Geometry of Structures Developed by Anisotropic Etching in the Nanometer Range

2021 ◽  
Vol 23 (3) ◽  
pp. 131-138
Author(s):  
Yu.V. Larionov ◽  
Keyword(s):  
Anisotropic Etching ◽  
Linear Measurements ◽  
Nanometer Range ◽  
Nanostructure Surface ◽  
Sidewall Surface

Geometric disadvantages of nanostructure surface developed by anisotropic etching of silicon are discussed. These disadvantages increase uncertainness of its sizes and impeded its using as an etalons for linear measurements. The greatest uncertainness are observed for structures with trapezoid profile. They make up due to defects on sidewalls of etched structures. The surface of a sidewall is proposed to be disposed in the [111] plane and so be absolutely flat. Really parts of a sidewall surface are deflected in stepwise way from the plane [111]. This phenomenon leads to deflection of angles between converging flat sections of etched structure from its known values for silicon. Consequence of this is most drastic to a measure MShps-2K due to its structure, technology of anisotropic etching and absence of required control. Sources of these surface disadvantages induced by anisotropic etching are discussed. Possibilities to decrease disadvantages are evaluated.

Etalon for Nanometrology Produced by Anisotropic Etching

2021 ◽  
Vol 23 (4) ◽  
pp. 171-178
Author(s):  
Yu.V. Larionov ◽  
Keyword(s):  
Sample Surface ◽  
Anisotropic Etching ◽  
Geometric Parameters ◽  
National Scale ◽  
Linear Measurements ◽  
Important Condition ◽  
Rectangular Profile ◽  
Measurement Results

Possibilities and results of using relief structures produced by anisotropic etching as etalons for linear measurements in nanorange are discussed. Two types of the structures with different profiles and with two approaches to estimation of influence of its sophistication degree on measurement results are considered. Analyze of methods and means of measurements of its geometric parameters and comparison of uncertainness of measurement results are conducted. The important condition for diminishing the measurements uncertainness is taking into account irregularities of a sample surface. These irregularities were evaluated by TEM and CD-AFM. Results of harnessing these types of structures are different also. The bureau International des Poids et Mesures recommended the structure with rectangular profile and its attestation procedure as an example for all national committees on linewidth metrology in nanorange. The structure with trapezoid profile that induced hopes for decision of basic tasks of nanometrology in past is occurred to be poorly in demand even on national scale.

Modeling drive wheels of hoisting machines with rubber cables

2020 ◽  
pp. 105-114
Author(s):  
V. E. Perekutnev ◽  
V. V. Zotov
Keyword(s):  
Stress State ◽  
Safety Factor ◽  
Numerical Models ◽  
Design Parameters ◽  
Potential Range ◽  
Capital Costs ◽  
Reducing Gear ◽  
Reduce Risk ◽  
Steel Cables ◽  
Sidewall Surface

Upgrading of hoisting machines aims to improve their performance, to reduce risk of accidents, and to cut down operational and capital costs. One of the redesign solutions is replacement of steel cables by rubber cables. This novation can extend life of pulling members, decrease diameters of drive and guide wheels and, consequently, elements of the whole hoisting machines: rotor, reducing gear, motor. This engineering novation needs re-designing of hoisting machines; thus, the new design should be validated, in particular, strength characteristics of the machine members. This article considers a drive wheel of a hoisting machine with a pulling belt. In order to justify the potential range of design parameters with regard to safety factor, the numerical models of different-design drive wheels are developed and their operation with pulling belt (rubber cable) is simulated in the SolidWorks environment. The data on the stress state of the wheel elements are analyzed, the most loaded points are identified, and the maximal stresses on the sidewall surface and in the spokes of wheels of different designs are plotted.

scholarly journals Automatic linear measurements of the fetal brain on MRI with deep neural networks

2021 ◽  
Author(s):  
Netanell Avisdris ◽  
Bossmat Yehuda ◽  
Ori Ben-Zvi ◽  
Daphna Link-Sourani ◽  
Liat Ben-Sira ◽  
...  
Keyword(s):  
Neural Networks ◽  
Deep Neural Networks ◽  
Fetal Brain ◽  
Linear Measurements

scholarly journals Temporomandibular Joint Osseous Morphology of Class I and Class II Malocclusions in the Normal Skeletal Pattern: A Cone-Beam Computed Tomography Study

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 541
Author(s):  
Xiao-Chuan Fan ◽  
Lin-Sha Ma ◽  
Li Chen ◽  
Diwakar Singh ◽  
Xiaohui Rausch-Fan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Temporomandibular Joint ◽  
Cone Beam Computed Tomography ◽  
Class Ii ◽  
Class I ◽  
Cone Beam ◽  
Glenoid Fossa ◽  
Linear Measurements ◽  
Significant Difference ◽  
Skeletal Pattern

