REVIEW

The development of affordable and efficient vacuum cleaners has become a significant concern for households and small-scale cleaning businesses, especially in developing regions where high-end vacuum cleaners are often too expensive. Vacuum cleaners are essential tools in maintaining clean indoor environments by removing dirt, dust, and other debris from floors and surfaces. However, the design and functionality of many low-cost vacuum cleaners are often compromised, especially in terms of air velocity, particle retention, and the efficiency of dust separation. These issues can lead to ineffective cleaning and the release of fine dust particles into the environment, undermining the overall effectiveness of the vacuum cleaner. Previous designs of vacuum cleaners fabricated from locally available materials often suffer from limitations such as inadequate air velocity through the wand, improper filtration of fine particles, and ineffective dust deposition mechanisms. These flaws not only reduce the cleaning efficiency but also compromise air quality in the environment. This study aims to review and improve upon the design and fabrication of such vacuum cleaners, addressing these critical issues to enhance performance and dust control.

Single phase inverters play an essential role in applications such as uninterruptible power supplies and renewable energy systems, yet their operation is often affected by faults including short circuits, open circuit conditions, and DC link overvoltage. This work reviews these common fault types, their characteristic influence on inverter performance, and the protective measures commonly employed to limit their impact and ensure reliable operation. The study involved identifying and classifying major inverter faults, examining the protection techniques typically used in practice, and developing a simulation model of a single phase H - bridge inverter for controlled analysis. Selected protection devices, including fast acting fuses, electronic current limiting circuits, and voltage clamping components, were examined under various fault scenarios, with parameters such as Response Time, Detection Rate, and Fault Coverage used for evaluation. Observations from the simulation provided insight into how the inverter behaves when exposed to different fault scenarios and how each protection device influences system response. The patterns revealed through these analyses highlight the importance of rapid fault handling, effective voltage suppression, and balanced device coordination. Based on these insights, the study emphasizes the value of adopting a multilayered protection arrangement that integrates fast electronic sensing with traditional isolation components to enhance the overall safety, reliability, and cost effectiveness of single phase inverter systems.

Due to the general increase in the usage of petroleum resources, drilling of oil wells are frequently done in very challenging and hostile settings. Loss of circulation has been one of the main challenge facing engineers during drilling operations. Hence there have been extensive researches done over the years in order to minimize the impact of loss circulation, however, this have led to a myriad of viewpoints as to what product and method is suitable to battle it. However, a lot of the products and guidelines available for battling lost circulation are often biased towards self-promotion for a particular service company. The purpose of this study is to develop practical guidelines that are universal and not biased towards any particular service company product and which will also serve as a reference guide for lost circulation prevention and control at the well-site for drilling personnel