On modelling moisture buffering when evaluating humidity controlled HVAC systems

As most building energy simulation programs focus on the thermal response of the building, the relative humidity of the indoor air is often calculated in a simplified way. One of the main shortcomings is the isothermal calculation, which may have a strong influence the predicted relative humidity. In this paper the use of a simplified effective moisture penetration depth (EMPD) model is compared with a coupled TRNSYS-HAM-model. First, an estimation of the load for humidification and dehumidification is made. Results showed that the EMPD-model underestimates the humidification load because the model disregards non-isothermal effects. Secondly, calculations showed that the indoor and surface relative humidity of an office room with a gypsum cooled ceiling are overestimated using the EMPDmodel. Furthermore, due to not including nonisothermal effects the peak load for dehumidifying the ventilation air may be underestimated using an EMPD-model

The Tumor Necrosis Factor Superfamily of Cytokines in the Inflammatory Myopathies: Potential Targets for Therapy

The idiopathic inflammatory myopathies (IM) represent a heterogeneous group of autoimmune diseases, of which dermatomyositis (DM), polymyositis (PM), and sporadic inclusion body myositis (IBM) are the most common. The crucial role played by tumor necrosis factor alpha (TNFα) in the IM has long been recognized. However, so far, 18 other members of the TNF superfamily have been characterized, and many of these have not yet received the attention they deserve. In this paper, we summarize current findings for all TNF cytokines in IM, pinpointing what we know already and where current knowledge fails. For each TNF family member, possibilities for treating inflammatory diseases in general and the IM in particular are explored

Experimental investigation of the impact of room/system design on mixed convection heat transfer

Night cooling attracts growing interest. However, architects and engineers still hesitate to apply night cooling because of the important but hard-to-predict convective heat transfer by night. Obviously, this heat transfer mechanism depends on the driving force, fluid motion and heat transfer surface and, thus, on the room and system design. Unfortunately, studies addressing this are scarce. In response, underlying experimental effort intends to instigate global parametric analyses of night cooling at room level. To this end, this study, held in a PASLINK cell, investigates how the ventilative cooling rate, thermal mass and the supply/exhaust configuration affect the convective heat transfer. The analysis is based on airflow data, such as temperature and velocity, and the related convective heat flux. The results indicate the need for an integrated room/system design. After all, the position of the supply relative to thermally massive elements predominates the night cooling performance

Experimental analysis of the impact of room/system design on night ventilation performance

Night cooling attracts growing interest. However, building designers still hesitate to apply night cooling because of the important but hard-to-predict convective heat transfer by night. This heat transfer mechanism depends on the driving force, fluid motion and heat transfer surface and, thus, on the room/system design. Unfortunately, studies addressing this for night cooling regimes are scarce. In response, this study, held in a PASLINK cell, investigates how the ventilative cooling rate, thermal mass and the supply/exhaust configuration affect the convective heat transfer. The analysis is based on airflow data, such as temperature and velocity, and the related convective heat flux. The results indicate the air supply/exhaust configuration is particularly important in case of heterogeneously distributed thermal mass. Next to it, correlations should not be used when the setup and the convection regime differ a lot from those of the corresponding experiments

Economic optimization of heat exchangers for corrosive environments

Heat exchangers play a key role in power generation and many industrial processes. In various applications, the construction material is however exposed to a corrosive environment. This requires the device to be made from expensive corrosion resistant materials, causing the cost of the heat exchanger to increase significantly. One alternative could be to use more readily available metals (e.g. carbon steel). Although it might have to be replaced several times over its lifetime, the material cost of the heat exchanger would be more economical. In order to investigate if this is a viable alternative, a model was made. This model calculates the total cost of ownership (TCO) of a heat exchanger, taking into account the investment costs, maintenance costs and operational costs. A corrosion model is implemented allowing to specify the behaviour of a certain material in the fluid it is exposed to. Furthermore, the model allows to optimize the design to achieve a minimal TCO for a specific case. As a demonstration, the model is applied to the design and selection of an 5 MW heat exchanger for a binary geothermal power plant in Belgium, where the (corrosive) geothermal brine is used to heat water for a district heating network and an organic Rankine cycle

A bumpy ride on the diagnostic bench of massive parallel sequencing, the case of the mitochondrial genome

The advent of massive parallel sequencing (MPS) has revolutionized the field of human molecular genetics, including the diagnostic study of mitochondrial (mt) DNA dysfunction. The analysis of the complete mitochondrial genome using MPS platforms is now common and will soon outrun conventional sequencing. However, the development of a robust and reliable protocol is rather challenging. A previous pilot study for the re-sequencing of human mtDNA revealed an uneven coverage, affecting predominantly part of the plus strand. In an attempt to address this problem, we undertook a comparative study of standard and modified protocols for the Ion Torrent PGM system. We could not improve strand representation by altering the recommended shearing methodology of the standard workflow or omitting the DNA polymerase amplification step from the library construction process. However, we were able to associate coverage bias of the plus strand with a specific sequence motif. Additionally, we compared coverage and variant calling across technologies. The same samples were also sequenced on a MiSeq device which showed that coverage and heteroplasmic variant calling were much improved

Corrosion in heat exchangers in geothermal power plants

In geothermal power plants that use low to medium temperature geothermal reservoirs, electricity is generated using an organic Rankine cycle or heat is provided to district heating networks. The energy in the geothermal fluid is recovered with a heat exchanger. Since the temperatures and pressures are relative high (100-150°C, 40 bar), metallic heat exchangers are preferred. These are however susceptible to corrosion in the aggressive geothermal environment, so highly corrosion resistant materials should be used or suitable coatings should be applied. This has an adverse impact on the financial viability of the project. Therefore, this research investigates the possibility to use cheaper materials that come in contact with the brine. First, a model is described to determine the total cost of ownership of the heat exchanger and to determine an optimal design. Additionally, an experimental setup is described. This setup will allow to calibrate the corrosion parameters implemented in the model, to determine the influence of corrosion on the performance of the heat exchanger and to assess the influence of the flowing conditions on the corrosion process. In this paper, the methodology and expected outcome are described

Analytical calculation of fracture toughness of materials on tests of small-sized samples with a chevron notch

On the example of technical titanium VT1-0, a new technique for determining the crack resistance of materials is described in the data of tests of small-sized samples with a chevron notch. The problem of displacement the points of application of the part load due to the variation in the compliance of the sample during the propagation of a crack is solved. Equations for the calculation of the specific fracture energy from the experimental data of small-sized samples with a chevron notch are obtained