40 research outputs found
Health in Rural Tanzania: The Determinants of Health Status, Health Care Demand and Health Care Choice
No full textIn Tanzania, health statistics have shown slow improvement, although spending on health services in Tanzania is quite high. Defining the determinants of both health status and health use is interesting to point out possibilities for policy. Using household data of the rural Tanzanian mainland, one indicator of health status, the incidence of illness, is examined here and three health demand variables, the incidence of treatment, the level and the provider of treatment. For health outcome as well as health demand, the importance of household income in Tanzania is striking. A positive cross-effect of education on health could not be identified, except for rich Tanzanians. Distance to the nearest health facility does not matter for the poorest patients. Although the measurement of quality is problematic, the quality of the lower level medical care is found to have a positive impact on health status and on health demand, more specifically the nonwage component of quality. These results indicate that the introduction of cost recovery schemes in the Tanzanian health system may have perverse effects, if not combined with a price differentiation according to income and an improvement of quality of health facilities.
Digitale temperatuursmetingen met TINI
No full textMicroprocessoren worden steeds meer gebruikt in moderne elektronicatoepassingen. Dallas
semiconductors ontwikkelde een platform waarmee met behulp van een microprocessor een
code voor webservers kan uitgevoerd worden: TINI ofwel Tiny InterNet Interfaces. Dit
platform is een combinatie van een full TCP/IP stack en een runtime environment die de
ontwikkeling van netwerktoepassingen vergemakkelijkt.
Deze scriptie beschrijft hoe men temperaturen kan meten en verwerken met behulp van een
TINI en een iButton. De gebruikte iButton is een DS1921G temperatuurslogger die op het
TINI platform kan worden geplaatst. Hiermee kunnen bedrijven hun klanten onder andere de
garantie geven, dat hun product binnen vooropgestelde temperatuursgrenzen gebleven is. In
de voedingsindustrie zijn er veel toepassingen van te vinden. De temperaturen kunnen
uitgelezen worden met corresponderende tijd en de metingen worden grafisch voorgesteld,
waardoor makkelijk kan nagegaan worden waar bepaalde temperatuursgrenzen zijn
overschreden.
Om het eindwerk tot een goed eind te brengen, was een goed inzicht nodig in het 1-Wire
protocol waarmee de TINI werkt. De programmering gebeurde in C en om enkele
voorbeeldprogramma\u27s uit te voeren werd Linux gebruikt
Report of RILEM TC 281-CCC: outcomes of a round robin on the resistance to accelerated carbonation of Portland, Portland-fly ash and blast-furnace blended cements
No full textMany (inter)national standards exist to evaluate the resistance of mortar and concrete to carbonation. When a carbonation coefficient is used for performance comparison of mixtures or service life prediction, the applied boundary conditions during curing, preconditioning and carbonation play a crucial role, specifically when using latent hydraulic or pozzolanic supplementary cementitious materials (SCMs). An extensive interlaboratory test (ILT) with twenty two participating laboratories was set up in the framework of RILEM TC 281-CCC ‘Carbonation of Concrete with SCMs’. The carbonation depths and coefficients determined by following several (inter)national standards for three cement types (CEM I, CEM II/B-V, CEM III/B) both on mortar and concrete scale were statistically compared. The outcomes of this study showed that the carbonation rate based on the carbonation depths after 91 days exposure, compared to 56 days or less exposure duration, best approximates the slope of the linear regression and those 91 days carbonation depths can therefore be considered as a good estimate of the potential resistance to carbonation. All standards evaluated in this study ranked the three cement types in the same order of carbonation resistance. Unfortunately, large variations within and between laboratories complicate to draw clear conclusions regarding the effect of sample pre-conditioning and carbonation exposure conditions on the carbonation performance of the specimens tested. Nevertheless, it was identified that fresh and hardened state properties alone cannot be used to infer carbonation resistance of the mortars or concretes tested. It was also found that sealed curing results in larger carbonation depths compared to water curing. However, when water curing was reduced from 28 to 3 or 7 days, higher carbonation depths compared to sealed curing were observed. This increase is more pronounced for CEM I compared to CEM III mixes. The variation between laboratories is larger than the potential effect of raising the CO2 concentration from 1 to 4%. Finally, concrete, for which the aggregate-to-cement factor was increased by 1.79 in comparison with mortar, had a carbonation coefficient 1.18 times the one of mortar.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Materials and Environmen
