scholarly journals Qualitative extension of the EC′ Zone Diagram to a molecular catalyst for a multi-electron, multi-substrate electrochemical reaction

2016 ◽  
Vol 45 (24) ◽  
pp. 9970-9976 ◽  
Author(s):  
Daniel J. Martin ◽  
Brian D. McCarthy ◽  
Eric S. Rountree ◽  
Jillian L. Dempsey
Keyword(s):  
Acid Concentration ◽  
Catalyst Concentration ◽  
Electrochemical Reaction ◽  
Systematic Variation ◽  
Molecular Catalyst ◽  
Scan Rate ◽  
Zone Diagram

Traverse the EC′ Zone Diagram with a molecular H2-evolving electrocatalyst through systematic variation of the acid pKa, scan rate, acid concentration and catalyst concentration.

scholarly journals Produksi Asam Levulinat dari Inulin Umbi Dahlia (Dahlia sp. L) Menggunakan Katalis Asam Klorida

2017 ◽  
Vol 16 (2) ◽  
pp. 64
Author(s):  
Rosa Murwindra ◽  
Amilia Linggawati ◽  
Pepi Helza Yanti ◽  
Amir Awaluddin ◽  
Saryono '
Keyword(s):  
High Temperature ◽  
Acid Concentration ◽  
Levulinic Acid ◽  
Catalyst Concentration ◽  
Acid Catalyst ◽  
Reducing Sugar ◽  
Hot Water ◽  
Cool Temperature ◽  
Temperature Reaction ◽  
West Sumatra

Dahlia is a floriculture plant with tuber that rich of inulin. Inulin is soluble in hot water and it will settle on cool temperature in alcohol. Extraction of result from 100 g dahlia tuber taken from Bukittinggi, West Sumatra is 4% inulin (w/w dahlia tuber). Inulin flour produced is white gray. Qualitative tests with Seliwanoff and Nelson-Somogyi methods shows that inulin positive contained of fructose and reducing sugar. Extracted result of inulin can be converted into levulinic acid using acid catalyst at high temperature. In this experiment, production of levulinic acid will bundle with variate temperature, reaction time and catalyst concentration of hydrochloride acid. The reaction of inulin convertion was done in ampul that burned in oven. Conversion result of 5% inulin to be levulinic acid on heating 150 o C hydrochloride acid concentration 0,1 M about 25 minutes was 12,33% (w/w inulin). On heating 170 o C hydrochloride acid concentration 0,1 M about 15 minutes is 26,25% (w/w inulin), while on heating 150 o C hydrochloride acid concentration 1 M about 15 minutes is 32,28% (w/w inulin). Experiment result showed that concentration of glucose, levulinic acid and formiat acid increase with increasing in reaction reaction temperature while fructose concentration decrease from 55,14 mg/mL to be 0,12 mg/mL. The longer time reaction and the higher concentration of catalyst hydrochloride acid, the lower concentration of glucose and fructose and the larger concentration of levulinic acid and formic acid.

Modelling of Electrode Size Influence on Electrochemical MHD Processes

2021 ◽  
Vol 105 (1) ◽  
pp. 509-516
Author(s):  
Martin Mačák ◽  
Petr Vyroubal
Keyword(s):  
Magnetic Field ◽  
Electrochemical Reaction ◽  
Microfluidic Devices ◽  
Ansys Fluent ◽  
Electrode Size ◽  
Scan Rate ◽  
Current Densities ◽  
Control Fluid ◽  
The Magnetic Field ◽  
Mixing And Transport

The presented article describes a simulation of an electrochemical reaction in a presence of a magnetic field using a custom model implemented into Ansys Fluent. The influence of electrode size and the effect of scan rate is investigated further. The results show that the magnetic field can significantly increase mixing and transport of species towards the electrode, which results in higher obtained current densities. Additionally, this method can be used to control fluid flow in microfluidic devices.

scholarly journals Organic acid-assisted catalytic wet torrefaction of oil palm trunks (OPT)

2021 ◽  
Vol 1195 (1) ◽  
pp. 012024
Author(s):  
M Soh ◽  
J J Chew ◽  
J Sunarso
Keyword(s):  
Citric Acid ◽  
Formic Acid ◽  
Acid Concentration ◽  
Residence Time ◽  
Oil Palm ◽  
Catalyst Concentration ◽  
Deionized Water ◽  
Fuel Properties ◽  
Energy Yield ◽  
Yield Value

