Soil Disinfestation with Steam: A Review of Economics,Engineering, and Soil Pest Control in California Strawberry

ABSTRACT

Increasingly stricter fumigant regulations will limit their use and require effective non-fumigant treatments if large-scale strawberry production is to continue in California. Steam has long been used for soil disinfestation in greenhouse soils where it controls most soil pests. The challenge of field-scale soil disinfestation with steam in place of fumigants is availability of machinery capable of treating a large acreage in a timely manner while making the most efficient use of fuel and water. Steam can be a component within an integrated set of fumigant and non-fumigant practices. Steam used together with other practices may permit technically and economically sustainable strawberry production into the future by allowing growers to adapt to more stringent fumigant use restrictions. It may be possible to overcome some of the limitations of steam because steam generator technology has advanced in recent years as well as recent developments in co-applications with steam, including exothermic compounds co-applied with steam and mustard seed meal co-applied with steam. Regarding steam generator technology, direct-fire steam generators are more energy efficient than traditional steam boilers and avoid the hazards of steam pressure vessels. Steam is arguably the most effective non-fumigant method of soil disinfestation and it likely has a role in a future California strawberry production system that is forced to use much less fumigant than it does at present.     

龙安柚柚皮精油提取工艺及抗氧化、抑菌活性研究

本文采用水蒸气蒸馏法提取龙安柚柚皮精油,通过单因素及正交试验对提取工艺进行优化,考察浸泡时间、NaCl溶液质量分数、料液比对得率的影响;测定龙安柚柚皮精油抗氧化和抑菌活性。结果表明：当提取时间为60 min,NaCl溶液质量分数为2%,料液比为1:1.5时柚皮精油提取率最高为0.79%;龙安柚柚皮精油具有较强的还原能力和清除DPPH自由基的作用,对DPPH的半抑制浓度为3.22mg/mL,抑菌试验结果显示,龙安柚柚皮精油对大肠杆菌和金黄色葡萄球菌有一定抑制作用,随着精油浓度增加,抑菌效果增强。     

Effect of steam explosion on solid‐state fermentation of maize stalk by Penicillium decumbens and Phanerochaete chrysosporium for animal feed production

Pre‐treated maize stalk could be used for animal feed due to the improved digestibility. Steam explosion (SE) and solid‐state fermentation (SSF) are two methods in maize stalk pre‐treatment. To evaluate the effect of combination of SE and SSF on the maize stalk pre‐treatment, the maize stalk was treated with steam explosion and microbial fermentation with Penicillium decumbens and Phanerochate chrysporium in this study. The steam explosion severity (logR₀) affected component of the corn stover and then affected the SSF. The highest weight loss of substrate (23.20%), protein (12.71%) and cellulase filter paper activity (FPA) (7.42IU/g) could be obtained at logR₀ = 3.64 and the IVDMD of SE‐SSF‐treated straw could reach 75.8%. The SE‐SSF pre‐treatment method could improve the utilization of straw as animal feed and overcome the shortage of feed source in animal husbandry.     

Breaking the dormancy of rice seeds with various dormancy levels using steam and high temperature treatments in a steam nursery cabinet

This study aimed to determine the appropriate steam treatment conditions, using a steam nursery cabinet, to break the dormancy of Japanese rice cultivar seeds exhibiting various dormancy levels. The influence of the temperature and duration of the steam treatments on the germination percentage and germination rate was investigated. In highly dormant ‘Takanari’ seeds, the steam treatment at 40 °C for 7 d increased the germination percentage and decreased the 50% germination time (T_50S; based on seed number); this treatment was as effective as the dry heat treatment at 50 °C for 7 d. For the medium dormant ‘Moeminori’ and ‘Hitomebore’ seeds, the steam treatment at 40 °C for 5 d decreased T_50S sufficiently and more effectively than did the dry heat treatment at 50 °C for 7 d. For the slightly dormant ‘Moeminori’ seeds, the steam treatment at temperatures ranging from 24 °C to 40 °C for 7 d decreased T_50S without a corresponding decrease in germination percentage to <90%. For the non-dormant ‘Moeminori’ and ‘Takanari’ seeds, the same steam treatments had no, or a little if any, useful effect on the germination percentage and T_50S. Therefore, we concluded that, for the highly dormant seeds, steam treatment at 40 °C for 7 d was appropriate. Moreover, for less dormant seeds, steam treatment at 40 °C for 5 d was appropriate, and the steam treatment was not necessary for the non-dormant seeds.     

枫香树脂浅色化工艺试验

应用水蒸气蒸馏工艺,通过添加抗氧化剂,研究制备浅色化枫香树脂的方法。试验表明:对枫香脂的前处理可有效的提高枫香树脂的颜色等级,同时添加抗氧化剂也可有效防止枫香树脂在蒸馏过程中的颜色加深。适宜的工艺条件为:枫脂精油做溶解油,溶解油加入量与枫脂质量比为2∶1,蒸馏水洗4次,单次洗涤水的用量与枫脂质量比为4∶1,常压水蒸气蒸馏温度为130~140℃,蒸馏时间为30 min,减压蒸馏时间为10 min,所得枫香树脂的颜色等级由简单直接蒸馏的12(加纳级)上升为6(加纳级),软化点为131℃,酸值为53 mg/g,皂化值为104 mg KOH/g。     

关于厨房排烟排汽问题的探讨

本文论述的关于厨房排烟、排汽问题是个常见的问题。但作者借鉴国外的作法在常规的问题上提出了自己的解决方法,按我国的现有的条件、设备结合实际情况,进行了较为细致的分析。     

浅谈蒸汽锅炉管道的焊接

作者较详细的介绍了蒸汽锅炉管道焊接的全部过程和在焊接过程中经常遇到(或出现)的主要技术问题及安全注意事项。     

密闭式蒸汽冷凝水回收技术在人造板企业的应用

介绍了密闭式蒸汽冷凝水回收系统的主要原理及结构，对回收过程中存在的问题进行分析并提出了相应的解决方法，对回收系统所产生的效益和回收期进行计算。实践表明，该项技术经济和社会效益显著，具有推广应用价值。     

压缩矩形材的动态热力学分析

水蒸气处理对压缩木材变形固定和提高木材尺寸稳定性均有很好效果,水蒸气处理使压缩木内部应力释放及结晶结构增加,压缩变形得以固定(井上雅文等,1994);使压缩木内部形成凝聚结构是变形固定的主要原因(東原貴志等,2000).