Biosensors in Forensic Sciences
No full textA biosensor is a device that uses biological materials to detect and monitor the presence of specific chemicals in an area. Traditional methods of volatile detection used by law enforcement agencies and rescue teams typically consist of reliance on canine olfaction. This concept of using dogs to detect specific substances is quite old. However, dogs have some limitations such as cost of training and time of conditioning. Thus, the possibility of using other organisms as biosensors including rats, dolphins, honeybees, and parasitic wasps for detecting explosives, narcotics and cadavers has been developed. Insects have several advantages unshared by mammals. Insects are sensitive, cheap to produce and can be conditioned with impressive speed for a specific chemical-detection task. Moreover, insects might be a preferred sensing method in scenarios that are deemed too dangerous to use mammals. The purpose of this review is to provide an overview of the biosensors used in forensic sciences
Effect of precursors and water to binder ratios on the water permeability of alkali-activated mortars
No full textThis work investigates the water permeability of alkali-activated materials (AAMs), which is one of the key transport properties beside the diffusivity to assess the material durability. The AAMs were produced from granulate blast furnaces slag (BFS) and metakaolin (MK) with various water/binder ratios of 0.35, 0.45, 0.55, and 0.75, 0.85, 0.95 for BFS and MK based AAMs, respectively. Herein, a direct method using a constant flow controlled by a syringe pump, which has been successfully applied on conventional concrete, was used to measure the permeability of the AAMs. Data was then compared with the OPC mortars with similar w/b ratios. The results reveal that the permeability of BFS activated mortars is comparable to the one of OPC mortars. Both BFS and MK based AMMs are highly sensible with the changes in w/b ratio. The higher the w/b ratio, the higher the permeability. The extent in changing permeability with w/b ratio is stronger for BFS compared to MK based AMMs. Furthermore, a correlation between water permeability and microstructure obtained by nitrogen adsorption of the investigated AAMs is highlighted, which indicates that the permeability of MK based mortars is mostly controlled by capillary pores, while gel pores significantly affect the permeability of BFS based mortars
The compatibility of transmission electron microscopy and micro Raman spectroscopy: application to parchment illustrations
No full textEvaluation of a Long-Term Thermal Load on the Sealing Characteristics of Potential Sediments for a Deep Radioactive Waste Disposal
No full textAn in situ and a batch heating experiment were applied on the fine-grained sediments of the Opalinus Clay from Mont Terri (Switzerland) and the Boom Clay of Mol (Belgium), both being currently studied as potential host formations for deep nuclear waste disposal. The purpose was here to test the impact of a 100 °C temperature rise that is expected to be produced by nuclear waste in deep repositories. The experiment on the Opalinus Clay mimicked real conditions with 8-months operating heating devices stored in core drillings into the rock. The comparison of the major, trace, rare-earth elemental contents and of the whole-rock K-Ar data before and after heating shows only a few variations beyond analytical uncertainty. However, the necessary drillings for collecting control samples after the experiment added an unexpected uncertainty to the analyses due to the natural heterogeneity of the rock formation, even if very limited. To overcome this aspect, Boom Clay ground material was subjected to a batch experiment in sealed containers during several years. The drawback being here the fact that controls were limited with, however, similar reproducible results that also suggest limited elemental transfers from rock size into that of the <2 μm material, unless the whole rocks lost more elements than the fine fractions. The analyses generated by the two experiments point to identical conclusions: a visible degassing and dewatering of the minerals that did not induce a visible alteration/degradation of the host-rock safety characteristics after the short-term temperature increase
