Physical and mathematical modelling of ladle metallurgy operations

Experimental measurements are reported, on the velocity fields and turbulence parameters on a water model of an argon stirred ladle. These velocity measurements are complemented by direct heat transfer measurements, obtained by studying the rate at which ice rods immersed into the system melt, at various locations. The theoretical work undertaken involved the use of the turbulence Navier-Stokes equations in conjunction with the kappa-epsilon model to predict the local velocity fields and the maps of the turbulence parameters. Theoretical predictions were in reasonably good agreement with the experimentally measured velocity fields; the agreement between the predicted and the measured turbulence parameters was less perfect, but still satisfactory. The implications of these findings to the modelling of ladle metallurgical operations are discussed

The turbulent recirculating flow field in a coreless induction furnace. A comparison of theoretical predictions with measurements

A mathematical representation for the electromagnetic force field and the fluid flow field in a coreless induction furnace is presented. The fluid flow field was represented by writing the axisymmetric turbulent Navier-Stokes equation, containing the electromagnetic body force term. The electromagnetic body force field was calculated by using a technique of mutual inductances. The kappa-epsilon model was employed for evaluating the turbulent viscosity and the resultant differential equations were solved numerically. Theoretically predicted velocity fields are in reasonably good agreement with the experimental measurements reported by Hunt and Moore; furthermore, the agreement regarding the turbulent intensities are essentially quantitative. These results indicate that the kappa-epsilon model provides a good engineering representation of the turbulent recirculating flows occurring in induction furnaces. At this stage it is not clear whether the discrepancies between measurements and the predictions, which were not very great in any case, are attributable either to the model or to the measurement techniques employed

The electromagnetic force field, fluid flow field and temperature profiles in levitated metal droplets

A mathematical representation was developed for the electromagnetic force field, the flow field, the temperature field (and for transport controlled kinetics), in a levitation melted metal droplet. The technique of mutual inductances was employed for the calculation of the electromagnetic force field, while the turbulent Navier - Stokes equations and the turbulent convective transport equations were used to represent the fluid flow field, the temperature field and the concentration field. The governing differential equations, written in spherical coordinates, were solved numerically. The computed results were in good agreement with measurements, regarding the lifting force, and the average temperature of the specimen and carburization rates, which were transport controlled

Carbon-oxygen equilibrium and homogeneous nucleation of carbon monoxide bubbles in levitated molten iron

Imperial Users onl

Smart Fridge / Dumb Grid? Demand Dispatch for the Power Grid of 2020

In discussions at the 2015 HICSS meeting, it was argued that loads can provide most of the ancillary services required today and in the future. Through load-level and grid-level control design, high-quality ancillary service for the grid is obtained without impacting quality of service delivered to the consumer. This approach to grid regulation is called demand dispatch: loads are providing service continuously and automatically, without consumer interference. In this paper we ask, what intelligence is required at the grid-level? In particular, does the grid-operator require more than one-way communication to the loads? Our main conclusion: risk is not great in lower frequency ranges, e.g., PJM's RegA or BPA's balancing reserves. In particular, ancillary services from refrigerators and pool-pumps can be obtained successfully with only one-way communication. This requires intelligence at the loads, and much less intelligence at the grid level

Antibody response to hepatitis b immunization in Egyptian children with sickle cell disease

