Continuum Thermodynamic Modeling and Simulation of Electromagnetic Metal Forming

The purpose of this work is the formulation and application of a continuum field approach to the phenomenological modeling of a class of engineering materials which can be dynamically formed using strong magnetic fields. This is done in the framework of a thermodynamic, internal-variable-based formulation in which the deformation, temperature and magnetic fields are in general coupled. As is well-known, this coupling takes the form of the Lorentz force as an additional supply of momentum, and the electromotive power as an additional supply of energy, in the material. The constitutive formulation is based as usual on the exploitation of the dissipation principle, here for the case of generally anisotropic, elastoviscoplastic material behaviour. In particular, the general results so obtained are applied in particular to the case of small strain and large rotation. As shown here, in this special case, the electromagnetic field relations become independent of the deformation field. As such, they can be solved independently and used as input for the solution of the thermomechanical field relations. Application of this reduced formulation for small strain to the simulation of the electromagnetic forming of an aluminum tube shows the importance of accounting for inertial effects and rate-dependence in the modeling

Automation design for monorail-based system processes

Currently, conventional methods of decline development put enormous cost pressure on the profitability of mining operations. This is the case with narrow vein ore bodies where current methods and mine design of decline development may be too expensive to support economic extraction of the ore. According to studies, the time it takes to drill, clean and blast an end in conventional decline development can be up to 224 minutes. This is because once an end is blasted, cleaning should first be completed before drilling can commence, resulting in low advance rates per shift. Improvements in advance rates during decline development can be achieved by application of the Electric Monorail Transport System (EMTS) based drilling system. The system consists of the drilling and loading components that use monorail technology to drill and clean the face during decline development. The two systems work simultaneously at the face in such a way that as the top part of the face is being drilled the pneumatic loading system cleans the face. However, to improve the efficiency of the two systems, critical processes performed by the two systems during mining operations must be automated. Automation increases safety and productivity, reduces operator fatigue and also reduces the labour costs of the system. The aim of this paper is, therefore, to describe automation designs of the two processes performed by the monorail drilling and loading systems during operations. During automation design, critical processes performed by the two systems and control requirements necessary to allow the two systems execute such processes automatically have also been identified

Multifunctional attributes of endophytic Pseudomonas strains isolated from the leaves of medicinal plants

Endophytic bacteria are responsible for improved plant growth due to its role in nitrogen fixation, indole acetic acid (IAA) production, phosphate solubilization etc and in plant protection through various mechanisms and production of bioactive compounds. The purpose of this study was to determine the plant growth promoting potential of endophytic bacteria isolated from medicinal plants namely, Adulsa, Amla, Bael, Kadamb, Mango, Neem, Tulsi. Endophytic bacteria isolated from the medicinal plants, comprised of 68% Gram positive and 29% Gram negative bacteria. Seventeen distinctly unique Gram-negative endophytes were selected for further analysis. The selected endophytes were tentatively identified as Pseudomonas sp. The multifarious endophytes were capable of nitrogen fixation, phosphate solubilisation, indole acetic acid (IAA) production, production of antimicrobial compounds and aromatic compound degradation. Some of the endophytic strains were found to harbor plasmids that may play a role in aromatic compound degradation. This study emphasizes the potential of endophytic Pseudomonas species in enhancing plant growth and plant protection

Emergency Contraception Among Women With Abortion At University Teaching Hospital In Lusaka, Zambia

Background: The maternal mortality ratio for Zambia is 591/100 000 live births. Globally between 15 – 30% of the maternal deaths are due to unsafe abortions. According to the Zambian demographic health survey (ZDHS), the contraceptive prevalence rate was 34% (CSO, 2003). The unmet need for family planning was 27%. Emergency contraception pill (ECP) was officially launched in Zambia in 1998 by the Ministry of Health with the aim of strengthening reproductive health. It can be obtained free of charge at public health institutions and also as an over the counter drug.Objective: To determine knowledge, Practice and attitude towards Emergency Contraception (EC) among women with abortion at the University Teaching Hospital (UTH), Lusaka, Zambia.Design: A cross-sectional descriptive study design and an interview schedule were administered to 200 women admitted to UTH with abortion aged between 18 – 49 years old.Main outcome measure: Emergency contraception awareness among women with abortions at UTH, Lusaka.Results: The median age of the participants was 19 years. Only 7.5% had ever heard of emergency contraceptive pills (ECPs). Majority (70%) were married with the majority reporting being married for less than 5 years. The contraceptive ever use rate was 78.5%and 58% the participants had their first pregnancies as teenagers. Almost a third (31%) was nulliparous. The most common sources of information about EC were friends (80%). Level of education was significantly associated with the outcome of EC awareness (OR = 9.5; 95% CI [3.06 – 29.87] (P value 0.001). Another factor that was significantly associated with the outcome of EC awareness was the level of EC knowledge (OR = 0.00; 95% CI [0.00 – 0.02](P value 0.001). Other factors such as age, place of residence and marital status were not significantly associated with EC awareness.Conclusion: Knowledge about Emergency Contraception (EC) among women with abortions admitted to UTH is low. Friends are an important source of EC information. Awareness and knowledge of EC should be increased

To freeze or not to: Quantum correlations under local decoherence

We provide necessary and sufficient conditions for freezing of quantum correlations as measured by quantum discord and quantum work deficit in the case of bipartite as well as multipartite states subjected to local noisy channels. We recognize that inhomogeneity of the magnetizations of the shared quantum states plays an important role in the freezing phenomena. We show that the frozen value of the quantum correlation and the time interval for freezing follow a complementarity relation. For states which do not exhibit "exact" freezing, but can be frozen "effectively", by having a very slow decay rate with suitable tuning of the state parameters, we introduce an index -- the freezing index -- to quantify the goodness of freezing. We find that the freezing index can be used to detect quantum phase transitions and discuss the corresponding scaling behavior.Comment: 14 pages, 9 figures, close to published version, title changed by Phys. Rev. A. to 'Freezing of quantum correlations under local decoherence