Polished Samples Research Articles

Analisa Karakterisasi Baja Paduan As-Cast-Fe-Cr-Mn-Mo Dengan Komposisi Nikel Terhadap Sifat Mekanik Dan Struktur Mikro Hasil Uji Balistik

Lateritic steel is a low-nickel steel with a nickel content of 1-4.5 percent. Steel with a high nickel percentage has better qualities like high strength, corrosion resistance, and weldability. This material is commonly used in crushers and grinding machines. This material can also be utilized as an armor material. A study was undertaken to investigate the ability of laterite steel to be employed as armor material by characteristic testing (impact test and hardness test) and microstructure (metallography) of laterite steel. ASTM standards must be followed in the preparation of all samples. The impact test was performed on 9 samples from 3 specimens, with each sample being placed on an anvil and pounded with a pendulum that the average values of samples A, B, and D were 11 J, 9 J, and 12 J, respectively. The fractures were granular, indicating that the material is extremely fragile. The hardness test was then performed using the Vickers method with a 5 Kgf load. The polished sample is placed immediately on a vise, and then a diamond-shaped indenter is attached; the hardness test value is determined by the size of the trace of the indenter, with the average values of samples A, B, and D being 292.63 HVN, 310.47 HVN, and 464.87 HVN, respectively. Microstructure measurements revealed that sample A formed ferrite perlite, sample B formed lower bainite, and sample D formed martensite phase.

Birefringent phase masks for laser beams shaping during laser material processing at imaging plane

We present phase masks (PMs) made from birefringent CaCO3 crystal plates to create laser beams at an imaging plane with given shapes and intensity distributions close to flat-top distributions. The principle of PMs is based on creating the phase shift of π or 2π (depending on the initial plate thickness) in linearly polarized radiation passing through etched areas with given shapes. The phase shift in these areas is converted into the intensity distribution at an analyzer output, which can be projected with a demagnification by a high-quality lens into its imaging plane aligned with a microprocessing plane or target. In this research, we provide theoretical discussion of choosing PM configurations. PMs with the square and quadrating square shapes (such configurations are in demand in laser microprocessing and molecular optics) were fabricated by laser-induced microplasma and successfully tested in the experimental setup with a pulsed laser (with a wavelength of 1.06 μm and pulse duration of 120 ns). PMs were also used in this experimental setup for laser ablation of polished steel samples. Contours of footprints on samples were well matched with formed beam shapes.

Effect of substrate surface finish and particle velocity on fatigue performance of cold spray coated A6061 aluminum alloy

Cold spray coatings made with powder of the same material as the substrate can be used to improve fatigue performance and/or to repair damaged parts. The effects of substrate surface finish and particle impact velocity on the bond strength and fatigue performance of Al-6061-T6 substrates coated with Al-6061 powder by using high pressure cold spray (CS) were investigated. To evaluate the effect of particle velocity, coatings were prepared by using both nitrogen (N2) and helium (He) as carrier gases. A new method for substrate surface preparation was introduced by low angle spraying (LAS) with the same powder prior to coating. The bond bar specimens in polished, semi-polished, grit-blasted (GB) and low angle sprayed (LAS) conditions were coated and tested for bonding strength. The microstructural characteristics and microhardness profiles of the coated samples were also evaluated. Fatigue tests on uncoated and coated samples were conducted under fully-reversed axial loading in load-controlled condition. The failure mechanism was identified by evaluating the fracture surfaces using scanning electron microscopy. The results showed that both bonding strength and fatigue performance of the coated specimens prepared by using He-gas were significantly higher than those prepared by using N2. Among the N2-sprayed coatings, the bonding strength of on LAS substrates were significantly higher than that of the other surface conditions, and the bonding strength of coatings on GB substrates was superior to that of polished and semi-polished samples. However, the fatigue performance of LAS-coated samples was inferior compared to uncoated samples due to cracks initiating in the coating and propagating into the substrate. The fatigue behavior of GB-coated specimens was similar to the uncoated samples due to delamination of the coating which resulted in stopping the cracks that initiated in the coating.