Background: Despite improvement in the safety of blood products, sickle cell disease (SCD) and thalassemic patients are at greater risk than the general population for hepatitis B infection and chronic liver disease, making hepatitis B immunization especially important for this population. This study was conducted to evaluate and follow up the antibody response to hepatitis B vaccination, in patients with SCD, after 1-15 years of vaccination. Methods: participants were 30 SCD and 30 thalassemic patients attending the Hematology Department, Children’s Hospital, Cairo University as well as 30 ages and sex matched normal controls. They were subjected to clinical evaluation, complete blood count, and measurement of liver transaminases, serum bilirubin, and serum ferritin levels as well as estimation of anti-HBs titer by enzymatic immunoassay. Results: Anti-HBs titers in SCD patients ranged between 5.6 and 381 IU/L (54.83 ± 15.30), while the levels of thalassemic patients ranged between 16 and 343 IU/L (93.4 ± 30) and those of the control group ranged from 10 to 523 IU/L (83.4 ± 28.1) which revealed statistically significant decrease in SCD patients compared to thalassemic and healthy controls (p =0.0317). Out of the 30 SCD patients, 40% showed anti-HBs titer below 10 IU/L (non-protective titer), while none of the thalassemic patients or the control group revealed the same. Achievement of a protective titer had no correlation with sex, consanguinity, or any of the clinical or laboratory data tested. Conclusion: Immune dysfunction in thalassemia is not playing a major role in response to hepatitis B vaccination. However, SCD children should have their anti-HBs titer measured after routine hepatitis B immunization to ensure that they achieved protective titer, then after 1 year of vaccination and repeated every 5 years and those who do not seroconvert should receive additional doses. Booster HBV vaccination of unprotected SCD patients seems mandatory.Keywords: sickle cell, immunity, hepatitis B, immunizationEgypt J Pediatr Allergy Immunol 2010;8(2):67-7

The tutktuks in Maadi: What is their presence disrupting?

Why is the maneuvering of the tuktuks in certain elite spaces in Maadi a disruption to the fragile and in many ways, imaginary boundaries between people, spaces, objects, histories and narratives? How can one street, whether it is the one where I live or Street 9 where I did my fieldwork, encompass a wide range of lives and worlds that do not touch ? Why is it ok for the tuktuk to be seen in Arab El Maadi, usually conceived as a lower-class neighborhood adjacent to Sarayat El- Maadi, but when it moves in Sarayat El-Sarayat, it becomes a disruption to the senses? Why is the tuktuk in motion contested in some areas, and what happens when it stays still in others? How do the elites of Maadi justify the exclusion of the tuktuk from their elite spaces?How deep does the pool of their common sense goes? Is there a history to this pool? If so, how much are the dead still alive and in what ways are they summoned back? In this thesis, I answer these questions through an ethnography of storytelling of the life worlds I encountered. My ethnographic research on the tuktuks in Maadi as well as the peoples steering them is productive in affectively encountering Maadi\u27s social geographies of power. Their disruptive and controversial mobility in elite spaces in Maadi sheds light on how social divides that are not physically constructed as walls, yet are invisible palpable barriers signify the social and historical segregation of Maadi

The fantastic of dignified journey "The dignified journey in Al-tashwof ela rejal altasawof by Ibn Al-Zayyat Al-tdeli an example"

  This research is composed of two parts: The first is theoretical and applicational. The theoretical section clarified both  The fantastic and dignified terms. It elaborates saying in  "The fantastic of dignified journey" described  fantastic especially for representing features of the fantastic. Moreover it adds to what corresponds to the dignity nature. On the other hand  the applicational section analyses texts of the dignified journeies in altasawof. It also reveals several important results of this section like expanding time frequency of the dignified journey, the changeable criterion based in texts in judging texts according to the tribal receiver of dignity. Furthermore, there appeared a lot of topics like "subjects of I", with absence of  "subjects of You" ones. Another thing resulted there the vanishing of literary mission in the condensed dignified journeies through news or a statement. At last, there appeared two new functions for fantastic teaching and cognitive, in addition to the main tasks of the fantastic: literary and the socialistic ones.            

Subjectification of space image in immigration text Cairo of Al Muiz in Al Abdari journey an example

  This research is composed of two parts: The first is theoretical and separates the saying from the subjectification idiom with its considerable presence in criticism surrounding the immigration space. It also explains the marks and impressions which make difference between it and the factual and artistic space. The second one is applicable. It takes to pieces the image of Cairo Al Muiz in the journey of Al Abdari, considered as subjectified image and also observes its subjectification move and the effective elements in it. Its most significant result is that the immigration space has its own distinguished character as a subjectified space that lies in moderate position between the factual and artistic space, and expresses the age of  journey, its culture, situations, emotions and also effect of space and period in it. Cairo in Al Abdari text which has lost both its historical sacred distance and has changed into a dismissing frightening space that it explained Al Abdari age, its believing ideal and national enthusiasm, its desolation and estrangement of the civilian form and its intimate tie to the space of the ego=mother space=his village Haha