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1

Modelling of selective retention of Cd-Ni ions from aqueous solutions by polymer enhanced ultrafiltration

Can Muhammed F., Arslan Fatma, Çelik Mehmet S.

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 151913

EN

Polymer enhanced ultrafiltration (PEUF) technique economically enables separation and/or retention of various heavy metal ions from aqueous solutions for environmental and engineering problems. Polyethylenimine as the water-soluble complexation agent utilized to interact with heavy metal ions of Cd and Ni as cations in ultrafiltration experiments were modeled with protonation data to understand the mechanism. Test runs showed that an enrichment coefficient (the ratio of Cd over Ni in permeate) up to 10 was obtained at pH 4.2 in the temperature range of 20-22oC, whereas full retention of both cations is possible above pH 5.0 and those results are highly compatible with the model developed.

2

Machine learning prediction of future peripheral neuropathy in type 2 diabetics with percussion entropy and body mass indices

Xiao Ming-Xia, Lu Chang-Hua, Ta Na, Wei Hai-Cheng, Haryadi Bagus, Wu Hsien-Tsai

Biocybernetics and Biomedical Engineering

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2021

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Vol. 41, no. 3

1140--1149

EN

This study was designed to evaluate the clinical applications of body mass index (BMI) and a percussion-entropy-based index (PEINEW) for predicting the development of diabetic peripheral neuropathy (DPN) in a group of type 2 diabetes mellitus (DM) patients. The study population comprised a sample of 90 subjects with diabetics (aged 37–86 years), who went through a blood test and photoplethysmography (PPG) measurement and were then followed for 5.5 years. Conventional parameters, including the small-scale multiscale entropy index (MEISS), pulse wave velocity with electrocardiogram located (PWVmean), and PEIoriginal, were computed and compared. A logistic regression model with PEINEW and a single categorical variable (BMI) showed a graded association between the diabetics, with a high BMI (i.e., ‘‘high” category) associated with a 12.53-fold greater risk of developing DPN relative to the diabetics with a low BMI (i.e., ‘‘low” category) (p = 0.001). The odds ratio for PEINEW was 0.893. The Kaplan-Meier survival analysis showed that the diabetic patients with BMI ＞ 30 had a significantly higher cumulative incidence of PN on follow-up than those with BMI [...] 30 (log-rank test, p < 0.001). These findings suggest that BMI and PEINEW are both important risk and protective factors for new-onset DPN from diabetes mellitus and, thus, BMI and percussion entropy calculation can provide valid information that may help to identify diabetics with a high BMI and a low PEINEW as being at increased risk of future DPN.

3

The effect of the ionizing radiation on the tribological properties of thermoplastic polymers rubbing against steel

Niemiec A., Kujawa M., Wieleba W.

Tribologia

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2016

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nr 5

133--145

EN

The paper describes the effects of gamma radiation doses on the tribological and mechanical properties of selected thermoplastic polymers: PEEK, PEI, PET, and PA6. Samples of those polymers were irradiated with gamma rays of energy 1, 1.2, 3, 4, 5 MeV and with the intensity of the radiation beam 4, 7, 10, 30, 40 μA. With an increasing dose of radiation, properties such as microhardness, the friction coefficient of polymers, and the wear rate are changed. The chemical structure of the irradiated polymer may be changed by crosslinking but also by chain scission. The modified polymers may be used in medical science, electronics, and space technology. In this article, we report the results of steel C45 – thermoplastics (PEEK, PEI, PET, and PA6) friction couple during the slip motion. The analysis is focused on the friction coefficient, wear rate, and microhardness. Kinematic parameters of the experiment in slide movement were constant and defined by the following values: contact pressure p = 1MPa and sliding velocity v = 1m/s. The authors observed that, as gamma radiation dose increased, the microhardness and friction coefficient increased and their wear intensity decreased. Polymers change their microstructure and molecular structure when they are subjected to gamma ray irradiation, which results in modification on many important physical and chemical properties.

PL

Celem niniejszej pracy było określenie wpływu dawki promieniowania gamma na właściwości tribologiczne i mechaniczne wybranych polimerów termoplastycznych: PEEK, PEI, PET, PA6. Wraz ze wzrostem dawki tego promieniowania właściwości takie jak microhardness, współczynnik tarcia statycznego oraz intensywność zużycia ulegają zmianie. Wymienione właściwości mogą być modyfikowane na skutek zachodzących zmian w strukturze chemicznej naświetlonych polimerów poprzez sieciowanie łańcuchów polimerowych, ale także ich rozerwanie. Zmodyfikowane polimery mogą być wykorzystane m.in. w medycynie, elektronice i technologii kosmicznej. W pracy opisano badania par ślizgowych stal C45 – wybrany polimer. Analizie poddano wartości współczynnika tarcia statycznego oraz intensywności zużycia materiału. Dla wszystkich analizowanych przypadków wartości parametrów ruchowych były stałe: siła nacisku wynosiła 1 MPa, a prędkość ślizgowa 1 m/s. Eksperyment wykazał zwiększenie wartości mikrotwardości i współczynnika tarcia oraz zmniejszenie intensywności zużycia.

4

Badania odporności na zużycie ścierne wybranych polimerów inżynieryjnych

Capanidis D., Tański A.

Tribologia

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2012

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nr 4

25-32

PL

W artykule przedstawiono wyniki tribologicznych badań porównawczych odporności na zużywanie ścierne wybranych polimerów inżynieryjnych: PA6, PEEK, PEI, PET, PSU. Do badań wykorzystano stanowisko badawcze Tester T-07. Badania prowadzono w obecności luźnego ścierniwa, którym był elektrokorund F90, przy zachowaniu jednakowych warunków tarcia dla wszystkich badanych materiałów. W celu wyjaśnienia przyczyn różnej odporności na zużycie ścierne badanych polimerów przeprowadzono badania mikrotwardości ich powierzchni trących przed i po procesie ścierania oraz dokonano próby powiązania odporności na zużywanie ścierne poszczególnych polimerów z ich podstawowymi własnościami wytrzymałościowymi.

EN

The paper presents the results of comparative studies of abrasive wear resistance of selected engineering polymers: PA6, PEEK, PEI, PET, PSU. The study used a research position Tester T-07. The research testing stand Tester T-07 was used for a study. The study was conducted in the presence of loose abrasive, which was the F90 corundum, while maintaining the same friction conditions for all tested materials. In order to clarify the causes of various abrasive wear resistance of investigated polymers, the testing of microhardness of friction surfaces before and after abrasion was conducted, and the attempt to link abrasive wear resistance of various polymers with their fundamental strength properties was also done.