scholarly journals Estimation of Potential Distribution during Crevice Corrosion through Analysis of I–V Curves Obtained by LAPS

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2873
Author(s):  
Kiyomi Nose ◽  
Ko-ichiro Miyamoto ◽  
Tatsuo Yoshinobu
Keyword(s):  
Crevice Corrosion ◽  
Potential Distribution ◽  
Corrosion Current ◽  
Experimental Methods ◽  
Narrow Gap ◽  
Anodic Current ◽  
Ph Change ◽  
Ir Drop ◽  
A Value ◽  
Light Addressable Potentiometric Sensor

Crevice corrosion is a type of local corrosion which occurs when a metal surface is confined in a narrow gap on the order of 10 μm filled with a solution. Because of the inaccessible geometry, experimental methods to analyze the inner space of the crevice have been limited. In this study, a light-addressable potentiometric sensor (LAPS) was employed to estimate the potential distribution inside the crevice owing to the IR drop by the anodic current flowing out of the structure. Before crevice corrosion, the I–V curve of the LAPS showed a potential shift, depending on the distance from the perimeter. The shift reflected the potential distribution due to the IR drop by the anodic current flowing out of the crevice. After crevice corrosion, the corrosion current increased exponentially, and a local pH change was detected where the corrosion was initiated. A simple model of the IR drop was used to calculate the crevice gap, which was 12 μm—a value close to the previously reported values. Thus, the simultaneous measurement of the I–V curves obtained using a LAPS during potentiostatic electrolysis could be applied as a new method for estimating the potential distribution in the crevice.

ANALISIS VARIASI JUMLAH SUDU TURBIN BERPENAMPANG PELAT DATAR PADA TURBIN AIR ALIRAN VORTEX DENGAN TIPE SALURAN MASUK INVOLUTE

2020 ◽  
Vol 7 (2) ◽  
pp. 72-78
Author(s):  
Adnan Al Farisi ◽  
Yopi Handoyo ◽  
Taufiqur Rokhman
Keyword(s):  
Power Plant ◽  
Alternative Energy ◽  
Vortex Flow ◽  
Experimental Methods ◽  
Turbine Efficiency ◽  
A Value ◽  
Current Voltage ◽  
Materials Research ◽  
The One ◽  
Flow Vortex

The One of alternative energy that is environmentally friendly is by untilize water energy and turn it into a Microhydro power plant. Microhydro power plant usually made from utilize the waterfall with the head fell. While utilization for streams with a head small drop is not optimal yet. This is a reference to doing research on harnessing the flow of a river that has a value of head low between 0.7 m – 1.4 m with turning it into a Vortex flow (vortex). The purpose of this research is to know  the effect variation number of blade on power and efficiency in the vortex turbine. This research uses experimental methods to find current, voltage, torque and rpm using a reading instrument. The materials research vortex turbine used 6 blade, 8 blade and 10 blade with flat plate. The result showed the highest efficiency is 29,93 % with produce turbine power is 19,58 W, generated on turbine with variation 10 blade with load 3,315 kg and the capacity of water 10,14 l/s. Followed with an efficiency 24,17% and produce turbine power is 15,81 W, generated on turbine with the variation 8 blade with load 3,315 kg and the capacity of water is 10,14 l/s. The the lowest turbine efficiency 22,32% with produce tuebine power 14,60 W, generated on turbine with the variation 6 blade with load 3,315 kg, the capacity of water is 10,14 l/s.

693. A rejection test for raw milk

1958 ◽  
Vol 25 (1) ◽  
pp. 32-51 ◽  
Author(s):  
Peggy B. Taylor ◽  
L. F. L. Clegg
Keyword(s):  
Lactic Acid ◽  
Ferric Chloride ◽  
Technical Assistance ◽  
Milk Proteins ◽  
Raw Milk ◽  
Ph Change ◽  
Yellow Colour ◽  
A Value ◽  
Keeping Quality

