Numerical and Experimental Investigation of Particle Separation and Flow Behavior Inside an Induction Crucible Furnace

Die Existenz der nichtmetallischen Einschlüsse in der Metallschmelze führt zur Verschlechterung der physikalischen Eigenschaften des gegossenen Stahls. Die im Rahmen des SFB 920 entstandene Arbeit beschäftigt sich hauptsächlich mit der Untersuchung der reaktiven Reinigung und aktiven Filtration der Metallschmelze im Induktionsofen mithilfe der numerischen Strömungsmechanik. Dazu werden im Rahmen der Arbeit neue numerische Simulationsmodelle entwickelt. Die Ergebnisse zeigen, dass die reaktive Reinigung einen ausschlaggebenden positiven Einfluss auf die Entfernung der Einschlüsse aus der Metallschmelze hat, wobei der Reinheitsgrad der Metallschmelze innerhalb einer kurzen Eintauchzeit des kohlenstoffgebundenen Filters ansteigt. Der in der reinen aktiven Filtration erzielte Reinheitsgrad ist deutlich niedriger als im Falle der reaktiven Reinigung. Des Weiteren befasst sich die Arbeit mit dem Effekt der Turbulenzmodellierung auf die Beschreibung der Schmelzeströmung und der Verteilung der Einschlüsse. Weiterhin stellt die Arbeit ein experimentelles Wassermodell zur Nachbildung der rezirkulierenden Schmelzeströmung im Induktionsofen vor.:Abstract List of figures List of Tables Nomenclature 1 Introduction 2 State of the Art 3 Numerical Model 4 Results 5 Summary and Conclusion 6 Outlook BibliographyDuring the continuous casting, non-metallic inclusions such as deoxidation or reoxidation products may arise in steel melt due to different reactions. These inclusions have to be removed from the melt with the aim of improving the cleanliness of steel products. There are many approaches in continuous casting to enhance inclusion removal from the melt. However, this Phd thesis focuses particularly on inclusion removal by reactive cleaning and active filtration during the melt casting in an induction crucible furnace using ceramic foam filter developed in CRC 920. For this purpose, a numerical model is developed in OpenFOAM in order to simulate the melt flow and reactive cleaning as well as active filtration. Besides the numerical model, an experimental water model are created to validate the capability of the numerical model to predict the recirculating turbulent flow in the induction crucible furnace. The results show that reactive cleaning and the formation of carbon monoxide bubbles, which arise on the inclusions, have a positive impact on the melt cleanliness. Reactive cleaning can improve inclusion removal and enhance the melt cleanliness sufficiently. Based on the results, one can conclude that the rate of inclusion removal in case of reactive cleaning is considerably higher than that in case of active filtration. Furthermore, the results indicate the considerable influence of filter position and filter number on the flow field as well as on the cleaning efficiency in the induction crucible furnace. Moreover, the results shows that turbulence modeling has a considerable impact on the prediction of the melt flow and inclusion dispersion in the induction crucible furnace.:Abstract List of figures List of Tables Nomenclature 1 Introduction 2 State of the Art 3 Numerical Model 4 Results 5 Summary and Conclusion 6 Outlook Bibliograph

Impact of Country-of-Origin on Product Purchase Decision.

The purpose of this study is to explain, explore and to analyse the possible impact of the different Country-of-Origin on consumers purchase decision on three different categories of products. This study is conducted from a consumer-based view to investigate what to what extend Country-of-Origin effect the customers purchasing decision for three different categories of products? The study also investigated the possible behaviour of different customers regarding different Country-of-Origin depending upon the different demographic variables different choices and preferences of different customers segments were explored. Different age, gender, education and different income subgroups will be examined and the relevant importance of "Made in Pakistan" cue was analysed with other countries products. Study also analyses the impact of Product Involvement on product purchase decision an relationship of Product Knowledge and product purchase decision is also study. Primary data was collected using standardized questioners from four different cities of Pakistan. Results demonstrated that the people who looks for Country-of-origin information, they have certain images of different countries in different product categories. Research also concluded that Pakistan is only preferred country in Fabric products and not in electronics and cosmetics products.  Product Involvement and Product knowledge does affect the customer choices in term of selecting the countries across different product categories. Demographic variables also influenced the Country-of-Origin effect. “Made in Pakistan” was evaluated better for Fabrics but not for Electronics or Cosmetics. Keywords: Country-of-origin, Product Involvement and Product knowledge, Demographic Variables, Pakistan

