Bulk Reduction Research Articles

Design of Miniature Planar Antennas for 5G Systems

The objective of this work is the design and simulation of an antenna based on metamaterials in order to miniaturize the dimensions of planar antennas. Metamaterials have been on the rise in recent years. The new properties make it possible to envisage the realization of new electronic components with new functions. Metamaterials are artificial materials designed for different telecommunications applications in order to improve the performance of antennas in terms of efficiency, compactness and miniaturization of structures. The use of these materials offers advantages such as reduction in weight and bulk, which is beneficial for their integration into 5G telecommunications and telephony systems. The fifth generation 5G mobile network is a set of emerging global telecommunications standards, typically using high frequency spectrum, to provide network connectivity with reduced latency and higher speed and capacity than the forerunners. It is argued that the recurring communication infrastructure is very inefficient in energy and that 5G should be designed to solve this problem, increasing energy efficiency by several orders of magnitude. To meet the demands of 5G, we need radically new network architectures and technologies, such as heterogeneous ultra-dense network, massive multi-output MIMO, and millimeter wave communications. Our goal is to achieve a planar antenna based on metamaterials which must operate at the resonance frequency of 5G which is f=3.5GHz by the CST Studio Suit electromagnetic design and simulation software and Matlab calculation.

Metamaterial-Based Antenna Performance Enhancement for MIMO System Applications

This paper presents a method for designing a new two-element ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna. We propose the design of an ultra-wideband antenna has been proposed with a study of its properties. An isolation technique using well-designed metamaterials is presented to achieve the miniaturization and performance of the two antennas and ensure proper operation of the MIMO system with a very small spacing between radiating elements (λ/12) where λ is the length waves in a vacuum. The metamaterials used considerably reduce the coupling of multi-antennas. The application of these materials called split-ring resonator (SRR) on the antenna patch plane has contributed to the increase in the performance of the antenna studied in terms of S parameters, multiplexing efficiency, diversity gain (DG), radiation properties and envelope correlation coefficient (ECC). This increases the transmission rate. This antenna system offers advantages such as reduction in weight and bulk, which facilitates its integration into a receiver, dedicated to 5G and connected objects.

Simultaneously Breaking the Double Schottky Barrier and Phonon Transport in SrTiO3-Based Thermoelectric Ceramics via Two-Step Reduction.

The low powder factor (PF) of polycrystalline oxide perovskites induced by the resistive grain boundaries or known as double Schottky barrier (DSB) greatly restricts their thermoelectric performance in application. Here, a general protocol including (i) powder and (ii) bulk reduction in H2/Ar forming gas is demonstrated to break the DSB in La and Nb codoped SrTiO3. While the powder reduction guarantees a high carrier concentration by fully stimulating the donor doping effect, the bulk reduction effectively lowers the DSB by influencing the point defects at grain boundaries, which is proved by the combination of cathode luminescence spectra and energy-dispersive X-ray spectroscopy in transmission electron microscopy. The Hall mobility can approach 10 cm2 V-1 s-1 after two-step reduction, which is similar to the level of single crystals. However, the Seebeck coefficient is not compromised, giving rise to high PF values up to 1.70 mW m-1 K-1 under proper reduction strength. Meanwhile, the reduction process also promotes mild precipitation of Nb nanoparticles, thus effectively lowering the lattice thermal conductivity by scattering phonons. As a result, a remarkable figure of merit reaching 0.4 at 700 K is obtained, which validates the two-step reduction as a reliable strategy toward "electron crystal-phonon glass" behavior in SrTiO3-based perovskites.

