We consider the limit of geometric concentration for a focusing concave mirror, e.g., a parabolic trough or dish, designed to collect all radiation within a finite acceptance angle and direct it to a receiver with a flat or circular cross-section. While a concentrator with a parabolic cross-section indeed achieves this limit, it is not the only geometry capable of doing so. We demonstrate that there are infinitely many solutions. The significance of this finding is that geometries which can be more easily constructed than the parabola can be utilized without loss of concentration, thus presenting new avenues for reducing the cost of solar collectors. In particular, we investigate a low-cost trough mirror profile which can be constructed by inflating a stack of thin polymer membranes and show how it can always be designed to match the geometric concentration of a parabola of similar form.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/OL.39.004301 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
This analysis assessed the relationship between the plasma concentrations of loperamide and its N-desmethyl loperamide meta- bolite (M1) and the potential QT interval prolongation at therapeutic and supratherapeutic doses. The exposure-response analysis was performed using the data from healthy adults participating in a randomized, double-blind, single-dose, four-way (placebo; loperamide 8 mg [therapeutic]; loperamide 48 mg [supratherapeutic]; moxifloxacin 400 mg [positive control]) crossover study. The electrocardiographic measurements extracted from 12-lead digital Holter recordings were time-matched to pharmacokinetic sampling of loperamide/M1.
View Article and Find Full Text PDFSerotype-specific serum immunoglobulin G at 18 months of age following one or two doses of a primary series of 10-valent or 13-valent pneumococcal conjugate vaccine and a booster dose at nine months of age: a randomized controlled study.
Expert Rev Vaccines
December 2025
South Africa Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, University of the Witwatersrand, Faculty of Health Science, Johannesburg, South Africa.
Background: Due to high costs of pneumococcal conjugate vaccines (PCV), transitioning from a two (2 + 1) to a single dose (1 + 1) primary series with a booster should be considered. This study evaluated the immune response at 18 months of age following a 1 + 1 compared to a 2 + 1 schedule of 10-valent (PCV10) and 13-valent (PCV13) vaccines.
Research Design And Methods: A single-center, open-label, randomized trial conducted in Soweto, South Africa, evaluated the immunogenicity of differing dosing schedule for PCV10 and PCV13.
Effect of Staggered vs. Simultaneous Co-Administration of Bempedoic Acid on Pharmacokinetics of Pravastatin: Randomized, Cross-Over Clinical Trial in Healthy Volunteers.
Pharmaceutics
January 2025
Medical Faculty Heidelberg, Heidelberg University, 69117 Heidelberg, Germany.
: Bempedoic acid (BA) is a novel cholesterol-lowering agent with proven positive effects on cardiovascular endpoints. Because it is an inhibitor of the hepatic transporters OATP1B1 and OATP1B3, two uptake transporters regulating the intrahepatic availability of statins, it increases the systemic exposure of co-administered statins. This interaction could raise the risk of myopathy.
View Article and Find Full Text PDFGeometry-Based Synchrosqueezing S-Transform with Shifted Instantaneous Frequency Estimator Applied to Gearbox Fault Diagnosis.
Sensors (Basel)
January 2025
Heime (Tianjin) Electrical Engineering Systems Co., Ltd., Tianjin 301700, China.
This paper introduces a novel geometry-based synchrosqueezing S-transform (GSSST) for advanced gearbox fault diagnosis, designed to enhance diagnostic precision in both planetary and parallel gearboxes. Traditional time-frequency analysis (TFA) methods, such as the Synchrosqueezing S-transform (SSST), often face challenges in accurately representing fault-related features when significant mode closely spaced components are present. The proposed GSSST method overcomes these limitations by implementing an intuitive geometric reassignment framework, which reassigns time-frequency (TF) coefficients to maximize energy concentration, thereby allowing fault components to be distinctly isolated even under challenging conditions.
View Article and Find Full Text PDFDerivation of human toxicokinetic parameters and internal threshold of toxicological concern for tenuazonic acid through a human intervention trial and hierarchical Bayesian population modeling.
J Expo Sci Environ Epidemiol
January 2025
Centre of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium.
Background: Tenuazonic acid (TeA), a mycotoxin produced by Alternaria alternata, contaminates various food commodities and is known to cause acute and chronic health effects. However, the lack of human toxicokinetic (TK) data and the reliance on external exposure estimates have stalled a comprehensive risk assessment for TeA.
Objective: To bridge this gap, a human TK trial and population-based TK (PopTK) modeling were applied to determine human TK parameters of TeA, and the results were applied for risk screening using population biomonitoring data and threshold of toxicological concern (TTC)-based approaches.
Want 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!