Experience with Ventriculoatrial Shunt

Cerebrospinal fluid (CSF) diversion through shunting, either internal or external, is the standard of care for hydrocephalic patients. Although Ventriculoperitoneal (VP) shunt is always the first choice, right atrium for Ventriculoatrial (VA) shunt is considered a suitable and convenient option for drainage of excess CSF in patients with history of abdominal surgeries, peritoneal infection or shunt obstruction.1 Here we are reporting our experience with a patient who underwent VA shunt insertion because of a previous malfunctioning VP shunt. A thorough review of the literature revealed that, although reported worldwide, there is an apparent deficiency of similar reports from Arabian Gulf region. Through this case report, we aim to shed light on this internal CSF diversion method, which could be considered in centers lacking advanced care facilities for procedures like Endoscopic 3rd Ventriculostomy (ETV)

Overhead Based Cluster Scheduling of Mixed Criticality Systems on Multicore Platform

The cluster-based technique is gaining focus for scheduling tasks of mixed-criticality (MC) real-time multicore systems. In this technique, the cores of the MC system are distributed in groups known as clusters. When all cores are distributed in clusters, the tasks are partitioned into clusters, which are scheduled on the cores within each cluster using a global approach. In this study, a cluster-based technique is adopted for scheduling tasks of real-time mixed-criticality systems (MCS). The Decreasing Criticality Decreasing Utilization with the worst-fit (DCDU-WF) technique is used for partitioning of tasks to clusters, whereas a novel mixed-criticality cluster-based boundary fair (MC-Bfair) scheduling approach is used for scheduling tasks on cores within clusters. The MC-Bfair scheduling algorithm reduces the number context switches and migration of tasks, which minimizes the overhead of mixed-criticality tasks. The migration and context switch overhead time is added at the time of each migration and context switch respectively for a task. In low critical mode, the low mode context switch and migration overhead time is added to task execution time, while the high mode overhead time of migration and context switch is added to the execution time of a task in high critical mode. The results obtained from experiments show the better schedulablity performance of proposed cluster-based technique as compared to cluster-based fixed priority (CB-FP), MC-EKG-VD-1, global and partitioned scheduling techniques e.g., for target utilization U=0.6, the proposed technique schedule 66.7% task sets while MC-EKG-VD-1, CB-FP, partitioned and global techniques schedule 50%, 33.3%, 16.7% and 0% task sets respectively

THE ROLE OF INTRAOPERATIVE FROZEN SECTION OF SENTINEL LYMPH NODES IN UPFRONT BREAST CONSERVATION CANCER SURGERY

Objective: Sentinel lymph node biopsy is the standard of care in clinically negative axilla in breast cancer patients for which frozen section (FS) is routinely performed intraoperatively. The objective of this study was to justify the use of FS in terms of number of tests performed and their impact on decision-making and cost saving. Materials and Methods: We retrospectively reviewed our prospectively maintained data from January 2014 to January 2018 for intraoperative FS in upfront breast conservation surgery patients. Results: A total of 357 patients were studied. All were female. Median age was 50 years (24–84). Mean tumour size was 29.11 mm. Numbers of sentinel lymph nodes identified were 1 in 50 (14.2%) patients, 2 in 121 (33.89%) patients and ≥3 in 186 (52%) patients. Number of positive sentinel lymph nodes was 0 in 264 (73.9%) patients, 1 in 62 (17.4%) patients, 2 in 20 (5.6%) patients and ≥3 in 11 (3.08%) patients. Axillary lymph node dissection (ALND) was offered to 30 (8.4%) patients as per the American College of Surgeons Oncology Group Z0011. The results for ALND showed that only 8 (2.3%) out of 30 patients had positive nodes identified in the additional axillary nodes dissected. Sensitivity of FS was 97% and specificity was 98.86%. False-negative rate was 3.22%. Conclusion: Intraoperative FS can be safely omitted in early breast cancer patients undergoing upfront breast conservation cancer surgery due to high sensitivity and specificity leading to low false-negative rates. ALND can be performed as a second operation as warranted only in a minority of patients. Key words: American College of Surgeons Oncology Group Z0011 trial, axillary lymph node dissection, intraoperative frozen section, sentinel lymph node biops

Sensitivity analysis of effective thermal conductivity of open-cell ceramic foams using a simplified model based on detailed structure

The Effective Thermal Conductivity (ETC) of open-cell porous foams can be predicted from the detailed numerical simulation, considering the complex foam structure obtained from three-dimensional (3D) Computed Tomography (CT)-scan images. An alternative approach could be to consider simplified models for a quick and accurate estimation of the ETC. A model for ETC of open-cell porous foams, using such a simplified approach, has been proposed recently which relies upon a single numerical prediction of the dimensionless ETC under vacuum condition, evaluated using the detailed foam structure obtained from 3D CT-scan information. This model is applied in the present study in order to analyze the influence of different parameters, namely the microscopic porosity within the bulk solid material and the direction of heat transfer, on the ETC of open-cell ceramic foams. The present investigation demonstrates that the considered simplified modeling approach offers reasonable accuracy with reduced computational effort for the sensitivity analysis of ETC to different parameters