Experimental study of heat and mass transfer for ammonia-water falling film absorption on novel S-shaped capillary tubes bundle

Compact absorber is beneficial for bulk reduction and cost-saving of absorption systems. This paper presents an experimental study on the heat and mass transfer performance of a novel absorber which consists of an S-shaped capillary coils bundle. Experiments were carried out for a practical ammonia-water absorption system under practical working conditions. The effects of operating parameters such as degree of subcooling, concentration and mass flow rate of inlet solution, as well as absorption pressure, on absorption were investigated. Specifically, with the selected pressures of 300kPa, 400kPa and 500kPa and concentrations of inlet solution of 6.6%, 15.5% and 22.4%, we obtained the heat and mass transfer coefficients ranging from 622~1945 Wm-2K-1 and 5.1~34.3×10-6 ms-1, respectively. The heat and mass transfer experimental data were processed in terms of the empirical correlations for the Nusselt and Sherwood numbers, respectively, and the correlations can fit all the experimental data with error bands of ±15%.

Micro-nanofibrillated cellulose preparation from bleached softwood pulp using chemo-refining approach and its evaluation as strength enhancer for paper properties

An industry compatible chemo-refining approach was tested for preparation of micro-nanofibrillated cellulose (MNFC) from bleached softwood pulp using sodium meta-periodate and sodium chlorite as oxidizers followed by refining in Valley beater. SEM and FTIR analyses confirmed micro-nano scale fibrillation and chemical functional group modification in laboratory prepared MNFC, respectively. The water retention value, carboxyl content and viscosity of MNFC were found comparable with imported NFC as reference (R-NFC). To evaluate MNFC as strength enhancer for paper properties, 5% MNFC addition to bleached mixed hardwood pulp showed 6% reduction in bulk with 36%, 24% and 97% increment in breaking length, burst index and double fold of the handsheets, respectively without affecting tear index and optical properties than the control. Surface properties were also improved. Pulp drainability (37°SR) after MNFC addition was found suitable for papermaking. These laboratory results confirmed the potential of MNFC as a suitable strength additive for paper quality improvement.

The UPMC Hillman Cancer Center Approach to the Management of Colorectal Cancer During the COVID-19 Pandemic Era

The UPMC Hillman Cancer Center Approach to the Management of Colorectal Cancer During the COVID-19 Pandemic Era

Synthesis and applications of titanium oxide catalysts for lower temperature CO oxidation

Carbon monoxide (CO) is one of the very poisonous gasses and major sources of CO produced into the environment by the automobile vehicles exhaust. There are various types of catalysts have been used in the catalytic converter for CO oxidation. The titanium dioxide (TiO2) is one of the best transitional metal oxides catalysts for lower temperature CO oxidation. A small amount of TiO2 was deposited on the mesoporous Al2O3 using atomic layer deposition and subsequent oxidation at the different temperatures. The lightly reduced support improves the high catalytic activity of the adparticles, a strongly reduced one quenches the CO oxidation. The quenching is due to thermally activated diffusion of Ti3+ interstitials from the bulk to the surface where they deplete the oxygen adsorbed onto the clusters by the formation of TiOx (x ​≃ ​2) structures. The additions of promoters and support in titanium oxide catalysts improved their performances and reduced their stability. The bulk reduction state of TiO2 strongly affects the catalytic activity of supported metal clusters in the chemical reactions between oxygen and other molecules. The certain attention has been paid on the recovery of TiO2 catalysts from reaction systems and their reuse for various times without losses of catalytic activity in CO oxidation. This investigation will shown scientific basis for potential design of Ti-oxide nano-particle catalysts for lower temperature CO oxidation.

C–O bond activation using ultralow loading of noble metal catalysts on moderately reducible oxides

Selective C–O activation of multifunctional molecules is essential for many important chemical processes. Although reducible metal oxides are active and selective towards reductive C–O bond scission via the reverse Mars–van Krevelen mechanism, the most active oxides undergo bulk reduction during reaction. Here, motivated by the enhanced oxide reducibility by metals, we report a strategy for C–O bond activation by doping the surface of moderately reducible oxides with an ultralow loading of noble metals. We demonstrate the principle using highly dispersed Pt anchored onto TiO2 for furfuryl alcohol conversion to 2-methylfuran. A combination of density functional theory calculations, catalyst characterization (scanning transmission electron microscopy, electron paramagnetic resonance, Fourier-transform infrared spectroscopy and X-ray absorption spectroscopy), kinetic experiments and microkinetic modelling expose substantial C–O activation rate enhancement, without bulk catalyst reduction or unselective ring hydrogenation. A methodology is introduced to quantify various types of sites, revealing that the cationic redox Pt on the TiO2 surface is more active than metallic sites for C–O bond activation. Reducible metal oxides selectively catalyse the hydrodeoxygenation of C–O bonds in bio-based aromatic molecules, although they show limited performance. Now, using TiO2 as an example, a method is reported to enhance the activity of the oxide by surface doping with an ultralow loading of Pt.

