Practical Method to Prevent Liquid-Column Separation

This paper describes a practical method to prevent the phenomenon of liquid-column separation in a pipeline by increasing the polar moment of inertia of the rotating parts of a pump-motor unit. Two examples are presented in detail. The examples indicate the following advantages of this method over other methods (e.g., installing air valves, air vessels, or one-way surge tanks in a pipeline): (1) low in cost for small-capacity motors; (2) safe and reliable; (3) not limited by conveyed media and climates; (4) no additional maintenance required; and (5) applicable to any pumping projects when the size and weight of motors are not limited in manufacture.     

Iatrogenic air embolism

The incidence of iatrogenic air embolism can only be estimated since many accidents are not recognized. Clinical manifestations, essentially neurological or cardiovascular disorders vary greatly. Air embolism may occur during coronary or cerebral arteriography, cardiopulmonary bypass, venous catheterism, various types of surgery or blood transfusion among other situations. Once air has entered the arterial circulation, the bubble of gas follows the blood flow until it is blocked by a smaller calibre vessel. The progressive diffusion of the air reduces the size of the embolus which then migrates on to smaller and smaller vessels. Subsequent pathological manifestations of air embolism result from mechanical obstruction leading to ischemia and inflammatory reactions to air acting as a foreign body. The sudden onset signs of neurological impairment with or without a cardiopulmonary component in patients in a high-risk situation leads to clinical diagnosis. Treatment must be started immediately although brain CT scan or echocardiography may help confirm the diagnosis. The source of the air must be immediately identified and removed and the vital functions controlled. Mechanical or facial mask ventilation with pure oxygen is indicated. Hyperbaric oxygen therapy should be instituted. Morbidity and mortality after iatrogenic air embolism is high but major improvements have been achieved with oxygen therapy. Neurological sequellae have been estimated to reach 19 to 50% of the patients. A personal controlled prospective study revealed 14% mortality after hyperbaric oxygen therapy given within 12 hours of the accident.     

Role of astrocytes in the control of developing retinal vessels

PURPOSE: To assess the role of astrocytes in controlling the growth of developing retinal vessels. METHODS: Growth of retinal vessels in the neonatal rat retina was examined in three conditions: normal development, cyclic hyperoxia, and normoxia (1 day 70% to 75% oxygen, 1 day room air for up to seven cycles from birth, and room air for up to 16 days), and direct hypoxia (10% oxygen from postnatal day 3 [P3]). Retinas were examined as wholemounts labeled for astrocytes, microglia, and blood vessels and in some experiments for the fragmentation of DNA characteristic of apoptosis. RESULTS: In normoxia, superficial retinal vessels formed to the processes of astrocytes. In cyclic hyperoxia, the depletion of superficial retinal vessels and subsequent neovascularization described by others were confirmed. The neovascularization was preceded by the depletion by apoptotic death of the astrocyte population, first between vessels but eventually breaching the glia limitans along vessels. The earliest forms of neovascularization resembled microaneurysms, each protruding through a defect in the glia limitans of a capillary. Neurons of the ganglion cell layer survived. Direct hypoxia from P3 caused hypertrophy of superficial vessels. Between P3 and P6, some vessels accelerated past the still-spreading astrocytes, often growing out of the retina into the vitreous humor. Direct hypoxia also caused astrocyte degeneration, but capillaries retained astrocyte investment and were not the site of vascular damage. By P8, breaches in the astrocytic glia limitans became prominent but were restricted to large veins. At such breaches, bleeding into the vitreous humor was common. CONCLUSIONS: Retinal vessels normally develop in close association with astrocytes. Where that association is broken, preretinal vessels may grow or bleed into the vitreous humor. Astrocytes play important roles in constraining retinal vessels to the retina and in maintaining their integrity.     

