MIXING/SEGREGATION POTENTIAL IN BINARY LIQUID FLUIDIZED BEDS

The mechanism underlying mixing/segregation of binary particles in liquid fluidized beds is reviewed and investigated in this paper. Binary mixtures of particles, when fluidized, sometimes segregate and display a behaviour called layer inversion, At low fluid velocities, one of the components is primarily found in a discrete layer at the bottom of the bed, while the other is predominantly at the top. At higher fluid velocities, the order of arrangement is reversed. The literature provides a variety of explanations for this phenomenon, derived from quite different theoretical bases. A comparative analysis of these different approaches is presented here together with the experimental results available in the literature. Based on the best model, further experimental investigation is carried out to provide; (i) comprehensive criteria to predict whether a given binary mixture of any type (both size and density variant, size variant only, density variant only) will mix/segregate or show layer inversion, and (ii) mixing/segregation regime map in terms of size ratio and density ratio of the particles for a given fluidizing medium. Therefore, knowing the properties of given particles, a second type of particles can be chosen in order to avoid or to promote segregation according to the particular process requirement.     

Relationship between functional status and the capacity to regulate behavior among elderly persons following hip fracture.

Objective: To assess the relationship between behavioral self-regulation and functional status among older rehabilitation inpatients. Study Design: Prospective outcome study. Setting: Fourteen inpatient rehabilitation units and skilled nursing facilities. Participants: Two hundred twelve older adults following hip fracture or replacement. Measures: Mini Mental State Exam (MMSE), Geriatric Depression Scale, Behavioral Dyscontrol Scale (BDS), and nurse-rated functioning on activities of daily living (ADLs) and the Barthel Index. Results: Risk-adjusted analyses found the BDS to be strongly associated with all 11 ADLs and the Barthel Index. The MMSE made an additional contribution to 4 models. Conclusion: The results suggest that the ability to use intentions to guide purposeful behavior is an important contributor to functioning among older adults, affecting rehabilitation potential. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of the concentration-dependent surface diffusion model on the multicomponent fixed-bed adsorption systems

The ability of bone char to adsorb three metal ions, namely, cadmium, copper and zinc, from effluents in fixed beds has been studied. Two binary metal ion sorption systems, Cd+Cu and Cu+Zn, have been investigated. The variables studied include metal ion solution flowrate, initial metal ion concentration, and bone char particle size bed height. The experimental breakthrough curves for each binary system were measured at five bed heights.A multicomponent film-surface diffusion model has been developed to predict the breakthrough curves by incorporating the IAS for both the Langmuir and the Sips equations, since they both correlate the single component equilibrium isotherm data well. A novel development is the modification of the solution methodology, previously restricted to a constant diffusivity, to incorporate a variable diffusivity correlated with adsorbent coverage by the constant self-diffusivity. The self-diffusivities for the metal ions have been evaluated.     

Effect of pulsing on reaction outcome in a gas–liquid catalytic packed-bed reactor

A novel experiment is described for studying the effect of flow regime on reaction outcome for a consecutive-parallel reaction. By taking advantage of the convective nature of disturbances that grow into pulses in gas–liquid packed-bed reactors, it is shown that it is possible to compare reaction behavior for pulsing and trickling at the same flow rates. This contrasts previous studies where effects of regime were found, but at different flow rates. This experiment is accomplished by packing the column with mostly inert particles and confining the catalytically active region either near the inlet, where pulses have not yet formed, or near the end where they have developed. It is found that for the reaction of phenylacetylene to styrene and ethylbenzene over a platinum/alumina catalyst, where pulses are present in the bottom of the reactor but not at the top, about a 15% increase in styrene concentration, as an intermediate, occurs under pulsing conditions.     

U.v. irradiation-induced crosslinking of solid poly(ethylene oxide) modified with tetraalkyl ammonium salt

Crosslinked poly(ethylene oxide) (PEO) modified with a quaternary tetraalkyl ammonium salt, ethyl methacrylate dimethyldodecylammonium bromide, was prepared by exposure of the solid blend to ultraviolet radiation from a high-pressure 150 W mercury lamp. The photochemical crosslinking of the blends proceeded in the presence of benzophenone as a hydrogen-abstracting agent. Gel fraction yield exceeded 85%, equilibrium swelling in water varied from 3.0 to 5.0, and the equilibrium swelling in chloroform from 6.5 to 12.5. The networks obtained have been characterized by elemental analysis, i.r.,¹H n.m.r., and d.s.c. measurements and their microstructure, water absorption and equilibrium swelling have been discussed.     