Electrochemical characterization and degradation of carbon fibre reinforced polymer in quiescent near neutral chloride media

In a quest for a better understanding of the mechanism and contribution(s) of fresh (“un-degraded”) and degraded CFRP surfaces to galvanic corrosion of coupled metals in multi-material assemblies the electrochemical behaviour of CFRP in quiescent 50 mM NaCl was studied using electrochemical techniques. Tests using ferricyanide/ferrocyanide redox couple revealed a quasi-reversible behaviour. Under cathodic polarization, CFRP is active electrochemically evidenced by the increase in pH (to pH ≥ 10). Galvanic current densities and potentials for Al-CFRP couple comprised of freshly polished CFRP sample ranged from 15–25 µA cm−2 and ≈−660 to −850 mVSCE respectively, while the corresponding parameter for Al-CFRP couple comprised of degraded CFRP were in the range 10–25 µA cm−2 and ≈−670 to −900 mVSCE. Contrary to expectations, CFRP prior exposure to degradative high pH media before galvanic coupling did not result in an increase in the intensity of galvanic corrosion of the coupled metal.

CRANIOLOGY AND SEX-AGE CHARACTERISTICS OF THE UZHHOROD CASTLE CHURCH BURIALS OF THE SECOND HALF OF 14TH – 17TH CENTURIES

The remains of 130 burials from the territory of the destroyed castle church in Uzhhorod were collected and investigated for two years (2018–2019). These are 71 ground burials outside the crypt, one preserved burial inside the crypt, and 58 skulls (or fragments thereof) from demolished crypt burials that are morphologically indistinguishable from preserved outside the crypt burials. That served the reason to combine them into one series. Chronologically, all the anthropological material belongs to the second half of the 14th – 17th century. This article aims to characterize the anthropological structure of people buried in the church on the territory of Uzhhorod Castle, namely the sex-age aspect and features of their craniological type. The article aims to introduce new craniological data into the scientific circulation and identify the main directions of ethnic connections of the studied group from Uzhhorod. The paper’s objective is to determine the distances between individual synchronic and diachronic series with the help of multidimensional canonical and cluster analysis and to find out the place of the Uzhhorod sample in the system of craniological types of Central, Eastern, and Northern Europe (except the Caucasus) and phenogeographical anthropological zones of Ukraine. Computer software designed by B. Kozintsev and O. Kozintsev in 1991 has been used in the research. Fourteen craniometric traits defined by R. Martin have been involved in the analysis. It is established that 118 out of 130 burials belong to adults. It is defined that 86 (72.88%) of them are male, and 32 (27.12%) are female. The average age of death in adults is about 38 years (it varies from 33.5 to 42.5 years). The average age of death of the male part of the sample is about 40 years (within 30–50 years), and of the female part – about 32.5 years (within 25–40 years). For the first time, the male and female series from Uzhhorod was created. In general, 90 skulls (67 male and 23 female) were suitable for craniometry, not counting children’s ones. It has been found out that males and females buried in the church of Uzhhorod Castle belong to the same craniological type. The male sample is moderately brachycranic. On average, it is presented with a wide with a strongly profiled at the level of the orbits and alveolar ridge face belonging to the orthognathic type. The orbits are wide. The nose is medium, and the nasal protrusion angle is moderate. The nasal bridge is high. The female sample is, on average brachycranic. The face is moderately wide with small height, strongly profiled at the level of orbits belonging to the orthognathic type. The orbits have small widths and heights. The nasal bridge is high. The nasal projection angle is very large. According to two anthropological methods (craniometry and cranioscopy), the examined group is mixed, demonstrating certain western, northern, and predominant southern traits. When comparing the male sample group to synchronic and diachronic series and samples from the territory of Central, Eastern, and Northern Europe by the method of multidimensional canonical and cluster analysis, its partial similarity to the Polish sample of the skulls from the Church of Mary Magdalena (Wroclaw), the Volyn series from the village of Ratniv, and to a lesser extent – to the Baltic group of the 14th – 17th century from Martinsala (Latvia) has been determined. The same comparison of the female group has revealed its certain similarity to the Kyiv sample from Podil (Yurkivska Street) according to the results of the multidimensional canonical analysis. According to cranioscopy data, the similarity of the studied group (male and female) to the Lviv and Berestechko series (north-eastern direction of connections) has been revealed at this stage.