Effect of continuous melatonin infusions on steady-state plasma melatonin levels in rats under near physiological conditions

Over one hundred cases of legionnaires' disease have been linked to ships, and ten cases are known to have died. Most of the cases were associated with cruise ships, but a variety of other vessels were also linked to cases. Few vessels were investigated microbiologically, and the cases associated with ferries were exposed to other sources of infection. Cases appear to be less common among crew members than among passengers. To prevent further cases, ship owners, operators, and captains need to be diligent in maintaining the water and air conditioning systems of their vessels. Whirlpool spas need particular care. Ship-associated cases of non-pneumonic legionellosis appear to be rare.     

Vascular enumeration as a significant prognosticator for invasive breast carcinoma

PURPOSE: Vascular enumeration has been claimed to be an independent prognosticator for invasive breast cancer. Most of the studies have performed a manual count of the vessels. Few investigators have used image analyzers to reduce subjectivity in the measures. The aim of this retrospective study was to compare the manual vessel count to the counts obtained with an image analyzer and to estimate their possible prognostic influence. MATERIALS AND METHODS: We selected 112 patients with invasive ductal carcinoma, treated with radical mastectomy followed by chemotherapy and with a minimal follow-up time of 60 months (5 years). After immunostaining with factor VIII, we performed a double count of the vessels. First, we performed a manual count following Gasparini's criteria, and second, we used an image analyzer (Microm, Barcelona, Spain) to count the vessels in eight adjacent microscopic fields with a 20x objective, to reach a total area of 0.98 mm2. The image analyzer calculated the total number of vessels, their size and also the percentage of the field occupied by the vessels. RESULTS: In our series, vascular enumeration showed no significant association with histologic grade (Bloom-Scarff-Richardson grading), tumor size, or staging. CONCLUSION: Vascular enumeration with both methods was an independent prognosticator for relapse-free-survival (RFS) in both node-negative and -positive patients in the univariate analysis, but only vascular enumeration with the image analyzer was an independent prognostic factor in the multivariate analysis, together with lymph node metastases.     

Local vacuum electron beam welding for pressure vessel applications

Welding of thick section components such as pressure vessels used in the nuclear industry is traditionally performed using arc welding techniques, requiring multiple weld passes, with interstage non-destructive examination (NDE) and preheating of the component to reduce the risk of hydrogen cracking. Electron beam (EB) welding offers the opportunity to weld thick section components in a single pass and negates the need for interstage NDE, resulting in saving significant time and cost in the fabrication of nuclear vessels. Furthermore, elimination of the preheat step may be possible since the EB process is carried out in a vacuum environment. However, due to the physical size and geometry of nuclear vessels, traditional vacuum chambers would be prohibitively expensive when considering the low volume of output in the nuclear industry. Rolls-Royce and TWI are working on a local vacuum, or ‘out of chamber’, EB welding system, which eliminates the need of such a vacuum chamber and brings the vacuum to the component, thus making EB welding of nuclear vessels more practical and financially viable.     

A flexible algorithm for construction of 3-D vessel networks for use in thermal modeling

A new algorithm for the construction of artificial blood vessel networks is presented. The algorithm produces three-dimensional (3-D) geometrical representations of both arterial and venous networks. The key ingredient of the algorithm is a 3-D potential function defined in the tissue volume. This potential function controls the paths by which points are connected to existing vessels, thereby producing new vessel segments. The potential function has no physiological interpretation, but, by adjustment of parameters governing the potential, it is possible to produce networks that have physiologically meaningful geometrical properties. If desired, the veins can be generated counter current to the arteries. Furthermore, the potential function allows fashioning of the networks to the presence of bone or air cavities. The resulting networks can be used for thermal simulations of hyperthermia treatment.     

Estimation of vascular blood flow velocity in the breast neoplasms

Based on examinations of 133 females having the normal breast, benign and malignant tumors, the potentialities of color Doppler mapping of breast vessels are shown. Cancers showed an increased vascularity in the peritumor areas and high flow velocity (Vmax' Vmean) in the surrounding tumor vessels. These criteria are not related to the size of a malignant tumor.     

