Exergetic analysis of an aircraft turbojet engine with an afterburner

An exergy analysis is reported of a J85-GE-21 turbojet engine and its components for two altitudes: sea level and 11,000 meters. The turbojet engine with afterburning operates on the Brayton cycle and includes six main parts: diffuser, compressor, combustion chamber, turbine, afterburner and nozzle. Aircraft data are utilized in the analysis with simulation data. The highest component exergy efficiency at sea level is observed to be for the compressor, at 96.7%, followed by the nozzle and turbine with exergy efficiencies of 93.7 and 92.3%, respectively. At both considered heights, reducing of engine intake air speed leads to a reduction in the exergy efficiencies of all engine components and overall engine. The exergy efficiency of the turbojet engine is found to decrease by 0.45% for every 1°C increase in inlet air temperature

Galaxies in box: A simulated view of the interstellar medium

We review progress in the development of physically realistic three dimensional simulated models of the galaxy.We consider the scales from star forming molecular clouds to the full spiral disc. Models are computed using hydrodynamic (HD) or magnetohydrodynamic (MHD) equations and may include cosmic ray or tracer particles. The range of dynamical scales between the full galaxy structure and the turbulent scales of supernova (SN) explosions and even cloud collapse to form stars, make it impossible with current computing tools and resources to resolve all of these in one model. We therefore consider a hierarchy of models and how they can be related to enhance our understanding of the complete galaxy.Comment: Chapter in Large Scale Magnetic Fields in the Univers

Energy End-Use : Industry

The industrial sector accounts for about 30% of the global final energy use and accounts for about 115 EJ of final energy use in 2005. 1Cement, iron and steel, chemicals, pulp and paper and aluminum are key energy intensive materials that account for more than half the global industrial use. There is a shift in the primary materials production with developing countries accounting for the majority of the production capacity. China and India have high growth rates in the production of energy intensive materials like cement, fertilizers and steel (12–20%/yr). In different economies materials demand is seen to grow initially with income and then stabilize. For instance in industrialized countries consumption of steel seems to saturate at about 500 kg/capita and 400–500 kg/capita for cement. The aggregate energy intensities in the industrial sectors in different countries have shown steady declines – due to an improvement in energy efficiency and a change in the structure of the industrial output. As an example for the EU-27 the final energy use by industry has remained almost constant (13.4 EJ) at 1990 levels. Structural changes in the economies explain 30% of the reduction in energy intensity with the remaining due to energy efficiency improvements. In different industrial sectors adopting the best achievable technology can result in a saving of 10–30% below the current average. An analysis of cost cutting measures for motors and steam systems in 2005 indicates energy savings potentials of 2.2 EJ for motors and 3.3 EJ for steam. The payback period for these measures range from less than 9 months to 4 years. A systematic analysis of materials and energy flows indicates significant potential for process integration, heat pumps and cogeneration for example savings of 30% are seen in kraft, sulfite, dairy, chocolate, ammonia, and vinyl chloride. An exergy analysis (second law of thermodynamics) reveals that the overall global industry efficiency is only 30%. It is clear that there are major energy efficiency improvements possible through research and development (R&D) in next generation processes. A comparison of energy management policies in different countries and a summary of country experiences, program impacts for Brazil, China, India, South Africa shows the features of successful policies. Energy management International Organization for Standardization (ISO) standards are likely to be effective in facilitating industrial end use efficiency. The effective use of demand side management can be facilitated by combination of mandated measures and market strategies. A frozen efficiency scenario is constructed for industry in 2030. This implies a demand of final energy of 225 EJ in 2030. This involves an increase of the industrial energy output (in terms of Manufacturing Value Added (MVA)) by 95% over its 2005 value. Due to normal efficiency improvements the Business as Usual scenario results in a final energy demand of 175 EJ. The savings possibilities in motors and steam systems, process improvements, pinch, heat pumping and cogeneration have been computed for the existing industrial stock and for the new industries. An energy efficient scenario for 2030 has been constructed with a 95% increase in the industrial output with only a 17% increase in the final energy demand (total final energy demand for industry (135 EJ)). The total direct and indirect carbon dioxide emissions from the industry sector in 2005 is about 9.9 GtCO 2 . Assuming a constant carbon intensity of energy use, the business as usual scenario results in carbon dioxide (CO 2 ) emissions increasing to 17.8 GtCO 2 annually in 2030. In the energy efficient scenario this reduces to 11.6 GtCO 2 . Renewables account for 9% of the final energy of industry (10 EJ in 2005). If an aggressive renewables strategy resulting in an increase in renewable energy supply to 23% in 2030 is targeted (23 EJ), it is possible to have a scenario of constant greenhouse gas (GHG) emissions by the industrial sector (at 2005 levels) with a 95% increase in the industrial output. Several interventions will be required to achieve the energy efficient or constant GHG emission scenario. For the existing industry measures include developing capacity for systems assessment for motors, steam systems and pinch analysis, sharing and documentation of best practices, benchmarks and roadmaps for different industry segments, access to low interest finance etc. A new energy management standard has been developed by ISO for energy management in companies. Its adoption will enable industries to systematically monitor and track energy efficiency improvements. In order to level the playing field for energy efficiency a paradigm shift is required with the focus on energy services not on energy supply per se. This requires a re-orientation of energy supply, distribution companies and energy equipment manufacturing companies. Planning for next generation processes and systems needs the development of long term research agenda and strategic collaborations between industry, academic and research institutions and governments

