Search

Purpose: Before radiology and arthroscopy, an arthrotomy had to be made for a definitive diagnosis and treat intraarticular pathology. Before arthroscopy, endoscopy was performed on other organs, and particularly the bladder. This paper aimed to investigate the transition of the cystoscope to the arthroscope, and all the bright innovations about light and optics that finally allow arthroscopy. Methods: Physicians have always wanted to examine their patients' body cavities. Some cavities are quite accessible for diagnostic purposes, using specula and light, while others are difficult to inspect. The female bladder was the first organ to be examined using an endoscope with some light by Philipp Bozzini in 1806. We report the important innovations and inventions done by surgeons but also by scientists in optic and electricity during two centuries before arriving to arthroscopy. Results: Whereas the urologists immediately embraced the idea of endoscopy, and adapted the rules of optic and the progress in electricity to allow bladder illumination and examination with cystoscopes, the orthopedic surgeons were reluctant. We focus on the early history of endoscopy and arthroscopy specifically. Our story ends in 1918 with Dr. Severin Nordentoft in Germany and Professor Kenji Takagi in Japan began with cystoscopes before designing the first arthroscopes for performing the first knee arthroscopies. Conclusion: We document some crucial figures on the thorny path, from cystoscopy to adopting the arthroscope as a useful orthopaedic tool. [ABSTRACT FROM AUTHOR]

• Domain walls near grain boundaries are evident in TEM for magnetized alnico. • DPC imaging serves as a reliable tool for materials magnetic structure studies. • Magnetic domain boundaries could be visible in conventional TEM. • Magnetic observations in conventional TEM are related to higher defocus values. In this work, non-Lorentz, Lorentz transmission electron microscopy (LTEM) and differential phase contrast (DPC) methods were used to observe the phase and magnetic structure of the alnico magnet. All observations were performed on alnico-5 in transverse orientation. The results showed the magnetic contrast of the domain walls in the conventional TEM images despite the effects of the lens magnetic field, which was verified and explained using DPC. Experimental methodology and sample results are summarized with advice for further research. [ABSTRACT FROM AUTHOR]

Objetivou-se discutir a relevância histórica da Comuna de Paris de 1871, ainda que um século e meio a separe do tempo presente. Para tanto, procedeu-se revisão bibliográfica de obras de autores anarquistas e comunistas e, fundamentalmente, exaustiva análise da obra de Marx, especialmente de A guerra civil na França, escrita por ocasião dos eventos da Comuna. Concluiu-se que a insurreição do proletariado, ocorrida durante a Comuna de Paris, ensejou um momento histórico decisivo de contestação da sociedade de classes, da propriedade privada e das formas burguesas de organização social. Nesse sentido, o retorno ao evento histórico da Comuna lança luzes à compreensão dos desdobramentos da sociedade capitalista, os rumos percorridos pelas lutas do proletariado e o papel ocupado pelo Estado.

We have implemented three different optical methods to quantitatively assess the thickness of thin GaSe flakes transferred on both transparent substrates, like Gel-Film, and SiO2/Si substrates. We show how their apparent color can be an efficient way to make a quick, rough estimation of the thickness of the flakes. This method is more effective for SiO2/Si substrates as the thickness-dependent color change is more pronounced on these substrates than on transparent substrates. On the other hand, for transparent substrates, the transmittance of the flakes in the blue region of the visible spectrum can be used to estimate the thickness. We find that the transmittance of flakes in the blue part of the spectrum decreases at a rate of 1.2%/nm. On SiO2/Si, the thickness of the flakes can be accurately determined by fitting optical contrast spectra to a Fresnel law-based model. Finally, we also show how the quantitative analysis of transmission mode optical microscopy images can be a powerful method to quickly probe the environmental degradation of GaSe flakes exposed to aging conditions.