HEAT TRANSFER IN THREE-PHASE FLUIDIZED BEDS WITH NON-NEWTONIAN PSEUDOPLASTIC SOLUTIONS

Heat transfer experiments have been conducted in three-phase fluidized beds (TPFB) of 3 and 5 mm glass spheres. To assess the effect of non-Newtonian flow behavior, concentrated pseudoplastic xanthan solutions were employed. The gas and liquid superficial velocities range from 0.81 to 14.4 cm/s and 1.27 to 9.0 cm/s respectively. The impact of these parameters as well as the effect of the effective liquid viscosity, and the solid size on heat transfer in TPFB are discussed. All heat transfer coefficients can be discribed satisfactorily by a new correlation which predicts the Nu-values in TPFB with pseudoplastic solutions with ±9.13% average standard deviation.     

护士职业性体力活动与工作疲溃感关系的研究

目的探讨护士职业性体力活动与工作疲溃感的相关性,为及时进行健康干预提供指导,为重症监护病房（ICU）合理的人员配置提供参考。方法连续性纳入综合ICU 2008年10月至2009年10月收治的符合纳入标准的病人125例（入院急诊手术病人42例占33.6%,择期手术病人12例占9.6%,重症非手术病人28例占22.4%,急诊重症非手术病人43例占34.4%）,采用重症监护护理评分系统测量31名护理人员（5个护理小组）的护理工作量,利用工作疲溃感量表分别测量小组制护理中5组护理人员压力反应,分析不同护理工作量对护理人员压力的影响。结果不同入科类型病人平均日护理工作量评分差异有统计学意义（F=40.53,P=0.00）;各护理小组平均日护理工作量评分差异有统计学意义（F=15.84,P=0.00）;各护理小组情绪疲溃感同护理工作量均成显著性正相关（r=0.963,P=0.002;r=0.949,P=0.004;r=0.970,P=0.000;r=0.911,P=0.011;r=0.886,P=0.019）,工作冷漠感同护理工作量无相关性（r=0.109,P=0.837;r=0.358,P=0.485;r=0.575,P=0.177;r=-0.253,P=0.809;r=-0.790,P=0.062）,部分组工作无成就感同护理工作量呈显著性正相关（r=0.624,P=0.168;r=0.953,P=0.003;r=0.810,P=0.027;r=0.803,P=0.054;r=0.145,P=0.785）。结论护士职业性体力活动与情绪疲溃感显著相关,与工作冷漠感、工作成就感相关性不显著。     

健康教育在治疗阻塞性睡眠呼吸暂停低通气综合征中的价值

目的探讨健康教育在治疗阻塞性睡眠呼吸暂停低通气综合征（OSAHS）中的价值。方法 150例OS-AHS患者按随机数字表法分成观察组和对照组,每组75例。观察组实施健康教育,对照组75例未实施健康教育,其他治疗及护理2组均相同。结果观察组治愈率高于对照组（96.0%vs 66.7%）,并发症发生率低于对照组（12.00%vs 37.33%）,2组比较差异均有统计学意义（均P〈0.05）。结论健康教育可以提高OSAHS患者治愈率和生存质量、降低并发症发生率,实现防治的最佳目标和价值。     

Hydrodynamic characteristics of gas–solid fluidization at high temperature

Effect of temperature on the hydrodynamics of bubbling gas–solid fluidized beds was investigated in this work. Experiments were carried out at different temperatures ranged of 25–600°C and different superficial gas velocities in the range of 0.17–0.78 m/s with sand particles. The time‐position trajectory of particles was obtained by the radioactive particle tracking technique at elevated temperature. These data were used for determination of some hydrodynamic parameters (mean velocity of upward and downward‐moving particles, jump frequency, cycle frequency, and axial/radial diffusivities) which are representative to solids mixing through the bed. It was shown that solids mixing and diffusivity of particles increases by increasing temperature up to around 300°C. However, these parameters decrease by further increasing the temperature to higher than 300°C. This could be attributed to the properties of bubble and emulsion phases. Results of this study indicated that the bubbles grow up to a maximum diameter by increasing the temperature up to 300°C, after which the bubbles become smaller. The results showed that due to the wall effect, there is no significant change in the mean velocity of downward‐moving clusters. In order to explain these trends, surface tension of emulsion between the rising bubble and the emulsion phase was introduced and evaluated in the bubbling fluidized bed. The results showed that surface tension between bubble and emulsion is increased by increasing temperature up to 300°C, however, after that it acts in oppositely.     

垂体腺瘤卒中的治疗及护理

目的：探讨了垂体腺瘤卒中的治疗及护理。方法：回顾分析36例垂体腺瘤卒中的临床表现以及手术治疗情况。结果：经蝶手术33例,经额手术3例。全切除26例,次全切除5例,部分切除5例。术后头痛缓解,呕吐停止,有意识障碍者逐渐清醒,术前视力在有光感以上者均有不同程度好转,眼肌麻痹均有改善。随访28例,治愈7例,缓解16例,无缓解2例,复发3例。结论：垂体腺瘤卒中尽早经蝶手术减压,术后严密监测病情变化及生命体征,有效护理对于改善预后意义重大。