Experimental Investigation of an Atmospheric-Open Cyclone Solar Reactor for Solid-Gas Thermochemical Reactions

1992 ◽  
Vol 114 (3) ◽  
pp. 171-174 ◽  
Author(s):  
A. Steinfeld ◽  
A. Imhof ◽  
D. Mischler
Keyword(s):  
Absorption Efficiency ◽  
Solar Furnace ◽  
Small Scale ◽  
Reaction Products ◽  
Concentrated Solar Energy ◽  
High Temperature Process ◽  
Energy Absorption Efficiency ◽  
Particle Separator ◽  
Solar Receiver ◽  
High Degree

A solar receiver-reactor has been designed to conduct solid-gas chemical reactions, using concentrated solar radiation as the energy source of high-temperature process heat. It consists of a conical cyclone gas-particle separator that has been modified to let concentrated solar energy enter the cavity through a windowless (atmospheric-open) aperture. It combines the advantages of cavity receivers and volumetric reactors, and permits continuous mode of operation. A small-scale prototype reactor to conduct the thermal decomposition of calcium carbonate at 1300 K was experimentally investigated in a solar furnace. Its thermal performance was evaluated. The mean energy absorption efficiency, based on the optically measured power incident on the receiver aperture, was 43 percent. Reaction products showed high degree of calcination.

Surface Hardening of Steel Using Highly Concentrated Solar Energy Process

1999 ◽  
Vol 121 (1) ◽  
pp. 36-39 ◽  
Author(s):  
A. Ferriere ◽  
C. Faillat ◽  
S. Galasso ◽  
L. Barrallier ◽  
J-E. Masse
Keyword(s):  
Solar Energy ◽  
Surface Hardening ◽  
Solar Furnace ◽  
Small Scale ◽  
Single Spot ◽  
Energy Process ◽  
Concentrated Solar Energy ◽  
Compressive Stresses ◽  
Hardening Process ◽  
Continuous Scanning

A recent French contribution in the field of surface hardening of steel using concentrated solar energy is presented. Single spot and continuous scanning processes have been investigated in a small-scale solar furnace. Hardened regions of 0.5–1.5 mm in thickness have been obtained on specimens of carbon steel, resulting from the transformation hardening process. Compressive stresses are induced in the thermally affected layer, without tensile peak in the bulk.

CO2 Splitting in a Hot-Wall Aerosol Reactor via the Two-Step Zn/ZnO Solar Thermochemical Cycle

2009 ◽  
Author(s):  
Peter G. Loutzenhiser ◽  
M. Elena Ga´lvez ◽  
Illias Hischier ◽  
Anastasia Stamatiou ◽  
Aldo Steinfeld
Keyword(s):  
Flow Reactor ◽  
Energy Conversion Efficiency ◽  
Solar Furnace ◽  
Thermochemical Cycle ◽  
X Ray Diffraction ◽  
Concentrated Solar Energy ◽  
High Temperature Process ◽  
Solar Thermochemical ◽  
Reduction Of Co2

Using concentrated solar energy as the source of high-temperature process heat, a two-step CO2 splitting thermochemical cycle based on Zn/ZnO redox reactions is applied to produce renewable carbon-neutral fuels. The solar thermochemical cycle consists of: 1) the solar endothermic dissociation of ZnO to Zn and O2; 2) the non-solar exothermic reduction of CO2 with Zn to CO and ZnO; the latter is the recycled to the 1st solar step. The net reaction is CO2 = CO + 1/2 O2, with products formed in different steps, thereby eliminating the need for their separation. A Second-Law thermodynamic analysis indicates a maximum solar-to-chemical energy conversion efficiency of 39% for a solar concentration ratio of 5000 suns. The technical feasibility of the first step of the cycle has been demonstrated in a high-flux solar furnace with a 10 kW solar reactor prototype. The second step of the cycle is experimentally investigated in a hot-wall quartz aerosol flow reactor, designed for in-situ quenching of Zn(g), formation of Zn nanoparticles, and oxidation with CO2. The effect of varying the molar flow ratios of the reactants was investigated. Chemical conversions were determined by gas chromatography and X-ray diffraction. Chemical conversions of Zn to ZnO of up to 88% were obtained for a residence time of ∼ 3.05 s. For all of the experiments, the reactions primarily occurred outside the aerosol jet flow on the surfaces of the reaction zone.

