On an elastodynamic classification of orthorhombic media

1981 ◽  
Vol 374 (1758) ◽  
pp. 401-429 ◽  
Keyword(s):  
Plane Wave ◽  
Classification Scheme ◽  
Wave Theory ◽  
Coordinate Plane ◽  
Spruce Wood ◽  
Bulk Waves ◽  
Homogeneous Plane ◽  
Wave Surfaces ◽  
Orthorhombic Materials

Sets of elastic constants for crystalline media are normally presented with reference to the axes of the unit cell defined by structural crystallographers (Landolt & Bdrnstein 1979). In orthorhombic materials, the magnitudes of the nine elastic stiffnesses, in general, show little or no consistent correspondence with the suffixes (related to crystal axes) of the physical constants. A classification scheme for orthorhombic media, based on an ordering of the elastodynamically important principal stiffnesses of extension ( c 11 , c 22 , c 33 ) and of shear ( c 44 , c 55 , c 66 ), is described and illustrated. The classification facilitates meaningful comparisons of elastodynamic properties since it offers the following advantages: (i) It is amenable to cyclic interchange. (ii) It permits concise expression of basic homogeneous plane wave theory (Musgrave 1970). (iii) It affords rapid appreciation of the possible essential configurations of homogeneous plane wave slowness in each coordinate plane. (iv) It allows known criteria for the existence of hyperbolic regions in elastic slowness and wave surfaces (Musgrave 1957,1979) and some further developments, to be succinctly expressed. Application of the scheme to the theory of bulk waves is exemplified in detail for three media, diverse in their properties, a-uranium, spruce (wood) and a hypothetical medium discussed by Al’shits & Lothe (19796); specification of exceptional, limiting bulk waves (Chadwick & Smith 1977) is included.

Geometric Characteristics of the Center-Point Curve Based on the Kinematics of the Compatibility Linkage

1992 ◽  
Author(s):  
J. A. Schaaf ◽  
J. A. Lammers
Keyword(s):  
Complex Number ◽  
Change Point ◽  
Double Point ◽  
Classification Scheme ◽  
Center Point ◽  
Degenerate Form ◽  
Point Curve ◽  
Position Synthesis ◽  
Point Form

Abstract In this paper we develop a method of characterizing the center-point curves for planar four-position synthesis. We predict the five characteristic shapes of the center-point curve using the kinematic classification of the compatibility linkage obtained from a complex number formulation for planar four-position synthesis. This classification scheme is more extensive than the conventional Grashof and non-Grashof classifications in that the separate classes of change point compatibility linkages are also included. A non-Grashof compatibility linkage generates a unicursal form of the center-point curve; a Grashof compatibility linkage generates a bicursal form; a single change point compatibility linkage generates a double point form; and a double or triple change point compatibility linkage generates a circular-degenerate or a hyperbolic-degenerate form.

Atherosis of trophoblast type: A specific form of decidual vasculopathy distinct from atherosis of macrophage type

2021 ◽  
Author(s):  
Peilin Zhang
Keyword(s):  
Mixed Type ◽  
Classification Scheme ◽  
Late Pregnancy ◽  
Placental Weight ◽  
Placental Pathology ◽  
New Classification ◽  
Vascular Abnormalities ◽  
Medial Necrosis ◽  
Acute Atherosis

Background: There are three types of decidual vasculopathy, namely, acute atherosis, fibrinoid medial necrosis and mural arterial hyerptrophy. Persistence of vascular trophoblasts is also known to be related to maternal vascular malperfusion, but detailed study is lacking. Material and methods: A total 1017 placentas from 2021 were collected with clinical, neonatal and placental information, and routine placental pathology examination was performed. Decidual vasculopathy was classified based on the new classification scheme including atherosis of macrophage type atherosis of trophoblast type, fibrinoid medial necrosis, mural arterial hypertrophy and mixed type vasculopathy. The significance of these morphologic changes were examined based on the clinical, neonatal and placental pathology features. Results: Decidual vasculopathy is classified as classic type, mural hypertrophy and mixed type. Classic type vasculopathy is further separated as atherosis and fibrinoid medial necrosis. Atherosis is defined as atherosis of macrophage type and atherosis of trophoblast type. Each category of decidual vasculopathy was evaluated in association with maternal, neonatal and placental pathologic findings. Atherosis of macrophage type and mixed type vasculopathy showed statistically significant association with preeclampsia/pregnancy induced hypertension, low birth weight and low placental weight. Atherosis of trophoblast type was associated with lower placental weight but not with specific clinical features. There is no neonatal sex dimorphism in decidual vasculopathy. Conclusion: Atherosis of trophoblast type is a distinct pathologic feature in late pregnancy, and it is associated with lower placental weight. New classification of decidual vasculopathy helps with better stratification and categorization of placental maternal vascular abnormalities.

