Electrophilic chlorination of methane over superacidic sulfated zirconia

Catalytic chlorination of methane was studied over SO ₄ ^2– /ZrO₂, Pt/SO ₄ ^2– /ZrO₂, and Fe/Mn/SO ₄ ^2– /ZrO₂ solid superacid catalysts. The reactions were carried out in a continuous flow reactor under atmospheric pressure, at temperatures below 240°C, with a gaseous hourly space velocity of 1000 ml/g h and a methane to chlorine ratio of 4 to 1. At 200°C with 30% chlorine converted the selectivity in methyl chloride exceeds 90%. At more elevated temperatures, the selectivity decreases but stays above 80% in methyl chloride at 225°C using the sulfated zirconia catalysts. The selectivity can be enhanced by adding platinum to sulfated zirconia catalysts. An iron and manganese-doped catalyst exhibited excellent selectivities at somewhat lower conversions. Methyl chloride is obtained at 235°C in selectivities greater than 85%. No chloroform or carbon tetrachloride is formed. The electrophilic insertion involves electron-deficient metal-coordinated chlorine into the methane C-H bond.Catalysis by solid superacids, 29. For part 28 see ref. [14].     

SEM and EDS investigation of a pyrolytic carbon covered C/C composite maxillofacial implant retrieved from the human body after 8 years

The long term effect of the human body on a pyrolytic carbon covered C/C composite maxillofacial implant (CarBulat^Tm) was investigated by comparing the structure, the surface morphology and composition of an implant retrieved after 8 years to a sterilized, but not implanted one. Although the thickness of the carbon fibres constituting the implants did not change during the 8 year period, the surface of the implant retrieved was covered with a thin surface layer not present on the unimplanted implant. The composition of this layer is identical to the composition of the underlying carbon fibres. Calcium can only be detected on the surface as a trace element implying that the new layer is not formed by bone tissue. Residual soft tissue penetrating the bulk material between the carbon fibre bunches was found on the retrieved implant indicating the importance of the surface morphology in tissue growth and adhering to implants.     

Semitransparent monocrystalline solar cells manufactured by laser cutting and anisotropic etching

This paper presents two possible technologies used to manufacture semitransparent monocrystalline building integrated solar cells: laser cutting and anisotropic etching. Nd:YAG 1,064 nm laser cut sidewalls are rough and contain molten residues, resulting in shunts across the through-holes confirmed by I–V characteristic measurement and reverse bias measurement results. Tetramethylammonium hydroxide etched edges are uniform with smooth sidewalls. Carrier lifetime and Kelvin probe measurements reveal the flaws occurring in the two technologies.     

Orthodontic treatment and temporomandibular disorders: is there a relationship? Part 1: Clinical studies

Patient perceptions of the quality of services provided is a key factor (along with cost effectiveness) in determining a health care organization's competitive advantage and survival. This article examines the advantages, disadvantages, and problems associated with nine different methods of measuring patient satisfaction with service quality. The appropriateness of each of these techniques under different organizational conditions is also discussed. The article concludes with guidelines for measurement of patient satisfaction and implementation of managerial follow-up.     

CFD models in the development of electrical waste recycling technologies

Nowadays electrical waste (EW) recycling has become a practical way to provide raw material for new devices. Computer parts such as memory, motherboard or other parts contain large amount of metals from which the recovery of precious metals and copper represents the highest economical potential. With a proper chemical treatment these metals can be efficiently extracted and separated from the actual waste. For this task a specially designed leaching reactor, equipped with a perforated rotating drum, was used. This work is aimed at investigating if computational fluid dynamics (CFD) tools can be efficiently applied to model the chemical reactor used to dissolve the metals from the EW. First a hybrid CFD-compartment approach was developed to describe the dissolution process in the leaching reactor while the CFD models were used to model the hydrodynamics of the process. Based on the detailed model containing momentum and component mass balance the developed simulator could be used to enhance the performance of the existing reactor system. For the modelling studies COMSOL Multiphysics was used as CFD software.     

Cardioprotection during heart ischemia-reperfusion

Oxygen reactive species play a significant role in reperfusion tissue damages. In this study we aimed to investigate the mechanisms of injury regarding changes of neutrophil function. In our experiments the left descending coronary artery (LAD) was ligated in Beagle dogs for 1 hour followed by one hour reperfusion. Animals were divided into two groups: Group I. dogs (n = 10) served as control: Group II. the animals (n = 10) were treated by cardioprotective drug Bisaramil. Peripheral blood samples were taken for neutrophil isolation before operation and subsequent reperfusion (5 min, 1 hour). The stimulated superoxide radical generating capacity of polymorphonuclear leukocytes (PMN) was measured. The lipid peroxidation (MDA), amount of reduced glutathione (GSH) and activity of superoxide dismutase (SOD) were measured in non-ischemic and ischemic parts of left ventricle. There was no significant changes either in control or in treated animals in respect to changes of neutrophil radical production after one hour LAD ligature, however there was a significant discrepancy (p < 0.001) between control and treated animals following a 1 hour reperfusion. The values of MDA in the ischemic-area increased characteristically in the Group I. parallel with decrease of scavenger GSH and SOD. In contrast in Group II., where depleted PMN radical production was observed endogenous scavengers were preserved on a higher level. In summary we can conclude that diminished superoxide radical production of circulating neutrophils during reperfusion has beneficial effects on tissue injury caused especially by free radicals.     

Interrelation between the climate-related sustainability and the financial reporting disclosures of the European automotive industry

The financial reports of the automotive companies' are measured in a standardized manner; therefore, they are transparent and comparable to each other, but this is not valid for the sustainability reports and it is not possible to compare their sustainability performances. Standard-setting organizations are currently searching for better reporting procedures. This study aims to investigate the connection between sustainability and financial reports for the most dominant European car manufacturers. It reviews the traceability of the sustainability elements back to the financial statements, which helps transparency, comparability, and impact measurement of the disclosed items and issues. This investigation allowed us to additionally review whether these companies are targeting to disclose the most harmful pollution impacts, or only focus to disclose the required obligatory items. Given the financial and sustainability reports magnitude manual testing would not provide complete and proper coverage, therefore we utilized an automated and AI-assisted content analysis with natural language processing. In this new review method, the sustainable elements of the textual reports were automatically retrieved following the 5-stage model of Landrum & Ohsowski (2018). The study highlights the lack of true sustainability information content of reports and the potential discrepancies and connections between the financial and the sustainability reports. Findings concluded that sustainability disclosures at the reviewed companies from several aspects could be improved and quantified, traced back to the financial disclosures, and to be comparable to each other if they apply a similar review method.

Graphic abstract