(1) Background—The aim of the present study was to evaluate the correlation between the temporomandibular joint (TMJ) osseous morphology of normal skeletal pattern individuals with different dental malocclusions by using cone-beam computed tomography (CBCT). (2) Methods—The CBCT images of bilateral TMJs in 67 subjects with skeletal class I and average mandibular angle (26 males and 41 females, age range 20–49 years) were evaluated in this study. The subjects were divided into class I, class II division 1, and class II division 2 according to the molar relationship and retroclination of the maxillary incisors. Angular and linear measurements of TMJ were evaluated and the differences between the groups were statistically analyzed. (3) Results—Intragroup comparisons showed statistical differences for articular eminence inclination, the width of the glenoid fossa, the ratio of the width of the glenoid fossa to the depth of the glenoid fossa, the condylar angle, and the intercondylar angle between the malocclusion groups. The measurements of the glenoid fossa shape showed no significant difference between the left and right sides. Females showed more differences in the morphological parameters of TMJ between the three malocclusion groups than the males. (4) Conclusion—The present study revealed differences in the TMJ osseous morphology between dental class I and class II malocclusions in the normal skeletal pattern.

scholarly journals Pattern and pace of morphological change due to variable human impact: the case of Japanese macaques

Primates ◽  
2021 ◽  
Author(s):  
Madeleine Geiger
Keyword(s):  
Body Size ◽  
Human Impact ◽  
Morphological Variation ◽  
Japanese Macaques ◽  
Linear Measurements ◽  
Skull Shape ◽  
Rates Of Change ◽  
Animal Populations ◽  
Captive Populations ◽  
In Captivity

AbstractHuman impact influences morphological variation in animals, as documented in many captive and domestic animal populations. However, there are different levels of human impact, and their influence on the pattern and rate of morphological variation remains unclear. This study contributes to the ongoing debate via the examination of cranial and mandibular shape and size variation and pace of change in Japanese macaques (Macaca fuscata). This species is ideal for tackling such questions because different wild, wild-provisioned, and captive populations have been monitored and collected over seven decades. Linear measurements were taken on 70 skulls from five populations, grouped into three ‘human impact groups’ (wild, wild-provisioned, and captive). This made it possible to investigate the pattern and pace of skull form changes among the human impact groups as well as over time within the populations. It was found that the overall skull shape tends to differ among the human impact groups, with captive macaques having relatively longer rostra than wild ones. Whether these differences are a result of geographic variation or variable human impact, related to nutritional supply and mechanical properties of the diet, is unclear. However, this pattern of directed changes did not seem to hold when the single captive populations were examined in detail. Although environmental conditions have probably been similar for the two examined captive populations (same captive locality), skull shape changes over the first generations in captivity were mostly different. This varying pattern, together with a consistent decrease in body size in the captive populations over generations, points to genetic drift playing a role in shaping skull shape and body size in captivity. In the captive groups investigated here, the rates of change were found to be high compared to literature records from settings featuring different degrees of human impact in different species, although they still lie in the range of field studies in a natural context. This adds to the view that human impact might not necessarily lead to particularly fast rates of change.

scholarly journals Geometric morphometric investigation of craniofacial morphological change in domesticated silver foxes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Timothy M. Kistner ◽  
Katherine D. Zink ◽  
Steven Worthington ◽  
Daniel E. Lieberman
Keyword(s):  
Three Dimensional ◽  
Cranial Base ◽  
Craniofacial Morphology ◽  
Wild Populations ◽  
Linear Measurements ◽  
Skeletal Morphology ◽  
Geometric Morphometric ◽  
Domestication Syndrome ◽  
Morphometric Investigation ◽  
Unselected Population

AbstractTo test the effects of domestication on craniofacial skeletal morphology, we used three-dimensional geometric morphometrics (GM) along with linear and endocranial measurements to compare selected (domesticated) and unselected foxes from the Russian Farm-Fox Experiment to wild foxes from the progenitor population from which the farmed foxes are derived. Contrary to previous findings, we find that domesticated and unselected foxes show minimal differences in craniofacial shape and size compared to the more substantial differences between the wild foxes and both populations of farmed foxes. GM analyses and linear measurements demonstrate that wild foxes differ from farmed foxes largely in terms of less cranial base flexion, relatively expanded cranial vaults, and increased endocranial volumes. These results challenge the assumption that the unselected population of foxes kept as part of the Russian Farm-Fox experiment are an appropriate proxy for ‘wild’ foxes in terms of craniofacial morphology and highlight the need to include wild populations in further studies of domestication syndrome to disentangle the phenotypic effects of multiple selection pressures. These findings also suggest that marked increases in docility cannot be reliably diagnosed from shape differences in craniofacial skeletal morphology.

scholarly journals Estimating Craniofacial Growth Cessation: Comparison of Asymptote- and Rate-Based Methods

2021 ◽  
pp. 105566562110026
Author(s):  
Anna M. Hardin ◽  
Ryan P. Knigge ◽  
Hee Soo Oh ◽  
Manish Valiathan ◽  
Dana L. Duren ◽  
...  
Keyword(s):  
Estimation Method ◽  
Logistic Models ◽  
Careful Consideration ◽  
Craniofacial Growth ◽  
Craniofacial Anomalies ◽  
Linear Measurements ◽  
Growth Cessation ◽  
Lateral Cephalograms ◽  
Males And Females ◽  
Important Milestone

