Electroforming in the Industry 4.0 Era

In the Industry 4.0 Era, big data and automation will require precise knowledge that allows one to control, monitor and predict a process. Electroforming, which is the fabrication of free-standing components using electrodeposition, is rapidly gaining acceptance as a sustainable additive manufacturing technology. However, current knowledge of electroforming is based on empirical data, and academic engagement in this area has been limited. This article throws light on some of the complex issues surrounding the electrochemical and chemical behaviour during electroforming, which are yet unresolved. The differences between cathodic reactions in sulfamates and sulfates, ambiguities related to the role of boric acid and paucity of data on anode reactions are highlighted.     

Electrical properties of lithiated boron oxide fast-ion conducting glasses

Lithiated boron oxide glasses of the family xLi₂O-B₂O₃, with x ranging from 1.0 to 4.5, were prepared by melting at high temperatures and shaped in the form of slabs. The glasses’ properties were evaluated by Complex Impedance Spectroscopy and Scanning Electron Microscopy techniques. The variation of lithium-ion conductivity at room temperature as a function of the glasses’ lithium content is found to exhibit a maximum at a molar ratio of x=3.5. This maximum in the ionic conductivity is correlated to the formation of crystalline regions in the vitreous structure of the material as the lithium concentration is increased. Paper presented at the 9th EuroConference on Ionics, Ixia, Rhodes, Greece, Sept. 15–21, 2002.     

Evaluation of pozzolanic activity of natural and artificial pozzolans by thermal analysis

In this research, the pozzolanic activity of natural and artificial pozzolan used for preparation of restoration mortars was evaluated. For this purpose, several pastes were prepared, by mixing two artificial pozzolans and a natural one with commercial hydrated lime, in different ratios. The pastes were cured in standard conditions (RH = 98%, T = 25 °C). The pozzolanic activity was evaluated by using simultaneous differential thermal and thermogravimetric analysis (DTA/TG) after curing for 3, 7, 14, 28 days. The obtained results revealed that the various lime/pozzolan pastes displayed different reaction kinetics and therefore the various pozzolans present different reactivity, in proportion to its mineralogical, physical and chemical characteristics.     

Evaluation of solid and submerged fermentations for the production of cyclodextrin glycosyltransferase by Paenibacillus campinasensis H69-3 and characterization of crude enzyme

Cyclodextrin glycosyltransferase (CGTase) is an enzyme that produces cyclodextrins from starch by an intramolecular transglycosylation reaction. Cyclodextrins have been shown to have a number of applications in the food, cosmetic, pharmaceutical, and chemical industries. In the current study, the production of CGTase by Paenibacillus campinasensis strain H69-3 was examined in submerged and solid-state fermentations. P. campinasensis strain H69-3 was isolated from the soil, which grows at 45°C, and is a Gramvariable bacterium. Different substrate sources such as wheat bran, soybean bran, soybean extract, cassava solid residue, cassava starch, corn starch, and other combinations were used in the enzyme production. CGTase activity was highest in submerged fermentations with the greatest production observed at 48–72 h. The physical and chemical properties of CGTase were determined from the crude enzyme produced from submerged fermentations. The optimum temperature was found to be 70–75°C, and the activity was stable at 55°C for 1 h. The enzyme displayed two optimum pH values, 5.5 and 9.0 and was found to be stable between a pH of 4.5 and 11.0.     

Ruthenium(III) ion complexes with nucleotides

Summary Complexes of adenosine-5-monophosphate (5-AMP), guanosine-5-monophosphate (5-GMP), inosine-5-monophosphate (5-IMP) and cytidine-5-monophosphate (5-CMP) with ruthenium trichloride have been prepared and studied by i.r. spectroscopy, diffuse reflectance spectra and magnetochemical measurements.All complexes are probably polymeric as indicated by their insolubility in polar solvents.The i.r. spectra suggest that the ruthenium(III) ion interacts with the ligands through N(7) of the purine mononucleotides and through N(3) of the pyrimidine mononucleotide from one side and with the phosphate group of another mononucleotide molecule from another side. The formation of hydrogen bonds reinforces the interaction.The complexes have normal magnetic moments close to the spin-only value. The electronic spectra confirm their octahedral structure.     

Single-drop liquid-phase microextraction for the determination of hypericin, pseudohypericin and hyperforin in biological fluids by high performance liquid chromatography

The analysis of hypericin, pseudohypericin (collectively called in this study hypericins) and hyperforin in biological fluids is reported using single-drop liquid-phase microextraction in conjunction with HPLC-UV-fluorescence detection. A new option for analysis of the active principle constituents in biological samples is proposed, reducing the steps required prior to analysis. There are several parameters which determine the mass transfer such as the extraction solvent, drop and sample volumes, extraction time and temperature, pH and ionic strength, stirring rate and depth of needle tip in the bulk solution. These parameters were chosen to optimize the performance in the current study. The method was validated with respect to precision, accuracy and specificity. The intra-day precision values were below 2.3% for the high concentration level of control samples and 6.2% for the low level. The respective inter-day precision values were calculated to be below 4.4 and 7.1%, respectively, for the two concentration levels. Accuracy of the method, calculated as relative error, ranged from -2.6 to 7.0%. It was demonstrated that as long as the extraction procedure is consistently applied, quantitative analysis is performed accurately and reproducibly in human urine and plasma samples. Limits of quantitation (LOQs) in urine were calculated to be 3, 6 and 12 ng/ml for pseudohypericin, hypericin and hyperforin, respectively. Slightly higher limits were measured in plasma, i.e. 5, 12 and 20 ng/ml, for the respective analytes.     

Bijections between generalized Catalan families of types A and C

Motivated by the relation ${\mathsf{N}}^m\left(C_n\right)=(mn+1){\mathsf{N}}^m\left(A_{n?1}\right)$, holding for the $m$-generalized Catalan numbers of type $A$ and $C$, the connection between dominant regions of the $m$-Shi arrangement of type $A_{n?1}$ and $C_n$ is investigated. More precisely, it is explicitly shown how $mn+1$ copies of the set of dominant regions of the $m$-Shi arrangement of type $A_{n?1}$, biject onto the set of type $C_n$ such regions. This is achieved by exploiting two different viewpoints of the representative alcove of each region: the Shi tableau and the abacus diagram. In the same line of thought, a bijection between $mn+1$ copies of the set of $m$-Dyck paths of height $n$ and the set of $N?E$ lattice paths inside an $n\times mn$ rectangle is provided.     

Flexible working arrangements in context: An empirical investigation through self-organizing maps

This is one of the first studies to utilize Kohonen’s self-organizing maps on flexible work arrangements (FWAs), employee turnover and absenteeism within different national contexts and an array of organizational factors. While the majority of FWAs did not reduce significantly employee turnover or absenteeism, country and industry were significant contextual variables in FWA use: we deciphered six main country regions, where service and manufacturing organizations were important to FWA preferences. We found a curvilinear relationship between turnover and shift-work among manufacturing firms regardless of country: turnover decreases at low levels and increases at high levels of shift-work. We also found strong positive relationships between weekend work and turnover among manufacturing firms regardless of country and firms in the region comprising of Germany, Austria, Sweden, Finland, Denmark, Czech Republic and Belgium. Finally, we found consistently high concentration of organizations with low absenteeism throughout certain industries and countries: noteworthy are service organizations in the Netherlands and manufacturing organizations in Australia. The results demonstrate the contextuality of FWA use across countries and industries, and the usefulness of SOMs for research within human resource management.