Abstract Oil palm trunks (OPT) are attractive bio-fuel sources given their abundant availability. Nonetheless, the inherent properties of these biomass can lead to their inefficient use as bio-fuel directly. This work utilizes four organic acids (i.e., acetic, formic, levulinic, and citric acid) as catalyst in wet torrefaction to enhance the fuel properties of OPT hydrochar. In this study, the effects of different catalysts, catalyst concentrations, and residence times on the fuel properties of OPT hydrochar are analyzed. To study the effect of residence time, 0.2M of acid concentration was used for all four acids at 220 °C for 3 hr and 24 hr. Meanwhile, study on the effect of catalyst concentration was performed at 220 °C for 24 hr at 0.2M and 1.0M for all four acids. Increasing the residence time decreased the solid yield of OPT hydrochar treated in deionized water, acetic, formic, and levulinic acid, while wet torrefaction in citric acid results in close solid yield value in both residence time. The energy yield was observed to decrease in all liquid medium with increasing residence time except for formic acid and citric acid. On the other hand, increasing the acid concentration increased the OPT hydrochar solid yield in all acids except formic acid and the highest energy yield of 77.08% was obtained from wet torrefaction in 1.0M of citric acid at 220 °C for 24 hr. In summary, citric acid is an environmentally friendly acid to be used as catalyst to enhance the fuel properties of OPT hydrochar. Further study on the reaction mechanisms that governs such fuel properties enhancement with citric acid is warranted.

The Effect of Stress and Warfarin on the Adrenal Gland in Relation to Spontaneous Hemorrhage, as Judged by Measurement of Adrenal Ascorbic Acid and Serum Corticosterone

1971 ◽  
Vol 26 (02) ◽  
pp. 275-288 ◽  
Author(s):  
S Chattopadhyay ◽  
D. D Johnson ◽  
G. J Millar ◽  
L. B Jaques
Keyword(s):  
Ascorbic Acid ◽  
Acid Concentration ◽  
Ascorbic Acid Concentration ◽  
Corticosterone Concentration ◽  
Serum Corticosterone ◽  
Spontaneous Hemorrhage ◽  
Combined Action ◽  
Series Of Experiments ◽  
Pituitary Adrenal Axis

SummaryRats were subjected to the following procedures: No treatment, Stressor (10% NaCl i.p.), Warfarin for 7 days, Stressor followed by Warfarin; and groups were sacrificed at intervals for assessment of spontaneous hemorrhage and of adrenal ascorbic acid concentration. There was no hemorrhage in the no treatment and stressor groups; some hemorrhage in the warfarin group; profound hemorrhage with Warfarin + Stressor. The adrenal ascorbic acid concentration was found to be lower, 8 h and again 5 days after stress, and remained lower in the warfarin + stress animals. Warfarin had no effect on adrenal ascorbic acid level.In another series of experiments in which the stress consisted of an electric current to the cage floor for 6 sec over 15 min, rats were sacrificed daily for determination of serum corticosterone concentration and occurrence of spontaneous hemorrhage. There was a statistically significant increase of serum corticosterone concentration with stress, warfarin and combined warfarin and stress treatments (P< 0.001 for all three variables). There was a significant correlation (r = 0.96 and 0.89, P< 0.01) for serum corticosterone concentration with hemorrhage score and incidence of hemorrhage in stressed rats receiving warfarin, but not in those receiving only warfarin. The results indicate an activation, rather than an exhaustion, of the pituitary-adrenal axis during the combined action of anticoagulant and stress, which results in the development of spontaneous hemorrhage.

Pb Electrodeposition in the Presence of Chlorine Ions on Cu(100): An in Situ Optical Reflectivity Difference Study

2003 ◽  
Vol 781 ◽  
Author(s):  
J. Gray ◽  
W. Schwarzacher ◽  
X.D. Zhu
Keyword(s):  
Oblique Incidence ◽  
Opposite Sign ◽  
Bulk Phase ◽  
Phase Layer ◽  
Optical Reflectivity ◽  
Scan Rate ◽  
Different Types ◽  
Chlorine Ions ◽  
High Overpotentials

AbstractWe studied the initial stages of the electrodeposition of Pb in the presence of chlorine ions on Cu(100), using an oblique-incidence optical reflectivity difference (OIRD) technique. The OI-RD results reveal that immediately following the underpotential deposition (UPD) of the first Pb monolayer, two different types of bulk-phase films grow depending upon the magnitude of overpotential and cyclic voltammetry (CV) scan rate. At low overpotentials and/or slow scan rates, we propose that a bulk-phase Pb film grows on top of the UPD monolayer. At high overpotentials and/or fast scan rates, either a PbO, PbCl2, or a rough Pb bulk-phase layer grows on top of the UPD layer such that the reflectivity difference signal from such a film has an opposite sign.

Systematic variation and differences in insulin-autoantibody measurements

Diabetes ◽  
1989 ◽  
Vol 38 (2) ◽  
pp. 172-181 ◽  
Author(s):  
T. J. Wilkin ◽  
S. L. Schoenfeld ◽  
J. L. Diaz ◽  
V. Kruse ◽  
E. Bonifacio ◽  
...  
Keyword(s):  
Systematic Variation ◽  
Insulin Autoantibody

PEMBUATAN SURFAKTAN DARI ASAM OLEAT

2019 ◽  
Vol 1 (3) ◽  
pp. 68
Author(s):  
Puguh Setyopratomo ◽  
Edy Purwanto ◽  
H. Yefrico ◽  
H. Yefrico
Keyword(s):  
Oleic Acid ◽  
Optimum Condition ◽  
Reaction Temperature ◽  
Catalyst Concentration ◽  
Acid Number ◽  
Esterification Reaction ◽  
Number Density ◽  
Sample Analysis ◽  
Reaction Conversion ◽  
Glycerol Mono

