Energy and exergy analysis of fuel cells: a review

In this paper, the fundamental overview of theoretical and practical aspects of thermodynamics analysis for mainly used fuel cells (FCs) are presented. The FC converts the chemical energy of fuel (normally hydrogen) directly into electrical energy resulting heat and liquid water as a waste products. In first part, governing equation of mass, energy, entropy and exergy are presented according to first law of thermodynamics (FLT) and second law of thermodynamics (SLT), more specifically energy and exergy analysis are covered for fuel cell system. Basic criteria of energy and exergy analysis of flowing and non-flowing system, energy and exergy efficiencies, analysis procedure and models of reference environment are discussed in detail. In the second part, electrochemical reactions and thermodynamics modeling of proton exchange membrane or polymer electrolyte membrane fuel cell (PEMFC), solid oxide fuel cell (SOFC), and molten carbonate fuel cell (MCFC) are presented

Analysis of Population Dynamics of Terrorist Cells

Applied mathematics connects many different fields of science. This research focuses on the population dynamics of terrorist organizations, namely Al Qaeda, by creating a mathematical model, while still considering social science fields, such as psychology. By considering psychological interrelations of a terrorist cell and their contact with citizens, we design a model that is a four-dimensional system of nonlinear differential equations to better understand the way in which recruitment ensues within such organizations. Using the computer program Mathematica, we are able to manipulate multiple parameters simultaneously in order to observe the impact of certain recruitment techniques on the general population. This results in either the absorption of the human race by the terrorist organization, or more positively, a ceiling on the terrorist population. Other scientists, such as psychologists, can use this information to implement new strategies to combat terrorism from a new intellectual perspective

Analysis of the interaction and proliferative activity of adenocarcinoma, peripheral blood mononuclear and mesenchymal stromal cells after co-cultivation in vitro

The tumor microenvironment is a heterogeneous population of cells actively involved in the process of growth and development of a tumor. Research has demonstrated the interactions between the different populations of cells are critical for the formation of the tumor microenvironment and, if recapitulated experimentally, can be used to produce more effective models for preclinical screening of anticancer drugs. In this study, we demonstrate co-culturing HeLa adenocarcinoma cells, peripheral blood mononuclear cells, and mesenchymal stromal cells results in changes in the proliferative activity of the peripheral blood mononuclear cells and mesenchymal stromal cell populations. This data supports the further development of in vitro co-culture systems utilizing these cell types for pre-clinical screening of anticancer drugs

Multimodal Image Analysis of Chronic Leukemic Lymphoproliferative Disorders and the Hypothesis of »Single« and »Multiple« Programmed Stops in the Development of Typical and Atypical Forms of Leukemias and Lymphomas

The study consisted of morphometric analysis, assessment of the argyrophilic nucleolar organization region (AgNOR) characteristics, and image cytometry (ICM) in different tumor mass compartments: bone marrow (BM), peripheral blood (PB) and lymph nodes (LN) from patients with chronic leukemic lymphoproliferative disorders. A total of 71895 cells were analyzed on SFORM PC (VAMSTEC, Zagreb). Correlation between morphometric, AgNOR and ICM characteristics revealed the cells with low proliferative activity to possess small, homogeneous AgNOR, with the majority of cells in the peak of DNA histogram. The cells with high proliferative activity had inhomogeneous AgNOR, mostly containing greater DNA content than peak cells, pathologic mitoses (DNA>4N), or the majority of cells were in the S-phase of the cell cycle. Cells with medium proliferative activity and annular AgNOR were in-between. Analysis of different tumor mass compartments showed that lymphatic cells with the affinity to accumulate in BM regularly exhibited low proliferative activity (a lower percentage of cells in SFC and highest percentage of cells in the peak of the G0/G1 phase). The cells in LN exhibited the characteristics of proliferative cells (an increased number of AgNOR, larger and more proliferative inhomogeneous AgNOR, and lowest percentage of cells in the G0/G1 phase). The migration of cells from BM to LN and between lymph nodes occurred through PB (there were cells with low and high proliferative activity: a higher proportion of cells in SFC and at the same time in the G0/G1 phase of the cell cycle). Analysis of cell size and proliferative activity in different compartments of tumor mass revealed that the cells in BM and PB did not differ substantially according to size and proliferative activity, while an inverse pattern was observed between PB and LN. As small cells are inactive and larger cells more proliferative, the analysis quite unexpectedly showed the PB cells to be largest and most inactive, in contrast to LN where the cells were smallest and most active. The »single« and »multiple programmed stops« have been hypothesized in the development of typical forms of leukemias and lymphomas and atypical forms of subacute and subchronic leukemias. Differentiation impairment may occur at any stage, and different »stop« locations result in different morphology and affinity to accumulation in bone marrow, peripheral blood and lymph nodes