Absorber Research Articles

Exergy-based techno-economic and environmental assessments of a proposed integrated solar powered electricity generation system along with novel prioritization method and performance indices

This study focused on the two important gaps in the literature. The first is solar energy- powered electricity generation in a more economical way via the integration of flat plate solar collector (FPSC), an Organic Rankine Cycle (ORC), and an absorptional heat transformer (AHT) system. Another gap is advanced exergy analysis of the AHT cycle/ORC process based on renewable energy integration to reveal clues for improving the system. To close these gaps, a novel system including a lithium bromide AHT cycle-ORC with a FPSC system application was proposed in this study. In this proposed system, the temperature of the heat source for the ORC system was upgraded via an integration of the AHT and FPSC cycles. The main components of the AHT cycle are the condenser (ABScon), refrigerant cycle pump (P1), evaporator (EV), absorber (ABS), solution heat exchanger (SHX), absorbent cycle pump (P2), expansion valve (V), generator (Gen), ORC turbine (ORCT) and ORC condenser (ORCcon). To demonstrate the electricity production from solar energy in a more economical way thanks to the proposed system, a comparison was made with similar-scaled existing solar power plants. The results supported the main purpose of this study. The annual electricity production with the proposed system was calculated as 2601 MWh, with initial investment cost and payback period values of US$3.924 million and 4.531 years, respectively. The conventional and advanced exergy, exergoeconomic, environmental impact, and sustainability analyzes were also performed. Based on these, the novel performance parameters and prioritization method were proposed to assess the improvement potential of the system. The results indicated that SHX and FPSC had the highest exergy destruction rates (EDRs) of 23.711% and 21.849% over 5853.89 kW due to the stronger thermal and chemical reactions. Similarly, Gen, FPSC, and SHX had the highest ED cost rates (CRs) of 67.59%, 59.09%, and, 47.98%, respectively. Gen, V, and ORCcon were higher contributors to the exergy destruction rates of almost all the components. However, these showed an adverse manner for irreversibility activities. So, the temperatures of Gen and ORCcon should be optimized carefully. ABScon, P2, P1, ABS, Gen, ORCT, and ORCcon had high development priority to improve the whole system.

Evaluation of Lines and Spaces printing and general understanding of imaging with dark field low-n mask

BackgroundOne of the ways to push down resolution limits in extreme ultraviolet (EUV) lithography is to use alternative masks. New types of absorbers are being broadly investigated for current 0.33 NA as well as for high NA of 0.55.AimWe study the imaging performance of a low-n/low-k absorber (ABS) dark field (DF) mask for lines and spaces (LS) printing at 0.33 NA.ApproachExperimentally and via simulations, we investigate the use of low-n DF masks for a metal direct print application and compare low-n mask performance with Ta-based ABS masks.ResultsCompared to a Ta-based ABS mask used nowadays, the low-n DF mask brings contrast gain for dense LS. Also, for low-n masks, we observe large best focus (BF) shifts for isolated features with respect to dense features and change of bias. Hence, strong mask critical dimensions (CD) control is needed. We demonstrate how adding assist features can align BF through pitch. In addition, placing subresolution assist features (SRAFs) significantly enhances exposure latitude for semi/iso and iso-LS and improves the overlapping process window for selected cases.ConclusionsThese investigations show that low-n DF masks can enhance the imaging of LS through pitch if SRAFs are used and a good mask CD control is achieved. Our work further adds fundamental understanding to advantages observed for a metal direct print application of alternative ABS masks for the current and future EUV tools.

Design and realization of ultra‐wideband absorber from C to K band

Design and realization of ultra‐wideband absorber from C to K band

Exergy Analysis of a Natural Gas-Fired Gas Turbine Combined Cycle Power Plant with Post-Combustion Carbon Capture

Post-combustion carbon capture (PCC) plays an important role in reducing the greenhouse gas emissions. In the present study, an exergy analysis is conducted to assess the exergy destruction and exergetic efficiency of a natural gas-fired combined cycle gas turbine (CCGT) system coupled with the PCC unit. The overall exergetic performance of the system is compared against the baseline CCGT by using realistic data. The working temperature and composition of the exhaust flue gas are two critical parameters that have significant impact on the performance of the absorption liquid and equipment operation. Results show that the highest exergy destruction occurs in the combustion chamber and condenser are 15.69 MW and 11.78 MW, occupying more than 45 % of the exergy destruction of the overall system for the conventional CCGT system. For the CCGT system with PCC unit, the exergy destruction of absorber is relatively high with an exergetic efficiency of 56.18 %. The highest exergetic efficiency is found in the units of combustion chamber and heat recovery steam generator (HRSG), which are 90.23 % and 87.01 %, while the condenser has the lowest efficiency. Identification of the low efficiency component presents an opportunity for improvement of the system.

