Search

In Part I of this diptych, we outline the parallel mode of differential phase contrast (TEM-DPC), which uses real-space distortion of Fresnel images arising from electrostatic or magnetostatic fields to quantify the phase gradient of samples with some degree of structural contrast. We present an analysis methodology and the associated software tools for the TEM-DPC method and, using them together with numerical simulations, compare the technique to the widely used method of phase recovery based on the transport-of-intensity equation (TIE), thereby highlighting the relative advantages and limitations of each. The TEM-DPC technique is particularly suitable for in situ studies of samples with significant structural contrast and, as such, complements the TIE method since structural contrast usually hinders the latter, but is an essential feature that enables the former. In Part II of this work, we apply the theory and methodology presented to the analysis of experimental data to gain insight into two-dimensional magnetic phase transitions., Microscopy and Microanalysis, 27 (5), ISSN:1431-9276, ISSN:1435-8115

We have implemented three different optical methods to quantitatively assess the thickness of thin GaSe flakes transferred on both transparent substrates, like Gel-Film, or 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., Comment: 5 figures

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.

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 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.

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.

The performance of miniature, polymer-based Fresnel liquid crystal lenses is discussed, specifically the sensitivity for non-uniformities.

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.

A scheme for wireless power transfer (WPT) in the radiative near-field (Fresnel) region is presented. The proposed Fresnel WPT scheme is designed to focus microwaves to a diffraction- limited region where a detector can be positioned, achieving reasonably high power transfer efficiency over moderate distances. The configuration consists of transmit and receive microstrip patch array antennas, with the receiving antenna connected to a power- harvesting half-wave rectifier (rectenna). Fresnel region operation enables the fields radiated by the transmitting aperture to be localized both in range and cross-range. Using Fresnel region focusing, we achieve an increase of 66.8% in the amount of received power when compared to the performance of a conventional beam-forming array. We also demonstrate the efficiency improvement by powering an LED using the on-axis and off-axis focusing configurations.

[EN] In this work, the distortion of the Fresnel Zone Plate focusing profile generated by a piston emitter in ultrasound applications is significantly reduced through the use of phase correction rings, which compensate the effect of the piston emitter radiation diagram. Both simulation and experimental results demonstrate the improvement achieved with this design method over the conventional case., This work has been supported by Spanish MINECO (TEC2015-70939-R).

Solar Heat for Industrial Processes (SHIP) can contribute significantly to a sustainable industrial energy supply. Especially in Jordan, where irradiation and fuel prices are high SHIP is a promising opportunity for industry. Also the pharmaceutical sector, which plays an important role in Jordan, has a substantial heat demand. Industrial Solar installs a first system for SHIP in Jordan at RAM Pharma, a pharmaceutical company in Sahab, Jordan. The system will be comprised of 18 LF-11 Industrial Solar Fresnel collector modules and will be operated for direct steam generation.

Several forms of renewable energy have in the last decade achieved a remarkable technological improvement and cost effectiveness, including Solar Energy. Photovoltaic systems (PV) are reaching grid parity in the sunniest regions of Europe. Apart from PV, a promising technology is Concentrated Solar Power (CSP) with thermal storage, because it enables higher power plant availability throughout the year as well as dispatchability, a highly important and valuable feature for a power plant. However significant cost reductions are still to be achieved, for CSP to be competitive with conventional electricity production and with PV. In this paper a few technological improvements are described and a proposal is made to combine them in a system that is more efficient and has, simultaneously, the potential of being cheaper. The goal is to show the potential for advanced LFR concepts in combination with high temperature molten salt mixtures and energy storage as being also important contenders to the objective of bringing STE- Solar Thermal Electricity to the market in a competitive way. The concept presented and developed includes a higher ΔT of the heat transfer fluid (HTF), a particular storage strategy and a new optical concept based on a new Linear Fresnel Concentrator (LFR XX SMS-Simultaneous Multiple Surface, Fig.1,2, [1] enabling an important increase in the overall yearly solar to electricity conversion efficiency and generating an important potential for electricity cost reduction. It is shown that values approaching 10eurocents/kWh, for a 50MW plant with 7 hours storage capacity are possible in Southern Europe.

