Microwave plasma discharges for biomass pretreatment: Degradation of a sodium carboxymethyl cellulose model

Biogas production is an important component of an environmentally benign renewable energy strategy. However, the cost-effectiveness of biogas production from biomass is limited by the presence of polymeric structures, which are recalcitrant to digestion by bacteria. Therefore, pretreatments must often be applied prior to anaerobic fermentation to increase yields of biogas. Many physico-chemical pretreatments have a high energy demand and are generally costly. An alternative could be the ignition of a plasma directly in the biomass substrate. The reactive species that are generated by plasma-liquid interactions, such as hydroxyl radicals and hydrogen peroxides, could contribute significantly to the disintegration of cell walls and the breakage of poorly digestible polymers. With respect to economic, processing, and other potential benefits, a microwave instigated and sustained plasma was investigated. A microwave circuit transmitted 2-kW pulses into a recirculated sodium carboxymethyl cellulose solution, which mimicked the rheological properties of biomass. Each microwave pulse had a duration of 12.5 ms and caused the ignition of a discharge after a vapor bubble had formed. Microwaves were absorbed in the process with an efficiency of ∼97%. Slow-motion imaging showed the development of the discharge. The plasma discharges provoked a decrease in the viscosity, probably caused by the shortening of polymer chains of the cellulose derivative. The decrease in viscosity by itself could reduce processing costs and promotes bacterial activity in actual biomass. The results demonstrate the potential of microwave in-liquid plasma discharges for the pretreatment of biomass. © 2020 Author(s)

Power grip, pinch grip, manual muscle testing or thenar atrophy - which should be assessed as a motor outcome after carpal tunnel decompression? A systematic review

<p>Abstract</p> <p>Background</p> <p>Objective assessment of motor function is frequently used to evaluate outcome after surgical treatment of carpal tunnel syndrome (CTS). However a range of outcome measures are used and there appears to be no consensus on which measure of motor function effectively captures change. The purpose of this systematic review was to identify the methods used to assess motor function in randomized controlled trials of surgical interventions for CTS. A secondary aim was to evaluate which instruments reflect clinical change and are psychometrically robust.</p> <p>Methods</p> <p>The bibliographic databases Medline, AMED and CINAHL were searched for randomized controlled trials of surgical interventions for CTS. Data on instruments used, methods of assessment and results of tests of motor function was extracted by two independent reviewers.</p> <p>Results</p> <p>Twenty-two studies were retrieved which included performance based assessments of motor function. Nineteen studies assessed power grip dynamometry, fourteen studies used both power and pinch grip dynamometry, eight used manual muscle testing and five assessed the presence or absence of thenar atrophy. Several studies used multiple tests of motor function. Two studies included both power and pinch strength and reported descriptive statistics enabling calculation of effect sizes to compare the relative responsiveness of grip and pinch strength within study samples. The study findings suggest that tip pinch is more responsive than lateral pinch or power grip up to 12 weeks following surgery for CTS.</p> <p>Conclusion</p> <p>Although used most frequently and known to be reliable, power and key pinch dynamometry are not the most valid or responsive tools for assessing motor outcome up to 12 weeks following surgery for CTS. Tip pinch dynamometry more specifically targets the thenar musculature and appears to be more responsive. Manual muscle testing, which in theory is most specific to the thenar musculature, may be more sensitive if assessed using a hand held dynamometer – the Rotterdam Intrinsic Handheld Myometer. However further research is needed to evaluate its reliability and responsiveness and establish the most efficient and psychometrically robust method of evaluating motor function following surgery for CTS.</p

Влияние плазмонных наночастиц на характеристики плазмоактивированных фотокатализаторов / Н. А. Савастенко, Ф. Брюзер, В. А. Люшкевич

Энергоэффективные технологии и энергетический менеджментEnergy efficient plasma technologies have been successfully applied for decades in the field of material processing. In particular, low-temperature plasma has been used for catalyst synthesis. It was shown that impregnation with plasmonic silver (Ag) nanoparticles (NPs) improved the activity of plasma treated catalysts. In this study, the influence of Ag NPs was investigated on the optical characteristics of the plasma treated photocatalysts. Zinc oxide (ZnO) was chosen as a photocatalyst. The plasma treatment was performed in dielectric barrier discharge (DBD) plasma. The catalysts were characterized by photoluminescence (PL). The UV-VIS spectroscopy was used to measure the optical band gap.This work was partially financially supported by the Belorussian Republican Foundation for Fundamental Research (grant No F17-076)Энергоэффективные плазменные технологии уже в течение нескольких десятилетий успешно применяются для обработки материалов. В частности, низкотемпературная плазма применяется для синтеза катализаторов. Было показано, что импрегнирование плазмонными наночастицами (НЧ) серебра (Ag) повышает активность катализаторов, обработанных в плазме. В настоящей работе исследовано влияние наночастиц серебра на оптические характеристики фотокатализаторов. Оксид цинка (ZnO) был выбран в качестве фотокатализатора. Плазма диэлектрического барьерного разряда (ДБР) была использована для обработки катализаторов. Катализаторы были исследованы методом фотолюминесценции (ФЛ). Для определения ширины запрещенной зоны применялась спектроскопия в УФ и видимой области

Влияние плазмонных наночастиц на характеристики плазмоактивированных фотокатализаторов / Н. А. Савастенко, Ф. Брюзер, В. А. Люшкевич