Psychometric validation of the polish version of the emotional style questionnaire.

In three studies, we document the validity of the Polish version of the Emotional Style Questionnaire (ESQ)—a 24-item self-report measure that captures how people vary across six dimensions that make up a healthy emotional life. Study 1 provides support for the proposed factorial structure of the Polish version of the scale and gender measurement invariance, demonstrates the similarity of the Polish and English versions of the scale, and reveals the excellent test-retest reliability of the scale across an interval of two months. Study 2 confirms the adequacy of the factorial structure in another sample, shows that the construct validity for each of the six subscales is similar to that of the original scale, and documents the age measurement invariance of the scale. Finally, in Study 3, we investigate measurement invariance across Polish and American samples and demonstrate that Poles are characterized by lower scores on healthy emotionality and its dimensions compared to Americans. We conclude that the Polish version of the ESQ is a psychometrically valid and easily implementable measurement tool that can be applied in research settings to measure healthy emotionality and its components.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12144-022-03323-4.

Anxiety towards COVID-19, Fear of Negative Appearance, Healthy Lifestyle, and Their Relationship with Well-Being during the Pandemic: A Cross-Cultural Study between Indonesia and Poland.

The COVID-19 pandemic has led to massive changes in almost all aspects of human life, including emotional states such as anxiety and fear, perspectives about healthy lifestyles, and psychological outcomes. This study aimed to disentangle the mechanisms that underlie the relationships of anxiety towards COVID-19 and fear of negative appearance with well-being, we also investigated the effects of cultural variations on levels of anxiety, fear of negative appearance, healthy lifestyles, and well-being. A total of 881 Indonesians (n = 172) and Poles (n = 709) participated in this study. Participants completed self-report measures of psychological well-being, anxiety, fear of negative appearance, compulsive exercise, and eating disorders. Multigroup structural equation modelling (SEM) was used. The results showed no statistically meaningful relationship between anxiety towards COVID-19 and well-being. However, it was found that, in the Polish sample, compulsive exercise and eating disorders mediated the relationship between fear of negative appearance and well-being. Cultural differences were also found in the mean scores of all examined constructs, with eating disorders being an exception. Therefore, this study highlights cultural aspects that determine emotional states, healthy lifestyles, and well-being.

Micromorphology, Microstructure, and Wear Behavior of AISI 1045 Steels Irregular Texture Fabricated by Ultrasonic Strengthening Grinding Process

In this study, the tribological properties of three AISI 1045 steel samples were investigated. Two samples were treated with ultrasonic shot peening (USP) and ultrasonic strengthening grinding process (USGP), respectively, while the other one was only treated with a polishing process. Sample properties, such as surface morphology, roughness, microhardness, elastic modulus, frictional coefficient, and phase structures were analyzed. Results show that the sample treated with USGP had the best tribological properties. It realized the highest surface roughness, microhardness, and elastic modulus. Compared with a polished sample, the roughness of the sample treated with USGP increased by 157%, and the microhardness and elastic modulus improved by 32.8% and 21.3%, respectively. Additionally, USGP provided an average frictional coefficient of 0.4, decreasing approximately 45% compared to polishing. The possible mechanisms of USGP surface texturing were discussed. The findings denote that USGP could be an efficient approach to improve the fatigue life of some mechanical components.

