Hydrodynamics Characteristics and Gas-Liquid Mass Transfer in a Three Phase Fluidized Bed Reactor

This paper presents the experimental characterization of hydrodynamics and gas-liquid mass transfer in a three-phase fluidized bed containing polystyrene and nylon particles. The influence of gas and liquid velocities on phase holdups and volumetric gas-liquid mass transfer coefficient was investigated for flow conditions similar to those applied in biotechnological process. The phase holdups were obtained by the pressure profile technique. The volumetric gas-liquid mass transfer coefficient was obtained adjusting the experimental concentration profiles of dissolved oxygen in the liquid phase with the predictions of the axial dispersion model. According to experimental results the liquid holdup increases with the gas velocity, whereas the solid holdup decreases. The gas holdup increases significantly with the increase in gas velocity, and it shows for the three-phase fluidized bed comparable values or larger than those of bubble column. The volumetric gas-liquid mass transfer coefficient increases significantly with an increase in the air velocity for both bubble column and fluidized beds. In addition, in the operational condition of high liquid velocity, the presence of low-density particles in the bed increased the gas-liquid mass transfer, and thus the volumetric mass transfer coefficient values obtained in the fluidized bed were comparable or larger than those of bubble column.

Simulation of Steady-State Nonlinear Heat Transfer Problems Through the Minimization of Quadratic Functionals

In this work it is presented a systematic procedure for constructing the solution of a large class of nonlinear conduction heat transfer problems through the minimization of quadratic functionals like the ones usually employed for linear descriptions. The proposed procedure gives rise to an efficient and easy way for carrying out numerical simulations of nonlinear heat transfer problems by means of finite elements. To illustrate the procedure a particular problem is simulated by means of a finite element approximation.

Effects of condensation in microchannels with a porous boundary: analytical investigation on heat transfer and meniscus shape

In two-phase miniature and microchannel flows, the meniscus shape must be considered due to effects that are affected by condensation and/or evaporation and coupled with the transport phenomena in the thin film on the microchannel wall, when capillary forces drive the working fluid. This investigation presents an analytical model for microchannel condensers with a porous boundary, where capillary forces pump the fluid. Methanol was selected as the working fluid. Very low liquid Reynolds numbers were obtained (Re~6), but very high Nusselt numbers (Nu~150) could be found due to the channel size (1.5 mm) and the presence of the porous boundary. The meniscus calculation provided consistent results for the vapor interface temperature and pressure, as well as the meniscus curvature. The obtained results show that microchannel condensers with a porous boundary can be used for heat dissipation with reduced heat transfer area and very high heat dissipation capabilities.

Homogeneous assay technologies in drug screening: Quenching Resonance Energy Transfer (QRET) technique

Information gained from the human genome project and improvements in compound synthesizing have increased the number of both therapeutic targets and potential lead compounds. This has evolved a need for better screening techniques to have a capacity to screen number of compound libraries against increasing amount of targets. Radioactivity based assays have been traditionally used in drug screening but the fluorescence based assays have become more popular in high throughput screening (HTS) as they avoid safety and waste problems confronted with radioactivity. In comparison to conventional fluorescence more sensitive detection is obtained with time-resolved luminescence which has increased the popularity of time-resolved fluorescence resonance energy transfer (TR-FRET) based assays. To simplify the current TR-FRET based assay concept the luminometric homogeneous single-label utilizing assay technique, Quenching Resonance Energy Transfer (QRET), was developed. The technique utilizes soluble quencher to quench non-specifically the signal of unbound fraction of lanthanide labeled ligand. One labeling procedure and fewer manipulation steps in the assay concept are saving resources. The QRET technique is suitable for both biochemical and cell-based assays as indicated in four studies:1) ligand screening study of β2 -adrenergic receptor (cell-based), 2) activation study of Gs-/Gi-protein coupled receptors by measuring intracellular concentration of cyclic adenosine monophosphate (cell-based), 3) activation study of G-protein coupled receptors by observing the binding of guanosine-5’-triphosphate (cell membranes), and 4) activation study of small GTP binding protein Ras (biochemical). Signal-to-background ratios were between 2.4 to 10 and coefficient of variation varied from 0.5 to 17% indicating their suitability to HTS use.

Lymph node transfer in the treatment of postmastectomy lymphedema

Background: Lymphedema is a debilitating disorder with few treatment options. Clinical studies have shown that microvascular lymph node transfer may improve the lymphatic function of the affected limb. This study provides information about the clinical efficacy and safety of this procedure. Further, the biological background of this technique is clarified with an analysis of postoperative production of lymphatic growth factors and cytokines related to lymphangiogenesis. Patients and Methods: The effect of lymph node transfer to recipient and donor sites was analyzed with lymphoscintigraphy, limb circumference measurements, and appearance of clinical symptoms. Axillary seroma samples were analyzed from four patient groups: Axillary lymph node removal (ALND), Microvascular breast reconstruction (BR), lymph node transfer (LN) and combined lymph node transfer and breast reconstruction (LN-BR). Results: The postoperative lymphatic transport index was improved in 7/19 patients. Ten patients were able to reduce or discontinue compression therapy 6 - 24 months postoperatively. The donor lower limb lymphatic flow was slightly impaired (Ti >10) in 2 patients. No donor site lymphedema symptoms appeared during the 8 – 56-month follow-up. A high concentration of the VEGF-C protein was detected in the seroma fluid of all flap transfer groups. The concentration of the anti-inflammatory and anti-fibrotic cytokine IL-10 was increased in the LN-BR group samples when compared to the ALND or BR group. Conclusions: According to this preliminary study, the lymph node transfer seems to be beneficial for the lymphedema patients. However, a randomized study comparing the effect of BR and LN-BR is needed to evaluate the clinical efficacy of lymph node transfer. In addition, the effect of this surgery on the donor site needs to be studied further. The clinical effects of the lymph node transfer might be partly mediated by increased production of the lymphangiogenic growth factor (VEGF-C) as well as the anti-fibrotic cytokine (IL-10).