Dust and gas absorption in the high mass X-ray binary IGR J16318−4848

Context. With an absorption column density on the order of 10²⁴ cm⁻², IGR J16318−4848 is one of the most extreme cases of a highly obscured high mass X-ray binary. In addition to the overall continuum absorption, the source spectrum exhibits a strong iron and nickel fluorescence line complex at 6.4 keV. Previous empirical modeling of these features and comparison with radiative transfer simulations raised questions about the structure and covering fraction of the absorber and the profile of the fluorescence lines. Aims. We aim at a self-consistent description of the continuum absorption, the absorption edges, and the fluorescence lines to constrain the properties of the absorbing material, such as ionization structure and geometry. We further investigate the effects of dust absorption on the observed spectra and the possibility of fluorescence emission from dust grains. Methods. We used XMM-Newton and NuSTAR spectra to first empirically constrain the incident continuum and fluorescence lines. Next we used XSTAR to construct a customized photoionization model where we vary the ionization parameter, column density, and covering fraction. In the third step we modeled the absorption and fluorescence in a dusty olivine absorber and employed both a simple analytical model for the fluorescence line emission and a Monte Carlo simulation of radiative transfer that generates line fluxes, which are very close to the observational data. Results. Our empirical spectral modeling is in agreement with previous works. Our second model, the single gas absorber does not describe the observational data. In particular, irrespective of the ionization state or column density of the absorber, a much higher covering fraction than previously estimated is needed to produce the strong fluorescence lines and the large continuum absorption. A dusty, spherical absorber (modeled as consisting of olivine dust, although the nature of dust cannot be constrained) is able to produce the observed continuum absorption and edges. Conclusions. A dense, dusty absorber in the direct vicinity of the source consisting of dust offers a consistent description of both the strong continuum absorption and the strong emission features in the X-ray spectrum of IGR J16318−4848. In particular, for low optical depth of individual grains, which is the case for typical volume densities and grain size distribution models, the dust will contribute significantly to the fluorescence emission.

Absorption of Carbon Dioxide with Hot Potassium Carbonate Solution: Modeling and Statistical Analysis of Known Experimental Data

The process of absorbing carbon dioxide with an aqueous solution of hot potassium carbonate is widely used in industry for gas purification. The results of numerical modelling of the process are compared with a limited set of experimental data in well-known works. In this paper, a mathematical model of the process in a packed absorber is developed; fitting parameters are taken on the basis of processing known experimental data. The model is based on the equations of heat and mass transfer. Main characteristics: concentrations of substances and temperatures in the liquid and gas phases, depend on one coordinate z directed along the height of the absorber. The heat and mass transfer coefficients were calculated using the Onda formulas. The CO2 equilibrium at the liquid-gas interface was determined by Sechenov relation. The adequacy of the model was checked by comparing the calculations of carbon dioxide concentration along the absorber with the known experimental data not included in the sample from which the model parameters were determined. The numerical dependences of the CO2 content in the scrubbed gas on the physical characteristics of the process are obtained.

Design and Structure Analysis of Platinum Titanium Anodes for Hard Chromium Coating on Shock Absorber Piston Rod

Design and Structure Analysis of Platinum Titanium Anodes for Hard Chromium Coating on Shock Absorber Piston Rod

New active packaging for improving the shelf life and quality of tomato

Packaging materials play an important role in the quality preservation during postharvest storage and shelf life of fruits and vegetables. The properties of film can affect the gas composition and indirectly the physiology of the products. Nowadays, several additives can be used for improving the film permeability or reducing certain gases such as ethylene. The Group Research Labs of SAES Getters S.p.A. have developed, in collaboration with its affiliate company SAES Coated Films S.p.A. a highly selective packaging system for ethylene, including an integrated absorber in the form of a coating (1-2 µm), with good transparency and an additional anti-fog function, which can be deposited on various plastic films. The objective of the work was the evaluation of this new active packaging on 'cherry' type tomato berries (Solanum lycopersicum L.) during storage. The control consisted of a macro-perforated polypropylene film used for flow-pack packaging. Two experimental tests were conducted, the first during cold storage (10 ± 2 ° C) and the second at room temperature (22 ± 2 ° C). The analyses carried out included visual appearance, weight loss, gas exchanges, relative humidity, volatile organic compounds (VOC), colour, titratable acidity, refractometric index (° Brix) and the concentration of lycopene and β-carotene. The use of the innovative packaging did not alter the main quality indicators of the tomato (° Brix, acidity, colour). In general, the parameter that had the greatest impact on the product metabolism was the storage temperature. The VOC concentration was influenced by packaging film, with a greater accumulation in the samples packed with active packaging compared to the control. Moreover, the same material determined a reduction in weight loss, a greater accumulation of CO2 and a significant reduction in O2, especially at 22 °C. At the end of the storage, the berries stored in the active packaging showed higher levels of lycopene, compared to controls, and a reduction in β-carotene, indicating an active role of the packaging in modulating the content of bioactive compounds in the fruits. It can be concluded that the use of this innovative material can represent an effective tool for improving the postharvest management of tomato berries.

