Surface faceting and reconstruction of ceria nanoparticles

The surface atomic arrangement of metal oxides determines their physical and chemical properties, and the ability to control and optimize structural parameters is of crucial importance for many applications, in particular in heterogeneous catalysis and photocatalysis. Whereas the structures of macroscopic single crystals can be determined with established methods, for nanoparticles (NPs), this is a challenging task. Herein, we describe the use of CO as a probe molecule to determine the structure of the surfaces exposed by rod-shaped ceria NPs. After calibrating the CO stretching frequencies using results obtained for different ceria single-crystal surfaces, we found that the rod-shaped NPs actually restructure and expose {111} nanofacets. This finding has important consequences for understanding the controversial surface chemistry of these catalytically highly active ceria NPs and paves the way for the predictive, rational design of catalytic materials at the nanoscale.Postprint (author's final draft

Effect of polymer properties and adherend surfaces on adhesion

The surface properties associated with good adhesive joints were evaluated in terms of application of adhesive bonding in aerospace technology. The physical and chemical nature was determined of Ti and Al adherend surfaces after various surface treatments, and the effects on fracture surfaces of high temperature aging, and variations in amide, anhydride, and solvent during polymer synthesis. The effects were characterized of (1) high temperature during shear strength testing, (2) fiber-reinforced composites as adherends, (3) acid/base nature of adherends, (4) aluminum powder adhesive filler, and (5) bonding pressure

EFEKTIVITAS PELAKSANAAN SURAT EDARAN GUBERNUR KEPULAUAN RIAU NOMOR 420/531.1/DISDIK.SET/2020 PADA MASA PANDEMI COVID 19

Pada masa pandemi covid 19, banyak surat edaran yang dikeluarkan oleh pejabat pemerintah pusat maupun daerah. Surat edaran itupun memuat poin-poin dalam penanggulangan, pencegahan dan penyebaran covid 19. Tujuan penelitian ini adalah untuk mengetahui efektivitas  dalam pelaksanaan salah satu surat edaran yang dikeluarkan oleh gubernur kepulauan riau pada masa pandemi covid 19 yang ditujukan pada lembaga pendidikan dalam pemberian keringanan uang sekolah siswa. Penelitian ini adalah penelitian hukum empiris. Supaya penelitian ini tidak terlalu luas maka perlu ada pembatasan masalah dan penelitian ini lakukan disebuah sekolah swasta yang ada di kota batam yaitu sekolah menengah atas ananda batam.  Hasil dari penelitian ini menunjukkan bahwa pelaksanaan surat edaran gubernur kepulauan riau nomor 420/531.1/DISDIK.SET/2020 pada masa pandemi covid 19 di nilai kurang efektif, dikarenakan dalam pemberian keringanan uang sekolah kepada siswa tidak secara merata. Namun disisi lain pihak sekolah juga membutuhkan biaya besar untuk melanjutkan kegiatan operasional sekolah

Surface composition and structure of Co\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e(110) and the effect of impurity segregation

The Co3O4 (110) single crystal surface has been characterized by low energy electron diffraction (LEED), Auger electron spectroscopy, and x-ray photoelectron spectroscopy (XPS). LEED analysis of the clean Co3O4 (110) spinel surface shows a well-ordered pattern with sharp diffraction features. The XPS spectra are consistent with stoichiometric Co3O4 as determined by the concentration ratio of oxygen to cobalt (CO /CCo) and spectral peak shape. In particular, the cobalt 2p XPS spectra are characteristic of the spinel structure with Co3+ occupying octahedral sites and Co2+ in tetrahedral sites within the lattice. During prolonged heating at 630 K, bulk impurities of K, Ca, Na, and Cu segregated to the surface. Sodium desorbed from the surface as NaOH at 825 K, potassium and calcium were only removed by sputtering since no desorption from the surface was detected for temperatures up to 1000 K. Copper also disappeared upon heating above 700 K, most likely by desorbing although the possibility of diffusion back into the bulk could not be eliminated. The appearance of copper impurities correlated with Co3O4 (110) surface reduction to CoO, and the surface could not be fully reoxidized even upon extended oxygen annealing as long as the copper impurity remained on the surface. Upon removal of the Cu from the near-surface region, the surface was easily reoxidized to Co3O4 by O2