In this paper, a deep investigation upon levelized cost of heat (LCOH) produced by small-scale solar linear concentrating Fresnel collectors (CSLFC) is proposed. Solar industrial process heat applications have temperature requirements from about 60°C to 260°C. CSLFCs can effectively integrate conventional fossil fuel thermal systems. The study is addressed to assess technology cost projection needed to achieve competitive LCOH. So, on the basis of a framework specifically developed for these economic assessments, the best investment scenarios, in terms of industrial application, geographical location and technical design solutions, where to effectively apply the technology of CSLFC, are highlighted. The analysis has been focused on specific cost of several existing CSLFCs associated with declared performances at different operating temperatures. Two main classes of CSLFC with different total efficiency (optical and thermal) corresponding to various design solutions and specific cost were selected. The expected performances in the whole application temperature range have been evaluated through Glayx Tech proprietary simulation code, including optical and thermal unsteady analysis. A huge database coming from full CSLFC simulation varying latitude, yearly DNI, operating fluid, outlet temperature, thermal storage options, has been collected. CLSFC design and performance requirements are the key-choice to achieve competitive LCOH: the use of high efficiency - high cost components is not always rewarding in terms of final LCOH and must be attentively decided basing on site, irradiation, heat quality and LCOH target. In this perspective, CLSFCs are the most promising for industrial small scale heat applications since they show the greatest potential to reduce manufacturing costs. © 2013 The Authors.

Durr is one of the world's leading suppliers of products, systems and services, mainly for automobile manufacturing. The range of products and services covers important stages of vehicle production. As a systems supplier, Durr plans and builds complete paint shops and final assembly facilities. Industrial Solar – formerly known as Mirroxx – is the leading manufacturer of Fresnel process heat collectors and can look back on seven years operating experience with its systems. Automotive industry is under considerable strain to make their products more environmentally sound. Not only the cars themselves, but also the whole value chain has to become more sustainable. One production process, which contributes a significant share to the carbon footprint of a car, is the curing of a car's paint. As the temperatures in the convection ovens are up to 200 °C the application of market available flatplate or vacuum tube collectors was not an option, as these collector types cannot provide such high temperatures. Also the thermal power needed for a convection oven is well above the typical power range of solar collectors, which were originally designed for domestic hot water applications. A pilot system of a solar driven convection oven has been installed on the Durr Campus in Bietigheim-Bissingen near Stuttgart/Germany. An Industrial Solar Fresnel collector consisting of six modules with a total aperture area of 132 m2 heats pressurized water to an outlet temperature of 180 °C. A fossil fired backup boiler complements the solar thermal system to meet the thermal power demand of the convection oven. Finally the heat is dissipated in the convection oven via a pressurized water – air heat exchanger.

To develop concentrating photovoltaic systems for building integration applications, two optical devices are proposed. The concentrators are based in stationary linear Fresnel lenses and secondary CPC. The moving focal area is ten times smaller than the Fresnel lens aperture. Concentrator characteristics are studied in detail: shadowing effect, placement of the focal area and optical concentration efficiency. The main contribution of this paper is the three-dimensional optical analysis of the non-imaging concentrating systems. In terms of solar radiation, photovoltaic moving modules placed in the focal area of stationary concentrators are compared with simply fixed photovoltaic modules. In favourable weather locations, the beam radiation incident on the concentrating modules would be a large percentage, more than 50%, of the global radiation received by the fixed photovoltaic devices.

