We use geometrical optics and the caustic-touching theorem to study, in an exact way, the change in the topology of the image of an object obtained by reflections on an arbitrary smooth surface. Since the procedure that we use to compute the image is exactly the same as that used to simulate the ideal patterns, referred to as Ronchigrams, in the Ronchi test used to test mirrors, we remark that the closed loop fringes commonly observed in the Ronchigrams when the grating, referred to as a Ronchi ruling, is located at the caustic place are due to a disruption of fringes, or, more correctly, as disruption of shadows corresponding to the ruling bands. To illustrate our results, we assume that the reflecting surface is a spherical mirror and we consider two kinds of objects: circles and line segments.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/ao.47.005500 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
A Soft Robotic Sleeve for Physiotherapy: Improving Elbow Rehabilitation in Baseball Pitchers.
Physiother Res Int
January 2025
Department of Biomedical Engineering, University of Engineering and Technology (UET) Lahore, Narowal Campus, Narowal, Pakistan.
Background And Purpose: Throwing a baseball involves intense exposure of the arm to high speeds and powerful forces, which contributes to an increasing prevalence of arm injuries among athletes. Traditional rigid exoskeletons and rehabilitation equipment frequently lack portability, safety, ergonomic design, and affordability. Traditional rehabilitation approaches frequently require therapist monitoring, resulting in therapy delays.
View Article and Find Full Text PDFAβ40 Fibril Assembly on Human Cerebral Smooth Muscle Cells Impairs Cell Viability.
Biochemistry
January 2025
George and Anne Ryan Institute for Neuroscience, Department of Biomedical and Pharmacological Sciences, University of Rhode Island, Kingston, Rhode Island 02881, United States.
Cerebral vascular deposition of the amyloid-β (Aβ) peptide, a condition known as cerebral amyloid angiopathy (CAA), is associated with intracerebral hemorrhaging and contributes to disease progression in Alzheimer's disease (AD) and vascular cognitive impairment and dementia (VCID). Familial mutations at positions 22 and 23 within the Aβ peptide lead to early onset and severe CAA pathology. Here, we evaluate the effects of fibrillar Aβ peptides on the viability of primary-cultured human cerebral smooth muscle (HCSM) cells, which are the major site of amyloid deposition in cerebral blood vessel walls.
View Article and Find Full Text PDFCoating Agents for Resin Composites: Effect on Color Stability, Roughness, and Surface Micromorphology Subjected to Brushing Wear.
Oper Dent
January 2025
*Roberta Tarkany Basting, DDS, MSc, PhD, Professor, Restorative Dentistry Department, Faculdade São Leopoldo Mandic, São Paulo, Brazil.
This study evaluated the influence of six resin composite coating agents on color stability and surface roughness after toothbrushing abrasion. Discs (Ø6 mm x 2 mm) of nanofilled resin composite (Filtek Z350XT) were prepared for application of coating agents (n=10): control (absence), two surface sealants (PermaSeal and BisCover LV), two adhesive systems (Scotchbond Multi-Purpose Adhesive/3M Oral Care and Single Bond Universal), and two modeling liquids (Modeling Resin and Composite Wetting Resin). CIELab*, WID, and color change (ΔEab, ΔE00, and ΔWID) were analyzed at baseline, after finishing and polishing, after application of coating agents, after coffee staining (simulating 30 days and one year of staining), and after toothbrushing abrasion.
View Article and Find Full Text PDFBioinspired surface structures for added shear stabilization in suction discs.
Sci Rep
January 2025
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA.
Many aquatic organisms utilize suction-based organs to adhere to diverse substrates in unpredictable environments. For multiple fish species, these adhesive discs include a softer disc margin consisting of surface structures called papillae, which stabilize and seal on variable substrates. The size, arrangement, and density of these papillae are quite diverse among different species, generating complex disc patterns produced by these structures.
View Article and Find Full Text PDFTuning the properties of soy protein isolate-based adhesive using various sustainable additives.
Int J Biol Macromol
January 2025
Department of Chemical, Metallurgical and Materials Engineering (Polymer Division), Institute of NanoEngineering Research (INER), Tshwane University of Technology, Pretoria, South Africa.
This work investigates the adhesive property of Soy Protein Isolate(SPI)polymer solution by studying mechanical properties of composites formed using waste wood granules and SPI solutions. To improve the adhesive strength of SPI solution, Carboxymethyl Cellulose Sodium(NaCMC)was mixed (in the weight ratios of 9:1 and 8:2) due to its strong gel formation capabilities. The adhesive performance of these composites was further investigated in the presence and absence of non-toxic additives, including sorbitol (SOR) and stearic acid (SA).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!