The Numerical Comparison of Heat Transfer in a Coated and Fixed Bed of an Adsorption Chiller

Ecological adsorption technology is becoming a focus of attention by industry due to the utilization of low grade thermal energy sources for cooling production. It can be a promising part of sustainable development concept of the global economy. Therefore, research aiming at improving their performance i.e. Coefficient of Performance (COP) by optimizing the construction of sorption beds with a built in heat exchanger system is crucial. The heat transfer characteristics between the bed of porous media (sorbent) and surface of the heat exchanger system determine the heating power of an adsorption chiller. The HP increase can be obtained by heat transfer intensification due to the increase in the thermal conductivity of the sorbent layer in the vicinity of the heat exchanger’s surface. The novel modification of the sorbent layer structure is proposed in the paper in order to improve the heat transfer processes in the heat exchanger boundary layer. The analysis of desorption process conditions in the parametric model of a coated and fixed adsorption bed design is presented in the paper. The computational fluid dynamics (CFD) with conjugate heat transfer analysis is used to determine the crucial input parameters (temperature distribution in the sorbent bed) for further analytical calculations. The commercial code Ansys Fluent was used to perform numerical simulations. The developed computational model consisted of three subdomains representing heating water, heat exchanger material (copper) and sorbent (silica gel). The comparison of a novel coated design and a conventional fixed bed is discussed in the paper. The numerical analysis is based on experimental thermal conductivity measurements of the sorbent layer in different configurations, which were performed using Laser Flash Method.     

Molecular analysis of mammalian timeless

We cloned the mouse cDNA of a mammalian homolog of the Drosophila timeless (tim) gene and designated it mTim. The mTim protein shows five homologous regions with Drosophila TIM. mTim is weakly expressed in the suprachiasmatic nuclei (SCN) but exhibits robust expression in the hypophyseal pars tuberalis (PT). mTim RNA levels do not oscillate in the SCN nor are they acutely altered by light exposure during subjective night. mTim RNA is expressed at low levels in several peripheral tissues, including eyes, and is heavily expressed in spleen and testis. Yeast two-hybrid assays revealed an array of interactions between the various mPER proteins but no mPER-mTIM interactions. The data suggest that PER-PER interactions have replaced the function of PER-TIM dimers in the molecular workings of the mammalian circadian clock.     

Three period homologs in mammals: differential light responses in the suprachiasmatic circadian clock and oscillating transcripts outside of brain

We have cloned and characterized the mouse cDNA of a third mammalian homolog of the Drosophila period gene and designated it mPer3. The mPER3 protein shows approximately 37% amino acid identity with mPER1 and mPER2 proteins. The three mammalian PER proteins share several regions of sequence homology, and each contains a protein dimerization PAS domain. mPer3 RNA levels oscillate in the suprachiasmatic nuclei (SCN) and eyes. In the SCN, mPer3 RNA levels are not acutely altered by light exposure at different times during subjective night. This contrasts with the acute induction by light of mPer1 and mPer2 RNA levels during early and late subjective night. mPer3 is widely expressed in tissues outside of brain. In liver, skeletal muscle, and testis, mPer RNAs exhibit prominent, synchronous circadian oscillations. The results highlight the differential light responses among the three mammalian Per genes in the SCN and raise the possibility of circadian oscillators in mammals outside of brain and retina.     

The EASI project-improving the effectiveness and quality ofimage-guided surgery

In recent years, advances in computer technology and a significant increase in the accuracy of medical imaging have made it possible to develop systems that can assist the clinician in diagnosis, planning, and treatment. This paper deals with an area that is generally referred to as computer-assisted surgery, image-directed surgery, or image-guided surgery. We report the research, development, and clinical validation performed since January 1996 in the European Applications in Surgical Interventions (EASI) project, which is funded by the European Commission in their “4th Framework Telematics Applications for Health” program. The goal of this project is the improvement of the effectiveness and quality of image-guided neurosurgery of the brain and image-guided vascular surgery of abdominal aortic aneurysms, while at the same time reducing patient risks and overall cost. We have developed advanced prototype systems for preoperative surgical planning and intraoperative surgical navigation, and we have extensively clinically validated these systems. The prototype systems and the clinical validation results are described in this paper     

Effect of irradiation on glycosaminoglycans content in rat tissue

Glycosaminoglycan (GAGs) fractions were determined in tissues (skin, liver, lungs, aortic wall) and blood serum of rats irradiated with a single dose of 500 R. An increase of total GAGs as well as changes in the fractions were found in the tissues and urine of exposed rats.     

Latest NIKA Results and the NIKA-2 Project

NIKA (New IRAM KID Arrays) is a dual-band imaging instrument installed at the IRAM (Institut de RadioAstronomie Millimetrique) 30-meter telescope at Pico Veleta (Spain). Two distinct Kinetic Inductance Detectors (KID) focal planes allow the camera to simultaneous image a field-of-view of about 2 arc-min in the bands 125 to 175 GHz (150 GHz) and 200 to 280 GHz (240 GHz). The sensitivity and stability achieved during the last commissioning Run in June 2013 allows opening the instrument to general observers. We report here the latest results, in particular in terms of sensitivity, now comparable to the state-of-the-art Transition Edge Sensors (TES) bolometers, relative and absolute photometry. We describe briefly the next generation NIKA-2 instrument, selected by IRAM to occupy, from 2015, the continuum imager/polarimeter slot at the 30-m telescope.     

The influence of end mill helix angle on high performance milling process

The results of experimental research on the influence of the helix angle on high performance milling of AlZn5.5MgCu alloy are presented. End mills with a wavy shape of a cutting edge, dedicated to rough high performance machining, were used. The helix angle was changed in the range of 20° to 50° with a step of 5°. During the milling tests, three cutting force components were measured. After each test cutting, chips were collected and analyzed. A recording of the chip evacuation process using a high-speed camera was also conducted. The influence of the helix angle on cutting force components was determined and the mathematical models of the forces were calculated. The significance of coefficients in the obtained equations was analyzed as well. The recorded images of the chip evacuation were analyzed. The displacement and the angle of the chip evacuation were determined. Based on the analysis of the selected images the impact of the helix angle on the direction and evacuation velocity of chips was determined. The size and shape of the obtained chips was also analyzed.