Low-cost ultrasound imaging systems are desired for many applications outside of radiology and cardiology departments. By making ultrasound systems smaller and lower cost, the use of ultrasound has spread from these mainstays to other areas of the hospital such as emergency departments and critical care. To further miniaturize and reduce the cost of ultrasound systems, we have investigated novel Fresnel-based beamforming methods to reduce front-end hardware requirements. Previous studies with linear and curvilinear arrays demonstrated comparable imaging performance using Fresnel-based beamforming versus delay-and-sum (DAS) beamforming. In this work, we extend Fresnel-based beamforming to phased arrays with beam steering. To accomplish this in transmit mode, we introduce a technique called a gated transmit beamformer where multicycle bursts are gated using multiplexers. In receive mode, a 64-element 2.5-MHz phased array is broken up into four 16-element subapertures, and each subaperture performs Fresnel beamforming before a final beamforming step is done. Timing errors are inevitable with Fresnel-based beamforming leading to higher sidelobe and clutter levels. To suppress sidelobe and clutter contributions, we also combine this with our previous technique, dual apodization with cross correlation (DAX) to improve contrast. Field II simulations are performed to evaluate spatial resolution and contrast-to-noise ratio and compared to standard DAS beamforming. Fresnel-based and gated transmit beamforming is also implemented using synthetic aperture data from tissue-mimicking phantoms. Lastly, a hardware proof-of-concept (PoC) Fresnel beamformer was designed, assembled, and evaluated with images from tissue-mimicking phantoms and initial in vivo images. [ABSTRACT FROM AUTHOR]

In this work we address the distance dependence of reconfigurable intelligent surfaces (RIS). As differentiating factor to other works in the literature, we focus on the array near-field, what allows us to comprehend and expose the promising potential of RIS. The latter mostly implies an interplay between the physical size of the RIS and the size of the Fresnel zones at the RIS location, highlighting the major role of the phase. To be specific, the point-like (or zero-dimensional) conventional scattering characterization results in the well-known dependence with the fourth power of the distance. On the contrary, the characterization of its near-field region exposes a reflective behavior following a dependence with the second and third power of distance, respectively, for a two-dimensional (planar) and one-dimensional (linear) RIS. Furthermore, a smart RIS implementing an optimized phase control can result in a power exponent of four that, paradoxically, outperforms free-space propagation when operated in its near-field vicinity. All these features have a major impact on the practical applicability of the RIS concept. As one contribution of this work, the article concludes by presenting a complete signal characterization for a wireless link in the presence of RIS on all such regions of operation. [ABSTRACT FROM AUTHOR]

Robert Stephenson's 'Rocket' was the first of its kind and intentionally preserved as an icon of railway history. The Fresnel fixed optic at Hartlepool was the last of its kind and was preserved by accident. Nevertheless, like 'Rocket' it is an extraordinary survival of an artefact representing a seminal moment of a technical achievement which had a lasting influence. It thus no less an icon than the famous locomotive. Hartlepool Heugh Lighthouse was built in the mid-1840s and lit by an optic and a gas lamp, seemingly a unique combination. The burner was apparently a completely new type, producing a flame large and steady enough to exploit the refracting and reflecting characteristics of the optic, something no previous gas burner had been able to achieve. The paper considers the optic and its lamp in the context of contemporary developments in lighthouse illumination and burner design and gives an account of the history of gaslit lighthouses before Hartlepool. The construction of the lighthouse provoked a clash between the Port authorities and Trinity House and the reasons for this are examined. The optic had an astonishingly long life of nearly 80 years, remaining in service until 1927, by which time it was perceived as an historic object which should not just be discarded. The paper concludes with the story of its preservation and subsequent display by the Hartlepool Museum service. [ABSTRACT FROM AUTHOR]

• Advances control techniques play an important role in operating solar plants. • An adaptative UKF-based MPC is developed for a Fresnel Collector field. • The UKF estimates the non-measurable temperatures and the effective solar radiation. • Simulations and two real tests show the effectiveness of the proposed strategy. One of the ways to improve the efficiency of solar energy plants is by using advanced control and optimization algorithms. In particular, model predictive control strategies have been applied successfully in their control. The control objective of this kind of plant is to regulate the solar field outlet temperature around a desired set-point. Due to the highly nonlinear dynamics of these plants, a simple linear controller with fixed parameters is not able to cope with the changing dynamics and the multiple disturbance sources affecting the field. In this paper, an adaptative model predictive control strategy is designed for a Fresnel collector field belonging to the solar cooling plant installed at the Escuela Superior de Ingenieros in Sevilla. The controller changes the linear model used to predict the future evolution of the system with respect to the operating point. Since only the inlet and outlet temperatures of the heat transfer fluid are measurable, the intermediate temperatures have to be estimated. An unscented Kalman filter is used as a state estimator. It estimates metal-fluid temperature profiles and effective solar radiation. Simulation results are provided comparing the proposed strategy with a PID + feedforward series controller showing better performance. The controller is also compared to a gain scheduling generalized predictive controller (GS-GPC) which has previously been tested at the actual plant with a very good performance. The proposed strategy outperforms these two strategies. Furthermore, two real tests are presented. These tests show that the proposed controller achieves adequate set-point tracking in spite of strong disturbances. [ABSTRACT FROM AUTHOR]

