Melting of PCM in a thermal energy storage unit: Numerical investigation and effect of nanoparticle enhancement

The present paper describes the analysis of the melting process in a single vertical shell-and-tube latent heat thermal energy storage (LHTES), unit and it is directed at understanding the thermal performance of the system. The study is realized using a computational fluid-dynamic (CFD) model that takes into account of the phase-change phenomenon by means of the enthalpy method. Fluid flow is fully resolved in the liquid phase-change material (PCM) in order to elucidate the role of natural convection. The unsteady evolution of the melting front and the velocity and temperature fields is detailed. Temperature profiles are analyzed and compared with experimental data available in the literature. Other relevant quantities are also monitored, including energy stored and heat flux exchanged between PCM and HTF. The results demonstrate that natural convection within PCM and inlet HTF temperature significantly affects the phase-change process. Thermal enhancement through the dispersion of highly conductive nanoparticles in the base PCM is considered in the second part of the paper. Thermal behavior of the LHTES unit charged with nano-enhanced PCM is numerically analyzed and compared with the original system configuration. Due to increase of thermal conductivity, augmented thermal performance is observed: melting time is reduced of 15% when nano-enhanced PCM with particle volume fraction of 4% is adopted. Similar improvements of the heat transfer rate are also detecte

Transcriptional profiling of macrophages in situ in metastatic melanoma reveals localization-dependent phenotypes and function.

Modulation of immune function at the tumor site could improve patient outcomes. Here, we analyze patient samples of metastatic melanoma, a tumor responsive to T cell-based therapies, and find that tumor-infiltrating T cells are primarily juxtaposed to CD14+ monocytes/macrophages rather than melanoma cells. Using immunofluorescence-guided laser capture microdissection, we analyze transcriptomes of CD3+ T cells, CD14 + monocytes/macrophages, and melanoma cells in non-dissociated tissue. Stromal CD14+ cells display a specific transcriptional signature distinct from CD14+ cells within tumor nests. This signature contains LY75, a gene linked with antigen capture and regulation of tolerance and immunity in dendritic cells (DCs). When applied to TCGA cohorts, this gene set can distinguish patients with significantly prolonged survival in metastatic cutaneous melanoma and other cancers. Thus, the stromal CD14+ cell signature represents a candidate biomarker and suggests that reprogramming of stromal macrophages to acquire DC function may offer a therapeutic opportunity for metastatic cancers

Model based optimization of axial piston machines focusing on noise and efficiency

Noise problem in swash plate type axial piston pumps is well known in the fluid power industry and several approaches have been reported in the past regarding reducing the noise sources in the pump. In this work two such approaches, namely, relief grooves and precompression filter volume have been investigated in detail. As a result of the investigation, a computer based optimization procedure has been developed to assist pump designers to optimize the rotating group design, especially the valve plate, that will achieve reduction in both fluid borne and structure borne sources of noise in a wide range of operating condition thereby providing quieter operating of the pump. The developed optimization procedure simultaneously considers both compression and expansion regions while optimizing valve plate design. The optimization procedure has been proven using a case study and noise level measurements. Also, a combination technique that includes relief grooves and precompression filter volume attached with relief grooves has also been proposed and the combination technique promises to have the quietest possible operation of the pump in a wide operating range

Holdup and solids circulation rate in liquid-solids circulating fluidised bed

247-254Experimental data, obtained using liquid-solids circulating fluidised bed, are presented to study the influence of liquid flow rate and the solids properties on the solids velocity and holdup in the riser. The influence of the auxiliary liquid flow facilitating the solids feed into the riser, and that of primary liquid flow providing the solids transport in the riser are clearly examined and correlations are presented for the holdup and the solids circulation rate based on the present data and the data reported in literature

Outcome of Liver Resection for Liver Tumours in Children: An Institutional Review from a Developing Country

Availability of gadgets like Harmonic Scalpel allows liver resection to be performed with ease andminimal blood loss. The scenario is different in a developing country which lacks these modern gadgets. We present a review of our results of liver resection from a referral institute in a developing country. We reviewed children with liver resection done at our Institute from July 1999 - July 2006. Children with liver trauma and non operated tumour cases were excluded. Twenty one resections were carried out in 7 years, achieving a 68.4% disease free survival rate. The most common presenting complaint was abdominal mass (19 /21-90%). The majority (85%, 18/21) were found to be malignant on histopathological examination. Anatomical resections were performed in 16 (85%) children; 4 developed tumour recurrence, 3 with recurrence did not respond to second line chemotherapy and diedwhilewaiting for reoperation. One with recurrent liver tumour refused further treatment.Two (10%)were lost to followup. Liver resections can be safely performed in the absence of the modern gadgets, although presence of such gadgets would facilitate resection in terms of operating time and blood loss. Keywords: Liver resection, paediatric liver tumours, outcomeAfrican Journal of Paediatric Surgery Vol. 4 (1) 2007: pp. 3-