The efficacy and progress in using radiation as a quarantine treatment of tropical fruits—a case study in Hawaii

Most tropical fruits for export must be treated with an approved quarantine treatment. Three and a half decades of research have demonstrated the efficacy of irradiation as a quarantine treatment in terms of efficiency, effectiveness, and product quality retention. The USFDA and the USDA-APHIS approved irradiation to disinfest fresh foods/fresh papayas in 1986 and 1989, respectively. In early 1995, the Hawaii Department of Agriculture was granted a special permit from USDA-APHIS allowing untreated Hawaiian fruits to be irradiated on the US mainland. The objectives were to gain experience in commercial irradiation as a quarantine treatment and to gather data on shipping and handling procedures, and on product quality. In April 1995, the first shipment of Hawaiian fruit was irradiated at a minimum quarantine dose of 0.25 kGy in an Isomedix plant near Chicago, and then distributed to supermarkets in Illinois and Ohio. Continuous shipments, irradiation, and marketing of various tropical fruits in the US have shown commercial efficacy, quality retention, and excellent consumer acceptance. A commercial e-beam/converted X-ray facility was installed by Titan Corp. on the Island of Hawaii and was operational by late July 2000. Hawaii has become the first place in the world to use irradiation as a quarantine treatment of fruits.     

Localization of Iα and Iβ phases in algal cellulose revealed by acid treatments

Highly crystalline I-rich type Cladophora cellulose, which had been kept in never-dried condition, was treated in 60wt% sulfuric acid at 100°C, for 1–48h. The cellulose microcrystals thus obtained were analysed by X-ray diffractometry, FT-IR, and transmission electron microscopy. The I component was found to be more degraded than the I component. The cellulose I/I ratios of the samples acid-treated for 0, 24, and 48 h were about 8:2, 6:4, and 4:6, respectively. After the acid treatment, the microcrystals became narrower in width, and very sharp at their ends. These results indicate that the I phase is mostly located at the surface of the microcrystals, which is morphologically more susceptible to the acid treatment.     

Performance of an internal-loop airlift bioreactor for treatment of hexane-contaminated air

Hexane is a toxic volatile organic compound that is quite abundant in gas emissions from chemical industries and printing press and painting centers, and it is necessary to treat these airstreams before they discharge into the atmosphere. This article presents a treatment for hexane-contaminated air in steady-state conditions using an internal-loop airlift bioreactor inoculated with a Pseudomonas aeruginosa strain. Bioprocesses were conducted at 20-mL/min, a load of 1.26 g/m³ of C₆H₁₄, and a temperature of 28°C. The results of hexane removal efficiencies were presented as a function of the inoculum size (approx 0.07 and 0.2 g/L) and cell reuse. Bioprocess monitoring comprises quantification of the biomass, the surface tension of the medium, and the hexane concentration in the fermentation medium as well as in the inlet and outlet airstreams. The steady-state results suggest that the variation in inoculum size from 0.07 to 0.2 g/L promotes hexane abatement from the influent from 65 to 85%, respectively. Total hydrocarbon removal from the waste gas was achieved during experiments conducted using reused cells at an initial microbial concentration of 0.2 g/L.     

Environmental and economic comparison of waste solvent treatment options

The sustainable development and consumption need more efficient use of natural resources. As a consequence, the use of industrial solvents demands their recovery instead of end-of-pipe treatment. It is not always clear, however, which treatment alternative should be applied. Based on an industrial case study, the environmental and economic evaluation and comparison of the treatment alternatives of a non-ideal solvent mixture containing azeotropes is investigated for determining the preferable option. For the recovery of the industrial solvent mixture, two different separation alternatives are evaluated: a less effective alternative and a novel design based on hybrid separation tools. An end-of-pipe treatment alternative, incineration, is also considered and the split of the solvent mixtures between recovery and incineration is investigated. The environmental evaluation of the alternatives is carried out using ‘Eco-indicator 99 life-cycle impact assessment methodology’. Economic investigation is also accomplished. The economic features clearly favour the total recovery, however, the environmental evaluation detects that if a recovery process of low efficiency is applied, its environmental burden can be similar or even higher than that of the incineration. This motivates engineers to design more effective recovery processes and reconsider the evaluation of process alternatives at environmental decision making.     