Copyright of Architectus is the property of Oficyna Wydawnicza Politechniki Wroclawskiej and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The technology of small point-focusing concentrator of solar energy has been developing rapidly in recent years owing to its compact structure and high collecting efficiency. This report presents important developments of small point-focusing concentrator in the past decade. This kind of solar concentrator refers to the parabolic dish concentrator, the point-focusing Fresnel lens, and the Scheffler reflector. Technological advances of these concentrators and the related performances have been presented. There are three main mirror fabrication technologies for dish concentrator, which are high polishing metal, silver-glass mirror and vacuum-membrane. Polymethyl methacrylate is widely used as material in Fresnel lens. Many scholars have proposed new lens shape to improve the uniformity of focusing. The Scheffler reflector has a characteristic of fixed focus, but its design parameters are not perfect so current research focuses on the theoretical calculation of the mirror. In addition, typical applications of the small point-focusing concentrator in photovoltaic system, solar thermal system, solar chemical system, and day-lighting system are summarized. Upon listing the important publications in open literature, a category of main applications of such kind of solar collector is provided based on the working characteristics of the system. [ABSTRACT FROM AUTHOR]

We demonstrate potential molecular monolayer detection using measurements of surface plasmon resonance (SPR) and angular Goos-Hänchen (GH) shift. Here, the molecular monolayer of interest is a benzenethiol self-assembled monolayer (BT-SAM) adsorbed on a gold (Au) substrate. Excitation of surface plasmons enhanced the GH shift which was dominated by angular GH shift because we focused the incident beam to a small beam waist making spatial GH shift negligible. For measurements in ambient, the presence of BT-SAM on a Au substrate induces hydrophobicity which decreases the likelihood of contamination on the surface allowing for molecular monolayer sensing. This is in contrast to the hydrophilic nature of a clean Au surface that is highly susceptible to contamination. Since our measurements were made in ambient, larger SPR angle than the expected value was measured due to the contamination in the Au substrate. In contrast, the SPR angle was smaller when BT-SAM coated the Au substrate due to the minimization of contaminants brought about by Au surface modification. Detection of the molecular monolayer acounts for the small change in the SPR angle from the expected value.

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This letter proposes a new method of maintaining the half-power beamwidth (HPBW) in the H-plane for printed-strip dual-broadband dipole antenna by loading dielectric lens. The lens is perpendicularly placed in the direction of radiation from the antenna. In order to reduce the dielectric loss and volume, the Fresnel structure is used for the dielectric lens. The solution is broadband, covering the entire 2G/3G/LTE spectrum of 690–1000 MHz and 1710–2770 MHz. The measured results show that by loading lens, the HPBW is maintained at 120° without affecting the working frequency range of the antenna, and the gain is increased by about 1 dB. [ABSTRACT FROM AUTHOR]

1The goal of this work is to describes the design and development of a fresnel linear concentrator that be able to concentrate sun radiations towards a receiver tube with a concentration ratio of 11.54. The methodology applied allowed to analysis the spacing, the inclinations and the adequate widths of the mirrors that would be more convenient to obtain the highest solar concentration factor and the minimum optical and thermal losses. The design of the solar concentration collector consisted of a 3.5 m x 3.0 m x 2.65 m system with 15 mirrors, each one measuring 0.12 m wide, and a receiving center height of 2.0 m. The experimental results confirmed that the maximum process temperature of 140 °C was achieved. In addition, a thermal oil storing was 995 kJ-h available in a 6-hour (since 9:00h until 15:00h). The performance tests of the system were performed in the city of Barranquilla, with local environmental conditions. The experimental tests of the prototype finally allowed to validate the design proposed in this present work. [ABSTRACT FROM AUTHOR]

The Fresnel's wave theory of light, far from being a mere theoretical speculation, enjoyed in the nineteenth century of recognition by the scientific community. This recognition was due to its ability to explain phenomena with very good agreement with the experimental results, at least up to first order approximations in β (= V/c). Many authors have already discussed the historical background in which this theory emerged and its implications for the physics by that time, as well as the experimental evidence supporting it, but the details of how these observations and / or experiments corroborate the Fresnel optics. In this work, we show how the Fresnel wave theory is able to explain experimental observations known at his time, namely: the aberration of light, the prism and the moving mirror in the ether, Fizeau's experiment. [ABSTRACT FROM AUTHOR]

