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1.
Study of ▫$Ni/Y_2O_3/polylactic$▫ acid composite
Tilen Švarc, Matej Zadravec, Žiga Jelen, Peter Majerič, Blaž Kamenik, Rebeka Rudolf, 2023, izvirni znanstveni članek

Opis: This study demonstrates the successful synthesis of Ni/Y2O3 nanocomposite particles through the application of ultrasound-assisted precipitation using the ultrasonic spray pyrolysis technique. They were collected in a water suspension with polyvinylpyrrolidone (PVP) as the stabiliser. The presence of the Y2O3 core and Ni shell was confirmed with transmission electron microscopy (TEM) and with electron diffraction. The TEM observations revealed the formation of round particles with an average diameter of 466 nm, while the lattice parameter on the Ni particle’s surface was measured to be 0.343 nm. The Ni/Y2O3 nanocomposite particle suspensions were lyophilized, to obtain a dried material that was suitable for embedding into a polylactic acid (PLA) matrix. The resulting PLA/Ni/Y2O3 composite material was extruded, and the injection was moulded successfully. Flexural testing of PLA/Ni/Y2O3 showed a slight average decrease (8.55%) in flexural strength and a small decrease from 3.7 to 3.3% strain at the break, when compared to the base PLA. These findings demonstrate the potential for utilising Ni/Y2O3 nanocomposite particles in injection moulding applications and warrant further exploration of their properties and new applications in various fields.
Ključne besede: ultrasound spray pyrolysis, Ni/Y2O3, lyophilization, PLA, extrusion, injection moulding
Objavljeno v DKUM: 05.04.2024; Ogledov: 69; Prenosov: 2
.pdf Celotno besedilo (3,29 MB)
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Contemporary approach to diagnostics in women with suspected pelvic endometriosis
Jure Knez, Andraž Dovnik, Maja Pakiž, Igor But, Milan Reljič, Vida Gavrić-Lovrec, Maja Banović, Iztok Takač, 2019, pregledni znanstveni članek

Ključne besede: endometriosis, endometrioma, ovarian cysts, deep pelvic endometriosis, ultrasound, pelvic pain
Objavljeno v DKUM: 27.03.2024; Ogledov: 73; Prenosov: 2
.pdf Celotno besedilo (225,42 KB)
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4.
Combination of lung ultrasound (a comet-tail sign) and N-terminal pro-brain natriuretic peptide in differentiating acute heart failure from chronic obstructive pulmonary disease and asthma as cause of acute dyspnea in prehospital emergency setting
Gregor Prosen, Petra Klemen, Matej Strnad, Štefek Grmec, 2011, izvirni znanstveni članek

Opis: Introduction: We studied the diagnostic accuracy of bedside lung ultrasound (the presence of a comet tail sign), N-terminal pro-brain natriuretic peptide (NT-proBNP), and clinical assessment (modified Boston criteria) in differentiating heart failure (HF)- related acute dyspnea from pulmonary (COPD/asthma) related acute dyspnea in the prehospital setting. Methods: Prospective study was performed at the Center for Emergency Medicine Maribor, Slovenia, between July 2007 and April 2010. Two groups of patients were compared: HF-related acute dyspnea group (n = 129) vs pulmonary-related (asthma/COPD) acute dyspnea group (n = 89). All patients underwent lung ultrasound examination, along with basic laboratory, rapid NT-proBNP testing and chest X-ray. Results: Ultrasound comet tail sign has 100% sensitivity, 95% specificity, 100% negative predictive value (NPV) and 96% positive predictive value (PPV) for the diagnosis of HF. NT-proBNP (cut-off point 1000 pg/ml) has 92% sensitivity, 89% specificity, 86% NPV and 90% PPV. Boston modified criteria have 85% sensitivity, 86% specificity, 80% NPV and 90% PPV. Comparing the three methods, we found significant differences between ultrasound sign vs NT-proBNP (P<0.05) and Boston modified criteria (P<0.05). Combination of ultrasound sign and NT-proBNP has 100% sensitivity, 100% specificity, 100% NPV and 100% PPV. With ultrasound we can exclude HF in patients with pulmonary related dyspnea who have positive NT-proBNP (> 1000 pg/ml) and previous history of HF. Conclusions: Ultrasound comet tail sign alone or in combination with NT-proBNP has a high diagnostic accuracy in differentiating between acute HF and COPD/asthma causes of acute dyspnea in prehospital emergency setting.
Ključne besede: lungs, ultrasound, N-terminal pro-brain natriuretic peptide, acute heart failure, chronic obstructive pulmonary disease, asthma, acute dyspnea
Objavljeno v DKUM: 29.06.2017; Ogledov: 1865; Prenosov: 389
.pdf Celotno besedilo (420,76 KB)
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5.
Programmable ultrasonic sensing system for targeted spraying in orchards
Denis Stajnko, Peter Berk, Mario Lešnik, Viktor Jejčič, Miran Lakota, Andrej Štrancar, Marko Hočevar, Jurij Rakun, 2012, izvirni znanstveni članek