Simulation of a Solar Receiver-Reactor for Hydrogen Production

2009 ◽  
Author(s):  
Martina Neises ◽  
Felix Goehring ◽  
Martin Roeb ◽  
Christian Sattler ◽  
Robert Pitz-Paal
Keyword(s):  
Hydrogen Production ◽  
Solar Radiation ◽  
Thermal Behavior ◽  
Water Splitting ◽  
Solar Furnace ◽  
Small Scale ◽  
Mathematical Tool ◽  
Thermochemical Cycle ◽  
Set Up ◽  
Solar Receiver

The transient thermal behavior of two solar receiver-reactors for hydrogen production has been modeled using Modelica/Dymola. The simulated reactors are dedicated to carry out the same chemical reactions but represent two different development stages of the project HYDROSOL and two different orders of magnitude concerning reactor size and hydrogen production capacity. The process itself is a two step thermochemical cycle, which uses mixed iron-oxides as a redox-system. The iron-oxide is coated on a ceramic substrate, which is placed inside the receiver-reactor and serves on the one hand as an absorber for solar radiation and on the other hand as the reaction zone for the chemical reaction. The process consists of a water splitting step in which hydrogen is produced and a regeneration step during which the used redox-material is being reduced. The reactor is operated between these two reaction conditions in regular intervals with alternating temperature levels of about 800 °C for the water splitting step and 1200 °C for the regeneration step. Because of this highly dynamic process and because of fluctuating solar radiation during the day, a mathematical tool was necessary to model the transient behavior of the reactor for theoretical studies. Two models have been developed for two existing receiver-reactors. One model has been set up to simulate the behavior of a small scale test reactor, which has been built and tested at the solar furnace of DLR in Cologne. Results are very promising and show that the model is able to reflect the thermal behavior of the reactor. Another model has been developed for a 100 kWth pilot reactor which was set up at the Plataforma Solar de Almeri´a in Spain. This model is based on the first model but special geometrical features had to be adapted. With this model temperatures and hydrogen production rates could be predicted.

Energy Absorption of Origami Crash Box: Numerical Simulation and Theoretical Analysis

2018 ◽  
Author(s):  
Mengyan Shi ◽  
Jiayao Ma ◽  
Yan Chen ◽  
Zhong You
Keyword(s):  
Energy Absorption ◽  
Theoretical Study ◽  
Low Cost ◽  
Deformation Mode ◽  
Absorption Efficiency ◽  
Great Promise ◽  
Good Match ◽  
Energy Absorption Efficiency ◽  
Thin Walled ◽  
Initial Peak

Thin-walled tubes as energy absorption devices are widely in use for their low cost and high manufacturability. Employing origami technique on a tube enables induction of a predetermined failure mode so as to improve its energy absorption efficiency. Here we study the energy absorption of a hexagonal tubular device named the origami crash box numerically and theoretically. Numerical simulations of the quasi-static axial crushing show that the pattern triggers a diamond-shaped mode, leading to a substantial increase in energy absorption and reduction in initial peak force. The effects of geometric parameters on the performance of the origami crash box are also investigated through a parametric study. Furthermore, a theoretical study on the deformation mode and energy absorption of the origami crash box is carried out, and a good match with numerical results is obtained. The origami crash box shows great promise in the design of energy absorption devices.

