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Environmental Monitoring and Simulation of Infrasound Generating Mechanism of Traffic Flow

Grafkina Marina Vladimirovna, Nyunin Boris Nikolaevich, Sviridova Evgeniya Yurevna

Journal of Ecological Engineering

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2019

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Vol. 20, nr 7

90--97

EN

Ground vehicles are the main sources of noise and infrasounds in residential areas. Numerous published works are devoted to the studies of audible sound, its sources in vehicle, and development of measures to its reduction. The authors believe that the problem of infrasound occurrence and propagation in residential areas and – hence – its negative impact on humans and ambient environment is underestimated. Development of predictions and experimental methods of studying the infrasound generating mechanism and environmental monitoring of this negative factor are an urgent issue. A significant portion of acoustic emission from a vehicle comprises infrasound and low frequency range. Internal and external infrasound of vehicle were measured. A prediction model was proposed and the influence of vehicle design features on the infrasound level was estimated. Predictions of the external infrasound generating the mechanism of vehicles reveal that its frequency and level depend on driving speed, drag coefficient, vehicle body length, and Strouhal number Wheels, which execute rotation and progressive movement in airstream, are important sources of vehicle infrasound. Five wheel harmonics were calculated for motor vehicles at various driving speeds, the existing dependences are detected. It was demonstrated that the regulatory levels of infrasound can be exceeded only in residential areas adjacent to traffic flow with driving speeds higher than 80 km/h. The results of field studies of infrasound level on the streets of Moscow were presented. Recommendations on the development of environmental monitoring and main approaches to reduce infrasound in urban environment were given.

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Data Linkage Dynamics with Shedding

Bergstra J.A., Middelburg C.A.

Fundamenta Informaticae

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2010

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Vol. 103, nr 1-4

31-52

EN

We study shedding in the setting of data linkage dynamics, a simple model of computation that bears on the use of dynamic data structures in programming. Shedding is complementary to garbage collection. With shedding, each time a link to a data object is updated by a program, it is determined whether or not the link will possibly be used once again by the program, and if not the link is automatically removed. Thus, everything is made garbage as soon as it can be viewed as garbage. By that, the effectiveness of garbage collection becomes maximal.

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Multi-Shed Rotational Formation (Along the Warp) of Woven Structures

Szosland J.

Fibres & Textiles in Eastern Europe

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2003

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Vol. 11, no. 2 (41)

32--36

EN

A new concept and implementation is presented of multi-shedding based on rotational formation of woven structures along the warp. The difference between the hitherto designed rotational constructions and that presented in this article is stressed. In contrast to the aim of previous designers (to achieve more efficient looms), the author emphasises the possibility of weaving woven structures with the use of warp and weft threads of complex surface and cross-section structures which, up to the present, could not be formed by means of modern weaving machines. The basic principles of the disk shed-forming and the assemblies used for them are presented. The new loom has been verified by weaving various woven structures hitherto impossible to obtain, for example such as woven fabrics with roving or selvedges from air-jet looms used as warp threads, woven structures with pile loop and double-woven fabrics. The possibility to manufacture complex woven structures by means of simple constructions and with the use of very cheap raw material is given special emphasis.

PL

Przedstawiono nową koncepcję oraz realizację wieloprzesmykowego rotacyjnego formowania struktur tkanych wzdłuż osnowy. W przeciwieństwie do wcześniejszych wynalazców, zmierzających do zwiększenia wydajności krosna, autor podkreśla zalety nowej, prostej konstrukcji, polegające na możliwości tkania struktur z zastosowaniem na nitki osnowy i wątku wyrobów liniowych o rozbudowanej strukturze powierzchni i przekroju poprzecznego, które jak dotychczas nie mogły być stosowane w procesie tkania. Przedstawiono zasady tarczowej koncepcji formowania przesmyku. Praca nowego krosna została zweryfikowana poprzez tkanie różnych struktur, dotychczas niemożliwych do osiągnięcia, np. przy zastosowaniu niedoprzędu lub krajek z krosien pneumatycznych, tkanin z obywa pętelkową i tkanin podwójnych. Podkreślono możliwości produkcji złożonych struktur tkackich z tanich surowców.

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Determination of the Crossing Resistance of Warp Threads in Shed Formation

Kuchar M., Słodowy J.

Fibres & Textiles in Eastern Europe

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2002

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Nr 2 (37)

39--41

EN

The resistance that has to be overcome by the warp threads in shedding is important, because of the degree of destruction of the threads and the amount of work expended on the formation of the shed. A method is presented of measuring the resisting force, together with the relevant test arrangement and test conditions. Some curves of variation of the force with time and distance are also presented, and the curves are analysed with the objective of revealing their characteristic features. The work involved with crossing the warp in shedding and the amount of energy dissipated in this operation is determined and analysed. The character of damping the warp motion is also determined. Upon qualitative analysis of the curves of the forces, the crossing resistance of the warp threads in shedding is decomposed into friction between the crossing threads and friction between the threads and their respective healds. The accurately established empirical data is used for verifying the shedding models described in the relevant literature.

PL

Siła oporu pokonywana przez mijające się nitki osnowy podczas zmiany przesmyku jest istotna z uwagi na ich niszczenie oraz na nakład pracy łożony na tworzenie przesmyku. W artykule przedstawia się metodę pomiaru tej siły, stanowisko badawcze warunki pomiaru. Prezentuje się przykładowe przebiegi siły w funkcji czasu i drogi i dokonuje ich analizy pod kątem wydobycia charakterystycznych cech; określa się i bada pracę mijania osnowy i energię dyssypowaną podczas tej czynności oraz określa charakter tłumienia ruchu osnowy. Na podstawie jakościowej analizy charakterystyk siłowych rozkłada się opór mijania na tarcie między gałęziami nitek i tarcie o struny nicielnic współpracujących. W oparciu o dokonane empirycznie ustalenia przeprowadzono weryfikację modeli otwierania przesmyku opisywanych w literaturze.

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Shedding without dynamic warp loading. The possibility of forming a new woven structure

Szosland J.

Autex Research Journal

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2002

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Vol. 2, no. 1

38--45

EN

The shedding without dynamic warp loading is presented by a loom structure with the use of assembles of multi-angle shedding disks, e.g. quadrangular shedding disks and disks for increasing weft density. Several sets of these assembles form the rotating weaving drum, which is electronically controlled. The new machine loom, the multi-layer rotational weaving machine, allows the manufacture of completely new woven fabric structures, which until now was impossible to achieve with the use of conventional weaving machines. Woven fabrics can be manufactured with the use of warp and weft threads of extremely low tenacity, loose structure and strong developed surface, as can grid structures and woven structures with pile loop. The possibility to utilise unspinnable yarn, roving and selvedges was demonstrated on a model weaving machine specially constructed for the tests.