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China has the highest incidence rate of myopia, and the number of teenagers with myopia accounts for more than half of the total number of myopia in the world. In recent years, With the increase of youth night home learning time, the impact of the night lighting environment in the home learning space on eye health has become increasingly obvious. This paper selects 112 home learning spaces of middle school students to carry out the actual measurement of lighting environment parameters and the satisfaction survey of the lighting environment, and through comparative experiments to explore the effects of illuminance, color temperature and lighting methods on eyestrain and visual efficacy. This Study found that under mixed lighting conditions, when the color temperature is 4500k, the illuminance in the range of 500lx-750lx is beneficial to relieve eyestrain and improve visual efficacy; When the illuminance is 500lx, a low color temperature (3500k) can help relieve eyestrain, and a high color temperature (6000k) can improve visual efficacy better. In addition, mixed lighting is better than local lighting for relieving eyestrain and improving visual efficacy. The results will help improve the night lighting environment in the home learning space of middle school students.

The dynamic process of the dissolution of ozone in a countercurrent bubble column is studied for model establishment. Bubble columns have been used widely for ozone contacting in the plant and laboratory. Ozone is produced by oxygen-enriched gas through an ozone generator, and introduced into the bottom of the column equipped with the gas diffuser. The ozone contacting system proceeds for a temporary and unsteady period before reaching steady state. The available ozone dissolution models employed for the description of the dissolved ozone profiles were commonly developed for the steady state. Moreover, oxygen mass transfer is usually neglected in the preceding ozone dissolution models. However, this information is desirable for proper operation of ozone dissolution in a bubble column. Thus, the objective of this study is to model and investigate the dynamic ozone dissolution process in a bubble column with the oxygen mass transfer. The dynamic axial dispersion model proposed is employed to predict the variations of ozone and oxygen concentrations along the column, and the amount of off-gas. The validity of the model is demonstrated by comparing the predicted results with the experimental data. The dynamic model of ozone dissolution is useful and referable for proper prediction of the variables of the ozone contacting system in a bubble column. DOI 10.1061/(ASCE)0733-9372(2002)128:11(1036) CE Database keywords: Ozone; Bubbles; Dynamic models; Mass transfer.

The kinetics of the ozonation of polyethylene glycol (PEG) with ultraviolet (UV) radiation in the acid-based electroplating solution of the printed wiring board industry is studied. The substrate prescription of a typical electroplating solution is with pH of 0.18-0.42, [CuS[O.sub.4] * 5[H.sub.2]O] of 200 g/L, [[H.sub.2]S[O.sub.4]] of 60 g/L, and [[Cl.sup.-]] of 0.03 g/L. Certainly, the discarded electroplating solution is hard to treat with the common chemical and biological processes because of its acidic and metallic compositions. In addition, it contains valuable substances suitable for recovery and reutilization. One of the most important processes for reviving it is to remove the aged organic additives such as PEG. A two-step reaction mechanism in terms of ozone A and total organic carbon is proposed to express the reaction kinetics of PEG ozonation with UV radiation with intensity [[I.sub.uv]]. The initial concentration of PEG is 30 mg/L, according to the recipe of a typical electroplating solution, which is equivalent to total organic carbon of 16.3 mg/L. The reaction rate r expressions of the concentrations of the liquid phase ozone [C.sub.ALb], PEG [C.sub.BLb], and intermediates [C.sub.ILb] are [r.sub.A] = -(=d[C.sub.ALb]/dt)=([k.sub.Am] + [k.sub.I][[I.sub.uv]])[C.sub.ALb] - ([k.sub.RI] + [k.sub.RI1][[I.sub.uv]])[C.sub.ALb][C.sub.BLb] - ([k.sub.R2] + [k.sub.RI2][[I.sub.uv]])[C.sub.ALb][C.sub.ILb], [r.sub.B] (=d[C.sub.BLb/dt] = -([k.sub.RI] + [k.sub.RI][[I.sub.uv]] [C.sub.ALb][C.sub.BLb], [r.sub.int] (=d[C.sub.ILb]/dt) = ([k.sub.R1]) + [k.sub.R1] [[I.sub.uv]] [C.sub.ALb][C.sub.BLb] ([k.sub.R2] + [k.sub.RI2][[I.sub.uv]])[C.sub.ALb][C.sub.ILb], with [k.sub.AM] = 0.0036 [s.sup.-1], [k.sub.I] = 4.654 x [10.sup.-5] [s.sup.-1]/(W[m.sup.-2]), [k.sub.RI], = 13.525 [M.sup.-1][s.sup.-1], [k.sub.R2] = 0.751 [M.sup.-1][s.sup.-1], [k.sub.RI1] = 0.683 [M.sup.-1][s.sup.-1]/(W[m.sup.-2]), and [k.sub.RI2] = 0.042 [M.sup.-1][s.sup.-1]/(W[m.sup.-2]). These reaction kinetic expressions are useful and referable for the proper design of an ozonation system with UV radiation for the treatment of PEG in the printed wiring board electroplating solution.