scholarly journals ACCURACY ASSESSMENTS OF PAN-SHARPENED IMAGE FOR BENTHIC HABITATS MAPPING

2017 ◽  
Vol 4 (1) ◽  
pp. 27 ◽  
Author(s):  
Pramaditya Wicaksono ◽  
Faza Adhimah
Keyword(s):  
Spatial Resolution ◽  
Classification Scheme ◽  
Spectral Response ◽  
Hierarchical Classification ◽  
Visual Interpretation ◽  
Benthic Habitats ◽  
Visual Appearance ◽  
Accuracy Assessments

Image-sharpening process integrates lower spatial resolution multispectral bands with higher spatial resolution panchromatic band to produce multispectral bands with finer spatial detail called pan-sharpened image. Although the pan-sharpened image can greatly assist the process of information extraction using visual interpretation, the benefit and setback of using pan-sharpened image on the accuracy of digital classification for mapping remain unclear. This research aimed at 1) highlighting the issue of using pan-sharpened image to perform benthic habitats mapping and 2) comparing the accuracy of benthic habitats mapping using original and pan-sharpened bands. In this study, Quickbird image was used and Kemujan Island was selected as the study area. Two levels of hierarchical classification scheme of benthic habitats were constructed based on the composition of in situ benthic habitats. PC Spectral sharpening method was applied on Quickbird image. Image radiometric corrections, PCA transformation, and image classifications were performed on both original and pan-sharpened image. The results showed that the accuracy of benthic habitats classification of pan-sharpened image (maximum overall accuracy 64.28% and 73.30% for per-pixel and OBIA, respectively) was lower than the original image (73.46% and 73.10%, respectively). The main setback of using pan-sharpened image is the inability to correct the sunglint, hence adversely affects the process of water column correction, PCA transformation and image classification. This is mainly because sunglint do not only affect object’s spectral response but also the texture of the object. Nevertheless, the pan-sharpened image can still be used to map benthic habitats using visual interpretation and digital image processing. Pan-sharpened image will deliver better classification accuracy and visual appearance especially when the sunglint is low.

scholarly journals The Banff Working Group Classification of Definitive Polyomavirus Nephropathy: Morphologic Definitions and Clinical Correlations

2017 ◽  
Vol 29 (2) ◽  
pp. 680-693 ◽  
Author(s):  
Volker Nickeleit ◽  
Harsharan K. Singh ◽  
Parmjeet Randhawa ◽  
Cinthia B. Drachenberg ◽  
Ramneesh Bhatnagar ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Working Group ◽  
Classification Scheme ◽  
Clinical Presentation ◽  
Interstitial Fibrosis ◽  
The United States ◽  
Systematic Analysis ◽  
Definition Of ◽  
Morphologic Classification

Polyomavirus nephropathy (PVN) is a common viral infection of renal allografts, with biopsy-proven incidence of approximately 5%. A generally accepted morphologic classification of definitive PVN that groups histologic changes, reflects clinical presentation, and facilitates comparative outcome analyses is lacking. Here, we report a morphologic classification scheme for definitive PVN from the Banff Working Group on Polyomavirus Nephropathy, comprising nine transplant centers in the United States and Europe. This study represents the largest systematic analysis of definitive PVN undertaken thus far. In a retrospective fashion, clinical data were collected from 192 patients and correlated with morphologic findings from index biopsies at the time of initial PVN diagnosis. Histologic features were centrally scored according to Banff guidelines, including additional semiquantitative histologic assessment of intrarenal polyomavirus replication/load levels. In-depth statistical analyses, including mixed effects repeated measures models and logistic regression, revealed two independent histologic variables to be most significantly associated with clinical presentation: intrarenal polyomavirus load levels and Banff interstitial fibrosis ci scores. These two statistically determined histologic variables formed the basis for the definition of three PVN classes that correlated strongest with three clinical parameters: presentation at time of index biopsy, serum creatinine levels/renal function over 24 months of follow-up, and graft failure. The PVN classes 1–3 as described here can easily be recognized in routine renal biopsy specimens. We recommend using this morphologic PVN classification scheme for diagnostic communication, especially at the time of index diagnosis, and in scientific studies to improve comparative data analysis.

