New monitoring concept of moisture content distribution in wood during RF/vacuum drying

A new method for monitoring moisture content during radio-frequency (RF)/vacuum drying was developed by measurement of temperature and pressure in wood. Temperature and pressure inside the wood were measured simultaneously during RF/vacuum drying at the same point. The relative humidity (RH) and moisture content (MC) below the fiber saturation point (FSP) were calculated based on temperature and pressure, and the relationship between the temperature, RH, and equilibrium moisture content (EMC) at the measurement point. When the moisture content was below the FSP, the calculated MC was slightly greater than the value given by oven drying. The absolute error was within 0.8% near the open cross side, and was within 1.8% at another measurement point. Thus, we concluded that it was practicable to monitor the moisture content below the FSP according to the temperature and pressure inside the wood. Part of this study was presented at the 15th Annual Meeting of the Chugoku Shikoku Branch of the Japan Wood Research Society, Higashi-Hiroshima, Japan, September 2003     

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin I: effects of pressing pressure and pressure holding

The deformation behavior of low molecular weight phenol formaldehyde (PF) resin-impregnated wood under compression in the radial direction was investigated for obtaining high-strength wood at low pressing pressures. Flat-sawn grain Japanese cedar (Cryptomeria japonica) blocks with a density of 0.34g/cm³ were treated with aqueous solution of 20% low molecular weight PF resin resulting in weight gain of 60.8%. Oven-dried specimens were compressed using hot plates fixed to a testing machine. The temperature was 150°C and the pressing speed was 5mm/min. The impregnation of PF resin caused significant softening of the cell walls resulting in collapse at low pressures. The cell wall collapse was strain-dependent and occurred at a strain of 0.05–0.06mm/mm regardless of whether the wood was treated with PF resin. Thus, pressure holding causing creep deformation of the cell walls was also effective in initiating cell wall collapse at low pressure. Utilizing a combination of low molecular weight PF resin impregnation and pressure holding at 2MPa resulted in a density increase of PF resin-treated wood from 0.45 to 1.1g/cm³. At the same time, the Youngs modulus and bending strength increased from 10GPa to 22GPa and 80MPa to 250MPa, respectively. It can be concluded that effective utilization of the collapse region of the cell wall is a desirable method for obtaining high-strength PF resin-impregnated wood at low pressing pressures.     

Termite resistance and wood-penetrability of chemically modified tannin and tannin-copper complexes as wood preservatives

We examined the ability of chemically modified tannin and tannin-copper complexes to penetrate wood and the ability of the treated wood to resist termites. Only the tannin-treated wood retained the agents after treatment. Wood with untreated mimosa tannin (MT) retained the least amount, followed by wood with resorcinolated tannin (RMT) and that with catecholated tannin (CMT). When RMT or CMT was mixed with ammonia-copper, the wood retained twice as much of these solutions as the MT -ammonia-copper solution. The degree of retention of RMT-NH₃-Cu and CMT-NH₃-Cu ranged from 268 to 326kg/m³. The solutions penetrated 2–13 mm from the tangential sections of the logs. We also measured the termite resistance conferred by these solutions. Most of the tannin-NH₃-Cu solutions showed contact lethality for termites in the contact toxicity test. However, the termites were fed cellulose treated with those solutions and most survived the oral toxicity test (14 days). Moreover, these solutions reduced the amount of damage to the wood by termites. However, the mortality rate of the termites during the eating-damage test (>21 days) did not reach 100% for any of the solutions except for RMT. As a result of the field stake test with the same log's used for the penetrability test, the mass loss of wood treated with RMT or CMT alone or with RMT + NH₃ + CuCl₂, was about one-third to one-half that of the controls. Because these solutions have good wood penetrability and good termite resistance, they have potential use as low-toxicity wood preservatives.     

缺铁失绿秋白梨树强力树干注射铁肥的效果初报

果树缺铁失绿是果树生产上的一种重要营养失调症。本文报道了向缺铁失绿秋白梨树树干强力注射不同剂量硫酸亚铁矫治缺铁失绿的效果。注铁后10天开始复绿;至43天,不同注铁处理都有一定程度复绿,其中剂量≥6克/株的处理最好,失绿完全消失并且一直持续到秋季休眠落叶。不同注铁处理使叶片叶绿素和叶子铁（Fe）含量显著增加,并对叶片结构有明显的修复作用。通过与其它已有的缺铁矫治技术相比较,强力树干注射铁肥法是一个简便易引,高效、速效而且经济的新途径。     

阶梯隔舌对离心泵压力脉动和径向力影响的数值模拟

通过改变隔舌形状,采用SST模型分别对常规隔舌和阶梯隔舌蜗壳的离心泵进行全流道非稳态数值模拟。通过模拟分别获得了常规隔舌和阶梯隔舌蜗壳的离心泵压力脉动特性、作用在蜗壳和叶轮上的径向力特性,并对其进行比较分析。结果表明：采用常规隔舌和阶梯隔舌时,离心泵进出口压力、作用在蜗壳和叶轮上的径向力均随时间呈周期波动,脉动频率均以叶片通过频率为主;采用阶梯隔舌蜗壳后,进出口压力大小值和脉动幅值均明显减弱,高频脉动成分减少,作用在蜗壳上的径向力数值和脉动幅值也减小;作用在叶轮上的径向力大小和方向时刻都在变化,且整体变化趋势基本呈圆形分布。     