Transfer pricing documentation differences in Finland and China - Case company study

This Master’s Thesis deals with the topic of transfer pricing documentation in Finland and China. The goal of the research is to find what kind of differences exist in a single case company’s transfer pricing documentation when following Chinese or Finnish transfer pricing regulations. The study is carried out as a case study research. The theoretical framework consists of information from different transfer pricing topics and transfer pricing documentation regulations in China and Finland. The main research material was the case company’s transfer pricing documents with the support of open discus-sion with one of the case company’s employees. The study compared the 2009 and 2010 documents. The 2009 document was done based on the Finnish method while the 2010 document was based on the Chinese documentation principles. The conclusion made is that the content of the documents was heavily similar, while the main differences come in the way the content is presented and the level of detail used in the documents.

Russian SME technology transfer to Finland – Entrepreneurial challenges and motivation

The purpose of this thesis is to study the international technology transfer of transition economy SME entrepreneurs to the developed countries. The research aims to characterize the phenomenon by studying Russian SME technology transfer to Finland with the research methods from case studies. In addition to characterizing the phenomenon, the research finds out factors that motivate Russian entrepreneurs to conduct international technology transfer and what are the challenges the Russian entrepreneurs face when they enter the Finnish business environment. The qualitative data was collected from six semi-structured interviews with the entrepreneurs and several secondary data sources, considering four different technology transfer cases. The data and the analysis showed that the case companies in Finland are mostly linked to manufacturing of physical products. The entrepreneurs are motivated to come to Finland mainly by the opportunities and support the Finnish business and innovation environment provides to the entrepreneurs and by the personal gain that they get by establishing the company in Finland. Major challenges in the process include time constraints and capital requirements, difficulties on achieving sales on the Finnish market and finding skilled personnel to support the Russian management and owners.

Ydinvoimalaitosten vesikemia ja korroosionesto

Ydinvoimalaitosten vesikemian optimointi ja korroosionesto on välttämätöntä laitosten taloudellisen ja turvallisen käytön kannalta. Eri laitoksiin liittyvää vesikemiaa ja järjestelmissä havaittavia korroosion muotoja on tutkittu laajasti ja tutkitaan yhä edelleen. Monien prosessien ymmärtäminen vaatii usean eri tieteenalan osaamista, kuten kemiantekniikan, energiatekniikan sekä materiaalitekniikan. Tässä työssä kerrotaan yksinkertaistaen vesikemiaan ja korroosioon liittyviä prosesseja ja reaktioita. Työssä käsitellään kevytvettä jäähdytteenä sekä moderaattorina käyttävien ydinvoimalaitosten eri korroosiomuotoja sekä säteilyn vaikutusta näihin suoraan tai vesikemian kautta. Työssä kerrotaan korroosio- ja aktivoitumistuotteiden muodostumisesta ja kulkeutumisesta sekä näiden tuotteiden vaikutuksista laitosten toimintaan. Korroosion ja materiaalien aktivoitumisen pohjalta tarkastellaan kattavasti ydinvoimalaitosten tyypillisimpiä vesikemian muokkauskeinoja sekä korroosionhallintaa. Tärkeimpiin asioihin syvennytään hieman lähemmin. Tarkastelun kohteena ovat eniten käytetyt ydinvoimalaitokset, eli länsimaiset paine- ja kiehutusvesilaitokset sekä venäläisvalmisteiset VVER-laitokset. Tarkoituksena on ollut luoda tiivis tietopaketti opiskelijoiden käyttöön muun opintomateriaalin tueksi.

Reference values for lung function tests: III. Carbon monoxide diffusing capacity (transfer factor)

Carbon monoxide diffusing capacity (DLCO) or transfer factor (TLCO) is a particularly useful test of the appropriateness of gas exchange across the lung alveolocapillary membrane. With the purpose of establishing predictive equations for DLCO using a non-smoking sample of the adult Brazilian population, we prospectively evaluated 100 subjects (50 males and 50 females aged 20 to 80 years), randomly selected from more than 8,000 individuals. Gender-specific linear prediction equations were developed by multiple regression analysis with single breath (SB) absolute and volume-corrected (VA) DLCO values as dependent variables. In the prediction equations, age (years) and height (cm) had opposite effects on DLCOSB (ml min-1 mmHg-1), independent of gender (-0.13 (age) + 0.32 (height) - 13.07 in males and -0.075 (age) + 0.18 (height) + 0.20 in females). On the other hand, height had a positive effect on DLCOSB but a negative one on DLCOSB/VA (P<0.01). We found that the predictive values from the most cited studies using predominantly Caucasian samples were significantly different from the actually measured values (P<0.05). Furthermore, oxygen uptake at maximal exercise (VO2max) correlated highly to DLCOSB (R = 0.71, P<0.001); this variable, however, did not maintain an independent role to explain the VO2max variability in the multiple regression analysis (P>0.05). Our results therefore provide an original frame of reference for either DLCOSB or DLCOSB/VA in Brazilian males and females aged 20 to 80 years, obtained from the standardized single-breath technique.