Roles of vascular endothelial growth factor and astrocyte degeneration in the genesis of retinopathy of prematurity

PURPOSE: To assess the role of vascular endothelial growth factor (VEGF) in the feline model of retinopathy of prematurity (ROP). METHODS: Retinopathy of prematurity was induced in neonatal cats by raising them in an oxygen-enriched (70% to 80%) atmosphere for 4 days to suppress vessel formation and then returning them to room air for 3 to 27 days. In situ hybridization was used to detect the expression of VEGF and its high-affinity receptor, flk-1, in the retina of neonatal cats, and glial fibrillary acidic protein immunocytochemistry was used to assess astrocyte status. RESULTS: The expression of VEGF in the innermost layers of retina fell in hyperoxia and increased on return to room air. Vascular endothelial growth factor expression was transient; it was maximal where vessels were about to form, and it rapidly downregulated after vessels had formed. During the proliferative vasculopathy of ROP, VEGF expression was stronger than in the normally developing retina, and the astrocytes that normally express VEGF degenerated. After the degeneration of astrocytes, VEGF was expressed by neurones of the ganglion cell layer. flk-1 was expressed by intraretinal and preretinal vessels. Supplemental oxygen therapy reduced or eliminated the overexpression of VEGF expression, astrocyte degeneration, and formation of preretinal vessels. CONCLUSIONS: Regulation of VEGF by tissue oxygen mediates the inhibition of vessel growth during hyperoxia and the subsequent proliferative vasculopathy. Degeneration of retinal astrocytes creates conditions for the growth of preretinal vessels.     

Fiberoptic transillumination: a new tool for the pediatric surgeon

Transillumination (TI) is a safe and reliable technique for evaluating masses or the presence of free air in the thorax or abdomen. TI can also be of help in the accurate placement of catheters or needles in the chest, abdomen, bladder, or vessels. Its use in several hundred cases has been documented by this report.     

Remodeling of alveolar walls after elastase treatment of hamsters. Results of elastin and collagen mRNA in situ hybridization

Treatment of hamster lungs with porcine pancreatic elastase (PPE) causes emphysema and a decrease in lung elastin content, which returns to control level by Day 30. To explore the mechanism of alveolar wall remodeling after elastolytic injury, we examined the expression of elastin and alpha1(I) collagen mRNAs by in situ hybridization at 1, 2, 3, 5, 7, and 30 d after intratracheal PPE. The lungs of control animals displayed weak signals for elastin and alpha1(I) collagen mRNA in pleura, large arteries, veins, and airways. There was little or no signal in respiratory air space walls. Increased expression of elastin and alpha1(I) collagen mRNA began by Day 1 after PPE and reached an asymptote by Day 3 that was maintained by elastin until Day 7; expression of alpha1(I) collagen mRNA waned earlier. Elastin and, to a lesser extent, alpha1(I) collagen mRNA were heavily expressed in pleura, blood vessels, and airways. Analysis of serial sections showed elastin message was minimal in the walls of respiratory air spaces and when present, at 3, 5, and 7 d, was primarily found at the free margins of alveolar septa. Collagen message was very sparse in respiratory air space walls. By 30 d, elastin mRNA expression was reduced but still above control levels and emphysema was widespread and severe. Rank score of elastin mRNA expression in individual subpleural air spaces showed a positive correlation with air space size. In conclusion, most expression of elastin and alpha1(I) collagen mRNA occurs in the pleura, airway, and vascular walls. In respiratory air space walls, expression of elastin mRNAs occurs in damaged tissue at free septal margins.     