Энергоэффективные технологии и энергетический менеджментEnergy efficient plasma technologies have been successfully applied for decades in the field of material processing. In particular, low-temperature plasma has been used for catalyst synthesis. It was shown that impregnation with plasmonic silver (Ag) nanoparticles (NPs) improved the activity of plasma treated catalysts. In this study, the influence of Ag NPs was investigated on the optical characteristics of the plasma treated photocatalysts. Zinc oxide (ZnO) was chosen as a photocatalyst. The plasma treatment was performed in dielectric barrier discharge (DBD) plasma. The catalysts were characterized by photoluminescence (PL). The UV-VIS spectroscopy was used to measure the optical band gap.This work was partially financially supported by the Belorussian Republican Foundation for Fundamental Research (grant No F17-076)Энергоэффективные плазменные технологии уже в течение нескольких десятилетий успешно применяются для обработки материалов. В частности, низкотемпературная плазма применяется для синтеза катализаторов. Было показано, что импрегнирование плазмонными наночастицами (НЧ) серебра (Ag) повышает активность катализаторов, обработанных в плазме. В настоящей работе исследовано влияние наночастиц серебра на оптические характеристики фотокатализаторов. Оксид цинка (ZnO) был выбран в качестве фотокатализатора. Плазма диэлектрического барьерного разряда (ДБР) была использована для обработки катализаторов. Катализаторы были исследованы методом фотолюминесценции (ФЛ). Для определения ширины запрещенной зоны применялась спектроскопия в УФ и видимой области

Повышение фотокаталитической активности TiO2 плазменными методами / Н. А. Савастенко, Ф. Брюзер, С. А. Маскевич

Энергоэффективные технологии и энергетический менеджментРlasma-assisted methods were applied to enhance the activity of TiO2 -based photocatalysts. A radio frequency (RF)-plasma was applied to treat the bare and Ru dye-sensitised TiO2 nanopowders (anatase) to enhance their photocatalytic activity. Plasma treatment was performed either in inert or in reactive atmosphere. In latter case, the plasma treatment resulted in covering the catalysts with a polymer layer. The photocatalytic activities of catalysts were evaluated by measuring the photodegradation of methyl orange (MO) in aqueous solution exposed to ultraviolet (UV) light. The MO concentration in solution was measured spectrophotometrically (UV-Vis spectrophotometry). The photocatalytic activity expressed in term of rate constant was 2.6 times higher for TiO2 covered with a polymer layer than that for bare titania. A decrease in activity was observed after RF-plasma treatment of bareTiO2.This work was partially financially supported by the Belorussian Republican Foundation for Fundamental Research (grant No F17-076)Для усиления фотокаталитической активности катализаторов на основе TiO2 были использованы плазменные методы. Плазма высокочастотного разряда использовалась для отбработки наноразмерного порошка TiO2 (анатаз) до и после сенситизации красителем на основе Ru. Плазменная обработка проводилась как в инертной, так и в реакционной атмосфере. В последнем случае в результате плазменной обработки на поверхность катализатора наносились полимерные пленки. Фотокаталитическую активность исследовали в реакции фотодеградации метилового оранжевого (МО) в водном растворе при облучении ультрафиолетовым (УФ) излучением. Концентрацию МО определяли спетрофотометрически. Константа реакции фотодеградации МО в присутствии TiO 2 , поктрытого полимерной пленкой, была в 2,6 раз выше константы реакции в присутствии необработанного оксида титана. Плазменная обработка TiO 2 снижала его активность

Electrocatalysts for oxygen reduction prepared by plasma treatment of carbon supported cobalt tetramethoxyphenylporphyrin

Heat treated cobalt tetramethoxyphenylporphyrin CoTMPP on carbon support Black Pearls is well known as highly active material for the electroreduction of oxygen in acidic electrolytes. However, in the process of catalyst formation at high temperatures aggregation of the carbon supported particles occurs causing a detrimental decrease of the active surface. This contribution describes for the first time an alternative preparation method for a CoTMPP based electrocatalyst via low temperature plasma treatment suppressing particle aggregation. Different parameters of plasma duration of treatment, power, gas composition have been varied in order to investigate their influence on the preparation process. After treatment, the electrochemical activity of the samples has been tested by Rotating Disc Electrode technique RDE and Cyclovoltammetry CV . Their structural features were characterised by UV VIS and IR spectroscopy. A comparison of the results with Argon plasma treated carbon supported CoTMPP catalyst reveals higher electrochemical activity as with heat treated sample. The investigations open up new preparation strategies using the special features of plasma technology for surface optimised catalytic material

Comparative study of the carbonisation of CoTMPP by low temperature plasma and by heat treatment

Low temperature plasma treatment LTP of cobalt tetramethoxyphenylporphyrin CoTMPP has been applied as a promising alternative method to the conventional heat treatment in order to attain high active catalysts for the electroreduction of oxygen. In this contribution it is shown that CoTMPP can be completely transformed into a carbon matrix by adjusting adequate LTP parameters. The carbonisation process of CoTMPP is investigated at different operation conditions by Raman and IR spectroscopy and compared with the structural features of the heat treated one. As a result it appears that the LTP occurs via a different carbonisation process which yields in a more homogeneous defined molecular carbon structur

Plasma modification of catalysts for cathode reduction of hydrogen peroxide in fuel cells

Plasma techniques have been extensively utilized in catalysis. Catalyst preparation using plasma treatment allows improving dispersion, enhancing catalyst performance and stability. In this paper, the low pressure RF discharge is shown as an efficient method to enhance activity of Co based electrocatalyst for the reduction of hydrogen peroxide. It was found 20 CoTMPP C catalyst treated by plasma presents 2 fold higher catalytic activity than catalyst prepared by without plasma treatment. The influence of catalyst treatment on elemental surface and bulk concentration and performance of catalysts for hydrogen peroxide in a fuel cell was investigate