Feasibility Study of Hydrodynamic Lubrication in Supporting of Rotating Elements of Galvanizing Hardware Submerged in Molten Zinc

Severe wear of sink roll supports in continuous galvanizing lines has been a cause for concern for some years. This wear, which affects the quality of the coating and downtime costs, is a result of a corrosive environment and highly loaded surface contact.

This paper presents results from a feasibility study to use journal bearings lubricated with molten zinc to separate the interacting surfaces. Analytical and experimental investigations were aimed at identifying the load capacity of sink roll bearings when operating in the hydrodynamic regime, as well as the effect of the molten zinc bath environment on bearing performance. This environment includes chemical zinc attack and the presence of inter-metallic particles in the bath.

The study indicates that it is difficult to achieve hydrodynamic bearing operation for the entire range of operating conditions. It also shows that, when selecting materials for journal bearings support to the rotating elements submerged in molten zinc baths, possible contact of the bearing surfaces as well as chemical inertness and resistance to the hard intermetallic particles do need to be addressed.     

Content of amino acids and the quality of protein in Brussels sprouts,both raw and prepared for consumption

The aim of the investigation was to evaluate the content of amino acids and the quality of protein in Brussels sprouts. The investigation included the raw material, cooked sample and two types of frozen product stored at ?20 °C for 12 months and then prepared for consumption. The frozen products investigated were obtained using the traditional method (blanching before freezing) and the modified method (cooking before freezing, then defrosting and heating in microwave oven after refrigerated storage) of the ready-to-eat type. Brussels sprouts, both fresh and prepared for consumption, were a good source of protein and amino acids. Proline and glutamic acid were dominating; leucine and tyrosine with phenylalanine were limiting amino acids. The product obtained by modified method contained 16% less amino acids in 16 g N than the raw material and 14% less than the raw material after cooking, and also 10% lower than that of the traditionally obtained product.     

Effect of the type and concentration of lubricating additives on the antiwear and extreme pressure properties and rolling fatigue life of a four‐ball tribosystem

Tests were performed on two different four‐ball testers. The first was used to determine antiwear (AW) and extreme pressure (EP) properties at sliding friction. The second was used to assess the surface fatigue (pitting) life at rolling movement. Lubricating oils of various chemical compositions were tested. A base mineral oil was blended with two different commercial packages of lubricating additives of AW and EP types. The AW additives contained ZDDP and were blended with the base oil at 0.2 and 3wt %. The EP additives were organic compounds of sulphur and phosphorus, blended with the base oil at 1 and 10wt %. It is shown that AW additives not only improve AW and EP properties but also — at 0.2% — are beneficial for the fatigue life. An increase in the concentration of AW additives leads to an improvement of AW and EP properties but — for one of the packages — reduces the fatigue life. EP additives — at 1% concentration — significantly improve EP properties, and to a lesser extent AW properties. Such a concentration of EP additives has no influence on the fatigue life. An increase in the concentration of EP additives leads to a further improvement of EP and AW properties. However, this is accompanied by a considerable decrease in the fatigue life. By using a scanning electron microscope and energy dispersive spectrometer for analysis of the worn surface, mechanisms of action of various lubricating additives under different friction conditions were identified. Copyright © 2006 John Wiley & Sons, Ltd.     

Neutrophil Count as Atrioventricular Block (AVB) Predictor following Pediatric Heart Surgery

Neutrophils play a significant role in immune and inflammatory reactions. The preoperative inflammatory activation may have a detrimental effect on postoperative outcomes. The aim of the study was to investigate the relation between preoperative hematological indices on postoperative complications’ risk in pediatric cardiac congenital surgery. The retrospective single center analysis included 93 pediatric patients (48 (65%) males and 45 (35%) females), mean age of 7 (3–30) months referred for cardiac surgery in cardiopulmonary bypass due to functional single ventricle disease (26 procedures), shunts lesions (40 procedures) and cyanotic disease (27 procedures). Among simple hematological indices, the receiver-operating-characteristic curve showed that a neutrophil count below 2.59 K/uL was found as an optimal cut-off point for predicting postoperative atrioventricular block following pediatric cardiac surgery (AUC = 0.845, p < 0.0001) yielding a sensitivity of 100% and a specificity of 65.62%. Preoperative values of neutrophil count below 2.59 K/uL in whole blood analysis can be regarded as a predictive factor (AUC = 0.845, p < 0.0001) for postoperative atrioventricular block in pediatric cardiac surgery.     