Bending Behavior of Simply-Supported Sandwich Beams Subjected to Large Deflection

2018 ◽  
Vol 777 ◽  
pp. 569-574
Author(s):  
Zhong You Xie
Keyword(s):  
Energy Absorption ◽  
Large Deflection ◽  
Absorption Efficiency ◽  
Sandwich Beams ◽  
Element Simulation ◽  
Energy Absorption Efficiency ◽  
Load Carrying ◽  
Absorption Performance ◽  
Bending Behavior ◽  
The Moment

Due to thin skins and soft core, it is apt to local indentation inducing the concurrence of geometrical and material nonlinearity in sandwich structures. In the paper, finite element simulation is used to investigate the bending behavior of lightweight sandwich beams under large deflection. A modified formulation for the moment at mid-span section of sandwich beams under large deflection is presented, and energy absorption performance is assessed based on energy absorption efficiency. In addition, it is found that no local indentation arises initially, while later that increases gradually with loading displacement increasing. The height of the mid-span section as well as load-carrying capacity decreases significantly with local indentation depth increasing.

Developments in pesticide application for the small-scale farmer in the tropics

1981 ◽  
Vol 10 (7) ◽  
pp. 345-349 ◽  
Author(s):  
G A Matthews
Keyword(s):  
Crop Protection ◽  
Small Scale ◽  
Weed Competition ◽  
Pesticide Application ◽  
Peasant Farmer ◽  
Recent Developments ◽  
The Tropics ◽  
High Degree ◽  
Spinning Disc ◽  
Small Scale Farmer

Hydraulic sprayers, which have reached a high degree of sophistication, have long been seen as inappropriate for use in many countries where crops are most at risk from pest, disease and weed competition. ULV application by spinning-disc sprayer may have overcome problems of inadequate water supply, but, for many, costs are still too high. Recent developments in electrostatic sprayers could remove this final constraint to adequate crop protection for the peasant farmer.

scholarly journals Rocky pine forests in the High Coast Region in Sweden: structure, dynamics and history

2020 ◽  
Vol 38 ◽  
pp. 101-130
Author(s):  
Jennie Sandström ◽  
Mattias Edman ◽  
Bengt Gunnar Jonsson
Keyword(s):  
Human Impact ◽  
Fire History ◽  
Dead Wood ◽  
Forest Type ◽  
Basal Area ◽  
Pine Forests ◽  
Small Scale ◽  
Natural Dynamics ◽  
Almost All ◽  
High Degree

Almost all forests in Sweden are managed and only a small fraction are considered natural. One exception is low productive forests where, due to their limited economical value, natural dynamics still dominate. One example is the Scots pine (Pinus sylvestris L.) forests occurring on rocky and nutrient-poor hilltops. Although these forests represent a regionally common forest type with a high degree of naturalness, their dynamics, structure and history are poorly known. We investigated the structure, human impact and fire history in eight rocky pine forests in the High Coast Area in eastern Sweden, initially identified as good representatives of this forest type. This was done by sampling and measuring tree sizes, -ages, fire-scarred trees, as well as dead wood volumes and quality along three transects at each site. The structure was diverse with a sparse layer of trees (basal area 9 m2 and 640 trees larger than 10 cm ha-1) in various sizes and ages; 13 trees ha-1 were more than 300 years old. Dead wood (DW), snags and logs in all stages of decay, was present and although the actual DW (pine) volume (4.4 m3 ha-1) and number of units (53 ha-1) was low, the DW share of total wood volume was 18% on average. Dead wood can be present for several centuries after death; we found examples of both snags and logs that had been dead more than 300 years. Frequent fires have occurred, with an average cycle of 40 years between fires. Most fires occurred between 1500-1900 and many of them (13) during the 1600s. However, fires were probably small since most fire years were only represented at one site and often only in one or a few samples. The rocky pine forests in the High Coast Area are representative of undisturbed forests with low human impact, exhibiting old-growth characteristics and are valuable habitats for organisms connected to sun-exposed DW. Management of protected rocky pine forests may well include small-scale restoration fires and the limited DW volumes should be protected.

scholarly journals Heat Treatment of Steel 1.1730 with Concentrated Solar Energy

2019 ◽  
Vol 56 (1) ◽  
pp. 261-270
Author(s):  
Maria Stoicanescu ◽  
Aurel Crisan ◽  
Ioan Milosan ◽  
Mihai Alin Pop ◽  
Jose Rodriguez Garcia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Solar Radiation ◽  
Solar Energy ◽  
Vertical Axis ◽  
Solar Furnace ◽  
Solid Base ◽  
Heating And Cooling ◽  
Concentrated Solar Energy ◽  
Wide Range ◽  
The Impact