At any time of the day, a spherical mirror reflects the rays coming from the sun along a line that points to the sun through the center of the sphere. This makes it possible to build concentrated solar power(CSP) plants with fixed solar fields and mobile receivers; that is, solar fields can be significantly cheaper and simpler, but challenging tracking systems for the mobile receiver need to be implemented. The cost-cutting possibilities for this technology have been under-researched. This article describes the MOSAIC concept, which aims to achieve low-cost solar energy by boosting the benefits of spherical reflectors while addressing their challenges. This new concept proposes to build large modular plants from semi-Fresnel solar bowls. One of these modules has been designed and is under construction in Spain. This article reports the main lessons learned during the design phase, describes the advantages and challenges of the concept, details the proposed routes to overcome them, and identifies the steps needed to develop a fully competitive industrial solution.

We have developed a new, fast, and simple 3-D imaging approach referred to as Simultaneous Azimuth and Fresnel Elevation (SAFE) compounding using a bias-sensitive crossed-electrode array. The principle behind this technique is to perform conventional plane-wave compounding with a back set of electrodes, while implementing a reconfigurable Fresnel elevation lens with an orthogonal set of front electrodes. While a Fresnel lens would usually result in unacceptable secondary lobe levels, these lobes can be suppressed by compounding different Fresnel patterns. The azimuthal and elevational planes can be simultaneously compounded to increase the beam quality with no loss in frame rate. A 10-MHz, $64 \times 64$ element crossed-electrode relaxor array was fabricated on an electrostrictive one-to-three composite substrate to demonstrate the SAFE compounding approach. The electrostrictive composite array has a measured electromechanical coupling coefficient ($k_{t}$) of 0.62 with a bias voltage of 90 V and a measured two-way pulse bandwidth of 60%. The electrical impedance magnitude of array elements on resonance was measured to be $90~\Omega$ with a phase angle of −35°. Radiation patterns were simulated showing a −6-dB beamwidth of $330~\mu \text{m}$ with secondary lobe levels suppressed more than −60 dB in the azimuth dimension, and a −6-dB beamwidth of $450~\mu \text{m}$ with secondary lobe levels suppressed to −50 dB in the elevation dimension after 64 compounds. Experimental radiation patterns were collected and found to be in good agreement with simulations. Experimental 3-D images of wire phantoms were collected using a Verasonics experimental ultrasound system. [ABSTRACT FROM AUTHOR]

The concentrating photovoltaic thermal systems are of much interest among all photovoltaic thermal units which have recently been developed. The trough collectors and Fresnel lenses are more significant in case of concentrating devices, and both are the linear parabolic collectors which have been commercialized well. The numerous publications about these collectors show their importance in the efficient cogeneration of heat and power. Therefore, it is interesting to gather and discuss all the related research papers in an article to show the history as well as the latest developments in this field. This study provides a critical review on the trough/Fresnel based photovoltaic thermal systems. The chapters, containing trough and Fresnel lens, are categorized into three parts as experimental, hybrid studies, and analytical-simulation works. With this regard, the experimental works are summarized in individual tables for each mentioned category. To conclude the survey, some gaps are identified, and suggestions are recommended for future works. [ABSTRACT FROM AUTHOR]

In order to reduce the cost of the produced electricity, the Linear Fresnel Collector (LFC) system is a promising Concentrated Solar Power (CSP) technology. In this paper a detailed study is conducted aimed at the assessment of the heat losses from the receiver of a real 1 MWe pilot plant based on the Fresnel collector and cooled with a thermal oil. The receiver unit, which consists of an absorber tube and a compound parabolic concentrator (CPC), is investigated numerically in order to determine the receiver performance in different wind directions. Two receiver configurations are analyzed: a simply encapsulated one and an evacuated one. In the latter case, high vacuum conditions are reached in the gap between the absorber tube and the glass cover, whereas in the former case, air at ambient pressure fills the gap. The spatial distribution of the heat flux absorbed by the absorber tube and by the glass cover is determined by means of an optical analysis, conducted with the Monte Carlo based open-source ray-tracing tool Tonatiuh, and it is the driver of the ensuing thermal fluid dynamic analysis. A reference operation condition is studied in detail by means of a 1D model that solves the energy balance for the coolant along the entire length of the receiver. The characterization of the 1D model requires an accurate, multi-dimensional computational fluid dynamic (CFD) analysis, based on the commercial STAR-CCM+ code, which aims at determining the useful heat transferred to the coolant and the convective and radiative heat losses as a function of the oil temperature. A 2D CFD model is used to simulate the thermal behavior of the receiver at different locations along its axis in case of no wind or wind blowing across the collector axis. A 3D CFD model is adopted to study the impact of the wind blowing along the collector axis. The external air is considered in the computational domain in both CFD models, to be able to accurately assess the convective share of the heat losses. At the end, the oil temperature profile along the receiver tube, as well as the heat losses and the thermal efficiency trends, are presented and discussed. The 2D model is also exploited to perform an annual analysis, varying the solar flux and the sun position, but considering just a single wind direction. The results of our analysis indicate that the benefit of using an evacuated tube depends on the heat absorbed on the linear receiver, which depends in turn on the solar flux and on the sun position. The annual-based performance improvement obtained using an evacuated tube is not dramatic, due to the relatively low temperatures of the receiver. Moreover, this analysis also concludes that the receiver performance is only slightly affected by the wind direction and intensity up to ∼ 4 m/s, due to the presence of the CPC that protects the receiver from the external air stream. [ABSTRACT FROM AUTHOR]