Abstract: In this investigation, the tribological performance of (Cu42Zr42Al8Ag8)99.5Si0.5 bulk metallic glass (BMG) was evaluated and compared with that of hardened S45C medium carbon steel. Three of classes of specimen were used in wear tests; they were as-cast BMG, annealed BMG and hardened S45C. Wear tests were conducted using a cylinder-on-plate Cameron-Plint TE77 reciprocating friction machine. The worn surfaces of wear specimens are observed by scanning electron microscopy (SEM), and the chemical compositions of localized regions are characterized by energy dispersive spectroscopy (EDS). The results indicate that the dominant wear mechanisms of the as-cast BMG and annealed BMG are delamination under dry sliding conditions. In contrast, the dominant wear mechanism of hardened S45C is adhesive wear. Under water-lubricated conditions, most of the worn scars are formed by abrasive wear. Although the hardness of as-cast BMG equals that of hardened S45C, the wear performance of as-cast BMG is poorer than that of hardened S45C. However, the annealed BMG exhibited the best wear performance, because of hardening by nanocrystal precipitation. This precipitation hardening effect reduces the depth of penetration by wear particles during sliding. Oil-lubricated conditions were established using three oils, and paraffin mineral (MN) base oil was found to yield the greatest wear volume for as-cast BMG. The wear loss of the as-cast BMG test in paraffin MN base oil was the highest among all of the specimens, perhaps because of tribochemical reaction wear. However, the annealed BMG exhibited excellent wear performance in paraffin MN base oil. [Copyright &y& Elsevier]

In this study, the pilot apparatus combined with sand filtration, ozonation and ultrafiltration was established. Wastewater from the secondary treatment effluent in the new-developed community was taken as the sample for looking into the feasibility of domestic wastewater reuse and recycling. The test results by sand filtration, sand filtration/ultrafiltration, sand filtration/ozonation, and sand filtration/ultrafiltration/ozonation were compared for looking for appropriate treatment processes applied in the domestic wastewater reuse and recycling. Finally, cost analysis was carried out and sand filtration/ozonation process was suggested to be one of the best processes. The total cost is about 0.1–0.32 $USD per cubic meter of produced water by considering the capital and operation cost for five years in the small domestic wastewater treatment plant (50–750 CMD). [ABSTRACT FROM AUTHOR]

This research focused on the biological treatment of high-strength organic nitrogen wastewater, and presented the results from the nitrification and denitrification of an actual industrial wastewater using anoxic/aerobic process. The opto-electronic industrial wastewater often contains a significant quantity of organic nitrogen compounds and has a ratio over 95% in organic nitrogen (Org-N) to total nitrogen (T-N). In this study, a 2-stage anoxic/aerobic process was established and evaluated the efficiency of wastewater treatment. Raw wastewater from an actual TFT-LCD manufacturing plant was obtained as the sample for looking into the feasibility of opto-electronic industrial wastewater treatment. After toxicity identification evaluation (TIE) test of raw wastewater, the inhibition was related to organic nitrogen (TMAH, MEA) and unionized ammonia (free ammonia, NH3) with high pH. Therefore, pH control is important for biological treatment of high-strength organic nitrogen industrial wastewater. Besides, hydraulic retention time (HRT) and mixed liquor recycled rate (MLR) were controlled independently to distinguish between the effects of these two factors. Under suitable HRT (>1.7 d) and mixed liquor recycled rate (<4Q), effluent of NH4-N, NO3-N + NO2-N, and COD can fall below 20 mg/L, 30 mg/L, and 80 mg/L. The anoxic/aerobic process removed 92–98% of the carbon source, and approximately 80% of TKN, 70% of T-N. [ABSTRACT FROM AUTHOR]

Explores functional improvement by adding various kinds of metallic ions in the ozonation of 2-chlorophenol solution. Reaction rate when metallic ions were added; Data indicating the best result was obtained by using manganese ions, followed by iron and titanium ions; Finding suggesting the ozone self-decomposition coefficient is highly dependent on the reaction rate constant for ozonation of 2-chlorophenol; View that the improvement of reaction was relevant to the mechanism of reaction between ozone and metallic ions; Effect of adding manganese ions.