A unique Fresnel prototype is currently running in France. It is composed of a 1000 m 2 solar field, a thermocline thermal storage and an Organic Rankine Cycle (ORC). This CSP plant is perfectly suited to test the three main parts of a solar power plant (ie. solar field, storage and turbine). More than two years of experience is achieved and the paper aims at presenting some results about this operating period. It shows that this kind of technology is very versatile. Automation experiences along with thermocline behavior are discussed. Electricity production using the storage capacity is also presented. This experimental tool will be upgraded with water chilled production and desalination. The perspective is the optimization of the whole system for MW scale installations.

This paper describes design of daylight collectors using multiple Fresnel lenses, each facing the sun for a particular period of time in a day. The influence of solar movement on flat Fresnel lens was studied. The influence of groove density of the lens was also determined by which the suitable Fresnel lens was selected. Passive and profiled north-facing and south-facing collectors with multi-lens system have been designed based on the solar altitude and azimuth angle of a geographical location. Performance of the north- and south-facing collector at different times of a day with an acrylic dome indicated better efficiency and uniformity of lighting throughout the day time for the proposed profiled Fresnel collectors. � The Chartered Institution of Building Services Engineers 2014.

SPIE OPTO, 2017, San Francisco, California, United States, Giichi Shibuya, Shohei Yamano, Hiroyuki Yoshida, and Masanori Ozaki "Active liquid-crystal deflector and lens with Fresnel structure", Proc. SPIE 10125, Emerging Liquid Crystal Technologies XII, 101250V (15 February 2017). DOI: https://doi.org/10.1117/12.2261113, A new type of tunable Fresnel deflector and lens composed of liquid crystal was developed. Combined structure of multiple interdigitated electrodes and the high-resistivity (HR) layer implements the saw-tooth distribution of electrical potential with only the planar surfaces of the transparent substrates. According to the numerical calculation and design, experimental devices were manufactured with the liquid crystal (LC) material sealed into the sandwiched flat glass plates of 0.7 mm thickness with rubbed alignment layers set to an anti-parallel configuration. Fabricated beam deflector with no moving parts shows the maximum tilt angle of ±1.3 deg which can apply for optical image stabilizer (OIS) of micro camera. We also discussed and verified their lens characteristics to be extended more advanced applications. Transparent interdigitated electrodes were concentrically aligned on the lens aperture with the insulator gaps under their boundary area. The diameter of the lens aperture was 30 mm and the total number of Fresnel zone was 100. Phase retardation of the beam wavefront irradiated from the LC lens device can be evaluated by polarizing microscope images with a monochromatic filter. Radial positions of each observed fringe are plotted and fitted with 2nd degree polynomial approximation. The number of appeared fringes is over 600 in whole lens aperture area and the correlation coefficients of all approximations are over 0.993 that seems enough ideal optical wavefront. The obtained maximum lens powers from the approximations are about ±4 m-1 which was satisfied both convex and concave lens characteristics; and their practical use for the tunable lens grade eyeglasses became more prospective.

Fresnel mirror in thermodynamic solar power plant technology is an efficient power resource in many potential countries. The key challenge is cost effectiveness of the product and its settling. The importance of using this tech- nology redounded in writing this paper to propose a methodology in order to design this system considering its complexities. Because of the dependency of the product with process of production and installation of this solar plant, a simultaneous design methodology is required. Moreover, a concept of movable factory, from one solar farm site to another one, is also discussed which is iden- tified as a proper solution for such project with reusability.

X-ray microscopy has emerged as a powerful and versatile imaging technique in many fields of science over the last years, offering insights in opaque media at high spatial resolution. A major challenge remains the fabrication of suitable X-ray lenses, e.g., Fresnel zone plates or compound refractive lenses. In an alternative approach of a lensless imaging scheme the sample is illuminated by a coherent X-ray beam. The sample information is then reconstructed from the recorded diffraction signal by numerical iterative algorithms. Within this thesis the basics of lensless holographic imaging with X-Ray waveguides are summarised and extended to the concept of waveguide-based X-ray interferometry. The specific instrumentation required for the conceptual experiments of waveguide-based holographic imaging is explained and illustrated by the obtained results. Based on the results of these conceptual experiments a dedicated synchrotron endstation for waveguide-based holographic imaging was designed and built. The specifications and properties of the Kirkpatrick-Baez focussing mirrors and other mechanical and optical components are described in detail, along with the instrument control system and various available detectors. First commissioning results prove the imaging abilities of the presented endstation.