Experimental and numerical investigations on axial crushing of square cross-sections tube with vertical wave

In this paper, wavy square absorbers were experimentally and numerically investigated. Numerical simulations were performed with LS-Dyna software on 36 wavy absorbers and their crushing properties were extracted and compared with the simple one. The effect of different parameters, including wave height, wave depth, and wave type; either internal or external on the crushing characteristics were also investigated. To experimentally create corrugation to validate the numerical results, a set of steel mandrel and matrix along with press machines were used. Since the initial specimens were brittle, they were subjected to heat treatment and annealing to gain the required ductility for forming with mandrel and matrix. The annealing of aluminum shells resulted in a 76%increase in ultimate strain and a 60% and 56% decrease in yield and ultimate stresses, respectively. The results showed that with increasing half-wave height in wavy square absorbers, the maximum force was first reduced and then increased. It was also found that in the specimen with constant diameter and half-wave depth, an increment in the half-wave height led to an initial increase in efficiency, followed by a decline. According to the conducted investigations, the lowe maximum force can be observed in the specimen with zero half-wave depth as compared to those having a depth of 1 cm.

Vibration reduction for interaction response of a maglev vehicle running on guideway girders

As a vehicle moves on multiple equal-span beams at constant speed, the running vehicle would be subjected to repetitive excitations from the beam vibrations under it. Once the exciting frequency caused by the vibrating beams coincides with any of the vehicle's frequencies, resonance would take place on the vehicle. A similar resonance phenomenon occurs on a beam subject to sequential moving loads with identical axle-intervals. To reduce both resonant phenomena of a vehicle moving on guideway girders, this study proposed an additional feedback controller based the condensed virtual dynamic absorber (C-VDA) scheme. This condensation scheme has the following advantages: (1) the feedback tuning gains required to adapt the control currents or voltages are directly obtained from the tuning forces of the VDA; (2) the condensed VDA scheme does not need additional DoFs of the absorber to control the vibration of the maglev-vehicle/guideway system. By decomposing the maglev vehicle-guideway coupling system into two sub-systems (the moving vehicle and the supporting girders), an incremental-iterative procedure associated with the Newmark method is presented to solve the two sets of sub-system equations. From the present studies, the proposed C-VDA scheme is a feasible approach to suppress the interaction response for a maglev vehicle in resonance moving on a series of guideway girders.

Study of Lightweight Biomass Absorber for Microwave

Study of Lightweight Biomass Absorber for Microwave

Rate-Based Modelling and Validation of an Absorber and Stripper in an Amine-Based Post-Combustion CO 2 Capture Process

Carbon emissions capture and storage is regarded as an essential approach to mitigate the greenhouse effect led by carbon dioxide emissions from the fossil fuels combustion. Amine-based post-combustion CO2 capture technologies have great potential for retrofitting existing coal-fired power plants. In this paper, a mathematical model for a packed absorber and stripper in a CO2 capture process are developed. Typical aqueous monoethanolamine (MEA) with 30 wt.% concentration is selected as the absorbent. A rate-based method is implemented to represent the mass and heat transfer in carbon dioxide absorption and desorption processes. In addition, the heat of CO2 is derived by Gibbs-Helmholtz equation. In this way, the effect of chemical equilibrium and thermodynamic equilibrium on absorption capacity and absorption heat can be obtained. Finally, these models are validated by literature data in different plant operating conditions. The present mathematical models can be used to analyse the mass and heat transfer behaviour and to improve the overall performance of the CO2 process.