Channel Clustering and QoS Level Identification Scheme for Multi-Channel Cognitive Radio Networks

The increasing popularity of wireless services and devices necessitates high bandwidth requirements; however, spectrum resources are not only limited but also heavily underutilized. Multiple license channels that support the same levels of QoS are desirable to resolve the problems posed by the scarcity and inefficient use of spectrum resources in multi-channel cognitive radio networks (MCRNs). One reason is that multimedia services and applications have distinct, stringent QoS requirements. However, due to a lack of coordination between primary and secondary users, identifying the QoS levels supported over available licensed channels has proven to be problematic and has yet to be attempted. This article presents a novel Bayesian non-parametric channel clustering scheme, which identifies the QoS levels supported over available license channels. The proposed scheme employs the infinite Gaussian mixture model and collapsed Gibbs sampler to identify the QoS levels from the feature space of the bit rate, packet delivery ratio, and packet delay variation of licensed channels. Moreover, the real measurements of wireless data traces and comparisons with baseline clustering schemes are used to evaluate the performance of the proposed scheme

Tri-Allelic Autosomal STR Patterns Observed in Pakistani Population during Forensic Case Work

The tri-allelic pattern is a genotyping abnormality that can be observed during routine short tandem repeat (STR) profiling in the field of forensic science. Fourteen tri-allelic patterns have been observed in nine different loci during routine forensic casework consisting of 20,000 STR profiles. All these 20,000 STR unrelated profiles were profiled using AmpFlSTR Identifiler Plus® and Global Filer® kits. Tri-allelic patterns can be divided into two types based on RFUs (relative fluorescent units) in peaks of three component alleles. Unequal RFUs of all three peaks are observed in the Type-I pattern, whereas in the Type-II pattern, RFUs of all three peaks are nearly equal. A total of nine novel tri-allelic genotypes were observed out of 20,000 unrelated individuals in the Pakistani population. All of these forensic cases belonged to the Type-I pattern which means that the sum of the height of two smaller peaks is nearly equal to the height of the third larger peak. The frequency of occurrence for all these patterns was compared with already reported data. In this study, eight novel tri-allelic patterns have been reported which are not listed in the National Institute of Standards and Technology (NIST) database as well as in any published article

Progressing towards sustainable machining of steels : a detailed review

Machining operations are very common for the production of auto parts, i.e., connecting rods, crankshafts, etc. In machining, the use of cutting oil is very necessary, but it leads to higher machining costs and environmental problems. About 17% of the cost of any product is associated with cutting fluid, and about 80% of skin diseases are due to mist and fumes generated by cutting oils. Environmental legislation and operators’ safety demand the minimal use of cutting fluid and proper disposal of used cutting oil. The disposal cost is huge, about two times higher than the machining cost. To improve occupational health and safety and the reduction of product costs, companies are moving towards sustainable manufacturing. Therefore, this review article emphasizes the sustainable machining aspects of steel by employing techniques that require the minimal use of cutting oils, i.e., minimum quantity lubrication, and other efficient techniques like cryogenic cooling, dry cutting, solid lubricants, air/vapor/gas cooling, and cryogenic treatment. Cryogenic treatment on tools and the use of vegetable oils or biodegradable oils instead of mineral oils are used as primary techniques to enhance the overall part quality, which leads to longer tool life with no negative impacts on the environment. To further help the manufacturing community in progressing towards industry 4.0 and obtaining net-zero emissions, in this paper, we present a comprehensive review of the recent, state of the art sustainable techniques used for machining steel materials/components by which the industry can massively improve their product quality and production

IoV-based Deployment and Scheduling of Charging Infrastructure in Intelligent Transportation Systems

Internet of vehicles (IoV) is an emerging paradigm to exchange and analyze information collected from sensors using wireless technologies between vehicles and people, vehicles and infrastructure, and vehicles-to-vehicles. With the recent increase in the number of electric vehicles (EVs), the seamless integration of IoV in EVs and charging infrastructure can offer environmentally sustainable and budget-friendly transportation. In this paper, we propose an IoV-based framework that consists of deployment and scheduling of a mobile charging infrastructure. For the deployment, we formulate an optimization problem to minimize the total cost of mobile charging infrastructure placement while considering constraints on the number of EVs that can be charged simultaneously. The formulated problem is mixedinteger programming and solved by using the branch and bound algorithm. We then propose an IoV-based scheduling scheme for EVs charging to minimize travel distance and charging costs while satisfying the constraints of charging time requirement of EVs and resources of a charging station.We consider passive road sensors and traffic sensors in the proposed IoV-based scheduling scheme to enable EV users for finding a charging station that can fulfill their requirements, as well as to enable service providers to know about the demand in the area. Simulation results illustrate the significant impact of the optimal deployment of charging infrastructure and scheduling optimization on the efficiency of EVs charging