38 research outputs found
Foot-Operated Device for Controlling the Flow of Water into Plumbing Fixtures
For so many years the use of the hand - operated valve has been in existence for use to control water flow into plumbing fixtures. This research report outlines attempts to solve the problems arising from hand recontamination associated with the existing means of water flow using manual control valves and the harbouring and breeding of germs related to the automatic faucet by designing a device to be controlled by foot for regulating water flow into the plumbing fixtures. This device can be adopted for use in places like homes, hostels, schools, offices, restaurants, healthcare centres and other public places in general.The design employs the use of a helical compressive spring (under varying loads) as the major component for keeping the plug of the valve and the pedal of the actuator (both linked by a control rope) in position instead of the screw as employed in the hand - operated valves, as the main principle of operation.The maximum input force accommodated by the actuator in order to open the valve at full port is 36 N for users of ages ranging from 15 years and above. Difficulties encountered (but solved) included sizing components and drawing. Keywords: Hand – operated; Valve; Control; Water; Flow; Plumbing fixture
La traite des enfants au Togo : Un phenomene social a multiples causes.
The phenomenon of child trafficking in Togo raises an issue of development in its manifestations and consequences on families of victims and the providing areas. The driving objective of the research is to identify and explain favourable factors to the recruitment of children and their exploitation by traffickers. The research relies on the assumptions that socio cultural and economical conditions are parameters to child trafficking. Despite efforts in the fight against child trafficking spearheaded by state-based and non governmental institutions through establishment of legal framework and an increase in training and awareness raising sessions, the practise has not recorded much alleviation. Indeed, inasmuch as poverty, illiteracy, lack of job, deterioration of arable lands, lack of socio educational infrastructures and the desire to look like the other which characterise rural populations are not addressed, it is difficult to foresee a success whatever in the fight against child trafficking. Le phénomène de la traite des enfants au Togo pose un problème de développement quant à ses manifestations et ses conséquences sur les familles victimes et les localités pourvoyeuses. L’objectif quiconstitue le fil conducteur de la recherche consiste à identifier et à expliquer les facteurs favorables au recrutement des enfants et à leur exploitation par les trafiquants. La recherche a formulé l’hypothèse selon laquelle la traite des enfants est fonction des conditions socioculturelles et économiques. En dépit des efforts de lutte contre la traite des enfants, engagés par les institutions étatiques et non gouvernementales en créant un cadre juridique et en intensifiant des séances de formation et de sensibilisation, la pratique n’a pas connu une sensible réduction. En effet, tant que la pauvreté, l’analphabétisme, le manque d’emploi, la dégradation des terres arables, l’absence d’infrastructures socioéducatives et le désir de ressembler à l’autre qui sont caractéristiques des populations rurales ne sont pas résolus, il est difficile qu’on envisage du succès dans la lutte de la traite des enfants
Mouvement mutualiste au Togo : Une opportunite Pour la prise en charge communautaire des PVVIH
Associations and NGO of care for persons living with HIV (PLWHIV) are confronted with so huge difficulties that the outcomes of their activities are low. The effectiveness problematic of the care for persons living with HIV arises in terms of financial autonomy. In spite of the financial support from statebased and non governmental partner institutions, the Associations are never able to cater for the health, financial and psycho-social needs of their active component. The assumption which underlies the research believes that a participation of PLWHIV to their care is the basic to the success of the activities of these Associations. But the strategy which will enhance the inclusion of PLWHIV is to change the functioning of the Associations into a mutual system whose key features are solidarity and risks sharing through contributions or subscriptions. This practise shall be efficient only when Associations and NGO of care for PLWHIV get solutions to the numerous difficulties to which ordinary mutual health organization are confronted. Les Associations et ONG de prise en charge des personnes vivant avec le VIH (PVVIH) sont confrontées à d’énormes difficultés dans leurs activités à telle enseigne que leurs résultats sont mitigés. La problématique de leur efficacité dans la prise en charge des personnes vivant avec le VIH (PVVIH) se pose en termes d’autonomisation financière. En dépit du soutien financier des institutions partenaires tant étatiques que non gouvernementales, les Associations ne sont arrivées jamais à satisfaire les besoins sanitaires, alimentaires et psychosociaux de leur file active. Nous pensons que la participation des PVVIH à leur prise en charge constitue le fondement à la réussite des activités des Associations. Mais la stratégie qui pourra faciliter cette implication des PVVIH consiste à transformer le fonctionnement des Associations en système mutualiste caractérisé par la solidarité et le partage des risques à travers des cotisations ou des participations de toutes formes. Cette pratique ne peut être effective que lorsque lesAssociations et ONG de prise en charge des PVVIH trouveront des solutions aux multiples difficultés rencontrées par les mutuelles classiques de santé
