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  1. Article: Tribochemical Interactions between Graphene and ZDDP in Friction Tests for Uncoated and W-DLC-Coated HS6-5-2C Steel.

    Kowalczyk, Joanna / Madej, Monika / Dzięgielewski, Wojciech / Kulczycki, Andrzej / Żółty, Magdalena / Ozimina, Dariusz

    Materials (Basel, Switzerland)

    2021  Volume 14, Issue 13

    Abstract: ... balls in a sliding contact with uncoated or W-DLC-coated HS6-5-2C steel discs in the presence ...

    Abstract If a lubricant contains structures capable of conducting energy, reactions involving zinc dialkyldithiophosphate (ZDDP) may take place both very close to and away from the solid surfaces, with this indicating that ZDDP can be a highly effective anti-wear (AW) additive. The central thesis of this article is that the tribocatalytic effect is observed only when the energy emitted by the solids is transmitted by ordered molecular structures present in the lubricant, e.g., graphene. The friction tests were carried out for 100Cr6 steel balls in a sliding contact with uncoated or W-DLC-coated HS6-5-2C steel discs in the presence of polyalphaolefin 8 (PAO 8) as the lubricant, which was enhanced with graphene and/or ZDDP. There is sufficient evidence of the interactions occurring between ZDDP and graphene and their effects on the tribological performance of the system. It was also found that the higher the concentration of zinc in the wear area, the lower the wear. This was probably due to the energy transfer resulting from the catalytic decomposition of ZDDP molecules. Graphene, playing the role of the catalyst, contributed to that energy transfer.
    Language English
    Publishing date 2021-06-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma14133529
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Functional Properties and Storage Stability of Astaxanthin-Loaded Polysaccharide/Gelatin Blend Films-A Comparative Study.

    Łupina, Katarzyna / Kowalczyk, Dariusz / Kazimierczak, Waldemar

    Polymers

    2022  Volume 14, Issue 19

    Abstract: Edible films were obtained from the aqueous binary 75/25 blends of polysaccharides (carboxymethyl cellulose (CMC), gum Arabic (GAR), octenyl succinic anhydride starch (OSA), and water-soluble soy polysaccharides (WSSP)) and gelatin (GEL) supplemented ... ...

    Abstract Edible films were obtained from the aqueous binary 75/25 blends of polysaccharides (carboxymethyl cellulose (CMC), gum Arabic (GAR), octenyl succinic anhydride starch (OSA), and water-soluble soy polysaccharides (WSSP)) and gelatin (GEL) supplemented with increasing concentrations (0, 0.25, 0.5, and 1%
    Language English
    Publishing date 2022-09-24
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2527146-5
    ISSN 2073-4360 ; 2073-4360
    ISSN (online) 2073-4360
    ISSN 2073-4360
    DOI 10.3390/polym14194001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Effect of Nitrogen Fertilization of Apple Orchard on Soil Mineral Nitrogen Content, Yielding of the Apple Trees and Nutritional Status of Leaves and Fruits

    Kowalczyk, Wojciech / Wrona, Dariusz / Przybyłko, Sebastian

    Agriculture. 2022 Dec. 17, v. 12, no. 12

    2022  

    Abstract: Contemporary trends in horticulture are aimed at limiting the use of mineral fertilizers to the necessary minimum, which is to guarantee adequate profitability of production while maintaining high-quality fruit and at the same time preventing ... ...

    Abstract Contemporary trends in horticulture are aimed at limiting the use of mineral fertilizers to the necessary minimum, which is to guarantee adequate profitability of production while maintaining high-quality fruit and at the same time preventing environmental pollution. Thus, in the presented study, we investigate the effect of diversified nitrogen fertilization on soil mineral nitrogen content during vegetation season, yielding of apple trees and the nutritional status of apple leaves and fruits. We compared several ammonium nitrate treatments as well as growth without fertilization as a control. The results of our study show that under the conditions of humus-rich soils and with appropriate agrotechnics, N mineralization from the organic matter available in the soil may completely cover demand of apple trees for this component. Achieved outcomes clearly revealed that nitrogen fertilization in the amount of 100 kg N · ha⁻¹ on the entire soil surface carries a real risk of groundwater contamination, and the same nitrogen dose applied within the grassland does not bring any production effects, therefore it should be considered as unjustified. Obtained results revealed that in a rationally managed, fully fruiting apple orchard, the annual dose of N should not exceed 50 kg N∙ha⁻¹. This dosage of N should fully secure the nutritional needs of apple trees, guaranteeing their high yield and complete safety for the environment. What is important is, nitrogen fertilization strongly affects macroelemental composition of apple leaves and fruits.
    Keywords agriculture ; ammonium nitrate ; apples ; fruits ; grasslands ; groundwater contamination ; horticulture ; mineralization ; nitrogen ; nitrogen content ; nutritional status ; orchards ; organic matter ; profitability ; risk ; soil ; soil minerals
    Language English
    Dates of publication 2022-1217
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article ; Online
    ZDB-ID 2651678-0
    ISSN 2077-0472
    ISSN 2077-0472
    DOI 10.3390/agriculture12122169
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Gum Arabic/Gelatin and Water-Soluble Soy Polysaccharides/Gelatin Blend Films as Carriers of Astaxanthin-A Comparative Study of the Kinetics of Release and Antioxidant Properties.