Self-sustained Oscillations in Oxidation of Propane Over Nickel: Experimental Study and Mathematical Modelling

The regular reaction rate oscillations were observed by mass-spectrometry in the oxidation of propane over the Ni foil. CO, CO2, H2, and H2O were detected as products. The oscillations of products and reactants in the gas phase were accompanied by the oscillations of the catalyst temperature. It was shown by using isotopic labeling 18O2 that CO and CO2 formed simultaneously by the propane oxidation when the catalyst was in the highly active state. The non-isothermal model of a continuous stirred-tank reactor based on a microkinetic scheme including 50 reaction steps was developed. The model takes into account periodic oxidation and reduction of nickel and formation of main products. Using the method of quasi-steady-state approximations, it was shown that the observed self-sustained oscillations are associated with periodic changes in the coverage of the Ni surface by adsorbed oxygen and carbon as well as nickel oxide species. It was shown that the microkinetic scheme coupled with a continuous stirred-tank reactor model qualitatively describes the experimental data if the model also considers the periodic processes of oxidation and reduction of the Ni bulk.

Low consistency refined ligno-cellulose microfibre: an MFC alternative for high bulk, tear and tensile mechanical pulp papers

Low consistency (LC) refining of (chemi-)thermomechanical pulp (TMP) provides an energy efficient alternative to high consistency refining for pulp property development. However, the benefit of LC refining is often limited by excessive fibre shortening, lower tear strength and a reduction of bulk caused by the refining process. In this study, microfibres produced by LC refining of TMP and kraft pulp fibres were investigated for their reinforcement potential in high freeness mechanical pulp. Primary pulp at 645 mL Canadian Standard Freeness was LC refined to different energy targets as a baseline for mechanical and optical property development. In contrast, the same primary pulp was reinforced with different microfibre types in ratios that yielded the same specific energies of the baseline LC refined pulp. The study revealed that at equivalent energies, the addition of TMP microfibres to the high freeness primary pulp displayed tensile development identical to the LC refined pulp, with significantly improved tear and bulk. The addition of kraft microfibre to primary pulp produced the highest tensile and tear strength but compromised light scattering. Additionally, all microfibre composites showed improved elongation, as opposed to no notable change in elongation with conventional LC refining. This investigation proposes an alternative, cost-effective approach for developing high bulk, high strength mechanical pulp by limiting the extent of second stage refining and using LC refined microfibres for pulp reinforcement. The high tear–high bulk open construction of the composite paper is likely to benefit boxboard and packaging applications.

Improving the interfacial properties of CZTS photocathodes by Ag substitution

Ag substitution improves the photocurrent and onset potential of CZTS/CdS/Pt photocathode to 17 mA cm−2 and 0.85 VRHE due to reduction of bulk and interface defects as well as increased depletion width.

