Dynamic performance of squeeze-film bearings

Earlier work has shown that oil-film forces can be modelled by linear coefficients. Identification techniques were used to generate numerical values for these coefficients. This paper has shown the invalidity of applying the perturbation techniques normally used in bearing studies to derive expressions for linearized coefficients to represent a cavitated oil-film. An alternative approach was developed based upon energy techniques to obtain estimates for linearized coefficients. Some current work being undertaken suggests that an alternative analytical approach is possible. These results will be reported in due course

Optimization of the Injectors Position for an Electric Arc Furnace by using CFD Simulation

In this study, complex processes in a typical Electric Arc Furnace (EAF) such as combustion, radiation, heat, and mass transfer were solved and the optimum injector location was found using computational fluid dynamics (CFD). The main aim of the injection optimization was to improve the thermal performance and the metallurgical process by changing the injection angle, the central angle of the injector (CAI), and injector length. Fifteen parametric cases were predicted and analyzed for optimization study. To decrease each simulation solution time of each cases, a polyhedral mesh structure was used instead of tetrahedral mesh for the EAF geometry. Thus, the total element number of the model was decreased by 1/5 while providing faster and unchanging results compared to the case with a tetrahedral mesh structure. The response surface optimization method was used for the optimization study. As a result, the optimum injector positioning was obtained as injection angle: -45°, injector length 614 mm, and CAI: 60°

Helping parents to help children overcome fear: the influence of a short video tutorial

Objectives Anxiety runs in families, and its transmission is largely environmental. However, studies rarely explore this process in clinically anxious parents or ask participants to face a genuine fear. We also do not know whether this process is modifiable. This study will explore these questions using a sample of clinically anxious parents. Design Experimental design comparing clinically anxious parents with non‐anxious parents, and exploring the effects of a tutorial intervention versus a control group. Methods Parents with and without anxiety disorders and their children (5–9 years) participated (N = 72). Children chose two fearful animal stimuli. Parents helped the child approach the first in graded steps. The following parental behaviours were recorded: positive/negative verbal information; positive/negative modelling; encouragement/praising of approach/avoidance behaviours. Half the parents were then randomly assigned to a short video tutorial advising how to help children cope with fearful situations. The remainder watched a control video. The approach task was repeated with the second stimulus. Results Parenting behaviours fell into two categories: ‘approach parenting’ (encouraging/praising/modelling approach; positive verbal information) and ‘avoidance parenting’ (encouraging/praising/modelling avoidance; negative verbal information). The parenting tutorial increased ‘approach parenting’ and decreased ‘avoidance parenting’ and was associated with increased child approach towards fearful stimuli. This was not moderated by parent or child anxiety. Conclusions Parenting, particularly ‘avoidance parenting’, is associated with children's approach and avoidance. A short video tutorial modified these parenting behaviours and reduced avoidance. These effects were apparent regardless of parent or child anxiety level

Razvoj i biofarmaceutsko vrednovanje pripravka za povećano oslobađanje tramadol hidroklorida na principu osmotske tehnologije

Extended release formulation of tramadol hydrochloride (TRH) based on osmotic technology was developed and evaluated. Target release profile was selected and different variables were optimized to achieve the same. Formulation variables like level of swellable polymer, plasticizer and the coat thickness of semipermeable membrane (SPM) were found to markedly affect the drug release. TRH release was directly proportional to the levels of plasticizer but inversely proportional to the levels of swellable polymer and coat thickness of SPM. Drug release from developed formulations was independent of pH and agitation intensity but dependent on osmotic pressure of the release media. In vivo study was also performed on six healthy human volunteers and various pharmacokinetic parameters (cmax, tmax, AUC0-24, MRT) and relative bioavailability were calculated. The in vitro and in vivo results were compared with performance of two commercial tablets of TRH. The developed formulation provided more prolonged and controlled TRH release as compared to marketed formulation. In vitro-in vivo correlation (IVIVC) was analyzed according to Wagner-Nelson method. The optimized formulation (batch IVB) exhibited good IVIV correlation (R = 0.9750). The manufacturing procedure was found to be reproducible and formulations were stable during 6 months of accelerated stability testing.U radu je opisana priprava i evaluacija pripravaka tramadol hidroklorida (TRH) na principu osmotske tehnologije. Da bi se postigao željeni profil oslobađanja mijenjane su različite varijable. Pokazalo se da najveći utjacaj na oslobađanje ljekovite tvari imaju udjeli polimera koji bubri, plastifikatora i debljina ovojnice polupropusne membrane (SPM). TRH oslobađanje bilo je proporcionalno udjelu plastifikatora, a obrnuto proporcionalno udjelu polimera i vrijednosti SPM. Oslobađanje ljekovite tvari bilo je neovisno o pH i intenzitetu miješanja, a ovisno o osmotskom talku medija. U in vivo studiji provedenoj na šest zdravih volontera određeni su farmakokinetički parametri (cmax, tmax, AUC0-24, MRT) i izračunata relativna bioraspoloživost. Rezultati dobiveni u pokusima in vitro i in vivo uspoređeni su s dvije vrste komercijalno dostupnih tableta TRH: oslobađanje ljekovite tvari iz pripravka razvijenog u ovom radu bilo je dulje i više kontrolirano. In vitro-in vivo korelacija (IVIVC) je analizirana prema Wagner-Nelsonovoj metodi. Optimizirani pripravak (IVB) pokazao je dobru IVIV korelaciju (R = 0,9750). Proizvodni proces je bio reproducibilan i pripravci su bili stabilni tijekom 6 mjeseci u uvjetima ubrzanog starenja

Activating mutations of STAT5B and STAT3 in lymphomas derived from gamma delta-T or NK cells

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