PHOSPHORUS RECOVERY FROM SEWAGE-SLUDGE MOLTEN SLAG USING A COMBINATION OF ACID-DISSOLUTION, ALKALI-PRECIPITATION, AND ION-EXCHANGE

We recently reported an efficient procedure for recovering phosphoric acid from dephosphorization slag. This recovery procedure consists of a combination of the following four processes: (1) A first dissolution process of slag in a nitric acid solution; (2) a precipitation process then adds ammonia to the obtained eluate; (3) a second dissolution process dissolves the precipitation from the nitric acid eluate; and, (4) the final process involves ion exchange in which the obtained eluate is passed through an ion exchange resin. In the present study, this recovery procedure was applied to concentrate and recover phosphorus from sewage-sludge molten slag, which is an unused resource that should be considered a new resource for phosphorus. As a result, our procedure for recovery from dephosphorization slag was viable following two revisions. Initially, the time for the first dissolution process was extended from 0.2 h to 1 h, but 0.2 h proved to be the optimum time for dephosphorization slag. Next, we discovered it was better to perform the filtration one day after adding the ammonia instead of immediately after adding it. The other two processes could be treated under substantially the same conditions as in the case of dephosphorization slag, and high-purity phosphorus was obtained

A Study on Energy Reduction in Quality-driven Digital Wireless Communication Systems

ディジタル無線通信システムの低消費エネルギー化のための手法として，送信信号の信号電力を変化させ るものがある．これは消費エネルギーとデータの誤り率とのトレードオフを考慮した手法である．信号電力を変化さ せることにより送信機の低消費エネルギー化は行えるが，受信機の消費エネルギーは変化しない．本稿では信号電力 に加え受信機の演算精度を考慮することにより送受信機両方の消費エネルギー削減を行う．そのための通信路解析を 行い，受信機における消費エネルギーは最大89%，システム全体を考慮した場合最大69%の消費エネルギーが削減可 能であることを示した．One major method for reduction of energy consumption in digital wireless communication systems is to control transmission signal power. This method consider trade offs between signal power and data error rate. It can be achieved by control signal power to energy reduction in transmitter, but not in receiver. So in addition to signal power control in transmitter, precision control in receiver can reduce energy consumption in both transmitter and receiver. In this paper,channel characterization and analysys make clear the posibbility of 89 % energy reduction in receiver and 69 % in communication system

通信品質を考慮したディジタル無線通信システムの低消費エネギー化の検討

ディジタル無線通信システムの低消費エネルギー化のための手法として，送信信号の信号電力を変化させ るものがある．これは消費エネルギーとデータの誤り率とのトレードオフを考慮した手法である．信号電力を変化さ せることにより送信機の低消費エネルギー化は行えるが，受信機の消費エネルギーは変化しない．本稿では信号電力 に加え受信機の演算精度を考慮することにより送受信機両方の消費エネルギー削減を行う．そのための通信路解析を 行い，受信機における消費エネルギーは最大89%，システム全体を考慮した場合最大69%の消費エネルギーが削減可 能であることを示した．One major method for reduction of energy consumption in digital wireless communication systems is to control transmission signal power. This method consider trade offs between signal power and data error rate. It can be achieved by control signal power to energy reduction in transmitter, but not in receiver. So in addition to signal power control in transmitter, precision control in receiver can reduce energy consumption in both transmitter and receiver. In this paper,channel characterization and analysys make clear the posibbility of 89 % energy reduction in receiver and 69 % in communication system