Fresnel reflection on a water surface is highly variable throughout the year and can have a significant influence on building-integrated vertical PV panels, yet is generally disregarded in yield calculations. We analyze beam irradiances of two horizontal pyranometers situated next to a lake, one facing upwards and one facing downwards, to estimate the contribution of Fresnel reflection to the beam irradiance on a vertical surface. We show that in general the observed beam irradiance on the downward facing instrument matches the calculated Fresnel reflection. In contrast to other studies investigating water albedo, we also found that the reflection percentage decreases consistently with higher wind speeds and lower solar zenith angle. Fresnel reflection has the highest contribution for vertical surfaces in winter, with varying contributions between <1% and >30% of monthly global irradiance over the course of one year for different latitudes, and should thus be included in yield estimates for building integrated PV installations situated next to bodies of water. [ABSTRACT FROM AUTHOR]

We demonstrate a 3D printed holographic metasurface antenna for beam-focusing applications at 10 GHz within the X-band frequency regime. The metasurface antenna is printed using a dual-material 3D printer leveraging a biodegradable conductive polymer material (Electrifi) to print the conductive parts and polylactic acid (PLA) to print the dielectric substrate. The entire metasurface antenna is 3D printed at once; no additional techniques, such as metal-plating and laser etching, are required. It is demonstrated that using the 3D printed conductive polymer metasurface, high-fidelity beam focusing can be achieved within the Fresnel region of the antenna. It is also shown that the material conductivity for 3D printing has a substantial effect on the radiation characteristics of the metasurface antenna.

Service of digital hologram that has been recognized as a visual system for next generation requires various signal processing technologies. A transform is the most frequently used tool among signal processing techniques for 2-dimensional(D) and 3-D natural picture. A digital hologram has totally different property with a natural picture, so it is rarely efficient to apply transform tools used in 2-D image processing to a digital hologram. To overcome this a Fresnelet transform for a digital hologram has been proposed. We derive a Fresnelet transform by using the Daubechie’s filter after applying an unitary Fresnel transform to a wavelet basis function. We also implement the transform as types of device and kernel code to improve operational performance. In consideration of the average time that is required for a pixel we can have observed the performance is improved up to 242 and 30 times for using the (9,7) and (5,3) filters in case of using device code. [ABSTRACT FROM AUTHOR]

An experimental study was carried out to assess the performance of a novel bubble column humidifier operated through solar thermal energy. Different perforated plate geometries were studied experimentally to select the optimum design that delivers a low overall pressure drop in the system. Then, the day-round performance of the humidifier was investigated experimentally with and without Fresnel lens. The influence of the air superficial velocity, inlet water temperature, and inlet air relative humidity on the performance of the humidifier were investigated. Findings indicate that the average daily absolute humidity of the air at the exit of the humidifier increased by 12.3% when the air superficial velocity increased from 20 to 30 cm s-1. This absolute humidity is further increased in the range of 9%-11% with the integration of the Fresnel lens. The new humidifier design can have a direct concentrated solar thermal heating and it acts as a heater for the water and air at the same time. Subsequently, it has high performance and it can be located in remote areas. [ABSTRACT FROM AUTHOR]