This paper presents and discusses research conducted with the purpose of developing the use of solar energy in the heat treatment of steels. For this, a vertical axis solar furnace called at Plataforma Solar de Almeria was adapted such as to allow control of the heating and cooling processes of samples made from 1.1730 steel. Thus temperature variation in pre-set points of the heated samples could be monitored in correlation with the working parameters: the level of solar radiation and implicitly the energy used the conditions of sample exposed to solar radiation, and the various protections and cooling mediums.The recorded data allowed establishing the types of treatments applied for certain working conditions. The distribution of hardness, as the representative feature resulting from heat treatment, was analysed on all sides of the treated samples. In correlation with the time-temperature-transformation diagram of 1.1730 steel, the measured values confirmed the possibility of using solar energy in all types of heat treatment applied to this steel. In parallel the efficiency of using solar energy was analysed in comparison to the energy obtained by burning methane gas for the heat treatment for the same set of samples. The analysis considered energy consumption, productivity and the impact on the environment. Thanks to various data obtained through developed experiences, which cover a wide range of thermic treatments applied steels 1.1730 model, we can certainly state that this can be a solid base in using solar energy in applications of thermic treatment at a high industrial level.

scholarly journals Printable microscale interfaces for long-term peripheral nerve mapping and precision control

2019 ◽  
Author(s):  
Timothy M. Otchy ◽  
Christos Michas ◽  
Blaire Lee ◽  
Krithi Gopalan ◽  
Jeremy Gleick ◽  
...  
Keyword(s):  
Peripheral Nerves ◽  
Small Animal ◽  
Implantable Devices ◽  
Small Scale ◽  
Current Steering ◽  
Channel Current ◽  
Bioelectronic Medicine ◽  
Small Animal Models ◽  
High Degree

ABSTRACTThe nascent field of bioelectronic medicine seeks to decode and modulate peripheral nervous system signals to obtain therapeutic control of targeted end organs and effectors. Current approaches rely heavily on electrode-based devices, but size scalability, material and microfabrication challenges, limited surgical accessibility, and the biomechanically dynamic implantation environment are significant impediments to developing and deploying advanced peripheral interfacing technologies. Here, we present a microscale implantable device – the nanoclip – for chronic interfacing with fine peripheral nerves in small animal models that begins to meet these constraints. We demonstrate the capability to make stable, high-resolution recordings of behaviorally-linked nerve activity over multi-week timescales. In addition, we show that multi-channel, current-steering-based stimulation can achieve a high degree of functionally-relevant modulatory specificity within the small scale of the device. These results highlight the potential of new microscale design and fabrication techniques for the realization of viable implantable devices for long-term peripheral interfacing.

Compressive Properties of Electroless Ni-P Coating Reinforced Magnesium Alloy Foams

2021 ◽  
Vol 889 ◽  
pp. 123-128
Author(s):  
Sheng Jun Liu ◽  
Zhi Qiang Dong ◽  
Ren Zhong Cao ◽  
Da Song ◽  
Jia An Liu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Absorption Efficiency ◽  
Absorption Capacity ◽  
Compressive Properties ◽  
Compressive Test ◽  
Energy Absorption Capacity ◽  
Energy Absorption Efficiency ◽  
Hybrid Foams ◽  
Electroless Ni

In this study, the open-cell Mg-2Zn-0.4Y foams were prepared by infiltration casting method. The Ni/Mg hybrid foams were prepared by electroless Ni-P coating on the foam struts to improve the compressive strength and energy absorption capacity. The compressive properties of the Mg alloy foams and Ni/Mg hybrid foams were studied by quasi-static compressive test. The experimental results show that the Ni-P coating is composed of crystallites. The Ni-P coating can significantly enhance the compressive strength, energy absorption capacity and energy absorption efficiency of the foams.

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