Adenylate effects on protein phosphorylation in the interenvelope lumen of pea chloroplasts

A 64-kilodalton (kDa) protein, situated in the lumen between the inner and outer envelopes of pea (Pisum sativum L.) chloroplasts (Soll and Bennett 1988, Eur. J. Biochem., 175, 301–307) is shown to undergo reversible phosphorylation in isolated mixed envelope vesicles. It is the most conspicuously labelled protein after incubation of envelopes with 33 nmol·1-1 [-32P]ATP whereas incubation with 50 mol·1-1 [-32P]ATP labels most prominently two outer envelope proteins (86 and 23 kDa). Half-maximum velocity for phosphorylation of the 64-kDa protein occurs with 200 nmol·1-1 ATP, and around 40 mol·1-1 ATP for phosphorylation of the 86- and 23-kDa proteins, indicating the operation of two distinct kinases. GGuanosine-, uridine-, cytidine 5-triphosphate and AMP are poor inhibitors of the labelling of the 64-kDa protein with [-32P]ATP. On the other hand, ADP has a potent influence on the extent of labelling (half-maximal inhibition at 1–5 mol·1-1). The ADP-dependent appearance of 32P in ATP indicates that ADP acts by reversal of kinase activity and not as a competitive inhibitor. However, the most rapid loss of 32P from pre-labelled 64-kDa protein occurs when envelope vesicles are incubated with ATP t1/2=15 s at 20 molsd1-1 ATP). This induced turnover of phosphate appears to be responsible for the rapid phosphoryl turnover seen in situ

Construction of a doxycycline inducible adipogenic lentiviral expression system

To provide a tool for research on regulating adipocyte differentiation, tetracycline inducible (Tet on) lentiviral expression vectors under the control of an adipose-specific promoter were constructed. The lowest basal expression in the absence of doxycycline and most efficient dose-dependent, doxycycline-induced transient overexpression was observed using vectors constructed with a combination of Tetracycline Responsive Element (TRE) and reverse tetracycline-controlled TransActivator advanced (rtTAadv), transfected in white (3T3-L1) and brown (HIB-1B) preadipocytes cell lines. The results demonstrate that doxycycline adipogenic inducible expression can be achieved using a pLenti TRE / rtTA adv under the control of the truncated aP2 promoter in HIB-1B preadipocytes

Scholarly communication in transition: The use of question marks in the titles of scientific articles in medicine, life sciences and physics 1966–2005

The titles of scientific articles have a special significance. We examined nearly 20 million scientific articles and recorded the development of articles with a question mark at the end of their titles over the last 40 years. Our study was confined to the disciplines of physics, life sciences and medicine, where we found a significant increase from 50% to more than 200% in the number of articles with question-mark titles. We looked at the principle functions and structure of the titles of scientific papers, and we assume that marketing aspects are one of the decisive factors behind the growing usage of question-mark titles in scientific articles

Reduction of Endothelial Nitric Oxide Increases the Adhesiveness of Constitutive Endothelial Membrane ICAM-1 through Src-Mediated Phosphorylation

