Its Impact on Cyber Security and Safety

2020 ◽  
pp. 59-72
Author(s):  
Kwasi Danso Dankwa
Keyword(s):  
Cyber Security ◽  
Health Centre ◽  
Assessment Model ◽  
Competitive Market ◽  
Safety Measures ◽  
Security Breaches ◽  
Security Incidents ◽  
Cam Model ◽  
Compliance Behaviour

The use of computers and sophisticated technologies are on the rise, and organizations are constantly looking for ways to invest in technologies to stay ahead of the competitive market. As such, cyber security and safety measures have been put in place by the organizations to protect them from attacks and to ensure that products and services are safe. However, managing cyber security and safety is becoming more challenging in today's business because people are both a cause of cyber security incidents as well as a key part of the protection from them. It is however that non-compliance with policies and directives are major security breaches. What is not well known, however, are the reasons behind the non-compliance behaviours. This chapter seeks to explore the reasons behind the non-compliance behaviours by use of compliance assessment model (CAM). The chapter reviews a case study in a health centre and systematically assesses the reasons behind the non-compliance behaviour by using the CAM model.

scholarly journals Sensitivity of Simulated Deep Convection to a Stochastic Ice Microphysics Framework

2019 ◽  
Vol 11 (11) ◽  
pp. 3362-3389 ◽  
Author(s):  
McKenna W. Stanford ◽  
Hugh Morrison ◽  
Adam Varble ◽  
Judith Berner ◽  
Wei Wu ◽  
...  
Keyword(s):  
Deep Convection ◽  
Ice Microphysics
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