Final answer:
A positive value of Hconduction indicates that the direction of heat flow is into the body, raising its temperature. Heat conduction occurs when there is direct contact between two objects, with heat flowing from warmer to cooler. The positive or negative signs in thermodynamic equations represent the direction of heat transfer.
Step-by-step explanation:
If the value of Hconduction of the body core is positive, this indicates that the direction of heat flow is into the system. By convention in thermodynamics, heat flow (Q) is considered positive when it transfers energy into the system, and it is negative when energy is transferred out of the system. Therefore, a positive Hconduction means that heat is being conducted into the body core, raising its temperature.
When discussing conduction, we refer to the heat transfer that occurs between two objects that are in direct contact with one another. For instance, when your skin touches a warm surface, heat flows from the surface to your skin. In the human body, about 3 percent of the body's heat is lost through conduction when it comes in contact with cooler objects, conversely, if an object is warmer, the body gains heat.
In all cases, the direction of heat flow is indicated by the sign in front of the heat transfer value. For example, Q = Qh - Qc, where Qh is positive when heat is absorbed by the system and Qc is positive when heat is released by the system but is preceded by a negative sign in this equation to indicate net heat loss.