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EN
Mexico has important kaolin deposits, which must be assessed to obtain products with a high commercial value, such as kaliophilite as raw material for biodiesel production. Two kaolins, A and B, with approximate SiO2:Al2O3 ratios of 1 and 1.2, respectively, were used as raw materials to produce kaliophilite. Both kaolins were obtained from the municipality of Agua Blanca in the State of Hidalgo, Mexico. Kaolins are a source of Al and Si for the synthesis of kaliophilite through an alkali fusion process at 700 °C followed by ultrasonic treatment at 28 kHz to different times and for Kaolin-KOH ratios of 1:1 and 1:1.2 (mass: mass). The kaolins as received and the alkaline mixtures heat and ultrasonically treated were analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). The most suitable kaolin for synthesizing kaliophilite was kaolin A with the Si/Al mass ratio of approximately 1, which exhibited a higher crystallinity index range from 54 to 79.6%. Higher KOH concentrations promote the amorphous material formation decreasing the kaliophilite amount. The crystallinity index was increased when the time of ultrasonic treatment was increased.
EN
Sludge treatment is one of the most difficult challenges for many industrial plants. In recent years, the use of ultrasound power has received considerable attention as one of the increasing tool for managing of this problem. Power ultrasound enhances chemical and physical changes in a liquid medium through the generation and subsequent destruction of cavitations bubbles. Therefore, the increased friction and stress in solution resultant with cleaning of the solid surfaces and dispersion of bonded/aggregated solid particles. In this study, the basic fundamentals of ultrasonic treatment and process variables were briefly overviewed. The study was also extended with preliminary analyses performed to determine its ability on the extraction of major and trace elements from Kırka Borax Concentrator tailings mainly boron as boric acid and Li as Li reach pregnant solution (PLS). Prior and after the sonification tests, physical, chemical and morphological analyses were carried out to determine the treatment performance. It was found that sonication leads the liberation of boron minerals from sludge and with the help of temperature they are dissolved and re-crystallized on clay substrate during cooling stage. The extraction test performed with these crystals revealed that Li-rich solution (that can be further use as source of lithium carbonate or lithium hydroxide production), and boric acid could be produced with easy and low cost beneficiation method.
EN
Ultrasonic treatment is known to be efficient for aluminium melt degassing with the additional benefits of being both economical and environment friendly. This paper describes the effect of ultrasonic degassing on the preparation of an AlSi9Cu3(Fe) alloy for High Pressure Die Casting (HPDC). The degassing efficiency was assessed in terms of the indirect evaluation of the melt, by means of the reduced pressure test and the porosity evaluation of the cast parts. Additionally, the corresponding hydrogen content was estimated with an experimental equation reported in the literature. Ultrasonic degassing shows greater efficiency in terms of hydrogen removal from the melt than conventional N2 + Ar lance bubbling. Components produced by HPDC without degassing, with ultrasonic degassing and with lance degassing, were analysed by computed tomography and by metallography. The results show that the components produced by HPDC after ultrasonic degassing have a similar porosity level to components degassed with conventional lance bubbling, both showing an important improvement over components produced without degassing treatment. Hardness values were similar for all different treatment conditions and well over the minimum value established for the alloy by the corresponding standard.
PL
Przedstawiono wyniki wpływu obróbki ultradźwiękowej na stabilność i aktywność antyoksydacyjną kwasu galusowego. Do badań wykorzystano cztery roztwory kwasu galusowego: o stężeniu 0,2 mg/mL i 1,0 mg/mL, sporządzone na bazie wody i metanolu. Obróbkę ultradźwiękową przeprowadzono, używając procesora ultradźwiękowego (Sonic VCX 750). Doświadczenie prowadzono przez 0, 10 i 30 min, wykorzystując pole akustyczne o częstotliwości 20 kHz oraz natężeniu 21 W/cm2 i 38 W/cm2. Nie stwierdzono statystycznie istotnego wpływu ultradźwięków na stabilność wodnych roztworów kwasu galusowego. Zaobserwowano nieznaczną, ale statystycznie istotną degradację metanolowych roztworów kwasu galusowego.
EN
Four gallic acid solns. (0.2 and 1.0 mg/mL) prepd. on the basis of H2O or MeOH were subjected to ultrasounds (frequency 20 kHz, intensity 21 or 38 W/cm2, time 0–30 min). A slight but statistically significant degrdn. of gallic acid was obsd. only for its MeOH solns., esp. for the concn. of 0.2 mg/mL and the treatment time of 30 min. Ultrasounds did not change the oxidative activity of the tested solns.