Solar Thermal Electric (STE) plants can integrate Thermal Energy Storage (TES) in order to generate electricity when the energy source (Sun radiation) has vanished. TES technology has become a very important asset for this type of renewable energy source, but it has induced a rise in electricity cost in many cases. One of the reasons is the need of larger solar fields as the TES capacity increases because the solar field has to provide thermal power both to generate electricity and to charge the storage. The economic effects of improving the plant performance seem to have some internal complexities that must be investigated covering the internal relations among the main parts of a STE plant: the solar field, the power block and the energy storage. This paper presents an analytical study of these relations aimed at deriving a better understanding of the cost/performance behavior of STE plants. As the power block is a mature and commercial technology with well-established efficiencies and specific costs (in $/W, for instance), it has been taken as the reference element in modelling the plant. The other parts of the plant, i.e., the solar field and the energy storage, have been characterized in cost and energy management by a set of high-level parameters. Of course, a coarse definition cannot give very accurate results for a specific design, but it can be the guideline for the selection and sizing of a plant. It is worth noting that each type of solar thermal power plant has a different parametric scenario, corresponding to its essential design window. In this paper, comparisons among plants with different parametric scenarios are restricted to one-axis concentration solar fields, where the coarse model is easily characterized. The results show that the optimum plant configuration, in terms of TES capacity and solar field size, depends on the solar field and TES costs relative to power block cost. Moreover, it is shown that some parametric scenarios always lead to an increase in the cost of electricity when the energy storage capacity is enlarged. On the contrary, parametric scenarios associated to cheaper solar fields yield a much better economic result when TES is embodied in the plant. Additionally, TES efficiency is also identified as a parameter with high impact in the performance of the whole system. This result seems obvious, but the model gives numerical values that can help to optimize the selection process in a project. For instance, it is assessed that the lower the TES efficiency, the greater the relevance of reducing solar field costs is in order to obtain low electricity generation costs. As a general conclusion, the model points out that Fresnel-type solar fields are much better suited than parabolic trough collectors for integrating thermal energy storage. This implies that Fresnel plants present a higher potential to cover the peaks of electricity demand, which results into bigger profits. [ABSTRACT FROM AUTHOR]

Extensive pilot plant experimental studies for a period of one year were carried out to study the impact of climatic conditions on the operational performance of an innovative Fresnel solar collecting system. The solar measurements revealed that the total yearly Direct Normal Irradiance (DNI) on the tested site amounts to 1132 kWh/m 2 . The thermal collector efficiency, which depends on climatic conditions such as solar insolation, ambient temperature, receiver temperature as well as heat losses, ranges from 60% to 80%. The cost effectiveness when the tested Fresnel solar collection system with solar multiple of 1.0 (limited to day time operation) is combined with a commercial thermal desalination plant is compared with one completely run by fossil fuel. The breakeven fuel cost whereby the levelized cost of water of the two cases will be equal is yielded at a fuel cost of $92/bbl. When the tested Fresnel solar collection system is run at a location with a relatively high annual DNI level (1937 kWh/m 2 ), the fuel breakeven cost falls to $52/bbl. This study also revealed that combining a Fresnel solar collection system with an MED thermal desalination plant under specific climatic conditions is considered more cost effective when operated without thermal energy storage. [ABSTRACT FROM AUTHOR]

Within the FP7-InSun project three different solar process heat systems have been installed and integrated in two different industrial processes. A 1067 m 2 advanced flat plate collector field and a 130 m 2 parabolic trough system have been installed at a ham and sausage production in Austria to preheat the feed water of a steam boiler and to prepare hot water for cleaning and drying processes. A 2640 m 2 Fresnel collector field installed at a brick fabrication in Italy produces steam at 180 °C and 12 bars to heat air for a brick drying process. In this paper the experiences made during planning, installation, commissioning and regular system operation will be described and discussed together with measured performance data. Furthermore, system costs and cost improvements reached by optimization in the collector production and standardization of system integration devices are shown and discussed together with future application potentials on the basis of detailed simulation studies carried out during the project. [ABSTRACT FROM AUTHOR]

This article discusses an early example of interferometric, experimental research related to Einstein's Special Theory of Relativity. This research concerned two series of experiments on the velocity of light in moving media, conducted between 1914 and 1921 by the Amsterdam physicist Pieter Zeeman. With the first of these series, on the velocity of light in moving water, Zeeman obtained an important result that validated the so called ‘dispersion term' of the formula for the velocity of light in moving media. Less clear is the scientific objective of the second series, in which Zeeman measured the velocity of light in moving solid media. It seems that Zeeman's interest in this second series was triggered mainly by the technical challenges posed by these experiments. In this way, they reveal the increasing tendency of Zeeman's later research to be led by technical and experimental challenges, rather than by the actual scientific developments. [ABSTRACT FROM AUTHOR]