The origin and composition of carbonatite-derived carbonate-bearing fluorapatite deposits

Carbonate-bearing fluorapatite rocks occur at over 30 globally distributed carbonatite complexes and represent a substantial potential supply of phosphorus for the fertiliser industry. However, the process(es) involved in forming carbonate-bearing fluorapatite at some carbonatites remain equivocal, with both hydrothermal and weathering mechanisms inferred. In this contribution, we compare the paragenesis and trace element contents of carbonate-bearing fluorapatite rocks from the Kovdor, Sokli, Bukusu, Catalão I and Glenover carbonatites in order to further understand their origin, as well as to comment upon the concentration of elements that may be deleterious to fertiliser production. The paragenesis of apatite from each deposit is broadly equivalent, comprising residual magmatic grains overgrown by several different stages of carbonate-bearing fluorapatite. The first forms epitactic overgrowths on residual magmatic grains, followed by the formation of massive apatite which, in turn, is cross-cut by late euhedral and colloform apatite generations. Compositionally, the paragenetic sequence corresponds to a substantial decrease in the concentration of rare earth elements (REE), Sr, Na and Th, with an increase in U and Cd. The carbonate-bearing fluorapatite exhibits a negative Ce anomaly, attributed to oxic conditions in a surficial environment and, in combination with the textural and compositional commonality, supports a weathering origin for these rocks. Carbonate-bearing fluorapatite has Th contents which are several orders of magnitude lower than magmatic apatite grains, potentially making such apatite a more environmentally attractive feedstock for the fertiliser industry. Uranium and cadmium contents are higher in carbonate-bearing fluorapatite than magmatic carbonatite apatite, but are much lower than most marine phosphorites

Design and development of a novel re-configurable fixturing system

SAE Technical Paper 2015-01-2495. 2015Modem aerospace industry is continuously seeking new technologies due to potential increase in demand for new aircrafts which are to be produced on a single production line while reducing model changeover time and improving quality of the assembly process. In mass volume production, this can be achieved by fixing a large number of similar components using special-purpose jigs and fixtures. This type of jigs and fixtures can be largely found in Aerospace industry. In low volume production, improvement of rc-configurablc fixturing systems becomes a favourable way to reduce the cost of production per unit. A re-configurable fixturing system consists of standard components that can be used to satisfy different fixturing requirements. These fixtures are reusable and this enhances their flexibility and reduces the time and cost of development. It also offers the benefit of eliminating the need for dedicated tooling, dedicated fixturing, associated storage and floor space. Re-configurable fixturing also provide rapid response to engineering and production changes, system expandability, and considerable reduction in setup time. In this research a novel concept of re-configurable fixturing system is developed and validated using a fully functional small scale prototype made out of standard parts that are widely available in the market. The developed system can be easily applied to other industries due to its flexibility and reconfigurability

Re-configurable supporting structures for aircraft industry

Aircraft industry is continuously seeking new technologies due to the competitive market and high demand. During maintenance and manufacturing practices, dedicated supporting structures are used to handle large parts of the aircraft. Manufacturing of a supporting structure is expensive and it requires longer lead time along with skilled work force. This research investigates the current methods used in supporting structures for aircraft assembly and maintenance purposes. Novel conceptual design models for different reconfigurable supporting structures are developed using 3D CAD software. The conceptual models are designed using standard parts which are readily available in the market. Each conceptual model is compared and contrasted according to their strengths and weaknesses. The most reliable conceptual models are identified by the easiness of assembling and disassembling in a shorter period of time. Furthermore, Finite Element Analysis (FEA) is used for further analyse the stress distribution, deformation and buckling tendency of proposed conceptual designs. Finally the safest and durable conceptual design is manufactured using widely available manufacturing processe

Fault detection and diagnosis of automobiles without obd systems

Early fault diagnosis for automobile engines is very important to ensure reliable operation of the engine. Most of e faults in an automobile engine cannot be detected externally. Detecting faults and its’ location, without dismantling the engme is very difficult. On-board diagnostic (OBD) systems in modem vehicles can be used to detect engine faults up to some extent.'However, OBD systems are not accurate enough in certain conditions and technicians having difficulties when interpretation of information. OBD method cannot be used for old vehicles. Hence, these factors necessitate the development of intelligent and accurate diagnosis method for troubleshooting automobile engine faults. Therefore, a mathematical model is developed to identify engine faults through the simulation of Instantaneous Angular Speed Fluctuation (IASF) of crank shaft. Three force components created by gas pressure, inertia of the moving parts and friction of the moving parts are used to generate the mathematical model. The parameters of the model are modified according to the potential faulty condition and IASF waveform is recorded and compared in different fault scenarios. Type of the fault and the severity of the fault are identified through the comparison. Experiments are conducted using a healthy automobile engine to validate the simulation results. The characteristic parameters for representing potential faults in an automobile engine and their relationship with IASF of the crank shaft are obtained for fault diagnosing. Furthermore a graphical user interface is developed to analyse instantaneous angular speed waveform which can be used as a real time engine condition monitoring system

<i>Toxoplasma gondii</i> seroprevalence among two selected groups of women

Toxoplasma gondii is an intracellular parasite able to cross the placental barrier and known to infect the foetal tissues leading to abortions and congenital deformities. This was a case control study conducted between April 2009 and 2010 that compared the seroprevalence of T. gondii and the frequency of association to known risk factors for infection between 100 healthy pregnant women within 28 weeks of pregnancy having no medical complications and 100 women having undergone a spontaneous miscarriage in the past 6 months attending the Antenatal and  Gynaecology clinics of the Professorial Obstetrics &amp; Gynaecology Unit of the De Soyza Maternity Hospital for Women in Colombo. Two milliliters of venous blood was collected and tested for T. gondii antibodies at the Department of Parasitology, Faculty of Medicine, Colombo, using OnSite Toxo IgG/IgM Rapid Test-Dip Strip®. Personal details and data regarding the known risk factors for the infection were obtained using an interviewer administered questionnaire. The participants were aged between 15 and 46 years (median 29); 38% of women in each group were primigravidae. All participants were sero-negative for anti-T. gondii IgM antibodies. However, 22.5% (n=45) of all study subjects were sero-positive for anti-T. gondii IgG antibodies, which included 62.2% (n=28) from the healthy group and 37.8% (n=17) from those with a recent past history of a spontaneous miscarriage. The difference in seropositivity for Toxoplasma gondii between the two selected groups was not statistically significant (X2=3.47; p=0.063). There were no significant associations between sero-positivity and known risk factors either (p&gt;0.05). Although our study did not reveal any evidence for association between exposure to Toxoplasma gondii infection and spontaneous miscarriage, the presence of more than 75% non-immune women of child bearing age is a cause for concern considering the potential risks posed by this parasite, emphasizing the importance of an organized educational programme targeting this high risk group to prevent infection during pregnancy.DOI: http://dx.doi.org/10.4038/sljid.v1i1.3091 Sri Lankan Journal of Infectious Diseases Vol.1(1) 2011: 9-17</p

Targeting voltage-gated calcium channels in neurological and psychiatric diseases

Voltage-gated calcium channels are important regulators of brain, heart and muscle functions, and their dysfunction can give rise to pathophysiological conditions ranging from cardiovascular disorders to neurological and psychiatric conditions such as epilepsy, pain and autism. In the nervous system, calcium channel blockers have been used successfully to treat absence seizures, and are emerging as potential therapeutic avenues for pathologies such as pain, Parkinson disease, addiction and anxiety. This Review provides an overview of calcium channels as drug targets for nervous system disorders, and discusses potential challenges and opportunities for the development of new clinically effective calcium channel inhibitors