Dip selective 2-D multiple attenuation in the plane‐wave domain

Geophysics ◽  
2000 ◽  
Vol 65 (1) ◽  
pp. 264-274 ◽  
Author(s):  
Faqi Liu ◽  
Mrinal K. Sen ◽  
Paul L. Stoffa
Keyword(s):  
Plane Wave ◽  
Source Function ◽  
Real Data ◽  
Wave Theory ◽  
Geological Structure ◽  
Multiple Attenuation ◽  
Invariant Embedding ◽  
Free Data ◽  
Air Water Interface ◽  
Lateral Variations

In many geological settings, strong reflections at the air‐water interface contribute to most of the multiple energy in the recorded seismograms. Here, we describe a method for free‐surface multiple attenuation using a reflection operator model of a seismic record, derived using the well‐known invariant embedding technique. We implement this method in the 2-D plane‐wave domain, where lateral variation of the geological structure of the earth is taken into account by the coupling of different ray parameters. In situations where the lateral variations are smooth, the data are well compressed in the 2-D plane‐wave domain and the resultant bandlimited matrices significantly reduce the computation cost. One important feature of the proposed method is its flexibility, which allows for the removal of multiples from selected reflections. To generate multiple free data, wave‐theory‐based multiple attenuation methods attempt to estimate either the source function or the subsurface reflectivity. Our method takes advantage of both approaches, such that we initially predict multiple traveltime using the reflectivity approach and then seek a source function to predict the amplitudes. Synthetic and real data examples show that this method is stable and successful in attenuating the surface multiples.

Ultrasonographic prevalence and proposed morphologic classification of bilobed gallbladder in cats

2021 ◽  
pp. 1098612X2110556
Author(s):  
Heather N Spain ◽  
Dominique G Penninck ◽  
Michael Thelen
Keyword(s):  
Classification Scheme ◽  
Ultrasound Examination ◽  
Abdominal Ultrasound ◽  
Complete Evaluation ◽  
Ultrasound Evaluation ◽  
Plane Image ◽  
Morphologic Type ◽  
The Relationship ◽  
Abdominal Ultrasound Examination

Objectives Morphologic anomalies of the feline gallbladder (GB) have been previously reported in the literature. These morphologic variants are frequently encountered on routine abdominal ultrasound examination. The aim of this study was to provide an ultrasonographic classification system of these variants and document the overall incidence in the feline population. Methods A prospective, descriptive study was undertaken; cats that had an abdominal ultrasound examination that included at least one sagittal and transverse plane image of the GB were included. GB shape was evaluated and categorized based on a classification scheme of morphologic variants modified from the human literature. Septated (S), bilobed (B1, B2, B3), duplex (D) and complex (C) categories were described. Results Of 516 cats included in the study, 389 had normal GB morphology, while 127 had anomalous GB morphology. The overall incidence rate of anomalous GB morphology was 24.61%. When examined by morphologic type, the septated (S) morphology had an incidence of 9.69%. A bilobed (B) morphology was the most commonly observed classification; incidence was 14.35% within our population; incidence of B1, B2 and B3 subtypes were 2.91%, 6.98% and 4.46%, respectively. Duplex GBs only made up 0.39% of the total population. The incidence of complex (C) morphologies was 0.19%. Conclusions and relevance The incidence of GB morphologic anomalies was higher in our population than previously reported. Identification of these anomalies on routine ultrasound evaluation is common; numerous different morphologies can be identified and a standardized classification scheme is proposed. Complete evaluation of morphology can be challenging, particularly with regard to cystic duct anatomy. Clinical significance is uncertain and future studies are warranted to determine the relationship between morphologic variants and hepatobiliary disease.

Sign in / Sign up

Export Citation Format

Share Document