Assessment of the water quality of boreholes in the Aburi municipality of eastern region of Ghana
Ground water samples from 32 boreholes in 17 communities within Aburi and its environs were sampled and analysed within the period of October 2008 to January 2009 for various physicochemical water quality parameters. The study showed that most of the physico-chemical parameters were within the World Health Organization limits recommended for drinking water. All the water samples were found to be colourless, with turbidity of 0.00 NTU. Temperature ranged from 24.0 to 28.0 oC, with an average of 26.21 ± 1.57 oC. The pH values ranged from 6.38 to 7.28with an average of 6.38 ± 0.21. The TDS of the water samples ranged from 13 to 522 mg/L with an average of 85.19 ± 53.85. Alkalinity levels were low ranging from 10 to 260.34 mg/L with a mean of 51.16 ± 37.51 mg/L whereas conductivity recorded values ranging from 18.98 to 240 ìS/cm and an average of 82.15 ± 43.10 ìµ/cm. The total hardness had a range of 25 to 301 mg/L with an average of 95.46 ± 59.01 mg/L. Most of the boreholes showed low level of mineralization. Low levels of nitrates ranging from 0.11 to 1.00 mg/L with an average of 0.665 ± 0.24 mg/L were recorded. Low levels of sulphate ranging from 35.35 to 200.48 mg/L with a mean of 93.75 ± 49.98 mg/L were obtained. Phosphate ion concentration ranging from 0.5 to 5.8 mg/L with an average of 2.64 ± 1.423 mg/L and chloride ion concentration ranging from 21.27 to 131.17 mg/L with a mean of 66.02 ± 30.28 mg/L were also obtained. All the water was found to be “salinityfree.” The study showed that the borehole water in the municipality is potable.Keywords: groundwater, borehole, physico-chemical, environ
Influence of temperature on titanium plasticity : diffraction techniques and mean-field approaches
Les alliages métalliques de structure hexagonale ont la particularité de présenter une forte anisotropie plastique et une grande variété de modes de déformation (glissement et maclage) dont l’activité dépend de nombreux facteurs. Selon la température et le mode de sollicitation mécanique, la déformation plastique dans les alliages de titane, en particulier le titane-α (Ti-α), présente un enchainement complexe d’activation de ces différents systèmes de glissements et de maclage, encore mal compris actuellement. Pour mieux appréhender le comportement mécanique du Ti-α, la méthode expérimentale privilégiée a été la diffraction des neutrons et des RX pour l’analyse fine des déformations intergranulaires développées durant les chargements en traction à différentes températures (de l’ambiant jusqu’à 300 °C).L’état mécanique du matériau aux différentes échelles (mésoscopique et macroscopique) a été analysé afin d’avoir des informations sur les mécanismes physiques régissant son comportement global.Une approche autocohérente élastoplastique a été adoptée pour expliquer les observations expérimentales durant les différents chargements thermomécaniques. Elle nous a permis de reproduire quantitativement la loi de comportement du polycristal et des groupes de grains sondés. Cette approche nous a également fourni des données pertinentes sur l’influence de la température sur l’état mécanique et l’anisotropie plastique d’un matériau comme le titane-α.Hexagonal close-packed metallic alloys develop a strong plastic anisotropy with a large variety of deformation modes (slip and twinning systems) which depends on many factors. Plastic deformation of titanium alloys, especially α-titanium (α-Ti), depends on temperature and mechanical loading mode. It is accommodated by a complex mixture of crystallographic slips and twinning. It remains though unclear which deformation systems are actually activated in the polycrystal during straining. In order to better understand the mechanical behavior of textured α-Ti, neutron and synchrotron X-ray diffraction measurements have been performed to analyze the intergranular strain evolution under tensile tests at different temperatures ranging from ambient up to 300 °C.The material have then been carefully characterized from meso-(grain) to macroscopic scales to obtain relevant information about the physical mechanisms governing its global behavior. An elastoplastic self-consistent approach has been used to explain and interpret the experimental observations achieved under thermomechanical loadings. The model enabled us to predict with success the measured macroscopic behavior and the lattice strain development. It has also provided a comprehensive data set on temperature influence onto the mechanical state and the plastic anisotropy, especially at the mesoscopic level