Porous carbon materials based on MOFs in microwave absorbing

With the rapid development of science and technology, especially the fast progress in the radar detection technology, lots of efforts have been made to obtain high performance microwave absorption materials. In recent years, carbon-based microwave absorption materials have received much attention because of their high-performance electromagnetic wave absorption performances, special microstructure and low density. However, they do not own an orderly structure, usually, and the impedance mismatching between carbon and air may hinder the incident electromagnetic waves enter into the microwave absorption materials and weaken its absorbing performance. Metal-organic frameworks (MOFs) has become a research hotspot almost in every filed of material chemistry due to its orderly structure, functional designability, etc. But the stability of MOFs is generally lower than the traditional porous materials. Under high temperature conditions, the structure may collapse in some extent. MOFs are often used as precursors to obtain target materials. After pyrolysis, porous carbon (NPC) and composite materials with relatively regular structure, a high specific surface area and a certain pore structure can be obtained, which is convenient for incorporating other materials with different loss mechanism in the NPC. At the same time, the carbonized NPC could be optimized to achieve good chemical stability, light weight, strong electromagnetic attenuation capability, and show excellent microwave absorption performance. In this paper, the properties of nanoporous carbon microwave absorption materials based on MOFs and their relationship between pore size and pore structure are discussed. Appropriate porosity provides a channel for EM waves to enter the microwave absorption materials, which helps to improve the impedance matching between electromagnetic waves and absorbers, thereby increasing the absorbing properties. The sizes and pore structures of the porous carbon microwave absorption materials also have an important effect on the interaction between the electromagnetic waves and the microwave absorption body. Three methods for synthesizing porous carbon of derived from MOFs are described, the advantages and disadvantages of these three methods are also analyzed. One is the one-step pyrolysis of MOFs for synthesis of porous carbons. The other is that the porous carbon obtained by pyrolysis of MOFs is recombined with different materials to carry on secondary calcination. The third method is introducing different nanoparticles into the micropores of MOFs before calcination, and then calcinating them together to prepare porous carbon composite microwave absorption materials. Previous studies show that the smaller the pore size, the more uniform the distribution, and the better the absorbing properties of the composite materials would be obtained. Porous carbon materials with different pore structures provide various propagation paths for electromagnetic waves to reflect and scatter in materials, resulting in different energy losses. The research status of microwave absorption of porous carbon materials based on magnetic metal MOFs, heteronuclear metal MOFs and non-magnetic metal MOFs are reviewed respectively. The microwave absorption mechanism of the porous carbon materials based on different metals MOFs examples or their influences on microwave absorption are also discussed. Porous carbon materials based on magnetic MOFs can improve the microwave absorbing properties by increasing the magnetic losses, and those based on heteronuclear MOFs combine the advantages of two or more materials, impart new chemical and physical properties to the materials and obtain high microwave absorption efficiency. The non-magnetic MOFs are carbonized to obtain non-magnetic metal oxide with low dielectric constant and their porous carbon composite materials, which could achieve excellent absorbing performance by improving impedance matching. Finally, the development trend of this kind of novel excellent absorption materials based on MOFs, with the advantages of strong loss, broad frequency bandwidth, thin thickness and lightweight, in the direction of diversification, compounding, lightweight and industrialization are prospected.

THE RESEARCH OF OPTICAL CHARACTERISTICS OF THE HONEYCOMBS

This article presents the results of the research of the optical characteristics of honeycombs. This research should be considered when using infrared drying. The research of the optical characteristics of honeycombs in all ranges of infrared radiation was carried out in a PerkinElmer Frontier FTIR spectrometer. The technique of the research and the general view of the installation during the research of the optical characteristics of honeycombs are described in the article. According to the results of the research, the spectral characteristics of honeycombs were constructed. The results of the experiment show that the honeycombs are a good absorber of IR energy, and the highest values of absorption by honeycombs of native humidity are observed at temperature ranges of 55 - 56 oC, 51 - 52 oC and 46 - 48 oC.

3D-Printed Gyroid-like Packings for Solvent-Based Absorbers

3D-Printed Gyroid-like Packings for Solvent-Based Absorbers

Theoretical study on the far-infrared perfect absorbers with SU8 based multilayered metamaterial structure

Theoretical study on the far-infrared perfect absorbers with SU8 based multilayered metamaterial structure

Experimental Analysis of Inclined Solar Water Heater with Baffles

This work presents the experimental analysis of solar water heater using baffles and flat absorber. Experiments are conducted with different water flow rates of water inside the baffled basin with the flat absorber. A flow rate of water was increased by 2, 4, and 8 times that an initial mass flow rate of water. Experimental results show that the water temperature is higher in the case of a water heater with baffles as compared to flat plate absorber. The maximum water temperature with minimum and maximum flow rates were found to be 65 C and 53 C, respectively with baffles held as path deviator. Also, the exit temperature of water depends on the solar intensity, absorber temperature and ambient condition.