Experimental study of surface roughness on improving the tribological performance of sealing pairs in magnetorheological damper

Comprehension of the tribological behavior of magnetorheological fluid (MRF) is crucial in many fields, particularly those related to seal wear. The sealing conditions are more complex than traditional media due to composition and rheological characteristics of MRF. The sealing pairs are prone to wear failure when in contact with magnetic particles. To this end, the paper focuses on the influence of surface roughness on MRF tribological properties with and without magnetic field. The whole experiment is carried out by a self-developed device to reproduce the wear evolution between the sealing pairs for magnetorheological damper. Experimental results show that higher surface roughness exhibits lower friction coefficient and better friction performance under MRF, especially in the absence of magnetic field. This is in stark contrast to the best wear resistance exhibited by polished samples under methyl silicone oil, a carrier fluid of MRF. This means that the effective coupling between surface roughness and iron particles helps to improve the friction and wear performance of sealing pairs. On this basis, the optimum surface roughness values of metal pin under MRF are obtained. Subsequently, the effect of pin surface morphology on the dynamics of iron particles are confirmed through the analysis of scanning electron microscopy images. It is further demonstrated that wear mechanism varies with surface roughness, that is, as the roughness increases, from sliding to mixing, and finally to rolling. Consequently, this research is of great significance for improving the wear resistance of sealing pairs under MRF.

Gender and age differences in forgivingness in Italian and Polish samples

This study explores gender and age differences in forgivingness using the crosscultural and stress-and-coping perspective. Polish and Italian versions of the Heartland Forgiveness scale (HFS) were used. The sample consisted of 1957 individuals aged 18–80 (61% females and 39% males). A 3-way between groups ANOVA was used to examine the main effects and interactions of country, age and gender as they relate to total HFS score. Post-hoc analyses were performed where appropriate. The results revealed that Polish and Italian respondents did not differ in the level of the general tendency to forgive. Gender differences in trait forgiveness were reported in whole sample and in Italian subsample, showing males to be more forgiving than females. Further, our results for all study participants, in Polish subsample and among Italian males showed that older adults were more forgiving than young respondents, which is consistent with the previous findings showing an increase in forgivingness with age.

Zirconia-based abradable coatings fabricated on single-crystal superalloy: Microstructure, residual stress and mechanical properties

Thermal sprayed ZrO2-based abradable coatings have shown great advantages in blade/shroud clearance control systems of aero-engine turbine components due to their good high-temperature stability and abradability. Dysprosia-stabilized-zirconia (DySZ) based Abradable Coating were deposited on the Ni-based single-crystal superalloy via atmospheric plasma spraying technique. Microstructure evolution behaviors of the ZrO2-based abradable coating and the substrate were examined after 1100 ℃ thermal cycling. Besides, variation of the residual stress of the top layer was measured by Raman spectroscopy. Nanoindentation tests were conducted on the polished cross-section samples to evaluate Young's modulus and hardness evolution behavior. Results indicated that the DySZ top layer exhibits superior phase stability and good thermal shock resistance during thermal cycling. Thermally Grown Oxide (TGO) layer, Inter-Diffusion Zone (IDZ), and Second Reaction Zone (SRZ) was detected with the prolongation of the heat treatment time. Correlation between the microstructure and residual stress, hardness, Young's modulus of the coating was discussed. This study aims to further understand the relationship between the coating evolution behavior and the service time.

The initial Polish adaptation of the Mind Wandering Questionnaire: translation and verification of the scale internal consistency

Abstract Introduction: The aim of the current study was to present the results of the first step of the Mind Wandering Questionnaire (MWQ) adaptation to the Polish sample. The adaptation involved performing translation of the scale, verification of the translated items’ accessibility and the analysis of the internal consistency. Material and methods: MWQ in original form is a single-factor short self-assessing questionnaire composed of five items with a 6-point Likert-type answering scale. The translation of items was performed by a professional language expert according to psychometric rules. The research group included 70 healthy young adults (students), aged 21.53, an equal number of males and females. Results: The adapted questionnaire exhibited a single-factorial structure and satisfactory parameters of internal consistency: Cronbach’s alpha was 0.78, all individual items were significantly correlated with MWQ total score, and the mean value of correlation reached 0.74. The mean value of the adopted MWQ total score reached 15.84 (SD = 4.11). The study showing the initial step of the questionnaire adaptation revealed that the scale in the Polish version has an internal structure comparable with the original one, and its internal consistency exhibited good parameters. Conclusions: In the next steps of the scale full adaptation, a convergent validity assessment should be carried out together with correlations with other scales assessing psychological constructs and dimensions of individual differences associated with Mind Wandering, such as neuroticism and impulsiveness.

