Changes in solar activity are regularly forwarded as an hypothesis to explain the observed global warming over the last century. The support of such claims is largely statistical, as knowledge of the physical relationships is limited. The statistical evidence is revisited. Changing solar activity is a statistically plausible hypothesis for the observed warming, if short-term natural variability...

Gaplek is a processed product of cassava that requires drying process to remove the water content in cassava. Solar thermal energy can be used for gaplek by using greenhouse effect system. However, system solar very dependent on weather conditions and temperature difficult control. Therefore, control proposed this study utilizing Pulse Width Modulation (PWM) exhaust fan speed. Thus, maintained ...