The present paper studies the heat loss of a linear absorber with a trapezoidal cavity and a set of pipes used for a linear Fresnel reflecting solar concentrator. The study includes the measurements on a 1.4 m long prototype installed in a laboratory, and its thermal simulation in steady-state using EnergyPlus software. Results of the measured vertical temperature variation inside the cavity, the surface interior and exterior wall and window temperatures, the global heat loss at steady-state and the heat loss coefficients, are presented for six different temperatures of the pipes. Measurements revealed a stable thermal gradient in the upper portion of the cavity and a convective zone below it. Around 91% of the heat transferred to outdoors occurs at the bottom transparent window, for a pipe temperature of 200 °C. The heat loss coefficient per area of absorbing pipes ranged from 3.39 W/m2K to 6.35 W/m2K (for 110 °C < Tpipe < 285 °C), and it increased with the increase of Tpipe. Simpler and less time-consuming available free software originally designed for heat transfer in buildings was tested to be a possible replacement of the highly complex CFD software commonly used to simulate the steady-state heat loss of the absorber. The experimental and predicted data sets were found to be in good agreement. © 2011 Elsevier Ltd. Fil: Flores Larsen, Silvana Elinor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina Fil: Altamirano, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina Fil: Hernández, Alejandro Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina

KRAMER GmbH, a German supplier for cold room construction, insulation technology and shopfitting with more than 80 years of company experience, and INDUSTRIAL SOLAR GmbH (ISG), a supplier of high-quality solar process heat systems for industrial applications, and the FRAUNHOFER INSTITUTE FOR SOLAR ENERGY SYSTEMS (ISE) are currently developing a standard solar driven cold room for industrial cooling applications. Within the recent EU co-funded project SOLERA, ISE and ISG had gathered experience in the successful operation of the solar cooling technology. Main components of the SOLERA demonstration system are a linear Fresnel collector providing the driving heat at temperatures up to 200 °C for two cascading ammonia water absorption chillers, which produce cold temperatures down to -12 °C, as well as ice storages for peak shifting. In the current project AgroKuhl, which is co-funded by the German Federal Ministry of Education and Research, a consortium of five partners, among them the company KRAMER GmbH and ISE, constructed a cold room, that will now be driven by a similar solar cooling system. Further technical details, operation experience and measurement data from the SOLERA demonstration system in 2011 as well as a description of the new system will be presented in the paper.

A greenhouse with Fresnel lenses in the south facing roof and a receiver for concentrated Photovoltaics with water cooling (CPVT system) will result in electrical and thermal energy output from the solar energy excess entering a greenhouse. The PV system converts about half of the direct radiation into heat and electricity. During periods with direct radiation this will significantly reduce the heat load on the greenhouse. For an optimal performance the roof elements must be asymmetric with a steep inclination at the north side (the exact angle of course depends on the latitude of the building site). The Fresnel lens structure is best oriented in upwards direction. In the current design, two lenses are placed in the inner space of a double glass. This prevents pollution and condensation on the lenses. By the upward facing of the lens structure, the focus quality is preserved over a much broader range of angles of incidence compared to a lens with downward facing structures. Each PMMA lens with a size of 1.20×1.52 m is composed of 12 ‘tiles’ for easy production. The focal distance of the lens is 1,875 m and the geometrical concentration factor is 50×. This means that in most cases the focus line is thinner than 3 cm. The performance of the lens with respect to the shape of the focal area and the position of the focal line has been analyzed with ray tracing techniques. From this analyses and by the development of a smart tracking system only two motors can bring the receivers in the required positions. One motor controls the distance between lens and receiver and the other controls the translocation of the receivers parallel to the lens. The second conclusion was that the positions of the focal line are within the bounds of the greenhouse construction for almost the whole year. Only in winter, in the early morning and at the end of the day, the focal line will be unreachable. The 480 m2 greenhouse, with the LCPVT system based on Static Fresnel lenses and a 40 m CPVT-module and a 200 m CT-module, is designed by Bode Project Engineering and constructed by Technokas in Bleiswijk the Netherlands.