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PL
Praca dotyczy przygotowania lekkich pianobetonów z wykorzystaniem metody wstępnego spieniania. Trwałość pianobetonów o gęstości mniejszej niż 200 kg m-3 uzyskano zmniejszając stężenie środka spieniającego do 50% – 25% powszechnie stosowanego stężenia. Wyniki doświadczalne potwierdziły, że opóźniający hydratację cementu wpływ środka spieniającego można zrównoważyć zmniejszając jego stężenie. Taka metoda wraz z zastosowaniem szybkotwardniejącego cementu o dużej klasie wytrzymałości, zapewniała dobrą trwałość pianobetonów oraz ich wystarczającą wytrzymałość na ściskanie. Dzięki temu otrzymane pianobetony mogą być stosowane w praktyce.
EN
Present study deals with preparation of lightweight foam concretes using pre-formed foaming method. Stability of foam concretes with final bulk densities lower than 200 kg m-3 was attained by decreasing of FN1 concentration from 50% up to 25%, of the commonly used value. The experimental results have confirmed that retardation effect of foaming agent on cement hydration can be successfully suppressed by the decreasing of its concentration. This method together with the application of rapid hardening cement, belonging to higher strength class, ensured the good stability of prepared foam concretes and their sufficient compressive strength which makes them applicable in practice.
EN
This paper investigates breakage of calcite powder (d50 = 25.23 μm) to fine particle sizes using an ultrasonic generator (400 W, 24 kHz). The present study focuses on comminution of calcite powder in water media by ultrasonic treatment and the effect of some operational parameters such as treatment time (5–30 min), ultrasonic power (30-100% as amplitude), solid ratio (5-30% w/w), probe positions (0.5-2 cm) and cycle on the product size. Experimental results were evaluated on the basis of average particle size (d50). Sonication of calcite produced a drastic particle-size reduction (d50=12.89 μm) under optimal conditions.
EN
Liquid phase production technologies of metal matrix micro- and nanostructural composites are considered. Complex using magnetohydrodynamic stirring, ultrasonic treatment of melt during liquid and liquid-solid states and thixocasting advantages are proposed.
EN
The effect of ultrasonic treatment on two different waste activated sludges (WASI and WAS2) was compared by batch tests. WASI was taken from an industrial WWTP that treats pulp and paper wastewater, WAS2 was obtained from a traditional municipal WWTP. Physical and chemical characterization of sludges and supernatants was performed at various specific energy inputs. Upon increasing specific energy input, sludge structure changed, particle size decreased and organic and nitrogen release increased. A different release of organic matter and nitrogen compound related to the sludge origin was observed. The study is a preliminary assay of the potential of sonication treatment to enhance biogas production in anaerobic digestion.
EN
Purpose: Use of ultrasonic radiation for improving the properties of activated carbon was the aim of this paper. Increase of density of states at Fermi level was the main factor, responsible for working characteristics of electrochemical supercapacitors. Design/methodology/approach: Working parameters of supercapacitors on the base of activated carbon have been studied by means of precisional porometry, small angle X-ray scattering, cyclic voltamerometry, electrochemical impedance spectroscopy and computer simulation methods. Findings: The possibility to effect the interface between activated carbon and electrolyte by means of ultrasonic treatment in cavitation and noncavitation regimes is proved. It is shown that ultrasonic treatment in noncavitation regimes causes the significant increase of density of states at Fermi level that results in better farad-volt dependences. Research limitations/implications: This research is a complete and accomplished work. Practical implications: Modification of electric double layer by meanans in ultrasonic treatment, proposed in this work, could be regarded as effective way to obtaine the advanced electrode materials in devices of energy generation and storage. Originality/value: This work is important for physics, material science and chemistry because it is related with new possibilities to change the mobility of charge carries in electric double layer by means of ultrasonic irradiation.
EN
The effect of ultrasonic liquid metal treatment on the microstructure and the corrosion behaviour of the A356 Al-Si alloy was studied. The microstructures of the Al-Si were observed by means of optical and scanning electron microscopes. The corrosion behaviour was studied electrochemically and by gravimetric method. The results showed that the microstructure was modified from a coarse acicular plate-like form when no ultrasonic vibration was used, to a fi nely dispersed rosette-like form when ultrasonic treatment was employed. The ultrasonically treated samples showed higher resistance to pitting than the untreated sample. The soaking process negatively affected the pitting resistance.
