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In this study, a novel power efficient implicit pulsed-triggered flip-flop with embedded clock-gating and pull-up control scheme (IPFF-CGPC) is proposed. By applying an XOR-based clock-gating scheme in the pulse generating stage, which conditionally disables the inverter chain when the input keeps unchanged, IPFF-CGPC is able to gain low power efficiency by eliminating redundant transitions of internal nodes. Meanwhile, a pull-up control scheme is applied to enhance the discharging path and save short-circuit power when D makes '0'-'1' transition. To further improve the robustness of the proposed design, the XOR-based comparator in the clock-gating scheme is replaced by a transmission gate-based comparator, which results in an enhanced version (IPFF-ECGPC). Based on the SMIC 65 nm technology, extensive post-layout simulation results show that IPFF-CGPC exhibits excellent power characteristic with a reduction of 32.06-85.89% against its rival designs at 10% data switching activity. Due to its power efficiency, its power-delay product (PDP) gains an improvement of up to 73.94% in the same condition. Moreover, IPFF-ECGPC also enjoys outstanding total-power and PDP efficiency at 10% data switching activity. Therefore, the proposed designs are suitable for power-constrained applications in very-large-scale integration designs which are speed-insensitive.

Carbon and nutrients as well as suspended solids (SS) removal by chemically enhanced primary treatment (CEPT) were conducted in the Qingshan wastewater treatment plant in Huangshi, Hubei Province. Feasibility of this process for wastewater treatment were investigated in detail by comparing the removal performance of three inorganic chemical coagulants (polyaluminium chloride, polyaluminium ferric chloride [PAFC] and poly ferric sulfate) individual or couple with poly acrylamide, optimizing the conditions during CEPT by both single factor analysis and orthogonal test designs. The results of this study demonstrated that CEPT turned out to be an effective method for wastewater treatment, with PAFC as the optimal coagulant, which showed preeminent removal capacity for chemical oxygen demand, total phosphorus and SS. The optimal working condition could be at pH 7.0, settling time 15 min, and velocity gradient of 174.80 and 15.56 s −1 for mixing and reaction phase respectively. While the coagulant dosage depends on raw water attributes, which had a decisive effect on CEPT treatment performances. However, the three coagulants behaved poorly in nitrogen removal.