Cataloged from PDF version of article. We present a digital integral imaging system. A Fresnel lenslet array pattern is written on a phase-only LCoS spatial light modulator device (SLM) to replace the regular analog lenslet array in a conventional integral imaging system. We theoretically analyze the capture part of the proposed system based on Fresnel wave propagation formulation. Because of pixelation and quantization of the lenslet array pattern, higher diffraction orders and multiple focal points emerge. Because of the multiple focal planes introduced by the discrete lenslets, multiple image planes are observed. The use of discrete lenslet arrays also causes some other artifacts on the recorded elemental images. The results reduce to those available in the literature when the effects introduced by the discrete nature of the lenslets are omitted. We performed simulations of the capture part. It is possible to obtain the elemental images with an acceptable visual quality. We also constructed an optical integral imaging system with both capture and display parts using the proposed discrete Fresnel lenslet array written on a SLM. Optical results when self-luminous objects, such as an LED array, are used indicate that the proposed system yields satisfactory results. © 2011 Optical Society of America

Computation of a binary spatial light modulator (SLM) pattern that generates a desired light field is a challenging quantization problem for which several algorithms have been proposed, mainly for far-field or Fourier plane reconstructions. We study this problem assuming that the desired light field is synthesized within a volumetric region in the non-far-field range after free space propagation from the SLM plane. We use Fresnel and Rayleigh-Sommerfeld scalar diffraction theories for propagation of light. We show that, when the desired field is confined to a sufficiently narrow region of space, the ideal gray-level complex-valued SLM pattern generating it becomes sufficiently low pass (oversampled) so it can be successfully halftoned into a binary SLM pattern by solving two decoupled real-valued constrained halftoning problems. Our simulation results indicate that, when the synthesis region is considered, the binary SLM is indistinguishable from a lower resolution full complex gray-level SLM. In our approach, free space propagation related computations are done only once at the beginning, and the rest of the computation time is spent on carrying out standard image halftoning. (C) 2011 Optical Society of America

The usage of Fresnel diffraction as an approximation of the Kirchhoff formula offers a large variety of advantages concerning diverse calculations for camera systems. However, Fresnel approximations cannot be applied to arbitrary camera systems. For configurations with wide aperture, e.g., the usage of Fresnel approximation is not possible without accepting an unagreeable deviation. It is important to check in advance if a camera system allows such an approximation for the needed calculations. Assuming that focal length f and ground distance g are given quantities, investigations of the real and complex integrands lead to a formula from which the minimal F-number f # (respectively the maximum aperture radius r) is derived, so that Fresnel approximations can still be applied to a system. The analytical results are supported by numerical calculations and audited for three camera configurations outlined for remote sensing.

In this paper we present an approach to automatic generation of GUI for browsing of RDF data based on observation of existing forms and their adaptation to available RDF graphs. The objective of such an approach is the rapid prototyping of forms and their associated queries by exploiting the vast amount examples that is already available from the Web, and trying to automate those steps requiring human intervention (form template extraction, query specification) for customizing found examples to developer’s specific needs.

