Noise Level Investigation and Control of Household Electric Power Generator

Electric power generator is an essential household facility particularly in developing countries. It exists in various capacities and makes in shops, offices, workshops and factories. The attendant environmental risks of this source of power supply are major challenges to users both at household and industrial level. Efforts through research and development are still on-going to mitigate the prevailing health hazards. This study investigates noise level of typical portable generator (2 kW/220 V) and the sound absorbance capacity of an acoustic enclosure developed from a multilayer panel made of locally sourced galvanized metal sheet (0.90 mm), Polyurethane acoustic foam (7.50 mm), Particle board (35.0 mm) and plywood (10.0 mm). The noise produced by the generator when on load and no load were considered for cases of it being placed inside and outside the enclosure and compared with acceptable OSHA safe thresholds noise level for the school environment where the study was carried out. The result shows a significant reduction of noise produced indicating a shift from very laud threshold (average of 86.23 dB (A)) for no load and no enclosure to moderately low region (average of 69.34 dB (A)) for the case of no load using enclosure. Likewise considering loaded scenario similar trend was recoded with average acoustic capacity of the enclosure of 23.20 dB (A). The effect of the enclosure is positive and the potential benefits of improved noise absorption panels to enhance better performance of the developed enclosure for office and household generators was established. Keywords: Electric Generator, Enclosure Panel, Noise control, Load, Household

Development of a Liquidified Petroleum Gas Leakage Detector, Level Indicator and Automatic Shutdown System

Fire outbreak prevalence is a disastrous occurrence across the globe, its causes vary but, a major portion of these outbreaks result from gas explosions, mostly caused by gas leakages in residential, commercial premises and gas powered transportation systems. A very effective preventive measure to avoid the menace associated with it is to install a gas leakage detector at vulnerable locations. Difficulty in detecting /managing gas level often posed inconveniences as it sometimes gets exhausted unexpectedly, when the user cannot possibly get access to buy more. This study presents a system capable of indicating gas levels by continuously measuring the weight of the cylinder, detecting gas leakage and alert the user through alarm and status display while automatically shutting down the supply valve as a major safety measure. This was implemented with the Resistive force sensor, MQ6 gas sensor and Arduino mega. This device can be used in residential premises and commercial establishments like hotels, retail shops, gas plants amongst others, while ensuring better safety of all the stakeholders thereby improving profit

Noise Level Investigation and Control of Household Electric Power Generator

Electric power generator is an essential household facility particularly in developing countries. It is made by various manufacturers in sizes and capacities and found in business centres, offices, workshops and factories. The attendant environmental risks of this source of power supply are major challenges to users both at household and industrial level. Efforts through research and development are still ongoing to mitigate the prevailing health hazards. This study investigates noise level of typical portable generator (2 kW/220 V, 18 kg, and 370×330×320 mm) and the sound absorbance capacity of an acoustic enclosure (440×440×440 mm) developed from a multilayer panel made of locally sourced galvanized metal sheet (0.90 mm), Polyurethane acoustic foam (7.50 mm), Particle board (35.0 mm) and plywood (10.0 mm). The noise produced by the generator when on load and no load were considered for cases of it being placed inside and outside the enclosure and compared with acceptable OSHA safe thresholds noise level for the school environment where the study was carried out using Sound Level Meter HD600 (IEC 61672-1) by Extech Inc. USA. The result shows a significant reduction of noise produced indicating a shift from very laud threshold with average of 86.23 dB (A) for no load and no enclosure to moderately low noise level (average of 69.34 dB(A)) for the case of no load using enclosure. Likewise considering loaded scenario similar trend was recorded with average acoustic capacity of the enclosure of 23.20 dB(A). The effect of the enclosure was noticed and the potential benefits of improved noise absorption panels to enhance better performance of the developed enclosure for office and household generators was established. Â

Initial invasive or conservative strategy for stable coronary disease

BACKGROUND Among patients with stable coronary disease and moderate or severe ischemia, whether clinical outcomes are better in those who receive an invasive intervention plus medical therapy than in those who receive medical therapy alone is uncertain. METHODS We randomly assigned 5179 patients with moderate or severe ischemia to an initial invasive strategy (angiography and revascularization when feasible) and medical therapy or to an initial conservative strategy of medical therapy alone and angiography if medical therapy failed. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest. A key secondary outcome was death from cardiovascular causes or myocardial infarction. RESULTS Over a median of 3.2 years, 318 primary outcome events occurred in the invasive-strategy group and 352 occurred in the conservative-strategy group. At 6 months, the cumulative event rate was 5.3% in the invasive-strategy group and 3.4% in the conservative-strategy group (difference, 1.9 percentage points; 95% confidence interval [CI], 0.8 to 3.0); at 5 years, the cumulative event rate was 16.4% and 18.2%, respectively (difference, 121.8 percentage points; 95% CI, 124.7 to 1.0). Results were similar with respect to the key secondary outcome. The incidence of the primary outcome was sensitive to the definition of myocardial infarction; a secondary analysis yielded more procedural myocardial infarctions of uncertain clinical importance. There were 145 deaths in the invasive-strategy group and 144 deaths in the conservative-strategy group (hazard ratio, 1.05; 95% CI, 0.83 to 1.32). CONCLUSIONS Among patients with stable coronary disease and moderate or severe ischemia, we did not find evidence that an initial invasive strategy, as compared with an initial conservative strategy, reduced the risk of ischemic cardiovascular events or death from any cause over a median of 3.2 years. The trial findings were sensitive to the definition of myocardial infarction that was used