Evidence of nutritional abnormalities in chronic obstructive pulmonary disease

Rationale Chronic obstructive pulmonary disease (COPD) is one of the major causes of global morbidity and mortality, with increased economic and social burden. One of the most evident systemic effects of COPD is nutritional abnormalities and muscle bulk reduction, leading to muscle dysfunction and wasting, with or without muscle atrophy. Aims This work aims to detect the prevalence of nutritional abnormalities in correlation to smoking status and COPD severity. Design This was a case–control study. Patients and methods The present study included 300 candidates functionally diagnosed of having COPD according GOLD 2017. All patients were subjected to history taking, clinical examination, BMI and free fat mass index (FFMI) assessment, spirometry before and after bronchodilator testing, and questionnaires, such as COPD Assessment Test, Clinical COPD Questionnaire, and Hospital Anxiety and Depression Scale. Results The study included 300 patients with COPD who are current smokers. Overall, 98% of them were males, and all were older than 40 years. Patients were classified into three groups: mild, moderate, and severe. The study found a statistically significant negative correlation between FFMI and COPD severity, whereas nonsignificant correlation with BMI. A strong statistically significant negative correlation was found between BMI and FFMI with smoking status. A positive correlation was seen between modified Medical Research Council scale with BMI and FFMI, but this was of nonstatistical significance. Correlation of BMI and FFMI with COPD Assessment Test score, Clinical COPD Questionnaire three domains (functional, symptoms, and mental), and Hospital Anxiety and Depression Scale (depression and anxiety) was found to have a strong positive significant correlation. Conclusion Nutritional abnormalities related to COPD and smoking should be considered while managing patients with COPD.

Remediation of chromium(VI) ions as chromium oxide xerogel via gamma-radiolysis of aqueous waste discharge

Radiolysis of water during γ-irradiation produces oxidizing and reducing species which can be used for the bulk oxidation or reduction of target toxic species. In the present work, γ-radiolysis of water has been used for the reduction of Cr(VI) to Cr(III) ions in the simulated chrome tan liquor solution samples, and simultaneously precipitation as a chromium oxide hydrate gel. Sodium formate scavenger has been found to be the best suited, among various scavengers studied, not only for the removal of oxidizing species produced during γ-radiolysis of water but also simultaneous precipitation of thus formed Cr(OH)3 as chromium oxide hydrated to gel. The chromium oxide hydrate gel has been subjected to thermal treatment for an objective of converting it to the chromium oxide xerogel which has potential applications for catalysis. Various techniques, such as BET, XRD, XPS, HRTEM and Raman spectroscopy, have been employed for studying the changes in the physical, crystalline and oxidation states in each step observed in thermal treatment starting from the hydrate gel to chromium oxide xerogel. The results showed the formation of crystalline mixed valence chromium oxide xerogel having specific surface area 20.9 m2 g−1 and pore volume 0.036 cc g−1 after thermal treatment.

Alkyl-group grafting onto glassy carbon cathodes by reduction of primary monohaloalkanes: electrochemistry and X-ray photoelectron spectroscopy studies

Surface alkylation of glassy carbon (GC) and reticulated vitreous carbon (RVC) cathodes can occur when a primary alkyl monohalide is present in solution and when the electrode is polarized at potentials more negative than those required for reductive cleavage of the carbon–halogen bond, leading to the grafting of alkyl moieties onto the surface of the carbon cathode. Examination of electrode surfaces by means of X-ray photoelectron spectroscopy (XPS) has revealed that surface sp2:sp3 carbon ratios are approximately 4:1 for both pristine GC and RVC electrode materials that are commercially available. Further XPS analysis of these electrodes before and after reduction of perfluorobutyl iodide (C4F9I) provides substantial supporting evidence for a previously proposed mechanism for the grafting process that involves an SN2-like reaction between sp2-hybridized carbon (nucleophile) of the cathode and primary alkyl halides (electrophile) leading to conversion of sp2 sites to sp3 sites, with final surface sp2:sp3 carbon ratios that fall below 1:1. At the end of this paper, we discuss (mainly in qualitative terms) the ramifications of this surface modification of GC and RVC electrodes with respect to (a) bulk reduction of primary alkyl halides and (b) use and behavior of a well-known catalyst precursor (1,2,4,5-tetracyanobenzene).