Fast imaging of laser ablation of cerium: Dependence of plasma plume dynamics and structure on native oxide growth

We have imaged the evolution of plasma following nanosecond pulsed laser ablation of cerium in air with sub-10 ns resolution. We find the ablated plasma plume expansion and shape to be strongly dependent on the time after mechanical polishing of the sample surface. After an initial shock front common to both new and aged samples (velocities up to 16 km s−1), we observe a second front that is relatively localized to the surface vicinity of newly polished samples, but in the case of older samples it moves outward at velocities of up to 4 km s−1. We attribute this behavior to the formation and growth of a native oxide layer on the order of hours after polishing. These results demonstrate that plasma imaging can be used to diagnose the presence of, and evaluate the extent of, thin surface oxides or other compounds that form soon after exposure to some atmosphere. These findings also highlight the need to explicitly consider the presence of such overlayers when modeling laser/metal interaction, when making measurements of vapor phase chemistry, and when analyzing the composition, phase, and morphology of solid particulates formed after the ablation of reactive metals.

Predictors of Compulsive Sexual Behavior Among Treatment-Seeking Women.

BackgroundCompulsive Sexual Behavior Disorder is currently included in the forthcoming eleventh revision of the International Classification of Diseases (ICD-11); however, prior studies have been conducted mostly on heterosexual, White/European male samples.AimTo examine the correlates of compulsive sexual behaviors (CSB) with sociodemographic and sexual history characteristics, as well as predictors of CSB in a sample of treatment-seeking Polish women.MethodsSix hundred seventy-four (674) Polish women aged 18–66 completed an online-based survey.OutcomesPolish adaptation of the Sexual Addiction Screening Test-Revised (SAST-PL) was used to assess the severity of CSB symptoms. Brief Pornography Screen was used to measure problematic pornography use. The bivariate associations between SAST-PL scores and demographic and sexual history characteristics were also examined. A linear regression analysis was performed to identify variables related to the severity of CSB symptoms.ResultsThirty one percent (31.8%) of women in the studied sample reported treatment seeking for CSB in the past. Problematic pornography use was the strongest predictor of CSB symptoms. Higher severity of CSB symptoms were observed among divorced/separated and single women compared to those who were married or in informal relation. Severity of CSB was positively related to the number of sexual partners during the last year, number of dyadic sexual intercourse during the last 7 days, and negatively associated with age of first sexual intercourse.Clinical ImplicationsOur results suggest that CSB is a significant concern among women and more research is needed to identify protective (eg, relationship status) and risk (eg, problematic pornography use, number of past year sexual partners, frequency of past week masturbation) factors associated with CSB symptom severity among treatment-seeking women.Strengths & LimitationsOur study is one of very few investigating predictors of CSB among women. Given the lack of precise estimates of the prevalence, as well as lack of psychometrically validated instruments measuring CSB in women, present findings should not be considered indicative of CSB prevalence among Polish women.ConclusionThe lack of clinical data on women reporting issues with CSB remains an important target for future clinical research exploration.Kowalewska E, Gola M, Lew-Starowicz M, et al. Predictors of Compulsive Sexual Behavior Among Treatment-Seeking Women. Sex Med 2022;10:100525.

Surface Characteristics of High Translucent Multilayered Dental Zirconia Related to Aging.