The determination of apparent lactic acid has been used as a basis for a rejection test for raw milk. The method consists of precipitation of milk proteins with barium chloride, sodium hydroxide and zinc sulphate, and the addition of ferric chloride to the filtrate to produce the yellow colour of ferric lactate. Lactic acid is not solely responsible for the production of the yellow colour, which, nevertheless, gives a good relationship with keeping quality of milk (measured as hours to the C.O.B. end-point at 22° C.) and the values have been expressed as ‘apparent lactic acid’.The relationship of winter and summer milks to keeping quality has been studied, and a value of 0·03% apparent lactic acid in milk is equivalent to an average keeping quality of 5¾ and 8½ hr. for winter and summer milks, respectively. A value of 0·03% is recommended as the earliest value of apparent lactic acid at which milk could be rejected.The apparent lactic acid in colostrum and late-lactation milk and in milk from cows suffering from mastitis has been determined, and only in late-lactation milk were the values found to be significantly higher than usual in fresh raw milk, and an inverse relationship between yield and apparent lactic acid is suggested.Permanent glass matching disks have been prepared for use in a Lovibond comparator. This permits the intensity of the yellow colour produced with 1% ferric chloride to be determined and the apparent lactic acid in milk estimated.Grateful acknowledgement is made to the management and staff of the Dairy Department of the Reading Co-operative Society and the Farmer's Clean Milk Dairy, Reading, and local milk producers for supplying samples for experiments; to the N.M.T.S. staff in Reading for help in finding suitable farmers, and to the Dairy Husbandry Department of the N.I.R.D. for information about and samples of abnormal and late-lactation milk. Our particular thanks are due Miss Marie Gruber for technical assistance, to Dr N. J. Berridge for the suggestion and help on the work on pH change as an indication of keeping quality (given in the appendix), and to Dr A. T. R. Mattick for the advice given in this work.

scholarly journals UJI TOKSISITAS AKUT MINUMAN PROBIOTIK SIRSAK GUNUNG (Annona montana Macf.) DENGAN METODE BSLT (Brine Shrimp Lethality Test)

2020 ◽  
Vol 1 (5) ◽  
pp. 941-948
Author(s):  
Ambar Fidyasari ◽  
Sentot Joko Raharjo ◽  
Melani Setyowati
Keyword(s):  
Acute Toxicity ◽  
Traditional Medicine ◽  
Brine Shrimp ◽  
Experimental Methods ◽  
Test Method ◽  
Toxic Effects ◽  
Brine Shrimp Lethality ◽  
Lc50 Value ◽  
A Value ◽  
Acute Toxic

Soursop fruit (Annona montana Macf.) is one of the plants can be used as as traditional medicine. This plant contains terpenoid and acetogenin which can cause toxicity. The fruit has a flavor that is tasteless so the innovation becomes probiotic drinks. This drink has been proven as an antioxidant, antibacterial, antihyperuricemia and antidiarrheal. The aim of this study was to know about acute toxicity of probiotic drink of soursop juice using brine shrimp lethality test method which will be indicated by LC50 value. This study used experimental methods conducted in the Laboratory of Farmakoknosi. There are several variations in concentration in this study, namely 10000 ppm, 20000 ppm, 30000 ppm, 40000 ppm, 50000 ppm, 60000 ppm, 70000 ppm, 80000 ppm and replication was done 3 times with total number of test animals used was 270. The results showed that probiotic drink of soursop juice can provide acute toxic effects on test animals with LC50 value of 29717,23 ppm. LC50 values ​​indicate that the mountain soursop probiotic drink is not potentially toxic because it has a value of >1000 ppm.

scholarly journals Stifling of Crevice Corrosion in Alloy 22 During Constant Potential Tests

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Raul B. Rebak
Keyword(s):  
Aqueous Solutions ◽  
Induction Time ◽  
Crevice Corrosion ◽  
Nucleation And Growth ◽  
Anodic Current ◽  
Critical Stage ◽  
Current Output ◽  
Alloy 22 ◽  
Constant Potential ◽  
High Chloride

Artificially creviced Alloy 22 (N06022) may be susceptible to crevice corrosion in the presence of high-chloride aqueous solutions, especially at higher temperatures and at anodic potentials. The presence of oxyanions in the electrolyte, particularly nitrate, inhibits the nucleation and growth of crevice corrosion. The current results show that crevice corrosion will develop in Alloy 22 when a constant potential above the crevice repassivation potential is applied to a creviced specimen. The analyses of the current output showed the presence of three characteristic domains: (1) passivation or induction time, (2) nucleation and growth, and (3) stifling and arrest. That is, under the tested conditions, crevice corrosion did initiate but after it reached a critical stage of growth, further damage stalled and the output anodic current returned to the passive values before the nucleation of the attack.

