Wyniki wyszukiwania - Biblioteka Nauki

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Comparative Simulation of the Production Flow with the Implementation of Kanban and DBR

100%

Tomaszewska K.

Management and Production Engineering Review

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2023

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tom Vol. 14, No. 2

79--87

EN

Currently, we live in a culture of being overly busy, but this does not translate into efficiency, speed of implementation of the actions taken. Enterprises are constantly looking for methods and tools to make them more efficient. The most popular method of production management is Lean Manufacturing, less known is Theory of Constraints. This work is a continuation of the research on the comparison of these methods with apply a computer simulation, which the analyzed production process in the selected enterprise, after 24 hours and week. An attempt was made to simplify the comparison of the methods based on the obtained simulation in terms of costs. In analyzed case, more advantageous solution is to use the DBR method. To produce various orders that do not require 100% production on the bottleneck position, the use of Kanban is a frequent practice as it provides greater flexibility in order execution.

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Polimerobeton zbrojony krótkimi włóknami szklanymi, z dodatkiem odpadowego szkła kineskopowego

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Smoleń J. , Tomaszewska K. , Junak G. , Kozioł M.

Cement Wapno Beton

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2022

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tom R. 27, nr 2

102--114

PL

W pracy omówiono wykorzystanie odpadowego szkła kineskopowego, do wytwarzania polimerobetonów. Szkło kineskopowe poddano kilkakrotnemu rozdrabnianiu, w celu otrzymania ziaren mniejszych od 2 mm. Utworzono szereg polimerobetonów wzmocnionych hybrydowo: zmielonym szkłem kineskopowym, piaskiem oraz pociętym włóknem szklanym, o długości 4,5 mm i 12 mm. Zbadano wpływ dodatku włókien szklanych i ich długości na właściwości polimerobetonów, z 30% dodatkiem objętościowym żywicy epoksydowej, pełniącej rolę lepiszcza. Przeprowadzono badania szkła kineskopowego, oznaczając jego skład chemiczny, rozkład wielkości cząstek i budowę ziaren. Oznaczono wytrzymałość na zginanie i na ściskanie oraz porowatość otwartą, gęstość pozorną i nasiąkliwość wodą. Wyniki badań wykazały, że polimerobetony z dodatkiem zmielonego szkła kineskopowego, są dobrą metodą na zagospodarowanie, tego nietypowego odpadu. Uzyskane polimerobetony mają kilkukrotnie lepsze właściwości mechaniczne niż tradycyjne betony oraz znacznie mniejszą porowatość i nasiąkliwość wodą, co czyni ten materiał korzystny do produkcji wyrobów cienkościennych oraz narażonych na działanie wody i odczynników chemicznych. Dodatek ciętych włókien szklanych powoduje poprawę właściwości mechanicznych polimerobetonów, a także chroni ten materiał, przed gwałtowną dezintegracją, po przekroczeniu maksymalnych naprężeń. Jest to niezwykle ważne dla bezpieczeństwa użytkowania konstrukcji, w przypadku awarii.

EN

This paper describes the use of CRT glass waste for the production of polymer concrete. The CRT glass was subjected to a multistage mechanical disintegration process, in a way that allowed obtaining grains smaller than 2 mm. A set of hybrid reinforced polymer concrete was produced by using: ground CRT glass, sand and cut glass fibers 4.5 mm and 12 mm long. The influence of the volume of fibers and the length of glass fibers on the properties of polymer concrete with 30% by volume of epoxy resin, acting as a binder was described. Tests of CRT glass were carried out, among others study of chemical composition, particle size distribution and analysis of grain morphology. For polymer concrete, the flexural strength and compressive strength were determined, and the open porosity, apparent density, and water absorption were examined. The test results showed that polymer concrete with the use of milled CRT glass is a good way to manage this problematic waste. The polymer concrete has several times better than traditional concretes and significantly lower porosity and water absorption, which makes this material advantageous in applications such as the production of thin-walled products and products exposed to water and chemical attack. The addition of chopped glass fibers leads to an increase in mechanical properties and also protects the material against rapid disintegration after exceeding the maximum stresses, which is extremely important for the safety of use of the structure in the event of a failure.

3

Thermal characterization of curing process in unsaturated polyester resin based polymer concrete

51%

Smoleń J. , Tomaszewska K. , Desisa D. G.

Composites Theory and Practice

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2022

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tom R. 22, nr 3

166--171

EN

This paper presents a description of the temperature changes that take place in the curing system of polymer concrete. The research used polymer concrete composed of 30% by volume unsaturated polyester resin acting as a binder for powder fillers. Among the powder fillers, ground glass waste and sand in a volume ratio of 1:1 were used. The investigations were carried out for three volumes, 10, 100 and 1000 cm3, respectively. The temperature in the central point of the volume (the highest temperature) was measured by the ATD method using a NiCr-NiAl thermocouple, and the temperature on the polymer concrete surface was measured using a thermal imaging camera. The temperature-time course recorded for both the measuring points allowed evaluation of the curing system parameters (gelation time, maximum curing temperature, time to maximum temperature), important for the processing of polymer concrete. Additionally, the knowledge of the temperature curves enabled a mathematical description of the heat flow between the measuring points. The conducted studies proved that the volume of the mold is important for the maximum temperature and curing time. The work is a continuation of previous research focused on polymer concrete and is an extension of information oriented to the industrial aspect. Knowledge of the temperaturę peaks and curing time will allow adjustments to be made to the manufacturing processes.

4

Polymer concrete filled with milled car windshield and GFRP waste

38%

Smoleń J. , Orzechowska K. , Tomaszewska K. , Stępień K. , Peryt A. , Pawlik T.

Composites Theory and Practice

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2023

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tom R. 23, nr 2

84--88

EN

The paper describes the process of preparing polymer concrete consisting of waste materials. The matrix was a poliester terephthalic resin produced from PET bottles, while the fillers were laminated car glass with PVB foil, as well as GFRP waste. The preparation of the fillers consisted in producing appropriate fraction sizes. Using a cross-beater mill, a fine fraction with an average size of 2 mm was obtained. The coarse fraction was achieved after the initial grinding process with a size greater than 2 mm. Two series of samples were created from the prepared materials, with different contents of resin, car glass and GFRP. The compression test and the three-point bending test showed that the obtained polymer concrete containing 1 vol.% GFRP has an average compressive strength of 51.75 MPa and an average flexural strength of 20.49 MPa. The polymer concrete with 2 vol.% GFRP showed an average compressive strength of 75.63 MPa and an average flexural strength of 17.89 MPa. The Archimedes method results showed that the samples with the amount of 1 vol.% GFRP reached 1.11% open porosity and the samples with 2 vol.% GFRP achieved 1.23%. The use of waste materials such as windshields with PVB foil and GFRP composites can be used as fillers in polymer concrete technology.