Effect of isothermal aging on the microstructure, shear behavior and hardness of the Sn58Bi/Sn3.0Ag0.5Cu/Cu solder joints

In order to decrease the hardness and brittleness of eutectic Sn58Bi (SnBi) solder joint, Sn3.0Ag0.5Cu (SAC) bulk was added into SnBi/Cu by a two-step soldering process to obtain solder joint with superposition structure. The microstructure, shear behavior and hardness of Sn58Bi/Sn3.0Ag0.5Cu/Cu (SnBi/SAC/Cu) during isothermal aging were investigated in comparison with SnBi/Cu and SAC/Cu solder joints. Experimental results indicated that the addition of SAC bulk affected the formation and growth of the β-Sn dendritic in the SnBi bulk in SnBi/SAC/Cu. The relative area and grain size of β-Sn in the SnBi bulk were enlarged due to the increasing concentration of Sn. The atomic diffusion during aging led to the volume reduction of SAC bulk in the SnBi/SAC/Cu joint. The addition of SAC bulk suppressed the brittleness of SnBi/Cu and transformed its failure mode from brittle failure to brittle-ductile failure after reflow. Such effect was weakened and the shear force and failure mode of SnBi/SAC/Cu joint were similar to those of SnBi/Cu, as the solder joints were aged for 600 h at 80 °C. Furthermore, the addition of SAC bulk significantly decreased the hardness of SnBi/Cu before and after aging.

Co-precipitated Fe-Zr catalysts for the Fischer-Tropsch synthesis of lower olefins (C2O ∼ C4O): Synergistic effects of Fe and Zr

Synthesis of lower olefins using syngas (H2/CO) in a fixed-bed reactor under 1.0 MPa, WHSV = 3 NLH2/CO·gFe-1·h-1 (WHSV = 3 NLH2/CO·gcat-1·h-1 for Zrp), H2/CO = 2 was investigated over a series of Fe-based catalysts with Zr as the promoter. The catalysts were prepared by co-precipitation (Fe and Zr) and K was impregnated into the precipitate. The prepared catalysts with different Zr/Fe mol ratio (Zr0, Zr0.2, Zr1, Zr2 and Zrp) were characterized by N2 adsorption/desorption, X-ray diffraction (XRD), Raman spectroscopy (Raman), temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). Synergistic effects of Fe and Zr on the nanostructure, textural, surface property and catalytic performance were analyzed. Characterization of the catalyst showed that the introduction of ZrO2 is in favor of the formation of mesopores due to the inhibition between Fe and Zr on each other′s crystal growth, increasing α-Fe2O3 dispersion and the proportion of surface reduction to bulk reduction, which makes the catalysts easily be reduced by H2 and CO. However, the interaction between Fe and Zr significantly suppresses the formation of θ-Fe3C and carbon deposition of catalysts. The optimal Fe/Zr mole ratio of ZrX catalysts is found to be 1/1 due to the synergistic effect of Fe and Zr, the improved distribution of α-Fe2O3 and the abundant defects on α-Fe2O3 in the catalyst. In the case of Zr1, the CO conversion and the selectivity toward lower olefins reached 82.1% and 34.6% at 270 °C. Adequate Zr, acting as a block of chain growth and weakening the adsorption of light olefins on active sites, is essential to improve the light olefins selectivity.

Sulfide-mediated azo dye degradation and microbial community analysis in a single-chamber air cathode microbial fuel cell

Several textile industry processes produce complex organics, azo dyes and sulfide streams that pose a severe challenge to environmental protection. In this work, single-chamber air cathode microbial fuel cells were used to investigate the interaction mechanisms among Congo red decolorization, sulfide oxidation and bioelectricity generation. The results showed that effective removal of sulfide (>98%) and azo dyes (>88%) was achieved at an initial sulfide/dye ratio of 0.9 under neutral conditions, accompanied by a maximum power output of approximately 23.50 mW m−2. In this study, biogenic sulfide played a major role in azo dye decolorization and power generation compared with the chemical sulfide. The results indicated that bulk reduction of sulfide and cell lysis products during biogenic sulfide production by sulfate-reduction bacteria could accelerate the chemical reduction of azo dyes. Moreover, S0, SO42− and S2O32− were identified as degradation products, and the intermediates primarily included 3,4-diaminonaphthalene-1-sulfonic acid, sodium 4-aminonaphthalene-1-sulfonate and 4, 4′-diamine biphenyl. Microbial community analysis showed that Proteobacteria (80.7%), Gammaproteobacteria (48.1%), and Dokdonella (29.5%) dominated at the phylum, class, and genus levels, respectively, of the anodic biofilm. This study offers a feasible option for the treatment of recalcitrant organics, azo dyes and sulfide pollutants using single-chamber air cathode MFCs.