Nitric oxide (NO) is a known anti-adhesive molecule that prevents platelet aggregation and leukocyte adhesion to endothelial cells (ECs). The mechanism has been attributed to its role in the regulation of adhesion molecules on leukocytes and the adhesive properties of platelets. Our previous study conducted in rat venules found that reduction of EC basal NO synthesis caused EC ICAM-1-mediated firm adhesion of leukocytes within 10–30min. This quick response occurred in the absence of alterations of adhesion molecules on leukocytes and also opposes the classical pattern of ICAM-1-mediated leukocyte adhesion that requires protein synthesis and occurs hours after stimulation. The objective of this study is to investigate the underlying mechanisms of reduced basal NO-induced EC-mediated rapid leukocyte adhesion observed in intact microvessels. The relative levels of ICAM-1 at different cell regions and their activation status were determined with cellular fractionation and western blot using cultured human umbilical vein ECs. ICAM-1 adhesiveness was determined by immunoprecipitation in non-denatured proteins to assess the changes in ICAM-1 binding to its inhibitory antibody, mAb1A29, and antibody against total ICAM-1 with and without NO reduction. The adhesion strength of EC ICAM-1 was assessed by atomic force microscopy (AFM) on live cells. Results showed that reduction of EC basal NO caused by the application of caveolin-1 scaffolding domain (AP-CAV) or NOS inhibitor, L-NMMA, for 30 min significantly increased phosphorylated ICAM-1 and its binding to mAb1A29 in the absence of altered ICAM-1 expression and its distribution at subcellular regions. The Src inhibitor, PP1, inhibited NO reduction-induced increases in ICAM-1 phosphorylation and adhesive binding. AFM detected significant increases in the binding force between AP-CAV-treated ECs and mAb1A29-coated probes. These results demonstrated that reduced EC basal NO lead to a rapid increase in ICAM-1 adhesive binding via Src-mediated phosphorylation without de novo protein synthesis and translocation. This study suggests that a NO-dependent conformational change of constitutive EC membrane ICAM-1 might be the mechanism of rapid ICAM-1 dependent leukocyte adhesion observed in vivo. This new mechanistic insight provides a better understanding of EC/leukocyte interaction-mediated vascular inflammation under many disease conditions that encounter reduced basal NO in the circulation system

Tuberculosis serosurveillance and management practices of captive African elephants (Loxodonta africana) in the Kavango-Zambezi Transfrontier Conservation Area

Transfrontier conservation areas represent an international effort to encourage conservation and sustainable development. Their success faces a number of challenges, including disease management in wildlife, livestock and humans. Tuberculosis (TB) affects humans and a multitude of non‐human animal species and is of particular concern in sub‐Saharan Africa. The Kavango‐Zambezi Transfrontier Conservation Area encompasses five countries, including Zimbabwe, and is home to the largest contiguous population of free‐ranging elephants in Africa. Elephants are known to be susceptible to TB; thus, understanding TB status, exposure and transmission risks to and from elephants in this area is of interest for both conservation and human health. To assess risk factors for TB seroprevalence, a questionnaire was used to collect data regarding elephant management at four ecotourism facilities offering elephant‐back tourist rides in the Victoria Falls area of Zimbabwe. Thirty‐five working African elephants were screened for Mycobacterium tuberculosis complex antibodies using the ElephantTB Stat‐Pak and the DPP VetTB Assay for elephants. Six of 35 elephants (17.1%) were seropositive. The risk factor most important for seropositive status was time in captivity. This is the first study to assess TB seroprevalence and risk factors in working African elephants in their home range. Our findings will provide a foundation to develop guidelines to protect the health of captive and free‐ranging elephants in the southern African context, as well as elephant handlers through simple interventions. Minimizing exposure through shared feed with other wildlife, routine TB testing of elephant handlers and regular serological screening of elephants are recommended as preventive measures.Financial support for elephant sample collection was provided by the Institute of Tropical Medicine, Antwerp, Belgium and the framework agreement (FA3) with the Belgian Development Cooperation, the National Research Foundation South African Research Chair Initiative (NRF SARChI), and the International Wildlife Health Institute. Laura Rosen was supported by a Morris Animal Foundation Veterinary Fellowship for Advanced Study (grant ID: D15ZO‐906).http://wileyonlinelibrary.com/journal/tbed2019-04-01hj2018Veterinary Tropical Disease