Heating of the packing in a blast-furnace air heater with an internal combustion chamber

For a blast-furnace air heater, two methods of heating the packing by blast-furnace gas enriched with high-caloric fuel are analyzed on the basis of a computer model: (1) supply of the gas mixture to the air heater from a mixer; (2) separate supply of natural gas and blast-furnace gas to the air heater. Several algorithms for controlling the heating of the packing with variable calorific content of the fuel are compared. The economic benefits of each algorithm are calculated.     

考贝式热风炉拱顶空间烟气分布的数值模拟

应用大型商用计算流体力学软件CFX4·3,选用k-ε湍流模型和SI MPLE算法对新钢1200m³高炉考贝式热风炉拱顶空间内烟气分布进行了数值模拟计算.模拟结果表明:悬链线形拱顶比半球形拱顶的烟气分布均匀;在一定范围内,随着悬链线形拱顶高度的增加,在蓄热室横截面上的烟气分布趋于一定程度的均匀.     

Mathematical modeling of an aluminum casting furnace combustion chamber

A mathematical model has been developed for the combustion chambers of aluminum casting furnaces by combining the fluid flow code PHOENICS with a zone model for the radiative heat transfer analysis and a simplified flame model. It offers flexibility in specifying the size and the combustion and heat transfer characteristics of the furnace. Thus, the model can be used to study a combustion chamber under different operating conditions and for different design op-tions. This paper presents the model and describes the coupling mechanism between PHOENICS and the zone method. Various case studies have been carried out for a 72-ton melter-holder. Results are presented which show the negative effect of ambient air inleakage on furnace per-formance as an application example. T. BOURGEOIS, Formerly Graduate Student.     

考虑燃烧反应的干熄炉内一维传热模拟

建立了干熄炉内焦炭层床、循环气体的传热模型，并耦合燃烧反应计算，分析了干熄炉冷却室内的温度变化，计算结果与实测数据基本一致。还进一步分析了化学反应活化能和风料比对于熄炉内传热的影响，以期为干熄炉的优化设计提供参考。     

多孔介质燃烧技术在室式加热炉的设计与应用

介绍多孔介质燃烧技术的工作原理及多孔介质燃烧特性、多孔介质燃烧技术在一座室式炉上的应用改造方案,重点介绍了多孔介质燃烧器在室式炉上的布置设计、燃烧系统管道的设计以及多孔介质燃烧控制系统的设计。多孔介质燃烧技术在室式加热炉上的应用效果表明：多孔介质燃烧技术不仅可以提高炉温均匀性,而且节能效果显著,可以减少燃气消耗25%以上。     

3200m3 高炉外燃式热风炉炉体设计

采用外燃式热风炉技术，通过在炉壳结构、防酸处理、砌筑上采用各种措施，并依据不同使用部位的具体条件选用相应的耐火材料，以实现高风温、长寿命的目的。     

石灰套筒窑下燃烧室坍塌分析及解决方案

该文的研究不仅对环形套筒窑的成功改造,保证连续稳定生产有借鉴意义,同时也为低热值燃气的高效利用提出了新的思路和方向,为减少工业窑炉燃烧过程的污染物排放提供了一个很好的研究实例。     

高温内燃式热风炉的发展及特征

霍戈文式热风炉自1969年问世以来,迄今已在十几个国家的几十座高炉推广应用。该热风炉具有结构合理、投资省、占地少、热损失小、风温高、寿命长等优点。武汉钢铁设计研究院运用霍戈文式热风炉的设计思想,应用自己研制开发的组合砖技术成功地为武钢5号高炉和4号高炉设计了高温内燃式热风炉。现在武钢4号、5号高炉的热风炉在单烧高炉煤气的条件下平均风温达1150℃。     

The use of pimonidazole to characterise hypoxia in the internal environment of an in vivo tissue engineering chamber

The distribution of hypoxic cells in an in vivo tissue engineering chamber was investigated up to 28 days post-implantation.

Methods

Arteriovenous loops were constructed and placed into bi-valved polycarbonate chambers containing 2×10⁶ rat fibroblasts in basement membrane gel (BM gel). Chambers were inserted subcutaneously in the groin of male rats and harvested at 3 (n=6), 7 (n=6), 14 (n=4) or 28 (n=4) days. Ninety minutes before harvest, pimonidazole (60 mg/kg) was injected intraperitoneally. Chamber tissue was removed, immersion fixed, paraffin embedded, sectioned and stained immunohistochemically using hypoxyprobe-1 Mab that detects reduced pimonidazole adducts forming in cells, where pO₂<10 mmHg.

Results

At 3 days a fibrin clot/BM gel framework filled the chamber. Seeded fibroblasts had largely died. The majority of 3 day chambers did not demonstrate tissue growth from the AV loop nor was pimonidazole binding present in these chambers. In one chamber in which tissue growth had occurred strong pimonidazole binding was evident within the new tissue. In four out of six 7 day chambers a broader proliferative zone existed extending up to 0.4 mm (approximately) from the AV loop endothelium which demonstrated intense pimonidazole binding. The two remaining 7 day chambers displayed even greater tissue growth (leading edge>0.7 mm from the AV loop endothelium), but very weak or no pimonidazole binding. At 14 and 28 days the fibrin/BM gel matrix was replaced by mature vascularised connective tissue that did not bind pimonidazole.

Conclusion

Employing a tissue engineering chamber, new tissue growth extending up to 0.4 mm from the AV loop endothelium (chambers≤7 days) demonstrated intense pimonidazole binding and, therefore, hypoxia. Tissue growth greater than 0.5 mm from the AV loop endothelium (7–28 days chambers) did not exhibit pimonidazole binding due to a significant increase in the number of new blood vessels and was, therefore, adequately oxygenated.     

