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Volume 5, Year 2014, Issue 3, July-September

The Automatic Recognition of Isolated Sign Language Signs Based on Gesture Components and DTW Algorithm
Author:
Katarzyna Barczewska
Downloads:
32 x
 

Abstract: Author presents sign language features that can provide the basis of the sign language automatic recognition systems. Using parameters like position, velocity, angular orientation, fingers bending and the conventional or derivative dynamic time warping algorithms classification of 95 signs from the AUSLAN database was performed. Depending on the number of parameters used in classification different accuracy values were obtained (defined as the ratio of correctly recognized gestures to all gestures from test set), with the highest value 87.7% for the case of classification based on all the features and the derivative dynamic time warping method. 

Keywords: automatic gesture recognition, sign language, DTW, DDTW

Area: Biomedical Engineering

Comparison of scanning strategies for the Small Mobile Mapping System
Author:
Karol Majek, Janusz Będkowski
Downloads:
10 x
 

Abstract:  In this paper two scanning strategies (stop-scan, continuous scanning) of Small Mobile Mapping System (SMMS) are discussed. SMMS registers 3D scans to provide accurate metric maps. This strategies have been implemented and evaluated in INDOOR environment. First is stop-scan fashion – SMMS stops, acquires data and moves forward to next position. The second approach is scan acquisition during motion. The data acquired in these approaches are registered using GPGPU ICP algorithm. As a result the comparison of the two registered point clouds with ground truth data is demonstrated.

Keywords: 3D scan matching, GPGPU ICP algorithm, Mobile Mapping System

Area: Mechanics, Automatics and Robotics

Resistojet thruster with a power system based on supercapacitors
Author:
Lukasz Mezyk, Arkadiusz Kobiera, Lukasz Boruc, Piotr Biczel, Piotr Wolanski
Downloads:
19 x
 

Abstract:  This paper presents research into a resistojet model that can be powered by supercapacitors for satellite propulsion applications. The performance of the system, calculated including a preliminary study of mass and power budget, shows that this solution has potential for a certain range of space missions. The main problem when designing a pulsed resistojet is the compromise between the thermal capacity of the resistojet and the heat transfer efficiency of the device. When the heater is used in pulsed mode, it should have low mass and thermal capacity in order to reduce the energy required to heat the devices. On the other hand, the main technical restriction in resistojet thrusters is heat transfer due to the laminar regime of the flow in the heater. The heat transfer area should be as large as possible, but the mass of the device limits any such increase in area. In this research several design options were considered in an attempt to find the optimal solution. After research on the oscillating element and porous heater, capillary tubes directly heated by the current were determined to be the most effective solution. A power supply based on supercapacitors was constructed. It consists of 30 supercapacitors of 300 F each, connected to deliver 70 V of voltage, 10F of total capacitance and maximum peak power of 5 kW. Research for three different gases – ammonia, propane and butane – was conducted and the results are presented in this paper.

Keywords: resistojet, thruster, satellite

Area: Mechanics, Automatics and Robotics

Mass spectrometric detection of products of decarboxy-betanins UV-irradiation
Author:
Karolina Starzak, Anna Skopińska, Dominika Szot, Sławomir Wybraniec
Downloads:
14 x
 

Abstract:  Betalains are a group of natural plant pigments, responsible for red-violet colour of numerous flowers, fruits and roots. They commonly occur in order of Caryophyllales (Caryophyllales). Recent studies revealed great health promoting properties of these pigments, but their natural origin make them very labile under various physicochemical conditions. In the case of betanin degradation, many new, decarboxy-betanins are formed. Latest study showed that UV-irradiation had significant impact on betanin stability, however, no deeper studies were performed in this field. In order to know an impact of the process conditions on degradation of betanin and its decarboxylated derivatives, series of experiments with UV-photo-irradiation was performed in aqueous solutions as well as in various organic solvents at wide range of pH. The highest pigment stability was observed in aqueous solutions for betanin and 17-decarboxybetanin at pH 4.5–7, and for 2,17-didecarboxybetanin at low pH. In all investigated organic solutions, all of the studied compounds have been degraded. The LC-DAD-ESI-MS analysis identified new reaction products. The results showed that UV-photo-irradiation leads mainly to a formation of many new and various 14,15-dehydrobetanins.