Chemical Aging Resistance of Electrical Insulation Materials for Railway Passenger Train

To further improve the chemical aging resistance of Electrical Insulation Materials (EIM) for railway passenger trains, this paper prepares a modified polyvinyl chloride (PVC) with the UV Absorber (UVA) by the copper catalyzed azide-alkyne addition reaction. By analyzing the H-NMR (Nuclear Magnetic Resonance) and infrared spectrums, it is proved that UVA-modified PVC has been prepared successfully. In the end, based on the curve of the infrared spectroscopy as a function of carbonyl group content, the UV aging resistances of modified and common PVCs are compared. The findings show that the common PVC will turn into yellow after long-term ultraviolet irradiation, and the carbonyl in the compound rapidly increases, developing into severe aging; the insulationand physical structure properties has significantly deteriorated; while the modified PVC basically remains unchangedin color after 200h UV irradiation, and the carbonyl content increases at a rate much lower than the common PVC. Given the above, it is thus clear that the UVA-modified PVC prepared presents a better UV aging resistance.

Linearity response characterization of Polystyrene/ Graphene oxide nanocomposite as real-time dosimeter for therapeutic purposes

Introduction: In recent years, one of the emerging two dimensional (2D) carbon based nano- materials namely Graphene Oxide has been incorporated into polymeric matrices to enhance the electrical properties of the composites. The electrical conductivity of Graphene Oxide is excellently used in fabricating polymer-based sensors, energy-related systems, biotechnology, anti-statics, microwave absorbers, conductive coatings, and ionizing radiation dosimeters. The objective of this experimental work is to evaluate the linearity response of Polystyrene/Graphene oxide (0.1 wt%) nanocomposite as real-time dosimeter for therapeutic purposes. Materials and Methods: PS 1540 was supplied by Tabriz Petrochemical Company. Graphene oxide (GO) naopowder was prepared from US Nano Inc, and finally high purity toluene and DCM as the solvents were purchased from Merck Company. Solution processing has been used to prepare 0.1 wt% PS/GO nanocomposite for dosimetry purposes. A Picker-V9 60Co gamma-cell installed in the Secondary Standard Dosimetry Laboratory (SSDL) of Iran was used to irradiate the nanocomposite at various dose rates in the range of 98-159 mGy/min. Results: From the SEM images of fractured surfaces of PS/GO nanocomposite, the nano size scale of GOs nanoparticles can be observed as 140 nm. The plot of photocurrent versus dose rate for 0.1 wt% PS/GO was investigated. Results showed that the linearity was obtained in the range of 98-159 mGy/min with R2=1. The I-V measurements of the nanocomposite in a constant dose rate of 75 mGy/min at the SSD=80 cm were exhibited, in which the response was linear within the ±1000 V with R2=0.99, and also repeatability was examined for each measurement with the standard deviation less than 1%. Conclusion: In this experimental research, the linearity of Polystyrene/Graphene oxide nanocomposite as real-time dosimeter was carried out. Results showed that this nanocomposite exhibited a linear response in different dose rates ranging from 98-159 mGy/min that can be used as a real-time dosimeter utilized in therapeutic level.

Seawater Desulphurization of Simulated Flue Gas in Spray and Packed Columns: an Experimental and Modelling Comparison

Flue Gas Desulphurization (FGD) is a key topic for most of combustion fossil fuel plants and industrial applications. Wet processes are usually preferred when the removal efficiency required to comply with environmental regulation exceed 90 %, but their flexibility makes them useful also for lower performance requirements. Recently, seawater has been considered as a viable absorbent for FGD processes in coastal and naval applications, when SO2 concentration is below 1000 ppmv. This liquid absorbs SO2 mostly thanks to its natural alkalinity (on average 2.4 mmol/L) and, of course, is also largely available. The main costs of seawater FGD (SW-FGD) plants are related to the pumps needed to supply the required amount of liquid and the cost of wash water restoration before discharge. Corrosion related to the presence of acidic seawater is also a major issue of these units. While thermodynamic limitations cannot be overcome, process design can be optimized to improve mass transfer rates and reduce seawater requirements while keeping a suitable absorber size. In this work, we report the experimental findings achieved by our group on process design and optimization of SW-FGD units. Two different kinds of SW-FGD units were tested and compared: a spray column and a packed column with structured packing.