Environmental effects on the creep behavior of a nickel-base superalloy

Environmental effects on the 760 °C creep behavior of a nickel-base superalloy are isolated by testing at varying stress levels, in laboratory air and vacuum, specimens of different gage diameters and grain sizes, and in a few cases, different grain boundary microstructures. For all specimens receiving a standard heat treatment that results in grain boundaries free of discrete carbides, the minimum creep rate is greater in air than in vacuum for a given specimen and grain size. In contrast, for specimens aged to precipitate carbides along the grain boundaries, the creep rate is lower in air than in vacuum. The minimum creep rate and the sensitivity of this rate to applied stress also are found to be functions of grain size, specimen size, and grain boundary microstructure to extents dependent on the test environments. Rationalizations of these environmental creep behaviors are suggested in terms of the apparently competing phenomena of the relative weakening of the alloy grain boundaries in the air environment, and the alloy creep strengthening in air due to the external surface oxide scale. Formerly Graduate Research Assistant, Henry Krumb School of Mines, Columbia University     

Innovative System for Off-the-Ground Rotation of Long Objects Using Mobile Cranes

Managing heavy-pressure vessel lifts on construction sites requires planning, arranging adequate crane support, and preparing collision-free rotation (from a horizontal position to a vertical position) of the vessel. Generally, selecting mobile cranes and developing engineered lift studies for vessels are done using two cranes and analyzing the lift for each crane individually on the basis of the selected cranes’ lift-capacity specifications provided by crane manufactures. This practice is relatively costly and time-consuming. Optimizing the mobile cranes’ use and location is also difficult. To assist in the field operation of mobile cranes and to provide engineers with a planning tool, this paper presents a methodology to carry out such a lift utilizing only one crane. Using the developed methodology and mechanism, heavy vessels can be rotated off the ground (in the air) with one crane. The proposed mechanism is supported with a mathematical model that has been developed into a computer system and has been integrated with a previously developed crane selection and ground pressure calculation system and crane database. The developed system provides users with a lift study analysis for a given configuration as well as simulation results with interactive graphics to assist in the selection of an optimum configuration. This research is important as projects involving heavy lifts need to reduce the cost and time associated with construction operations.     

中厚板中间冷却工艺的研究及应用

 中厚板生产过程中采用中间冷却（IC）工艺可以增加待温过程的冷却速率,提高轧制效率。采用有限元方法分析了中间坯待温过程的温度场变化,结果表明：通过中间冷却结合40～60s的空冷返红时间,冷却效果与完全空冷基本相同;通过热模拟试验的方法研究了中间冷却过程中的晶粒尺寸的变化规律,分析了中厚板冷却过程中晶粒长大的控制方法,将中间冷却工艺应用于国内某中板生产线,有效提高了生产效率,改善了表面质量并能降低合金成分的添加量。     

Neural-Net–Based Predictive Modeling of Spout Eye Size in Steelmaking

Gas stirring is commonly used in pyrometallurgical vessels to enhance mass and heat transfer and to promote impurity removal. In the case of secondary steelmaking, the spout eye area is caused by the escape of the gas from the top of the smelt where the liquid steel is directly exposed to the air, and oxygen can be picked up through the spout eye area that can reduce the quality of steel. Thus, controlling the size of the spout eye area is very important to improving the quality of the steel and to keeping the consistency of the product. The set of prevailing models to predict spout eye size are based on specific practically difficult variables, e.g., height of slag in hot upper layer of vessels and gas flow rate at nozzle exit. Recently, the cold model results showed that the stirring process can be conveniently monitored by the signals such as (1) the image signal from the top of the vessel, (2) the sound of the stirring process, and (3) the vibration on the wall of the vessel. This article outlines the key details of a novel research investigation using neural-network?Cbased predictive modeling such as general regression neural networks (GRNN) with genetic adaptive calibrations. Predictive capacities and generalization potentials of five model constructs (i.e., with different sets of input parameters) were explored, and the neural net modeling yielded encouraging outcomes, e.g., (1) excellent goodness-of-fit generalization measures including high values of correlation and R ² validation parameters (e.g., r?=?0.921 and R ²?=?0.845 in a model validation), and (2) low values of root mean square of errors (e.g., 3.034). Overall, the research outlined in this article demonstrates that the spout eye size can be effectively predicted by predictive neural net modeling with convenient and practically measurable variables such as sound and vibration observations on the steelmaking vessels. These results have only been demonstrated for a cold model of the process, and further work is required to show that this approach can be extended to industrial operations.     