Biopolymer Flocculant Systems and Their Chemically Modified Forms for Aqueous Phosphate and Kaolinite Removal
The fate and build-up of phosphate (Pi) nutrients in aquatic environments is an urgent environmental problem affecting global water security. At elevated levels, Pi causes eutrophication, leading to oxygen depletion. This thesis is aimed at the development, optimization and application of a sustainable biopolymer-based coagulation-flocculation (CF) system that has improved Pi and turbidity (Ti) removal performance over conventional CF systems. In Chapters 3 and 4, the removal efficacy of Pi from wastewater was investigated using variable combinations of coagulant and biopolymer-flocculant (chitosan and alginate) systems. The CF process was affected by several independent variables (CF factors). The optimization studies provided an empirical relationship between the Pi removal efficiency and these factors. The results demonstrated that the biopolymer-flocculants are more efficient in a ternary system in removing Pi from wastewater and the process is controlled by charge neutralization and polymer-bridging mechanisms. Chapters 5 and 6 are aimed at designing a high molecular weight amphoteric bioflocculant (CMC-CTA) for the co-removal efficacy of Pi and Ti in a binary system with FeCl3. The effects of pH, settling time, coagulant and flocculant dosages were investigated through optimization studies, and the results showed that Fe(III)-CMC-CTA binary system was effective at acidic to neutral pH. Kinetics and equilibrium adsorption studies showed that the process was well described by kinetic pseudo-first-order and equilibrium Langmuir isotherm for uptake of Pi and Ti and the process was spontaneous and endothermic. Chapter 7 focused on the design of high molecular weight cationic chitosan-based flocculant (CTA-Chi-g-PAM). The functional properties of the flocculants were examined for the removal of Pi, and Ti, where the effects of several CF factors were tested in a single-component system. The experimental data were fitted by several kinetic (time-dependent) and adsorption (concentration dependent) models. Thermodynamic parameters revealed that the CF process was favored by entropy-driven electrostatic interactions and polymer bridging. Individual kaolinite-colloidal particles showed a higher aggregation rate due to Coulombic electrostatic and van der Waals attractive forces in the presence of CTA-Chi-g-PAM to form flocs. The studies reported herein provide a greater understanding of the structure-property relationship for biopolymer-based CF phenomena, and the findings will add to the design of bioflocculants with superior and tunable physicochemical properties
Flocculation Optimization of Orthophosphate with FeCl<sub>3</sub> and Alginate Using the Box–Behnken Response Surface Methodology
A coagulation–flocculation
process was employed to remove
orthophosphate (P<sub>i</sub>) in aqueous media using a ferric chloride
(FeCl<sub>3</sub>) and alginate flocculant system. Jar tests were
conducted, and the response surface methodology (RSM) was used to
optimize the P<sub>i</sub> removal variables. The Box–Behnken
design was used to evaluate the effects and interactions of four independent
variables: pH, FeCl<sub>3</sub> dose, alginate dose, and settling
time. The RSM analysis showed that the experimental data followed
a quadratic polynomial model with optimum conditions at pH 4.6, [FeCl<sub>3</sub>] = 12.5 mg·L<sup>–1</sup>, [alginate] = 7.0 mg·L<sup>–1</sup>, and a 37 min settling time. Optimum conditions led
to a P<sub>i</sub> removal of 99.6% according to the RSM optimization,
in good agreement with experimental removal (99.7 ± 0.7%), at
an initial concentration of 10.0 mg P<sub>i</sub>/L. The isotherm
adsorption data at the optimized conditions were analyzed by the pseudo-first-order
(PFO) and pseudo-second-order (PSO) kinetic models and several isotherms
models (Langmuir, Freundlich, and Sips). The PFO kinetic model and
Langmuir isotherm model yielded the best fit to the isotherm results.
The maximum adsorption capacity of the flocculant system was 83.6
mg·g<sup>–1</sup>. The flocculation process followed electrostatic
charge neutralization and an ion-binding adsorption mechanisms
Emotional-motivational barriers to blood donation among Togolese adults: a structural approach
Optimisation of orthophosphate and turbidity removal using an amphoteric chitosan-based flocculant–ferric chloride coagulant system
Investigation of α-Ti plastic anisotropy under thermomechanical loadings: temperature influence on deformation mechanisms
In situ neutron diffraction method has been used to investigate deformation mechanisms (slip and twinning deformation modes) during uniaxial tensile tests of extruded a-titanium alloy at room temperature, 100 and 300 °C. For this purpose, the prediction of an Elasto-Plastic Self-Consistent (EPSC) model was compared with the experimental data. Results show that there is a good agreement between the simulations and neutron diffraction measurements. The EPSC model enables realistic predictions of not only the elastic lattice strains developed in variously oriented grain families but also the macroscopic stress-strain response within the bulk material