dcal [15 °C](decicalorie)

Unit decicalorie (dcal) is a unit of measurement for energy, specifically heat energy. It is equal to 10 calories or 0.01 kilocalories (kcal), where one calorie is defined as the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius. In this context, the notation [15 °C](decicalorie) implies that the heat energy is being measured with reference to a 15°C temperature.

Decicalorie is commonly used in thermodynamics and heat transfer studies, where small amounts of energy are involved in processes like heating, cooling or phase transitions of substances. This unit is also encountered in nutrition and food sciences, as it helps quantify the energy content of food items in human diets. However, Calorie (capital C) or kilocalorie is the more commonly used unit in these fields, with 1 Calorie being equal to 100 dcal.

Overall, the unit decicalorie [15 °C] is a measure of energy used to express the heat or thermal energy involved in various scientific applications.

MMBTU [IT](million British thermal units)

MMBTU, or Million British Thermal Units (MM is the Roman numeral for one thousand times one thousand), is a unit of measurement in the field of energy. The British thermal unit (BTU) is a unit of heat used in the Imperial and United States customary systems, where one BTU is roughly equivalent to the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.

In the context of energy, the MMBTU is often used to measure the energy content of fuels, such as natural gas, oil, or coal. It represents a quantity of one million BTUs and can be used to compare the energy content of different fuels, or to quantify the amount of heat energy produced by a power plant or industrial process.

The MMBTU is an "IT" or "International Table" BTU unit, which means it's based on the IT calorie and is widely used in the global energy sector. It is important to note that the MMBTU can be converted to other energy units, such as kilowatt-hours, joules, or calories, depending on the intended application or standard used in a specific industry or region.