A critical crevice solution and IR drop crevice corrosion model

2008 ◽  
Vol 50 (6) ◽  
pp. 1716-1725 ◽  
Author(s):  
Glyn F. Kennell ◽  
Richard W. Evitts ◽  
Kevin L. Heppner
Keyword(s):  
Crevice Corrosion ◽  
Ir Drop ◽  
Corrosion Model

A study on the modeling of parameters affecting the Ir drop mechanism in the initiation stage of crevice corrosion

2000 ◽  
Vol 6 (6) ◽  
pp. 505-511 ◽  
Author(s):  
Hyun-Young Chang ◽  
Yong-Soo Park ◽  
Woon-Suk Hwang
Keyword(s):  
Crevice Corrosion ◽  
Ir Drop ◽  
Initiation Stage

POLYCONDENSED ANIONS OF THE TRANSITION METALS: LIGHT SCATTERING AND ULTRACENTRIFUGATION WITH SCHLIEREN AND INTERFERENCE OPTICS OF ALKALINE NIOBIUM (V) SOLUTIONS

1964 ◽  
Vol 42 (4) ◽  
pp. 731-743 ◽  
Author(s):  
Wilfred H. Nelson ◽  
R. Stuart Tobias
Keyword(s):  
Light Scattering ◽  
Experimental Methods ◽  
Degree Of Polymerization ◽  
Potassium Ions ◽  
High Symmetry ◽  
Concentrated Solutions ◽  
Solvent Water ◽  
A Value ◽  
The Stability ◽  
Equilibrium Ultracentrifugation

Alkaline aqueous niobium(V) solutions prepared by dissolving the salt K14Nb12O37•27H2O were studied by means of light scattering and by equilibrium ultracentrifugation by using both schlieren and interference optics. All three experimental methods indicate that the degree of polymerization of the polycondensed niobate anion is no less than 5 and probably has the value 6. The centrifugation data indicate that only one polycondensed species exists in the solutions. The effective charge of the niobate anion appears to be reduced appreciably by the binding of potassium ions to a value of no greater than −2. The behavior of the solutions is very similar to that observed previously with alkaline tantalum(V) solutions, and it appears very likely that the hexameric anion [HNb6O19]−7 found in niobate crystals also exists in aqueous solutions. The niobate is slightly protonated in comparison to the analogous tantalate. The stability of highly concentrated solutions containing this large polycondensed species is probably the result of the existence of a poly-ion with high symmetry which interacts only weakly with the solvent, water.

scholarly journals The puzzle of the proton radius

2020 ◽  
Author(s):  
Amira Val Baker
Keyword(s):  
Standard Model ◽  
Experimental Methods ◽  
Review Article ◽  
Experimental Results ◽  
Current Status ◽  
Proton Radius ◽  
A Value ◽  
The Standard Model

The radius of the proton is a topic of debate and has yet to be confirmed. Measurements from different techniques yield conflicting values, with some experimental methods yielding a value in disagreement with the standard model. This review article outlines the current status of the experimental results and summarizes the possible solutions to this puzzle.

scholarly journals Penerapan Layanan Bimbingan Kelompok dalam Mencegah Kenakalan Remaja

2020 ◽  
Vol 2 (1) ◽  
pp. 5-8
Author(s):  
Khairil Syahputra ◽  
M. Edwar Romli ◽  
Nurlela Nurlela
Keyword(s):  
Data Analysis ◽  
Juvenile Delinquency ◽  
Hypothesis Testing ◽  
Group Counseling ◽  
Student Behavior ◽  
Research Method ◽  
Experimental Methods ◽  
Counseling Services ◽  
Guidance Services ◽  
A Value

The problem in this study is that there are often deviations in student behavior which results in students breaking the rules of discipline at school. Namely skipping school, often late, smoking and fighting. This study aims to determine whether the application of group counseling services in preventing the delinquency of juvenile students in SMA Negeri 9 Palembang effectively. The research method used is a quantitative approach with pre experimental methods with OneGroup Pretest and Posttest Design. The subjects of this study were students of class XI IPS 1 of SMA Negeri 9 Palembang with a sample of 10 students. From the results of data analysis shows that the total pretest value before treatment was 586 with an average of 58.6 and the results of the posttest after being treated with a value of 842 with an average of 84.2. Hypothesis testing results prove that the results of the t-test calculations where t-count = 5.039≥ t-table = 1.833. thus the application of group guidance services in preventing juvenile delinquency from students is effectively accepted.

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