4.4 Trade-Offs
57
R1 = 0.2 (= 1-C1), WR1 = 0.4 in Fig. 4.11c. For cSE = 60% and WR1 = 0.5,
C1 = 0.75 in Fig. 4.12c, and R1 = 0.25 in Fig. 4.13c.
• iSE decreases toward its minimum (zero) if WC1 and WR1 decrease toward
zero (on the limit, iSE = WC1 = WR1 = 0). WC1 = 0 means totally useless
Consumption or C1 = 0. WR1 = 0 means totally polluted Return or R1 = 0.
• iSE goes toward WC1 if C1 goes toward one, or WC1 and WR1 get closer to each
other (on the limit, iSE = WC1 = WR1).
– If in a real case WC1 is always greater than WR1, which seems to be a valid
condition in most of the situations if not all, then the maximum that iSE can
achieve is WC1.
– If WC1 < WR1, then iSE > WC1; If WC1 > WR1, then iSE > WR1.
• iSE goes toward WR1 if R1 goes toward one.
• iSE goes toward C1 if WC1 goes toward one and WR1 goes toward zero.
• cSE decreases toward its minimum (zero) as WC1 and/or C1 goes toward zero.
• cSE increases toward its maximum (WC1) as WR1 and/or C1 goes toward one.
Fig. 4.9 Contour lines of WR1-WC1-cSE trade-offs and patterns along four R1 values