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Experimental investigation of a uniaxial dielectric elastomer generator

Sikora Wojciech

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 4

499--506

EN

The widespread use of battery-powered electronic devices creates the need to develop methods to extend their maximum operating time. This can be achieved by using ambient energy, which would otherwise be dissipated. The conversion of energy, usually mechanical energy, into electric energy takes place in energy harvesters. Energy harvester systems based on a dielectric elastomer (DE) are a relatively new field that is being constantly developed. Due to their features, dielectric elastomer generators (DEGs) may complement the currently dominant piezoelectric harvesters. The major feature of employing a hyperelastic material is that it allows relatively large displacements to be utilised for generating energy, which is impossible in the case of piezoceramics. This article presents a DEG designed to operate under uniaxial tensile loads and which has a multilayer structure, describes the general operating principles of a DEG, explains the construction and assembly process of the investigated design and shows the electric circuit necessary to properly direct current flow during the DEG operation. The experimental part consists of two series of tests based on a central composite design (CCD). The objective of the first part was to map a capacitance response surface of the DEG in the selected range of the cyclic mechanical load. The second part concerned the amount of generated energy for the specific load case as a function of operating voltages. The result of the work is the formulation of regression models that allow the characteristics of the presented DEG design to be identified.

2

2,2’-Oksydietanol : oznaczanie w powietrzu na stanowiskach pracy

Jeżewska A.

Podstawy i Metody Oceny Środowiska Pracy

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2017

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Nr 2 (92)

161--171

PL

2,2’-Oksydietanol (DEG) jest bezbarwną, oleistą cieczą otrzymywaną jako produkt uboczny podczas syntezy glikolu etylenowego. 2,2’-Oksydietanol jest stosowany do produkcji: żywic poliestrowych i akrylowych, poliuretanów i plastyfikatorów. 2,2’-Oksydietanol jest substancją słabo drażniącą. Celem pracy było opracowanie metody oznaczania frakcji wdychalnej 2,2’-oksydietanolu, która umożliwi oznaczanie stężeń 2,2’-oksydietanolu w powietrzu na stanowiskach pracy w zakresie od 1/10 do 2 wartości najwyższego dopuszczalnego stężenia (NDS). Badania wykonano, stosując chromatograf gazowy (GC) z detektorem płomieniowo-jonizacyjnym (FID), wyposażony w kolumnę kapilarną Stabilwax (60 m x 0,32 mm, 0,5 μm). Metoda polega na: adsorpcji 2,2’-oksydietanolu na filtrze polipropylenowym, ekstrakcji metanolem i analizie chromatograficznej otrzymanego roztworu. Walidację metody przeprowadzono zgodnie z wymaganiami zawartymi w normie europejskiej PN-EN 482. Metoda umożliwia oznaczanie 2,2’-oksydietanolu w zakresie stężeń 1 ÷ 20 mg/m3 dla próbki powietrza o objętości 720 l. Uzyskano następujące parametry walidacyjne:- granica wykrywalności: 0,5 μg/ml - granica oznaczalności: 1,5 μg/ml - całkowita precyzja badania: 5,25% - względna niepewność całkowita: 11,5%. Opracowana metoda analityczna umożliwia selektywne oznaczanie 2,2’-oksydietanolu w powietrzu na stanowiskach pracy w stężeniach od 1 mg/m3, czyli od 1/10 wartości NDS w obecności innych alkoholi. Metoda charakteryzuje się dobrą precyzją i dokładnością, spełnia wymagania zawarte w normie europejskiej PN-EN 482 dla procedur oznaczania czynników chemicznych. Opracowaną metodę oznaczania 2,2’-oksydietanolu zapisano w postaci procedury analitycznej, którą zamieszczono w załączniku.

EN

2,2’-Oxydiethanol (DEG) is a colorless and oily liquid. 2,2’-Oxydiethanol is a by-product of ethylene glycol production. 2,2’-Oxydiethanol is used in the production of unsaturated polyester resins, plasticizers, acrylate and methacrylate resins, and urethanes. 2,2’-Oxydiethanol is a mild irritant. The aim of this study was to develop a method for determining concentrations of 2,2’-Oxydiethanol (inhalable fraction) in workplace air in the range from 1/10 to 2 MAC values. The study was performed using a gas chromatograph (GC) with a flame ionization detector (FID) equipped with a capillary column Stabilwax (60 m × 0.32 mm, 0.5 µm). This method is based on the adsorption of 2,2’-oxydiethanol on a polypropylene filter, extraction with methanol and chromatographic analysis of the obtained solution. The measurement range was from 1 to 20 mg/m3 for a 720-L air sample. Validation of the method was performed in accordance with Standard No. EN 482. The following validation parameters were determined: detection limit – 0.5 µg/ml, determination limit – 1.5 µg/ml, the overall accuracy of the method – 5.25%, the relative total uncertainty of the method – 11.5%. This analytical method enables selective determination of 2,2’-Oxydiethanol in workplace air in the presence of other alcohols at concentrations from 1 mg/m³ (1/10 MAC value). The method is precise, accurate and it meets the criteria for procedures for measuring chemical agents listed in Standard No. EN 482. The developed method of determining 2,2’-oxydiethanol has been recorded as an analytical procedure (see appendix).

3

The dependency on the temperature of efficiency of the regeneration process in glycols

Smulski R., Sacha J.

AGH Drilling, Oil, Gas

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2016

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Vol. 33, no. 4

733--746

EN

The water content of glycol is important from the perspective of the dehumidification quality of natural gas, as the greater is it’s content, the more adversely it will affect further absorption of glycol during the dehumidification process. In order to restore its original properties, sorption glycol undergoes regeneration that is the process which consists of thermal evaporation of water contained therein. The separation of these components is made possible by the evaporation of water at a lower temperature, compared to glycols. In the industrial practice of dehumidifying natural gas using the absorption method, four kinds of glycol can be used. Their characteristics are presented in the report, discussing the current methods of regeneration, as well as presenting results from the laboratory tests which consisted of water content measurements taken after evaporation of water from the glycol solutions. These results were summarized and compared. To determine the content of water, the Karl Fischer titration method was used.