Evaluation of Planar Harmonic Impedance for Periodic Elastic Strips of Rectangular Cross Section by Plate Mode Expansion

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Eugene J. Danicki
Keyword(s):  
Rectangular Cross Section ◽  
Perfect Agreement ◽  
Mode Expansion ◽  
Mechanical Field ◽  
Complex Modes ◽  
Matrix Relation ◽  
Bottom Side ◽  
Waves Propagation ◽  
Acoustic Wave Devices ◽  
Energy Conservation Law

A system of periodic elastic strips (each one considered as a piece of a plate) is characterized by a matrix relation between the Bloch series of displacement and traction at the bottom side of the system. Both these mechanical fields are involved in the boundary conditions at the contact plane between the strips and the substrate supporting a Rayleigh wave. The analysis exploits the mechanical field expansion over the plate modes, including complex modes; numerical results satisfy the energy conservation law satisfactorily. The derived planar harmonic Green’s function provides an alternative tool for investigation of surface waves propagation under periodic elastic strips, with respect to pure numerical methods mostly applied in the surface acoustic wave devices literature. Perfect agreement of the presented theory with the experimentally verified perturbation model of thin strips is demonstrated.

Elastic bending wave on the edge of a semi-infinite plate reinforced by a strip plate

2019 ◽  
Vol 24 (10) ◽  
pp. 3319-3330 ◽  
Author(s):  
Ahmed SM Alzaidi ◽  
Julius Kaplunov ◽  
Ludmila Prikazchikova
Keyword(s):  
Dispersion Relation ◽  
Elastic Waves ◽  
Rectangular Cross Section ◽  
Infinite Plate ◽  
Numerical Data ◽  
Free Edge ◽  
Matrix Relation ◽  
Strip Plate ◽  
Effective Conditions ◽  
Bending Wave

Elastic waves localised near the edge of a semi-infinite plate reinforced by a strip plate are considered within the framework of the 2D classical theory for plate bending. The boundary value problem for the strip plate is subject to asymptotic analysis, assuming that a typical wavelength is much greater than the strip thickness. As a result, effective conditions along the interface corresponding to a plate reinforced by a beam with a narrow rectangular cross-section are established. They support an approximate dispersion relation perturbing that for a homogeneous plate with a free edge. The accuracy of the approximate dispersion relation is tested by comparison with the numerical data obtained from the ‘exact’ matrix relation for a composite plate. The effect of the problem parameters on the localisation rate is studied.

Surface Structure in Microtomed Sections Caused by Glass and Diamond Knives

1971 ◽  
Vol 29 ◽  
pp. 456-457
Author(s):  
J. Temple Black ◽  
William G. Boldosser
Keyword(s):  
Plastic Deformation ◽  
Epoxy Resin ◽  
Carbon Coating ◽  
Surface Damage ◽  
Body Angle ◽  
Normal Manner ◽  
Bottom Side ◽  
Cutting Direction ◽  
Made In ◽  
Diamond Knife

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.

Mode expansion and photon operators in dispersive and absorbing dielectrics

2001 ◽  
Vol 48 (1) ◽  
pp. 67-84 ◽  
Author(s):  
Omar Di Stefano ◽  
Salvatore Savasta ◽  
Raffaello Girlanda
Keyword(s):  
Mode Expansion

Media Psychology and Complex Modes of Entertainment Experiences

2011 ◽  
Vol 23 (1) ◽  
pp. 34-38 ◽  
Author(s):  
Christoph Klimmt
Keyword(s):  
Empirical Studies ◽  
Terror Management Theory ◽  
Death And Dying ◽  
Terror Management ◽  
Media Psychology ◽  
Mixed Emotions ◽  
Theoretical Perspectives ◽  
Complex Modes ◽  
History Of ◽  
Media Enjoyment

This comment briefly examines the history of entertainment research in media psychology and welcomes the conceptual innovations in the contribution by Oliver and Bartsch (this issue). Theoretical perspectives for improving and expanding the “appreciation” concept in entertainment psychology are outlined. These refer to more systematic links of appreciation to the psychology of mixed emotions, to positive psychology, and to the psychology of death and dying – in particular, to terror management theory. In addition, methodological challenges are discussed that entertainment research faces when appreciation and the experience of “meaning for life” need to be addressed in empirical studies of media enjoyment.

