Zero solids treatment

Zero solids treatment (ZST) is a further enhancement of AVT and MT programs and, as its name suggests, the program employs extensive pre- and post-treatment equipment to ensure the highest possible FW and BW purity. ZST has been employed in the secondary circuits of nuclear-powered SGs as an aid in the prevention of SCC, crevice corrosion, and denting, especially where condenser cooling is effected by the use of brackish or estuarine waters. 

Mixed Bed NHjOH Cycle High pressure steam generators invariably operate on an All Volatile Treatment (AVT) or zero solids treatment which means that any conditioning of the water-steam circuit uses chemicals which do not increase the dissolved solids of the feedwater. One such chemical is ammonia which is dosed to give a feedwater pH of 8.8-9.6 depending upon the materials of construction, and being volatile is returned with the condensate. Polishing... 

Nuclear requirements are such that zero solids treatment is required, precluding the addition of sodium salts and necessitating the use of ammonium hydroxide for pH adjustment. 

Furthermore zero waste efforts in Brazil to avoid hazardous consequences caused by additives, due to inappropriate handling of waste, are described. The city of Cantagalo is one of the first in Brazil to establish organised separation and treatment of solid wastes for reuse. The separation with proper allocation for coprocessing of the waste not suitable for recycling or composting is a laudable solution from both an environmental and economic standpoint. 

The waste from this treatment scheme should be suitable for discharge or reuse with a possible need for removal of inorganic dissolved solids if a "zero discharge" system is used. 

In the thermolysin-catalyzed solid-to-solid dipeptide synthesis of equimolar amounts of Z-Gln-OH and H-Leu-NH2 as model substrates, the water content was varied from 0 to 600 mL water (mol substrate)-1 and enzyme concentration in the range 0.5-10 g (mol substrate)-1 to achieve 80% yield and initial rates of 5-20 mmol (s kg)-1 (Erbeldinger, 1998). When the water content is decreased from the 1.6-molal lowest substrate concentration, the initial rate increases tenfold to a pronounced optimum at 40 mL water (mol substrate)-1 and falls to much lower values in a system with no added water, and to zero in a rigorously dried system. The behavior at a higher water content was demonstrated through variation of the enzyme content to be caused by mass transfer limitations at low water levels, the effects reflect the stimulation of the enzymatic activity by water. Preheating of the substrates or ultrasonic treatment had no significant effect on the system. 

Effects of Inorganic Anions on Photocatalytic Water Treatment. Inorganic ions can significantly affect photocatalytic treatment only if they are located at the photocatalyst surface or in the Helmholtz layer. This location depends both on the chemical affinity of the ions for titania and on the point of zero charge (PZC) of this solid. 

Fig. 6. The growth of Ascites Sarcoma-180 tumor cells in untreated ICR mice (solid line) and in treated mice (dashed line). The treatment consisted of five injections of 1.5 mg kg-1 given on day 1 after inoculation of 4 000 000 tumor cells on day 0. The number of cells continues to increase by repeated cell division up to day 4 and then slowly decreases to zero cells...

Another important aspect of phase transitions in solids is the presence of soft modes. Operationally, a soft mode is a collective excitation whose frequency decreases anomalously as the transition point is reached. In second-order transitions, the soft mode frequency goes to zero at Tc, but in first-order transitions, the phase change occurs before the mode frequency goes to zero. Soft modes have been found to accompany a variety of solid-state transitions, including those of superconductors and organic solids.2,5 Occurrence of soft modes in phase transitions can be inferred from Landau s treatment wherein atomic displacements may themselves be considered to represent an order parameter. 

The early treatments of the electroreflectance effect concentrated on the case of uniform electric fields and zero thermal broadening and was therefore suitable only for very lightly doped samples at very low temperatures. The optical properties of a solid are contained in the dielectric function. This function is complex, with the imaginary part only non-zero if the material actually absorbs light. The imaginary part of the dielectric function, e2, can be written for a single band-to-band transition as [186]... 

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