Modeling Immune Building Systems for Bioterrorism Defense

This paper presents the results of research on the performance of air-cleaning and air-disinfection systems used for protecting buildings against intentional releases of biological agents. The air-cleaning technologies addressed include dilution ventilation, filtration, and ultraviolet germicidal irradiation. A 40-story commercial office building is modeled using typical occupancy levels and leakage rates for doors, walls, and floors. A steady-state single-zone model is used to predict steady-state conditions resulting from the use of various levels of air cleaning. A transient single-zone model is used to predict transient indoor concentrations from which inhaled doses and estimated casualties are predicted. A transient multizone model is used to evaluate contaminant dispersion and estimate potential casualties. Three design-basis attack scenarios are simulated using various biological weapon agents. Predicted casualties are estimated using an epidemiological model of the dose response curves for each of the agents. The effect of increasing levels of air cleaning is examined under the attack scenarios to evaluate their effectiveness. Results indicate that high levels of protection are possible for building occupants with moderate and affordable levels of air cleaning when filtration is combined with ultraviolet germicidal irradiation. Results also suggest that diminishing returns occur when increased levels of air cleaning are applied. It is hypothesized that the maximum useful size of any air-cleaning system is defined and limited by building physical characteristics alone.     

Mechanochemical Effects in Ln_2O_3-Ln(OH)_3-(H_2O)(Ln=La,Nd) System

ＭｅｃｈａｎｏｃｈｅｍｉｃａｌＥｆｅｃｔｓｉｎＬｎ２Ｏ３Ｌｎ（ＯＨ）３（Ｈ２Ｏ）（Ｌｎ＝Ｌａ，Ｎｄ）ＳｙｓｔｅｍＤｉｍｉｔｒＴｏｄｏｒｏｖｓｋｙ，ＡｔａｎａｓＴｅｒｚｉｅｖ（ＦａｃｕｌｔｙｏｆＣｈｅｍｉｓｔｒｙ，ＵｎｉｖｅｒｓｉｔｙｏｆＳｏｆｉａ...     

非调质钢中MnS的析出与长大

摘要：在立式电阻炉内熔化45MnVS钢,分析了水冷和空冷2种冷却方式下试样中MnS的形貌特征,并对试样中MnS的析出与长大进行了热力学和动力学计算。结果表明：水冷试样中MnS的平均尺寸为1.14μm,最大尺寸为7.80μm;空冷试样中MnS的平均尺寸为2.19μm,最大尺寸为8.78μm。钢液凝固过程中,MnS在固相分率达到0.69时析出;在相同固相分率下,水冷试样比空冷试样中MnS的尺寸小。固相分率小于0.97时,S元素为MnS长大的控制元素,固相分率大于0.97时,Mn元素为MnS长大的控制元素。计算所得水冷试样和空冷试样中MnS最终尺寸分别为5.27和9.54μm。     

Guidelines for the Design of Multiple-Use Explosion Containment Vessels Based on the Understanding of the Strain Growth Phenomenon

The strain growth phenomenon is an unsolved fundamental problem in the dynamic elastic response of containment vessels subjected to internal blast loading, which may seriously influence the design of multiple-use containment vessels. Because strain growth may cause increased local structural deformation in multiple-use containment vessels, it is important to consider this phenomenon when designing multiple-use containment vessels. In this paper, the mechanisms of strain growth, its influencing factors, and control methods are presented. Based on the understanding of the strain growth phenomenon, the guidelines and procedures for the design of multiple-use containment vessels are proposed. Employing the design guidelines, application examples are presented to demonstrate how to control strain growth in containment vessels. Because the strain growth phenomenon has not been considered in the design method or design code for multiple-use explosion containment vessels, understanding of the strain growth mechanisms and the proposed design guidelines may contribute to the safe design of containment vessels.