SARS-CoV-2 Altered Hemorheological and Hematological Parameters during One-Month Observation Period in Critically Ill COVID-19 Patients

Hematological and hemorheological parameters are known to be altered in COVID-19; however, the value of combined monitoring in order to deduce disease severity is only scarcely examined. A total of 44 acute SARS-CoV-2-infected patients (aCOV) and 44 age-matched healthy controls (Con) were included. Blood of aCOV was sampled at admission (T0), and at day 2 (T2), day 5 (T5), day 10 (T10), and day 30 (T30) while blood of Con was only sampled once. Inter- and intra-group differences were calculated for hematological and hemorheological parameters. Except for mean cellular volume and mean cellular hemoglobin, all blood cell parameters were significantly different between aCOV and Con. During the acute disease state (T0–T5), hematological and hemorheological parameters were highly altered in aCOV; in particular, anemic conditions and increased immune cell response/inflammation, oxidative/nitrosative stress, decreased deformability, as well as increased aggregation, were observed. During treatment and convalescence until T30, almost all abnormal values of aCOV improved towards Con values. During the acute state of the COVID-19 disease, the hematological, as well as the hemorheological system, show fast and potentially pathological changes that might contribute to the progression of the disease, but changes appear to be largely reversible after four weeks. Measuring RBC deformability and aggregation, as well as oxidative stress induction, may be helpful in monitoring critically ill COVID-19 patients.     

Spectroscopic Characterization and Biological Activity of Hesperetin Schiff Bases and Their Cu(II) Complexes

The three Schiff base ligands, derivatives of hesperetin, HHSB (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]isonicotinohydrazide), HIN (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]benzhydrazide) and HTSC (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]thiosemicarbazide) and their copper complexes, CuHHSB, CuHIN, and CuHTSC were designed, synthesized and analyzed in terms of their spectral characterization and the genotoxic activity. Their structures were established using several methods: elemental analysis, FT-IR, UV-Vis, EPR, and ESI-MS. Spectral data showed that in the acetate complexes the tested Schiff bases act as neutral tridentate ligand coordinating to the copper ion through two oxygen (or oxygen and sulphur) donor atoms and a nitrogen donor atom. EPR measurements indicate that in solution the complexes keep their structures with the ligands remaining bound to copper(II) in a tridentate fashion with (O^–, N, O_ket) or (O^–, N, S) donor set. The genotoxic activity of the compounds was tested against model tumour (HeLa and Caco-2) and normal (LLC-PK1) cell lines. In HeLa cells the genotoxicity for all tested compounds was noticed, for HHSB and CuHHSB was the highest, for HTSC and CuHTSC–the lowest. Generally, Cu complexes displayed lower genotoxicity to HeLa cells than ligands. In the case of Caco-2 cell line HHSB and HTSC induced the strongest breaks to DNA. On the other side, CuHHSB and CuHTSC induced the highest DNA damage against LLC-PK1.     

Impact of the addition of dolomite to cream-firing clays on the technological and color properties of sintered ceramics

Sintered ceramics, represented by ceramic tiles or clinker bricks, are widely used in the building materials industry due to their technological properties and visual qualities. The topic of color changing of ceramic materials from cream-firing clays with the use of mineral additives has not been addressed to date. The aim of the paper was to investigate the effect of granulation of dolomite additives to ceramic masses based on cream-firing Borkowice clay on the color and properties of fired ceramic materials. The paper proposes that grain size of mineral additive affects the color of sintered ceramics. In order to confirm this hypothesis, a number of experiments were performed, consisting of determination of the color and technological properties of ceramic materials. The conducted tests showed that the color and technological properties of sintered ceramics are influenced by the grain size of the additives used.     

Modular Coiled Flow Inverter with Narrow Residence Time Distribution for Process Development and Production

The ideal plug flow reactor is a common model with narrow residence time distribution in reaction engineering. This contribution explains a design strategy of a coiled flow inverter (CFI) with narrow residence time and flexible adjustable process conditions. The design space diagram illustrates the design limits of inner diameter and coil diameter on the base of dimensionless numbers. Standard coil tube diameters allow for rational design of a limited number of devices. The reactor performance diagram enables the facile scale‐up and adaption of new process conditions with the CFI with economic boundary conditions.     

Measurement of management efforts with respect to integration of quality,safety, and ergonomics issues in manufacturing industry

The main objective of this study was to identify critical factors that measure management efforts with regard to quality, safety, and ergonomics issues for their simultaneous improvement. Eleven identified management activity areas have been synthesized from the literature as the most important areas that meet all stakeholders' needs. Factors were then developed to measure the efficiency of these activities through a questionnaire. The overall response rate of the survey questionnaire was 47%. The reliability coefficients ranging from 0.73 to 0.85 indicated that some scales or management activity areas are more reliable in measuring potential for improvements in terms of quality, ergonomics, safety, and efficiency. The proposed instrument for quantifying management efforts with respect to simultaneous improvements in the areas of quality, ergonomics, and safety was found to be valid and reliable. © 2005 Wiley Periodicals, Inc. Hum Factors Man 15: 213–232, 2005.