National primary special standard for the unit of pulsed electrical voltage with pulse durations of 4·10–11 to 1·10–5 sec

In this work, a biomimetic sensor elaborated by direct electrospinning of molecular imprinted poly (ethylene co-vinyl alcohol) (EVOH) onto gold electrodes was proposed for impedimetric creatinine detection. Dimethylsulfoxyde (DMSO) was selected as polymer solvent and creatinine (1% wt) was used as template. In the optimal conditions of fabrication (20% wt EVOH, electrical voltage: 20 kV, collection distance: 30 cm), the sensor response was proportional to log [creatinine concentratio in the 1 fg.L-1-1 μg.L-1 range. We also showed that the sensor could be reused at least three times and that the response of the non imprinted polymer control sensor, prepared the same way but in absence of creatinine, was very low.

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Study of Electrostatic-Induced Jumping Droplets on Superhydrophobic Surfaces

Volume 8: Heat Transfer and Thermal Engineering ◽

10.1115/imece2017-70311 ◽

2017 ◽

Cited By ~ 1

Author(s):

B. Traipattanakul ◽

C. Y. Tso ◽

Christopher Y. H. Chao

Keyword(s):

Heat Transfer ◽

High Speed ◽

Electrostatic Force ◽

Droplet Radius ◽

Inertia Force ◽

Resistance Force ◽

Average Charge ◽

Electrical Voltage ◽

Fluid Systems ◽

Set Up

Condensation of water vapor is an important process utilized in energy/thermal/fluid systems. When droplets coalesce on the non-wetting surface, excess surface energy converts to kinetic energy leading to self-propelled jumping of merged droplets. This coalescing-jumping-droplet condensation can better enhance heat transfer compared to classical dropwise condensation and filmwise condensation. However, the resistance force can cause droplets to return to the surface. These returning droplets can either coalesce with neighboring droplets and jump again, or adhere to the surface. As time passes, these adhering droplets can become larger leading to progressive flooding on the surface, limiting heat transfer performance. However, an electric field is known to be one of the effective methods to prevent droplet return and to address the progressive flooding issue. Therefore, in this study, an experiment is set up to investigate the effects of applied electrical voltages between two parallel copper plates on the jumping height with respect to the droplet radius and to determine the average charge of coalescing-jumping-droplets. Moreover, the gravitational force, the drag force, the inertia force and the electrostatic force as a function of the droplet radius are also discussed. The gap width of 7.5 mm and the electrical voltages of 50 V, 100 V and 150 V are experimentally investigated. Droplet motions are captured with a high-speed camera and analyzed in sequential frames. The results of the study show that the applied electrical voltage between the two plates can reduce the resistance force due to the droplet’s inertia and can increase the effects of the electrostatic force. This results in greater jumping heights and the jumping phenomenon of some bigger-sized droplets. With the same droplet radius, the greater the applied electrical voltage, the higher the coalescing droplet can jump. This work can be utilized in several applications such as self-cleaning, thermal diodes, anti-icing and condensation heat transfer enhancement.

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Efek Tegangan Listrik dan Waktu Proses Elektroplating Krom Keras terhadap Tebal Lapisan

Jurnal Energi Dan Manufaktur ◽

10.24843/jem.2019.v12.i02.p05 ◽

2019 ◽

Vol 12 (2) ◽

pp. 75

Author(s):

Ketut Suarsana ◽

I M. Astika ◽

D.N.K Putra Negara

Keyword(s):

Surface Layer ◽

Layer Thickness ◽

Coating Process ◽

Electrical Voltage ◽

Wear And Corrosion ◽

Chrome Coating ◽

Time Variations ◽

Coating Time ◽

Hard Chrome ◽

Wear And Corrosion Resistance

Proses pelapisan krom keras merupakan proses akhir atau tahap penyelesaian pada kebanyakan pembuatan komponen agar tidak cepat aus, seperti pada poros, pasak, ring piston, silinder, bearing dan crank shaf. Dalam bidang industri sifat mekanik yang banyak diperlukan pada logam yang dipergunakan adalah kemampuannya untuk tahan aus dan tahan korosi yang mana kita ketahui logam mempunyai reaksi yang sangat aktif terhadap perubahaan temperatur dan cuaca, maka perlu dilakukan pelapisan sehingga kemungkinan suatu bahan logam terkena korosi bisa dihambat. Bahan spesimen yang di gunakan adalah Baja St 60 (C 0.40%; Mn 7%; Si 0.28%; P+S 0.09%; Fe 98,53%) dengan variasi tegangan listrik: 4, 6, dan 8 volt, untuk variasi waktu elektroplating krom keras 30, 45, dan 60 menit. Pengujian yang dilakukan dengan pengukuran ketebalan lapisan menggunakan skala foto mikro dan menghitung ketebalan lapisan permukaan. Hasil penelitian menunjukkan bahwa semakin tinggi tegangan listrik yang digunakan dan semakin lama waktu proses pelapisan krom keras maka meningkat ketebalan lapisannya. Ketebalan lapisan permukaan yang paling tebal didapatkan pada tegangan 8 volt dengan waktu pelapisan 60 menit dengan ketebalan lapisannya sebesar 89,37 ?m, sedangkan ketebalan lapisan permukaan tipis didapat pada tegangan 4 volt dengan waktu pelapisan 30 menit ketebalan lapisannya sebesar 20,18 ?m. Jadi tegangan listrik dan waktu electroplating dapat mempengaruhi dan memberikan efek terhadap ketebalan lapisan yang terjadi pada Baja St.60. The hard chrome coating process is the final process or completion stage in most parts making so as not to wear out quickly, such as on the shaft, pegs, piston rings, cylinders, bearings and crank shafts. In the industrial field of mechanical properties that are much needed in the metal used is its ability to withstand wear and corrosion resistance which we know metals have a very active reaction to changes in temperature and weather, coating is necessary so that the possibility of a metal being corroded can be inhibited. The specimens used were Baja St 60 (C 0.40%; Mn 7%; Si 0.28%; P + S 0.09%; Fe 98.53%) with variations in electrical voltage: 4, 6 and 8 volts, for time variations hard chrome electroplating 30, 60 and 90 minutes. Tests carried out by measuring the thickness of the layer use a micro photo scale and calculate the thickness of the surface layer. The results showed that the higher the voltage used and the longer the coating process was hard chrome, the thickness of the layer increased. The thickest surface layer thickness was obtained at 8 volts with a coating time of 60 minutes with a layer thickness of 89.37 ?m, while the thickness of the thin surface layer was obtained at a voltage of 4 volts with a coating time of 30 minutes layer thickness of 20.18 ?m. So the electrical voltage and time of electroplating can affect and give effect to the thickness of the coating that occurs in Steel St.60

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