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1

Review and reassessment the radius of pedestrian accessibility to catering establishments

Troshkin Arsenii

Przestrzeń i Forma

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2021

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nr 48

223--240

EN

This article deals with the issues regarding the accommodation of catering establishments in a residential area and to ensure pedestrian accessibility to them to save time and reduce the load on the city's transport system. It is based on a three-stage service system and the average walking speed of the economically active population. To solve the unsatisfactory location of catering establishments in a residential area, a formula for calculating the service radius for each type of catering establishment, and classify catering establishments into fast, leisure, and mixed types are proposed. To conclude, with the implementation of the attached calculations in urban planning, the location of types of catering establishments in the residential area could solve the set goals.

PL

W artykule omówiono zagadnienia związane z zakwaterowaniem placówek gastronomicznych na obszarze mieszkalnym oraz zapewnieniem do nich dostępu dla pieszych w celu zaoszczędzenia czasu i odciążenia systemu transportowego miasta. Badanie to opiera się na trzystopniowym systemie obsługi i średniej prędkości chodzenia ludności aktywnej zawodowo. Aby rozwiązać niezadowalającą lokalizację placówek gastronomicznych w dzielnicy mieszkalnej, proponuje się formułę obliczania promienia obsługi dla każdego rodzaju placówki gastronomicznej oraz klasyfikację placówek gastronomicznych na typy szybkie, rekreacyjne i mieszane. Reasumując, dzięki zastosowaniu załączonych obliczeń w urbanistyce, lokalizacja typów lokali gastronomicznych na obszarze mieszkalnym może rozwiązać założone cele.

2

Adsorption efficiency of selected natural and synthetic sorbents

Pavolova H., Bakalar T., Puskarova P.

Geology, Geophysics and Environment

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2016

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Vol. 42, no. 1

114--115

EN

Sorbents are substances binding other substances on their surface. Effective sorbents have a porous surface. The adsorption activity of the surface is closely related to the local radius of curvature of surface irregularities. Suitable sorbents are natural and synthetic solids of amorphous or microcrystalline structure (Kyncl et al. 2008). Globally, the following adsorbents are the most used: activated carbon, zeolites, silica gel, activated alumina (Bakalár et al. 2005). A characteristic of effective adsorbents is large surface area of hundreds of square meters multiply by gram to the power of minus one [m 2 ∙g −1 ]. Other important features of adsorbents include specific volume, porosity, average pore diameter, pore distribution, etc. Some natural materials or industrial waste with high adsorption capacity, which naturally reduces the overall cost of their disposal, can be used for adsorption of heavy metal cations. Some of low-cost sorbents are: lignin, chitin, seaweed/ algae, zeolites, clays, fly-ash, peat, sand grains coated with iron oxide, modified cotton and wool (Pavolová et al 2006). In experiments of Cu and Zn removal from wastewater the following adsorbents were used (Bakalár et al. 2005): - Lewatit S100, which is strongly acidic, gel-like cationic ion exchange resin with particles of equal size based on styrene-divinylbenzene copolymers. Monodisperse beads are chemically and osmotically highly stable. - Chitosan, which is prepared from chitin, naturally occurring in the shells of crustaceans, by deacetylation using strongly alkaline solution. Chitin is a homopolymer composed of β-(1-4)- -N-acetyl-D-glucosamine. The ability of crustaceans shells to bind metal ions is assigned to the presence of exoskeleton in the molecule of chitin and chitosan. - Synthetic zeolite, which is included in the group of aluminosilicates, was prepared by zeolitization of fly-ash from energy industry. - Bentonite, which is included in the group of hydrated aluminosilicates, the main ingredient is mineral montmorillonite. - Slovakit, which is an inorganic composite sorbent made from pure natural ingredients. Its composition is a subject of patent protection. The aspect of time, i.e. the time the specific sorbent reaches the maximum adsorption capacity for the heavy metal removed, is also important in removal of Cu 2+, Zn 2+ and Pb 2+ cations. The experimental measurements of cations adsorption using the above mentioned sorbents are made at the initial concentration of 10 mg∙L −1 of heavy metal. The time to reach the equilibrium for all sorbent during separation of Cu 2+ cations from model solutions of wastewater was about 60 seconds except for chitosan for which it was almost 2 minutes. This is relatively very good result. The equilibrium of Zn 2+ cations adsorption at the experimental measurements for all the selected sorbents was reached in about 80 seconds except for chitosan for which this time was 2 minutes 5 seconds. This time was on average around 20 minutes longer compared to the adsorption of Cu 2+ ions. The adsorption of Pb 2+ cations was carried out at the experimental measurements in about 83 seconds for all the selected sorbents, except for synthetic zeolite for which the time was 1 min 15 seconds. The adsorption of Pb 2+ cations compared to the cations of Cu 2+ was 23 seconds faster and compared to the cations of Zn 2+ was 3 seconds longer. The most appropriate for the removal of Cu 2+, Zn 2+, and Pb 2+ is Lewatit S100 among the used sorbents; the equilibrium was reached in approximately 35 seconds, 45 seconds, and 83 seconds for Zn 2+, Cu 2+, and Pb 2+, respectively. According to the experimental measurements the longest adsorption time was for chitosan – about 2 minutes for Cu 2+ and Zn 2+, and about 1.5 minutes for Pb 2+.

3

Analiza intensywności pracy wielkiego pieca w zależności od odległości od jego osi

Stachura R.

Hutnik, Wiadomości Hutnicze

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2014

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Vol. 81, nr 4

215--221

PL

W artykule przedstawiono sposób wykorzystania wyników pomiarów sond podwsadowych do analizy intensywności pomiarów zachodzących w przestrzeni roboczej wielkiego pieca w funkcji odległości od jego osi. Jako przykład przedstawiono zmianę stopni redukcji wzdłuż promienia. Metoda ta umożliwia podobną analizę w stosunku do niemal wszystkich parametrów pracy agregatu.

EN

The article shows how to use the measurement results of horizontal probes for the analysis of intensity measurements taking place in the working volume of blast furnace as a function of distance from its center. As an example, changing the reduction ratio along the radius is presented. This method allows a similar analysis applies to almost all the parameters of the unit.

4

Force fit of a hollow shaft in a hub of large radius

Koleif I. A., Kamel M. H.

Mechanics and Mechanical Engineering

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1999

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Vol. 3, nr 2

175--180

EN

In this paper the problem of force fit of a hollow shaft in a hub of large radius is completed under the assumption of plane polar elasticity. Different materials are admitted and radial displacement of the inner and outer radius of the shaft together with that of the hub are allowed. Complete solutions are obtained and are compared with that of the solid shaft. In the case of solid shaft, the results showed that the strain energy is equally shared between the shaft and the hub.