General Fund Receipts, January 4, 2011

General fund receipts, monthly report for the State of Iowa, produced by the Department of Management

ARXPS-studies ofcˆ-axis textured YBa2Cu3Ox-films

YBa2Cu3Ox sputter deposited cold on MgO grows in O2 annealing epitaxially to a transparent, superconducting film with Tc 80K. The unscraped surfaces of these films are smooth showing XPS lines changing with photoelectron take-off angle. This enhanced data base allows to separate the different chemical compounds (hydroxide, peroxide, carbonate, carboxyle, cuprate, graphite ...) and to obtain their spatial distribution. This yields the compounds, their amount and distribution making up the cinder growing with O2-anneal at internal and external surfaces. The cinder stoichiometry gives insights in the chemistry going on in O2 annealing. Below the cinder the signature ofcˆ-axis oriented YBa2Cu3Ox is identified, showing that a Ba-oxide layer forms the stable surface. This coats insulating CuO2 and Y-oxide layers yielding so an intrinsic dead layer

Cross-linked CoMoO4/rGO nanosheets as oxygen reduction catalyst

Development of inexpensive and robust electrocatalysts towards oxygen reduction reaction (ORR) is crucial for the cost-affordable manufacturing of metal-air batteries and fuel cells. Here we show that cross-linked CoMoO4 nanosheets and reduced graphene oxide (CoMoO4/rGO) can be integrated in a hybrid material under one-pot hydrothermal conditions, yielding a composite material with promising catalytic activity for oxygen reduction reaction (ORR). Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used to investigate the efficiency of the fabricated CoMoO4/rGO catalyst towards ORR in alkaline conditions. The CoMoO4/rGO composite revealed the main reduction peak and onset potential centered at 0.78 and 0.89 V (vs. RHE), respectively. This study shows that the CoMoO4/rGO composite is a highly promising catalyst for the ORR under alkaline conditions, and potential noble metal replacement cathode in fuel cells and metal-air batteries

Identification of quantitative trait loci controlling root and shoot traits associated with drought tolerance in a lentil (Lens culinaris Medik.) recombinant inbred line population

Drought is one of the major abiotic stresses limiting lentil productivity in rainfed production systems. Specific rooting patterns can be associated with drought avoidance mechanisms that can be used in lentil breeding programs. In all, 252 co-dominant and dominant markers were used for Quantitative Trait Loci (QTL) analysis on 132 lentil recombinant inbred lines based on greenhouse experiments for root and shoot traits during two seasons under progressive drought-stressed conditions. Eighteen QTLs controlling a total of 14 root and shoot traits were identified. A QTL-hotspot genomic region related to a number of root and shoot characteristics associated with drought tolerance such as dry root biomass, root surface area, lateral root number, dry shoot biomass and shoot length was identified. Interestingly, a QTL (QRSratioIX-2.30) related to root-shoot ratio, an important trait for drought avoidance, explaining the highest phenotypic variance of 27.6 and 28.9% for the two consecutive seasons, respectively, was detected. This QTL was closed to the co-dominant SNP marker TP6337 and also flanked by the two SNP TP518 and TP1280. An important QTL (QLRNIII-98.64) related to lateral root number was found close to TP3371 and flanked by TP5093 and TP6072 SNP markers. Also, a QTL (QSRLIV-61.63) associated with specific root length was identified close to TP1873 and flanked by F7XEM6b SRAP marker and TP1035 SNP marker. These two QTLs were detected in both seasons. Our results could be used for marker-assisted selection in lentil breeding programs targeting root and shoot characteristics conferring drought avoidance as an efficient alternative to slow and labor-intensive conventional breeding methods