Intermittent current

Regulatory barriers. Existing regulations that have created incentives for the control and containment of wastes are at the same time discouraging the exploration of pollution-prevention alternatives. Moreover, since regulatory enforcement is often intermittent, current legislation can weaken waste-reduction incentives. 

Amperage limitation, current cycling, or intermittent current application lengthens the required coating time, since it is the applied ampere seconds (Coulombs) that produce the electrodeposit. 

One of the most fruitful developments was the concept of the unidirectional transport of particles by oscillatory or intermittent currents. The onshore movement of fine-grained suspended sediment has been discussed for the U. S. Atlantic coast by Meade (1969) and Hathaway (1972), and for the Dutch Wadden Sea by Postma (1961). The unidirectioneil transport of sand by tidal currents has been documented in a variety of coastal environments by the form and migration of bed forms (Guilcher, 1967 Salsman et ai, 1966 Jones et al., 1965 Belderson and Kenyon, 1969 Caston and Stride, 1970 Ludwick, 1972 Stride, 1974 Bokuniewicz et al., 1977). 

In the framework of a land reclamation project, electrokinetics was applied in combination with preloading and prefabricated vertical drains to improve the mechanical strength of marine sediments intermittent current and noninsulated electrodes were adopted (Lo et al, 2000). The results showed that the mechanical properties of sediment were signiflcantly improved in the vicinity of the electrodes after 22-34 days, by applying voltage gradients ranging between 9.5 and 28.2V/m. 

Micic S, Shang JQ, Lo KY, Lee YN, Lee SW. (2001). Electrokinetic strengthening of a marine sediment using intermittent current. Canadian Geotechnical Journal 38(2) 287-302. 

N. R. Buenfeld, Cathodic protection afforded by an intermittent current applied to reinforced concrete . 

Tiurlikova, L. P., and Lassi, N. I., The effect of anode of constant intermittent current on the regenerative process in skeletal muscle, Biull. Eksp. Biol. Med., 63, 71-74 (1967). 

Figure 16.3 Simplified diagram of a load profile for an electric appliance with intermittent current load.

Loads of welding sets, which have intermittent duty cycles, are mostly single phase, cause low p.f. and stress the generator windings intermittently. Unbalanced loads, such as single phase loads, distributed unevenly cause current unbalance and low p.f. 

Six caustic soda evaporators were anodically protected against stress corrosion in the aluminum industry in Germany in 1965 [27]. Each evaporator had an internal surface area of 2400 m. The transformer-rectifier had a capacity of 300 AJ 5 V and was operated intermittently for many years. Automatic switching on of the protection current only took place in case of need when the drop in potential reached... 

What are the best guess maximum and minimum limits of the load current and are there any intermittent characteristics in its current demand such as those presented by motors, video monitors, pulsed loads, and so forth Always add 50 percent more to what is told to you since these estimates always turn out to be low. Also what are the maximum excursions in supply voltage that the designer feels that the circuit can withstand. This dictates the design approaches of the cross-regulation of the outputs, and feedback compensation in order to provide the needs of the loads. 

Room air currents favorable to capture Contaminants of low toxicity or of nuisance value only Intermittent, low production Large hood large air mass in motion... 

Contaminants of low toxicity or of nuisance value, 3. Intermittent low production, 4. Large hood—large air mass in motion. Upper end of range, I. Disturbing room air currents, 2, Contaminants of high toxicity, 3. High production or heavy use, 4. Small hood—local control only. 

The lower end of the range applies when (a) rhc room air currents are minimal or favorable to capture, (h) the contaminant is of low toxicity or nuisance value only, (c) the tank is used only intermittently, and (d) there is a large exhaust hood, i.e., there is a large air mass in motion. 

The PDE3 inhibitor, cilostazol, has been used as an antithrombotic agent and is currently being used in patients being treated for intermittent claudication. Cilostazol is also used for the prevention of restenosis after treatments such as angioplasty. Another PDE3 selective inhibitor, milrinone, has been used in the treatment of congestive heart failure. Milrinone also has been shown to increase the conductance of the CFTR transporter in vitro. 

PI (adenosine) receptors were explored as therapeutic targets before P2 receptors. Adenosine was identified early and is in current use to treat supraventricular tachycardia. A2a receptor antagonists are being investigated for the treatment of Parkinson s disease and patents have been lodged for the application of PI receptor subtype agonists and antagonists for myocardial ischaemia and reperfusion injury, cerebral ischaemia, stroke, intermittent claudication and renal insufficiency. 

It is worthwhile to note here that in Figs. 3 and 4 the current densities measured at a methanol and air flow rates of 2 ml/min and 2 L/min, respectively show the inconsistency even at the same operating conditions. The reason is expected to be due to the water produced at the cathode. Comparing Figs. 3 and 4, the measured current density response looks quite unstably scattered at low air flow rates in Fig. 3, while it seems to be stable even at the low methanol flow rates in Fig. 4. This instability of measured current density in Fig. 4 could have caused by the water formed at the cathode during the operation of the stack. In fact, it has been observed from the experiment that the water produced at the cathode looks accumulated in the cathode flow channels for a while and it bursts out intermittently to the cathode outlet. Based on the experimental observations, for the stable operation of the 5W... 

The formation of new nuclei and of a fine-crystalline deposit will also be promoted when a high concentration of the metal ions undergoing discharge is maintained in the solution layer next to the electrode. Therefore, concentration polarization will have effects opposite those of activation polarization. Rather highly concentrated electrolyte solutions, vigorous stirring, and other means are employed to reduce concentration polarization. Sometimes, special electrolysis modes are employed for the same purposes currents that are intermittent, reversed (i.e., with periodic inverted, anodic pulses), or asymmetric (an ac component superimposed on the dc). 

A 25-year-old Caucasian woman presents to the university student clinic with complaints of intermittent crampy abdominal pain and four to five loose stools per day. She describes some visible mucus and blood in the stool and states that these symptoms have been present for 6 to 8 weeks. She also has intermittent lower back pain, fatigue, fever, and a 10-lb (4.5 kg) weight loss. The back pain started about the same time as her gastrointestinal symptoms. She denies any sick contacts and has not eaten any take-out or restaurant food over the last 2 months. She takes nonprescription naproxen as needed for aches and pains. She has been using more naproxen recently because of the back pain. She also takes an oral contraceptive pill once daily. She consumes alcohol socially and currently smokes 1/2 to 1 pack of cigarettes per day. 

---