Date of Conference: 22-24 April 2010 As computer generated holograms becomes more common, the fast computation of holographic interference patterns in digital environment becomes a necessity. Since the computation time of holograms via Fresnel (or Rayleigh-Sommerfeld) diffraction models makes real time applications impossible, the holographic stereograms are developed to be a solution for this problem. Holographic stereograms divide the hologram plane into segments. In phase added stereograms the coordinates of 3D source points are used while calculating the diffraction field. And that enables to calculate the diffraction field with appropriate sized FFTs. Although the phase added stereograms are advantageous in terms of computation time, the quality of the reconstructed three dimensional images may not be satisfactory. The main reason is that the diffraction field of a given point source is approximated as a pure complex sinusuoid in each segment. To increase the reconstruction quality, we propose a method that uses variable sized segments, as opposed to previously developed holographic stereograms that use fixed sized segments. While approximating the diffraction field of a point source, higher frequency regions are covered with smaller segments and lower frequency regions with larger segments. As a result of this, we keep the total number of oscillations of pure sinusoidal waves constant in each segment. The simulations that we carried out for a point source show that we are able to obtain better quality reconstruction with our method. ©2010 IEEE.

In Argentina there exist children's dining rooms where infants and their mothers take lunch at noon and glasses of milk in the afternoon. These dining rooms are established in rural or marginal urban areas. Solar ovens are an interesting option for cooking with less expense of money, and they diminish environmental impact in these zones. A solar oven with downward and upward solar gain was built and tested. Upward solar gain is through Fresnel reflectors. The use of Fresnel reflectors resulted in higher heating power as compared to a solar oven with upper reflectors only. The performance with different numbers of Fresnel units was compared with a single-reflector solar oven with no lower Fresnel reflectors. Oven power was analysed and the result indicates that power grows as the number of Fresnel reflectors increases: it grows by 55% using 3 to 9 Fresnel reflectors, and by 34.6% with 3 to 6 Fresnel reflectors. These values are enough to cook several rations of food, and make this oven appropriate for use in dining rooms in developing countries. Fil: Esteves Miramont, Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina Fil: Quiroga, Viviana Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina Fil: Cuitiño Rosales, Maria Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina Fil: Buenanueva, Jose Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina

We propose an optical element: a phase-shifted Fresnel axicon for generation of multiple Bessel beams. By giving a binary phase modulation to the standard Fresnel axicon, the proposed element is generated. The phase profile of the binary phase modulation is engineered to generate two and three Bessel beams of equal intensities. This composite optical element is fabricated using electron beam direct writing. The performance of the fabricated device is evaluated using a semiconductor laser, and the generation of two and three Bessel beams is successfully demonstrated. � 2012 Optical Society of America.

System and component improvements and further development of the HelioFocus dish are described, which is the largest point-focusing concentrator worldwide. An overview of the innovative system is given and enhancements of concentrator, turn table, receiver and heat transfer are shown. Testing of new components and assemblies was conducted at the prototype dish in Israel. A demonstration plant with eight units was erected in China and shall be extended in further steps. Another demonstration plant in Israel is under construction, and several more projects are being developed.

To this day solar technologies do not cover a significant share of the industrial steam demand, despite the fact that concentrating solar collectors are market available, are well capable of reaching the required operating temperatures, and are able to generate steam directly. In addition to the low cost of fossil fuels and emission permits, other reasons for the slow market penetration of solar thermal technologies for industrial process heat applications are the lack of awareness within industry that such technologies exist, along with the lack of standard package solutions. Currently, every solar process heat system must be custom tailored and integrated with the fossil fuel fired heat source of the system. This results in considerable costs for engineering services and approval. Therefore Viessmann, a leading provider of industrial steam boilers, and Industrial Solar, a renowned manufacturer of linear Fresnel collectors and turnkey provider of solar process heat systems, have joined forces to develop a standardized solar-fossil fuel powered steam generation system for industrial applications. The two industrial partners are being supported by the German Aerospace Center, DLR, which has more than 20 years of research experience with concentrating solar thermal technologies and direct steam generation. Our conference paper provides insight into the current status of the project and the activities planned. This development is funded by the Federal Environment Ministry under the project title “SolSteam” and will form the basis for the development of a commercially available product.