The treatment of early-onset scoliosis (EOS) remains one of the biggest challenges in paediatric orthopaedics. Magnetically controlled growing rods (MCGRs) have increased in popularity compared to ...traditional growing rods (TGRs), providing curve correction, spinal growth and a reduction of the associated surgical trauma. Between May 2015 and July 2022, 24 patients with EOS were treated with an MCGR system using a standardized implantation procedure. An ultrasonography- or radiography-controlled distraction of 3 mm every 3 months was performed. Whole spine radiographs were taken pre-operatively, post-operatively, and in six month interval. The Cobb angle, T1-S1 height, and growth were measured. All the patients had a dual-rod construct implantation. The mean age of the surgical patients was 8 years (6–11), and the mean follow up was 39 months (2–84). The etiology of the EOS was syndromic in six patients, congenital in two, idiopathic in three and neuromuscular in 12. One patient had a conversion from TGR, and one patient had a concomitant resection of hemivertebra. The mean preoperative Cobb angle was 69° (30–108°), postoperative was 38° (16–66°), and 38° (9–69°) at final follow-up. The mean pre-operative T1–S1 length was 289 mm, increasing to 326 mm post-operatively, and 353 mm at the final follow-up. The mean spinal growth was 64 mm (26–110 mm). Two retrieved rods were examined using X-ray photoelectron spectroscopy (XPS). A surface analytical technique to determine the surface chemistry after exposure of the rods in the body. The MCGR system represents a safe and less invasive option for the treatment of EOS.
In order to make a complete characterization of electric-arc furnace (EAF) dust, as hazardous industrial waste, and to solve its permanent disposal and/or recovery, bearing in mind both the volumes ...formed in the Croatian steel industry and experiences of developed industrial countries, a study of its properties was undertaken.
For this purpose, samples of EAF dust, taken from the regular production process in the Željezara Sisak Steel Mill between December 2000 and December 2001, were subjected to a series of tests.
The chemical composition of EAF dust samples was investigated by means of a several different analytical methods. The results from the chemical analysis show that the approximate order of abundance of major elements in EAF dusts is as follows: Fe, Zn, Mn, Ca, Mg, Si, Pb, S, Cr, Cu, Al, C, Ni, Cd, As and Hg.
Granular-metric composition of single samples was determined by applying sieve separation. Scanning electron micro-structural examination of EAF dust microstructure was performed and results indicated that all twelve EAF dusts were composed of solid spherical agglomerates with Fe, Zn, Pb, O, Si and Ca as the principal element.
The investigation of grain morphology and the mineralogical composition of EAF dust were taken by combination of high resolution Auger electron spectroscopy (HR AES), X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction analysis. The analysis of XPS-spectra determined the presence of zinc in the form of ZnO phase and the presence of lead in the form of PbO phase, i.e. PbSO
3/PbSO
4 forms.
The results of the X-ray diffraction phase analysis show that the basis of the examined EAF dust samples is made of a mixture of metal oxides, silicates and sulphates.
The metal concentration, anions, pH value and conductivity in water eluates was determined in order to define the influence of EAF dust on the environment.
The surface segregation of copper was investigated in laboratory and industrial non-oriented electrical steel sheets containing copper. The cold-rolled samples of Fe–Si–Al alloys were annealed in the ...temperature range 320–1 120 K in the ultra-high-vacuum chamber of a field-emission Auger electron spectrometer, and subsequently characterized by Auger electron spectroscopy (AES). The Cu segregation rate was estimated based on the surface concentration of Cu after annealing at a given temperature. Not surprisingly, the AES analysis showed that the intensity of the surface segregation of copper increased with increasing annealing temperature. However, thermal desorption spectroscopy (TDS) showed that above 770 K the desorption of Cu started to reduce the surface concentration of Cu, thus making a reliable estimation of the segregation rate impossible. During the annealings, in addition to the surface segregation of copper, the surface segregation of alloying and impurity elements was observed as well. Moreover, it appeared that some of these constituents compete for available surface sites. For example, it could be concluded that the surface segregation of copper hindered the surface segregation of carbon in the Fe–Si–Al alloys.
Titanium hydride is well known for its stability in air because of formation of thin TiO2 oxide layer on top of TiH2 powder particles. Formation of the oxide layer is directly related to high ...affinity of Ti to oxygen and it can be formed in few seconds also on top of TiH2 particles in low vacuum. On the other hand, thickness of TiO2 layer on the formed TiH2 powder is in the range of 130 nm. Existence of oxide layer on top of powder particles was confirmed with AES, XPS and EDXS cross section line scans. Formation of thin oxide was confirmed also with calculations based on chemical and TG analyses.
Alumina-supported palladium-copper catalysts, which promote liquid-phase nitrate reduction, have been prepared according to different impregnation sequences of γ-Al
2O
3 support and characterized by ...X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES) and temperature-programmed reduction (TPR). Analysis of Pd XPS/XAES spectra reveals that palladium is present on the γ-alumina support in the metallic form. Copper is reduced at lower temperatures in the presence of palladium particles compared to the CuO/γ-Al
2O
3 sample. Due to the low copper content in catalysts (
σ
Cu≈10
14 atoms
cm
−2), the XPS/XEAS spectral features of reduced copper species are quite different from those of bulk copper. As shown by TPR and XPS/XAES data, formation of highly dispersed Pd-Cu bimetallic clusters is suggested. It was discovered by means of TPR analysis that the catalyst preparation in which the γ-alumina support is impregnated first by copper salt, results in higher formation of the Pd-Cu alloy.
PDF