Microstructural evolution and its impact on the mechanical strength of typical alkali-activated slag subjected to accelerated carbonation
No full textInternational audienceThis study aims to comprehensively investigate the evolution of microstructure, mechanical strength, and their correlation in alkali-activated slag (AAS) mortars, designed for application in the immobilization of liquid radioactive waste, under accelerated carbonation conditions (1% CO2, 20 °C and 60% RH). To gain insights into the underlying microstructural changes, CO2 uptake and decalcification of C-A-S-H were analyzed using TGA/DSC and EDS. The pore structure of AASs was systematically assessed across nano- to macro-scales, employing N2-adsorption, MIP, and SEM segmentation. Generally, carbonation led to a decrease in total porosity, primarily attributed to the reduction in meso-macropore volume. However, the pore size distribution of AAS exhibited a complex alteration over varying carbonation durations. Carbonation significantly reduced flexural strength, whereas its effect on compressive strength was comparatively milder. Notably, an evident linear correlation emerged between porosity and compressive strength in both reference and carbonated AASs
Epoxy-Induced Spalling of Silicon
No full textAbstractOne of the main driving forces to lower the silicon solar cell modules overall cost is to decrease the thickness of the silicon substrate and, at same time, to reduce the material losses caused by the sawing of the silicon ingot. For this reason, a considerable number of methods have been proposed in the last decade to manufacture thin silicon foils which aim to replace the commonly used sawing technique. One of these methods is based on peeling off a thin layer from a silicon substrate by means of the residual stress induced either through the only deposition of a layer on a silicon substrate or through a succeeding thermal cycle of such a bilayer. Up to now, three different materials have been successfully employed in this technique: Nickel, Nickel/Chromium alloy and a Silver/Aluminium system. In this work we demonstrate the possibility to induce the lift-off of a thin silicon foil by means of curing an epoxy layer on top of a silicon wafer. This new method has the advantages of reducing metal contamination in the silicon and lowers the operating temperatures below 150°C
Free Energy Landscape and Dynamics of Supercoiled DNA by High-Speed Atomic Force Microscopy
No full textDNA supercoiling fundamentally constrains and regulates the storage and use of genetic information. While the equilibrium properties of supercoiled DNA are relatively well understood, the dynamics of supercoils are much harder to probe. Here we use atomic force microscopy (AFM) imaging to demonstrate that positively supercoiled DNA plasmids, in contrast to their negatively supercoiled counterparts, preserve their plectonemic geometry upon adsorption under conditions that allow for dynamics and equilibration on the surface. Our results are in quantitative agreement with a physical polymer model for supercoiled plasmids that takes into account the known mechanical properties and torque-induced melting of DNA. We directly probe supercoil dynamics using high-speed AFM imaging with subsecond time and ∼nanometer spatial resolution. From our recordings we quantify self-diffusion, branch point flexibility, and slithering dynamics and demonstrate that reconfiguration of molecular extensions is predominantly governed by the bending flexibility of plectoneme arms. We expect that our methodology can be an asset to probe protein-DNA interactions and topochemical reactions on physiological relevant DNA length and supercoiling scales by high-resolution AFM imaging.sponsorship: We thank C. Broedersz, S. Granick, H. Gaub, M. Benoit, and W. Frederickx for discussions, A. Katan and K. Douglass for sharing the worm-like chain simulation code, K. Cermakova for help with protein purification, and Z. Debyser for use of laboratory equipment. We acknowledge funding from KU Leuven through an IDO grant and the Junior Mobility Programme (to T.B.), from the Deutsche Forschungsgemeinschaft through SFB 863 project All, and from the Fonds Wetenschappelijk Onderzoek through a personal fellowship (to W.V.). H.D.K. acknowledges a Visiting Scientist position at Bio-AFM FRC, supported by a grant from the MEXT Japan (#15K21711 to TA.). (KU Leuven through an IDO grant, Deutsche Forschungsgemeinschaft|SFB 863, Fonds Wetenschappelijk Onderzoek, MEXT Japan|15K21711, KU Leuven through Junior Mobility Programme, Grants-in-Aid for Scientific Research|15K21711)status: Publishe