Isolation of lignocellulose nanofiber from recycled old corrugated container and its interaction with cationic starch–nanosilica combination to make paperboard

In recent years, many studies have been carried out on the use of cellulose nanofiber (CNF) produced from virgin fiber as a strengthening agent for improving the physical and mechanical properties of paper, while the use of CNF isolated from bleached virgin fiber is not necessary or reasonable for many recycled/impure products. In this due, novel lignocellulose nanofiber (LCNF) was produced from inexpensive recycled old corrugated container pulp by the ultra-fine grinding technique. The diameter of the resulted LCNF was in the range of 10–80 nm, while the cellulose crystallinity index and crystallite size reduced during the process to 49% and 4 nm, respectively. Regarding the chemical composition of LCNF, no significant change was observed in comparison to OCC fiber. But, an obstacle for the application of nanofibers, especially for paperboards, is dewatering problem. Accordingly, it was tried to evaluate the potential of cationic starch–anionic nanosilica combination as a drainage/retention aid to compensate for the negative effects of applying nanofibers in the pulp suspension, meanwhile the combination enhances the gains of LCNF application. The evaluation of pulp freeness showed that the addition of 3% nanofibers reduced dewatering ability about 100 ml CSF (around 33% loss). But, interaction of the nanosilica–starch system with the furnish containing LCNF not only compensated for the freeness reduction, but also caused a 32% or 57% increase in tensile index, in comparison to sample containing LCNF or control pulp respectively. Moreover, the addition of starch–nanosilica system with LCNF to pulp suspension, improved the retention of fine materials. Also, LCNF caused a reduction in thickness, bulk and bending resistance index of paperboard, while employment of the starch–nanosilica combination somehow off-set these negative effects. In addition, as a result of the cationic starch–anionic nanosilica system, the tear index was improved.

Modeling Thermochemical Energy Storage and Release in Redox Cycles of Ca1-XSrxMnO3-Δ