    Łupina, Katarzyna / Kowalczyk, Dariusz / Kazimierczak, Waldemar

    Polymers

    2021  Volume 13, Issue 7

    Abstract: Polymer blending and incorporation of active substances offer a possibility of generation of novel packaging materials with interesting features. Astaxanthin is one of the most powerful antioxidants. Hence, in this study, water-soluble AstaSana ... ...

    Abstract Polymer blending and incorporation of active substances offer a possibility of generation of novel packaging materials with interesting features. Astaxanthin is one of the most powerful antioxidants. Hence, in this study, water-soluble AstaSana astaxanthin (AST) was incorporated into 75/25 gum arabic/gelatin (GAR75/GEL25) and water-soluble soy polysaccharides/gelatin (WSSP75/GEL25) blend films in different concentrations (0, 0.25%, 0.5%, 1%). Microscope images showed good compatibility between the polysaccharides and GEL. Basing on time required for 50% release, the WSSP-based film exhibited an approximately four-fold slower release rate (t
    Language English
    Publishing date 2021-03-28
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2527146-5
    ISSN 2073-4360 ; 2073-4360
    ISSN (online) 2073-4360
    ISSN 2073-4360
    DOI 10.3390/polym13071062
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Tribocorrosion and Abrasive Wear Test of 22MnCrB5 Hot-Formed Steel.

    Ulbrich, Dariusz / Stachowiak, Arkadiusz / Kowalczyk, Jakub / Wieczorek, Daniel / Matysiak, Waldemar

    Materials (Basel, Switzerland)

    2022  Volume 15, Issue 11

    Abstract: The article presents the results of research on abrasive and tribocorrosion wear of boron steel. This type of steel is used in the automotive and agricultural industries for the production of tools working in soil. The main goal of the article is the ... ...

    Abstract The article presents the results of research on abrasive and tribocorrosion wear of boron steel. This type of steel is used in the automotive and agricultural industries for the production of tools working in soil. The main goal of the article is the evaluation of tribocorrosion and abrasive wear for hot-formed 22MnCrB5 steel and a comparison of the obtained results with test results for steel in a cold-formed state. The spinning bowl method to determine the wear of samples working in the abrasive mass was used. Furthermore, a stand developed based on the ball-on-plate system allows to determine the wear during the interaction of friction and corrosion. After the hot-forming process, 22MnCrB5 steel was three times more resistant for the abrasive wear than steel without this treatment. The average wear intensity for 22MnCrB5 untreated steel was 0.00046 g per km, while for 22MnCrB5 hot-formed steel it was 0.00014 g per km. The tribocorrosion tests show that the wear trace of hot-formed 22MnCrB5 steel was about 7.03 µm, and for cold-formed 22MnCrB5 steel a 12.11 µm trace was noticed. The hot-forming method allows to obtain the desired shape of the machine element and improves the anti-wear and anti-corrosion properties for boron steel.
    Language English
    Publishing date 2022-05-30
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma15113892
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Modeling the Depth of Surface Cracks in Brake Disc.

    Sawczuk, Wojciech / Jüngst, Mateusz / Ulbrich, Dariusz / Kowalczyk, Jakub

    Materials (Basel, Switzerland)

    2021  Volume 14, Issue 14

    Abstract: The article presents the state of knowledge and research in the field of surface cracks occurring in disc braking systems of rail and car vehicles. The craze formed during the operation of vehicles is particularly dangerous and leads to breaking the disc ...

