Numerical Simulations of a High-Resolution RANS-FVDM Scheme for the Design of a Gas Turbine Centrifugal Compressor

The aero-thermodynamic design and performance of a compressor need to conquer many vital challenges like it is a gas-driven turbo-machinery component, involvement of extensive iterative process for the convergence of the design, enormous design complexity due to three-dimensional flow phenomena, and multiflow physics embedded within a dynamic state-of-the-art. In this chapter, a strong attempt is made to address the above-cited technical issues to achieve an optimized design and performance of a centrifugal compressor with backward swept blade profile producing total pressure ratio of 5.4 with an ingested mass flow rate of 5.73 kg/s. A mean-line design methodology was implemented to configure sizing of the compressor. An optimum grid size was well validated by carrying out computational analysis with three different mesh sizes within the same framework. Finally, a detailed three-dimensional numerical simulation was performed using Reynolds-averaged Navier-Stokes equations based on finite volume discretization method (RANS-FVDM) scheme. Consequently, the polytropic efficiency, total-to-total efficiency, stagnation pressure ratio at a fixed rotational speed, and the overall design and aero-thermodynamic performance of the centrifugal compressor are validated

Spindle cell sarcoma of sphenoid bone

Primary bone tumors involving skull are extremely rare and they constitute 0.8% of all bone tumors. The common tumors that are seen in skull base include fibrous dysplasia, giant cell tumor, chordoma, ossifying fibroma, angiosarcoma. We report a rare case of spindle cell sarcoma arising from right sphenoid bone in a 70-year-old male which presented as unilateral defective vision with mild proptosis

A review of antibiotic synergy in carbapenemase-producing bacteria

The problem of antibiotic resistance has garnered too much attention over the last few decades for posing a global hazard to the clinical handling and the inhibition of several deadly infections caused by bacteria. It burdens the world not only clinically but also economically... Antibiotic agents known as carbapenems are a very effective and  typically designated for the treatment of multidrug-resistant (MDR) bacterial infections. To identify a suitable antibiotic combination to be used in vivo, one must be able to determine the synergism between the antibiotics in vitro. Several methods, such as the checkerboard method, multiple-combination bactericidal test, time-kill and E-test, have been used for this purpose. However, the lack of proper standardization procedures, types of bacterial agents, bacterial load, stage of infection and other factors make it very difficult to reproduce or correlate the results with other methods.Carbapenem-destroying lactases, which have recently emerged as mechanisms of resistance, are increasing in number and decreasing the treatment alternatives available. These infections are treated with colistin and tigecycline, but monotherapy may result in clinical breakdown because of a variety of factors. To control these infections, clinicians often choose combinations of drugs over monotherapy. There is an extreme lack of information on synergistic antibiotic combinations accounting for the diverse mechanisms of GNB resistance commonly encountered. The incidence of carbapenem-resistant GNB in Indian articles is also unknown. Therefore, we anticipate that this study may provide methodology for the selection of an appropriate antibiotic combination

Using Barkhausen Noise to Measure Coating Depth of Coated High-Speed Steel

Coated high-speed steel tools are widely used in machining processes as they offer an excellent tool life to cost ratio, but they quickly need replacing once the coated layer is worn away. It would be therefore useful to be able to measure the tool life remaining non-destructively and cheaply. To achieve this, the work presented here aims to measure the thickness of the coated layer of high-speed cutting tools by using Barkhausen noise (BHN) techniques. Coated high-speed steel specimens coated with two different materials (chromium nitride (CrN), titanium nitride (TiN)) were tested using a cost-effective measuring system developed for this study. Sensory features were extracted from the signal received from a pick-up coil and the signal features, Root mean square, peak count, and signal energy, were successfully correlated with the thickness of the coating layer on high-speed steel (HSS) specimens. The results suggest that the Barkhausen noise measuring system developed in this study can successfully indicate the different thickness of the coating layer on CrN/TiN coated HSS specimens

Do absorption and realistic distraction influence performance of component task surgical procedure?

Background. Surgeons perform complex tasks while exposed to multiple distracting sources that may increase stress in the operating room (e.g., music, conversation, and unadapted use of sophisticated technologies). This study aimed to examine whether such realistic social and technological distracting conditions may influence surgical performance. Methods. Twelve medical interns performed a laparoscopic cholecystectomy task with the Xitact LC 3.0 virtual reality simulator under distracting conditions (exposure to music, conversation, and nonoptimal handling of the laparoscope) versus nondistracting conditions (control condition) as part of a 2 x 2 within-subject experimental design. Results. Under distracting conditions, the medical interns showed a significant decline in task performance (overall task score, task errors, and operating time) and significantly increased levels of irritation toward both the assistant handling the laparoscope in a nonoptimal way and the sources of social distraction. Furthermore, individual differences in cognitive style (i.e., cognitive absorption and need for cognition) significantly influenced the levels of irritation experienced by the medical interns. Conclusion. The results suggest careful evaluation of the social and technological sources of distraction in the operation room to reduce irritation for the surgeon and provision of proper preclinical laparoscope navigation training to increase security for the patient.Industrial DesignIndustrial Design Engineerin

Study of forced degradation behaviour of eprosartan mesylate and development of validated stability indicating assay method by UPLC

The present research work describes comprehensive stress testing of eprosartan mesylate (EM) according to ICH guideline Q1A (R2), and development of a stability-indicating reversed phase ultra performance liquid chromatographic (UPLC) assay. The drug was subjected to acid (0.5N HCl), neutral and alkaline (0.5 N NaOH) hydrolytic conditions at 80 °C, and to oxidative decomposition at room temperature. Photolysis was carried out by exposing the drug during the day time to sunlight (60,000-70,000 lux) for two days and oxidative study was performed with 0.5 mg/ml in 30 % hydrogen peroxide (H2O2 ) at room temperature for 25 hr. The solid drug was also subjected to 50 °C for 30 days in a hot air oven. Degradation of the drug was found to occur under alkaline, acidic and neutral hydrolytic conditions. Separation of the drug and the degradation products was successfully achieved on a BEH (bridged ethylene hybrid) C18 column (1.7 µm, 2.1 mm × 150 mm) with gradient elution of water-acetonitrile as mobile phase. The flow rate and detection wavelength were 0.1 ml/min and 232 nm, respectively. The method was validated and the response was found to be linear in the drug concentration range 5-25 µg/ml (r2 = 0.999). The %RSD in intra-day and inter-day precision studies was < 0.8 %. Recovery of the drug from a mixture of degradation products was between 98.3 and 99.8 %. The LOD and LOQ of developed method were obtained at 0.15 µg/ml and 0.45 µg/ml respectively. The method was specific to the drug, selective to degradation products, and robust. PDA purity test also confirmed the specificity of the method.Colegio de Farmacéuticos de la Provincia de Buenos Aire