Transscleral ciliary sulcus fixation of a posterior chamber lens in an eye with congenital aniridia

A 30-year-old man with bilateral congenital aniridia presented with a subluxated cataract in the right eye. He wore a soft contact lens for aphakic correction in the fellow eye after lensectomy for a subluxated cataract. We performed pars plana lensectomy and vitrectomy with implantation of a transscleral ciliary sulcus fixated posterior chamber intraocular lens in the right eye. Good postoperative visual acuity was obtained.     

Simultaneous construction of an internal and external nose in an infant with arhinia

We report on the simultaneous construction of an internal and external nose in an infant born with arhinia. The indication for this very early reconstruction was due to respiratory distress and the associated feeding problems. It was possible to create two nasal cavities separated by a septum and to form an external nose from pre-expanded skin and a secondary arm flap for the tip supported by a frontal bone flap with intrinsic growth potential and auricular cartilage grafts for the tip. The 4-year-old child has excellent function of the nose with an acceptable appearance. Her psychological development is normal. Respiratory distress and associated feeding problems necessitated the use of oropharyngeal and orogastric tubes in a female infant born without a nose (arhinia). Over a period of many weeks, with attempts to remove the tube resulting in aspiration, we decided to create a functional nasal airway and an external nose simultaneously at this early stage. At the age of 20 weeks, two nasal cavities were created by using a buccal sulcus incision and connected to the existing nasopharynx and partially lined with split skin grafts. An external nose was created using the expanded midfacial skin and supporting it, an osteoperiosteal flap from the frontal bone. Later, a Tagliacozzi flap had to be added for the nasal tip. The newly constructed nose functions well and appears to aid favorably in the normal psychosocial development of the now 4-year-old girl.     

Calculation of exposure chamber leak rate with thermal correction: a measure of chamber integrity

RATIONALE AND OBJECTIVES: The authors prospectively tested the performance of a single numeric classifier constructed from a discriminative analysis classification system based on automatic computer-extracted quantitative features of clustered microcalcifications. MATERIALS AND METHODS: Mammographically detected clustered microcalcifications in patients who had been referred for biopsy were digitized at 600 dpi with an 8-bit gray scale. A software program was developed to extract features automatically from digitized images to describe the clustered microcalcifications quantitatively. The significance of these features was evaluated by using the Wilcoxon test, the Welch modified two-sample t test, and the two-sample Kolmogorov-Smirnov test. A discriminant analysis pattern recognition system was constructed to generate a single numeric classifier for each case, based on the extracted features. This system was trained on 137 archival known reference cases and its performance tested on 24 unknown prospective cases. The results were evaluated by using receiver operating characteristic analysis. RESULTS: Thirty-seven extracted parameters demonstrated a statistically significant difference between the values for the benign and for the malignant lesions. Seven independent factors were selected to construct the classifier and to evaluate the unknown prospective cases. The area under the receiver operating characteristic curve for the prospective cases was 0.88. CONCLUSION: A pattern recognition classifier based on quantitative features for clustered microcalcifications at screen-film mammography was found to perform satisfactorily. The software may be of value in the interpretation of mammographically detected microcalcifications.     

新型外燃旋流热风炉内流动与传热过程数值计算

阐明中小型高炉的风温由1000 ℃左右提高到1250-1300 ℃的主要措施是将煤气与空气双预热;提出应用高速烧嘴和新型外燃旋流热风炉来预热助燃空气,烧单一煤气可以实现高炉1250～1300 ℃高风温.对炉内流动与传热过程进行的数值计算结果表明,在蓄热球床表面没有偏流,气流及温度分布均匀.在中试炉上测量的烟气温度分布与计算结果基本吻合.     

Strength recovery in fractured sheep tibia treated with a plate or an internal fixator: an experimental study with a two-year follow-up

Lung adenocarcinoma is the most common cell type in females (smokers or non-smokers) and in non-smoking males. Its incidence has been increasing in younger cohorts of males and females until very recent years. Changes in classification and in pathological techniques account for some of this increase. In females and non-smoker males, the increase could be partly due to a detection bias in former studies. Nevertheless, successive cohorts over time seem more likely to develop adenocarcinoma and less likely to develop squamous cell carcinoma. These differences between birth cohorts suggest that the increasing incidence of adenocarcinoma is not only due to changes in pathological diagnosis. Geographical differences are also observed: in Europe, the squamous cell type still predominates and an increase in incidence of adenocarcinoma has only been reported in the Netherlands. In Asia, in the 1960s and 1970s, the proportion of adenocarcinoma was higher than in North America or Europe and seems to be increasing. To what extent these differences are due to differences. In establishing diagnosis remains unknown. Despite these biases in temporal and geographical trends detailed in this review, there has probably been a true increase in incidence of adenocarcinoma. An explanation for this should be sought in studies on detailed smoking history and passive smoking exposure, occupational exposure, diet and cooking, pollution and other environmental factors.     

高温长寿型顶燃式热风炉的应用

高温长寿型顶燃式热风炉是当今热风炉的一种新炉型,在炉型、炉衬结构及砌筑施工方法上吸取了外燃式、内燃式热风炉的优点,燃烧完全,热效率高,使用寿命长,适合大中型高炉采用.     

热风炉节能模拟系统的UML建模与分析

以UML技术和软件工程为理论依据,结合某钢铁厂的热风炉节能模拟系统开发实例,使用UML对该系统进行建模,给出了对此基于UML的热风炉节能模拟系统的分析.