Production of activated carbons from waste tire--process design and economical analysis

The process design and economic analysis of process plants to produce activated carbons from waste tires and coal have been performed. The potential range of products from each process has been considered, namely for waste tire--pyro-gas, active carbon, carbon black and pyro-oil; for coal--pyro-gas and active carbons. Sensitivity analyses have been carried out on the main process factors; these are product price, production capacity, total production cost, capital investment and the tipping fee. Net present values for the two plants at various discount factors have been determined and the internal rates of return have been determined as 27.4% and 18.9% for the waste tire plant and the coal plant, respectively.     

Prenatal diagnosis of X-linked hydrocephalus in a Chinese family with four successive affected pregnancies

We report on a woman with four successive pregnancies affected with X-linked hydrocephalus (XLH). The first child had prenatal craniocentesis and died in utero. The second child had a postnatal shunting operation, but suffers from severe growth and mental retardation at 5 years of age. In the third pregnancy, prenatal ultrasound detected hydrocephalus at the 16th and 20th weeks of gestation and the pregnancy was terminated. In the fourth pregnancy, ultrasound scanning at the 17th and 20th weeks of gestation revealed no remarkable findings, but hydrocephalus was detected at the 24th week. Autopsy confirmed the prenatal diagnosis. DNA polymorphism analysis of the Bell site of exons 17–18 of factor VIII gene of the woman and her last two fetuses seemed to be compatible with a linkage between the XLH locus and factor VIII gene. Although XLH has a variable presentation of ventriculomegaly, ultrasound scanning is still a useful tool for prenatal diagnosis at present. Earlier and more accurate prenatal diagnosis will be feasible with molecular analysis of the XLH locus or its flanking regions.     

Prenatal diagnosis and treatment of fetal long QT syndrome: a case report

We report a case of a fetus presenting with bradycardia, intermittent atrioventricular (AV) block, ventricular tachycardia (VT) and the signs of fetal congestive heart failure (ascites and scrotal hydrocele) during mid-gestation. Prenatal treatment with β-adrenergic blocker (propranolol) and digitalis glycosides was prescribed because of suspicion of long QT syndrome occurring with fetal congestive heart failure. The male baby was born at 39 weeks of gestation and showed a prolonged QT interval (QTc = 492 ms) and frequent variable AV block or alternating left and right bundle branch block, depending on the atrial rate. Prenatal administration of lidocaine failed to correct the fetal VT. Conversely, propranolol decreased the attack frequency of fetal VT. Postnatal administration of the K⁺ channel opener (nicorandil) successfully shortened the QT interval and improved the outcome. Copyright © 2002 John Wiley & Sons, Ltd.     

上下导气系统对生物反应器压实垃圾中渗滤液和填埋气迁移的影响研究

建立了2组实验室模拟填埋场生物反应器,利用上层和下层同时导排填埋气的方法,研究了填埋气和渗滤液在垃圾体中的产生和迁移情况.并在考虑渗滤液回灌的情况下,设置了C1(渗滤液回灌前加压)、C2(渗滤液回灌后加压)2组对照实验.结果表明,C1在加压后出现短暂的水位雍高现象并在第33 d后消失,而C2一直未出现水位雍高现象,上下同时导气系统能促进渗滤液和填埋气排出,#有效缓解和消除水位雍高.压力促使C1、C2的填埋气由往上迁移转变为往下迁移,C1经历了10 d的填埋气向下迁移准备期,而C2在回灌后填埋气直接往下迁移,回灌会促进孔隙通道打开,有利于气液向下排出.     

Ultrasonographic scanning of placental thickness and the prenatal diagnosis of homozygous alpha-thalassaemia 1 in the second trimester

In order to evaluate the association between placental thickness (PT) and fetal homozygous alpha-thalassaemia 1 before the appearance of classic ultrasound findings of haemoglobin (Hb) Bart's hydrops fetalis, a total of 473 pregnancies were collected. The control group included 422 normal pregnancies with a gestational age from 14 to 23 weeks and the study group included 51 affected fetuses in the same gestational period. Fetal biparietal diameter (BPD) and PT were measured by high-resolution ultrasound. PT was evaluated against BPD. In the control group, the PT generally increased in parallel with the advancement of gestational age. All PT measurements in the study group were above the mean PT of their respective gestational week in the control group. Forty-six (90 per cent) of the pregnancies in the study group had PT larger than the mean plus two standard deviations of the control group. This study suggests that ultrasound measurement of PT may be a useful aid in the prenatal diagnosis of Hb Bart's hydrops fetalis before its classic findings become apparent in the late second trimester or third trimester.     

Reducing ammonia emissions and volatile fatty acids in poultry litter with liquid aluminum chloride

This study was a pen trial in which the effects of adding different rates of liquid aluminum chloride (AlCl(3)) on litter pH, total volatile fatty acids (VFAs), and ammonia (NH(3)) fluxes was evaluated. Liquid AlCl(3) treatments used in this study were sprayed on the rice hull surface at rates of 100 g, 200 g, and 300 g liquid AlCl(3)/kg rice hulls; untreated rice hulls served as controls. Litter pH, total VFAs, and NH(3) fluxes were all lowered (P< 0.05) by all of the liquid AlCl(3) treatments compared with controls during certain times of the 5 week study. However, there were no significant differences among treatments on litter pH at the end of the study (from 3 to 5 weeks) or NH(3) fluxes at beginning of the study (0 to 3 weeks). Total VFAs were reduced 16 %, 29 %, and 53 % by 100 g liquid AlCl(3)/kg rice hulls, 200 g liquid AlCl(3)/kg rice hulls, and 300 g liquid AlCl(3)/kg rice hulls, respectively. Liquid AlCl(3)additions reduced NH(3) fluxes by 35 %, 57 % and 67 %, respectively, at the low, medium and high rates. In summary, these results indicate that adding liquid aluminum chloride to rice hulls would be a useful tool in reducing the negative environmental impact of poultry litter. It should be noted that the decreased VFA production and NH(3) volatilization was chiefly associated with reduction in litter pH.