(1) Background: The purpose of this study was to evaluate the differences in terms of surface characteristics (roughness, topography, microhardness) among layers for multi-layered high translucent and super-high translucent zirconia and the influence of finishing and aging on surface characteristics and microstructure. (2) Methods: Three types of translucent multilayer zirconia were evaluated: STML (4Y-TZP); IPS e.maxZirCAD CEREC/in Lab MT Multi (4Y-TZP + 5Y-TZP); CeramillZolidfx ML (5Y-TZP). Ninety-six plate-shaped samples (32 for a material), 16 mm × 14 mm × 1 mm size, were cut with a precision disc, polished on both sides with sand papers and sintered respecting the manufacturer’s protocol. Half of the specimens (16) were finished by polishing and the other half by glazing and then equally divided into one control group and one group subject to aging by autoclaving (1 h, 134 °C, 0.2 MPa), resulting in four groups of eight samples, for each zirconia. The specimens were evaluated in three areas: cervical, medium, incisal-of each glazed or polished surface, before and after aging. Tests were performed to determine the surface roughness using a profilometer; the surface topography by an atomic force microscope (AFM) and a scanning electron microscope (SEM). Microhardness was recorded using a microhardness tester. Statistical analyses were performed using two-way ANOVA test, unpaired sample t-Test, paired sample t-Test (α = 0.05) and Pearson’s correlation. (3) Results: Before and after autoclaving, for glazed samples significance (p < 0.05) higher surface roughness, respectively lower microhardness in comparison with the polished group was assessed. No significant differences (p > 0.05) were reported between the three areas, on glazed or polished surfaces of a material. Although, after aging an increase in surface roughness was observed both on glazed and polished samples, statistical differences were found for STML (p < 0.05). No significant differences (p> 0.05) concerning microhardness among the same areas, on glazed and polished surfaces, recorded before and after aging, except CeramillZolidfx ML glazed samples. (4) Conclusions: For tested zirconia materials no significant differences among layers were registered regarding surface characteristics. Surface treatment (glazing or polishing) has a significant impact on surface roughness and microhardness. Both before and after aging, the surface roughness values for the glazed samples were higher than for those polished. The super translucent 4Y-TZP material was more affected by aging compared to the super-high translucent 5Y-TZP material. The combined material revealed similarities for each layer corresponding to the microstructure.

Etching of Manganese Aluminum Bronze by Ultrasound in Seawater

Abstract Manganese Aluminum Bronze (MAB), UNS designation C95700, is an alloy widely used for large marine propellers and other components in hydropower units. MAB has a complex microstructure due to precipitation of intermetallic phases as consequence of the cast process or thermal treatments. When investigating the marine corrosion behavior of MAB alloys, it was found that a metallographic etching attack occurred under the effect of ultrasound, similar to that observed with chemical reagents used for high-alloy bronzes. The main aim of this work is to compare the effects of etching on polished metallographic samples by ultrasound in seawater with that obtained with conventional chemical agents. It can be concluded that the effect of ultrasound is able to reveal, with great precision, the microstructure of MAB alloys, without the use of aggressive chemical agents, while the time under the influence of ultrasonic energy allows for fine-tuning the etching effect.

Climate Change Anxiety Assessment: The Psychometric Properties of the Polish Version of the Climate Anxiety Scale.

The Climate Anxiety Scale (CAS) is a 13-item questionnaire for assessing climate anxiety (CA) as a psychological response to climate change. The CAS consists of two subscales, namely, cognitive impairment and functional impairment. This study aimed to validate the Polish version of the CAS. The sample included 603 respondents (344 females, 247 males, and 12 non-binary), aged 18–70 years (M = 25.32, SD = 9.59). Based on the exploratory factor analysis results, we proposed a 3-factor solution (i.e., intrusive symptoms, reflections on CA, and functional impairment), which seems to be theoretically more consistent with the content of the CAS statements. The confirmatory factor analysis showed that the original 2-factor solution and the 3-factor one had a satisfactory and a good fit to the data, respectively, as well as both were invariant across different gender, age, and educational level categories. Despite the fact that the 3-factor solution had the best-fit indices, we recommended to examine the CAS structure in different samples and use the overall CAS score in cross-cultural research. Cognitive and functional impairment subscales were positively correlated with personal experience of climate change, behavioral engagement, environmental identity, and environmental motives, but they were negatively correlated with climate change denial and sense of safety. The CAS subscales were correlated with depressive symptoms, but contrary to expectations, they were not associated with anxiety symptoms and any cognitive coping strategies. The Polish version of the CAS has satisfactory psychometric properties. Overall, we reported low CA levels in the Polish sample. Women and younger people experienced higher CA.