Area: Chemistry and Pharmacy

Semi-synthesis of red beet betacyanin ethyl-esters by esterification
Author:
Dorota Tuwalska, Karolina Starzak, Dominika Szot, Sławomir Wybraniec, Peter Winterhalter, Gerold Jerz
Downloads:
14 x
 

 Abstract:  Red beet pigments recovered from Beta vulgaris L. (Chenopodiaceae), mainly consist of purple betacyanins, such as 15R/15S-betanin. Currently,this pigment class is intensively investigated in respect of stability in food systems. Quite popular is the use of red beet extracts in dairy products such as yoghurts, and ice-creams. So far, there are no issues of toxicity using these natural pigments in food – so they seem to be a very good alternative to replace synthetic dyes which had been frequently discussed for negative side-effects to human health. Betacyanins, the glycosidation products of betanidin are very polar and therefore water soluble pigments, which are biosynthetically derived from condensation of cyclo-DOPA and betalamic acid. The significant polarity of betacyanins requires the use of ion-pair reagents such as trifluoro-acetic acid (TFA) or other homologue fluorinated additives under standard separation conditions on larger scale in spiral coil countercurrent chromatography (spCCC). In our synthetic experiment, the polarity of the natural betacyanins was reduced. This omitted the use of toxic per-fluoro ion-pair reagents. The three carboxylic groups of the betanin pigment backbone were the target functional groups of the derivatisation. In semi-synthesis, fortified red beet pigment extract was esterified with water-free ethanolic hydrogen chloride solution. The reaction was carried out at ambient temperature (7 days) to yield a mixture of betacyanin mono-, di- and tri-ethyl-esters, and their epimeric forms, as well as the respective betanidin-ethyl-esters. The time course of the reaction mixture was monitored by analytical C18-HPLC with ESI-DAD-MS/MS detection. The detected molecular weights of the pigments confirmed the presence of expected products. To the best of our knowledge, the presence of betalains containing ethyl-ester groups in biological samples have not been studied before.

Keywords: betacyanin ethyl-esters, betalains, betacyanins, betanin, betanidin, esterification

Area: Chemistry and Pharmacy

Thermal degradation of 17-decarboxy-betanin monitored by LC-MS
Author:
Dominika Szot, Karolina Starzak, Anna Skopińska, Dorota Tuwalska, Sławomir Wybraniec
Downloads:
13 x
 

 Abstract:   A thermal stability study on 17-decarboxy-betanin depending on physicochemical process conditions was conducted. 17-decarboxy-betanin is one of betacyanin, natural origin pigments applied in food and pharmaceutical industry instead of artificial colorants. There is a need for searching of new non-toxic natural food components and this is a reason of increasing interest of betacyanins. As most derivatives of betanin obtained by decarboxylation, 17-decarboxy-betanin tends to degrade in the presence of some factors such as increased temperature or other conditions of the reaction environment [1]. This subject was investigated in this study because the stability of the pigments is still a significant issue limiting their wide application. The degradation of 17-decarboxy-betanin during heating in selected solutions: water as well as aqueous solutions of ethanol 50% (v/v), methanol 50% (v/v) and acetonitrile 50% (v/v) at pH in the range 3-8 was tested. As UV-Vis spectra indicate, 17-decarboxy-betanin tends to degrade mostly at pH 3, notwithstanding a type of solution. The products of degradation were identified by LC-DAD-ESI-MS. As a result of incubation at 85°C in different solutions, various mono-, bi- and tridecarboxylated as well as dehydrogenated derivatives were obtained. The dominant product of 17-de-carboxy-betanin degradation is 2,15,17-tridecarboxy-2,3-dehydro-betanin. 

Keywords: 17-decarboxy-betanin , betacyanins, thermal degradation

Area: Chemistry and Pharmacy

Reactions of decarboxylated betanins under influence of halogen light
Author:
Anna Skopinska, Dominika Szot, Karolina Starzak, Sławomir Wybraniec
Downloads:
17 x
 

 Abstract:   Betalains as natural plant pigments are very sensitive to several factors, including light, therefore, studies on stability of their derivatives which retain their attractive color, are crucial for their potential application in pharmaceutical, food or cosmetic industries. An effect of irradiation by halogen light on reactivity of main decarboxylated derivatives of betacyanins (2-decarboxy-betanin, 17-decarboxy-betanin and 2,17-decarboxy-betanin) was investigated in aqueous and organic-aqueous solutions: 50% (v/v) acetonitrile, 50% (v/v) methanol and 50% (v/v) ethanol, at pH range 3-8. The double decarboxylation of betanin (at C-2 and C-17 position of carbon) significantly increases the stability of this pigment in the acidic media. As a result of pigments reactions induced by light, some betacyanin derivatives with different decarboxylation and dehydrogenation levels were identified by chromatography with tandem mass spectrometry (LC-MS/MS) and diode array detection (LC-DAD).

Keywords: betanin, decarboxylated betacyanins, photolability, mass spectrometry

Area: Chemistry and Pharmacy

 
 
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