    Abstract The article presents the state of knowledge and research in the field of surface cracks occurring in disc braking systems of rail and car vehicles. The craze formed during the operation of vehicles is particularly dangerous and leads to breaking the disc into several pieces. It may lead to a loss of braking force and damage to the entire disc brake caliper. The main aim of the research is to identify surface cracks in brake discs made of cast iron and use experimental methods to estimate their depth. Research were conducted on the disc braking system developed by the authors. In examining the location and depth of cracks, the penetration method, ultrasound, as well as a special probe were used. This device measures the crack depth based on the electrical resistance between two points on the surface of the metallic object. The tests showed that the first microcracks on the brake discs appeared after 309 braking tests on the test stand. In addition, it was observed that the surface cracks length of the disc increased linearly to depth until they reached about 11.5-12 mm with corresponded to crack lengths in the range of 65-70 mm. However, determination of the regression functions presented in the article allows to estimate the depth of surface cracks up to 70 mm long on cast iron brake discs by measuring their length.
    Language English
    Publishing date 2021-07-12
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma14143890
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Evaluation of Wear of Disc Brake Friction Linings and the Variability of the Friction Coefficient on the Basis of Vibroacoustic Signals.

    Sawczuk, Wojciech / Ulbrich, Dariusz / Kowalczyk, Jakub / Merkisz-Guranowska, Agnieszka

    Sensors (Basel, Switzerland)

    2021  Volume 21, Issue 17

    Abstract: The article presents the results of friction and vibroacoustic tests of a railway disc brake carried out on a brake stand. The vibration signal generated by the friction linings provides information on their wear and offers evaluation of the braking ... ...

    Abstract The article presents the results of friction and vibroacoustic tests of a railway disc brake carried out on a brake stand. The vibration signal generated by the friction linings provides information on their wear and offers evaluation of the braking process, i.e., changes in the average friction coefficient. The algorithm presents simple regression linear and non-linear models for the thickness of the friction linings and the average coefficient of friction based on the effective value of vibration acceleration. The vibration acceleration signals were analyzed in the amplitude and frequency domains. In both cases, satisfactory values of the dynamics of changes above 6 dB were obtained. In the case of spectral analysis using a mid-band filter, more accurate models of the friction lining thickness and the average coefficient of friction were obtained. However, the spectral analysis does not allow the estimation of the lining thickness and the friction coefficient at low braking speeds, i.e., 50 and 80 km/h. The analysis of amplitudes leads to the determination of models in the entire braking speed range from 50 to 200 km/h, despite the lower accuracy compared to the model, based on the spectral analysis. The vibroacoustic literature presents methods of diagnosis of the wear of various machine elements such as bearings or friction linings, based on amplitude or frequency analysis of vibrations. These signal analysis methods have their limitations with regard to their scope of use and the accuracy of diagnosis. There are no cases of simultaneous use of different methods of analysis. This article presents the simultaneous application of the amplitude and frequency methods in the analysis of vibroacoustic signals generated by brake linings. Moreover, algorithms for assessing the wear of friction linings and the average coefficient of friction were presented. The algorithm enables determination of the time at which the friction linings should be replaced with new ones. The final algorithm analyzes the vibration acceleration signals using both amplitude analysis for low braking speeds, as well as spectral analysis for medium and high braking speeds.
    MeSH term(s) Friction ; Vibration
    Language English
    Publishing date 2021-09-03
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2052857-7
    ISSN 1424-8220 ; 1424-8220
    ISSN (online) 1424-8220
    ISSN 1424-8220
    DOI 10.3390/s21175927
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Modeling the Average and Instantaneous Friction Coefficient of a Disc Brake on the Basis of Bench Tests.

    Sawczuk, Wojciech / Cañás, Armando Miguel Rilo / Ulbrich, Dariusz / Kowalczyk, Jakub

    Materials (Basel, Switzerland)

    2021  Volume 14, Issue 16

    Abstract: This article presents the results of tests conducted on the average and instantaneous friction coefficients of railway vehicle disc brakes. The tests were carried out independently of various states of wear on the friction linings and the brake disc. The ...

    Abstract This article presents the results of tests conducted on the average and instantaneous friction coefficients of railway vehicle disc brakes. The tests were carried out independently of various states of wear on the friction linings and the brake disc. The requirements of the International Union of Railways (UIC) regarding the approval of brake linings for use were taken into account. Based on many years of research using a brake bench to test railway disc brakes, the authors developed multiple regression models for the average friction coefficient and fluctuations (tolerances) in the instantaneous friction coefficient and achieved 870 results. The models proposed three types of variables: the input braking parameters (speed, pressure, and mass to be braked), operational parameters (the wear on the friction linings and the brake disc), and design parameters (perforations in the form of holes on the disc surface). The above two models were validated on the basis of 384 brakes, and in subsequent stages a further evaluation was performed. The coefficients were determined to be, respectively, 0.99 for the model of the average friction coefficient and 0.71 for the model of tolerance (fluctuations) of the instantaneous friction coefficient.
    Language English
    Publishing date 2021-08-23
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma14164766
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: Investigation and Modelling of the Weight Wear of Friction Pads of a Railway Disc Brake.