Effect of pressure on organic acid production from Japanese beech treated in supercritical water

The effect of pressure as described by density was studied on organic acid production from Japanese beech (Fagus crenata) treated in supercritical water. At a reaction temperature of 380°C, the maximum yield of organic acids was 35% at a pressure of 30 MPa (density of water: 0.53 g/ml) for 1 min in a batch-type system. Furthermore, the yield of organic acids decreased with increasing reaction pressure. It was also found that fragmented products from sugars such as methylglyoxal and glycolaldehyde could be more easily converted to organic acids than dehydrated products such as furfural and 5-hydroxymethyl furfural. This result suggests that organic acids can be mainly derived from fragmented products. Part of this article was presented at the 55th Annual Meeting of the Japan Wood Research Society (2005), and at the 17th Annual Meeting of Japan Institute of Energy (2007)     

GPS掩星数据反演中由大气折射率反演温度和气压的误差分析

介绍了几何光学的反演方法.通过对GPS/MET和CHAMP掩星数据反演结果的分析,讨论了由大气折射率反演温度和气压时,把某一高度的重力加速度看作定值放在积分外和把重力加速度看作变量放在积分内两种方法计算结果上的差异,并说明了两种方法对GPS/MET和CHAMP数据反演精度的不同影响.     

调压灌溉系统压力变幅对应关系的研究

建立调压灌溉系统各部分压力变幅的对应关系是合理确定调节压力限的基础。通过管网各节点压力变量的分析及建立水泵机组供水扬程与调压罐压力平衡之间的关系,提出了田间压力变幅、水泵扬程变幅与调压罐压力、水位变幅的直接对应关系,据此可很简便地根据田间灌水质量所要求的田间压力允许变幅及水泵机组经济安全运行所允许的扬程变幅,综合确定调压罐的调节压力限。     

Year-to-year variations in Bering Sea ice cover and some consequences for fish distributions

The southernmost extension of winter ice cover varies interannually and on longer time scales, reflecting large-scale changes in driving forces, especially in the position and intensity of the winter Aleutian Low Pressure System. A conspicuous pattern is alternating warm and cool periods of several years' duration. These variations in sea ice cover are reflected in the character of a subsurface cold pool, formed as stratification isolates the deeper cold waters from surface exchanges. The cold pool is better developed and more extensive in summers that follow deep southward penetration of winter sea ice. Interannual and decadal-scale variations in the distributions of some fish stocks reflect those of ice and thermal conditions. In particular, the distribution of walleye pollock, Theragra chalcogramma, varies significantly with multiannual cool and warm years while Arctic cod, Boreogadus saida, is only present within the cold pool. The relation among climate variations, sea ice cover, subsurface thermal conditions, and fish distribution provides information on how climate affects marine ecosystems and may also have practical application in predicting fish distributions.     

Zacopride attenuates pressure overload-induced ventricular remodeling in rats

AIM:To investigate the protective effect of zacopride (ZAC) on the pressure-overload left ventricular remodeling in the rats induced by coarctation of abdominal aorta. METHODS:Male Sprague-Dawley (SD) rats with pressure overload were induced by the coarctation of abdominal aorta. The model rats were intraperitoneally administered with ZAC, chloroquine (Chlor), and zacopride+chlorquine (ZAC+Chlor). The study duration was 8 weeks. The cardiac structure and function were assessed by echocardiography. The heart weight/body weight (HW/BW) ratio and the left ventricular weight/body weight (LVW/BW) ratio were calculated. The changes of structure and shape in myocardial tissue were observed with HE staining. The ultrastructure of the myocytes was observed under transmission electron microscope. The inward rectifier potassium channel (I_K1) protein expression was determined by Western blot. The mRNA expression of Kir2.1 was detected by RT-PCR. RESULTS:Compared with vehicle group, ZAC improved cardiac function, as indicated by the decreased left ventricular end-diastolic dimension (LVEDD) and left ventricular end systolic dimension (LVESD) (P<0.05), and the increased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) (P<0.01). The HW/BW and LVW/BW ratios were significantly decreased, and the cross-sectional area of the cardiomyocytes was significantly less in ZAC group than that in vehicle group (P<0.01). The ultrastructure of the myocytes was significantly improved. Chlor blocked the protective effect of zacopride on the pressure-overload left ventricular remodeling. The protein level of I_K1 and mRNA expression of Kir2.1 in the cardiac tissues in ZAC group were significantly increased compared with vehicle group (P<0.01). CONCLUSION:I_K1 agonist ZAC significantly attenuates pressure overload-induced ventricular remodeling in rats.