微量元素锌在治疗Bell麻痹中的作用

为探讨急性早期应用补锌和综合疗法治疗Bell麻痹 ,将 1 5 8例Bell麻痹患者 ,随机分成两组 :(1 )补锌组 (补锌 +综合疗法 ) ;(2 )对照组 (单纯综合疗法 )。对其进行了观察对比治疗 ,同时检测了所有患者治疗前后自身对照发锌值 ,还对所有患者进行了定位诊断、面神经电反应测试、并对面肌功能进行评分。结果表明 ,对定位诊断其病变在D段、面肌功能评分在 1 1分以下、面神经无电反应患者 ,即使给予早期综合治疗 ,效果仍较差 ,而早期给予补锌加综合治疗效果优于对照组 ,其它段内患者治疗次数和治愈天数也均优于对照组。可见微量元素锌在发挥免疫应答、免疫调控中的重要作用     

Surface characterization of cellulose fibres by XPS and inverse gas chromatography

Inverse gas chromatography (IGC) was used to determine the dispersive component of the free energy as well as the acid-base properties of cellulose fibre surfaces, before and after modification by corona treatment. It was found that the corona treatment increases both the dispersive contribution to surface energy and its acidic character, whereas only a slight increase in its basicity was observed. It was also found that some chemical degradation of the surface occurs at high corona currents. The extent of modification of the surface properties, as revealed by IGC, was correlated to the surface chemical composition deduced from XPS analysis as well as with the electrical conductance and the pH of the water suspensions of the cellulose fibres.     

Determination of heavy metal concentration in feed and permeate streams of polymer enhanced ultrafiltration process

Polymer enhanced ultrafiltration (PEUF) is a newly developed method for the removal of heavy metals from aqueous solutions. This method was applied for the removal of mercury and cadmium with the presence of polyethyleneimine (PEI) as a water soluble polymer. After ultrafiltration experiments for metal–polymer mixtures, two separate streams, namely, retentate and permeate, former of which contains mainly metal–polymer complex and free polymer molecules while latter of which mainly contains free metal ions, were obtained. At the end of PEUF experiments, performance of operation was determined by concentration analyses which was achieved by atomic absorption spectroscopy (AAS) applied in a different way for permeate and retentate streams considering the effect of presence of polymer. For mercury analysis, cold vapor AAS was applied. It was observed that the presence of PEI did not affect the atomic absorption signal when 10% HCl was added to the sample solutions. For calcium and cadmium, flame AAS was used. It was observed that change in PEI concentration results in change in measured concentration of calcium and cadmium. Therefore, two new approaches were developed for accurate measurement of concentrations of calcium and cadmium. It was also observed that presence of other metals did not affect the accuracy of the measurement of a particular metal in the concentration range studied.     

笼形聚偕胺肟树脂的研究—酚处理对树脂吸附贵金属性能的影响

研究了笼形聚偕胺肟树脂（CAO）和酸式（ACAO）及碱式（BCAO）树脂对于苯酚、对-氨基酚、对-硝基酚、对-甲氨基酚和对-苯二酚的吸附和吸留作用，测定了酚处理树脂的中和当量。它反映了笼形树脂吸留外来物的特性。酚处理树脂有效地吸附Ag 、AuCl4－、PtCl62-、PdCl42-和IrCl62-等贵金属离子，吸附方式似乎与溶液的pH值有关。SEM观察表明，Ag 、Au－Cl4-和IrCl62-离子在吸附过程中被还原为零价态，在树脂表面生成形态各异的结晶。     

Interaction of long chain alkylammonium cations with reduced charge montmorillonite

Reduced charge montmorillonites (RCM) were prepared using lithium thermal treatment. The sorption of octylammonium (OA), dodecylammonium (DDA) and hexadecylammonium ions (HDA) on differently charged samples were studied. The amounts of DDA and HDA sorbed on each RCM exceed the cation exchange capacity (CEC) but that of OA exceeds only the CEC of samples with the lowest CEC. The sorption is affected not only by the layer charge but also by the formation of collapsed interlayer spaces in the lowest charged montmorillonites. X-ray measurements confirmed the decrease of the layer charge after lithium thermal treatment and the layer charge heterogeneity in RCMs.     

笼形聚偕胺肟树脂的研究─—H_2PtCl_6在酸处理树脂上的吸附过程

H2PtCl6可被一系列的酸处理定形聚偕胺肟树脂所吸附，吸附容量的大小与处理树脂的质子酸的Pka值有关．认为是解高度低的酸所处理的树脂上的伯胺基成盐的机会较少，即树脂的吸附中心保留着较多的空穴，有利于H2PtCl6的接近而被吸附下来．吸附动力学的研究表明化学反应是吸附速度的控制因素。