Occurrence and translocation of ustiloxins in rice false smut-occurred paddy fields, Hubei, China

Ustiloxin A (UA) and ustiloxin B (UB), two major mycotoxins produced by the pathogen of rice false smut (RFS) during rice cultivation, have attracted increasing attentions due to their potential health risks. However, limited data are available about their occurrence and fate in paddy fields and contamination profiles in rice. In this study, a field study was performed to investigate the occurrence and translocation of UA and UB in RFS-occurred paddies. For the first time to our knowledge, we reported a ubiquitous occurrence of the two ustiloxins in the paddy water (range: 0.01–3.46 μg/L for UA and <0.02–1.15 μg/L for UB) and brown rice (range: 0.09–154.08 μg/kg for UA and <0.09–23.57 μg/kg for UB). A significant positive correlation was observed between ustiloxin levels in paddy water and brown rice (rs = 0.48–0.79, p < 0.01). The occurrence of ustiloxin uptake in water-rice system was also evidenced by the rice exposure experiment, suggesting paddy water might be an important source for ustiloxin accumulation in rice. These results suggested that the contamination of ustiloxins in rice might occur widely, which was supported by the significantly high detection frequencies of UA (96.6%) and UB (62.4%) in polished rice (149 samples) from Hubei Province, China. The total concentrations of ustiloxins in the polished rice samples collected from Hubei Province ranged from <20.7 ng/kg (LOD) to 55.1 μg/kg (dry weight). Further studies are needed to evaluate the potential risks of ustiloxin exposure in the environment and humans.

Influence of process variables on shoe polish viscosity

Valourisation of non-biodegradable wastes into value added products like shoe polish can indeed be an effective tool for waste management and climate change mitigation. However, having appropriate shoe polish viscosity is important for customer satisfaction as too thick or too thin shoe polish may not result in desired customer satisfaction. The aim of this study was to investigate the effects of process variables (water repellant nature, process temperature, carbon black source and particle size, as well as, composition type and quantity) on shoe polish viscosity. The viscosity values of the various samples of shoe polish produced using carbon black pigments from batteries, pyrolytic rubber tyres, plastic bottle and water sachets wastes were determined. From the results obtained, it could be observed that shoe polish samples that had almost the same value of dynamic viscosity (η = 0.2389) with that of the commercial Kiwi shoe polish included the shoe polish with used vegetable oil as water repellant and the shoe polish with dye sourced from discarded batteries and plastic bottle wastes but with particle sixe of 0.80 mm. On comparison of the viscosity values of other shoe polish samples with that of the Kiwi shoe polish, it was observed that all shoe polish samples evaluated for all the distinctive process variables except temperature had comparable viscosity with that of Kiwi shoe polish. The real difference in viscosities of the shoe polish samples was observed when the process temperature was below 60 °C. This indicates that temperature as a process variable is the main determining factor regarding the viscosity of the shoe polish samples.

Comparison of the Antioxidant Activity of Propolis Samples from Different Geographical Regions.

Propolis composition depends on several factors. The classification of propolis is based on its geographical location, color and agricultural characteristics. It is also classified according to the flora where the bees collect the resins, which represent the raw material for propolis production. Propolis possesses high antioxidant activity determined by its phenolic compounds. Due to diverse composition and possible impact on human health, eight samples of propolis were evaluated for their phenolic composition and antioxidant activity. Samples of Polish, Romanian, Turkish and Uruguayan origin propolis were used for phenolic spectrum determination using high performance liquid chromatography and photodiode array detection and in vitro DPPH and ABTS methods were used to determine the antioxidant activity of the extracts. PCA and HCA models were applied to evaluate the correlation between isolated polyphenols and antioxidant activity. The results confirmed variability in propolis composition depending on the geographical region of collection and the plant sources, and correlation between chemical composition and antioxidant activity. Results of PCA and HCA analyses confirm that Polish propolis is similar to that from different provinces of Romania, while Turkish and Uruguay are completely different. Polish and Romanian propolis belong to the poplar type. The assessed phenolic compounds of propolis samples used in the study are responsible for its antioxidant effect. The observed antioxidant activity of the analyzed samples may suggest directing subsequent research on prophylactic and therapeutic properties concerning cardiovascular, metabolic, neurodegenerative, and cancerous diseases, which are worth continuing.