Effective thermochemical energy storage (TCES) at MWh or GWh scales through reduction of oxides requires materials with 1) thermodynamic potential for significant energy storage, 2) fast reversible surface chemistry for oxygen removal, 3) rapid oxide-ion diffusion through the bulk lattice, and 4) phase and structural integrity of high-surface area structures. As reported in our previous papers (1-4)and by others (5, 6) A-site doped Ca1-xSrxMnO3-δ (x <= 0.20) provides thermodynamics for significant reduction and reversibility during redox cycles for TCES at high temperatures ≥ 700ºC. With Sr-doping levels of 5 and 10%, Ca1-xSrxMnO3-δ has demonstrated thermodynamic limits for specific TCES of 664, 737, and 877 kJ/kg at 1000ºC at P O2 ≈ 0.21, 0.01, and 10-4 bar respectively (from a zero reference state of fully oxidized Ca1-xSrxMnO3 in air at a cold temperature of 500ºC) (3). Ca0.90Sr0.10MnO3-δ and Ca0.95Sr0.05MnO3-δ were synthesized as porous particles through solid state reactive sintering to 1225ºC and tested for bulk reduction and re-oxidation at temperatures up to 1000ºC and P O2down to »10-4bar to calibrate material models for predicting specific TCES in limited residence time reactors. The particles, illustrated in Figures 1, with diameters < 450 μm, porosity ≈ 0.6, and grain sizes from 1 to 10 mm were packed into annular beds and tested in isothermal and non-isothermal redox cycling between oxidizing and reducing gases. Isothermal redox cycling of the porous particles in conjunction with TGA/DSC measurements provided the basis for fitting thermodynamically consistent surface reaction rate expressions and bulk ionic transport sub-models to measured evolution in δ. Figures 2 shows 10-cycle-averaged isothermal reduction and re-oxidation plots for a 0.6 cm bed of porous Ca0.9Sr0.1MnO3-δparticles cycled between P O2 of 0.17 and 10-4 bar. Similar results between other P O2 illustrate the significantly faster reoxidation rates that approach thermodynamic limits based on sweep-gas flow rates, suggest that neither bulk ionic diffusion nor O2 adsorption are rate-limiting at conditions tested. The packed bed experiments were simulated using a two-level internal and external dusty-gas-model for porous media transport based on measured particle and bed properties. The results showed that for typical grain sizes of 5 mm, bulk-ion transport only impacted reduction rates at temperatures ≤ 700 ºC. As such, it was difficult to fit accurately ionic diffusion parameters and further testing is required to assess more accurately ambipolar bulk diffusion models for these materials. Fitted surface chemistry rates to the experimental measurements as shown in Figure 2 does capture both the slow reduction and the fast reoxidation with a thermodynamically consistent reversible rate expression adopted from previous studies (7). The surface kinetics fitted for Ca0.9Sr0.1MnO3-δwere implemented in a one-dimensional indirect particle solar receiver model based on a narrow fluidized bed concept (8, 9)to explore the potential for how thermochemical energy storage in these particles could be coupled to designs and operating conditions for GWh energy storage systems for thermal power plants. The counterflow particles and fluidizing sweep gas at low P O2 provides a basis for reduction but rapid buildup of O2 in the gas-phase near the bottom of the bed thermodynamically inhibits reduction. As shown in Figure 3, conditions that produce particle temperatures above 1000 ºC and reduction levels with δ > 0.1 and thus provide significant specific TCES. These conditions at relatively low solid flow rates result in high wall temperatures and thus lower solar efficiency (approaching 80%) due to the wall radiation losses. Material models for Ca1-xSrxMnO3-δ permit further exploration of receiver designs to find optimal geometries and operating conditions to achieve high δ at higher solar efficiency approaching targets of 90%. References K.J. Albrecht, G.S. Jackson, and R.J. Braun, Solar Energy, 167, 179-193 (2018). L. Imponenti, K.J. Albrecht, R.J. Braun, and G.S. Jackson, ECS Transactions, 72(7), 11-22 (2016). L. Imponenti, K.J. Albrecht, R. Kharait, M.D. Sanders, and G.S. Jackson, Applied Energy, 230, 1--18 (2018). L. Imponenti, K.J. Albrecht, J.W. Wands, M.D. Sanders, and G.S. Jackson, Solar Energy, 151, 1-13 (2017). B. Bulfin, J. Vieten, D.E. Starr, A. Azarpira, C. Zachaus, M. Havecker, K. Skorupska, M. Schmucker, M. Roeb, and C. Sattler, Journal of Materials Chemistry A, 5(17), 7912-7919 (2017). N. Galinsky, A. Mishra, J. Zhang, and F.X. Li, Applied Energy, 157, 358-367 (2015). R. Merkle, Y.A. Mastrikov, E.A. Kotomin, M.M. Kuklja, and J. Maier, Journal of the Electrochemical Society, 159(2), B219-B226 (2012). G.S. Jackson, L. Imponenti, K. Albrecht, D. Miller, and R.J. Braun, Journal of Solar Energy Engineering, doi:10.1115/1.4042128 (2018). D.C. Miller, C.J. Pfutzner, and G.S. Jackson, International Journal of Heat and Mass Transfer, 126, 730-745 (2018). Figure 1

Simultaneous reduction of surface, bulk, and interface recombination for Au nanoparticle-embedded hematite nanorod photoanodes toward efficient water splitting

A novel method to reduce surface, bulk, and interface recombination simultaneously.