The synthesis of glycerol mono oleic from oleic acid and glycerol is classified as an esterification reaction. This research is aimed to study the influent of reaction temperature and catalyst concentration on reaction conversion. During the experiment the temperature of reaction mixture was varied as 110 oC, 130 oC, and 150 oC, while the catalyst concentration of 1%, 3 %, and 5% was used. The batch experiment was conducted in a glass reactor equipped with termometer, agitator, and reflux condensor. The oleic acid – glycerol mol ratio of 1 : 2 was used as a mixture feed. To maintain the reaction temperature at certain level, the oil bath was used. After the temperature of reaction mixture was reached the expected value, then H2SO4 catalyst was added to the reactor.  To measure the extent of the reaction, every 30 minutes the sample was drawn out from the reactor vessel. The sample analysis include acid number, density, and viscosity measurement. From this research the optimum condition which is the temperature of reaction of 150 oC and 1% catalyst concentration was obtained. At this optimum condition the convertion reach 86% and the analysis of other physical properties of the product show the acid number of 24.12, the density of 0.922 g/cc, and the viscosity of 118.4 cp.

Pengaruh Jenis Co-Solvent terhadap Rendemen dan Mutu Biodiesel secara Transesterifikasi In Situ Menggunakan Radiasi Gelombang Mikro

2016 ◽  
Vol 10 (2) ◽  
pp. 119-126
Author(s):  
Mahlinda Mahlinda ◽  
Fitriana Djafar
Keyword(s):  
Catalyst Concentration ◽  
Maximum Yield ◽  
Acid Value ◽  
Experimental Result ◽  
In Situ Transesterification ◽  
Yield And Quality ◽  
Solvent Type ◽  
Biodiesel Quality

The main purpose of this research was to observer effect co-solvent type (n-Hexane, chloroform and without co-solvent)  toward yield and quality of biodiesel via in situ transesterification process using microwave irradiation. The process was studied at microwave power 450 watt, reaction time 4 minutes, methanol to seed ratio 25:1 and catalyst concentration 5%. The physicochemical parameters of the biodiesel produced such as viscosity, density and acid value were analysed and compared with the SNI 7182-2012 standard. The experimental result showed the maximum yield biodiesel 78,32% obtained by using co-solvent chloroform.Test result of physicochemical properties (viscosity, density and acid value) of biodiesel products using co solvent n-Hexane, chloroform and without co solvent showed that these products conform to the SNI 7182-2012 standars. The type of co-solvent only affectedon biodiesel yield dan not affected on biodiesel quality (viscosity, density and acid value).  ABSTRAKTujuan penelitian ini adalah untuk mempelajari pengaruh jenis co-solvent (n-Hexane, chloroform dan tanpa co-solvent) terhadap rendemen dan mutu biodiesel secara trasesterifikasi in situ menggunakan radiasi gelombang mikro. Proses dilakukan pada daya gelombang mikro 450 watt, waktu reaksi 4 menit, perbandingan berat metanol terhadap bahan baku 25:1 dan jumlah katalis 5%. Parameter fisiko kimia dari produk biodiesel seperti viskositas, densitas dan angka asam di analisa dan dibandingkan dengan standar SNI 7182-2012 tentang biodiesel. Hasil penelitian menunjukkan rendemen maksimum biodiesel sebesar 78,32% diperoleh dengan menggunakan co-solvent chloroform. Hasil pengujian  karakteristik fisiko kimia (viskositas, densitas dan angka asam) dari produk biodiesel menggunakan co-solvent n-Hexane, chloroform dan tanpa co-solvent menunjukkan bahwa semua parameter ini masih memenuhi standar SNI 1782-2012 tentang biodiesel. Jenis co-solvent hanya berpengaruh pada rendemen biodiesel dan tidak berpengaruh terhadap mutu biodiesel (viskositas, densitas dan bilangan asam).Kata kunci: co-solvent, in situ transesterifikasi, microwave, rendemen, mutu   

Electromigration and Electrochemical Reaction Mixed Failure Mechanism in Gold Interconnection System

1999 ◽  
Author(s):  
Hide Murayama ◽  
Makoto Yamazaki ◽  
Shigeru Nakajima
Keyword(s):  
Failure Mechanism ◽  
Failure Rate ◽  
Electrochemical Reaction ◽  
Dielectric Films ◽  
Failure Rates ◽  
Interlayer Dielectric ◽  
Bipolar Devices ◽  
Gold Metallization

Abstract Power bipolar devices with gold metallization experience high failure rates. The failures are characterized as shorts, detected during LSI testing at burn-in. Many of these shorted locations are the same for the failed devices. From a statistical lot analysis, it is found that the short failure rate is higher for devices with thinner interlayer dielectric films. Based upon these results, a new electromigration and electrochemical reaction mixed failure mechanism is proposed for the failure.

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