Objective: To identify differences between asymptote- and rate-based methods for estimating age and size at growth cessation in linear craniofacial measurements. Design: This is a retrospective, longitudinal study. Five linear measurements were collected from lateral cephalograms as part of the Craniofacial Growth Consortium Study (CGCS). Four estimates of growth cessation, including 2 asymptote- (GCasym, GCerr) and 2 rate-based (GCabs, GC10%) methods, from double logistic models of craniofacial growth were compared. Participants: Cephalometric data from participants in 6 historic longitudinal growth studies were included in the CGCS. At least 1749 individuals (870 females, 879 males), unaffected by craniofacial anomalies, were included in all analyses. Individuals were represented by a median of 11 images between 2.5 and 31.3 years of age. Results: GCasym consistently occurred before GCerr and GCabs consistently occurred before GC10% within the rate-based approaches. The ordering of the asymptote-based methods compared to the rate-based methods was not consistent across measurements or between males and females. Across the 5 measurements, age at growth cessation ranged from 13.56 (females, nasion-basion, GCasym) to 24.39 (males, sella-gonion, GCerr). Conclusions: Adolescent growth cessation is an important milestone for treatment planning. Based on our findings, we recommend careful consideration of specific definitions of growth cessation in both clinical and research settings since the most appropriate estimation method may differ according to patients’ needs. The different methods presented here provide useful estimates of growth cessation that can be applied to raw data and to a variety of statistical models of craniofacial growth.

scholarly journals Assessment of necessity of neuronavigation in localization of calvarial extra-axial lesions in the setting of limited resources

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hussein Soffar ◽  
Mohamed F. Alsawy
Keyword(s):  
Conventional Method ◽  
Linear Measurement ◽  
Limited Resources ◽  
Linear Measurements ◽  
Surgical Interventions ◽  
Localization Method ◽  
Mean Error ◽  
Significant Difference ◽  
The Mean ◽  
Mean Time

Abstract Background Neuronavigation is a very beneficial tool in modern neurosurgical practice. However, the neuronavigation is not available in most of the hospitals in our country raising the question about its importance in localizing the calvarial extra-axial lesions and to what extent it is safe to operate without it. Methods We studied twenty patients with calvarial extra-axial lesions who underwent surgical interventions. All lesions were preoperatively located with both neuronavigation and the usual linear measurements. Both methods were compared regarding the time consumed to localize the tumor and the accuracy of each method to anticipate the actual center of the tumor. Results The mean error of distance between the planned center of the tumor and the actual was 6.50 ± 1.762 mm in conventional method, whereas the error was 3.85 ± 1.309 mm in IGS method. Much more time was consumed during the neuronavigation method including booting, registration, and positioning. A statistically significant difference was found between the mean time passed in the conventional method and IGS method (2.05 ± 0.826, 24.90 ± 1.334, respectively), P-value < 0.001. Conclusion In the setting of limited resources, the linear measurement localization method seems to have an accepted accuracy in the localization of calvarial extra-axial lesions and it saves more time than neuronavigation method.

scholarly journals Modelling growth curves of the normal infant’s mandible: 3D measurements using computed tomography

2021 ◽  
Author(s):  
Jan Aart M. Schipper ◽  
Manouk J. S. van Lieshout ◽  
Stefan Böhringer ◽  
Bonnie L. Padwa ◽  
Simon G. F. Robben ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Growth Models ◽  
Normal Growth ◽  
Growth Patterns ◽  
Ct Scans ◽  
Mandibular Ramus ◽  
Linear Measurements ◽  
Mandibular Growth ◽  
Gonial Angle ◽  
Mandibular Body

Abstract Objectives Data on normal mandibular development in the infant is lacking though essential to understand normal growth patterns and to discriminate abnormal growth. The aim of this study was to provide normal linear measurements of the mandible using computed tomography performed in infants from 0 to 2 years of age. Material and methods 3D voxel software was used to calculate mandibular body length, mandibular ramus length, bicondylar width, bigonial width and the gonial angle. Intra- and inter-rater reliability was assessed for these measurements. They were found to be sufficient for all distances; intra-class correlation coefficients were all above 0.9. Regression analysis for growth modelling was performed. Results In this multi-centre retrospective study, 109 CT scans were found eligible that were performed for various reasons (e.g. trauma, craniosynostosis, craniofacial abscesses). Craniosynostosis patients had larger mandibular measurements compared to non-craniosynostosis patients and were therefore excluded. Fifty-one CT scans were analysed. Conclusions Analysis showed that the mandible increases more in size vertically (the mandibular ramus) than horizontally (the mandibular body). Most of the mandibular growth occurs in the first 6 months. Clinical relevance These growth models provide insight into normal mandibular development in the first 2 years of life. This reference data facilitates discrimination between normal and abnormal mandibular growth.

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