PL
Badano wpływ ultradźwiękowej obróbki ciekłego metalu na mikrostrukturę i zachowanie korozyjne stopu A356 Al-Si. Mikrostruktury Al-Si obserwowano przy użyciu mikroskopu optycznego i elektronowego mikroskopu skaningowego. Zachowanie korozyjne badano metodami elektrochemicznymi i metodą grawimetryczną. Wyniki badań wykazały, że po obróbce ultradźwiękowej, mikrostruktura uległa przekształceniu z płaskich i szorstkich igiełek do postaci drobno rozproszonej w kształcie rozety. Próbki po obróbce ultradźwiękami wykazywały większą odporność na korozję wżerową niż próbki bez obróbki , natomiast moczenie odporność tę pogorszyło.
11
Content available remote Obróbka ultradźwiękowa ciekłej stali
PL
W pracy przedstawiono wyniki prób przemysłowych nadźwiękawiania ciekłej stali austenitycznej we wlewnicy.
EN
The paper presents results of ultrasonic processing industrial tests of liquid austenitic steel in ingot mould.
PL
W pracy przedstawiono wyniki wstępnej obróbki ultradźwiękowej miazgi marchwiowej. Celem przeprowadzonych doświadczeń było określenie wpływu pola akustycznego o częstotliwości 20 kHz na wydajność tłoczenia i zawartość suchej masy w uzyskanym soku. Badaniami objęto dwie odmiany marchwi: Nanda i Nevis. Miazgę podawano obróbce ultradźwiękowej przez czas od 0 do 15 minut. Otrzymane wyniki wskazują, że obróbka ultradźwiękowa przyczynia się do zwiększenia wydajności tłoczenia jak i zwiększonej ekstrakcji składników ciała stałego z miazgi marchwiowej.
EN
Paper presented the results of preliminary ultrasonic treatment of the carrot root pulp. The experiments aimed to determine the effect of acoustic field of 20 kHz frequency on juice extraction output and dry matter content in extracted juice. Carrot roots of two cultivars, Nanda and Nevis, were used as an experimental material. The carrot pulp was subjected to ultrasonic treatment for time ranging from 0 to 15 min. The experiments showed that the ultrasonic treatment resulted in increased extraction of solid components from the carrot pulp into juice.
PL
W ostatnich latach w coraz większym zakresie stosuje się ultradźwięki w technologii żywności. Wysoki stopień złożoności struktur biologicznych oraz przemian fizykochemicznych w polu ultradźwiękowym wciąż nie pozwala na jednoznaczny opis obserwowanych zjawisk. Celem pracy było wyznaczenie cech teksturalnych wybranych warzyw korzeniowych i określenie wpływu obróbki ultradźwiękowej na ich zmiany. Próbki kontrolne i po obróbce ultradźwiękowej poddano testowi podwójnego ściskania (TPA - deformacja 75%, V = 50 min/min.). Badania wykazały, że w warunkach eksperymentu obróbka ultradźwiękowa zasadniczo nie wpływa na zmiany teksturalne badanych warzyw.
EN
Within last years the ultrasounds are being applied in food processing to wider and wider extent. However, high level of biological structure complexity as well as the physico-chemical transformations occuring in ultrasonic field make an univocal description of observed phenomena still impossible. The study aimed at determination of textural properties for selected root vegetables and defining the effect of ultrasonic treatment on their changes. The samples both, control and after ultrasonic treatment, were subjected to double compression test (TPA - deformation 75%, V = 50 mm/min.). The results showed that under experimental conditions the ultrasonic treatment did not substantially affect the textural changes of tested vegetables.
EN
The influence of heat treatment and ultrasonic impact treatment on structure and properties of pearlite in surface layer of carburized steel are studied. The rolling friction tests have shown that the structural modification of surface layer leads to contact stability of a specimen.
PL
Zbadano wpływ obróbki cieplnej oraz ultradźwiękowej na strukturę oraz właściwości perlitu w warstwie wierzchniej. Badania w warunkach tarcia tocznego wykazały, że modyfikacja budowy warstwy wierzchniej zwiększa stabilność stykową próbek.
PL
W pracy przedstawiono porównanie wyników badań właściwości technologicznych mięsa wychładzanego dwiema metodami i dodatkowo obrabianego w polu ultradźwiękowym niskiej częstotliwości. W wyniku przeprowadzonych badań stwierdzono istotny wpływ metody wychładzania oraz zastosowanej obróbki ultradźwiękami na retencję wody przez mięso we wstępnej fazie po uboju.
EN
The paper presents the comparison of investigation results of processing properties of meat chilled by two methods and additionally treated in low ultrasonic frequency. The results of the carried out investigations show significant influence of the chilling method and the ultrasonic treatment on water retention of meat in the initial phase after the slaughter.
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