Validity of puberty self-report in children and adolescents in Ho Chi Minh City

MedPharmRes ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 33-37
Author(s):  
Tam M. Do ◽  
Thanh K. Van ◽  
Huyen TT. Bich ◽  
Thanh TK. Tran ◽  
Minh X. Ngo ◽  
...  
Keyword(s):  
Children And Adolescents ◽  
Sexual Maturation ◽  
Kappa Statistic ◽  
Community Context ◽  
Self Report ◽  
Ho Chi Minh City ◽  
Pubertal Stage ◽  
Perfect Agreement ◽  
Kendall’S Τ ◽  
High Concordance

Background: Puberty is a milestone in child and adolescent development, yet a feasible tool to accurately assess pubertal stage in community context has not been validated in Vietnam. Aim: This study was conducted to validate pubertal self-report among Ho Chi Minh City children and adolescents in comparison with paediatrician’s assessment. Methods: 80 girls and 76 boys aged from 6 to 17 years old from 5 schools in Ho Chi Minh City were recruited. Self-administered questionnaires about sexual maturation were distributed to participants and results were compared with physician’s pubertal examination. Kappa statistic and Kendall’s τ b were used to evaluate validity of the questionnaire. Results: Boys tended to overestimate their development stages while girls tended to underestimate. Fair to almost perfect agreement between students’ reports and paediatricians’ evaluation, along with high concordance was recorded, however younger boys (aged 6-11) showed limited evaluation of their own sexual maturation. Conclusion: This method was inaccurate to evaluate younger boys’ sexual maturation; however, acceptable accuracy in sexual maturation estimation among younger girls and adolescents could allow it to serve as an effective screening tool in community context.

A novel method for the determination of linting propensity of paper

TAPPI Journal ◽  
2012 ◽  
Vol 11 (10) ◽  
pp. 9-17
Author(s):  
ALESSANDRA GERLI ◽  
LEENDERT C. EIGENBROOD
Keyword(s):  
Ash Content ◽  
The Novel ◽  
Offset Printing ◽  
Excellent Correlation ◽  
End Conditions ◽  
Bottom Side ◽  
Novel Method ◽  
Total Fraction

A novel method was developed for the determination of linting propensity of paper based on printing with an IGT printability tester and image analysis of the printed strips. On average, the total fraction of the surface removed as lint during printing is 0.01%-0.1%. This value is lower than those reported in most laboratory printing tests, and more representative of commercial offset printing applications. Newsprint paper produced on a roll/blade former machine was evaluated for linting propensity using the novel method and also printed on a commercial coldset offset press. Laboratory and commercial printing results matched well, showing that linting was higher for the bottom side of paper than for the top side, and that linting could be reduced on both sides by application of a dry-strength additive. In a second case study, varying wet-end conditions were used on a hybrid former machine to produce four paper reels, with the goal of matching the low linting propensity of the paper produced on a machine with gap former configuration. We found that the retention program, by improving fiber fines retention, substantially reduced the linting propensity of the paper produced on the hybrid former machine. The papers were also printed on a commercial coldset offset press. An excellent correlation was found between the total lint area removed from the bottom side of the paper samples during laboratory printing and lint collected on halftone areas of the first upper printing unit after 45000 copies. Finally, the method was applied to determine the linting propensity of highly filled supercalendered paper produced on a hybrid former machine. In this case, the linting propensity of the bottom side of paper correlated with its ash content.

Efficiency of open cast peat mining with mechanical field dewatering

2019 ◽  
Vol 7 ◽  
pp. 30-41
Author(s):  
A.V. Mikhailov ◽  
◽  
O.J. Garmaev ◽  
A.S. Fedorov ◽  
D.R. Garifullin ◽  
...  
Keyword(s):  
Peat Mining ◽  
Mechanical Field ◽  
Open Cast
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