Numerical investigation of the temperatures and thermal stresses in thermal treatment of metallic articles

An algorithm is proposed for the numerical computation of the temperatures, stresses, and strains in articles during heat treatment. Specific computations are performed for plates from ShKh15 steel.     

High-speed spinning and orientational strengthening of polyester fibres. Analysis and prospects for development. A review

The processes are classified and the theoretical and technological premises for substantiation of orientational strengthening schemes are examined. Modern technological schemes for separate and combined processes of high-speed spinning and orientational strengthening are described, and the prospects for development of new technologies are evaluated. The evolution of orientational strengthening technology is based on multistage drawing for obtaining high-strength fibres and one-stage processes for obtaining medium-strength fibres. Examples of the implementation of modern schemes for production of polyester fibres are reported. Translated from Khimicheskie Volokna, No. 6, pp. 7–13. November–December, 1997.     

Heat transfer in a “pseudoturbulent” bed of dispersed material

A two-phase model is proposed for the steady heat exchange between a surface and a pseudoturbulent bed of dispersed material. Expressions are obtained for the temperature fields of the gaseous and solid phases.Notation _g effective thermal conductivity of gaseous phase - _s effective thermal conductivity of the mixed solid phase - porosity - _m molecular thermal conductivity - d particle diameter - temperature of dispersed bed at a large distance from heat source - , g gas temperature - _p particle temperature - _w wall temperature - x current coordinate in the direction perpendicular to the wall - l bed thickness - q heat flux - coefficient of heat exchange between wall and pseudoturbulent bed of dispersed material - ^* coefficient of interphase heat exchange - _g=_g/_w dimensionless gas temperature - _p = _p/_w dimensionless particle temperature - Y = x/d dimensionless coordinate - L =l/d dimensionless bed thickness - A_h dimensionless coefficient of interphase heat exchange - Nu_g = d/_s Nusselt number Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 3, pp. 465–469, September, 1981.     

Join-Idle-Queue: A novel load balancing algorithm for dynamically scalable web services

The prevalence of dynamic-content web services, exemplified by search and online social networking, has motivated an increasingly wide web-facing front end. Horizontal scaling in the Cloud is favored for its elasticity, and distributed design of load balancers is highly desirable. Existing algorithms with a centralized design, such as Join-the-Shortest-Queue (JSQ), incur high communication overhead for distributed dispatchers.We propose a novel class of algorithms called Join-Idle-Queue (JIQ) for distributed load balancing in large systems. Unlike algorithms such as Power-of-Two, the JIQ algorithm incurs no communication overhead between the dispatchers and processors at job arrivals. We analyze the JIQ algorithm in the large system limit and find that it effectively results in a reduced system load, which produces 30-fold reduction in queueing overhead compared to Power-of-Two at medium to high load. An extension of the basic JIQ algorithm deals with very high loads using only local information of server load.     

Differences in the stimulation of NO synthesis during heat shock in genetically different rats]

OBJECTIVES: In certain younger patients with congestive heart failure (CHF), Doppler/echocardiography has identified a "restrictive" pattern of early diastolic ventricular filling characterized by very rapid early filling and a steep deceleration slope. We asked whether a similar restrictive pattern can be identified in very old patients with CHF, and if so, what are its clinical correlates and prognostic implications. DESIGN: Retrospective cohort with prospective follow-up. SETTING: Academic long-term care facility. PARTICIPANTS: Thirty-nine residents with clinical CHF (age 89 +/- 5 (SD) years) MEASUREMENTS: Transmitral Doppler flow, clinical characteristics, recurrent CHF episodes, hospitalizations, and mortality were measured. RESULTS: Fifteen (38%) of the subjects had restrictive filling patterns, characterized by a ratio of early to late flow (E/A) > 1.00 and 24 (62%) had nonrestrictive patterns. The restrictive pattern was associated with a longer duration of CHF, more angina, and higher rate of symptomatic recurrences of CHF. CONCLUSION: A restrictive diastolic filling pattern may represent a late stage in the evolution of congestive heart failure when left ventricular filling pressure is markedly increased. The treatment of CHF in older patients may need to account for different patterns of diastolic filling.     

Sound Modes of Superfluid 3He in Aerogel

We present the results of experiments on sound propagation at audio frequencies in ³ He-filled aerogel. Sound modes were observed at temperatures of 0.8–100 mK in an aerogel sample of 98% porosity. We find that below T _c for superfluid ³ He in the aerogel matrix the speed of sound in the composite system increases by as much as 1.5%. Also below the aerogel T _c new modes appear which correspond to propagation speeds of up to 10 m/s.     

Interaction of mass exchange and jet tension in spinning of nitron fibres

The reciprocal effect of mass exchange and tension of spun Nitron fibre in the spinning bath was demonstrated. The concentration region of the concentration of solvent in the spinning bath which guarantees attaining high elasticity and a strength of 100 cN/tex and the more finished fibre with a linear density of 0.01 tex was established.Nitron Plant, Novoiazot Industrial Association, Uzbekistan; Mogilev Institute of Technology, Belarus'. Translated from Khimicheskie Volokna, No. 6, pp. 41–43, November–December, 1993.     

POSSIBILITIES OF TERRA COTTA CASTING

Experimental method.—The casting properties, viscosity, specific gravity and drying behavior of three kaolins, two ball clays, one fire-clay and four representative commercial bodies, together with terra cotta clays, were studied. The clays and bodies were treated with varying amounts of salts and cast in the form of small ashlars. Conclusions.—Kaolins have an open structure but do not develop strength on drying. Bonding properties are furnished by ball clays which, however, tend to seal against the mold. Commercial terra cotta bodies tested do not possess good casting properties but can be modified through a study of the component clays. Mechanical difficulties attending the casting of terra cotta render the feasibility of the process doubtful at the present time.