Effect of standby mode operation of some household appliances on disturbance voltage and current in frequency range of 9–150 kHz produced by other equipment in low voltage network
Most household appliances commercially available today on the market are equipped with the inverter technology favoring to its smaller size, advanced performance, and energy efficient. Notwithstanding its benefits, unfortunately, this technology may introduce current disturbance according to its relevant frequency switching and eventually degrades power quality. The switching frequency of inverter for household appliances is generally in the range of 9-150 kHz causing the disturbance and may influence the working performance of other appliances. The voltage and current disturbances in the frequency range of 9-150 kHz are not completely covered and currently subject to standardization work. Some household appliances can be operated in standby mode in order to display the time and setting information or to allow them to operate quickly even though it also gives a drawback regarding to its energy consumed. This study investigates the characteristics of standby mode operation of some appliances and its effect to the voltage and current disturbance in the frequency range of 9-150 kHz. The result shows that the standby mode operation of particular household appliances can filter and significantly reduce the voltage and current disturbance in the low voltage (LV) installation network for specific frequency in the range of 9-150 kHz.
Emission and immunity of equipment in the frequency range 2 to 150 kHz
This paper gives an overview of emission and immunity standards in the frequency range from 2 to 150 kHz. Based on existing standardization a complete set of limits is proposed by the authors. A distinction is thereby made between narrowband emission, broadband emission and recurrent oscillations. The measuring technique is vital to the results. In this frequency range, there are two different sets of standards covering measurement equipment. Due to fact of development of time-domain based instrument we propose to only use this type of instruments for the whole frequency range.
Improved Skin Penetration Using In Situ Nanoparticulate Diclofenac Diethylamine in Hydrogel Systems: In Vitro and In Vivo Studies
Delivering diclofenac diethylamine transdermally by means of a hydrogel is an approach to reduce or avoid systemic toxicity of the drug while providing local action for a prolonged period. In the present investigation, a process was developed to produce nanosize particles (about 10 nm) of diclofenac diethylamine in situ during the development of hydrogel, using simple mixing technique. Hydrogel was developed with polyvinyl alcohol (PVA) (5.8% w/w) and carbopol 71G (1.5% w/w). The formulations were evaluated on the basis of field emission scanning electron microscopy, texture analysis, and the assessment of various physiochemical properties. Viscosity (163–165 cps for hydrogel containing microsize drug particles and 171–173 cps for hydrogel containing nanosize drug particles, respectively) and swelling index (varied between 0.62 and 0.68) data favor the hydrogels for satisfactory topical applications. The measured hardness of the different hydrogels was uniform indicating a uniform spreadability. Data of in vitro skin (cadaver) permeation for 10 h showed that the enhancement ratios of the flux of the formulation containing nanosize drug (without the permeation enhancer) were 9.72 and 1.30 compared to the formulation containing microsized drug and the marketed formulations, respectively. In vivo plasma level of the drug increased predominantly for the hydrogel containing nanosize drug-clusters. The study depicts a simple technique for preparing hydrogel containing nanosize diclofenac diethylamine particles in situ, which can be commercially viable. The study also shows the advantage of the experimental transdermal hydrogel with nanosize drug particles over the hydrogel with microsize drug particles.