Opis: This research demonstrates the basic elements of a prototype automated orchard sprayer which delivers pesticide spray selectively with respect to the characteristics of the targets. The density of an apple tree canopy was detected by PROWAVE 400EP250 ultrasound sensors controlled by a Cypress PSOC CY8C29466 microcontroller. The ultrasound signal was processed with an embedded computer built around a LPC1343 microcontroller and fed in real time to electro-magnetic valves which open/close spraying nozzles in relation to the canopy structure. The analysis focuses on the detection of appropriate thresholds on 15 cm ultrasound bands, which correspond to maximal response to tree density, and this was selected for accurate spraying guidance. Evaluationof the system was performed in an apple orchard by detecting deposits of tartrazine dye (TD) on apple leaves. The employment of programmable microcontrollers and electro-magnetic valves decreased the amountof spray delivered by up to 48.15%. In contrast, the reduction of TD wasonly up to 37.7% at some positions within the tree crown and 65.1% in the gaps between trees. For all these reasons, this concept of precise orchard spraying can contribute to a reduction of costs and environmental pollution, while obtaining similar or even better leaf deposits.
Ključne besede: air-assisted sprayer, ultrasound, algorithm, programmable, microcontroller, spray distribution, orchard
Objavljeno v DKUM: 22.06.2017; Ogledov: 2076; Prenosov: 463
.pdf Celotno besedilo (890,30 KB)
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Case study of the sonochemical decolouration of textile azo dye Reactive Black 5
Simona Vajnhandl, Alenka Majcen Le Marechal, 2007, izvirni znanstveni članek

Opis: The decolouration and mineralization of reactive dye C.I. Reactive Black 5, a well-known representative of non-biodegradable azo dyes, by means of ultrasonic irradiation at 20, 279 and 817 kHz has been investigated with emphasis on the effect of various parameters on decolouration and degradation efficiency. Characterization of the used ultrasound systems was performed using calorimetric measurements and oxidative species monitoring using Fricke and iodine dosimeter. Experiments were carried out with low frequency probe type, and a high-frequency plate type transducer at 50, 100 and 150 W of acoustic power and within the 5-300 mgžL initial dye concentration range. Decolouration, as well as radical production, increased with increasing frequency, acoustic power, and irradiation time. Any increase in initial dye concentration results in decreased decolouration rates. Sonochemical decolouration was substantially depressed by the addition of 2-methyl-2-propanol as a radical scavenger, which suggests radical-induced reactions in the solution. Acute toxicity to marine bacteria Vibrio fischeri was tested before and after ultrasound irradiation. Under the conditions employed in this study, no toxic compounds were detected after 6 h of irradiation. Mineralization of the dye was followed by TOC measurements. Relatively low degradation efficiency (50% after 6 h of treatment) indicates that ultrasound is rather inefficient in overall degradation, when used alone.
Ključne besede: textile industry, wastewater treatment, textile dyeing, reactive dyes, azo dyes, decoloration, ultrasound, degradation, decoloration kinetics, oxidizing species
Objavljeno v DKUM: 01.06.2012; Ogledov: 2092; Prenosov: 94
URL Povezava na celotno besedilo

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Ecological alternatives to the reduction and oxidation processes in dyeing with vat and sulphur dyes
Mojca Božič, Vanja Kokol, 2008, pregledni znanstveni članek

Opis: This article gives a summary of the most commonly used ecologically unfriendly processes for the reduction and oxidation of vat and sulphur dyes. It also describes the new alternatives that are in the development stage and could be important in the near future. Sodium dithionite as the dominant reducing agent produces large amounts of sodium sulphate, and also toxic sulphite and thiosulphate as by-products. Consequently, high amounts of hydrogen peroxide and alkali are required for the treatment of effluents, which add to the cost of the process. Attempts have been made to use organic biodegradable reducing agents, enzymes, catalytic hydrogenation, and also indirect or direct, electrochemical reductive methods that employ a redox mediator (electron-carrier). The reduction has also been carried out via the dye radical molecule or, in the case of indigo, by direct electrochemical reduction using graphite as the electrode material. Physical techniques, for example using ultrasound, magnetic fields or UV have been shown to be effective only when used to accelerate methods using classical reduction and oxidation processes. However, although these methods offer some environmental benefits, there is still no satisfactory alternative reducing and/or oxidising agent available today.
Ključne besede: textile dyeing, vat dyes, sulphur dyes, reduction, oxidation, catalysis, ecology, organic agents, electrochemistry, ultrasound, magnetic field, UV application, biotechnology
Objavljeno v DKUM: 01.06.2012; Ogledov: 2969; Prenosov: 115
URL Povezava na celotno besedilo

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The impact of ultrasonic-assisted dyeing on ecological parameters
Alenka Ojstršek, Darinka Fakin, 2008, objavljeni znanstveni prispevek na konferenci

Opis: The main contribution of our research was to compare the impact of the conventional dyeing process and the power ultrasonic technique on dye-bath exhaustion and, consequently, on dye-bath effluents during the dyeing of four dissimilar fabrics (cotton, viscose, wool and polyamide) using chemically-different dyestuffs (reactive, direct, acid and 1:1 metal complex) at two concentrations, regarding different operational parameters, in order toestimate the environmental impact of numerous parameters and dyeing systems.The efficiency of various dyeing procedures was verified by measuring on-line absorbance, followed by the calculation of exhaustion rate. After dyeing, the selected pollution parameters were monitored in dye-baths effluents, i.e. pH, total organic carbon (TOC), chemical oxygen demand (COD), and biochemical oxygen demand (BOD5). The obtained results indicated superior exhaustion of dyestuffs during ultrasound assistance in comparison to conventional dyeing, thus causing a reduction in dyeing time and energy consumption. Moreover, the selected pollution parameters were diminished in all the dye-baths effluents after ultrasonic dyeing, thus also enhancing environmental protection.
Ključne besede: exhaust dyeing, ultrasound, dye-bath effluents, colourimetry, pollution control
Objavljeno v DKUM: 31.05.2012; Ogledov: 1842; Prenosov: 27
URL Povezava na celotno besedilo

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