    Sawczuk, Wojciech / Merkisz-Guranowska, Agnieszka / Ulbrich, Dariusz / Kowalczyk, Jakub / Cañás, Armando-Miguel Rilo

    Materials (Basel, Switzerland)

    2022  Volume 15, Issue 18

    Abstract: This paper presents the results of tests on the railway disc brake with regard to the weight wear of friction pads. The tests were carried out at a certified brake test bench where the friction-mechanical characteristics of the railway brake were ... ...

    Abstract This paper presents the results of tests on the railway disc brake with regard to the weight wear of friction pads. The tests were carried out at a certified brake test bench where the friction-mechanical characteristics of the railway brake were determined. The test stand was additionally equipped with a thermal imaging camera to observe the contact between the brake pads and the brake disc. The scientific goal of the test is to evaluate the relationship between the weight wear of friction pads and the quantities characterizing the braking process. The quantities characterizing the braking process included pad-to-disc contact area, friction pad thickness, pad-to-disc pressure, and braking speed. A regression model to estimate the friction pad wear on the basis of a single braking with the given input quantities was determined. The greatest influence on the increase in weight wear of friction pads has the braking velocity, which was confirmed by the value of the correlation coefficient of the regression model at value 0.81. The pressure of the friction pad to the disc and the friction pad thickness do not have a significant effect on the weight wear described by the regression model, and the obtained correlation coefficient for these parameters was lower than the value of 0.2.
    Language English
    Publishing date 2022-09-12
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2487261-1
    ISSN 1996-1944
    ISSN 1996-1944
    DOI 10.3390/ma15186312
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Inherently acidic films based on chitosan lactate-doped starches and pullulan as carries of nisin: A comparative study of controlled-release and antimicrobial properties.

    Kowalczyk, Dariusz / Karaś, Monika / Kordowska-Wiater, Monika / Skrzypek, Tomasz / Kazimierczak, Waldemar

    Food chemistry

    2022  Volume 404, Issue Pt B, Page(s) 134760

    Abstract: Nisin (NIS) Z was incorporated (0.05 %, 0.1 %, 0.2 %) into edible films based on chitosan lactate (CHL) and 75/25 blends of polysaccharides (corn starch (CS), wheat starch (WS), oxidized potato starch (OPS), pullulan (PUL)) with CHL. The increase in the ... ...

    Abstract Nisin (NIS) Z was incorporated (0.05 %, 0.1 %, 0.2 %) into edible films based on chitosan lactate (CHL) and 75/25 blends of polysaccharides (corn starch (CS), wheat starch (WS), oxidized potato starch (OPS), pullulan (PUL)) with CHL. The increase in the NIS/polymer ratio promoted the diffusion-driven release. Compared with the fully dissolvable CHL and PUL/CHL carriers, the starch/CHL films had limited solubility (≈27-37 %) and, consequently, ensured slower/incomplete release of NIS. The assayable NIS half-release times, determined in water, ranged from <1 min to ∼13 h. Probably due to the similar pH (≈4.5), there were generally no large differences between the antibacterial activities of the formulations. The NIS-supplemented systems limited the growth of some pathogens (B. cereus, L. monocytogenes, S. aureus), phytopathogens (P. carotovorum), and bacterial starter cultures. The NIS improved the UV-blocking ability of the films, but the 0.2 % NIS addition weakened (by ≈17-32 %) the tensile strength of most of the films.
    MeSH term(s) Nisin/pharmacology ; Chitosan/pharmacology ; Lactic Acid ; Staphylococcus aureus ; Delayed-Action Preparations ; Anti-Bacterial Agents/pharmacology ; Anti-Infective Agents ; Starch
    Chemical Substances Nisin (1414-45-5) ; pullulan (8ZQ0AYU1TT) ; Chitosan (9012-76-4) ; Lactic Acid (33X04XA5AT) ; Delayed-Action Preparations ; Anti-Bacterial Agents ; Anti-Infective Agents ; Starch (9005-25-8)
    Language English
    Publishing date 2022-10-28
    Publishing country England
    Document type Journal Article
    ZDB-ID 243123-3
    ISSN 1873-7072 ; 0308-8146
    ISSN (online) 1873-7072
    ISSN 0308-8146
    DOI 10.1016/j.foodchem.2022.134760
    Database MEDical Literature Analysis and Retrieval System OnLINE

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