The present study was motivated by problems at continuous casting plants where a variety of thermally induced defects were observed. The paper outlines an experimental method for the measurement of cooling intensity in the secondary cooling area where nozzles are applied. The precision of a variety of experimental methods is discussed. The nozzles have been investigated in terms of pressure setting, the influence of casting speed, and behaviour in the overlapping areas. The tests have provided information on heat transfer coefficient characteristics and heat flux distribution on the cooled steel surface. The paper presents new experimental findings regarding specification of the Leidenfrost temperature, which is the point between high and low surface temperature regions where a large difference in cooling intensity is observed. The paper also deals with the problems of homogeneity of cooling along the nozzle spray angle and in the overlapping area where thermal 'stripes' occur. The sensitivity of this problem to the pressure of the coolant is discussed.

One‐step preparation of composites of alkaline poly(6‐hexanelactam) (PCL) with solid lubricants (SL), such as graphite and molybdenum disulfide, is an energy‐saving process as additional polymer fusion and melt mixing are not necessary. The initiator/activator system used were: (i) sodium dihydrido‐bis(2‐methoxyethoxo) aluminate (SYN)/cyclic trimer of phenyl isocyanate (PIC); (ii) sodium/hexamethylene‐1,6‐diisocyanate (HMDIC); (iii) SYN/HMDIC. These systems have been found suitable for the composite synthesis since they are relatively insensitive to traces of humidity and other low‐molar‐mass compounds which may be adsorbed on lubricant surfaces. Incorporated graphite (up to 20 wt.‐%) and MoS2 (up to 40 wt.‐%) do not perceptibly affect glass transition temperature, melting temperature and crystallization temperature while polymer yield, polymerization degree and rate decrease. The crystallinity assessed by DSC passes through a maximum at 20% of MoS2 in contrast to that detected by X‐ray diffraction (XR) measurements. As expected, the mean spherulite diameter drops profoundly. Both SL affect mechanical properties of produced composites: (i) increase the modulus; (ii) decrease the compliance, the time dependence of which remains close to that observed for the matrix; (iii) reduce the yield strength; (iv) slightly lower the impact strength of composites. A tentative hybrid composite containing 15 wt.‐% of graphite, 5 wt.‐% of MoS2, and 5 wt.‐% of mineral oil (as a liquid lubricant) shows a modulus high enough and its propensity to creep is not enhanced. The observed changes in mechanical properties of PCL caused by the incorporation of SL do not preclude applications analogous to those of unfilled PCL. Friction properties of the composites were beyond the scope of this work.

Inverse problems deal with determining the causes on the basis of knowing their effects. The object of the inverse parameter estimation problem is to fix the thermal material parameters (the cause) on the strength of a given observation of the temperature history at one or more interior points (the effect). This paper demonstrates two novel approaches to the inverse problems. These approaches use two artificial intelligence mechanisms: neural network and genetic algorithm. Examples shown in this paper give a comparison of results obtained by both of these methods. The numerical technique of neural networks evolved from the effort to model the function of the human brain and the genetic algorithms model the evolutional process of nature. Both of the presented approaches can lead to a solution without having problems with the stability of the inverse task. Both methods are suitable for parallel processing and are advantageous for a multiprocessor computer architecture.

Polycaprolactam containing glass fillers was prepared by activated anionic adiabatic polymerization. The fillers and coupling agents used reduce the polymerization rate, crystalline fraction and size of supermolecular structures. The reported procedure is suitable for a one-stage preparation of bulky objects from composite materials. Mit kurzen Glasfasern und Mikrokugeln gefiilltes Polycaprolactam. I . Herstellung von Verbundstoffen durch anioniseh aktivierte adiabatische PolymerisationMit Glas gefiilltes Polycaprolactam wurde mittels aktivierter anionischer adiabatischer Polymerisation hergestellt. Die verwendeten Fullstoffe und Haftvermittler verringern die Polymerisationsgeschwindigkeit, den kristallinen Anteil und die GroSe der ubermolekularen Strukturen. Das beschriebene Verfahren eignet sich zur Herstellung von massiven Objekten aus Verbundstoffen nach einem Einstufenverfahren. Actr Polymerica 36 (1985) Nr. 4 221 HORSKP and I~o L A~~K : Polycaprolactam filled with short glass fibres and microbeads. I lIosuxanpodaammaw, nanoanennbzii xopomxuu cmexs.wnbwu eoJzoxnmu u auxpoc@epawu. I . Hazomosfienue xownoauyuonnbcx aamepucutoe nymefi anuonnoii aEmueupoeannoii a&a6amuuecxoii nofiuaepuaayuu a a~a b a~~=~e c~o i n o n a~e p a 3 a q~n . H C~O J I~~O B~H H~I~ Hartommemi II annpeTn noHHmamT cKopocTb n o n~~e p m a q~~, IIOJlIIKanpOJIaKTaM, COAepma~Ha CTeKJIRHHbIe HallOJIHHTeJIH, BHJI IlOJIyWH IIyTeM aKTHBAPOBaHHOfi aHHOHHOfi OIIIICaHHbIfi B CTaTbe MeTOn IIpI1rOAeH gMf3HbluaIoT KPHCTaXJIII9HOCTb II pa8MepbI HaAMOneKyJIRpHbIX CTPYKTYP. &TlR OnHOCTaffIIZiHOrO IIOJIYWHESR Ei3neJII1Zi 60~1bmoro 06.beMa I13 KOMII03HqHOHHOFO MaTepHaJIa. H O R S K~ ant1 I~O L A~~K : Pol>-caprolactam filled with short glass fibres and microbeads. I Diameter of W,2) spherulites P m Acta Polymerica 36 (1985) Nr. 4